For beginners who are new to weight training, doing only compound exercises like squats and bench presses leads to the same strength gains in six key lifts as doing those exercises plus isolated...
Mechanism
Synthesis from 1 study
Big exercises like squats and bench presses make beginners stronger by teaching their nerves to use more muscle fibers at once — adding isolated moves like curls doesn’t make them stronger, even if it makes their arms a little bigger (10.4081/ejtm.2018.7827).
Most probable mechanism
When beginners do big exercises like squats and bench presses, their brain and nerves learn to activate more muscle fibers at once, which makes them stronger without needing to do isolated moves like bicep curls — this happens because compound movements naturally engage all the major muscles involved in each lift, and studies show this is enough to boost strength equally across all six lifts even without extra isolation exercises (10.4081/ejtm.2018.7827).
Multi-joint resistance exercises generate high levels of mechanical tension and neural demand across multiple muscle groups simultaneously, driving increased motor unit recruitment during each repetition (10.4081/ejtm.2018.7827).
Repeated activation of motor units during multi-joint training enhances corticospinal drive and improves the nervous system’s ability to synchronize and recruit high-threshold motor units, increasing force production capacity without requiring additional muscle growth (10.4081/ejtm.2018.7827).
The neuromuscular adaptations from multi-joint exercises alone are sufficient to produce maximal strength gains in untrained individuals across all six lifts tested, as no additional benefit was observed when single-joint exercises were added (10.4081/ejtm.2018.7827).
Less supported by current evidence, but not ruled out
Adding isolated exercises like bicep curls and triceps extensions can make the arms slightly bigger by targeting those muscles more directly, but this doesn’t make people stronger than doing only big lifts — it just adds muscle size without improving force output (10.4081/ejtm.2018.7827).
Single-joint exercises apply focused mechanical tension to isolated muscles such as the biceps brachii and triceps brachii, increasing local metabolic stress and muscle fiber recruitment beyond what is achieved during multi-joint movements (10.4081/ejtm.2018.7827).
This localized overload stimulates greater protein synthesis and muscle fiber hypertrophy in the upper arm, reflected as increased flexed arm circumference, but does not translate to enhanced strength across the six lifts (10.4081/ejtm.2018.7827).
Evidence from Studies
Supporting (1)
Community contributions welcome
Does the addition of single joint exercises to a resistance training program improve changes in performance and anthropometric measures in untrained men?
Contradicting (0)
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