Trunk flexor strength testing is performed how?

Trunk flexor strength testing is performed how?

• A. Supine, perform partial trunk flexion (sit-up/crunch) against resistance with pelvis stabilized.
• B. Prone, extend the trunk against resistance at the lower back.
• C. Seated, bend the trunk to the side against resistance at the hip.
• D. Standing, perform full sit-up against resistance.

Answer: (A)

Isolating trunk flexor strength requires a position that prevents the hip flexors from helping and uses a limited range of motion. Lying on the back with the pelvis stabilized stops the pelvis and hip joints from tipping or lifting, so the effort comes mainly from the abdominal muscles. A partial trunk flexion, like a crunch, is used instead of a full sit-up because it challenges the abdominal muscles without heavily involving the hip flexors or using momentum. Resistance is applied to the upper trunk while the pelvis stays fixed, providing a clearer measure of how strong the trunk flexors are.

Isolating trunk flexor strength requires a position that prevents the hip flexors from helping and uses a limited range of motion. Lying on the back with the pelvis stabilized stops the pelvis and hip joints from tipping or lifting, so the effort comes mainly from the abdominal muscles. A partial trunk flexion, like a crunch, is used instead of a full sit-up because it challenges the abdominal muscles without heavily involving the hip flexors or using momentum. Resistance is applied to the upper trunk while the pelvis stays fixed, providing a clearer measure of how strong the trunk flexors are.