Prevention and Rehabilitation of Hamstring Strain

Introduction

In Taiwan’s middle-distance running and marathon circles, hamstring strains are more commonly seen in runners performing sprint training or speed intervals, and they are also the most recurrent injury among all sports injuries. Literature reports show that previously injured runners have a re-injury rate as high as 30–40%. Understanding proper assessment methods and rehabilitation strategies is crucial to avoiding the cycle of repeated injury.

Anatomy and Function

The hamstring muscle group consists of three muscles: the semimembranosus, semitendinosus, and the long head of the biceps femoris. These three muscles cross both the hip and knee joints and play the following roles during running:

• Late swing phase: Eccentric contraction (rapid lengthening) to decelerate the forward swing of the thigh
• Just before ground contact: Transition to eccentric contraction, bearing extreme tension
• Push-off phase: Assists hip extension, providing propulsive force

This “lengthened-then-contracted” eccentric working pattern is the root cause of strain injuries.

Injury Grade Assessment

Ischial avulsion fracture: More common in adolescents, when the ischial tuberosity apophysis has not yet fused; forceful contraction may pull off a bone fragment, requiring X-ray confirmation.

Acute Phase Management (Days 1–3)

PEACE & LOVE Principles (Replacing the Old RICE)

• P (Protection): Protect the injured area, reduce vigorous movement, but complete immobilization is not necessary
• E (Elevation): Elevate the affected limb to reduce swelling
• A (Avoid anti-inflammatory): Avoid anti-inflammatory medications (including NSAIDs) during the acute phase, as initial inflammation is a necessary stage of repair
• C (Compression): Use elastic bandages or compression tights to control swelling
• E (Education): Understand the injury and set reasonable recovery expectations

The later phase enters the LOVE stage:

• L (Load): Early appropriate loading to avoid prolonged immobilization
• O (Optimism): A positive mindset aids recovery
• V (Vascularisation): Non-impact aerobic exercise (swimming, cycling) promotes blood flow
• E (Exercise): Perform rehabilitation exercises according to grade

Graded Rehabilitation Plan

Early Stage (Weeks 1–2)

• After normal walking is restored, add light stretching (pain < 3/10)
• Isometric contractions: Prone knee flexion at 30 degrees, hold for 5 seconds against light fixed resistance, 5 sets total
• Water running: Perform running movement patterns in a reduced-gravity environment

Middle Stage (Weeks 3–6)

1. Nordic Hamstring Curl — currently the most evidence-based training for preventing recurrence:

   • Kneeling position with heels anchored, slowly lean forward (eccentric) until falling, then catch with hands
   • Start with 5 reps per set, increase weekly, target 3 sets × 12 reps
   • Studies show it can reduce the future risk of hamstring strain by 50%

2. Romanian Deadlift: Hinge forward from the hips, feeling the hamstrings stretch, 3 sets × 12 reps

3. Prone Leg Curl: Using a machine or resistance bands, start with both legs then progress to single leg

Late Functional Training (After Week 6)

• Running technique drills: High knees, butt kicks, A-Skips, B-Skips
• Acceleration runs: Straight-line acceleration over 40m, initially limited to 70% of maximum speed, increasing by 10% each week
• Agility ladder drills: Direction changes to simulate the acceleration/deceleration demands of racing

Return-to-Running Criteria

Before performing speed work, the following tests must be passed:

• Single Leg Bridge: 15 reps, pain-free
• Nordic Hamstring Curl: Able to complete more than 5 reps, with strength asymmetry between injured and healthy sides < 10%
• 15-minute jog: Pain < 2/10, with no worsening the following day

Practical Prevention Recommendations

1. Nordic hamstring curls twice per week are currently the most evidence-based prevention strategy and should be incorporated into routine strength training
2. Warm up thoroughly before speed training: Include dynamic stretching and 4–5 progressive acceleration runs (50%→70%→90%) to gradually activate the muscle group
3. Avoid speed training in a fatigued state: Only perform interval runs after adequate recovery
4. Balance training volume and intensity: Do not increase both mileage and speed training within the same week

Conclusion

The high recurrence rate of hamstring strains stems primarily from two causes: returning to running too early and lacking targeted eccentric strengthening training. As long as Nordic hamstring curls are incorporated into the rehabilitation plan and return-to-running criteria are strictly followed, the vast majority of runners can safely return to the track and run more steadily than before the injury.

Related Reading

• Hamstring Strain in Basketball Players: An Analysis of Explosive Power Injuries
• Hamstring Strain Grading and Return-to-Running Timeline: The Most Complete Recovery Map After Muscle Tears
• Hamstring Injury Prevention: The Complete Protection Guide Every Runner Must Learn
• Hamstring Strain Rehabilitation: Research on the Protective Effects of the Nordic Hamstring Exercise