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Muscle Damage and Adaptation in Natural Male Competitive Bodybuilders

Muscle damage is induced after performing unaccustomed exercise, consisting of eccentric muscle contractions, whereby common symptoms include a prolonged loss of muscle force generating ability or muscle function loss and delayed onset muscle soreness (DOMS). The magnitude of eccentric exercise-induced muscle damage has been well documented concluding that when the same or similar exercise is repeated the symptoms of muscle damaged is reduced, this phenomena is referred to as the repeated bout effect and similarly the protective effect. Many studies have looked at muscle damage and the symptoms of muscle damage with “untrained” individuals, and a number of studies have investigated muscle damage in resistance-trained individuals; however no previous studies have investigated muscle damage and the repeated bout effect of competitive bodybuilding athletes. Since these athletes perform a large volume of training regularly, and frequently include submaximal eccentric contractions in their training routines, the magnitude of muscle damage is likely to be minor; however, there is anecdotal evidence that bodybuilders often experience DOMS after training. Thus, it is interesting to systematically investigate muscle damage of competitive bodybuilders after performing unaccustomed advanced overloading bodybuilding training.

Therefore, the purpose of this study is to examine the extent of muscle damage that occurs to natural competitive bodybuilders after an unaccustomed training bout and to compare between the first and second bout of the training for changes in muscle damage markers to investigate whether the repeated bout effect exists.

Outcome measures will include maximal voluntary isometric contraction, barbell bench throw, maximal concentric contraction of the elbow extensor torque via an isokinetic dynamometer, plasma creatine kinase activity, muscle soreness upon palpation, flexibility and MVIC using a visual analogue scale and muscle flexibility of the pectoralis and triceps brachii muscles. These will be measured before, immediately after and 24, 48 and 72 hours after each training, to observe changes in each criterion measure over time for the first bout, and to compare the changes in each criterion measure over time between the first and second bout.

Project duration



Mr Kennedy Blowfield
Professor Ken Nosaka
Associate Professor Greg Haff

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