Category Archives: Guest Blogs

From the Lab to Your Pocket: Groundbreaking Leg Power Measurement With Your iPhone

Ladies and gentlemen (especially athletes, strength coaches, and sports scientists),

I’m very excited to present to you some incredible brand new technology. Imagine an iPhone app that allows athletes and coaches to:

  1. Calculate jump height based on the iPhone’s video capture capabilities
  2. Create a force-velocity profile by performing several jumps with varying loads
  3. Compare the force-velocity profile to an ideal force-velocity profile, thus providing individualized training recommendations

Previously, this required expensive equipment, but now it’s available for mass usage if you have an iPhone or iPad. The app is called My Jump, and it can be yours today for only $6. Yes, you read that properly – just six dollars! In addition, My Jump:

  1. Is highly valid and reliable when compared to data obtained on a $12,000 force plate
  2. Provides individualized training recommendations, which will expedite your progress

Reason why? Until now, the vast majority of strength coaches prescribe the same power training programs to every athlete. This is due to the fact that they have not been privy to the athlete’s unique force-velocity profile. Knowing how the athlete’s force-velocity profile compares to the ideal force-velocity profile allow for individualized training. Recently, this individualization has been found to lead to better performance results than traditional power training methods that are not individualized (publication in progress).

I’ve longed for an invention like this for many years. Heck, I’d pay $6 for an app that simply calculated jump height, but this app goes the extra mile and tells me exactly how I should be training in order to best improve my vertical jump performance. How freakin’ cool is that?! You can use this app with your clients and athletes if you’re a personal training or strength coach, or to conduce experiments if you’re a sports science researcher.

Click HERE to purchase My Jump for $6 (not an affiliate link)

Below is a guest article from the inventors of the app.

From the Lab to Your Pocket: Groundbreaking Lower-Limbs Power Measurement With Your iPhone 

by Carlos Balsalobre, Pierre Samozino and Jean-Benoit Morin

Introduction: Jump height as a measure of lower-limbs explosive performance

Explosive movements such as vertical jumps, change of direction, and the first few steps of running, are some of the most frequent activities in a wide range of sports (4,6,11). Basketball, soccer, volleyball, martial arts, and gymnastics each require explosive push-offs in order to succeed in several specific tasks in competition. Vertical jump performance has been used to assess these lower limb explosive capabilities. Many studies show that vertical jumping ability is a good indicator of lower-limbs strength, power or short sprint times (10,12). So, in fact, every athlete involved in any power/explosive sport would need to perform great jumps as a measure of his/her lower limbs explosive capabilities.

But vertical jumping ability not only represents the athletes’ explosive capabilities, it is also a great tool to know the levels of fatigue induced by training and practice (17). For example, it was demonstrated that the jump height decrease observed between the beginning and the end of a back squat training session is very highly correlated to the levels of blood lactate produced (a metabolite associated fatigue); thus, the higher the jump decreases, the higher the blood lactate concentrations.

For those reasons, many researchers have studied and designed different jumping tests to evaluate athletes’ lower limbs performance during the last decades (1,3,13). French scientist and pioneer of motion analysis Etienne-Jules Marey made one of the first attempts in history before 1900.


More recently, based on an equation derived from the Newtonian laws of motion, and used by Asmussen and Bonde-Petersen (1), Bosco designed a widespread battery of tests to assess jumping abilities. These tests included squat jumps, countermovement jumps, drop-jumps or repeated jumps.

However, the most popular tests focusing on explosive capabilities (i.e. squat jump and counter movement jump) have the main limitations of not providing power values or information about their force and velocity components. This is mainly because they do not account for the length of leg push-off distance during the push-off phase, which significantly influences power output. Even if mechanical power output is often estimated via regression equations based on jump height, this approach provides only an indirect estimation associated to a very poor accuracy.

To tackle these issues, Samozino and colleagues published a simple method allowing for simple and accurate computations of force, velocity and power outputs during a vertical jump, on the basis of body mass, lower limbs length and jump height (15). 

Force-Velocity profile and power output in squat jumlp for a 75kg male subject who jumped 30.8, 26.5, 23.5, 17.1 and 14.9 cm while carrying additional loads of 0, 10, 20, 40 and 50 kg, respectively.

Force-Velocity profile and power output in squat jump for a 75kg male subject who jumped 30.8, 26.5, 23.5, 17.1 and 14.9 cm while carrying additional loads of 0, 10, 20, 40 and 50 kg, respectively.

Then, in order to know the full range of force and velocity capabilities of an athlete, these authors proposed, on the basis of several jumps with various additional loads, to draw the linear “force-velocity profile”. This relationship basically describes, for each individual, the entire profile of his/her force and velocity capability, from the theoretical maximal force “usually called F0”, to the theoretical maximal velocity (V0) the lower limbs neuromuscular system can produce. The slope of this relationship, i.e. the F-V profile describes the orientation of the athlete’s system towards force or velocity qualities, and which of these mostly determine its power output (14).

The optimal Force-Velocity Profile approach to optimize your performance

Many studies have analyzed the effects of different training programs to improve vertical jump performance (6,8,18). However there is no consensus about what kind of loads and exercises should be used to improve explosive performance, since both heavy resistance training exercises (i.e. back squat with 85%RM) and light/ballistic exercises (i.e., 30%RM, plyometrics) have been probed to increase vertical jumping abilities. It is well known that power output depends on both the force and velocity produced in a certain exercise (15); therefore, increasing velocity (via high-speed, light exercises) or force (or maximal strength, via low-speed, heavy exercises) capabilities might increase vertical jump performance. The question is: in what proportion should we train force and velocity capabilities to best increase our athletes’ vertical jump height?

Samozino and colleagues recently showed, on the basis of a mathematical modeling of jump performance, that there is, for each individual, an optimal value of F-V profile (slope of the linear relationship) that maximizes (all other things, including maximal power, being equal) jump height (16). In other words, for a given maximal power, among the various force and velocity capabilities combinations that lead to these power qualities, only one will result in a maximized jump performance. This optimal combination, called “optimal force-velocity profile” is individual and can be easily determined using the simple method described above. Should your profile be too much force- or velocity-oriented compared to your optimal profile, your jump performance (and more in general, your explosive performance) is lower than what it could be. This analysis led to the concept of individual “force-velocity imbalance” and was shown to be directly related to jump performance (14). Research in progress will show how to “re-orient” athletes’ individual profile via individualized, optimized training regimen, and that this results in better improvements of jump height than traditional strength training not taking account of the individual F-V imbalance of the athletes (publication in process).

The F-V profile of the subject presented in the previous figure (black line) compared to his individual optimla profile computed from Samozino et al.’s 2012 equation (blue dashed line). The F-V imbalance (% difference between actual and optimal profiles) for this subject is 30%. This means that, for a same given power oputput, should this subject train to increase his force capabilities in jumping, he will decrease his F-V imbalance, shift his profile towards his optimal value, and in turn increase his jump height.

The F-V profile of the subject presented in the previous figure (black line) compared to his individual optimal profile computed from Samozino et al.’s 2012 equation (blue dashed line). The F-V imbalance (% difference between actual and optimal profiles) for this subject is 30%. This means that, for a same given maximal power output, should this subject train to increase his force capabilities in jumping, he will decrease his F-V imbalance, shift his profile towards his optimal value, and in turn increase his jump height. If, at the same time, he does not decrease his velocity capabilities, he would also increase his Pmax, and in turn increase his jump height to an even larger extent

My Jump app: Powerful & accurate jump measurements with your iPhone

As stated above, the measurement of the vertical jump height of the athletes is a simple input variable that can be used to provide great information about their lower-limb force-velocity-power capabilities and explosive performance ability, and in turn it helps optimize training programs to maximize gains. Thus, vertical jump assessment is a must for many S&C coaches. Sport scientists have been using different technologies, such as force, contact or infrared systems to accurately measure jump height (5,7,9). These technologies calculate the height of vertical jumps from the measurement of flight time, since fundamental laws of physics establish that the height reached by the center of mass of the subject depends on the time he/she is able to stay in the air during the jump (1).

