- The purpose of this study was to determine the effect of adding load to either the feet or thighs on biomechanical and physiological measures of running performance. Fifteen subjects performed treadmill running at 12.0 km/hr for each of the following load conditions: (1) no added load, (2) 0.25 kg added to each thigh, (3) 0.25 kg added to each foot, (4) 0.50 kg added to each thigh, and (5) 0.50 kg added to each foot. Oxygen consumption and heart rate data were collected and high speed films were taken at 100 fps for each load condition. The films were analyzed to yield measures for selected temporal and kinematic descriptors of the running cycle including stride length, single leg support time, swing time, and flight time. Also measured from film were the mechanical work done on the foot, shank, thigh, and total leg during the swing phase and the contributions of the joint reaction forces and moments of the lower extremity to these work measures.
The results demonstrated that oxygen consumption and heart rate increased nearly linearly as load was increased on both the thighs and feet. The increases in oxygen consumption due to foot loading--approximately 0.7% for each 100 g of load--were nearly twice as great as those due to thigh loading. Heart rate was found to be a less sensitive measure of the increased demand due to loading rather than oxygen consumption.
While there was very little change in the temporal and kinematic descriptors of the running cycle, the results showed that the mechanical work done on the lower extremity increased as load was increased. These changes, however, were limited to the segment which was loaded. The increases in work were proportional to load magnitude, but were considerably greater for foot loading than for thigh loading. The results also showed that the increases in work were due almost totally to the increases in the inertia of the loaded segment. With respect to the relative contributions of the joint reaction forces and joint moments, the results indicated that the joint reaction forces played a greater role in doing work during the swing phase than the joint moments.
- Dissertation Note:
- Ph.D. The Pennsylvania State University 1983.
- Source: Dissertation Abstracts International, Volume: 45-01, Section: A, page: 1180.
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