title: The influence of the biarticularity of the gastrocnemius muscle on vertical-jumping achievement.
abstract: Hypotheses concerning the influence of changes in the design of the human musculoskeletal system on performance cannot be tested experimentally. Computer modelling and simulation provide a research methodology that does allow manipulation of the system's design. In the present study this methodology was used to test a recently formulated hypothesis concerning the role of the biarticularity of the gastrocnemius muscle (GAS) in vertical jumping [Bobbert and van Ingen Schenau, J. Biomechanics 21, 249-262 (1988)]. This was done by comparing maximal jump heights for a model equipped with biarticular GAS with a model equipped with a monoarticular GAS. It was found that jump height decreased by 10 mm when GAS was changed into a monoarticular muscle. Thus, the hypothesis formulated by Bobbert was substantiated, although quantitatively the effect is small. Our result differs from that of Pandy and Zajac [J. Biomechanics 24, 1-10 (1991)], who performed similar model calculations. It is shown that the results described by these authors can be explained from the moment-arm-joint-angle relation of GAS at the knee in their model.
authors.affiliation: Faculty of Human Movement Sciences, Vrije Universiteit, Amsterdam, The Netherlands.
authors.forename: A J
authors.initials: AJ
authors.lastname: van Soest
authors.forename: A L
authors.initials: AL
authors.lastname: Schwab
authors.forename: M F
authors.initials: MF
authors.lastname: Bobbert
authors.forename: G J
authors.initials: GJ
authors.lastname: van Ingen Schenau
mesh_terms: D000843:Ankle Joint / Q000502:physiology; D001696:Biomechanical Phenomena; D003198:Computer Simulation; D015444:Exercise / Q000502:physiology*; D006621:Hip Joint / Q000502:physiology; D006801:Humans; D007719:Knee Joint / Q000502:physiology; D007866:Leg / Q000502:physiology*; D008954:Models, Biological; D009132:Muscles / Q000502:physiology*