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Athletic development specialists dedicated to the art and science of excellence in movement

A Lesson in Critical Thinking: Yoga and "Significant" Strength Gains

This post is about the importance of critical thinking regarding any and all claims, whether from published research or via anecdotal evidence…

If you read this blog you may have seen our previous discussion on the importance of placing yoga in the proper context (Thoughts on Yoga).  Our critique of yoga has little to do with the practice itself, and instead that manner in which it is bastardized in commercialized fitness.  Even some excellent studios have compromised their practice values to entertain the masses and attract more customers.  Further, yoga has become a convenient way for many inept running, cycling, and triathlon coaches to mask their lack of movement assessment skills (“Yoga classes at the gym are great for flexibility and recovery in endurance athletes!!!” = “I really don’t know how to physically assess your movement, so just go take some yoga classes with a room full of random people and we'll hope things work themselves out…”).

But this post is really not about yoga, and more about the importance of critically evaluating any and all claims.  Consider this recent study from the Asian Journal of Sports Medicine exploring the strength benefits of a Sun Salutation regime.  In this study, a group of male and female university students performed 24 cycles of sun salutations, 6 days a week for 24 weeks (almost six months). Authors reached the following conclusion:

"sun salutation has the potential to improve the muscle strength, general body endurance and body composition to the optimum level in healthy individuals. These components in turn, enhance an individual's physical fitness. Sun salutation does not require any tools or gadgets, limited space is enough to perform them and only a few minutes are necessary to perform a given number of cycles. Generally, resistance training which improves muscle strength and aerobic exercises which improve body endurance and body composition are believed to be the essential components of a fitness regimen. However, from the present study, it can be concluded that sun salutation is an easier and less time consuming alternative to improve strength, body composition and general body endurance.” (Bhutkar 2011)

Sounds great, right?  Yoga helps strength, improves overall fitness, doesn't take much time, and involves no equipment…yay!  Well, let’s look at the actual numbers…

Authors noted the following improvements:

  • 1 Rep Max bench press in males (29.49kg to 36.12kg) and (10.5 to 13.16)
  • 1 Rep Max shoulder press (males; 22.96 to 26.53) and females (6.83 to 8.83)
  • Max rep push-ups in male (19.0 to 21.98) and female (14.66 to 18.56)
  • Max rep sit-ups in male (24.92 to 29.84) and female (and 13.16 to 19.23)
  • A significant decrease in body fat percent was observed only in female (27.68 to 25.76) but not in male subjects.
  • BMI significantly decreased in male(21.43 to 20.87) and female (22.41 to 21.76)

For those unfamiliar with metric weights, these numbers may seem impressive merely because they are “significant” improvements.  However, conversion to imperial weights paints these numbers differently.  For instance, 29.49kg to 36.12kg is approximately a 20% increase in weight lifted for the males.  That’s nice until we convert to pounds and see their bench press went from 64.9 lbs. to 79.5 lbs.   According to the Cooper Institute, anything below 117lbs. based on the average body weight in this sample (132lbs) is “Poor” by general fitness standards.  So after nearly six months of Sun Salutation training, the group that started “Poor” remained “Poor”, nearly 50% away from “Fair” performance.  And remember, these aren’t high performance athlete standards, these are general fitness standards.  

Nearly six months in a regime for healthy college students and they remain firmly the “Poor” category is a problem, especially when the claim the “Sun salutation can be an ideal exercise to keep oneself in optimum level of fitness.”  (Bhutkar 2011) Females improved from 23 lbs to 29 lbs.  Statistically significant but again firmly in the “Poor” category in both pre-tests and post-tests.

Pushups and situp scores also scored in the “Poor” category per the testing standards used by the American College of Sports Medicine and the YMCA.  Most would agree these standards aren’t perfect (how much use does the situp test really have?), but un-sick and un-injured college aged students should not be in the “Poor” category after six months of training. 

Further, if there’s a claim about a particular exercise maintaining an “optimum” level of fitness, that claim should be substantiated, particularly with the sensationalist claims often surrounding yoga practice.  Curiously, there was no control group or a “resistance trained” group to compare gains. 

Summary

Start with a low enough baseline and nearly any training will elicit improvements.  Though improvements were statistically significant, after six months of training, healthy university aged subjects progressed from Poor to…Poor!  Had this been an eight to twelve week study (a common length involving university students), I might think differently as that's not a lot of time for massive gains.  However, with six months we'd expect more meaningful progress before labeling the intervention beneficial.  The intervention here just happened to be Sun Salutations (and to be fair, most yogis don't spend an entire six months doing only sun salutations), but the same analysis would apply with anything.  Lesson here is that sometimes you must dig into the numbers to evaluate claims with a critical eye. 

Reference

Bhutkar MV, Bhutkar PM, Taware GB, Surdi AD.  How effective is sun salutation in improving muscle strength, general body endurance and bodycomposition?  Asian J Sports Med. 2011 Dec;2(4):259-66.

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