Category Archives: Coaching Tips

Why Do People’s Knees Cave Inward When They Squat?

Strength coaches and physical therapists tend to use fancy terminology to describe knee caving in a squat. For example, the terms knee valgus, valgus collapse, and medial knee displacement are tossed around quite frequently. Most strength coaches believe knee caving to be undesirable from a knee health standpoint. Countless greats in S&C circles seem to fall into this camp, including experts ranging from Kelly Starrett, to Louie Simmons, to Dan John, to Mike Boyle, to Mark Rippetoe, to Eric Cressey, to Tony Gentilcore, to Mike Robertson. It is thought that keeping the knees tracking over the toes in the squat will produce the least internal load on the passive knee structures, thereby keeping them healthy. Another champion of the knees out strategy is yours truly. I’ve written articles and filmed plenty of videos on this topic, including THIS one addressing valgus collapse as a whole, THIS one showing a simple squat correction, THIS one discussing coaching cues. Also, THIS guest blog from Derrick Blanton shows another simple correction strategy, and HERE is an article by my colleague Chris Beardsley discussing the mechanisms of knee valgus.

knees in-out

Strength expert and physical therapist Kelly Starrett showing knees-in versus knees-out in a squat


However, over the past couple of years, the “knees out” mantra has been challenged by some highly competent and knowledgeable lifters. For example, HERE is raw powerlifter Dan Green casting doubt on the efficacy of the knees out strategy, and HERE is the Chinese Olympic Weightlifting team’s take on knees out. These folks believe that allowing the knees to come in slightly at the bottom of the squat is safe and produces a stronger squat. A couple of years ago, I coined the term “valgus twitch” to describe the tendency of very strong lifters to utilize a quick “knees in” strategy when emerging out of the hole during squats. You see this all the time with powerlifters and weightlifters.

It should be pointed out that this debate does not apply to beginners. When beginners first learn the squat, the vast majority of them cave inward at the knees. After sufficient practice with sound technique, most lifters are able to regroove their motor patterns and their automatic default squatting technique will shift to a knees out strategy. I would also argue that women tend to cave inward even more so than men. In fact, every single female client I’m currently training battles the tendency to medially displace their knees when squatting. Knee caving is therefore a natural tendency of human movement. Beginners do it. Women do it. And even some of the most advanced male lifters do it.

However, there is a difference between beginners and advanced lifters regarding knee caving in that beginners will tend to cave inward via a combination of hip adduction, hip internal rotation, tibial external rotation, and foot pronation, and they’ll tend to exhibit this valgus collapse during a more broad portion of the movement. In contrast, more advanced lifters seem to briefly “twitch” into hip adduction when at the bottom of the squat as they initiate the concentric portion of the movement, and they usually revert back to having their knees out after they pass the sticking region.

Then Why Do We Cave?

Recently, Jonnie Candito of Candito Training HQ collaborated with my intern Andrew Vigotsky in order to tackle this question. Please watch the following video for a breakdown of possible factors as to why we might cave inward at the knee during squats. I found myself nodding in agreement throughout the entire video.

My Take – Why Do I Think Strong Lifters Cave?

Many beginners cave inward at the knees during a squat on account of insufficient ankle dorsiflexion range of motion or very poor gluteal strength and development. But we’re not talking about beginners right now. We’re talking about advanced lifters.

If an individual can squat with sound knee mechanics with light loads and keep the knees tracking over the toes, then this means that they do not have a mobility, stability, strength, or coordination problem. Their ankles are not too tight. Their hips are not too tight. The muscles that supinate the feet, invert the ankles, and abduct/externally rotate the hips are strong and stable enough. Some of my powerlifting friends exhibit knee valgus when they’re squatting. Am I supposed to inform them that they have weak glutes when they can squat, deadlift, and hip thrust over 500 lbs and lateral band walk like a boss? Methinks not.

Hi World Record Holder in the Snatch, did you know you had weak glutes?

Hi World Record Holder in the Snatch, are you aware that your glutes are weak? Yeah right.

There has to be some sort of strength advantage to caving inward at the knees, or else we wouldn’t resort to this strategy when maxing out or repping to failure. Since many lifters do in fact do this, we should try our best to understand it.

