Determining the Appropriate Height of Drop Jump for Male
Non-athletes
June, 2013 Student: Khuat Cong Toai
Advisor: Prof. Hsien – Te Peng
Abstract
Drop jump is one of the most popular plyometric exercises. There is no research suggesting about appropriate drop heights according to subject’s jumping ability. This study aimed to determine the appropriate height of drop jump by percentage of vertical jump heights for male non-athletes. Fifteen physically active college students participated in this study and performed drop jumps from heights of 50, 75, 100, 125 and 150% of vertical jump heights (DJ50–DJ150). Statistical comparisons of vertical ground reaction force (VGRF), impulse, moment, power, contact time and jump height were performed between different drop jump heights. The study found that the peak VGRF during DJ150 was significant greater than the peak VGRF during DJ50, DJ75 and DJ100. The eccentric impulses were significantly different between each drop height. All hip, knee and ankle joints power absorption during DJ125 and DJ150 were significant greater than DJ50 and DJ75. The finding suggested that drop jumps from 125% and 150% of vertical jump height are not recommended because of the lack of biomechanical efficiency and the potentially increased risk of injury.
Keywords: vertical ground reaction force, impulse, moment, power, jump height.
