Nenad Jankovic

Optimum Drop Height for Maximizing Power Output in Drop Jump: The Effect of Maximal Muscle Strength

Abstract Matic, MS, Pazin, NR, Mrdakovic, VD, Jankovic, NN, Ilic, DB, and Stefanovic, DLJ. Optimum drop height for maximizing power output in drop jump: The effect of maximal muscle strength. J Strength Cond Res XX(X): 000–000, 2015—The main purpose of this study was to explore the cause-and-effect relation of maximal muscle strength (MS max ) on the optimum drop height (DH opt ) that maximizes power output in drop jump. In total, 30 physically active male students participated in this study, whereas the 16 subjects were selected according to their resistance strength training background (i.e., level of MS max ) and allocated into 2 equal subgroups: strong (n = 8) and weak (n = 8). The main testing session consisted of drop jumps performed from 8 different drop heights (i.e., from 0.12 to 0.82 m). The individual DH opt was determined based on the maximal value power output across applied ranges of drop heights. The tested relationships between DH opt and MS max were moderate (r = 0.39–0.50, p ⩽ 0.05). In addition, the stronger individuals, on average, showed maximal values of power output on the higher drop height compared with the weaker individuals (0.62 vs. 0.32 m). Finally, significant differences in the individual DH opt between groups were detected (p < 0.01). The present findings suggest that drop height should be adjusted based on a subjects neuromuscular capacity to produce MS max . Hence, from the perspective of strength and conditioning practitioners, MS max should be considered as an important factor that could affect the DH opt , and therefore should be used for its adjustment in terms of optimizing athletes testing, training, or rehabilitation intervention.

Comparative analysis of reaction time of elite sprinters at the world championships in 2013 and 2015

Previous studies have shown that the start and start acceleration play a significant part in achieving maximum speed in sprint. Time of the sound signal the start gun to leave the starting blocks, although limited with athletic rules, remain the domain of researchers, due to the fact that every sprinter wants to achieve shorter starting reaction time and a better result at the end of the race. The aim of this study was to analyze and compare the values of starting reaction time finalists in the 100 m, 200 m and 400 m at the World Championships in Athletics in 2013 and 2015. The results showed a statistically significant difference (p < 0,05) results in the 200 m for women, C\c = 3,14, p = 0,008 and statistically significant difference (p < 0,05) in the starting reaction time in the 100 m for men, C\c = 2,12, p = 0,05. No statistically significant differences in relation to sex.