What is the recommended treatment regimen for an acute hip flexor strain?

Treatment Regimen for Acute Hip Flexor Strain

For an acute hip flexor strain, initiate immediate ice application, relative rest with protected weight-bearing, followed by a structured 6-week progressive strengthening program using elastic band resistance, advancing from 15 repetition maximum to 8 repetition maximum over the treatment period 1, 2.

Acute Phase Management (First 72 Hours)

The initial treatment follows standard acute strain protocols:

• Ice application to the injured area
• Immobilization of the hip flexor musculotendinous unit to prevent further tearing
• Protected weight-bearing as tolerated based on pain levels

This approach applies regardless of strain severity (first-degree minimal stretching, second-degree partial tear, or third-degree complete disruption), though the duration of this phase varies with injury severity 1.

Rehabilitation Phase (Weeks 1-6)

Begin structured strengthening at week 1-2 once acute pain subsides. The evidence strongly supports a specific 6-week protocol that produces a 17% increase in hip flexion strength 2:

Exercise Prescription Details

• Frequency: 3 sessions per week, 10 minutes per session
• Resistance: Elastic bands providing progressive overload
• Progression schedule:
  • Week 1: 15 repetition maximum (RM)
  • Weeks 2-5: Gradually decrease repetitions while increasing resistance
  • Week 6: 8 RM (heavier resistance)

Optimal Exercise Selection

Target hip flexion ranges of 30-60 degrees for maximal iliopsoas activation 3:

• High activation exercises (>60% MVIC): Active straight leg raises at 60° hip flexion, supine hip flexion with leg lifts
• Moderate activation exercises (40-60% MVIC): Mid-range straight leg raises at 45° hip flexion, trunk lifting from hip-flexed position
• Progression: Advance from closed kinetic chain → open kinetic chain → external load addition 3

Return to Activity Phase (Weeks 6+)

Once basic strength is restored, progress toward sport-specific demands 4:

1. Cardiovascular fitness restoration
2. Basic athletic movements (squatting, lunging)
3. Load tolerance training with progressive resistance
4. Sport-specific tasks: Running → high-speed running → cutting/twisting movements
5. Provocative position training at increasing speeds

Monitoring Treatment Response

Track progress using 4:

• Patient-reported outcomes: Copenhagen Hip and Groin Outcome Score (HAGOS) or International Hip Outcome Tool (IHOT)
• Physical measures: Hip range of motion, muscle strength testing, movement quality assessment, functional task performance

Critical Considerations

Common pitfall: Returning to sport too early before adequate strength restoration. Hip flexor injuries require significant rehabilitation time despite high return-to-play rates 5. The 6-week minimum strengthening period is evidence-based and should not be shortened.

Individualization factors: While the core protocol remains consistent, adjust the timeline based on:

• Strain severity (grade I vs II vs III)
• Patient's activity demands and goals
• Symptom response during progression
• Associated hip pathology (5-28% of hip flexor injuries occur with other hip conditions) 5

Surgery consideration: Third-degree complete disruptions may require surgical repair before initiating rehabilitation 1. This represents a small minority of cases but must be identified early through clinical examination and imaging.

The evidence supporting this structured approach is moderate quality, with the 6-week strengthening protocol derived from a randomized controlled trial showing substantial strength gains 2, and exercise selection guided by recent EMG studies 3. The acute management principles are well-established in sports medicine practice 1.