METABOLIC AND KINETIC ENERGY EXPENDITURE IN RUNNING ON A NON-GRADED TREADMILL AT VARIOUS SPEEDS

The Problem. The problem of the study was to investigate the relationship between kinetic and metabolic energy expenditure during various running speeds performed on a non-graded treadmill. In addition, the investigation undertook to determine if the metabolic energy expenditure differences existed among subjects, and to observe whether or not these differences were reflected in and attributable to kinetic energy.;Findings. Metabolic and kinetic energy per unit distance increased with increasing speeds. Maximum oxygen uptake and percent of work done aerobically are positively related and both in turn are negatively related to metabolic efficiency. For every one percent increase in speed, metabolic energy expenditure increased approximately 1.6 percent. Inertial kinetic energy was the principle contributor to the total body kinetic energy, and its percent contribution to the total increased with increasing speed while the vertical kinetic energy percent contribution correspondingly decreased. Linear, quadratic, and exponential relationships were high for both metabolic-kinetic energy and metabolic-speed relationships. Metabolic efficiency-mechanical efficiency of running had a high inverse relationship.;Conclusions. Speed, maximum oxygen uptake, and percent of energy expended aerobically influence metabolic energy expenditure efficiency. Metabolic energy efficiency, not kinetic energy efficiency, influences differences in mechanical efficiency among subjects within speeds. Increases in total body kinetic energy between speeds are influenced primarily by the body's inertial kinetic energy. Linear, quadratic, and exponential relationships can predict with a high degree of accuracy the speed-metabolic energy and kinetic energy-metabolic energy relationships for the speeds tested.;Implementations. The data suggest that energy efficient running is best achieved by a low metabolic response and is not dictated by a low external work response as measured by kinetic energy. Low metabolic responses were related to good aerobic responses. Therefore, in long distance running, where energy efficiency is important, the development of the aerobic system is essential.;Procedures. The data were obtained from nine male Indiana University graduate students ranging in ages from 23 to 36. Tests on each subject were conducted on a level grade for six minutes at speeds of 229.3, 242.7, 256.1, and 269.6 meters/minute. Metabolic energy was determined by obtaining the oxygen uptake by the open circuit method of calorimetry. This was done during the run and for 30 minutes after the run. Caloric expenditure was then derived by determining the R.Q. of the gases collected. Measurement of kinetic energy was derived from two dimensional processed film, digitized for segmental endpoint coordinates, and translated into kinetic energy data by the filmdat computer program.;Recommendations. Future research concerning metabolic and kinetic energy relationship in running should include (1)the calculation of kinetic energy by taking segmental lengths and mass directly from the subjects rather than from Dempster's averages; (2)a greater range of speeds including competitive level speeds, examined as to kinetic energy efficiency, metabolic energy efficiency, and mechanical efficiency; (3)experimental designs in which speed is based upon a subject's percent of aerobic capacity and anaerobic threshold; (4)three dimensional cinematographical analyses, to include lateral kinetic energy in the calculation of the total body kinetic energy expenditure.