Date of Award

2016

Degree Type

Thesis

Degree Name

Master of Science (Exercise & Sports Science) by Research

School

School of Medical and Health Sciences

First Advisor

Professor Ken Nosaka

Second Advisor

Associate Professor Greg Haff

Abstract

This study investigated muscle damage of bodybuilders who performed an unaccustomed intense resistive exercise bout. Ten male bodybuilders (age: 23 ± 2 y, height: 177.6 ± 6.3 cm, body mass: 85.7 ± 8.1 kg) with a minimum of 4-years resistance training experience performed 17 exercises targeting the pectoral muscles. Eight of the 10 bodybuilders repeated the same exercises two weeks later. Muscle function (bench press throw, maximal isokinetic elbow extension and flexion concentric torque: MVC torque), muscle soreness using a visual analogue scale (VAS: 100-mm), and plasma creatine kinase (CK) activity were assessed before, immediately after and 24, 48 and 72 hours after exercise. Bench press throw peak force decreased immediately (23 ± 20%) and 24 hours after the first exercise bout (9 ± 15%), but, returned to baseline (930 ± 129 N) by 48 hours post-exercise (P<0.05). MVC torque also decreased but, returned to baseline by 48 hours post-exercise. Muscle soreness peaked 24 hours post-exercise (57 ± 22 mm). No significant changes in plasma CK activity were evident after the exercise at any corresponding time point. When compared between the first and second bouts, changes in bench press throw parameters and MVC torque were similar, but muscle soreness was less (P<0.05) after the second (47 ± 26 mm) than the first bout (68 ± 27 mm). Similarly, the magnitude of volume performed was significantly greater in the second bout (11,433 ± 674 kg) as opposed to the first (10,384 ± 670 kg) due to the repetitions to volition failure (P<0.001). It is concluded that bodybuilders still experience minor loss of muscle function lasting for 2 days after unaccustomed exercise targeting the chest muscles, but muscle soreness was relatively severe, and no repeated bout effect was evident for muscle function measures, but minor repeated bout effect was evident for muscle soreness. This may be a due to potential limitations of continual adaptations.

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