I have thought about this for many years and I’ve come to the conclusion that there has to be some sort of leverage improvement or lengthening associated with one or more of the hip extensors when the knees are caved inwards. In other words, when the hips are slightly adducted and internally rotated (valgus collapse), one or more of the muscles that extend the hips (the main muscles here are the gluteus maximus, hamstrings, and adductor magnus) would need to be stronger in this position. A muscle can be stronger if it is lengthened to a greater degree, more highly activated, or placed in a position with more favorable leverage (greater internal moment arm).

To my knowledge, there is currently no research investigating the hip extension torque/strength capacity of the various hip extensors at the bottom of the squatting movement in varying degrees of knee varus and valgus (different knee positions). Therefore, I’m unaware as to whether the gluteus maximus, hamstrings, adductor magnus, or hip external rotators are stronger as hip extensors with the knees exhibiting valgus collapse.

Side Note for Sports Science Students: In order to tackle this question, it would require an entire PhD thesis (hint hint aspiring PhD sports science or muscle modelling students). The first study could investigate 3D joint angle movements, EMG, sticking regions, and torque angle curves in the deep squat. The second could investigate hip extension torque in an isokinetic dynamometer with varying degrees of knee varus/valgus and also vertical force production on a force plate during an isometric deep squat with varying degrees of knee varus/valgus. The third could utilize musculoskeletal modelling to estimate moment arms and lengths of all main hip extensors throughout the hip flexion-extension movement continuum in varying degrees of knee varus/valgus. The fourth could be a training study to see if hip strengthening and motor control training improves upon squatting technique with maximum loads and helps eliminate knee valgus. But I digress…

I surmise that the lateral hamstrings (biceps femoris long head) would be stretched to a greater degree in knee valgus, whereas the adductors and possibly the medial hamstrings (semitendinosus and semimembranosus) but not the gluteus maximus or lateral hamstrings (biceps femoris long head) might have greater hip extension moment arms in knee valgus, but this would require research for verificaiton. A recent article published in Clinical Biomechanics with the title, “Lengths of the external hip rotators in mobilized cadavers indicate the quadriceps coxa as a primary abductor and extensor of the flexed hip” indicates that the hip external rotators (namely the piriformis and obturator internus) are in fact strong extensors of the hip, and their length is increased in hip flexion and adduction (meaning that they produce greater passive elastic force at the bottom of a squat, and this is enhanced when the knees are caved inward). Considering that the hips are more heavily relied upon as loads increase in the squat, it makes sense that lifters would resort to mechanical strategies that would enhance the strength of the hips with maximal squat loads.

My current position on the knees out debate is that:

  1. Beginners must learn the rules before they can break the rules and master the knees out technique when squatting
  2. A “valgus twitch” is acceptable for powerlifters and Olympic weightlifters as long as it’s not associated with knee pain
  3. Since many individuals appear to be stronger in slight knee valgus, this indicates that their hip extension torque production is stronger in slight hip adduction and internal rotation
  4. Future research should investigate the hip extension torque capabilities and partition the individual contributors to hip extension torque in deep hip flexion with varying levels of knee varus/valgus

Trust Me, You Have the Time: Fitness Excuses Under Scrutiny

Let’s face it: Life is tough!  Work alone is hard enough, but we also have our daily chores and errands to run, our friendship and familial duties, various hobbies, and emergencies to deal with. In addition, we’re supposed to be trying to get ahead in life, getting sufficient sleep, and maintaining a social life, all while keeping everything in good balance. Now we’re being told to add more onto our plates – exercise – without completely falling apart?

You might be thinking to yourself that you simply do not have the time. Furthermore, you might be looking at all of those fit people out there with disgust. Clearly they starve themselves and are all slaves to the gym. There’s absolutely no way that they can lead normal lives, let alone have any fun, right? You’d like to see them try to look good and be fit while dealing with actual responsibilities and real jobs. They couldn’t possibly juggle half of what you deal with, let alone handle your lousy genetics.

Does any of this sound familiar? I’m sure that almost every person, fit or unfit, has felt this way at some time or another. Life can be damn hard, so it’s no surprise that many people struggle to devote ample time toward their fitness. But I’m here to tell you that you do have the time, you’re not too busy, and you can accomplish more by prioritizing your health and fitness.


