The Importance of Eccentric Leg Strength in Female Soccer Players

Author: Matt Couch

Publish Date: Oct. 8th, 2019

Unfortunately, females suffer more ACL injuries than males. A variety of studies have been done on the physiological makeup of females versus males causing females to suffer from ACL injuries, most notable the Q angle of the hips and knees. But, in this post we are going to look at a recent study that found eccentric strength to be an important aspect for detering female ACL injuries.

Eccentric stretch is the  strength of the muscle when it is being contracted and elongated versus concentric strength where the muscle is contracting and shortening. For example, when you curl a dumbbell and bring the weight closer to your shoulder you are using concentric strength, when you lower the dumbbell away from your shoulder that is eccentric strength.

A study done by  Paul A. Jones and associates, they found that females with better eccentric strength when performing agility movements had a less likelihood of sustaining injury. The study had 3 objectives

“(1) to explore the relationships between COD (Change of Direction) performance (completion times), ECC-EXT (Eccentric Extensor) and ECC-FLEX (Eccentric Flexor) and approach velocity, (2) examine the differences between stronger and weaker players in regard to deceleration into the turn (i.e., penultimate and final contact of the turn), and (3) explore the kinetic (i.e., GRFs (Ground Reaction Forces) and hip and knee joint moments) differences between stronger and weaker players during weight acceptance (braking phase) of penultimate and final contact.”

The participants in this study were female soccer players ranging from age 17 - 25 in the weight range of 120 - 145 pounds. The females participating in the study had experience playing in the top two levels of women’s english soccer. The most significant findings included the “relative ECC-EXT strength and relative ECC-FLEX strength and COD performance time.” When observing approach velocity, pertaining to ECC-EXT, there was a large difference between stronger and weaker participants. As for ECC-FLEX, there was no significant change between stronger and weaker participants. To put this into context, the ECC-EXT would be the extension of the hip and knee joint that allows the player to explode into a sprint, in contrast the ECC-FLEX is the flexion of the hips and knees allowing the player to decelerate and slow their speed to prepare their body to change direction. Finally, the study found a significant difference in horizontal and vertical GRF associated with hip extension between stronger and weaker participants. The authors  “primary finding that eccentric strength is associated with COD performance substantiates previous findings and highlights the importance of eccentric strength in COD tasks that require substantial braking prior to initiating a direction change.” The authors go on to stress that “prior steps are pivotal in the interaction between strength, speed and technique with regard to COD performance.”

It is important to note that agility or the change of direction requires not only strength and speed but also technique. Just like passing, receiving, and shooting the soccer ball requires practicing technique, it is equally important to practice good agility technique to deter agility related injuries. If you are looking for a speed and agility program to help improve your COD I recommend checking out one of our agility ladder programs. Although this article primarily focuses on female soccer players COD, all soccer players can learn from this study and understand the importance of working on eccentric strength to deter injury and improve performance.

Reference

https://www.mdpi.com/2075-4663/5/2/42/htm