A common tool used in strength and conditioning for increasing strength and power gains is variable resistance training, which involves the attachment of elastic bands or chains to ends of the barbell.
In an exercise with an ascending strength curve, where the movement is hardest at the bottom of the movement and progressively gets easier (i.e. barbell squat), the addition of bands or chains helps match the resistance curve to the strength curve, theoretically improving training outcomes.
The present study compared the effects of variable resistance training (VRT) to traditional resistance training (TRAD) on upper-body strength, power, and velocity in elite youth rugby players.
16 subjects participated in this study, who were members of an elite club rugby team. Subjects were randomly assigned to the VRT or TRAD group, completing 2 weekly upper- and lower-body strength and power sessions for 6 weeks. The two training programs were identical, except that the VRT group performed the bench press with 20% of the prescribed load coming from elastic bands.
Outcome measures included bench press 1RM, as well as bench press mean velocity and mean power at different loads, before and after the training intervention. The magnitude of the changes in each group was determined using cohen’s d effect sizes.
The researchers found that while both groups improved their bench press strength, power and velocity, the VRT group tended to experience greater improvements in mean power and velocity. Additionally, both groups experienced similar increases in bench press 1RM.
While the body of literature on variable resistance training is still inconclusive, the available research suggests that variable resistance training has some utility for increasing upper-body power, but its effects on maximal strength are comparable to traditional resistance training.