The effects of barbell load on countermovement vertical jump power and net impulse

Abstract

The aim of this study was to examine the effects of barbell load on countermovement vertical jump (CMJ) power and net impulse within a theoretically valid framework, cognisant of the underpinning force, temporal, and spatial components. A total of 24 resistance-trained rugby union athletes (average ± SD: age: 23.1 ± 3.4 years; height: 1.83 ± 0.05 m; body mass (BM): 91.3 ± 10.5 kg) performed maximal CMJ under 5 experimental conditions in a randomised, counterbalanced order: unloaded, and with additional loads of 25%, 50%, 75%, and 100% of BM. Peak power and average power were maximised during the unloaded condition, both decreasing significantly (P < 0.05) as load increased. Net impulse was maximised with 75% of BM, which was significantly greater (P < 0.05) than the unloaded and 100% of BM conditions. Net mean force and mean velocity were maximised during the unloaded condition and decreased significantly (P < 0.05) as load increased, whereas phase duration increased significantly (P < 0.05) as load increased. As such, the interaction between barbell load and the underpinning force, time, and displacement components should be considered by strength and conditioning coaches when prescribing barbell loads.

Effect of Barbell Load on Vertical Jump Landing Force-Time Characteristics

“…Jump height is reliant on the impulse applied to the jumper and barbell system center of mass during the propulsion phase, where impulse is the product of mean net force (force minus jumper and barbell system weight) and the time this force is applied for (17,24). Because the acceleration of gravity is constant, landing impulse should reflect propulsion impulse.…”

“…Popular load-power and load-velocity testing protocols typically require athletes to jump with progressively heavier loads (1,3,14,17,19,21,22). This could significantly increase landing forces.…”

Seasonal changes in physical qualities of elite youth soccer players according to maturity status: comparisons with aged matched controls

“…The CMJ was performed on the same portable force platform sampling vertical force (Fz) at 1000 Hz. After a 1 s quiet standing period, CMJ was performed utilising a standard technique with arms akimbo (Hori et al 2007), with no attempts made to control the depth of the countermovement (Mundy et al 2017). Each participant performed 2 jumps interspersed with 3 min rest.…”

“…Each participant performed 2 jumps interspersed with 3 min rest. Jump height was calculated using the velocity at take-off method (Mundy et al 2017) whilst net force was integrated with respect to time to obtain net impulse which was summed over the propulsion phase. ICCs and CVs for the 185 CMJ jump height were r = 0.86 and CV = 7.46% and CMJ impulse were r = 0.94 and CV = 6.67%.…”

Jump Training in Rugby Union Players: Barbell or Hexagonal Bar?

“…It is thought that these changes may have occurred due to the differences in bar placement during training. Previous research has stated that the placement of the BAR upon the posterior aspect of the shoulder during the jump squat can limit forward inclination of the trunk at the bottom of the countermovement (2,20,28) and cause larger moment arms around the knee and reduced recruitment of the hip extensor muscles (28). These changes are known to reduce jump height and power output (28).…”