Category Archives: Guest Blogs

5 Things People Need to Stop Overthinking

Below is an excellent guest article from Greg Nuckols. I just finished reading the new eBook that Greg wrote with Omar Isuf (HERE is a link to the eBooks – there are two of them; The Art of Lifting and The Science of Lifting), and though I liked both books, I actually liked The Art of Lifting most. I can’t tell you how impressed I am with Greg and Omar’s insight. I’ve been a big fan of Greg and Omar for a while, so it’s great to see them come out with a great product together.

5 Things People Need to Stop Overthinking
By Greg Nuckols

There are three laws I’ve found to be true in a remarkable number of cases:

  • Parkinson’s law: “Work expands so as to fill the time available for its completion.” If you have a 2 hour project and 8 free hours to work on it, it will generally take you all 8 hours to finish it. Conversely, if you slack until you only have an hour left, you’ll usually end up getting it done, and doing a pretty decent job at it.
  • Poe’s law: “Without a blatant display of humor, it is impossible to create a parody of extremism or fundamentalism that someone won’t mistake for the real thing.” If you’ve ever been sucked into a really long Facebook argument about almost anything (be it training, nutrition, politics, religion, etc.), then you probably understand who this law is referring to.
  • Sayre’s law: “In any dispute the intensity of feeling is inversely proportional to the value of the issues at stake.” This is the law that this article addresses. Little nitpicky things that really don’t influence your results in any meaningful way are almost guaranteed to be the subjects of heated discussions where friendships are ruined, e-dicks are measured, and no one comes out of the discussion any better off for having had it.


  1. Bar position for squats

Let me describe an exercise for you. You place a loaded barbell across your shoulders, squat down to a position with high degrees of both knee and hip flexion, either as deep as you can go, or as deep as you can safely go before your back starts rounding, then stand up.

Did I just describe the high bar or low bar squat? If you guess “both,” you’re absolutely right. Moving the bar 2-3 inches up or down your back doesn’t make enough difference for 99% of people to worry about. Try them both out, and do whichever is the most comfortable for you.

If you’re a powerlifter, then obviously the main criteria to use is: “Which allows me to move the most weight?” That’s the whole point of the sport, after all. If you’re a weightlifter, then high bar is probably prudent since it most closely mimics the position in which you’d receive a clean or snatch.

If you don’t compete in either of those sports, then just squat; bar position really doesn’t matter.

  1. Beltless training

This is another topic that, while not entirely unimportant, is not worth arguing about until you’re blue in the face.

It’s pretty clear that training with a belt allows you to lift heavier loads, doesn’t really affect activation of your abdominal muscles, and may even lead to increased activation of your prime movers due to increased spinal stabilization and the aforementioned heavier loads. It also increases intra-abdominal pressure, which can cause an even larger spike in blood pressure when training, meaning it could be problematic for people who have conditions exacerbated by blood pressure fluctuations.

So if you want to lift as much weight as possible right now, wear a belt. If you have issues that are made worse by blood pressure spikes, then don’t wear a belt.

For training purposes, I’m not aware of any data showing that training with or without a belt really affects strength gains. Plenty of people have gotten strong lifting primarily with a belt, and plenty of people have gotten strong lifting primarily beltless. Just do the one you prefer.


  1. Stance width, footwear, grip width, or deadlift style

If I had a nickel for every time I saw a “guide” to choosing footwear or stance width of squat, grip width for bench press, or deadlifting style (sumo or conventional) based off some arbitrary anthropometric measurements, I’d probably have about $1.00. Meaning there are at least 20 too many in existence (I wrote one of them. Sorry).

When did people forget that they could just experiment? Trying different options isn’t feasible for things that have a high opportunity cost (i.e. buying a house. You can’t narrow it down to two, buy them both, live in both for a while, and then decide which one you like best), but none of the aforementioned decisions have a high opportunity cost. The costliest would be buying an extra set of shoes for squats to see if you prefer squatting with a raised heel or without one (which will be ~$60-70 unless you want to buy top of the line weightlifting shoes).

