A Pilot Study Examining Differences in Waist, Upper-arm, Mid-thigh Circumference and Body Composition When Training to Momentary Muscular Fatigue Versus Close Failure-proximity Amongst Healthy Male Biological Sex University-aged Students

Resistance training is commonly used to improve body composition, gain strength, increase muscle size (i.e., hypertrophy) and prevent muscle atrophy (i.e., muscle wasting). The most optimal mode of building muscle remains unclear, however there are many mechanisms that can be tested to yield optimal results. One variable that can be manipulated when designing a hypertrophy-focused resistance training regimen is intensity (i.e., proximity-to-failure). Proximity-to-failure is defined as the number of repetitions remaining in a set of prescribed exercises prior to reaching momentary muscular failure (MMF). MMF is when an individual cannot complete the lowering or concentric phase of a given repetition with a full range-of-motion without deviation from the prescribed form of the exercise. For all lifters, particularly amongst older populations, it can be psychologically demanding to push to MMF, and may increase the risk of delayed onset muscle soreness (DOMS) and/or injury due to technical breakdown. In contrast, there is some evidence that suggests training to a slightly less intensity (i.e., within 1-4 repetitions in reserve [RIR]) may result in comparable hypertrophic results with less of a physical and psychological demand on participants.

For these reasons, this study looks to investigate if an easier (i.e., less intense) approach to training such as training with repetitions in reserve (RIR), warrants similar or better muscle hypertrophy adaptations to MMF.