This approach is highly accurate and it is widely used by sport scientists, researchers and coaches around the world; however, jump systems have a major drawback that prevent their use out of laboratories, Universities or big sports centers: they are still too expensive for regular coaches (for example, one of the most popular system, the Optojump, costs about $2,000). To avoid this great limitation and bring accurate vertical jump measurements to many sport coaches and field practitioners, Carlos Balsalobre, a Spanish sport scientist, designed an app for iPhone & iPad (named My Jump) that accurately calculates vertical jump height, as shown in the validation paper recently published in Journal of Sports Sciences (2).

To do this, My Jump uses the high-speed video recording on the iPhone 5s, iPhone 6/6 Plus or iPad Air 2 to record the vertical jumps (120 or 240 frames per second depending on the model). Measuring the height of a vertical jump with My Jump is quite simple: you have to record a video of the feet of the athlete while jumping, and then you just need to select the frame in which the subject leaves the ground and the frame in which he/she lands, and the app calculates the jump height through the flight time.

User interface of My Jump app. After a jump has been recorded, the user can navigate the video frame by frame to select the take-off and landing moments

User interface of My Jump app. After a jump has been recorded, the user can navigate the video frame by frame to select the take-off and landing moments

To test its validity and reliability, Carlos and his colleagues measured 100 jumps in different subjects using My Jump and a $10,000 force platform simultaneously, and then compared the results. We are going to skip advanced statistics stuff but, basically, they showed that My Jump on an iPhone 5s (which records videos at 120 frames per second) provides jump height values with the same reliability as the force platform and a mean difference between these two systems of just 12mm. Moreover, the recent iPhone 6/6 Plus incorporates an enhanced high-speed camera of 240fps, so the accuracy is even better with these devices.

Recently, Pierre Samozino and JB Morin (see our recent interview of JB here) – the sport scientists and fathers of the optimal F-V profile method described above, collaborated with Carlos Balsalobre to incorporate the published F-V profile calculations (14–16) in the updated version of his app. After several weeks of design and validation testing, Carlos and the French iOS developer he works with, Francis Bonnin, were able to release the new version of My Jump that includes Pierre’s and JB’s Optimal F-V profile calculation. Therefore, My Jump can now be used to perform an advanced evaluation of the lower limbs explosive capabilities using just an iPhone or iPad. And that is how technology met science to simplify and improve field practice, packing the theory with several recent scientific publications and validated equations in an accurate <6$ mobile device app.

F-v profile results screen of My Jump. Optimal and actual F-v profiles, as well as F0, v0, Pmax and F-v imbalance are calculated.

F-v profile results screen of My Jump. Optimal and actual F-v profiles, as well as F0, v0, Pmax and F-v imbalance are calculated.

Practical implications 

The optimal F-V profile method is an excellent approach to evaluate your athletes’ lower-limbs explosive performance and can help to optimize your training programs taking into account the specific individual f-v capabilities of each subject.

This advanced lower-limbs evaluation can now be performed in an accurate, reliable, non-expensive way using My Jump in your iPhone or iPad. My Jump is available on the Appstore for just $5.99 – click HERE for the link. You can find more information about My Jump in its Twitter, Facebook or YouTube accounts.


  1. Asmussen, E and Bonde-Petersen, F. Storage of elastic energy in skeletal muscles in man. Acta Physiol Scand 91: 385–92, 1974.
  2. Balsalobre-Fernández, C, Glaister, M, and Lockey, RA. The validity and reliability of an iPhone app for measuring vertical jump performance. J Sports Sci , 2015.
  3. Bosco, C, Luhtanen, P, and Komi, P V. Simple method for measurement of mechanical power in jumping. Eur J Appl Physiol 50: 273–282, 1983.
  4. Buchheit, M, Spencer, M, and Ahmaidi, S. Reliability, Usefulness, and Validity of a Repeated Sprint and Jump Ability Test. Int J Sport Physiol Perform 5: 3–17, 2010.
  5. Caireallain, AO and Kenny, IC. Validation of an electronic jump mat. Int Symp Biomech Sport Conf Proc Arch 28: 1–4, 2010.
  6. Chaudhary, C and Jhajharia, B. Effects of plyometric exercises on selected motor abilities of university level female basketball players. Br J Sports Med 44: i23–i23, 2010.
  7. Glatthorn, JF, Gouge, S, Nussbaumer, S, Stauffacher, S, Impellizzeri, FM, and Maffiuletti, NA. Validity and reliability of Optojump photoelectric cells for estimating vertical jump height. J Strength Cond Res 25: 556–560, 2011.
  8. Hartmann, H, Wirth, K, Klusemann, M, Dalic, J, Matuschek, C, and Schmidtbleicher, D. Influence of squatting depth on jumping performance. J Strength Cond Res 26: 3243–3261, 2012.
  9. Hertogh, C and Hue, O. Jump evaluation of elite volleyball players using two methods: jump power equations and force platform. J Sport Med Phys Fit 42: 300–303, 2002.
  10. Kale, M, Asci, A, Bayrak, CI, and Acikada, C. Relationships among jumping performances and sprint parameters during maximum speed phase in sprinters. J Strength Cond Res 23: 2272–2279, 2009.
  11. López-Segovia, M, Marques, MC, Vam den Tillaar, R, and González-Badillo, JJ. Relationships Between Vertical Jump and Full Squat Power Outputs With Sprint Times in U21 Soccer Players. J Hum Kinet 30: 135–144, 2011.
  12. Loturco, I, D’Angelo, RA, Fernandes, V, Gil, S, Kobal, R, Cal Abad, CC, et al. Relationship between sprint ability and loaded/unloaded jump tests in elite sprinters. J Strength Cond Res , 2014.
  13. Marey, E. Le Mouvement. Paris: Ed. Masson, 1984.
  14. Samozino, P, Edouard, P, Sangnier, S, Brughelli, M, Gimenez, P, and Morin, JB. Force-velocity profile: imbalance determination and effect on lower limb ballistic performance. Int J Sport Med 35: 505–510, 2014.
  15. Samozino, P, Morin, JB, Hintzy, F, and Belli, A. A simple method for measuring force, velocity and power output during squat jump. J Biomech 41: 2940–2945, 2008.
  16. Samozino, P, Rejc, E, Di Prampero, PE, Belli, A, and Morin, JB. Optimal force-velocity profile in ballistic movements–altius: citius or fortius? Med Sci Sport Exerc 44: 313–322, 2012.
  17. Sanchez-Medina, L and González-Badillo, JJ. Velocity Loss as an Indicator of Neuromuscular Fatigue during Resistance Training. Med Sci Sport Exerc 43: 1725–1734, 2011.
  18. Thompson, BJ, Stock, MS, Shields, JE, Luera, MJ, Munayer, IK, Mota, JA, et al. Barbell deadlift training increases the rate of torque development and vertical jump performance in novices. J Strength Cond Res 29: 1–10, 2015.

How to Maximize Concurrent Training

How to Maximize Concurrent Training
By Marc Lewis

Simultaneously training for adaptations associated with resistance and endurance training (RT & ET), otherwise known as concurrent training (CT), is widely debated by fitness professionals and strength coaches alike. CT has been criticized due to the potential for chronic overreaching, as well as the competing adaptations associated when performing RT and ET, concurrently. However if programmed carefully, CT can produce a lean and sculpted physique, while obtaining a high level of fitness as measured by health aspects as well as athletic parameters. Therefore, the purpose of this article is to elucidate the ways in which the adaptations associated with both RT and ET can be maximized when training concurrently.