Want to know what squat stance is best for you? Go to the gym, load up about 70% of your max, and try out a few different stance widths and a few different toe positions. Go with the one that feels the strongest and most comfortable. Ditto for bench press grip width. Ditto for sumo and conventional deadlifts.

The most important research in this area? The N=1 case study you do on yourself that will take maybe 15 minutes.

  1. “What’s the best exercise for…?”

There are a few circumstances where there is a clear-cut best exercise to accomplish a specific purpose. One is when you’re having difficulty learning a complex movement; a slower or regressed version of that movement, or the piece of the movement you’re having the most difficulty with (depending on the situation) is probably the best thing you can do. Or, if you’re trying to master an exercise for its own sake (i.e. if you’re a powerlifter and you want to improve your squat), that precise exercise is probably the best exercise you could do to accomplish that purpose.

Beyond that, it’s wide open. There are no magic exercises. If there’s a general movement pattern you’re trying to improve (not a specific exercise. i.e. pushing strength instead of strictly the bench press), then basically any exercise with similar demands through a fairly long range of motion will do the trick. If there’s a specific muscle you’d like to grow and strengthen, then just about any exercise for which that muscle is likely to be the primary limiting factor will work just fine.

Instead of searching for (or worse, wasting time debating online) some magical exercise, use some critical thinking skills and find movements that look similar to the skill you want to improve, or that overload the muscle you’re trying to grow or strengthen, and do them consistently over time, applying progressive overload. It works like a charm every time.

  1. Size vs. strength

Gaining size (muscle mass) versus gaining strength is really a false dichotomy for most people; they’re two sides to the same coin.

Now, if you’re brand new to lifting, you’ll probably gain strength (weight on the bar) much faster than you gain muscle mass initially. That’s a simple matter of your nervous system learning the movement and figuring out how to effectively use the muscle you currently have (plus a little extra you build) to move the load.

Once you’ve learned a movement, though, there’s only one way to keep those strength numbers ticking up: Those muscle have to grow.

On the other hand, if you’re training primarily to gain mass, those muscle gains will be slow in coming unless you apply progressive overload (increasing training volume, intensity, or both). And, by doing so, you’ll get stronger. Then, with that increased strength, you can load the muscles even heavier, create more tension, and grow bigger yet.

To get stronger (unless you’re a complete beginner), you need to get bigger, and to get bigger you need get stronger. Training for one without the other doesn’t really make sense for most people.

In some fringe cases it may be possible and necessary. For instance, if you’re an elite powerlifter weighing very close to the top of your weight class, then you may need to train in a manner to eek the last possible neural improvements out of the movements without gaining muscle mass that would push you into the next weight class (of course, if you can grow into the next biggest weight class, it would probably be good to do so because you’d be carrying more muscle per unit of height, and probably be more competitive, but that’s another discussion). If you’re a bodybuilder with a long injury history and not much more room for growth in the first place, then avoiding the heavier training that drives strength gains in favor of lighter, more voluminous training may be prudent.

For everyone else, get stronger to get bigger and get bigger to get stronger.

Click HERE to check out Greg’s new eBook

The Art of Lifting

About the Author

GregGreg Nuckols is the owner and founder of, a website dedicated to combining lifting advice with biomechanics and scientific theory. More than 250,000 people visit and learn from Strengtheory articles each month. Greg is also the chief content director at Juggernaut Training Systems, one of the biggest strength websites in the world. As the owner of one large fitness website and the content director of one even larger, Greg is very tapped into what questions people have and what information is often misconstrued. Practicing what he preaches, Greg has held 3 all-time world records in powerlifting. His current numbers are a 755lb. squat, 475lb. bench, and 725lb. deadlift.

