title: Effects of plyometric training on passive stiffness of gastrocnemii muscles and Achilles tendon.
abstract: Plyometric training is commonly used to improve athletic performance; however, it is unclear how each component of the muscle-tendon complex (MTC) is affected by this intervention. The effects of 14 weeks of plyometric training on the passive stiffness of the gastrocnemii muscles and Achilles tendon was determined simultaneously to assess possible local adaptations of elastic properties. The passive force-length relationship of the gastrocnemii MTC and elongation of the gastrocnemii muscles were determined using ultrasonography during passive cyclic stretching in 19 subjects divided into trained (n = 9) and control (n = 10) groups. An upward trend in stiffness of the gastrocnemii MTC (P = 0.09) and a significant increase in the intrinsic gastrocnemii muscle stiffness were found (P < 0.05). In contrast, no significant change in gastrocnemii tendon stiffness, or in muscle and tendon geometry, was determined (P > 0.05). Considering the lack of change in gastrocnemii muscle geometry, the change in the gastrocnemii muscle stiffness may be mainly due to a change in the intrinsic mechanical properties of the muscular tissues.
authors: Laboratoire Motricité, Interactions, Performance-EA 4334, UFR STAPS, Université de Nantes, 25 bis Bd Guy Mollet, 44 322, Nantes cedex 3, France. Christophe.cornu@univ-nantes.fr
authors: Alexandre
authors: A
authors: Fouré
authors: Antoine
authors: A
authors: Nordez
authors: Christophe
authors: C
authors: Cornu
mesh_terms: D000125:Achilles Tendon / Q000000981:diagnostic imaging / Q000502:physiology*; D000222:Adaptation, Physiological; D000293:Adolescent; D000704:Analysis of Variance; D000843:Ankle Joint / Q000502:physiology*; D001696:Biomechanical Phenomena; D004548:Elasticity; D004576:Electromyography; D005602:France; D006801:Humans; D008297:Male; D008954:Models, Biological; D009119:Muscle Contraction; D053580:Muscle Strength; D053581:Muscle Strength Dynamometer; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging / Q000502:physiology*; D059385:Plyometric Exercise; D016059:Range of Motion, Articular; D013997:Time Factors; D019415:Torque; D014463:Ultrasonography; D055815:Young Adult