The Claim
Resistance training performed at long and mixed muscle lengths increases the cross-sectional area of the elbow flexors in recreationally trained adults.
What the research says
Supports is higher
Support is ahead, but a single strong opposing study can change this.
These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.
Doing resistance exercises with the elbow muscles stretched out or in varied positions leads to a measurable increase in the size of the elbow flexor muscles in people who regularly work out but are not elite athletes.
See the scientific wording
Resistance training at long and mixed muscle lengths both increase elbow flexor cross-sectional area in recreationally trained adults.
When muscles are stretched under load, the fibers and surrounding structures experience increased tension, which triggers chemical signals that tell the muscle to build more protein. At the same time, when blood flow is restricted or when muscles work hard without heavy weights, waste products build up inside the muscle, which also sends signals to make more protein. These signals turn on a key system that boosts the production of muscle proteins, leading to thicker muscle fibers over time, especially in areas that are stretched the most.
What the research says
3 studiesDoing bicep curls with your arm fully stretched out or moving through a full range of motion helped make the elbow muscles bigger in people who already work out — even partial curls worked, but full curls gave a little extra growth.
This study found that doing arm curls with your arm stretched out or bent out led to similar muscle growth in the biceps, even when using lighter weights with a special band to restrict blood flow. So yes, stretching your muscles during exercises can help them grow, just like regular workouts.
Study: Mixing Up Muscle Lengths: The Effects of Training at Different Muscle Lengths in the Elbow Flexors
This study found that doing bicep curls with your arm stretched out, or doing a mix of stretched and bent-arm curls, both made your biceps bigger — so both ways work just fine.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 3 supporting studies
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.