Vertical jump capacity is a common measure used to assess power ability in a number of sports. Moreover, the vertical jump itself is frequently used together with other explosive body weight exercises in strength and conditioning programs aimed at developing muscular power and athletic performance1.
The loaded jump squat is a popular variation of the vertical jump that adds external resistance, which serves to increase the force requirement of the exercise but at the same time decreases speed and rate of force development2.
Weighted jumps have become one of the most popular resistance exercises for developing muscular power based on the fact that ballistic movements avoid deceleration, which occurs during the concentric phase of all traditional resistance exercises such as the squat. This deceleration is detrimental to power development3-6.
The most popular form of the weighted vertical jump is the weighted squat jump, in which a barbell is placed over the shoulders as shown in the figure below. The traditional barbell squat is also shown for comparison.
Fig. 1. Hexagonal Barbell Jump Squat
Fig. 2. Barbell Jump Squat
To perform the exercise, athletes lower their body to a chosen depth and then quickly reverse the movement, while attempting to jump as high as possible. While initial studies suggested that peak power in the jump squat could be achieved with a range of loads from 30-60% of 1 repetition maximum (1RM)3, 7-9, more recent studies have reached a consensus that an ‘unloaded’ jump squat consistently produces maximal power10-13.
However, a recent study has shown that performing the jump squat with a hexagonal barbell as opposed to a straight barbell results in significantly greater peak power production when used with a load of 20% 1RM14. The improved power production seen with the odd-looking hexagonal barbell is thought to be due largely to how the load is positioned relative to a normal barbell. When compared to a jump squat performed with the traditional barbell technique, the hexagonal barbell allows the athlete to more closely replicate their unloaded jumping technique, therefore not adversely affecting the outcome of the jump15. As such, with hexagonal barbell jump squats the external load is positioned in a more biomechanically advantageously manner.
Loaded with this information, researchers from Dublin, Ireland wanted to test whether relative peak power output during performance of the hexagonal barbell jump squat correlated with acceleration speed during 10m and 20m sprints and height in the counter movement jump in a group of professional rugby union players. While the superiority of the hexagonal barbell for peak power production had been proven in the lab – it was yet to be seen if the results could be produced in professional athletes with a minimum of two years structured resistance training under the supervision of a qualified strength and conditioning coach.
To test their theory, the researchers had seventeen professional rugby union players perform 10m and 20m sprints, followed by a set of 3 unloaded counter movement jumps and a set of hexagonal barbell jump squats at a previously determined optimal load corresponding with peak power output.
To determine optimal load in the hexagonal barbell jump squat, participants were tested at external loads equivalent to 10%, 20%, 30% and 40% of their box squat 1RM. This is because optimal load in the hexagonal barbell jump squat has been shown to be highly individualised due to the varying bodyweight of athletes. Peak power output for each load was calculated using specialised force plates.
The researchers observed strong significant positive correlations between relative peak power output in the hexagonal barbell jump squat and counter movement jump height. While a strong, significant inverse correlation was observed between hexagonal barbell jump squat relative peak power output and 10m and 20m sprint times.
The findings of the study suggest the hexagonal barbell squat holds a lot of promise as a training tool for improving power output in athletic performance. So next time you’re at the gym watching someone using a hexagonal barbell somewhat bemused, just remember their potential for optimising power development in competitive sport.
- Cormie P, et al. Developing maximal neuromuscular power. Part 2. Sports Med. 2011;41:125-146.
- Moir G, et al. The influence of familiarization on the reliability of force variables measured during unloaded and loaded vertical jumps. J Strength Cond Res. 2005;19:140-145.)
- Baker D, et al. The load that maximizes the average mechanical power output during jump squats in power-trained athletes. J Strength Cond Res. 2001;15:92-97.
- Baker D. Improving vertical jump performance through general, special and specific strength training. A brief review. J Strength Cond Res. 1996;10:131-136.
- McBride JM, et al. The effect of heavy- vs light-load jump squats on the development of strength, power and speed. J Strength Cond Res. 2002;16:75-82.
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- Thomas GA, et al. Maximal power at different percentages of one repetition maximum: Influence of resistance and gender. J Strength Cond Res. 2007;21:336-342.
- Bevan RH, et al. Optimal loading for the development of peak power output in professional rugby players. J Strength Cond Res. 2010;24:43-47.
- Cormie P, et al. Power versus strength-power jump squat training: Influence on the load-power relationship. Med Sci Sports Exerc. 2007;39:996-1003.
- Cormie P, et al. Optimal loading for maximal power output during lower-body resistance exercises. Med Sci Sports Exerc. 2007;39:340-349.
- Dayne AM, et al. Power output in the jump squat in adolescent male athletes. J Strength Cond Res. 2011;25:585-589.
- Swinton PA, et al. Effect of load positioning on the kinematics and kinetics of weighted vertical jumps. J Strength Cond Res. 2012;26(4):906-913.
- Turner ST, et al. Peak power in the hexagonal barbell jump squat and its relationship to jump performance and acceleration in elite rugby union players. Journal of Strength and Conditioning Research. Published ahead of print.