Relationships among jump motion control ability, knee joint position sense, and adjusting muscle contraction in healthy subjects

Abstract

The purpose of this study was to investigate the correlations among motion control ability, joint position sense ability, and muscular strength adjustment ability in 15 healthy subjects. Motion control ability was measured by having participants jump with eyes closed to what they thought were distances of 25, 50, and 75% of their maximum jump in the vertical and standing broad jump. Joint position sense ability was measured by 8 tests at the left knee angle for subjects with closed eyes in seated and standing positions. Muscular strength adjustment ability was assessed by measuring the torque by Biodex System 3 of the demonstrated contraction when study subjects contracted their hip and knee extensors, and knee extensors to what they thought was 50% of their maximum voluntary muscle contraction. Results show relationships among the three abilities. We suggest that motion control ability is influenced by joint position sense ability and muscular strength adjustment ability.