In 1980, Dr. Robert Hickson introduced the concept of “interference” when training for adaptations associated with both RT and ET simultaneously (1). Currently, it is generally accepted that you cannot fully maximize skeletal muscle hypertrophy, strength, and power, while engaging in an aggressive ET program. Nevertheless, there is a growing body of literature supporting the theory that high-intensity RT not only does not impede adaptations associated with ET, it can actually improve endurance performance (2-11). Furthermore, it has been postulated that ET may not significantly blunt adaptations associated with RT, and can accelerate a reduction in fat mass as well as improve sleep, and cardiac efficiency (12-15).


The Interference Theory

As previously mentioned, the interference theory originated from some pioneering research by Dr. Robert Hickson in 1980. Dr. Hickson investigated the training affects of a high frequency, high volume CT program, which utilized running as the ET modality and compared it to strength or endurance training alone over a ten-week period (1). Dr. Hickson found that strength increased in the CT group until approximately weeks 6-7, which was followed by a “leveling-off period” and a sharp decrease in strength the final two weeks (1). Additionally, Dr. Hickson noted no statistically significant differences in aerobic capacity between the ET only group and the CT group. Nevertheless, there were a couple of interesting outcomes associated with body composition. The CT group decreased their body fat significantly (p <0.05), and to a greater extent than either the ST only or ET only groups (1). Furthermore, the CT group increased their thigh girth 54.7 to 56.4 cm (p <0.05), which was similar to the strength only group 53.3 to 55.5 cm (p <0.01) (1). This is an indication of type I muscle fiber hypertrophy, which is commonly seen in certain endurance athletes such as cyclists or cross-country skiers.

Dr. Hickson’s results provided the foundational research concerning the inference phenomenon, while setting the platform from which many other investigations were launched. Rather than discuss every significant study conducted in the past 35 years, this article will provide you with the rationale for competing adaptations, discuss the benefits associated with RT and ET alone, as well as provide a set of practical recommendations to maximize RT and ET adaptations when training concurrently.

Inference Effects and Competing Adaptations

Two points are crystal clear from the current literature: 1) inference effects are multifactorial, and 2) there is a dose-response relationship between ET volume (i.e. frequency & duration) and its potential negative effects on RT outcomes. Interference is thought to be a combination of chronic overreaching, which can lead to overtraining, and long-term competing adaptations at the cellular level (16). In addition, the dose-response relationship that exists with increased ET volume does not appear to exist to the same extent with RT volume when examining endurance outcomes (i.e. VO2max, aerobic enzymatic activity, etc) (2-11). In fact, RT has been shown in numerous studies to improve endurance performance directly (i.e. time trial) (8, 17), as well as endurance parameters (VO2max and running/cycling economy) (2-11, 17). Furthermore, high-intensity RT (loads >85% 1RM) paired with explosive, high velocity RT has been suggested to be a superior method of RT in recreationally trained, highly trained, and elite endurance athletes (3-6, 8-9, 12, 18).

Chronic overreaching, and ultimately overtraining, is theorized to be a product of high volume, high intensity, and/or high frequency training bouts over an extended period of time (16). This theory is generally termed the “chronic hypothesis,” and is limited in its literary support. These effects are suggested to be exacerbated when the training bouts involve large muscle groups and excess exercise-induced muscle damage, as seen in repetitive eccentric contractions (i.e. running) (12, 16). ET has a natural high volume component, therefore, when combined with high volumes of RT it can be suggested that an overreaching stimulus could be created over time (12, 16). Therefore, when structuring a CT program it can be theorized that strategically programming ET around RT would be most effective for maximizing adaptations concurrently.

Aside from chronic overreaching, some researchers have put forth an “acute hypothesis,” which contends that residual fatigue from the endurance component of CT compromises the ability to develop muscular tension during the RT component (16). According to this theory, the tension generated by the working musculature during RT would not be sufficient enough to maximize strength development (16). In addition, proponents of this theory have suggested that performing RT directly preceding ET can alter endurance performance due to residual fatigue (16). Therefore, the acute hypothesis focuses on the scheduling of training sessions as the main interference effect associated with CT, as opposed to simply training concurrently (16).

RT Adaptations

RT adaptations can be broadly described as increases in muscular hypertrophy, strength, and power.

Muscular Hypertrophy: Exercise-induced muscular hypertrophy is centered on the mechanistic or mammalian target of rapamycin (mTor) signaling molecule, which demonstrates increased activity post-RT (20-21). mTor exists in two complexes, but for the purposes of this article we will only focus on mTor1. Increased mTor1 activity results in an increase in protein synthesis through a cascade of intracellular transduction pathways triggered by a mechanical tension/overload stimulus (19). Furthermore, amino acids (specifically leucine) have been shown to increase protein synthesis predominantly by increasing the primary leucine transporter (LAT1), which acts to up-regulate mTor1 (22). Therefore, this would theoretically result in an increase in the cross sectional area (CSA) of the muscle fiber, which directly relates to muscular strength.

Muscular Strength: Muscular strength is a combined effect of neural activation, muscle fiber size, and connective tissue stiffness (2-11). Neural alterations elicited by RT include an increased neural drive, selective activation of motor units (MUs), increased motor unit synchronization, increased rate of force development (RFD), increased inhibition of golgi tendon organs (GTOs) (termed autogenic inhibition), and a reduced antagonist inhibition (2-11, 23). Neural alterations elicited by RT do not appear to be significantly altered by ET, although repeatedly engaging in high-intensity ET could play a role in the milieu associated with neuromuscular fatigue, and/or factor into chronic overreaching (16). Additionally, changes in motor unit recruitment could reduce patters associated with maximal voluntary contractions, which could partially explain reductions in power parameters discussed by Wilson et al (2012) (12, 16). However, these effects should only be considered significant if concurrently training a power sport athlete. Furthermore, there is no research indicating that CT has detrimental effects on connective tissue stiffness, but one could surmise that without chronic overreaching, or an energy deficit, connective tissue stiffness should not be negatively altered by CT.

Muscular Power: Muscular power (force x distance/time) is simply rate of performing work, which can be described as the product of force and velocity. Improvements in muscular power rely primarily on neural alterations, specifically increases in RFD and motor unit synchronization, as well as a reduced antagonist inhibition. A meta-analysis by Wilson et al (2012) suggested that decrements in muscular power may be more likely associated with CT than decrements in either strength or hypertrophy. However, there is a clear dose-response relationship between the volume of ET, and decrements in muscular power (12). Therefore, it can be theorized that individuals wishing to maximize muscular power should limit the volume of ET performed when concurrently training. Furthermore, it can be suggested that performing cycling or rowing for endurance exercise can preserve RT associated adaptations when compared to running (2, 10, 12, 16).

ET Adaptations

ET adaptations can be broadly described as improvements in cardiovascular, muscular, and metabolic function.

Cardiovascular: ET elicits a multitude of cardiovascular adaptations that assist in improving blood flow and delivery. These adaptations include an increase in stroke volume (SV), an increase in heart size (termed cardiac hypertrophy), an increase in cardiac output (due to an increased SV), and a decrease in sub-maximal heart rates for a given intensity. RT has been shown to have a positive impact on exercise capacity (i.e. VO2max) when concurrently training, while initiating a physiological form of cardiac hypertrophy- read more here. These cardiovascular adaptations can have positive impacts on RT training (i.e. work capacity) and recovery, as well as improve cardiac efficiency.

Muscular/Metabolic: ET initiates a variety of adaptations in active skeletal muscle, which include increased mitochondrial volume and density, increased capillary density, and improved fat and glucose oxidation. In addition, there are muscle fiber type transitions that occur as type IIx fibers become more oxidative and resemble type IIa fibers. This muscle fiber transition could theoretically reduce the power output and force per unit of area of the muscle fiber, since myosin heavy chain isoform content of type IIx – IIa – I muscle fibers differ considerably, and have been correlated with various strength indices (16). However, current literature investigating CT has reported little difference in fiber type change between the CT groups and the RT only groups (16). RT training that results in an increase in muscular hypertrophy can blunt the increased capillary density, or decrease capillary density through the increase in CSA. However, unless you are a competitive endurance athlete this should not be a concern. This result can be negated by focusing on high-intensity, low volume RT with loads >85% 1RM (2-11).

