What you think you look like while running and what you actually look like are two very different things. Unless constantly running alongside a full-length mirror, it’s impossible to notice the nuances of a running pattern. In life we love symmetry, equilibrium and balance. There is beauty in proportion, and it’s found throughout nature – a perfectly shaped leaf, a butterfly with patterned, mirrored wings. It’s one of the most prevalent themes in art, architecture, and design in cultures all over the world and throughout human history. Aesthetically, symmetry is visually pleasing. We even look for it in our partners symmetrical people more attractive (Little et al., 2011). But aesthetics is not the only part of our lives where we seek balance. The pursuit of “work/life balance” has become as elusive as the search for the holy grail. The balance between work and leisure time is the coveted state of well being and equilibrium that is constantly sought but rarely achieved.
Running is no different, because symmetry —or a lack thereof— plays a crucial role in both running performance and injury occurrence in runners. An asymmetrical body could be the cause of a niggling injury, or the barrier blocking you from a new PB. At the end of the day, all runners want to get better at their sport and prevent injury. Differences in muscle strength, joint range of motion, flexibility, balance, and mechanics between sides of the body is one of the elements often highlighted as a risk factor for injury.
But in reality physical symmetry in runners is just like “work/life balance” – it is a myth. The human body is not a volkswagon car …. It is inherently asymmetrical making it impossible and unrealistic for any runner to achieve complete symmetry. All runners have a dominant side that’s typically stronger than the other side. When one side — in the case of running, one leg can’t pull its own weight, the stronger side has to work harder to compensate. Over time, the added impact and stress can cause problems with joints, muscles, tendons and ligaments, leading to general pain and overuse injuries. In runners with a single-leg overuse injury, there is often significant differences in strength between the hip muscles on the injured and non-injured side (Niemuth et al., 2005). Even the fastest man in history Usain Bolt is lopsided. The world record-holder in both the 100 and 200-meter hit a top speed of around 27 mph (43.5 kph), and has clearly established himself as the greatest sprinter of all time. But Bolt had an uneven, asymmetrical stride. This was established by linking his running mechanics to ground reaction forces. Bolts right leg strikes the ground with 13 percent more peak force than his left leg, and his left leg stays in contact with the track about 14 percent longer than the right (Clark et al., 2017). The most feasible reason for Bolt’s running asymmetry is the effects of his scoliosis (his right leg is functionally 1/2 inch shorter than his left). This makes it clear that that 100% symmetry is extremely rare. It’s easy to find asymmetry in all of us—small discrepancies in leg length, scoliosis or ankle flexibility to name a few so it isn’t a question of whether or not asymmetry exists, but rather how much of it. Simple observations, like a marked difference in glute strength, hamstring flexibility or even an inability to rotate as far to one side well may indicate an asymmetry that needs to be addressed because disregarding the more obvious differences may be a recipe for injury and poor performance. So Just like in “work/life balance” achieving equilibrium may prove impossible for most of us but it shouldn’t stop us trying.
Clark KP, Ryan LJ & Weyand PG. (2017). A general relationship links gait mechanics and running ground reaction forces. J Exp Biol 220, 247-258.
Little AC, Jones BC & DeBruine LM. (2011). Facial attractiveness: evolutionary based research. Philos Trans R Soc Lond B Biol Sci 366, 1638-1659.
Niemuth PE, Johnson RJ, Myers MJ & Thieman TJ. (2005). Hip muscle weakness and overuse injuries in recreational runners. Clin J Sport Med 15, 14-21.