Building Multi-Directional Strength and Power

My friend Eric Cressey of Cressey Performance is currently offering $50 off of his High Performance Handbook program until the end of the week. In an effort to help promote his excellent training resource, I asked him to write me a badass guest blog. He definitely didn’t disappoint! I hope you enjoy Eric’s article and videos. 

Building Multi-Directional Strength and Power
By: Eric Cressey

Sagittal-plane dominant exercises like squats, deadlifts, bench presses, and chin-ups get all the love in the world of strength training, but the truth is that both everyday activities and all levels of athletics require individuals to be strong and powerful in both the frontal and transverse planes, too. This knowledge gave rise to a central tenet of the functional training era: multi-planar training.

Unfortunately, it’s just not as simple as telling folks to train in all three planes, as there is a progression one must go through to stay healthy while reaping the benefits of these new exercises.  Otherwise, baseball players (as an example) wouldn’t need hitting and pitching coaches any more than basketball players would need “vertical jump coaches.” Getting outside the sagittal plane is challenging to learn, and complex to train. With that in mind, I thought I’d use today’s post to outline some of my favorite training progressions in this regard. We’ll start with actual “strength movements.”

Building Usable Strength

  1. Single-leg Exercises

To the casual observer to exercise science, single-leg drills are sagittal plane exercises.  However, what you must appreciate is that while you’re training in the sagittal plane, you’re actually stabilizing in the frontal and transverse planes.  It’s important that you master these drills in the sagittal plane before you start experimenting with strength work in the frontal and transverse planes.

In terms of progression, one can start with either dumbbell-at-the-side movements or the goblet position, and then move to scenarios where the center of mass raised by using barbells or holding weights overhead. You could also wrap a band around the lower thigh and pull the knee into adduction/internal rotation to increase the challenge in the frontal and transverse planes.

  1. Alternating Lateral Lunge with Overhead Reach

Also at the basic level, you can work unloaded lateral lunge variations into your warm-up. They might be in place, or alternating. As soon as folks can handle them, though, I like to progress to including an overhead reach in order to challenge anterior core stability and raise the center of mass up away from the base of support a bit.  This also gives folks a chance to work on their shoulder mobility and scapulohumeral rhythm.

Bowler squats are also an awesome exercise to begin to challenge control outside the pure sagittal plane:

  1. Plate-Loaded Slideboard Lateral Lunge

I like this as a starter progression because the plate out in front serves as a great counterbalance to allow folks to work on their hip hinge. Additionally, there isn’t a big deceleration challenge on the leg that’s going through the most abduction range of motion; rather, the load is predominantly on the fixed leg, which is resisting excessive adduction (knee in).

Worthy of note: I never load this beyond 10 pounds, as folks tend to become kyphotic if the counterbalance is too heavy.  You’re better off loading with #3…

  1. Dumbbell or Kettlebell Goblet Slideboard Lateral Lunge

By keeping the weight closer to the axis of rotation (hips) and minimizing the load the arms have to take on, we can load this up a bit without unfavorable compensations.

  1. 1-arm Kettlebell Slideboard Lateral Lunges

This exercise builds on our previous example by adding an element of rotary stability.  You’d hold it in the rack position (or go bottoms-up, if you want variety and an increased stability challenge at the shoulder girdle). I’ve tried this with the KB held on both sides, and it’s a trivial difference in terms of the challenge created – so you can just use rotate them for variety.

  1. Dumbbell (or Kettlebell) Goblet Lateral Lunge

You can load this sucker up pretty well once you’re good at it. Just be cognizant of not getting too rounded over at the upper back.

  1. In-Place Lateral Lunge with Band Overload

This is variation that we use sparingly, but it does always come in handy when you have a post-op elbow or shoulder athlete who can’t hold weights in the affected upper extremity. The band increases eccentric overload in the frontal (and, to a lesser degree, transverse) plane, effectively pulling you “into” the hip.  You have to fight against excessive adduction/internal rotation, and then “get out” of the hip against resistance.  This is something every athlete encounters, whether it’s in rotational power development or basic change-of-direction work.

