Proportional cross‐sectional area of the thigh muscles and isokinetic strength in women

Abstract

Twenty‐seven women (aged 19 to 24 years) were divided into groups of high and low proportional cross‐sectional area (CSA) of quadriceps (quad) and nonquadriceps (nonquad) muscle groups on the basis of computed tomography (CT) scans of the midthigh. Each subject was tested for maximum isokinetic concentric and eccentric torque in both knee flexion (0 to 1.05 rad of flexion) and knee extension (1.22 to 0.17 rad of flexion) at a velocity of 0.52 rad·s⁻¹ on an isokinetic dynamometer. A comparison of strength performance between the two groups using the Student's t test indicated that the proportional CSA of both the quad and nonquad muscles is not related to either concentric or eccentric strength under isokinetic conditions. Specific tension (nm·cm⁻²) was found to be inversely proportional to CSA for nonquad muscles under both concentric and eccentric conditions. It is hypothesized that the control of limb movement invokes a number of physiologic and neurologic mechanisms that complicate the relationship between muscle size and strength by altering the specific tension (force per unit area) of skeletal muscle. Therefore, it is concluded that in the assessment of athletes other factors besides apparent muscularity are of importance in terms of strength potential.

Keywords:

• skeletal muscle
• cross‐sectional area
• isokinetic strength
• eccentric torque
• concentric torque
• specific tension