You Do Have the Time, You’re Just Not Prioritizing

Of all the fitness excuses, “I don’t have the time” has got to be the most common, and also the most lame. First of all, we all have the same 24 hours in a day, the same 168 hours in a week, the same 730 hours in a month, and the same 8,766 hours in a year. Fit people don’t have 25 hours in a day, and most of them work just as hard as you do. Think hard about it – there are fit people who run multiple businesses and are workaholics, and there are unemployed people who are unfit. Fitness and number of hours spent working are not well correlated. I have many gym friends who work 60+ hours per week and still make it to the gym 4-5 days per week, and I also have friends who work part time and still don’t work out. But this is irrelevant. Even if you were working three jobs, you could still find the time to be fit and healthy. Making exercise a habit has more to do with being motivated, dedicated, determined, familiarized, and confident than it does with having ample free-time.

In the past, I’ve written several articles on training for busy people.

Though many people prioritize their health and fitness and dedicate the appropriate amount of time toward allowing them to be fit and healthy, others do not. Being healthy and fit really don’t require that much time. For most people, all it would take would be to make a few lifestyle adjustments, add in 30 minutes per day of resistance training several times per week, and start making proper food choices.


I don’t think people realize what a dramatic impact this has on one’s physique over time. But there’s a caveat – the training must be progressive in nature. Click HERE for a great article on progressive overload. Let’s say that you’re a total beginner female in weight training, and you can currently perform 20 bodyweight squats, 20 Romanian deadlifts with 45 lbs, 20 bench presses with the 45 lb bar, and 20 lat pulldowns with 50 lbs. Say you increased the load just 10 lbs each month for lower body lifts and 5 lbs each month for upper body lifts and performed the same amount of reps. At the end of year one, you’d be performing 20 reps of squats with 120 lbs, 20 reps of RDLs with 165 lbs, 20 reps of bench press with 105 lbs, and 20 lat pulldowns with 110 lbs. You’d be in pretty good shape at this point in time. Say it takes you two years to reach this level of strength – so what? Each month, you’ll be looking better and getting healthier, which is the whole point of exercising. You just need to get the ball rolling and start making exercise a habit.

The Key Elements to Looking and Staying Fit

What are the key elements to looking and staying fit? I’d say that there are three:

  1. Staying at a bodyweight that allows you to be lean (15% bodyfat for males, 20% bodyfat for females)
  2. Performing rigorous exercise at least a couple of times per week (preferably progressive full body resistance training)
  3. Adhering to a sound nutritional strategy (ideal caloric intake and macronutrient split)

The bodyweight that allows you to be lean is highly influenced by genetics, and of course, height. Ideal bodyfat percentages are subjective. Some people prefer to carry a bit more weight and are okay with 20% bodyfat levels, while other people prefer to stay leaner and maintain 10% bodyfat levels year round. In general, most males will appear fit at 15%, whereas most women will appear fit at 20%. Some genetically gifted males can stay under 15% bodyfat levels while weighing 220 lbs or more, but others have to weigh 170 lbs or less in order to stay under 15%. Over time, with progressive weight training and a slight caloric surplus, you can raise your bodyweight while keeping bodyfat percentage constant by packing on mostly solid muscle. You can also stay the same weight while reducing your bodyfat percentage by gaining strength. But you need to make good nutritional choices in terms of total calories and macronutrient split. Rare is the person who can just eat whatever he or she wants and stay lean, especially once the individual advances past the age of 30.

Once You Get Fit, You Don’t Want to Lose it (Plus it’s Much Easier to Maintain)

Your efforts to be lean will likely be much easier once you attain leanness. Once you’re fit, you won’t want to lose it. You won’t cheat as often or as severely. Training tends to be more fun when you’re familiar with resistance training and highly coordinated. After sufficient training, your muscle cells have many more nuclei (through satellite cell activation caused by resistance training), your hormones and enzymes are working in your favor, and you have more metabolic flexibility. We all have to put in the hard work, but it pays dividends in time.


The 20 Most Common Fitness & Health Excuses

Being busy and not having enough time isn’t the only excuse that crops up in fitness, there are numerous others. Below is a list of common fitness excuses – these are all barriers to success.

