Do sit-ups and push-ups exacerbate femoral neck fractures in a young, physically active individual with a history of stress fractures or osteoporosis?

Sit-Ups and Push-Ups with Femoral Neck Fractures

Sit-ups and push-ups should be avoided during the acute healing phase of femoral neck stress fractures, but can be safely resumed once the fracture has healed and the patient has been cleared for return to activity, as these exercises do not directly load the femoral neck.

Understanding the Biomechanics

The femoral neck is primarily loaded through:

• Axial compression forces from weight-bearing activities like running, walking, and jumping 1, 2
• Tension forces on the lateral (superior) aspect during weight-bearing 1, 3

Sit-ups and push-ups are non-weight-bearing exercises that do not create significant direct loading forces on the femoral neck 1. These exercises primarily engage:

• Core musculature (sit-ups)
• Upper body musculature (push-ups)

Critical Context: Femoral Neck Fracture Severity

High-Risk Fracture Characteristics

Femoral neck stress fractures are particularly dangerous because they can progress to:

• Complete displacement requiring surgical fixation 1, 3
• Avascular necrosis of the femoral head 1, 3
• Delayed union or non-union 1, 3

Lateral "tension-type" femoral neck fractures are inherently unstable and prone to displacement, often necessitating percutaneous screw fixation 1, 3. These represent the highest risk category.

Medial "compression-type" fractures are lower risk but still require careful management with non-weight-bearing protocols 1.

Activity Modification Algorithm

During Acute Fracture Healing (First 6-12 weeks minimum)

Avoid ALL activities that involve:

• Weight-bearing on the affected limb 1
• Hip flexion against resistance (this includes certain sit-up variations that engage hip flexors)
• Any activity causing groin pain 4, 5

Safe activities during healing:

• Upper body resistance exercises in seated/supine positions (push-ups from knees or wall push-ups may be acceptable if no hip discomfort) 1
• Core exercises that do not engage hip flexors (planks, modified sit-ups with minimal hip flexion)
• The key criterion is absence of groin or hip pain during and after the activity 4, 5

Return to Activity Criteria

MRI grading predicts return to sport timing: for every 1-unit increase in MRI grade severity, time to full return increases by approximately 48 days 1. Trabecular stress injuries (like femoral neck) require longer recovery than cortical bone injuries 1.

Before resuming full exercise including sit-ups and push-ups:

• Complete resolution of groin pain 4, 5
• Radiographic or MRI evidence of healing 1
• Clearance from treating physician based on imaging and clinical assessment 1

Special Populations Requiring Extra Caution

Female Athletes with Triad Components

If the patient has any components of the Female Athlete Triad (low energy availability, menstrual dysfunction, low bone mineral density), they are at high risk for recurrent fractures 1:

• BMD Z-scores ≤-2.0 with clinically significant fracture history represent the highest risk category 1
• These patients require at least 1 year of non-pharmacological therapy (increased caloric intake, reduced training volume, addressing menstrual dysfunction) before return to full activity 1
• Stress fractures at trabecular sites like the femoral neck are considered high-risk and delay return to play 1

Patients with Osteoporosis

Young adults with osteoporosis can develop femoral neck insufficiency fractures even from normal daily activities 2, 6, 7:

• These patients require bone density optimization before resuming any exercise program 7, 5
• Vitamin D deficiency and poor nutrition must be addressed 5
• Even after clinical recovery from conditions like anorexia nervosa, heavy exercise like running carries increased fracture risk 8

Common Pitfalls to Avoid

1. Delayed diagnosis leads to bilateral progression: High index of suspicion is critical, as initial radiographs have only 30-70% sensitivity 1, 3, 5. If groin pain persists despite negative X-rays, MRI is essential 1, 4.

2. Premature return to weight-bearing activities: The femoral neck requires complete healing before resuming running or jumping activities 4, 6. Non-weight-bearing exercises like sit-ups and push-ups can typically be resumed earlier, but only if pain-free.

3. Ignoring underlying risk factors: Failure to address low bone density, nutritional deficiencies, or Female Athlete Triad components leads to recurrent fractures 1, 8, 5.

Practical Recommendation

For a young, physically active individual with a femoral neck stress fracture:

• Immediately cease all weight-bearing exercise including running, jumping, and prolonged standing 1, 6
• Sit-ups and push-ups can be cautiously attempted if they cause no groin or hip pain, starting with modified versions (wall push-ups, partial sit-ups)
• Monitor for any groin discomfort during or after these exercises—any pain indicates the activity should be stopped 4, 5
• Prioritize bone health optimization: ensure adequate calcium/vitamin D intake, address any menstrual irregularities in females, and consider bone density testing 1, 7, 5
• Follow-up MRI at 6-12 weeks to assess healing before progressing activity 1

The superolateral region of the femoral neck remains relatively weak even in active individuals because standard exercises primarily strengthen inferomedial regions 2. Therefore, even after healing, a graduated return to high-impact activities with ongoing monitoring is essential.