RESUMEN
In order to re-evaluate the mechanical efficiency during bicycle pedalling the total mechanical work (internal work + external work) and the energy expenditure were determined on four adult males (20-21 years) . The subject worked on a Monark bicycle ergometer with 6 different loads (0-5kp) at a constant pedal frequency of 50rpm. The internal work (W-int) to accelerate the leg itself was determined by a cinematographic procedure used by Fenn (1930) . With the data of external work (W-ext) and energy expended above resting (E<SUB>t</SUB>-E<SUB>r</SUB>), the‘true’efficiency has been calculated as<BR>‘True’efficiency=W-int+W-ext/E<SUB>t</SUB>-E<SUB>r</SUB>×100<BR>The result obtained was as follows : 1) The time course of kinetic energy due to leg movement was similar to those in walking and running reported previously. 2) The W-int at 0kp ranged in about 70-90kgm/min. In the mean values of four subjects the W-int tend to be constant at the loads from 0 to 3kp (about 80kgm/min), but increased appreciably at higher loads of 4-5k p (about 100-110kgm/min) . 3) The ratios of W-int to W-ext were about 20-30% at lkp, 10-20% at 2kp and 5-10% at 3-5kp. 4) The efficiency of leg movement only at Okp resulted in high values of about 40-85%, suggesting energy transfer between leg and inertia wheel. 5) The efficiency values at 1 to 5kp, ranging in 23.5-36.2%, appeared to show a maximum at intermediate work loads. 6) The‘true’efficiency so calculated did not largely differ from the efficiency calculated by conventional way ; 1.5-4% higher than the work efficiency, 2-5% higher than the net efficiency, and 3-5% higher than the apparent efficiency at intermediate loads.
RESUMEN
Anthropometrical measurement were obtained on 178 male nonathletic university students and 168 male athletic university students (Swimming, Handball, Soccer, Rugby, Running, Thrower, Judo and Gymnastics) aged 18-22 years.<BR>The results obtained were as follows<BR>The mean values of height and body weight for nonathletes were 170.2cm and 59.7kg respectively. The mean values of height and body weight for athletes except gymnastics and long distance runner were larger than those for nonathletes. Athletes showed larger mean values of girth of chest than nonathletes (86.1cm) . The mean values of girth of upper arm and girth of thigh for nonathletes were 26.9cm and 50.6cm respectively. The mean values of girth of upper arm for athletes except basketball, long distance runner and jumper were considerably larger than that for nonathletes. Athletes except long distance runner, jumper and gymnastics showed larger mean values of thigh than nonathletes. The mean values of skinfold thickness for athletes except heavy weight class of judo were thinner than that for nonathletes and the percentage of body fat calculated by using the prediction formura from mean skinfold thickness, body surface area and body weight for athletes was smaller than that for nonathletes<BR>Plotting of body weight and body fat content in standard measure against height in standard measure with family of iso-deviation line was used to compare the body composition and body shape of athletes with those of nonathletes. In this plotting, physical characteristics could be expressed as the difference (R) between the points representing the mean value of athletes on the origin, (the mean values of nonathletes) and ratio of deviation (r) from standard line representing correlation of body weight or body fat content to height for nonathletes. Plotting R against r with family of lines of the same height was proposed to differentiate physical characteristics of athletes participating in different kinds of sports and to evaluate the effect of training on physical characteristics. Plotting of girth of upper arm and girth of thigh in standard measure against girth of chest was used for the evaluation of difference in body shape of athletes.