title: Gender differences in human muscle and joint mechanical properties during plantar flexion in old age.
abstract: Muscle and joint mechanical properties during plantar flexion were investigated in 13 elderly women (EW) (age range 73-83 years) and 15 elderly men (EM) (age range 74-81 years). Maximal torque, at several angular velocities, was measured to construct torque-velocity relationship. This led to the calculation of an index of maximal shortening velocity (VI(max)) at 10% of maximal isometric torque. Two methods were then used to calculate musculotendinous (quick-release movements) and musculoarticular (sinusoidal perturbations) stiffness. In both cases, stiffness was linearly related to torque, and the slope was defined as a stiffness index (SI): SI(MT) and SI(MA), respectively. Maximal torques as well as VI(max) (p <.05) were lower in EW compared with EM. Furthermore, SI(MT) and SI(MA) values were higher for EW than for EM (p <.05). These results are interpreted in terms of possible differences in the muscle mass, fiber-type distribution, and tendons. They may also have implications for daily motor behavior.
authors.affiliation: Equipe Motricité-Plasticité, Faculté des Sciences du Sport, Université de Bourgogne, Dijon, France. julien.ochala@u-bourgogne.fr
authors.forename: Julien
authors.initials: J
authors.lastname: Ochala
authors.forename: Denis
authors.initials: D
authors.lastname: Valour
authors.forename: Michel
authors.initials: M
authors.lastname: Pousson
authors.forename: Daniel
authors.initials: D
authors.lastname: Lambertz
authors.forename: Jacques
authors.initials: J
authors.lastname: Van Hoecke
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D001696:Biomechanical Phenomena; D005260:Female; D005528:Foot / Q000502:physiology*; D006801:Humans; D008297:Male; D009119:Muscle Contraction; D018482:Muscle, Skeletal / Q000502:physiology*; D012727:Sex Characteristics