1. I don’t have the time (I’m too busy)
2. I don’t want to count calories (I don’t want to weigh my food)
3. I don’t want to avoid my favorite foods (I get cranky if I restrict my carbs)
4. I don’t have the energy (I don’t have the motivation, I’m too tired)
5. I don’t want to be obsessed (I don’t want to be a gym rat)
6. I don’t have a trainer (I don’t know what I’m doing)
7. I don’t get a break from the kids
8. Exercise is boring
9. Exercise is painful
10. I’ve tried before and I never see results (nothing works for me)
11. I’m too old
12. I don’t have a gym membership (there’s no gym nearby, I can’t afford a gym membership)
13. I don’t have anyone to train with
14. I’m too fat
15. I’m already thin
16. I’m too stressed out
17. I’m too insecure (I’m too self-conscious)
18. I don’t really care about my health (it’s not a priority)
19. I’ll start up next month and give it my all
20. I don’t want to get bulky

When you scrutinize these excuses, they’re actually quite silly. I’ll refute all 20 excuses in this paragraph. You do have the time, you just have to find ways to sacrifice, better manage your time, and make exercise a habit and a priority. You don’t have to count calories, but if you do you’ll likely see even better results. You can have carbs and inject some of your favorite foods, no matter how seemingly unhealthy they are, into your diet, as long as it fits your macros. Working out will help cure lethargy and give you more energy throughout your day. Training 3-5 days per week isn’t obsessed, it’s healthy – it’s what everyone should be doing – anyone who claims that that amount of training is obsessive is lazy and pathetic. You don’t need a trainer – if you hire one you’ll likely see better results, but you can learn plenty off of the Internet, from gym members, and from magazines. Resistance training becomes more fun and less boring when you’re fit since you’re performing more advanced exercises and using heavier loads. Exercise isn’t painful if you do it right, and it can help you rid chronic pain if you do it right as well. If you tried it and didn’t see results, you weren’t doing it right – try again. You’re never too old to exercise. You can get an amazing workout from just using your bodyweight and minimal equipment, no gym is required. You don’t need a training partner, but if you try you will likely acquire one in time. If you’re fat, then exercise will expedite your progress, so start now. Being thin doesn’t mean you’re fit – exercise is good for everyone. Exercise is a stress-reliever and the benefits will transfer over to other areas of your life. Exercise will help you develop self-confidence and increase your sense of security. If you care about your friends and family, then you should care about your health for them – they don’t want to see you hospitalized or worse, dead. If you say you’re going to start up next month, then do it – people who are “all talk” are annoying – but you should start today, why wait? And finally, you won’t bulk up unless you eat more – any form of exercise causes you to burn more calories, so as long as you don’t follow it up with greater caloric intake, you’ll either lose or maintain your weight.


If you’re not exercising already, you really should start. It will do wonders for your physical and mental health and fitness. In twelve months, you could be in an entirely different body and mindset. See what a difference one year made for Ruth in THIS article – it will blow your mind. I will end this article with a quote.

Excuses are the tools of the weak and incompetent.
Used to build monuments of nothingness.
Those who excel in it seldom excel in anything else but excuses.

– Anonymous

Considerations for the Rehabilitation of the Post-operative Knee: Restoring the Athlete’s Active Knee Range of Motion

Considerations for the Rehabilitation of the Post-operative Knee: Restoring the Athlete’s Active Knee Range of Motion

Robert A. Panariello MS, PT, ATC, CSCS
Professional Physical Therapy
Professional Athletic Performance Center
New York, New York

During the course of rehabilitation of the post-operative knee pathology athlete, common interventions utilized in the field of Sports Physical Therapy and Rehabilitation include the use of modalities for pain, edema, and neuromuscular control, restoration of the knee joint range of motion, lower extremity strength, proprioception, and normal gait, as well as structured treatment progressions to the achievement of the eventual milestones of running, jumping, cutting, and additional athletic activities, and “functional tasks”. All of these milestones are achieved through a number of various treatment methods, manual techniques, exercises, and practices.

Specific training techniques may also be implemented in the clinical setting that may be more suitable in preparing the post-operative knee athlete for the eventual goal of sprinting/running. Proper running technique will not only result in the ability of the athlete to return to their pre-injury running velocities, but also prepare the athlete to partake in an off-season performance enhancement training program or the return to in-season sports participation and training. The training techniques described in this article are those that have been imparted upon me or those adapted to the clinical setting based on my experiences as a Head Strength and Conditioning (S&C) Coach.

