Comparative Responses to Squats Done With Free Weights and an Exoskeleton

To assess the comparative similarity of squat data collected as they wore a robotic exoskeleton, female athletes (n =14) did two exercise bouts spaced 14 days apart. Data from their exoskeleton workout was compared to a session they did with free weights. Each squat workout entailed a four-set four-repetition paradigm with 60-second rest periods. Sets for each workout involved progressively heavier (22.5, 34, 45.5, 57 kg) loads. The same physiological, perceptual and exercise performance dependent variables were measured and collected at both workouts. Per dependent variable, Pearson correlation coefficients, t-tests and Cohen’s d effect size statistic compared the degree of data similarity between values obtained from the exoskeleton and free weight workouts. Results show peak O2, heart rate and peak force data produced the least variability. In contrast far higher inter-workout variability was noted for peak velocity, peak power and EMG values. Overall, an insufficient amount of comparative similarity exists for data collected from both workouts. Due to the limited similarity, data obtained from the exoskeleton does not exhibit an acceptable degree of validity. Likely the cause for the limited similarity was due to the brief amount of familiarization subjects had to the exoskeleton prior to actual data collection. A familiarization session that accustomed subjects to squats done with the exoskeleton prior to actual data collection may have considerably improved the validity of data obtained from that device.