Indirect calorimetric measurements were made on two athletes running at different speeds up to 22 km/hr at grades from -20 to +15%; the function was found to be linearly related to speed. Within these limits, the net kilocalories per kilogram per kilometer values seem to be independent of speed and related only to the incline. These values are about 5–7% lower than those found in nonathletic subjects, which shows that training in atheletes does not lead to great improvement. A nomogram is given for easily calculating the energy expenditure in running when the speed and the incline are known. The energy cost per kilometer in horizontal run (1 kcal/kg) is about double that for walking at the most economical speed (4 km/ hr). Submitted on July 31, 1962

The external and internal mechanical work in running has been measured through various procedures. Different from walking, in running the work due to the forward speed changes (variation of kinetic energy) and to the vertical displacement of the center of gravity (variation of potential energy), throughout the step cycle, are substantially in phase. The external work performed per kilometer is independent of speed, amounting to 0.25 kcal/kg km. The total mechanical work amounts to about 0.40–0.50 kcal/kg km. The efficiency in running has been calculated as about 40–50%: such a high value involves a contribution of a substantial amount of energy delivered at a very low cost; this appears to be identified as elastic recoil energy from the stretched contracted muscle and amounts to about half the energy spent in running. A mechanical model is given for the walking and running processes. mechanics of locomotion; kinetic and potential energy during step cycle; elasticity of contracted muscle; mechanical models for walking and running Submitted on July 29, 1963

No abstract

The APS Journal Legacy Content is the corpus of 100 years of historical scientific research from the American Physiological Society research journals. This package goes back to the first issue of each of the APS journals including the American Journal of Physiology, first published in 1898. The full text scanned images of the printed pages are easily searchable. Downloads quickly in PDF format.