By instrumenting these exercise techniques during the rehabilitation process, empirically I have found (a) the athlete is better prepared to technically return to optimal running velocities as well as (b) upon their return to performance enhancement training it is not necessary for the S&C Professional to instruct the athlete in these exercise techniques as more valuable time may now be utilized for the enhancement of the athlete’s physical qualities as well as advanced running techniques.

Restoring Active Knee Range of Motion 

The concept of restoring full active range of motion (AROM) of the post-surgical knee during the rehabilitation process was instilled upon me approximately 30 years ago by my good friend Dr. Donald Chu. Over the years Dr. Chu, as well as myself, have both lectured and written with regard to this rehabilitation topic. Although there appears to be professional interest in this information, at the conclusion of their rehabilitation many athletes who arrive to our facility to return to their athletic performance enhancement training, still lack the necessary knee AROM for optimal running performance.

AROM of the knee is imperative to achieve the proper positioning of the heel of the foot at (approximately) the level of the gluteal fold during the swing phase of the running gait cycle. The swing phase comprises 30% of the running cycle, thereby it is very important to re-establish proper back side (swing phase) mechanics. Since the sprinting/running gait cycle is truly a “cycle” if one phase of the running cycle is not efficient, the entire cycle becomes inefficient.

The majority of post-operative knee patients achieve full passive knee range of motion (PROM) during their course of rehabilitation. This is important as the compliance of the soft tissue structures must be established for the eventual proper positioning of the heel of the foot during the swing phase/back side mechanics of the running gait cycle. However, during actual running performance this heel position is only achieved by AROM efforts of the knee, and not due to passive motion (Figure 1).


Figure 1: The Heel/foot Position during the Sprinting and Running Gait Cycle

Why is this foot position important in the running gait cycle?

It has already been stated how the sprinting/running gait cycle is a “cycle” and thus if one part of the cycle is inefficient (the swing phase) the total cycle will also become inefficient (the stance phase). One common cue to ensure the proficiency for the transition of athlete’s backside mechanics to front side mechanics is instructing them to “step over the knee”, as the swing leg moves forward to transition to the initial ground contact of the stance phase of the running cycle. The proper positioning of the heel to the buttock assist to ensure that proper backside mechanics will occur to place optimal force into the ground surface area during the brief period of the stance phase of sprinting/running cycle.

Not establishing a proper heel position due to the lack of knee AROM creates a greater lever arm (distance from) the hip musculature as well as establishes a situation that makes it extremely difficult for the athlete to “step over” the knee (Figure 2).

Figure 2 A heel and foot position due to a lack of knee AROM

Figure 2: Heel and foot position due to a lack of knee AROM

As a result of this unsuitable foot placement, during the swing phase transition, the foot will likely pass below the opposite knee resulting in greater friction or “braking” at the time of ground contact. In conversations with various track and field sprint coaches, it has been stated that the combination of inefficient back side mechanics resulting in an unproductive total running cycle, as well as the addition of the consequential increased friction (braking) that also occurs, likely results in a one hundredth of a second increase in running time for each leg cycle performed. How does this affect the athlete’s running performance? Let’s assume that a fairly good 40 yard dash will require the athlete to complete the task in approximately 18 strides. If an inefficient running cycle due to a lack of knee AROM exists, and a likely increase of .01 seconds per stride then transpires, then the following scenario is likely to ensue:

18 strides X .01 seconds = up to an additional .18 seconds (slower) for the 40 yard sprint 

Poor backside sprinting mechanics likely results in slower sprint times.

How is AROM of the knee achieved during the rehabilitation process?

AROM of the knee should be initiated in the early stages of rehabilitation and progressed throughout the rehabilitation process until proper AROM heel/foot placement is achieve for optimal sprinting/running performance.

The initial stages of rehabilitation – During the initial stages of rehabilitation AROM exercises may be implemented at the same time the patient initiates their PROM exercises. In a standing position the patient will initially attempt to flex their knee to a 90 degree position or greater with the post-op knee pointed straight down toward the ground surface area (Figure 3a).


