- An appearance of asymmetry does not automatically imply asymmetry of function
- Asymmetrical strokes may be related to physical characteristics and physiological capacity
- Working with an asymmetrical stroke is a mix of science and art
In previous posts we have reviewed literature on swimming and asymmetries (Part I, Part II). This installment will integrate information recently published by Dr. Formosa, summarized in his interview. What seems like a simple issue can get very complex when we look at all the factors involved. Many kids have had their strokes changed simply because a coach did not like how the stroke looked. Now, I’m not suggesting that kids should be allowed to swim without correction, but rather that correction must rely on more than “it looks bad.”
Before getting to the interview, recall from a prior post in this series that, "Despite attempts to impose ideal symmetry, a perfectly symmetrical stroke and body are both unrealistic. We all have favored brain hemispheres, eye, ear and limb preferences along with structural differences in how our organs sit within our bodies. Asymmetry may also follow us into the water. But there is still good reason to make swimmers “less asymmetrical” even perfect symmetry is a fiction."
Nearly every swimmer brings asymmetries to the water. This isn’t necessarily a bad thing; just something to be accounted for when dealing with technique. A key point from the literature is that we can’t fully determine functional symmetry without measuring force. Yet surely there are ways to estimate whether someone is symmetrical or not, which leads us to Dr. Formosa’s work.
As Dr. Formosa summarized,
"The front crawl and backstroke research papers highlight that although an athlete may present with a similar timing from hand entry to hand exit the force profile that they are producing through the water is variable. Therefore, it should not be assumed that if a swimmer presents with a symmetrical timing pattern their force profile is also symmetrical.
Further, elite athletes that apply force in water based sports such as rowing and kayaking have the ability to subtly manipulate their stroke to optimise force production. The complexity of symmetry is evident with the findings that although athletes demonstrated symmetrical timing their net drag force values were asymmetrical." (Formosa 2011, 2012, 2013)
While better swimmers often deliver force symmetrically, HOW they accomplish via individual can vary greatly and requires a more critical thought process than simply how the swimmer looks. The practical implication here is that coaches must consider all the information.
We have written previously about movement screening to learn more about swimmers’ individual qualities. Not everyone has access to high tech underwater force measurement devices, but knowing your swimmer’s physical baseline is valuable. Some swimmers move their arms asymmetrically in 2D video but ultimately produce power with symmetry.
Breathing patterns are also key factors, as preferred breathing style may lead swimmers to gravitate toward an asymmetrical looking stroke. Prior injury may also lead swimmers to develop protective patterns around injury. Yet thanks to the amazing plasticity of the brain, talented athletes can learn to develop force symmetrically despite lasting mechanical limitations. The extent to which this actually happens has yet to be studied but is a possible line of inquiry for future research as the foundation of the current literature on asymmetries expands.
- Formosa, D. P., Mason, B., & Burkett, B. (2011). The force-time profile of elite front crawl swimmers. Journal of Sports Sciences, 29 (8), 811-819.
- Formosa, D. P., Sayers, M., & Burkett, B (2012). Front-crawl stroke-coordination and symmetry: A comparison between timing and net drag force protocols. Journal of Sports Sciences, 31 (7), 759 – 66.
- Formosa, D. P., Sayers, M., & Burkett, B. Symmetry of elite backstroke swimmers utilising an instantaneous force profile. Journal of Sports Sciences, Accepted 5th July 2013.
Written by Allan Phillips is a certified strength and conditioning specialist (CSCS) and owner of Pike Athletics. He is also an ASCA Level II coach and USA Triathlon coach. Allan is a co-author of the Troubleshooting System and was selected by Dr. Mullen as an assistant editor of the Swimming Science Research Review. He is currently pursuing a Doctorate in Physical Therapy at US Army-Baylor University.