INTRODUCTION Hamstring strain injuries are common in sports that involve high-speed running. It remains uncertain whether the hamstrings are susceptible to injury during late swing phase, when the hamstrings are active and lengthening, or during stance, when contact loads are present. In this study, we used forward dynamic simulations to compare hamstring musculotendon stretch, loading, and wor...

Background: Although maximal sprint speed (MSS) and the anaerobic speed reserve (ASR) provides valuable information about the speed profile of athletes, these parameters fall short of providing important information about sub-maximal metabolic thresholds. The only field test that can offer an estimate of a sub-maximal metabolic threshold is the 3-minute all-out test for running (3MT) which deli...

The purpose of this study was to compare an objective measurement of smoothness between a group of runners and a group of non-runners during running and fast walking. Smoothness was quantified by evaluating the endpoint jerk-cost (JC) at the heel. Subjects walked at a speed of 1.75 m.s(-1) and ran at a speed of 3.35 m.s(-1) on a motor driven treadmill while 2-D kinematic data (60 Hz) were colle...

The adjustment of the leg during running was addressed using a spring-mass model with a fixed landing angle of attack. The objective was to obtain periodic movement patterns. Spring-like running was monitored by a one-dimensional stride-to-stride mapping of the apex height to identify mechanically stable fixed points. We found that for certain angles of attack, the system becomes self-stabilize...

BACKGROUND AND PURPOSE Gait training with partial body weight support has been used to improve gait. In this study, changes in gait relative to speed, cadence, stride length, and percentages of stance and swing for both lower extremities (LEs) during comfortable walking, fast walking, and running were studied in a subject with an incomplete C-5 on C-6 spinal cord injury. SUBJECT AND METHODS A...

The lengths and velocities of muscle fibers have a dramatic effect on muscle force generation. It is unknown, however, whether the lengths and velocities of lower limb muscle fibers substantially affect the ability of muscles to generate force during walking and running. We examined this issue by developing simulations of muscle-tendon dynamics to calculate the lengths and velocities of muscle ...