Figure 3a: Post-op Standing Knee Flexion, Figure 3b: Modified Wall Drill

Modified wall drills may also be incorporated when the patient/athlete is full weight bearing without the use of an assisted device. Wall drills are performed with the athlete facing a wall and placing both arms fully extended against the wall. The athlete assumes a slight forward lean in their posture and performs the exercise via the single post-op leg “stepping” or “marching” via hip and knee flexion and extension, as well as ankle dorsi flexion while maintaining this upper body posture throughout the exercise performance. Lower extremity exercise performance should occur with very little ground impact (Figure 3b).

The intermediate stages of rehabilitation – As the athlete progresses with their rehabilitation modified Mach drills may be incorporated, when appropriate, into the athletes program to continue to achieve the proper heel/foot and thigh height position necessary for optimal swing phase running performance. Mach drills are track and field drills established by track and field coach Gerard Mach that include the “A”, “B” and “C” series. Modified “A” marches may be instituted to also initiate linear movement during the exercise performance (Figure 4). Ground contact impact forces should also be kept to a minimum during the athletes exercise performance.


Figure 4: “A” Marches

The proper hip/thigh/knee height position during running performance is not also necessary for optimal running proficiency but also for the ideal application of force into the ground surface area. Often times the hip flexors are strengthened with the application of weight intensity during exercise performance. Although weighted exercise performance will increase this muscle group’s level of strength, often times the emphasis of the exercise performance is on the amount of weight the athlete can lift and not the appropriate height of the hip/thigh/knee during the exercise performance. Optimal hip/thigh/knee height also results in a favorable hip extensor range of motion (ROM) for ideal application of ground force production. This is analogous to the baseball pitcher who achieves a greater shoulder external rotation (ER) resulting in a greater ball velocity.

As the athlete progresses in their rehabilitation and exercise advancement is safely permitted, low impact butt kicks may now be performed at low exercise volumes. Butt kicks are performed with the upper body assuming the same position as wall drill performance. The difference with this exercise performance is as the athlete stands in place, both knees pointing toward the ground surface area. The athlete then “butt kicks” by alternatingly flexing each knee quickly while attempt to make contact with the heel of each foot at the corresponding gluteal fold (Figure 5).

Figure 5: Alternating Leg Butt Kicks

Figure 5: Alternating Leg Butt Kicks

Mach “A” drills may also be progressed to “A” skips as the athlete now “skips” instead of marching emphasizing exercise technique with appropriate thigh height and heel position with corresponding low ground impact. The exercise is initially performed for short distances.

The advanced stage of rehabilitation – As the rehabilitation prescription progresses and the standing butt kick exercise is advanced to “continuous” butt kicks. The exercise is performed with the heel of each foot alternating rapidly to make contact with the buttocks for initial short durations of time.

“A” skips may be replaced with “A” runs. “A” runs are the last exercise instituted prior to the athlete’s initiation to actual running. “A” runs are performed with the athlete performing the “A” skip technique at higher velocities with a modified cyclical pattern, while attempting to have the heels of each foot make contact with each buttock. The rehabilitation professional should be aware that ground contact impact will increase due to the enhanced velocity of this exercise performance, thus the exercise should initially be performed for short distances and distances should be increased safely and appropriately.

Proper foot positioning is essential for backside and overall running mechanics. This foot placement is often overlooked during the rehabilitation process as emphasis is often placed of the achievement of full passive knee range of motion and not the active motion necessary for optimal running mechanics. Running is a cyclical event in nature and the ability to perform optimally during the swing phase will affect the efficiency and force output that occurs during the initial ground contact and stance phase of the sprinting/running cycle.

Finding Your Ideal Squat Depth


I’ve discussed squat depth in multiple articles over the past couple of years. I’ve talked about hip anatomy HERE, and I’ve talked about buttwink HERE. But how do you know what your ideal squat depth is?


Get down into the squat position and find the exact moment where you start to lose your lumbopelvic positioning – you need to keep the arch in your lumbar spine – no going into flexion, and keep the tilt in your pelvis – no going into posterior pelvic tilt. Make sure you stay planted on your heels and don’t rise up onto your toes. From there, you can determine if you want to go slightly deeper, but keep in mind that there’s only so much wiggle room and it may be best to play it safe. Here’s a video that better explains it: