The squat exercise is used primarily for hip and knee strengthening. It is considered one of the most fundamental strengthening exercises for strength and power in the legs. Elastic bands have been used to add resistance to the squat exercise while using barbell free weights to offer more dynamic resistance at the top of the squat movement as the resistance of the band is at its highest. No studies have directly compared the effects of squatting with elastic resistance versus free weights.
In a study published in the Journal of Strength and Conditioning Research, researchers compared squatting with equivalent work loads of elastic-resisted and isotonic free-weight squats in trained weight lifters. Subjects squatted with each type of resistance while muscle activity and biomechanical variables were measured. The band-resisted squats resulted in higher force, velocity, power, and quadriceps muscle activity near the top of the squat, which includes the first part of the eccentric phase, as well as the last part of the concentric phase.
The researchers concluded that elastic resistance produces similar resistance patterns as standard free weights, except at the bottom of the squat, where the bands are on less stretch and thus, less tension. More importantly, the researchers stated that elastic band squats “resulted in a kinetic and kinematic pattern similar to that of ballistic movement used for power training.” Although not proven in this study, using elastic resistance during the squat may maximize power output. The Thera-Band® Exercise Station may be an effective tool at improving muscular power because the elastic tubing produces highest amounts of resistance with maximal leverage at the top of the squat.
Reference: Israetel MA, et al. Kinetic and kinematic differences between squats performed with and without elastic bands. J Strength Cond Res. 2010 Jan;24(1):190-4.