MUSCLE ARCHITECTURE AND THE RATIO OF JOINT TORQUE TO MUSCLE VOLUME OF TRICEPS SURAE MUSCLES IN YOUNG MEN AND WOMEN

INTRODUCTION: Muscle volume is a major determinant of joint torque (Fukunaga et al., 2001). However, it is not clear whether there are gender-differences in a relationship between joint torque and muscle volume. It is not clear also about muscle architecture, e.g., physiological cross-sectional area (PCSA) and fascicle length. We aim to compare 1) muscle architecture under the maximal voluntary contraction condition and muscle volume (MVTS) of the triceps surae muscles (TS), and 2) the relationship between MVC and MVTS, for young men and women

FORCE-LENGTH RELATIONSHIPS OF HUMAN GASTROCNEMIUS AND SOLEUS MUSCLES IN VIVO

INTRODUCTION: Synergistic muscle have different architecture, and therefore could have different force-length relationships for the same joint angle changes. Previous studies have failed to reveal the force-length relationships of synergistic muscles. The purpose of this study was to investigate the force-length relationships of the triceps surae muscles for humans in vivo

Age-related site-specific muscle loss in the thigh and zigzag walking performance in older men and women

To investigate the relationships between site-specific muscle loss in the thigh, muscle quality and zigzag walking performance, 40 men and 41 women aged 65–79 years had muscle thickness (MTH) measured by ultrasound at nine sites on the anterior and posterior aspects of the body. Skeletal muscle mass (SM) was estimated from an ultrasoundderived prediction equation. Site-specific thigh sarcopenia was calculated using ultrasound-measured MTH at the anterior/posterior aspects of the thigh (AP-MTH ratio). Zigzag walking time (ZWT) and maximum isometric knee extension (KE) and flexion (KF) torques were measured. Muscle quality (torque/thigh SM) and knee joint strength index (torque/body mass) were calculated. There were no significant correlations between SM index and ZWT. However, AP-MTH ratio was inversely correlated (P < 0.05) to ZWT in men (r = −0.335) and women (r = −0.309). ZWT was also inversely correlated (P < 0.05) to KE-strength index in both sexes (men, r = −0.328; women, r = −0.372). Similarly, ZWT was correlated to KF-strength index (r = −0.497) and muscle quality (r = −0.322) in women, but not in men. After adjusting for age, height and body mass, AP-MTH ratio was inversely correlated to ZWT in men (r = −0.325) and tended to be correlated to ZWT in women (r = −0.263). Zigzag walking performance may be associated with site-specific thigh sarcopenia in older men and women