Untrained young men who perform resistance training twice a week for eight weeks at moderate intensity show measurable increases in maximal strength for the bench press, bent-over row, and back...
Mechanism
Synthesis from 1 study
When untrained men lift weights twice a week at moderate intensity, their nerves get better at turning on more muscle fibers, and their muscles get slightly thicker from the stress of lifting — together, these changes let them lift heavier weights, as shown in the study with DOI...
Most probable mechanism
When untrained men lift weights twice a week at moderate intensity, their muscles generate tension that triggers both nerve and muscle changes: their nervous system learns to recruit more muscle fibers more efficiently, and their muscle fibers grow slightly thicker over time — together, these changes let them lift heavier weights, as shown in the study with DOI 10.3389/fphys.2023.1301535.
Resistance exercise generates mechanical tension across muscle fibers during concentric and eccentric contractions, activating intracellular signaling pathways including mTORC1, which increases protein synthesis and muscle fiber growth, as observed in both set structures in the study with DOI 10.3389/fphys.2023.1301535.
Repeated lifting recruits low-threshold motor units initially, followed by high-threshold motor units as fatigue accumulates, increasing the total number of muscle fibers activated during maximal efforts, as described in the study with DOI 10.3389/fphys.2023.1301535.
Neural adaptations, including increased motor unit firing rate and reduced inhibition from Golgi tendon organs, enhance voluntary force production without requiring muscle growth, as inferred from strength gains exceeding changes in muscle thickness in the study with DOI 10.3389/fphys.2023.1301535.
Increased myofibrillar protein synthesis leads to greater muscle fiber cross-sectional area, contributing to higher force capacity, as directly measured by increased muscle thickness in the pectoralis major, biceps brachii, and rectus femoris in the study with DOI 10.3389/fphys.2023.1301535.
The combined increase in neural drive and muscle size elevates maximal force output during voluntary contractions, resulting in higher 1RM strength for the bench press, bent-over row, and back squat, as directly measured in the study with DOI 10.3389/fphys.2023.1301535.
Evidence from Studies
Supporting (1)
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Effect of resistance training programs differing in set structure on muscular hypertrophy and performance in untrained young men
Contradicting (0)
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