Rectus Femoris
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A 2-joint quadriceps muscle that flexes the hip and extends the knee.
Detail
The rectus femoris is a 2-joint muscle. It flexes the hip joint and extends the knee joint. It makes its best contribution to hip flexion when the knee is maintained in a flexed position. It is a powerful extensor of the knee when the hip is extended, but weak when the hip is flexed. As one of the four quadriceps, it is involved in squats and leg extensions; in the 45-degree leg press there is little involvement of the rectus femoris.
Key facts
- 2-joint muscle: flexes the hip and extends the knee.
- Best hip-flexion contribution when the knee is flexed.
- Powerful knee extensor when the hip is extended; weak when the hip is flexed.
- Little involvement in the 45° leg press.
Connections
- Hip Flexors — a primary hip flexor.
- Quadriceps — one of the four quadriceps.
- Two-Joint (2-Joint) Muscles — exemplifies 2-joint-muscle behavior.
Sources
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