I just got back from a week with adidas at their newly remodeled headquarters at a small, farming town in Germany, where the company was first started in the 1940s. Most of our discussions were held in laboratory settings, reminiscent of a James Bond movie with brilliant technicians designing the latest in sports technology. One concept stood out, because their view on footwear is so similar to our view on training athletes. We all need to be evaluating our choices in shoes, as well as exercises, based off a mobility and stability continuum.
MOBILITY STABILITY Choose if you need
- foot strengthening - heavy lifting
- more TIME - more RATE
- all around sport training -balanced GRF performance
Our training is individualized based off a force plate, identifying an athlete’s nervous system weaknesses, particularly along this mobility and stability continuum (see Sparta Point 12/8/10). If athletes need more stability, or stiffness, they are lacking rate of force development (LOAD), which is how quickly they can create ground reaction force (GRF). Athletes needing more mobility, will excel on these LOAD measures, but need to improve their ability to maintain that GRF, or DRIVE (Sparta Point 1/27/10). To simplify these prescriptions, LOAD athletes need to pursue quicker, heavier movements like a Hang Clean, while those seeking DRIVE should target single leg lifting for more time under tension.
The beauty of footwear is that it seeks to serve this same continuum. Adidas has developed a great line of barefoot shoes, designed more for the gym rather than running. This footwear provides mobility and freedom of movement in the foot, but as such, challenges the need to stabilize upon foot impact. So athletes will actually get stronger feet, particularly through their arch muscles, by wearing and training in these shoes. However, athletes also need to sprint fast and lift heavy, especially in competition. Athletes in these endeavors will favor a stronger, more stable shoe to maximize the energy return or elasticity of these higher force/speed movements. Shoes that are too soft absorb too much force, thus limiting this energy return and minimizing stiffness. An extreme example is a weightlifting shoe that provides a higher, stiffer heel for stability during the heavy, explosive nature of Olympic lifts (see Sparta Point 8/31/10). While this discussion may seem like a marketing strategy for the original sports apparel company, no other group produces both extremes of this apparel, so I have no choice but to use these examples.
The exciting part of this footwear continuum concept is athletes can also choose their footwear off of their GRF needs, not just based off the setting of training versus competition. For example, even if an athlete that needs RATE is not in competition, a stiffer shoe would be recommended. What footwear would best fit the athlete needing time? A barefoot shoe.
We know that the most important aspect of an athlete’s performance and injury risk is GRF, how much and the balance of its variables (LOAD, EXPLODE, DRIVE). If the footwear is the only thing between the body and the ground, it seems we have been underestimating the variability options and importance of specialty footwear.
But if you’re not worried about GRF, then don’t worry about your footwear either, gravity is overrated.