In men new to weightlifting, a specific workout routine using dumbbells for rows and biceps curls, done twice a week for eight weeks with maximum effort per set, leads to high participation rates and...
Mechanism
Synthesis from 1 study
When beginners do arm curls with one dumbbell until they can't lift it anymore, their biceps get worked harder than when they do exercises that use other muscles too, because no other muscles are helping out. This extra strain makes their arm muscles grow thicker and stronger over eight weeks of...
Most probable mechanism
When untrained men do single-arm bicep curls to exhaustion, the biceps and nearby muscles are worked harder than when doing exercises that involve other muscles too, because no other muscles are helping out. This extra strain triggers signals inside the muscle cells that tell the body to build more muscle protein, making the muscles thicker and stronger over time, as shown in the study with DOI 10.1519/JSC.0000000000003234.
Single-joint biceps curls apply mechanical load exclusively to the elbow flexors (biceps brachii and brachialis), preventing compensation from other muscle groups and enabling full range-of-motion failure under load, maximizing tension on target fibers (10.1519/JSC.0000000000003234).
High mechanical tension and metabolic stress from training to concentric failure activate intracellular signaling pathways, including mTOR and MAPK, which increase protein synthesis and reduce protein breakdown (10.1519/JSC.0000000000003234).
Sustained activation of these pathways over 8 weeks of twice-weekly training leads to net accretion of myofibrillar proteins, increasing muscle fiber cross-sectional area and measurable muscle thickness (10.1519/JSC.0000000000003234).
Progressive overload and repeated exposure to high-intensity contractions enhance neuromuscular efficiency, increasing motor unit recruitment and force production, resulting in measurable strength gains (10.1519/JSC.0000000000003234).
Evidence from Studies
Supporting (1)
Community contributions welcome
Single-Joint Exercise Results in Higher Hypertrophy of Elbow Flexors Than Multijoint Exercise
Contradicting (0)
Community contributions welcome
Gold Standard Evidence Needed
According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.