การเปรียบเทียบระดับแรงเบรกแบบเอ็คเซ็นตริกที่แตกต่างกัน ขณะแบกน้ำหนักกระโดดที่มีผลฉับพลันต่อพลังกล้ามเนื้อในนักกีฬาชายที่มีความแข็งแรงสัมพัทธ์สูง / ธงทอง ทรงสุภาพ = A Comparison of different eccentric braking loads during weighted jump squat on the acute effect of muscular power in high relative strength male athletes
The purpose of this research was to compare the effect of different eccentric braking loads during weighted jump squat on the acute effect of muscular power in high relative strength male athletes. Eighteen male athletes (11 rugby football players and 7 sprinters) of ages between 18 to 22 years old from Chulalongkorn University were purposively sampled to be subjects in this study. All subjects participated in a counterbalanced design comprising four types of weighted jump squat performed in 2 sets of 6 repetitions at 30% of 1RM with varying levels of eccentric braking load, namely 0%, 30%, 60% and 90%. On the experimental day, peak power, relative peak power, peak force, relative peak force and peak velocity were measured during sessions by ballistic measurement system. The obtained data were analyzed in terms of means and standard deviations, one-way analysis of variance with repeated measure and multiple comparisons by the LSD were also employed. The statistical significance of this study was accepted at p < .05 level. The results were as follow: 1. There were no significant differences in peak power and relative peak power during propulsive phase between different levels of eccentric braking load but there were significant differences during landing phase between 90% level comparing with 0%, 30% and 60% levels of eccentric braking load at the .05 significance level. 2. There were significant differences in peak velocity during propulsive phase between 0% level comparing with 30%, 60% and 90% levels of eccentric braking load at the .05 significance level. In conclusion, the results demonstrated that eccentric braking loads at 30% and 60% levels are more optimal for weighted jump squat training to improve muscular power than eccentric braking loads at 0% and 90% levels.