The metabolic and hormonal signals initiated during ET turn on certain signaling proteins in skeletal muscle that lead to the aforementioned adaptations. ET involves repeated muscle contractions, which repeatedly releases calcium following each muscular contraction. This calcium activates the calcium-calmodulin kinase (CaMK) family of proteins, which is CaMKII in skeletal muscle (24). Active CaMK can increase the capacity for glucose uptake through the upregulation of the glucose transporter GLUT4, as well as increase mitochondrial volume by transcriptional upregulation of peroxisome proliferator-activated receptor-y coactivator 1a (PGC-1a), which serves as the mitochondrial biogensis regulator (25). With high-intensity endurance exercise there is a decrease of ATP and glycogen, which consequently increases ADP and AMP concentrations. This activates AMPK- activated protein kinase (AMPK), which facilitates an increase in fat oxidation during exercise, while also playing a role in the long-term regulation of mitochondrial volume (19).

In addition, the decrease in glycogen activates the 38 kDa mitogen-activated protein kinase (p38), which can increase the activity of PGC-1a (26-27). Through the rise of lactate and NAD+, there is the activation of the NAD+ dependent deacetylase family of sirtuins (SIRT) (26-27). Members of the SIRT family control the metabolic influx through the tricarboxylic acid (TCA) cycle, insulin sensitivity, and PGC-1a activity (26-27). There is speculation that one or more of these metabolic signaling pathways inhibit mTorc activation and limit hypertrophy when concurrently training, however there is more research needed (19).

There are certain mechanisms by which lactate removal, and ultimately the lactate concentration at a given exercise intensity, could be improved in endurance athletes through a RT program, however it is by no means fully conclusive. Hoff et al (1999) demonstrated improved short-term performance and improved work efficiency in cross-country skiers after a concurrent RT/ET program. Hoff and her colleagues observed a training-induced increase in RFD, which would allow for a shorter propulsion phase for a given overall power (9). This shorter propulsion phase would facilitate an extended muscle relaxation phase, which would reduce the time of contraction-induced muscle occlusion, and hence increase the time of muscle perfusion given the prolonged relaxation phase. This increase time for muscle perfusion would increase the mean capillary transit time (MCTT), which could ultimately allow for an increased MCTT every stride/revolution of an endurance event (9).

Hoff and her colleagues have suggested that due to the relatively large size of free fatty acids (FFA), the increased MCTT could enable an increased diffusion of FFAs into the muscle cells (9). This increased diffusion of FFAs could be described as glycogen sparing, which has been suggested to delay muscle fatigue through a reduced production of lactate (2). Furthermore, an increased MCTT could lead to an enhanced removal of metabolites produced by the contracting skeletal muscle, which could potentially delay fatigue and improve efficiency of the contracting muscle.


Practical Recommendations

  1. Use ET wisely, and strategically program it into your RT blocks. Intersperse HIIT and low-to-moderate intensity ET to keep ET volume at a minimum, while reaping the benefits of ET.
  2. Use low-to-moderate intensity ET (40-60% HRR) as a therapeutic tool to enhance recovery and improve mood state.
  3. Perform ET on a cycle or rower when available. This will reduce the exercise-induced muscle damage associated with running, which has a significant eccentric component. Cycling will also reduce the caloric expenditure since you are activating less musculature than with running, if you are struggling to maintain energy balance.
  4. Alternate between RT and ET “volume focused” weeks with ET frequency no greater than 3 days per week and duration no longer than 30 minutes.
  5. Any high-intensity ET should be performed early in the day, if engaging in RT and ET on the same day. After the morning ET, there should be a recovery period of at least 3 hours to allow AMPK and SIRT1 activity to return to baseline.
  6. RT should be performed in a fed-state, while being supported by a leucine-rich protein source immediately following RT. If performing RT and ET on the same day, it is suggested that a protein-rich source be consumed immediately before bedtime as well.
  7. If performing ET and RT on the same day, you must fully refuel between the morning high-intensity ET session and the afternoon RT session. This will ensure that muscle glycogen levels are restored, while not activating AMPK or SIRT1 activity.
  8. Low intensity, non-depleting ET can be performed before RT, which can provide an improvement in the ET response as well as improve the strength response during RT. However, the key is that the ET must be low intensity and non-depleting.
  9. Program your ET volume around your RT volume. In other words, if you are having a high volume RT week, you should lower your ET volume to compensate for that excess muscle damage and metabolic stress.
  10. Focus on maintaining energy balance! When concurrently training, you need to strive to replace the calories that you are burning. If you train in a caloric deficit, this will undoubtedly compromise your gains in muscular strength and hypertrophy.

Wrapping Up

CT can improve endurance performance through improving work efficiency and increasing anaerobic capacity. There is no literature indicating that CT is detrimental to any performance outcome associated with ET. In contrast, the literature indicates that there is a sharp dose-response relationship with ET frequency and duration (i.e. volume) on RT associated outcomes such as muscular strength, power, and hypertrophy. Therefore, strategically implementing ET based on the current scientific literature will assist in developing an optimal program for maximizing benefits associated with RT and ET, respectively. In addition, there are benefits from low, moderate, and high intensity ET that are maximized by performing ET at a variety of intensity levels. Therefore, interspersing low-to-moderate intensity ET with high intensity ET is crucial, as well as utilizing the current literature to program these strategically.

About the Author


Marc Lewis M.S.(c), CSCS, ACSM-CPT is a graduate teaching/research assistant in the Department of Exercise Science at the University of South Carolina and the Director of Sports Performance for Winston Salem Personal Training.

Twitter: @mtlewis14

Personal Training:



