Power and Maximum Strength Relationships During Performance of Dynamic and Static Weighted Jumps

Abstract

The purpose of this study was to investigate the relationship of the 1 repetition maximum (1RM) squat to power output during countermovement and static weighted vertical squat jumps. The training experience of subjects (N = 22, 87.0 +/- 15.3 kg, 14.1 +/- 7.1% fat, 22.2 +/- 3.8 years) ranged from 7 weeks to 15+ years. Based on the 1RM squat, subjects were further divided into the 5 strongest and 5 weakest subjects (p <or= 0.05). Squat jumps were performed with a countermovement or statically at 2 different sessions spaced 1 week apart. Jumps were performed with weights ranging from 10 to 100% of the 1RM squat. A maximum effort was made for each trial; subjects performed jumps (feet left the floor) with weights up to approximately 90% of 1RM. Squat-jump power was determined using the V-scope 120. Results indicate strong correlations (r = 0.77-0.94) between the 1RM squat and both countermovement and static jump power up to 90% of 1RM. The highest power outputs for both jump conditions occurred at 10% of the 1RM and decreased as the relative intensity increased. Comparisons of weak and strong subjects indicate that as maximum strength increases the percentage of 1RM at which peak power occurs also increases (40 vs. 10% of 1RM). From a practical aspect, to improve jumping power output, these results suggest that improving maximum strength should be a primary component of training programs and that strength training should shift from lighter (10% 1RM) to heavier (40% 1RM) loads.

Effect of Load Positioning on the Kinematics and Kinetics of Weighted Vertical Jumps

“…Weighted jumps are likely to be effective exercises for developing power based on a number of factors. In the scientific literature peak power values as large as 4750 to 6250 W (≈ 45 to 70 W/kg) have been reported for male athletes performing the SBJ (5,9,36). In addition, research comparing exercises used frequently by athletes to develop lower-body power (squat, power clean and SBJ) demonstrated that the SBJ produced the largest power values.…”

“…The jump squat has been used extensively by researchers to investigate the load-power relationship (4,5,9,13,35,36,38). The rationale for the extensive study is the thesis that the load which maximises power provides the most effective stimulus for power development (4) Initial results from studies investigating the load-power relationship with the jump squat reported that power was maximized with loads of 30 to 60% 1RM (4,35,36,38). However, more recent studies have consistently shown that power is maximized when vertical jumps are performed unloaded (5,8,9,13).…”

Load That Maximizes Power Output in Countermovement Jump

“…The problem is the procedure for assessment, ie Cormie et al 18 measured the peak power and in our study we measured average power, so it becomes more difficult to make comparisons between studies. By contrast, Stone et al 12 recorded that the optimum load to achieve maximum power in squat jump and CMJ EL was 10% RM, but keep in mind that in this work the lowest charge made was this. Another study by Harris et al 26 found that the maximum power for both the peak power (PP) and for average power (P avg ) was attained with loads of 21.6 ± 7.1% and 39.0 ± 8.6% of the RM in the squat, respectively.…”

“…According to Stone et al 12 maximum strength is related to power production and that increases in maximum strength may lead to an increased in power production. One possible explanation may be due to the increase of maximum strength at a given absolute load that may represent a relative load (% RM) lower, so that as the work of Gonzalez-Badillo et al 1 this lower percentage can be shifted at a higher speed, with a subsequent increase in power for this load.…”

“…The question of which is the relative load (%1RM) that produce the P max has been one of the most controversial topic for researches. The percentages of 1RM with which the maximum power is achieved are not clear, and, according to different authors, it has been found considerable variability from 10 to 80% of 1RM in the relative loads that produce the P max , depending on the type of exercise performed and/or muscle groups involved, experience of subjects involved (novice vs. well-trained athletes) and the type of training performed [11][12][13][14] and methodological measures of power type 15 .…”