Author: Bill

Many fitness clients and even some athletes present with very poor lumbopelvic stabilization strategies.  We’ve used a number of methods to train or retrain effective stabilization, but the wall press abs exercise shown here has made teaching much easier.  This comes from an article in the Journal of Bodywork and Movement Therapies, 2009, 13, 112-113 by Petra Valouchova, PT, and Craig Liebenson, DC.

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Bill

A new study just came out in the Journal of Sports Rehabilitation that compared EMG activity of select lower extremity muscles in the performance of a two-leg squat (TLS) and what they called a modified single-leg squat (MSLS).  For most of us, we’d call it a Bulgarian split squat or rear foot elevated split squat.

Recently, there’s been some uproar in the strength and conditioning community in regard to some coaches choosing to remove traditional TLS from their programming.  While I think there are few if any contraindicated exercises, there are contraindicated people when it comes to certain exercises such as heavy back squats for athletes with back issues or overhead pressing for people with shoulder issues. 

So when I saw this study I thought it would be of interest.  Keep in mind that this study doesn’t address the issues as to why some coaches have decided to remove heavy TLS from their programs.  I also want to note that I’m not interested in starting another debate on whether athletes or general population fitness-enthusiasts should back squat.  It is merely a comparison of the TLS and the MSLS in regard to muscle activity.  Make your own choices as to what exercises you deem appropriate based on the needs of the individual.

A few things I liked about this study:  They used real (female) athletes, they made an effort to keep the kinematics the same for tibial anterior translation and trunk inclincation for each subject, and they used legitimate loading.  One of my pet peeves is research that only uses body weight or very light loads for strength training research.  In this study they used 85% of a tested 3 rep max for both the TLS and MSLS assuring the same relative intensity.

Something I didn’t like:  The MSLS was a new exercise for the athletes.  To the researcher’s credit, they did give them practice sessions with supervised instruction to assure accurate exercise performance.  Anyone who’s trained for a while knows that you can shift the demands of a squat from a “quad dominant” strategy to a “hip dominant” strategy by shifting the hips posteriorly, increasing trunk inclination, and keeping the tibia more vertical.  Farrokhi, et. al. showed that an increased forward lean during a lunge increased the demand on the hip extensors.  By making an effort to keep the kinematics the same for each subject from TLS to the MSLS, the researchers minimized this influence of tibia and trunk angle on the muscle activity.  One average, the subjects were able to maintain just over 85% of the total system weight (body weight + barbell load) on the front leg.

The Outcome

The MSLS produced increase demands on the gluteus medius and hamstrings and reduced demands on quadriceps, whereas the TLS produce greater demands on the quadriceps with reduced hamstring and gluteus medius activity.  There was a significant difference in trunk inclination angle between the TLS and MSLS (TLS inclination was higher), but it didn’t seem to affect the muscle activity.

The researchers also noted an increased valgus angle of the knee during MSLS.  This is not an uncommon finding in research involving females and exercises demanding greater stability.

A few thougths…

I don’t think the findings are a big surprise.  The MSLS has greater demands on stability compared to the TLS, therefore muscles responsible for stabilizing the hip and knee should show increased activity.

I also don’t think this study is support for the elimination of TLS and/or double leg strength work as the “you play on one leg, so you should train on one leg because it’s more specific” crowd may feel.  The reduced quadriceps activity may be indicative of reduced overall force output.  High-speed ground-based activities like change of direction require high levels of quadriceps activity.  According to Chiu, Garhammer, and Schilling, the TLS was found to be more specific to such activities because of the high force demands.  Training solely on a single leg certainly won’t provide for the demands of high force activities.

However, improving stabilizer fatigue resistance may be an important factor in helping to maintain those high force abilities.

So which is better, MSLS or TLS?  Neither.  We benefit from both two-leg and single-leg exercises strength and power exercises in an effective sports training program.

One other small note to keep in mind.  Research only applies to the population examined, so these results may not apply to male subjects.

 References:

Journal of Sport Rehabilitation, 2010, 19, 57-70

J Orthop Sports Phys Ther., 2008, July 38(7), 403-9

Guess where I’ll be speaking this coming May?

2nd Annual Boston Hockey Summit and Basketball Symposium 

Date: Saturday, May 22nd and May 23rd at Northeastern University

Who Should Attend: Strength and Conditioning Coaches, Physicians, Certified Athletic Trainers, Coaches, Personal Trainers, and Physical Therapists who are interested in caring for and developing all those engaged in hockey and basketball.

Registration starts at 7:00 am, May 22nd.

Learning Objectives:

The specific learning or performance objectives of this lecture series are to Develop and understand evidence based recovery protocols for high level athletes.

Recognize over-training signs and symptoms and apply the appropriate recovery methods.

Recognize inappropriate movement patterns and implement corrective exercise strategies to promote healthy training and lifelong health.

Develop an appropriate unilateral lower extremity strength program and the reasoning behind the need for such a program in certain populations.

Understand the philosophy and physiology behind Whole Body Vibration and how implementing this practice may add in the recovery of knee pain.

Understand how to plan and implement an annual strength and conditioning program for the female basketball athlete taking into consideration their unique demands and injury rates.

Develop an overall assessment protocol to identify problem areas in high level athletes through both physical measures and movement.

Develop off-season conditioning and plyometric programs for high levels athletes and the reasoning for monitoring volume and intensity of those activities.

Understand the breathing demands and respiratory recovery strategies unique to the game of ice hockey and how best to train this system for optimal on ice performance.

Appreciate and understand how intensity and change of direction during practice and games, ultimately impacts total stress incurred on an athlete and how tracking only volume does not capture total stressors.

Be There!!  Art Horne has put together an outstanding group of speakers.  I’ll probably have more fun just listening and taking notes myself. 

Get more info at http://www.bsmpg.com/

Bill

P.S.  Coming up next double leg exercises v. single leg