Is the patient performing the sit‑up correctly, given that he can only rise halfway before his pelvis lifts off the ground?

Sit-Up Performance Assessment

The patient is performing the sit-up incorrectly if his pelvis lifts off the ground at the halfway point, as proper sit-up technique requires the pelvis and lower back to remain flat against the surface throughout the movement to avoid potential hip or pelvic injury.

Proper Sit-Up Positioning Requirements

The correct sit-up position demands specific anatomical alignment that your patient is not maintaining:

• The pelvis must remain in contact with the ground throughout the entire movement 1
• The lumbar spine should be flattened against the surface, with hips and knees flexed to 90° to reduce physiological lumbar lordosis 1
• The patient should lie supine with legs straight initially, then position with knees bent and feet flat to maximize intervertebral spaces 1
• Arms should be positioned at the sides of the body or crossed over the chest, not pulling on the neck 1

Why Pelvic Lift Indicates Incorrect Form

When the pelvis lifts off the ground during a sit-up, this signals several biomechanical problems:

• Hip flexor dominance is compensating for weak abdominal muscles, causing the pelvis to rotate anteriorly and lift 2, 3
• The movement becomes a hip flexion exercise rather than true trunk flexion, defeating the purpose of abdominal strengthening 2
• This faulty movement pattern places excessive stress on the lumbar spine and hip joints 3, 4
• Pelvic rotation during the movement indicates loss of proper intra-abdominal pressure regulation 4

Correction Strategy

Instruct the patient to perform a modified crunch instead of a full sit-up:

• Have the patient lie supine with knees bent at 90° and feet flat on the ground 1
• Place a foam block or cushion under the knees to help flatten the lumbar lordosis 1
• Instruct the patient to lift only the shoulder blades off the ground (not coming up halfway) while keeping the pelvis completely flat 1
• The patient should focus on "curling" the trunk rather than "sitting up" 4
• Monitor that the lower back and pelvis maintain constant contact with the surface throughout the movement 1

Common Pitfalls to Avoid

• Do not allow the patient to continue the current technique, as repeated pelvic lifting can worsen hip and back injuries 1
• Do not have the patient pull on the neck or head, which increases cervical strain without improving abdominal engagement 1
• Avoid having the patient perform full sit-ups until core strength improves sufficiently to maintain pelvic stability 4
• Do not progress the exercise until the patient can perform 15-20 repetitions of the modified crunch with perfect form (pelvis flat throughout) 4

Progressive Exercise Modification

Once the patient masters the modified crunch with stable pelvis positioning:

• Progress to longer holds at the top position (3-5 seconds) while maintaining pelvic contact 4
• Add resistance gradually by crossing arms over chest, then placing hands behind head 1
• Only advance to fuller range trunk flexion when the patient demonstrates consistent ability to keep pelvis flat 2, 4
• Consider addressing hip flexor tightness and weakness in hip extensors/abdominals that may be contributing to the compensatory pattern 4