Why do I keep straining my hamstrings?

Recurrent hamstring strains usually involve limited eccentric hamstring strength, high sprint exposure without adequate preparation, previous injury, and fatigue. Eccentric work such as Nordic hamstring curls plus a graded return to high-speed running is the best-supported approach. See a clinician for a current injury.

The main risk factors

• Previous strain: The strongest single predictor of a future one, largely because rehabilitation is often stopped too early.
• Low eccentric strength: The hamstrings work hardest while lengthening in late swing phase, decelerating the shin before foot strike.
• Insufficient high-speed exposure: Hamstrings that rarely see maximum velocity are unprepared when a match demands it.
• Fatigue: Most strains occur late in matches or late in sessions.
• Sudden load spikes: A large jump in sprint volume after a break is a classic setup.

What has the best support

Eccentric hamstring strengthening, particularly the Nordic hamstring curl, has good evidence behind it for reducing hamstring injury rates. Start with assisted partial range, two sessions a week, low volume, and build gradually. It produces considerable soreness at first, so introduce it well away from competition.

Build the other side too

Add Romanian deadlifts and single-leg Romanian deadlifts for strength through range, and 45-degree back extensions for lighter posterior chain volume. Include hip flexor and trunk work, since pelvic control affects the load the hamstrings carry.

Expose yourself to speed regularly

Regular, controlled high-speed running is protective rather than dangerous. One or two short sprint exposures a week, built up gradually and performed fresh, keeps the tissue prepared. Removing sprinting entirely because you are worried about strains tends to make the next one more likely.

Manage fatigue and load

Avoid large week-to-week jumps in sprint distance, and be cautious returning after a layoff. Sleep and nutrition both influence tissue tolerance.

Get proper rehabilitation

A current or recent strain needs assessment and a structured return-to-running programme from a physiotherapist. Returning as soon as it stops hurting is the most common reason strains recur. Related material is in Deceleration: Braking Mechanics, Eccentric Strength, and Injury Risk.