Muscle Force per Cross-sectional Area is Inversely Related with Pennation Angle in Strength Trained Athletes

• Published in: Journal of strength and conditioning research Vol. 22; no. 1; pp. 128 - 131
• Main Authors: Ikegawa, Shigeki, Funato, Kazuo, Tsunoda, Naoya, Kanehisa, Hiroaki, Fukunaga, Tetsuo, Kawakami, Yasuo
• Format: Journal Article
• Language: English
• Published: United States National Strength and Conditioning Association 01-01-2008; Lippincott Williams & Wilkins Ovid Technologies
• Subjects: Adult; Anthropometry; Athletic Performance; Biomechanical Phenomena; Bodybuilding; Fibers; Humans; Isometric Contraction; Life sciences; Male; Muscle Contraction - physiology; Muscle Fibers, Skeletal - physiology; Muscle Strength; Muscle, Skeletal - physiology; Muscular system; Physical Education and Training - methods; Probability; Sensitivity and Specificity; Ultrasonic transducers; Upper Extremity; Weight Lifting; Weightlifting
• ISSN: 1064-8011; 1533-4287
• DOI: 10.1519/JSC.0b013e31815f2fd3

The present study aimed to examine the effect of pennation angle on the force per cross-sectional area for elbow extensor muscles in strength-trained athletes. A total of 52 male bodybuilders (n = 32) and Olympic weightlifters (n = 20) did maximal isometric elbow extension on an isokinetic dynamometer. Muscle cross-sectional area (CSA) and muscle-fiber pennation angle (PA) of the triceps brachii muscles were measured by ultrasonography. Bodybuilders had significantly greater isometric elbow extension force (F), CSA and PA than weightlifters. The ratio of force to CSA (F/CSA) of bodybuilders was significantly lower than that of weightlifters. A significant positive correlation was observed between CSA and PA in both groups (r = 0.832, P < 0.001, and r = 0.682, P < 0.001, for bodybuilders and weightlifters, respectively). The F/CSA was negatively correlated to PA both for bodybuilders (r = -0.408, P < 0.05) and weightlifters (r = -0.465, P < 0.05). Thus present study indicates that the larger pennation angle is associated with the lower force relative to muscle CSA in strength-trained athletes.