Does Resistance Type Affect Force Profiles in the Squat, Bench Press, and Bench Pull?: A Comparison of Freeweights versus Pneumatic and Isokinetic Resistance
Abstract
Purpose: Resistance training induces specific adaptations depending on the resistance profile of the exercise. For example, in free-weight exercises, there is typically a distinct “sticking region” that limits the lifter's capacity and dictates a specific training stimulus. In contrast, pneumatic and isokinetic devices may provide a more evenly distributed resistance through the full range of motion and thereby result in a more versatile training stimulus for the movement. However, the training stimulus may also be related to the force amplitude, it is therefore interesting to know if this varies between freeweights, pneumatic, and isokinetic induced resistance. The study aimed to compare force profiles of free-weight exercises (bench press, squat, bench pull) with pneumatic and isokinetic resistance devices, examine force magnitudes at the bottom position, identify sticking points, average forces and determine maximum force generation.
Methods: Fifteen strength-trained adults (5 women, 10 men) performed 6-repetition maximum sets using free-weights, pneumatic, and isokinetic resistance, with sessions separated by at least 48 hours. Force measurements using force plates and a linear encoder were normalized, and Statistical Parametric Mapping (SPM) compared force curves across resistance types.
Results: Free-weights generated higher forces in the 0-15% phase for the bench press and squat compared to pneumatic and isokinetic resistance and higher forces in the bench pull compared to pneumatic resistance. 1080 Quantum Synchro showed higher average forces in squats and bench pulls and peak forces 0-100% in the squat exercise.
Conclusion: Free-weights generated higher force outputs in the 0-15% barbell displacement, particularly for the bench press, potentially increasing mechanical stress and enhancing strength and hypertrophy. Pneumatic resistance allows for higher accelerations, potentially increasing power, in addition to increased forces in the midand end-ranges. The 1080 Quantum Synchro showed higher average and peak forces 0-100%. Selecting resistance based on goals is important, with more research on longterm adaptations needed.
Description
Masteroppgave - Norges idrettshøgskole, 2024