Take-off efficiency: transformation of mechanical work into kinetic energy during the Bosco test

Abstract

Purpose. The aim of the study is to present a new method for determining the efficiency of take-off during a 60-s bosco repeated vertical jump test. Method. The study involved 15 physical education students (age: 21.5 ± 2.4 years; height: 1.81 ± 0.08 m; mass: 76 ± 9 kg). The data were collected with the use of a pedobarographical system (Pedar-x; Novel, Munich, Germany). The statistical analysis utilized a simple linear regression model. Results. Owing to possible fatigue, flight time and flight height decreased. The average flight height was 0.260 ± 0.063 m, and the average contact time equalled 0.54 ± 0.16 s. The average anaerobic power values calculated for the 60-s work period had the mean value of 21.9 ± 6.7 W · kgbW -1 ; there was a statistically significant (p < 0.05) decrease in anaerobic power during the 60-s bosco test. Conclusions. The efficiency of mechanical work was highest at the beginning of the test, reaching values of up to 50%. The efficiency of mechanical work conversion into mechanical energy seems to be an appropriate determinant of rising fatigue during the 60-s bosco jumping test.

Jumping performance and take-off efficiency correlation with the basic anthropometric parameters in female volleyball players

“…In CON only a moderate correlation with BW was found. Like the efficiency of any machine, the efficiency of mechanical work is reduced by the internal friction in muscles and between individual muscle groups and joints (Jandova et al, 2017). The decrease in efficiency due to the fatigue can be explained because the force exerted by the subject's feet does not only contribute to the jumping take-off but also to the maintenance of a stable position before take-off.…”

“…The decrease in efficiency due to the fatigue can be explained because the force exerted by the subject's feet does not only contribute to the jumping take-off but also to the maintenance of a stable position before take-off. Therefore, η in females is usually decreasing with increasing fatigue, so subjects should pay more attention to the achievement of the proper squat position and to stabilising their posture and focusing less on their take-off (Jandova et al, 2017).…”

“…During the take-off phase muscular work, which is converted into mechanical energy during the flight phase, is performed by the athlete. When an anaerobic performance for CJ is being monitored, take-off efficiency can be monitored as well (Jandova et al, 2017).…”

Are vertical jump height and power output correlated to physical performance in different sports? An allometric approach

“…This muscle function is the stretch-shortening cycle (SSC), where the preactivated muscle is first stretched (eccentric action) and then followed by the shortening (concentric), allowing the use of elastic energy. The SSC may be observed in basic locomotion or sports movements like running, jumping and throwing [33,34].…”