A dynamometer for evaluation of dynamic muscle work

Abstract

The validation of a new dynamometer for evaluation of dynamic muscle work is presented. The device was based on a precise measurement of load displacements of any machine using gravitational loads as external resistance. It allowed, through a sensor consisting of an infrared photo interrupter, the calculation of velocity, force and power during concentric, eccentric and stretch-shortening cycle activity. To validate the dynamometer 33 male and female track and field athletes (12 throwers and 21 jumpers) participated in the study. The throwers (4 women and 8 men) were asked to perform half-squat exercises on a slide machine with a load of 100% of the subject's body mass. The day-to-day reproducibility of half-squat exercises gave a correlation coefficient of r = 0.88, 0.97 and 0.95 for average push-off force (AF), average push-off velocity (AV), and average push-off power (AP) respectively. Comparison of half-squat measurements was performed against jumping and running test evaluation by the jumpers (7 women and 14 men). The interrelationships among the different variables studied demonstrated a strong correlation between AF, AV and AP and sprinting and jumping parameters (r = 0.53-0.97; P < 0.05-0.001). Using values of AF, AV and AP developed in half-squat exercises executed with different loads, ranging from 35% to 210% of the subject's body mass, it was also possible to establish the force-velocity and power-velocity relationships for both male and female jumpers. In any individual case, the maximal error due to the measurement system was calculated to be less than 0.3%, 0.9% and 1.2% for AF, AV, and AP respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Relationships between jump and sprint performance in first-class county cricketers

“…The findings of this study are similar to those reported by Bosco et al 8 , and Hori et al 9 who found strong and moderate inverse relationships of r = -0.93 (p<0.01) between 30 m and CMJ and r = -0.69 (p<0.01) between 20 m and CMJ performances, respectively. The correlations in this study are not as strong as those reported by Bosco et al 8 although the subjects used in the earlier study were a mixed group of male and female jump athletes which may have increased the range of values attained.…”

“…The correlations in this study are not as strong as those reported by Bosco et al 8 although the subjects used in the earlier study were a mixed group of male and female jump athletes which may have increased the range of values attained. Hori et al 9 used subjects with similar age and anthropometric characteristics to the present study, with the mean values for 20 m sprint time and CMJ height (3.17 s and 41.5 cm) similar to those reported in the present study (3.05 s and 42.8 cm).…”

“…For example, Bosco et al 8 found a very strong inverse relationship between CMJ height and 30 m sprint time (r = -0.93, p<0.01), similar to the correlation between the same variables found by Hori et al 9 (r = -0.69, p<0.01). Lopez-Sigovia et al 10 found an inverse correlation between CMJ height and 20 m sprint time of r = -0.54 (p<0.05), and Requena et al 11 found a correlation between the same variables of r = -0.47 (p<0.05).…”

Alterações em variáveis motoras e metabólicas induzidas pelo treinamento durante um macrociclo em jogadores de handebol

“…The explosive strength of the lower limbs of the handball players was indirectly measured through the vertical jump test on a resistive table connected to a digital timer, following protocol proposed by Bosco et al (11) .…”

Improving the design of squat machine using motion capture and virtual prototyping

“…In order to give an experimental measure of these forces, Bosco et al [15] proposed a validation of a new dynamometer for the evaluation of dynamic muscle work.…”