Date of Award


Document Type


Degree Name

Master of Science (MS)


PURPOSE: The aim of this study was to investigate the acute effects of circuit training exercises on stable and unstable surface with and without blood flow restriction (BFR) on several physiological measures (heart rate, blood pressure, muscle unit activation and rate of perceived exertion).

METHODS: Sixteen recreationally active, males (age= 24.3 ± 1.2); n=8) and females (age= 23.1 ± 0.9); n=8) completed four testing sessions, no blood flow restriction (NBFR) on a stable surface, NBFR on an unstable surface, BFR on a stable surface, and BFR on an unstable surface. Participants performed lower body exercises in a circuit like routine, which consisted of 6 exercises for 2 rounds. Electromyography (EMG) electrodes were placed at one-third the distance over the longitudinal axis of the vastus lateralis (VL) and half the distance between the greater trochanter and lateral femoral epicondyle over the rectus femoris (RF). For the BFR sessions, BFR cuffs were placed on the upper most portion of the thigh, with an initial restrictive pressure (IRP) of 50 mmHg and a total restrictive pressure (TRP) depended on their leg circumference.

RESULTS: Generally, a significant (p < 0.05) leg main effect for both EMG RMS and MDF values for RF muscle were found and significant (p<0.05) surface and time (p<0.05) main effects were found for both EMG RMS and MDF values for VL muscle. Repeated measures ANOVA revealed significant differences for surface (p < 0.05) and time (p < 0.05) for heart rate and systolic blood pressure. Repeated measures ANOVA revealed significant increases in rate of perceived exertion values for the BFR session (p < 0.01)

CONCLUSION: No significant changes in several physiological responses were observed in the present study. However, since the values for several independent variables were generally higher compared to the other conditions, vi proper adjustments to the study procedure during circuit and BFR training may provide benefits for cardiorespiratory system, skeletal muscle strength and size. Instability training adds a greater emphasis on trunk muscle activation; therefore, this form of training may also provide a new alternative way of resistance training with a greater emphasis on trunk activation and balance.

Granting Institution

University of Texas Brownsville



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