The Claim
In male bodybuilders, the rectus femoris muscle exhibits greater stiffness in the proximal region during maximal isometric knee extension when the hip is in an extended position (0° or 40° of flexion) compared to when the hip is flexed at 80°, specifically at a knee flexion angle of 30°, indicating regional mechanical differences in muscle activation influenced by hip joint position.
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.
When male bodybuilders flex their knees at a 30-degree angle, the upper part of a specific thigh muscle gets stiffer if their hips are straighter, suggesting how stretched the hip is can change how the muscle works.
See the scientific wording
In male bodybuilders, rectus femoris muscle stiffness during maximal isometric knee extension is greater in the proximal region when the hip is extended (0° or 40° flexion) compared to when it is flexed at 80°, specifically at a knee flexion angle of 30°, suggesting regional mechanical differences in muscle activation based on hip position.
What the research says
1 studyThe study found that when male bodybuilders push their knees straight with their hips extended, the top part of a specific thigh muscle gets stiffer than when the hip is bent more, which matches the claim.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.