The influence of resistance bands on frontal plane knee mechanics during body-weight squat and vertical jump movements.

The purpose of this study was to examine the impact of wearing a resistance band around the distal thigh on frontal plane knee mechanics during bodyweight squat and jumping exercises. Three closed-kinetic-chain exercises were examined, including: (1) bodyweight squat, (2) countermovement jump, and (3) squat jump. For each exercise, three experimental conditions were tested: (1) control condition with no band; (2) light-tension band applied around the distal thighs; and (3) medium-tension band applied around the distal thighs. Two dependent measures were used for analyses: (1) knee width normalized to ankle width and (2) peak external knee moment. In the absence of any feedback, application of the resistance bands failed to promote 'neutral' knee alignment when squatting and jumping. The stiffest resistance band resulted in significantly lower (p = 0.002) peak-width index values during the ascent phase of the countermovement jump. Additionally, the use of the medium-tension band resulted in significantly larger (p = 0.002) peak knee abduction moments compared to the no bands condition during the descent portion of the bodyweight squat and countermovement jump exercises. These findings conflict with previous clinical case reports on the proprioceptive response induced by resistance bands.