Effect of Knee Isometric Flexion on Hamstring and Vertical Spine Muscle Stiffness

Abstract

Abstract MyotonPRO was used to measure the stiffness of hamstring and erector spinae muscles to investigate the degree of activation of different regions of hamstring and erector spinae muscles by isometric knee flexion at different angles, and to analyze the continuity of myofascial mechanical chains between the tissues of low back and lower extremity by the characteristics of changes in the stiffness of hamstring and erector spinae muscles to provide reference for the practical application of rehabilitation training. 20 healthy adult females were recruited, and the stiffness of semitendinosus (ST), biceps femoris muscle(BF), dominant and non-dominant side erector spinae muscles were measured by MyotonPRO at different angles (90°, 60°, 30°) of prone knee isometric flexion. We found that the stiffness of the ST and nondominant erector spinae muscles gradually increased as the knee flexion angle decreased, with the highest muscle stiffness at 30°. BF and dominant erector spinae muscles showed a tendency to increase and then decrease, with the highest muscle stiffness at 60°; there was a moderate to strong correlation between the BF and nondominant erector spinae muscles (r=0.451,p<0.05; r=0.716, p< 0.0001)The data suggest that 30°-60° is the optimal angle range for training the hamstrings and that there is a moderate to strong correlation between stiffness changes in the lower extremity muscles and the erector spinae, providing data to support the analysis of the continuity of the myofascial mechanical chain between the low back and lower extremity tissues.