Free-Weight Resistance Exercise Versus Weight Machines on Pulse Wave Reflection

Abstract

Acute resistance exercise (ARE) has a large effect on pulse wave reflection, but the data are limited when examining these responses after free-weight (FW) versus weight-machine (WM) exercises. PURPOSE: To evaluate alterations in pulse wave reflection after FW exercise compared to WM exercise in resistance-trained individuals. METHODS: Individuals volunteered to participate in either FW (n=25) or WM (n=16) resistance exercises. Data were collected at rest, and 10-15min after ARE. The FW group completed 3 sets of 10 repetitions at 75% 1-repetition maximum (1RM) on the squat, bench press and deadlift, while the WM group completed 3 sets of 10 repetitions at 75%1RM on the leg press, lat pulldown, leg extension, chest press, and the leg curl. A 2x2x2 analysis of covariance (ANCOVA) was used to analyze the effects of group (FW, WM) across condition (ARE, control) and time (rest, recovery) with workload as a covariate. RESULTS: The groups were similar for anthropometrics (p>0.05), but differed in years spent training (FW: 7±4 yrs; WM: 4±2 yrs, p=0.0001). There were no differences at rest for any measures of pulse wave reflection. Neither group nor condition had an effect on brachial or aortic blood pressure. There was a significant 3-way interaction for heart rate (FW: rest: 59±8bpm, recovery: 88±13bpm; WM: rest: 65±9bpm, recovery: 89±13bpm, p=0.04) such that it was augmented during recovery from resistance exercise in the FW group compared to the WM group. There were also significant 3-way interactions for the augmentation index (FW: rest: 116±8.4%, recovery:121.2±9.5%; WM: rest: 116.8±8.4%, recovery: 113.7±5.5%, p=0.006), augmentation pressure (FW: rest: 5.0±2.9mmHg, recovery: 8.4±5.9mmHg; WM: rest: 4.3±4.0mmHg, recovery: 3.8±3.6mmHg, p=0.029), and the augmentation index normalized at 75bpm (FW: rest: 4.9±8.1%, recovery: 24.1±14.5%; WM: rest: 8.7±12.3%, recovery: 16.8±8.2%, p=0.015) such that they were increased in the FW group compared to the WM group during recovery from ARE, which differed from the control. CONCLUSION: These data demonstrate that recovery from free-weight resistance exercises has significant effects on pulse wave reflection that supersede those of weight machine resistance exercises in resistance-trained individuals, despite no differences in brachial or aortic blood pressures.