COMPARISON OF TWO METHODS TO CALCULATE PASSIVE MUSCLE STIFFNESS IN HUMAN

The aim of the present study is to compare and to correlate the results of two methods of calculating the muscle-tendon unit stiffness. Eighteen male and 18 female healthy students performed a hamstring passive stretch at 5º/s until maximum range of motion (ROM) was reached. Angle and passive torque were measured throughout the stretch maneuver and passive stiffness was calculated using two different parts of the torque angle curve. Passive stiffness was then named stiffness10% and stiffnessIII, based on the part of the curve used for calculation of stiffness. Results showed no significant difference between both methods of calculating passive stiffness and a significant high correlation coefficient between stiffness10% and stiffnessIII. StiffnessIII method seems more reliable because of lower dispersion

COMPARISON OF VISCOELASTIC STRESS RELAXATION RESPONSE BETWEEN FLEXIBLE AND INFLEXIBLE INDIVIDUALS

The aim of this study was to compare the relaxation reaction after viscoelastic stress induced by passive static stretching during 30s between subjects with different flexibility performance. Eighteen male physical education students were randomly assigned to two groups according to flexibility level of knee extension. During the test the individuals should achieve 90% of maximal ROM and maintain the position for 30s while the stress relaxation was measured as relative decrease of torque. The results of this study show significant differences of range of motion (ROM) between the two groups, but no significant difference in stress relaxation. It can be concluded that viscoelastic stress relaxation is similar between subjects with significantly different flexibility performance after 30s passive static stretching

ANALYSIS OF THE ROM, PASSIVE TORQUE, STIFFNESS AND WORK ABSORPTION AFTER CONCENTRIC AND ECCENTRIC MUSCLE ACTIONS

Muscular strength and flexibility are two important physical capacities that are frequently assessed and trained in athletes before and during sporting competitions (Nobrega et al. 2005), but their interactions are not well established. The purpose of this study was to determine the acute effects of concentric and eccentric contractions on the range of motion (ROM), passive peak torque (PPT), stiffness and work absorption