Non-uniform changes in magnetic resonance measurements of the semitendinosus muscle following intensive eccentric exercise

Abstract

This study was designed to determine the regional differences of magnetic resonance (MR) measurements in the hamstrings [biceps femoris muscle long head (BFl) and short head (BFs), semimembranosus muscle (SM), and semitendinosus muscle (ST)] following eccentric knee-flexion exercise. Twelve male volunteers performed eccentric knee-flexion exercise. Maximum isometric torque, plasma creatine kinase (CK) activity, muscle soreness, and MR images of the hamstrings were measured before and immediately following exercise, and on the first, second, third and seventh days following the exercise. Cross-sectional areas (CSAs) and transverse relaxation times (T2s) of the hamstrings were measured from the T2-weightened MR imaging sequences of 30% (proximal), 50% (middle), and 70% (distal) areas of the thigh length. The CSA of the ST at proximal and middle regions had significantly increased on the third day, but no significant changes were found for the BFl or SM. Immediately following exercise, T2 values had increased significantly in the BFs, BFl, and ST. On the third day, T2 values of only ST increased significantly at proximal, middle and distal regions. Significant differences of T2 values between proximal and distal regions in the ST were found for the second, third and seventh days following the exercise. These results suggest that because of the anatomical characteristics of the muscles, the degrees of response following the exercise differed among the muscles and the regions of ST muscle.

In vivo and in vitro Examination of the Tendinous Inscription of the Human Semitendinosus Muscle

“…This might explain the observation that fusiform muscles, such as ST, are potentially more easily injured than pennate muscles [Garrett et al, 1987]. Recent evidence seems to support this suggestion, as different responses between proximal and distal compartments to eccentric exercise were reported [Kubota et al, 2007].…”

Prevention of Hamstring Muscle Injuries in Sports

“…The results suggest that different prevention exercises affect different patterns of muscle recruitment, and this degree of response differs between proximal and distal regions. These findings, together with those by Askling et al (2006Askling et al ( , 2007Askling et al ( , 2008 and Kubota et al (2007Kubota et al ( , 2009, suggest that the prescribed intervention will depend on the injured muscle and its specific anatomic location.…”

“…Moreover, the nonuniform activation and damage of the different components of the hamstring muscle group during different strengthening exercises has recently been demonstrated (Kubota et al 2007), so targeting different parts of the hamstring with different exercises is recommended. For example, lunge exercise damages the proximal adductor and the proximal biceps femoris (Mendiguchia et al 2013) in contrast to Nordic hamstring exercises and eccentric leg curls that damaged the distal portion of the Concentric hip extension is done during descending phase, and eccentric hip extension during recovering phase in order to counteract hip flexion is done.…”

“…Core muscle activation must be emphasized during the exercise Combined hip extension and knee flexion exercise. Eccentric knee flexion is done during descending phase and concentric knee flexion concomitantly with hip extension during the ascending phase short head of biceps femoris and the proximal semitendinosus (Kubota et al 2007). …”

“…Muscle functional MRI (fmMRI) has been used to examine the intensity and/or pattern of muscle activation in commonly used preventive exercises (Kubota et al 2009). This method relies on an exercise-induced increase on transverse relaxation times leading to recruitment images that demonstrate spatial patterns and intensity of muscle activation (Sesto et al 2005;Kubota et al 2007;Larsen et al 2007). The results suggest that different prevention exercises affect different patterns of muscle recruitment, and this degree of response differs between proximal and distal regions.…”