Early Changes of Hamstrings Morphology and Contractile Properties during 10 d of Complete Inactivity

Purpose The hamstrings (HS) muscle group plays a fundamental role in maintaining knee stability, thus contributing to the prevention and rehabilitation of lower limb musculoskeletal injuries. However, little is known about HS structural and functional adaptations after periods of prolonged inactivity. Our purpose was to investigate the HS morphological and contractile properties changes during 10 d of bed rest (BR). Methods Ten young healthy males underwent a 10-d BR. HS cross-sectional area (CSA) (at 30%, 50%, and 70% of femur length) and biceps femoris long head (BFlh) architecture were assessed by ultrasound imaging after 0 d (BR0), 2 d (BR2), 4 d (BR4), 6 d (BR6), and 10 d (BR10) of BR, whereas BFlh contractile properties (radial twitch displacement [Dm] and contraction time [Tc]) were evaluated at the same time points by tensiomyography. HS muscle volume was assessed by magnetic resonance imaging at BR0 and BR10. Results A reduction in muscle volume was observed in BFlh (P = 0.002; Δ = −3.53%), biceps femoris short head (P = 0.002; Δ = −3.54%), semitendinosus (P = 0.002; Δ = −2.63%), semimembranosus (P = 0.002; Δ = −2.01%), and HS pooled together (P
Source: Medicine and Science in Sports and Exercise - Category: Sports Medicine Tags: APPLIED SCIENCES Source Type: research