  1. Hickson RC. Interference of strength development by simultaneously training for strength and endurance. European Journal of Applied Physiology. 45: 255-263, 1980.
  2. Aagaard P and Anderson J. Effects of strength training on endurance capacity in top-level endurance athletes. Scandinavian Journal of Medicine & Science in Sports. 20(2): 39-47, 2010.
  3. Hoff J, Gran A, and Helgerud J. Maximal strength training improves aerobic endurance performance. Scandinavian Journal of Medicine & Science in Sports. 12: 288-295, 2002.
  4. Millet GP, Jaouen B, Borrani F, and Candau R. Effects of concurrent endurance and strength training on running economy and VO2 kinetics. Medicine & Science in Sports & Exericse. 34(8): 1351-1359, 2002.
  5. Mikkola J, Rusko H, Nummela A, Pollari T, and Hakkinen K. Concurrent endurance and explosive type strength training improves neuromuscular and anaerobic characteristics in young distance runners. International Journal of Sports Medicine. 28: 602-611, 2007.
  6. Lanao-Esteve J, Rhea MR, Fleck SJ, and Lucia A. Running-specific, periodized strength training attenuates loss of stride length during intense endurance running. Journal of Strength and Conditioning Research. 22(4): 1176-1183, 2008.
  7. Mikkola J, Vesterinen V, Taipale R, Capostagno B, Hakkinen K & Nummela A. Effect of resistance training regimens on treadmill running and neuromuscular performance in recreational endurance runners. Journal of Sport Sciences. 29(13): 1359-1371, 2011.
  8. Paavolainen L, Hakkinen K, Hamalainen I, Nummela A & Rusko H. Explosive strength training improves 5-km running time by improving running economy and muscle power. Journal of Applied Physiology. 86: 1527-1533, 1999.
  9. Hoff J, Helgerud J & Wisloff U. Maximal strength training improves work economy in trained female cross-country skiers. Medicine & Science in Sports & Exercise. 31: 870-877, 1999.
  10. Aagaard P, Bennekou M, Larsson B, Anderson J, Olesen J, Crameri R, Magnusson P & Kjaer M. Resistance training leads to altered muscle fiber type composition and enhanced long-term cycling performance in elite competitive cyclists. Medicine & Science in Sports & Exercise. 39(supp. 5): S448-S449, 2007.
  11. Mikkola J, Vesterinen V, Taipale R, Capostagno B, Hakkinen K & Nummela A. Effect of resistance training regimens on treadmill running and neuromuscular performance in recreational endurance runners. Journal of Sports Sciences. 29(13): 1359-1371, 2011.
  12. Wilson JM, Marin PJ, Rhea MR, Wilson SM, Loenneke JP & Anderson JC. Concurrent Training: A meta analysis examining interference of aerobic and resistance exercise. Journal of Strength and Conditioning Research. 2012.
  13. Davis WJ, Wood DT, Andrews RG, Elkind LM & Davis WB. Concurrent training enhances athletes’ strength, muscle endurance, and other measures. Journal of Strength and Conditioning Research. 22(5): 1487-1502, 2008.
  14. DiLorenzo TM, Bargman EP, Stucky-Ropp RS, Brassington GS, Frensch PA & LaFontaine T. Long-term effects of aerobic exercise on psychological outcomes. Preventive Medicine. 28: 75-85, 1999.
  15. King AC, Oman RF, Brassington GS, Bliwise DL & Haskell WL. Moderate-intensity exercise and self-rated quality of sleep in older adults. Journal of the American Medical Association. 277: 32-37, 1997.
  16. Leveritt M, Abernathy PJ, Barry BK & Logan PA. Concurrent strength and endurance training: A review. Sports Medicine. 28(6): 413-427, 1999.
  17. Damasceno MV, Lima-Silva AE, Pasqua LA, Tricoli V, Duarte M, Bishop DJ & Bertuzzi R. Effects of resistance training on neuromuscular characteristics and pacing during 10-km running time trial. European Journal of Applied Physiology. 2015.
  18. Taipale RS, Mikkola J, Salo T, Hokka L, Vesterinen V, Kraemer WJ, Nummela A & Hakkinen K. Mixed maximal and explosive strength training in recreational endurance runners. Journal of Strength and Conditioning Research. 28(3): 689-699, 2014.
  19. Baar K. Using molecular biology to maximize concurrent training. Sports Medicine. 44(suppl 2): S117-S125, 2014.
  20. Baar K & Esser K. Phosphorylation of p70(S6k) correlates with increased skeletal muscle mass following resistance exercise. American Journal of Physiology- Cell Physiology. 276: C120-127, 1999.
  21. MacKenzie MG, Hamilton DL, Murray JT, Taylor PM & Baar K. mVps34 is activated following high-resistance contractions. Journal of Applied Physiology. 587: 253-260, 2009.
  22. Philp A, Hamilton DL & Baar K. Signals mediating skeletal muscle remodeling by resistance exercise: PI3-kinase independent activation of mTORC1. Journal of Applied Physiology. 110: 561-568, 2011.
  23. Behm DG. Neuromuscular implications and applications of resistance training. Journal of Strength and Conditioning Research. 9(4): 264-274, 1995.
  24. Rose AJ, Kiens B & Richter EA. Ca2+ calmodulin-dependent protein kinase expression and signaling in skeletal muscle during exercise. Journal of Applied Physiology. 574: 889-903, 2006.
  25. Akimoto T, Pohnert SC, Li P & et al. Exercise stimulates PGC-1alpha transcription in skeletal muscle through activation of the p38 MAPK pathway. Journal of Biological Chemistry. 280: 19587-19593, 2005.
  26. Schenk S, McCurdy CE, Philp A, Chen MZ, Holliday MJ, Bandyopadhyay GK, Osburn O, Baar K & Olefsky JM. Sirt1 enhances skeletal muscle insulin sensitivity in mice during caloric restriction. Journal of Clinical Investigation. 121: 4281-4288, 2011.
  27. Rodgers JT, Lerin C, Haas W, Gygi SP, Spiegelman BM & Puigserver P. Nutrient control of glucose homeostasis through a complex of PGC-1alpha and SIRT1. Nature. 434: 113-118, 2005.

How I Became A National Level Olympic Weightlifter In A Year


Biography: Erin Parker is the founder of Spitfire Athlete, a women’s strength training app that teaches you how to lift weights, and that stands for the pursuit of greatness & badassery. Spitfire Athlete is made by two female engineers who are also competitive weightlifters. Erin is a software engineer, Stanford graduate, and 48kg olympic weightlifter.

Download Spitfire Athlete:






I am a weightlifter. I say it with pride. You might not believe it when you see me, because I’m a 4’11” 105lbs woman, and my physique isn’t compatible with most people’s image of a weightlifter. But I am strong and have accomplished a number of physical feats, like lifting over twice my bodyweight, winning a 10,000 push-ups competition (it took me a year), and running multiple marathons.

I started lifting weights entirely for aesthetic reasons. I was phasing out my marathon training, wanted to learn how to squat, and was obsessed with sculpting a six pack, having toned legs, and huge glutes.

“Why didn’t anyone ever tell me this was so effective?” I thought. At the time, I was following Jen Rankin’s Muscle Building Program on Bodybuilding, eating a picture-perfect oatmeal, egg whites, chicken breast diet, and seeing fantastic results. I felt empowered to know that now I have the knowledge and discipline sculpt my body however I like, and I was happily training away at the gym for months.

July 2013: Me taking a progress picture selfie.


Along the way I discovered Bret Contreras and Kellie Davis’s Strong Curves Book. I wanted to improve my glutes and started incorporating hip thrusts and glute bridges religiously into my routine. And then something interesting happened. I was getting pretty good at heavy glute bridges. So, I got into a small competition with myself to lift more and more on the glute bridges.

I started glute bridging around 85lbs, and would add 5lbs each training day. I didn’t realize at the time that I was basically doing a linear progression, but in a few months, I found myself glute bridging a PR of 205lbs at 90lbs bodyweight, and I realized…I am strong. If I can lift over twice my bodyweight in this way, then I must be physically capable of lifting way more than I realize and doing more advanced exercises.

July 2013: My barbell glute bridge PR of 205lbs for reps!


Shortly thereafter, my gym started offering free personal training sessions members who haven’t previously purchased sessions, and I decided this was a great opportunity to learn the snatch and the clean and jerk, exercises which I viewed as advanced at the time, and which I was ready to incorporate into my routine. I didn’t realize that these exercises were part of the sport of olympic weightlifting. I just thought they looked cool. I also didn’t realize that this session would change my trajectory from casual fitness buff to seriously competitive athlete.

My trainer was Larry, a trainer who happened to be a competitive weightlifter and who was previously a competitive powerlifter.

“I see you around the gym a lot,” he said. “You seem to know what you’re doing. Can you tell me more about how I can help?”

“Can you teach me to clean and jerk and to snatch with a barbell?” I asked.

His eyes brightened up. “You want to learn the snatch and the clean and jerk? I can definitely teach the snatch and the clean and jerk. Ok, let’s go. Let’s see what you can do.”

Larry was very passionate about these lifts, and I was lucky to meet him, because he has been one of the most supportive people who would later encourage me to go after bigger goals and who I would see at many upcoming weightlifting competitions. He was the first person who saw and believed that I could be good in this sport.

My first clean and jerks and my first snatches weren’t pretty, but I got the gist of it, and best of all, they were incredibly fun! I felt like such a badass. At the end of the session he said, “Hey, there’s a weightlifting competition in 2 weeks. Want to do it?”

I didn’t even know weightlifting was a sport. I knew about powerlifting…but this was different. This was the snatch and the clean and jerk. Since they were the most badass feeling exercises I had ever done, I decided…I would do it. It couldn’t be harder than a marathon, right?

Two weeks flew by and I was ready as could be for my first competition. In a weightlifting competition, you have three attempts at the snatch and three attempts at the clean and jerk. Your best snatch and your best clean and jerk count towards your total. The lifter with the highest total in their weight class wins. You compete against weightlifters in your weight class, and for women, weight classes range from 48kg to 75kg+. I currently compete in the 48kg weight class.

