CHANGES IN MECHANICAL POWER AND RUNNING ECONOMY IN DISTANCE RUNNERS

The purpose of this study was to investigate the relationships between changes in running economy and running mechanics by using a segment kinematics approach. Six male university distance runners performed treadmill running before and after the 4 month period, while oxygen consumption and running motion were also measured. Mechanical power was calculated by a segment kinematics approach, the data for 4 of 6 subjects were analysed. Running economy for 2 of 4 subjects were improved and mechanical power were decreased. Running economy for the other 2 subjects deteriorated but change in mechanical power was different for one subject which decreased while for increasing for another subject. The relationships between changes in running economy and running mechanics varied with the individual runner

CHANGES IN THE RUNNING MOTION WITH FATIGUE DURING MIDDLE-DISTANCE RUNNING

The purpose of this study was to investigate the changes in the running motion with fatigue during middle-distance running and get the knowledge about how to maintain the running velocity under fatigued condition by comparing the running motion with fatigue to it with no fatigue. The step length at the fatigued was shorter than the non-fatigued, on the other hand the step frequency was larger than the non-fatigue. The peak ankle joint plantar flexion torque and positive torque power of the support leg at the fatigued were smaller than the non-fatigued, as well as the peak and averaged vertical GRFs. The hip joint torque and power of the recovery leg at the fatigued were significantly larger than the non-fatigued. It is appropriate for maintaining the running velocity to move the recovery leg quickly and increase the step frequency under fatigued condition

EFFECTS OF PACING STRATEGIES ON THE RUNNING MOTION OF MALE 800 METER RUNNERS

The purpose of this study was to investigate the effects of different pacing on running motion for male 800 m runners in official competitions. Ten male 800m runners were videotaped (60Hz) from the side positioned the marks of 150m (1st mark), 350m (2nd mark), 550m (3rd mark) and 750m (4th mark) of the 800m race. Kinematics and Kinetics variables were calculated. We divided ten subjects into two groups: Positive-type (POS) which consisted of five subjects with the fastest average running velocity of the 1st and 2nd marks running velocity (running velocity), Negative-type (NEG), which consisted of the five other subjects. In POS, the running velocity, the stride length per height and the shank angular velocity of the support leg were significantly decreased along the race, and the trunk inclined forward than NEG. However, the hip extensor torque, power and the knee flexor torque at the late recovery phase did not decrease. In NEG, the running velocity, the relative step frequency, the hip flexor torque at the early recovery phase, the hip extensor torque and the knee flexor torque at the late recovery phase were significantly increased at the late half of the race. The thigh and shank angular velocity of the support leg were maintained. It was concluded that the running motion of 800 m runners were affected by the pacing strategy

EFFECTS OF FATIGUE ON THE LEG KINETICS IN ALL-OUT 600M RUNNING

The purpose of this study was to study effects of fatigue on ground reaction forces (GRF) and leg kinematics in all-out 600m running (simulating a positive pacing strategy of the 800m race). Eight male middle-distance runners were asked to perform an all-out 600m run and a non-fatigued 80m run with the same velocity as at the 550m mark of the all-out 600m run. Runs were videotaped (300Hz) in 2D and the ground reaction forces were measured (500Hz) at the 150m and 550m marks of the 600m run and the 50m mark of the 80m run. Step length, GRF, ankle plantar flexion torque and knee extension torque of the support leg decreased due to fatigue. Results suggest that in the final stage of a 800m race, the runner should not try to increase step length by applying great force to the ground, but should shorten the aerial phase and step time by faster recovery phase

CHANGES IN ANGULAR MOMENTUM DURING 10,000 M RACES

INTRODUCTION: In distance running, many coaches and runners pay attention not only to leg motion but also to arm and trunk motion. Hinrich (1987) studied angular momentum in running and suggested that main role of arm and trunk motion in running was to maintain the balance about vertical axis against leg motion. Unfortunately, there was little biomechanical study about arm and trunk motion for elite distance runners in races. The purpose of this study was to investigate the angular momentum about vertical axis for elite distance runners in the 10000m races