Tag Archives: kinematics

The Long Femur and Squat Mechanics

The squat is one of the best exercises to improve performance, period. Athletes incorporate the squat into their workout regimen because it increases strength and power of the entire lower extremity and significantly activates the core muscles. Unfortunately, performing the squat improperly can lead to significant injury.
Without getting into too much detail, there are 4 main reasons why a person may not be able to squat with good technique.
 
  1. Poor ankle mobility, primarily dorsiflexion
  2. Poor hip mobility, primarily hip flexion and external rotation
  3. Muscle weakness/muscle imbalance of the lumbo-pelvic-hip complex
  4. Long femur (a high femur to torso length ratio or high femur to short tibia ratio)
 Three of the above can be fixed with corrective exercise. This might shock you but there is no corrective exercise program that will lengthen the torso and shorten your femur (yes, that is sarcasm). Unless you are skilled at removing portions of the femur with a chainsaw you’re not going to fix #4.
Squatting with a long femur can lead to low back injury. In the image here you can see that the individual with the long femur has an increased forward lean. The excessive lean increases load at the low back.
I love the video here. If you move to the 3:40 mark the video shows an individual squatting with long femurs squatting.

It drives me bonkers when a provider (athletic trainer, personal trainer, therapist, etc.,) attempts to correct a client’s squat mechanics by forcing changes in items 1, 2, or 3 when the real problem is the unfixable number 4. Before you waste a client’s running them through a corrective exercise program make sure it is something that can be fixed.
If you have a long femur to short torso ratio you do have options!
  1. Widen the stance
  2. Externally rotate the legs
  3. Raise the heels
 If you continue watching the video (around the 5:30 mark) you will notice how the individual’s squat mechanics are improved by making subtle changes in body positioning.

All of these options change the lever arms and evenly distribute the weight between the low back, knees, and feet. Thus, one joint is not excessively loaded more than the others. You can try adjusting one of the above items or mix and match any three of the above.
 

The Squat: Should Your Knees Travel Past the Toes?

Should the knees migrate past the toes when performing a squat? I posted this question on downloadsocial media, and the immediate response by most was “No!”. I expected this answer from most everyone, from novice to advanced lifters. To you, I happily say, you’re wrong! The debate on proper squat mechanics will never die, but I am going to steal a line from Randy B., an athletic training, and performance enhancement peer, who answered my question: “Absolutely, [the knees] should [go past the toes]. Don’t believe urban legends or follow sports med sacred cows!” I couldn’t have said this any better! Randy is spot on. This urban legend could lead to injury. The purpose of this blog is to shed some light on the debate and provide the rationale for proper squat technique.

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Knee Pain? Ignore it; Fix the Hip!

I have posted on this topic many, many times. Unfortunately, many still revert to antiquated rehabiltiation protocols. Thus, I feel compelled to keep talking about it.  If you or a client has knee pain focus on the hip, not the knee. There is so much data out there on linking decreased glute strength to knee pain. A weak or inhibited glute medius is unable to control femoral internal rotation and obligatory knee frontal plane motion.  These motions are a primary cause in knee pain – traumatic and acute. Today I discovered two, recently-published, systematic reviews to prove my point.

The first review examined 47 studies which looked at factors causing Patellofemoral Pain Syndromeknee_patella_intro01  (PFPS) (1). This review identified decreased muscle strength for hip abduction and hip external rotation as an important factor associated with the cause of PFPS. The pooled data also found increased Q-angle and sulcus angle to be factors – both of which have been linked to muscle imbalance.

The second systematic review was more specific by evaluating gluteal muscle activity – via EMG – and PFPS (2). The authors identified ten studies to be included in their review, with six of these studies considered to be high-quality and eight studies having a score of 8 or higher on the Downs and Black scale. The authors conclude there is moderate to strong evidence linking delayed or short Glute medius muscle activity to PFPS. The authors also state, “If gluteal muscle activation is delayed, frontal and transverse plane hip motion control may be impaired, leading to increased stress on the PFJ and subsequent symptoms associated with PFPS.”

Rehabilitation practitioners should note this when developing rehabilitation programs. Specifically targeting glute weakness and inhibition will limit hip internal rotation and obligatory knee frontal plane motion. Correcting faulty movement patterns will allow for optimal neuromuscular recruitment and joint kinematics, ultimately relieving or preventing pain.

If you are wondering which exercises will target the glute medius look at the study published in the recent JOSPT (3) and my recent blog titled “The Glute vs TFL Muscle Battle: Proper Exercise Selection to Correct Muscle Imbalance. The data represented in the JOSPT article demonstrate the bilateral bridge, unilateral bridge, side step, clam, squat and two quadruped exercises are best for activating the glute medius.

Are you ready to change your rehabilitation program?

References:

  1. Lankhorst NE, Bierma-Zeinstra, SMA, and van Middelkoop, M. Factors associated with patellofemoral pain syndrome: a systematic review.  Br J Sports Med.  2013;47:193–206.
  2. Barton CJ, Lack, S, Malliaras, P, and Morrissey, D. Gluteal muscle activity and patellofemoral pain syndrome: a systematic review. Br J Sports Med. 2013; 47:207–214.
  3. Selkowitz, DM, Beneck, GJ, and Powers CM. Which Exercises Target the Gluteal Muscles While Minimizing Activation of the Tensor Fascia Lata? Electromyographic Assessment Using Fine-Wire Electrodes. J Orthop Sports Phys Ther. 2013; 43(2):54-64.