The competition went really well, and I had a blast. Walk up to the platform and lift heavy shit? I’m all down for that and I would do it again. I even got more excited about the sport of weightlifting after doing some initial research and learning that elite weightlifters in my weight class are actually around my height.

For example, Wang Mingjuan, a badass 48kg Chinese weightlifter who won gold at the 2012 olympics is 4’11”. Hiromi Miyake is a 48kg Japanese weightlifter who won silver at the 2012 olympics and she is 4’9”. In weightlifting, you actually have an advantage if you are short and have shorter limb length proportions because you don’t have to carry the barbell as high to complete the lift.

Here is a chart from Bob Takano’s Weightlifting Programming book showing height ranges for female weightlifters as part of Leslie Musser’s Master Thesis, pulled from the competitors at the 2009 Pan American Weightlifting Championships.


When I noticed that in the 48kg class the minimum height was 4’6”, the maximum 5’0” and the mean 4’10”, it surprised me that my height was in this range! I had the misconception that all weightlifters were tall. This data gave me extra fuel and motivation to participate and compete. I no longer had this fear of being the only small person in the room. There is a weight class for me. I felt like I could belong.

October 2013: Me at my first weightlifting competition.


Here is a video of me at my very first weightlifting meet, hitting a PR of 45kg on the clean and jerk:

My first competition was a wonderful experience. I thoroughly enjoyed it and believed I could be good at it. I liked that my training consistently reinforced the feeling that I was strong and very physically capable.

Here is me at my second weightlifting competition, in January of 2014 (about 3 months later) hitting my then all-time snatch PR of 35kgs:

After testing the waters with a couple competitions, and on a beginner’s high, I decided to get serious and set an aggressive goal. After competing and beating personal bests, I could no longer be happy training the way I used to train. I was hungry. I wanted to be great at something, and I believed this was a sport where I actually have a shot at being great.

I joined a weightlifting team and started working with Coach Bram McArthur of SF Iron. He is both a weightlifting and a powerlifting coach who starts all of his athletes with a linear strength progression of squatting, deadlifting, benching, and overhead pressing. Upfront, I told him my goal was to qualify for a national level competition that year, either USA Nationals or the American Open. At the time, Nationals had a 109kg total to qualify and the Open had a 101kg total. My last meet total was 86kg at the time, so I would have to at least lift an additional 15kg, but I was sure that with hard work and consistency I could get there.

To see how well I was progressing relative to performance benchmarks, let’s look at this Weightlifter Classification System (developed in Eastern Europe), from Bob Takano’s Weightlifting Programming Book. There are six levels in ascending order, Class 3, Class 2, Class 1, Candidate for Master of Sport, Master of Sport, and International Master of Sport.


Here is my competition trajectory:

– First competition on October 2013: Sn 25kg, C&J 45kg, total 70kg (Class 3)

– Second competition on January 2014: Sn 35kg, C&J 51kg, total 86kg (Class 2)

– Third competition on March 2014: Sn 43kg, C&J 57kg, total 100kg (Class 1)

– Fourth competition on April 2014: Sn 44kg, C&J 60kg, total 104kg (Class 1) & Qualified for American Open

– Fifth competition on August 2014: Sn 40kg, C&J 55kg, total 95kg

– Sixth competition – American Open – on December 2014: Sn 44kg, C&J 53kg, total 97kg

Like all the athletes who train with Coach Bram, I started with my first linear strength progression, squatting, benching, overhead pressing, and deadlifting three days a week and increasing weights linearly each week. “We need to put some strength on you,” Bram would say…and yeah, he still says this!

After a few months, I couldn’t believe how much I was lifting. Relative to my bodyweight, it was a lot, although relative to competitive weightlifters, my strength numbers aren’t that impressive.

Today, I believe that we all should go through a linear progression at some point in our lives. Regardless of gender, regardless of whether you’re training for health, strength, endurance, or aesthetic reasons, I believe you should go through an LP, because it will make your body stronger, and you will perform better at everything. Of course, there are sports like gymnastics where the athletes don’t lift weights, so in those cases do what your coach says, but if you’re a recreational athlete, a basic LP done in your “off season” to build strength, can transform your body’s ability to move and perform. It’s also really eye opening to see how strong you are in a short period of time. Each training day, you’re lifting more than you ever have before, basically pushing your limits each time. You can literally feel yourself getting stronger.

My numbers when I started:

  • Squat 1RM 140lbs
  • Deadlift 1×5 140lbs

My numbers after my first LP:

  • Squat 1RM 190lbs (1.9x bodyweight)
  • Deadlift 1×5 210lbs (2.1x bodyweight)
  • Bench Press 1RM 90lbs
  • Overhead Press 1RM 80lbs

I had gained 10lbs of bodyweight, so I hit these numbers weighing around 100lbs. Since I was entered the sport weighing 90lbs, I needed to build up to my competition weight at 105lbs, which I had never ever weighed before. In the sport of weightlifting, you want to weigh as close to your weight class as possible, and since I was 15lbs under the lightest weight class, I needed to gain weight to be competitive.

My first linear progression was over, and sure enough, the gains came! Soon after I hit a snatch PR of 45kg. Moving up to the yellow 15kg plates on the snatch felt huge!

45kg Snatch PR:

I competed at the Hassle Free Open and made a competition total of 100kgs, up 14kgs from my last meet.

Here are my lifts from the Hassle Free Open:

43kg Snatch:

57kg Clean and Jerk:

I was 1kg short of qualifying for any national level meets, so I continued my training and a month later, I tried again. I was training 3-4 days per week and my training consisted mostly of snatches, clean and jerks, and squats.

At my next competition, I made a 104kg total, and qualified for the American Open! I graduated to being a “Class 1” lifter now!

Here are all my lifts from the CTS Wine Country Classic in April 2014, where I made a 104kg qualifying total:

I could have stopped there and just focused on the American Open, but being the aggressive, ambitious go-getter I am, I decided to try to qualify for nationals. I was only 5kgs away from the qualifying total. USA Weightlifting even sent me this really nice email to encourage me to go for it, which I appreciated, even though it’s likely automated. :)


So what was next? I had finished my first LP, transferred those gains to my olympic lifts, and added 14kg to my total. I almost made my last snatch and my last clean and jerk (which would have given me the total needed for nationals) but missed by a very close margin.

For my next competition, I needed to continue practicing the olympic lifts with heavy weights, but I also needed to continue making strength gains. So my coach progressed me to an intermediate program, the Texas Method for weightlifters. This type of program is appropriate for an intermediate strength athlete and relative beginner in weightlifting. The focus is to keep driving the strength of the lifter while sufficiently practicing the olympic lifts.

My program looked like this:


Goal: Practice the olympic lifts.

Sn 2×4-8

C&J 1×5-10


Goal: Volume strength work, to drive strength up.

Sq 75% 5×5

Press 75% 5×5

Chins 3×5-8


Goal: Check progress on lifts and overall recovery.

Sn max for day

C&J max for day

F Sq 3×3


Goal: Check progress on strength and overall recovery.

Squat 1×5

Press 1×5

DL 5×1

The volume day was by far the most challenging. I had to do 8 sets of 2 snatches at 90%+ range followed by 15 clean and jerk singles also in the 90%+ range, with a maximum of 1-2 minute rests in between each set.

Here is a video of me doing (aka struggling) through the Texas Method program:

At first I thought, “This is freaking insane! Is it physically possible to make so many lifts at 90%+?” Not only that, I had to increase the weight with each lift, even if I only increased it by half a pound. Practice was long and difficult. I would barely have a chance to catch my breath, I would be dripping sweat, feeling like I barely had it in me to continue…and then I would have to push myself even harder and lift even heavier than my last rep.

My first week, I would miss lifts left and right. When I was “failing all the time” I felt like I didn’t know what I was doing. But I kept on and gave it my all, even if it felt sloppy. Then…something kind of magical happened. After about a week or two of training at this level, my body adapted. And so did my mind. I suddenly started making these snatch double at 90% of my capacity. I also no longer got so tired, mentally, and was able to stay focused through the entire 8 sets of 2. My technique also started improving, probably because of all the practice, and it was an amazing feeling because I started actually making heavy snatches more consistently.

July 18, 2014, A video of me making heavy snatches more consistently:

On my heavy strength days, I found myself squatting 180lbs for doubles…like it’s a totally normal thing. I remember sharing a squat rack with a guy when I was at a commercial gym once. I had to do something like 185lbs for a double. He was squatting around 135lbs, and when I started warming up into the 150s, 160s, he started trying to squat way outside of his comfort zone just to try and keep up with me. Why? I have no idea. And then he started really struggling at 165lbs. When I finally did my last warm-up at 175lbs and my work set at 185lbs he said, “Oh my god. I can’t even keep up with you.” He was flabbergasted. I laughed and thought to myself, “Of course you can’t!” 😉

I competed in the Tommy Kono Open that summer. It was my worst competition ever for two reasons: 1) I had to cut weight for the first time and 2) I was a complete nervous wreck. I was very care free with my diet in the months before, using my hard training as an excuse to go all out, and now I was well over my weight class. Darn.

Cutting for the first time was tough because I felt extremely energy-deprived and like there was nothing in my muscles. On top of that, I was a nervous wreck because in my mind, this meet was a really important competition and I didn’t want to fuck it up. I wanted to qualify for nationals. This was my last chance! But I was so nervous that I was basically hyperventilating in the warm-up room and I felt like my heart was going to explode out of my chest. In my mind, I kept worrying, “Oh my god what if I fail my opener? What if I don’t make the total? All my hard work will be wasted!”

I even missed my 35kg warm-up snatch. My coach immediately knew something (more like, a lot of things) were really off. Because of the cut and my mindset at the time, the bar felt really heavy, when it shouldn’t have. I only made my opening snatch and my opening clean and jerk. Even though I ended up medaling at the meet, I didn’t make the total I had wanted, and felt like a failure.

Here is what I learned: First, I want to resume having a great diet and stay close to my weight class, not go over too much, and avoid drastic weight cuts. Second, I want to get my mental game together. I want to learn how to not be panicking on the day of competition, and to stay calm, composed, and ready to perform.

A lot of things happened in the next five months after this meet and before the American Open. My start-up, Spitfire Athlete, received investor funding from one of the top accelerators in the country and my co-founder and I flew over to Boston for three months to aggressively grow and build the company.

We had an aggressive schedule, where I had meetings all morning and would code all night, and work with my co-founder towards shipping an app update every week. We didn’t even lift for the first couple of weeks of the program, because things were so crazy and we were barely sleeping.

When our schedule calmed down just a little bit, we managed to get some time to lift at the MIT gym, basically the only affordable gym in the area that we could reach via public transport that had a platform, olympic bars, and bumper plates. But I really struggled. After not lifting for a few weeks, my technique was all over the place, knees caving in, pressing out, and I felt so weak. I completely deprioritized my health, nutrition, sleep, and weight training in order to hit aggressive goals. I remember lifting on days where we only had 6 hours of sleep and where I struggled to make a 40kg snatch.

I reasoned that “this was only going to be for three months, I’ll gain everything back when I’m back in San Francisco” but I didn’t realize it would take months to gain back strength that I had lost in a few weeks. If I were to do it again, I would take the more long term approach and better balance my training with more focused company milestones (because really, we didn’t have to do it all, we just really wanted to).

Nov 2014: Me and my co-founder in Boston, celebrating Spitfire Athlete’s 1 year anniversary. Two women on a mission to make strength training a part of every woman’s routine.


As Techstars came to an end, we had achieved some very meaningful goals, like our 50,000+ users worldwide, hitting our engagement goals (did you know that most workouts tracked on our app are over an hour long?) and ranking in the top 10 for App Store search results like “women’s fitness” and “women’s strength”. We had the most fun pitching to a theatre full of investors and ending our presentation with a clean and jerk. When we talk about badassery, we mean it.



It was close to the end of November 2014. I was back in San Francisco, and training at my coach’s shiny new gym, SF Iron. Squat racks, platforms, and barbells for all! The American Open was in less than one month! My coach advised me to start visualizing having successful lifts. He recommended visualizing me getting nervous, and then controlling my nerves and then executing the lifts well. I did some additional research on the subject of athletic performance visualization and found a book called 10 Minute Mental Toughness.

I read it and decided to give it a try. I would meditate every day, either first thing in the morning or right before practice.

In the first part of the meditation, I would start by taking a deep centering breath. Then, I repeat my performance statements to myself. Here is part of my performance statement: “I have what it takes. Today, I am going to give it my all. I am going to give it every single fiber of my being. I am going to finish strong.”

I would repeat this to myself until I started believing it. And then I would imagine myself at the American Open and getting ready to make my opening snatch. I would imagine feeling nervous, seeing the loaded barbell on the platform, and then imagining myself taking a deep breath, clutching the barbell in my hook grip, and then in slow mo, making the lift. I would imagine myself smiling and the audience cheering at the end of the lift. I do this three times for the snatch, three times for the clean and jerk, imagining myself making the lifts, no matter what. I would imagine myself pushing through and finishing strong on the jerk.

I finished by reciting my entire performance statement again, and then taking a few deep breaths, and then I was out.

I did this meditation every day in the weeks leading up to the competition. I started noticing that it also had an immediate effect on my confidence in practice. Within the first week of doing this, I already started making more of my heavy lifts, particularly my heavy snatches which is what I was the most afraid of.

Now that I was actually visualizing making these snatches more than I was visualizing failing these snatches, I actually started making them! It was quite eye opening, actually, to realize that in the past I was actually visualizing failure more than I was visualizing success.

Before I knew it, I was on a plane and flying off to Washington DC for the American Open, my first national level competition! Since I had recently gotten back from Boston, my strength numbers felt nowhere near where they were earlier in the year, so my focus for this competition was to give it my best mental game and to make my openers. Anything after my openers was icing on the cake.


On the day of the meet, I was up at 6:45am, ready to weigh in by 7am. Yes, I was very nervous. But I think the meditation practice really did pay off, because I wasn’t a complete nervous wreck, and my focus was on making my lifts, and nothing else. Mentally, I was unshaken. Yes, I could still feel my heart beating hard, and my breathing was a little fast, but I kept a focused look on my face and I knew I was going to make it through without panicking.

I made my opening snatch – easy. It felt GREAT. It felt light. I felt strong. Then, I made a 44kg snatch and it also felt solid. I could even hear my mom and my grandma cheering me on from the audience. This was their first time ever seeing me lift!

After my snatches were over, I felt a huge sense of relief. I had gotten over the scariest part of the meet! I thought, “Wow. I was able to get control over my nerves and perform when it mattered.”

Although I finished all my 3 clean and jerks, the judges only counted the first one. My last two were disqualified for press-out, unfortunately. However, it was, by far, my best performance ever, because my mind was in the right place. I felt fantastic. I was cool, composed, and when I did my lifts, I felt confident.

One of my favorite parts of going to this meet was getting photographed by Hookgrip. I had dreamt of getting photographed by Hookgrip one day, and here it was!



I’m excited to continue onward with this journey and to push myself year by year. I love this sport and can’t describe how much fun I have.

As I write this, since the American Open, I have achieved new PRs, namely, a 50kg snatch (hell yeah for the beyond bodyweight snatch), a 63kg clean and jerk, and 78kg front squat. If you go back to the chart from earlier, this in-practice total would allow me to graduate from “Class 1″ and make it to “Candidate for Master of Sport”. Now I just got to take this performance to my next competition.

What’s next? Well, this year, I’m going to try to qualify for Nationals and the American Open again, although this time the qualifying totals have increased to 133kg and 123kg, respectively, so I’ve got to keep on training, working hard, giving it my all.

I feel stronger than ever. If you’re thinking about competing in the sport of weightlifting, I say go for it! Give it a try. You’ll never know, you just might fall in love with feeling like badass every day and never go back.

I’ll end this with one of my favorite quotes by Mia Hamm: “Somewhere behind the athlete you’ve become and the hours of practice and the coaches who have pushed you is a little girl who fell in love with the game and never looked back… play for her.”


Cardio & Appetite: Does Cardio Make You Fat?

Cardio & Appetite: Does Cardio Make You Fat?
By Fredrik Tonstad Vårvik

Does endurance-training (cardio) increase or decrease your appetite? What about resistance training?

Some might say that exercise increases appetite, while others say the opposite. The plain truth is that since exercise burns calories, you should think appetite increases to make up for those burned calories. For those who want to lose weight, that might come as a shock. What sounds logical is not always true. The media have done a great job of convincing the public that exercise increases your appetite and that you end up eating more and getting fat.

I have read and looked into the latest reviews and meta-analysis, which should sum up nicely what we know to date. The research that has been done is mostly short-term. The authors of the studies admit some limitations of the studies – mainly sub-optimal study design and small sample sizes.


Short term

A meta-analysis by Schubert et al, 2013, looked at acute energy intake up to a maximum of 24 hours post-exercise (1). Twenty-nine studies, consisting of 51 trials were included. Exercise duration ranged from 30 – 120 min at intensities of 36-81% VO2max. Test meals were offered 0-2 hours post-exercise. If subsequent meals were presented, they were 4-5 hours apart, from 1-4 meals. The overall results suggest that exercise is effective in producing a short-term energy deficit. Meaning that the subjects did not compensate for the energy they expended during exercise, in the 2-14 hours after exercise. Forty-five studies reported relative energy intake after exercise. They showed that participants compensated for the energy used in exercise by around 14%. All trials reported absolute energy intake. Despite large energy expenditures, the absolute energy intake was only slight higher in the exercise group compared to the no-exercise group, with a mean increase of about 50kcal.

These results are in line with a review of Deighton et al 2014 (2). Namely, that an acute bout of exercise does not stimulate any compensatory increases in appetite and energy intake on the day of exercise.

Short and long term

A review by Donnelly et al 2014, included 103 studies in their review (3). The study design included cross-sectional- , acute/short-term- , non-randomized- and randomized-studies. Exercise duration ranged from a single 30-min exercise bout to daily exercise over 14 days. Energy intake was measured from once post-exercise up to 72 weeks. Overall, the energy intake was reduced in participants doing exercise compared with participants not doing exercise. As noted by the authors: “our results from both acute and short-term trials suggest that any observed increase in post-exercise energy intake only partially compensates for the energy expended during exercise. Thus, in the short-term, exercise results in a negative energy balance.”

As for long term, only 2 out of the 36 non-randomized and randomized trials, in duration from 3 to 72 weeks, reported an increase in absolute energy intake in response to exercise. Moreover, 30 of the studies reported no change in calorie intake, while five of the randomized studied reported significant decreases of 200-500 calories per day in response to training.

Blundell et al, 2015, agrees that exercise has little effect on energy intake within a single day (4). However, in the long-term, there seems to be a raise in compensatory energy intake, ranging from 0 % to 60 % compensation in energy intake for the exercise expenditure.

Low, medium & high fitness level

The meta-analysis by Schubert et al, 2013, indicated that individuals of low and moderate fitness reduce energy intake more than those with high fitness level (1). They reference previous work that agrees that individual who are more physically active more accurately regulate their energy expenditure. The researchers write that active individuals compensate for about 23% of energy expended while inactive individuals actually had a negative compensation of -35,5%. In Donnelly et al’s review, they found no difference in fitness level and energy intake (3).

Resistance training:

Five interventions in Schubert et al’s meta-analysis utilized resistance training (1). The sessions were between 35-90min with 10-12 repetition maximum and 2-4 sets. Acute energy intake up to 14 hours were reduced compared to energy expenditure; however, it was not as reduced as the groups with endurance training. Worth noting is that energy expenditure of resistance training is difficult to quantify precisely. So don’t stop doing resistance training, there are a lot of other positive advantages, like improved body composition. In addition, the review by Donnelly et al found no difference between energy intake post-exercise in endurance exercise and resistance training (3).

Intensity & duration

An effect of exercise intensity was not found in Schubert et at’s meta-analysis (1). However, the researchers mention in the text that others have found that intensities above 70% VO2max appears to reduce appetite but with minor changes in absolute energy intake. In contrast to this finding, Donnelly’s review found no significant difference in exercise intensity and duration on energy intake (3). Deighton et al also concludes that high-intensity does not reduce appetite more than low-intensity (2). However, if you look more into the studies analyzed in Donnelly’s review you will see that high-intensity might have some advantages concerning reducing energy intake.

Compensators & responders

The mean (average) in Schubert et al’s meta-analysis showed a short-term reduction in energy intake (1). However, some actually increased their absolute energy intake post-exercise. Some of the trials in Donnelly et al’s review also increased their energy intake, meaning that some compensate more after the energy deficit the exercise gives (3). Compensators have showed an increase in hedonic response to food, which means they are more sensitive and “weak” to food that give more pleasure eating.

How does exercise influence appetite?

As stated in the start of this article – since you burn calories through exercise you should expect to increase appetite and make up for it with eating more. As the research says, in most people it does not.

The reason might be because exercise suppresses ghrelin levels (a hormone that stimulates energy intake), while increasing hormones that increase satiety, such as peptide YY (PYY) and glucagon-like-peptide 1 (GLP-1) (1). This is in line with data from Blundell et al, 2015, which means that increased physical activity improves satiety signaling and appetite control. And that this system gets deregulated in sedentary people, thereby permitting overconsumption, as shown in the illustration (4).


Exercise does also make adjustments other than with gastrointestinal hormone response and gastric emptying: blood flow, muscle cellular metabolism, adipose tissue biochemistry as well as brain activity gets adjusted by exercise.

Why do individuals lose less weight than would be expected during long-term exercise interventions?

Several theories exist regarding why individuals do not lose as much weight as expected during an exercise program (1).

  • Some might change their dietary intake in response to exercise, especially the compensators
  • Some prefer sweet and high-fat food post-exercise
  • Energy intake may not increase per se, but rather a compensation of physical activity outside the exercise program decreases
  • The research mentioned in this article, stated that there is a highly individual difference between how much you compensate with energy intake, if you compensate much you will see little difference in weight

The bottom line is, on average, exercise will not make you eat more. Moreover, exercise is a tool you can use for losing weight. Energy expenditure of exercise is the strongest predictor of fat loss during an exercise program, according to Deighton et al (2).

Author bio

Fredrik Tonstad Vårvik is a personal trainer & nutritionist. He writes articles and work with online coaching at fredfitology. Follow him and his colleagues at facebook & twitter. Check out FredFitology for more info.



  1. Schubert MM, Desbrow B, Sabapathy S, Leveritt M. Acute exercise and subsequent energy intake. A meta-analysis. Appetite. 2013 Apr;63:92–104. LINK
  2. Deighton K, Stensel DJ. Creating an acute energy deficit without stimulating compensatory increases in appetite: is there an optimal exercise protocol? Proc Nutr Soc. 2014;73(02):352–8. LINK
  3. Donnelly JE, Herrmann SD, Lambourne K, Szabo AN, Honas JJ, Washburn RA. Does increased exercise or physical activity alter ad-libitum daily energy intake or macronutrient composition in healthy adults? A systematic review. PloS One. 2014;9(1):e83498. LINK
  4. Blundell JE, Gibbons C, Caudwell P, Finlayson G, Hopkins M. Appetite control and energy balance: impact of exercise. Obes Rev Off J Int Assoc Study Obes. 2015 Feb;16 Suppl 1:67–76. LINK