title: Muscle force per cross-sectional area is inversely related with pennation angle in strength trained athletes.
abstract: 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.
authors.affiliation: Faculty of Human Health Science, Tokyo Metropolitan University, Tokyo, Japan. ikegawa@opal.famille.ne.jp
authors.forename: Shigeki
authors.initials: S
authors.lastname: Ikegawa
authors.forename: Kazuo
authors.initials: K
authors.lastname: Funato
authors.forename: Naoya
authors.initials: N
authors.lastname: Tsunoda
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kanehisa
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Fukunaga
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Kawakami
mesh_terms: D000328:Adult; D000886:Anthropometry; D054874:Athletic Performance; D001696:Biomechanical Phenomena; D006801:Humans; D007537:Isometric Contraction; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D018485:Muscle Fibers, Skeletal / Q000502:physiology; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000502:physiology*; D010806:Physical Education and Training / Q000379:methods; D011336:Probability; D012680:Sensitivity and Specificity; D034941:Upper Extremity; D014891:Weight Lifting