Assessment of the risk and biomechanical consequences of lateral epicondylalgia by estimating wrist and finger muscle capacities in tennis players

Abstract

Previous studies suggested that a pronounced weakness of the extensor muscles relative to the flexor muscles could increase the risk of occurrence of lateral epicondylalgia. This study investigates this hypothesis by estimating the ratio of extensor to flexor muscle capacities among healthy non-players (n = 10), healthy tennis players (n = 20), symptomatic players (n = 6), and players who have recovered from lateral epicondylalgia (n = 6). Maximum net joint moments in flexion or extension were measured during seven tasks involving the voluntary contraction of wrist and fingers. Using these data, the muscle capacities of the main muscle groups of the hand (wrist flexors, wrist extensors, finger flexors, finger extensors, and intrinsic muscles) were estimated using a musculoskeletal model. These capacities were then used to compute the extensor/flexor capacity ratios about the wrist and the finger joints. Compared to healthy nonplayers, healthy players presented higher extensor muscle capacities and greater capacity ratios showing that playing tennis generates specific adaptations of muscle capacities. Interestingly, symptomatic players, similar to those of non-players, showed more imbalanced ratios than healthy players. These results confirm that the ratio of extensor/flexor muscle capacities seems to be associated with lateral epicondylalgia and can be further used to understand its incidence and consequences.

Modelling force-length-activation relationships of wrist and finger extensor muscles

“…This study provided a model of the force-length behaviour of the ECR and EDC muscles capacities represent a risk factor for lateral epicondylalgia [37], these relationships could help to design tool handles and recommendations for manual tasks such that extensor muscles remain close to their optimal length when they are highly involved. By describing how muscle capacities are affected by joint posture, the models obtained in the present study could also be used to clarify how biomechanical constraints might influence the muscle coordination during grasping tasks.…”

“…sewing or hammering, and the muscle coordination varies according to the task constraints [3]. Considering the balance of muscle capacities between flexors and extensors 9 can influence the muscle coordination and might represent a risk factor in lateral epicondylalgia [37], providing a framework to analyse the force-generating capacities of those muscle groups appears necessary.…”

Electromyography‐informed musculoskeletal modeling provides new insight into hand tendon forces during tennis forehand

“…Finally, the musculo-skeletal model relied on generic muscle capacities, for example, PCSA, whereas studies showed that tennis playing modifies the hand musculature nonuniformly across hand flexors and extensors. 24 The obtained muscle load sharing could have thus been modified if the musculo-skeletal model included player-specific capacities. Nevertheless, obtaining this player-specific muscle strength profile would have required another measurement session, whereas the protocol already lasted 2 h and a half on average.…”

“…12,23 Those studies showed that both flexion-extension (FE) and radialulnar deviation (RUD) are facing high torques with values around 5-15 Nm and reaching sometimes 30 Nm, thus similar to maximal isometric contraction performances. 24 Authors also showed that the distribution of the wrist torque between the two degrees of freedom can vary importantly according to the player's individual technique, with for instance larger RUD torques in professional players and larger FE torques in intermediate ones. 23 Although the net moment traduces the overall mechanical demand at the joint, it does not allow to characterize how forces are shared across individual muscles.…”

“…Such approaches were used to study the upper limb during tennis playing and a few studies provided values at the wrist during serve 20–22 and during the forehand 12,23 . Those studies showed that both flexion‐extension (FE) and radial‐ulnar deviation (RUD) are facing high torques with values around 5–15 Nm and reaching sometimes 30 Nm, thus similar to maximal isometric contraction performances 24 . Authors also showed that the distribution of the wrist torque between the two degrees of freedom can vary importantly according to the player's individual technique, with for instance larger RUD torques in professional players and larger FE torques in intermediate ones 23 .…”