Electronic Theses and Dissertations

Date of Award

1-1-2018

Document Type

Dissertation

Degree Name

Ph.D. in Health and Kinesiology

Department

Health, Exercise Science, and Recreation Management

First Advisor

Jeremy P Loenneke

Second Advisor

Melinda W. Valliant

Third Advisor

Paul D. Loprinzi

Abstract

This study examined the acute and chronic effects of resistance exercise with and without blood flow restriction (BFR) on skeletal muscle. Methods: The acute study examined changes in torque, muscle thickness (MTH), and surface electromyography (EMG) in response to resistance exercise with high load [70% 1RM,(7000)], low load [15% 1RM,(1500)], low load with moderate (BRF) [15% 1RM+40%BFR(1540)], or low load with greater BFR [15% 1RM+80%BFR(1580)]. The chronic study investigated changes in MTH, strength, and endurance following 8-weeks. Acute results: Following exercise, the 7000 condition had lower (p<0.05) MTH [4.2(1.0) cm] compared to the 1500 [4.4 (1.1)cm], 1540 [4.4(1.1)cm], and 1580 [4.5(1.0cm] conditions. This continued 15 minutes post. Immediately following exercise torque was (p<0.05) lower in the 1500 [31.8 (20) Nm], 1540 [28.3(16.9) Nm] and 1580 [29.5 (17) Nm] conditions compared to the 7000 condition [40 (19) Nm]. 15 minutes post, 1500 and 1540 conditions demonstrated lower torque compared to the 7000 condition. For the first three repetitions of EMG the 7000 condition displayed greater amplitude compared to all low load conditions (p<0.001). For the last three repetitions percentage EMG was greater in the 7000 compared to the 1580 condition. Chronic results: 1RM strength changes were greater in the 7000 condition [2.09 (95% CI=1.35-2.83) kg] compared to all low load conditions. For isometric and isokinetic strength there were no changes. For endurance there was a main effect for time [mean pre to post change = 7.9 (4.3–11.6) repetitions]. At the 50% site, the mean change in MTH in the 7000 condition [0.16 (0.10-0.22) cm] was greater than all low load conditions. For the 60% site, the mean change in MTH [0.15 (0.08-0.22)] was greater than all low load conditions. For the 70% site there was a main effect for time [mean pre to post change = 0.09 (0.5–0.14 cm]. Conclusions: Very load loads produce a similar acute response regardless of pressure. This response was greater than that observed in the 7000 group. Very low loads produce skeletal muscle growth. However, this response is not as robust as that observed following high load training.

Available for download on Thursday, July 23, 2020

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