Kawakami Y, Abe T, Kuno SY, Fukunaga T

Eur J Appl Physiol 1995;72(1-2):37-43

Five men underwent unilateral resistance training of elbow extensor (triceps brachii) muscles for 16 weeks. Before and aftertraining, muscle layer thickness and fascicle angles of the long head of the triceps muscle were measured in vivo using B-modeultrasound, and fascicle lengths were estimated. Series anatomical cross-sectional areas (ACSA) of the triceps brachii musclewere measured by magnetic resonance imaging, from which muscle volume (Vm) was determined and physiologicalcross-sectional area (PCSA) was calculated. Elbow extension strength (isometric; concentric and eccentric at 30, 90 and 180degrees.s-1) was measured using an isokinetic dynamometer to determine specific tension. Muscle volumes, ACSA, PCSA,muscle layer thickness and fascicle angles increased after training and their relative changes were similar, while muscle andfascicle length did not change. Muscle strength increased at all velocities; however, specific tension decreased after training.Increase in fascicle angles, which would be the result of increased Vm and PCSA, would seem to imply the occurrence ofchanges in muscle architecture. This might have given a negative effect on the force-generating properties of the muscles.