title: Acute effects of static stretching on leg-spring behavior during hopping.
abstract: Despite the fact that a stiffer leg spring is prerequisite for achieving a better performance during sports activities, effects of various types of warm-up on the leg stiffness is not well-known. The purpose of this study was to determine if static stretching influences the leg stiffness during two-legged hopping. Fourteen male subjects performed two-legged hopping at 2.2 Hz before and after a 3-min passive stretching of the triceps surae (dorsiflexion of 30°). Based on a spring-mass model, we calculated leg stiffness, which is defined as the ratio of maximal ground reaction force to maximum center of mass displacement at the middle of the stance phase. It was found that there was no significant difference in leg stiffness after passive static stretching. These results suggest that 3-min passive static stretching does not affect the leg-spring behavior and stiffness regulation during two-legged hopping. Finally, possible explanations for the invariant leg stiffness after the passive stretching are discussed.
authors.affiliation: Motor Control Section, Department of Rehabilitation for the Movement Functions, Research Institute, National Rehabilitation Center for Persons with Disabilities, 4-1, Namiki, Tokorozawa, Saitama, Japan. h.hobara@gmail.com
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Hobara
authors.forename: Koh
authors.initials: K
authors.lastname: Inoue
authors.forename: Emika
authors.initials: E
authors.lastname: Kato
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Kanosue
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena / Q000502:physiology; D005080:Exercise Test; D006801:Humans; D007866:Leg / Q000502:physiology*; D008297:Male; D008954:Models, Biological; D009068:Movement / Q000502:physiology*; D052580:Muscle Stretching Exercises / Q000379:methods; D011187:Posture / Q000502:physiology; D016059:Range of Motion, Articular / Q000502:physiology; D013177:Sports / Q000502:physiology; D013997:Time Factors; D019415:Torque