The Expression of the Force-Length Properties of the Gastrocnemius in Ice Hockey Players.

Leonard, C and Challis, JH. The expression of the force-length properties of the gastrocnemius in ice hockey players. J Strength Cond Res 38(9): 1635-1639, 2024-Although the force-length properties of muscles have an approximately parabolic shape, in vivo not all the force-length curve is necessarily used, only a portion of the curve is expressed (i.e., ascending, plateau, or descending regions of the force-length curve). The number of sarcomeres in series in a muscle fiber affects the expressed section of the force-length curve; this number can be influenced by the nature of activity the muscle experiences. It was hypothesized that the reduced range of motion ice skaters experience, because of the constraints imposed by the ice skates, that the gastrocnemii of a group of ice skaters will adapt and will more frequently express in vivo the plateau of the force-length curve compared with a nonspecifically trained population. Twelve NCAA Division I female ice hockey players volunteered for the study. Their maximum isometric ankle plantarflexion moments were recorded for 6 ankle angles and 3 knee angles. Exploiting the biarticularity of the gastrocnemius, the expressed sections of the subject's force-length curves were determined. Six subjects operated over the ascending limb, 5 operated over the plateau region, and 1 over the descending limb. This frequency of distribution for ice hockey players was statistically different to the distribution measured for 28 nonspecifically trained subjects from a previous study ( p < 0.0001). These results likely reflect morphological differences between the 2 groups for their gastrocnemii, potentially arising from the limited range of gastrocnemius length feasible in ice-skates. These results have implications for the specificity of their off-ice training for ice hockey players.