Hamstring Force and Stretch During Progressively Increasing Running Speeds and the Eccentric Phase of Resistance Training Exercises Commonly Used for Injury Prevention and Rehabilitation

Why It Matters

Understanding the specific force‑stretch demands of each exercise enables clinicians to progress patients safely and optimize training for injury prevention and performance.

Key Takeaways

• RDL yields highest hamstring force and stretch.
• Hip thrust produces less force than walking.
• Unilateral hamstring bridge matches sprint force, high stretch.
• NHE and slider give low stretch despite moderate force.
• Exercise selection aligns with rehab stages.

Pulse Analysis

Hamstring strains remain the most prevalent non‑contact injuries in sprint‑based sports, costing teams millions in lost performance. Traditional programming has relied on EMG activity or anecdotal load prescriptions, yet tissue adaptation is driven by the actual mechanical tension and elongation experienced by the musculotendinous unit. By integrating MRI‑derived muscle geometry with EMG‑driven modelling, the current research delivers the first comprehensive comparison of force and stretch across a spectrum of resistance exercises and progressive running speeds, offering a data‑rich alternative to guesswork.

The findings reveal a clear hierarchy of loading: the bilateral Romanian deadlift (RDL) imposes the highest normalized forces on the biceps femoris long head and semimembranosus, as well as the greatest stretch, exceeding even maximal sprint demands. Unilateral movements such as the hamstring bridge generate forces comparable to sprinting while still delivering substantial stretch, positioning them as ideal mid‑stage rehabilitation tools. Conversely, the hip thrust registers lower forces and stretch than even walking, making it suitable for early‑phase, low‑stress conditioning. The Nordic hamstring exercise and eccentric slider, despite moderate force outputs, produce the least stretch, suggesting a role in strength development without excessive tissue strain.

Practitioners can now map exercise selection to specific rehabilitation milestones: start with hip thrust for early tissue tolerance, progress through Nordic and slider for moderate loading, incorporate razor or eccentric hip extensions as athletes approach 75% of maximal running intensity, and reserve RDL or unilateral bridge for late‑stage or performance‑oriented phases. Future work should test these biomechanical prescriptions in longitudinal injury‑prevention trials and expand modeling to diverse populations and overground sprinting. The study’s rigorous methodology and actionable insights make it a valuable reference for sports medicine professionals seeking evidence‑based hamstring conditioning strategies.