One major goal of an athlete in any sport is to stay healthy and in action as much as possible. That goal is made difficulty to achieve without a strong foundation. Today’s topic: ankles. Two major factors at play with ankle health is range of motion and stiffness. Range of Motion (ROM): how much the joint can move in its intended direction. Stiffness: Positional integrity at any point in that range of motion. Below we lay out some details on the ankle’s role in tennis, and mechanisms of creating stiffness while in action.
Tennis players average 4 changes in direction and run 8-12 meters per point. (Gomes 2014) Considering the stress each step and each break puts on the ankle, it should be no surprise that the most prominent injury in tennis is a twisted or sprained ankle. (ITF 2019) There are precautions that can be taken such as proper footwear and a good warm up, but todays focus will be on the preventative actions that can be taken within the scope of Strength and Conditioning. (ITF 2019)
Now let’s talk change of direction (COD) mechanics. In an ideal world, hips drop, knee tracks over the foot while your chest is over the knee, hips are back while keeping good back posture, and the center of mass lays over the middle of your lead foot. In a controlled environment, that’s replicable. In a chaotic environment like tennis, not so much. The tennis player has fractions of a second to decide when and where they need to decelerate. How will they respond then? Now what about the added rotation needed during ground strokes? How does that affect the deceleration? What about when tired in the later minutes of a match? Fatigue and stress are bound to catch up. So, in this imperfect environment, the hips might not drop so low, the knees might not track so well over the feet, and the center of mass may not be over the middle of the lead foot.
When that fatigue sets in, so do the compensations. A common compensation is raising the hips. When that happens, we need to rely on other joints to distribute the force. Our ankles inevitably play a role in that distribution. If the compensation deals with knee tracking, once again, the ankles will be forced to cope with that new stressor. Considering changes in direction happen an average of 4 times per rally, small compensations add up to big stresses. (Gomes 2014)
Another variable specific to tennis is the variety of playing surfaces. Changing direction on clay is not the same as changing direction on hard or grass court. The wide variety of factors playing a role in COD make in necessary for our ankles to be able to resist movements in all planes. This goes back to range of motion and stiffness. Is our ankle mobile in each possible action of that joint? Can we generate stiffness throughout those actions? Ankle sprains and twists can be best protected through a combination of deep ROM, high capability to produce stiffness in that ROM, and ankle proprioception (awareness of the ankle joint, and knowledge of where the foot is relative to both the ground and the body).
Now let’s talk about the other side of ankles in performance. Ankles can add to our play in large part thanks to their big role in the stretch shortening cycle (SSC). The SSC is a stretch and release of the bodies soft tissues resulting in elastic energy being used in unison with the intended muscle action. (Walker 2021) When we hold tension, we are storing energy that we can then release to add a bit of “pop” to our steps. This elasticity, when timely released with a relevant muscle action, adds to the power output of a given movement. To run our fastest, a release of elastic energy needs to take place as we contract relevant muscles. Similarly, to jump our highest, not only do we use our strength, but we also use the elastic energy to act as a protagonist to the movement.
Proper use of the SSC is significantly more energy efficient than the alternative option of using only our contractile muscle to produce force. Movement efficiency is increasingly relevant as a match goes on. The more we play, the more fatigued we are. The more fatigued we are, the more we need to use our bodies free energy.
Ultimately, we want our athletes healthy and game ready. This is not likely to be done with a weak foundation. Ankle injuries are a notoriously common reason for missed matches in tennis player. While the injuries cannot be totally prevented, the likelihood of injury can be reduced with proper training. By understanding the common mechanisms of injury, a prominent example being a rolled ankle, we can strengthen positions that help avoid the detrimental motion. But while understanding injury mechanisms is important, it is also important to realize that there is no one size fits all exercise to prevent ankle injuries. A widely variable approach should be applied to help account for sports lack of predictability. Through understanding the demands and risks of tennis, we are best suited to apply exercises to both reduce risk of injury and increase movement efficiency.
Sources:
Gomes, R. V., Santos, R. C. O., Nosaka, K., Moreira, A., Miyabara, E. H., & Aoki, M. S. (2014, March 31). Muscle damage after a tennis match in young players. Biology of sport. Retrieved April 25, 2022, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3994582/
International Tennis Federation. (2019, November). Injury ankle sprain - international tennis federation. International Tennis Federation. Retrieved April 25, 2022, from https://www.itftennis.com/media/2133/injury-ankle-sprain.pdf
Walker, O. (2021, January 6).Stretch-shortening cycle. Science for Sport. Retrieved April 25, 2022, from https://www.scienceforsport.com/stretch-shortening-cycle