Muscle performance during maximal isometric and dynamic contractions is influenced by the stiffness of the tendinous structures

• Published in: Journal of applied physiology (1985) 2005-09, Vol.99 (3), p.986-994
• Main Authors: Bojsen-Moller, Jens, Magnusson, S. Peter, Rasmussen, Lars Raundahl, Kjaer, Michael, Aagaard, Per
• Format: Article
• Language: English
• Subjects: Adult; Biological and medical sciences; Elasticity; Fundamental and applied biological sciences. Psychology; Human performance; Humans; Influence; Isometric Contraction - physiology; Knee Joint - physiology; Male; Movement - physiology; Muscle Contraction - physiology; Muscle, Skeletal - diagnostic imaging; Muscle, Skeletal - physiology; Muscular system; Physical Endurance - physiology; Psychomotor Performance - physiology; Stress, Mechanical; Striated muscle. Tendons; Tendons; Tendons - diagnostic imaging; Tendons - physiology; Torque; Ultrasonography; Vertebrates: osteoarticular system, musculoskeletal system
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.01305.2004

Institute of Sports Medicine Copenhagen/Team Danmark Test Center, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark Submitted 19 November 2004 ; accepted in final form 19 April 2005 Contractile force is transmitted to the skeleton through tendons and aponeuroses, and, although it is appreciated that the mechanocharacteristics of these tissues play an important role for movement performance with respect to energy storage, the association between tendon mechanical properties and the contractile muscle output during high-force movement tasks remains elusive. The purpose of the study was to investigate the relation between the mechanical properties of the connective tissue and muscle performance in maximal isometric and dynamic muscle actions. Sixteen trained men participated in the study. The mechanical properties of the vastus lateralis tendon-aponeurosis complex were assessed by ultrasonography. Maximal isometric knee extensor force and rate of torque development (RTD) were determined. Dynamic performance was assessed by maximal squat jumps and countermovement jumps on a force plate. From the vertical ground reaction force, maximal jump height, jump power, and force-/velocity-related determinants of jump performance were obtained. RTD was positively related to the stiffness of the tendinous structures ( r = 0.55, P < 0.05), indicating that tendon mechanical properties may account for up to 30% of the variance in RTD. A correlation was observed between stiffness and maximal jump height in squat jumps and countermovement jumps ( r = 0.64, P < 0.05 and r = 0.55, P < 0.05). Power, force, and velocity parameters obtained during the jumps were significantly correlated to tendon stiffness. These data indicate that muscle output in high-force isometric and dynamic muscle actions is positively related to the stiffness of the tendinous structures, possibly by means of a more effective force transmission from the contractile elements to the bone. ultrasonography; squat jump countermovement jump; connective tissue; rate of torque development Address for reprint requests and other correspondence: J. Bojsen-Møller, Institute of Sports Medicine Copenhagen/Team Danmark Test Center, Bispebjerg bakke, 23, bygn 8, Bispebjerg Hospital, 2400 Copenhagen NV, Denmark (E-mail: jbm01{at}bbh.hosp.dk )