As an added bonus, using a band actually creates a scenario of accommodating resistance.  Assuming the partner stays in the same position throughout the drill, the tension on the band is lightest when you’re the weakest, and it’s more challenging where you’re stronger.

  1. Side Sled Drags

Side sled drags are a great option for integrating some work outside the sagittal plane for folks who either a) aren’t coordinated enough for lateral lunge variations or b) have some knee or hip issues that don’t handle deceleration stress well.  As you can see, the exercise is pretty much purely concentric.  We’ll usually use it as a third exercise on a lower body strength training day – and as you can see, it can offer some metabolic conditioning benefits as well.

Keep in mind that these are just strength development progressions, and they don’t guarantee that anything will transfer over to aggressive power training in the frontal and transverse planes. That’s where the following exercises come in.

Building Usable Power

  1. 1-leg Rotational Med Ball Taps to Wall and Split-Stance Anti-Rotation Scoop Tosses

These are two med ball exercises you have to dominate before I’ll allow you to go to the next level. The 1-leg rotational med ball tap verifies that you have enough static balance to be able to even train dynamic balance. It’s low-level and can be practiced every day. Every single one of our baseball players does this early on in their programs – and there is actually some research to suggest that static balance proficiency is associated with improved pitching performance.

The split-stance anti-rotation scoop toss is key because it introduces the concept of hip/trunk separation through good thoracic mobility (as opposed to excessive lower back motion).

Additionally it teaches athletes to have a firm front side to help accept force.


  1. Rotational Med Ball Scoop Tosses and Rotational Med Ball Shotputs

These are the two “cornerstones” of any rotational power training program. The “separation” sequencing is comparable for the two, as efficient rotation is efficient rotation. However, what is different between the two is the demands on the upper body. Generally speaking, a scoop toss (when done correctly) will be easier on the elbow and shoulder.

  1. Scoop Toss and Shotput Progressions

The progressions of these two “core” drills is primarly focused on playing with rhythm, tinkering with momentum, and increasing eccentric preloading (respectively).

  1. Lateral Hops

Hops are done on one leg, and jumps are on two legs. However, just to give athletes constant reminders, I always call them 1-leg hops. It’s like saying “side laterals,” but whatever! You’ve got to be able to both produce and reduce force in the frontal plane before taking the next step. I like this drill without a hurdle to start, with a progression to using low hurdles and ultimately a short-response (no pause on the ground between each rep).

  1. Heidens (Skaters)

Named after speed skater Eric Heiden, these are a great way to build on hopping initiatives in the frontal plane. The most important component is to emphasize good hip force production/reduction and appropriate shin angles.

  1. Heiden Progressions

To progress heidens, you can do a few different things:

a. Change landing positions:

b. Add resistance:

c. Minimize ground contact time: just do a regular heiden, but spring back quickly. We call this a reactive heiden.

d. Increase eccentric pre-loading: Step off a low (12”) box, and go directly into a heiden.

  1. Sprint and Agility Drills

You won’t get a greater plyometric training effect – most of which occurs in single-leg stance – than with sprinting at top speeds and doing change-of-direction training. Beyond the carryover you’ll get to power in the frontal and transverse planes, you’ll also reduce the likelihood that an athlete will get injured during the actual “movement” portions of his/her athletic endeavors.


This certainly isn’t an exhaustive list of our strength and power progressions, but it does offer a glimpse into some of the thought processes of how we bring rotational sport athletes along over the course of time. Hopefully you’ve acquired some new exercises and programming strategies you can apply yourself or with the athletes you coach. 

Bret: As you can see, Eric puts a lot of time and energy into creating detailed programs that are both backed by science and molded by anecdotal experience. The High Performance Handbook is one such example, and is a versatile program that can be used to accomplish a variety of different athletic and fitness goals. It’s also on sale this week for $50 off; click here to check it out.


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.


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  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.
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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:



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