How to stop tearing your hamstring

The one intervention with the strongest evidence

Eccentric hamstring strength training — principally the Nordic hamstring curl — has the best evidence base of any hamstring injury-prevention intervention. Petersen and colleagues' 2011 cluster-randomised controlled trial in men's soccer is the reference study, and it is the reason the Nordic curl appears in nearly every week of every running-sport program in Train Smart.

It reduces risk. It does not eliminate it. Anyone telling you a single exercise will stop you tearing a hamstring is overselling the evidence.

Why eccentric, specifically

A hamstring strain almost always happens in late swing phase of a sprint — the moment the leg is decelerating before the foot lands, when the muscle is lengthening under load. That is an eccentric action. Training the muscle concentrically, which is what a leg curl machine mostly does, trains a different thing.

This is also why the Nordic break-point test is a useful screen: it measures the exact quality that fails.

What a practical program looks like

• Nordic curls twice a week, 2–3 sets of 4–6 reps, lowering as slowly as you can control. Start assisted if you need to.
• Expect real soreness for the first two weeks. It settles. That is the adaptation, and it is why you introduce this in pre-season rather than in round eight.
• Progress by lowering further and slower before you progress by adding reps.
• Add hip-hinge strength — Romanian deadlifts, single-leg RDLs — for the other end of the muscle.
• Do not stop in-season. The protective effect goes away when the training does, and the season is when you need it.

The other half: exposure to speed

This is the part injury-prevention articles usually miss. A hamstring tears at high speed, and a muscle that never sees high speed in training is not prepared for it in a game. Athletes who do all their running at moderate pace and then sprint flat-out in a match are in the worst position of all.

Regular exposure to genuine top-speed running — short, fresh, fully recovered efforts — is protective. It is also the reason Train Smart's speed sessions specify full recovery and low volume rather than "sprint intervals": those are two different things, and only one of them exposes you to real top speed.

Load, and the sudden spike

Sharp week-to-week jumps in training load are associated with raised injury risk — the basis of the IOC consensus statement on load and injury. In practice that means the worst thing you can do after three quiet weeks is a very big week. More on managing that here.

What the evidence does not support

• Static stretching before a game as an injury-prevention measure. It does not have the evidence people assume it does.
• Foam rolling as a substitute for strength work. It may help how you feel; it does not make the muscle stronger eccentrically.
• Any single exercise as a guarantee. Injury is multifactorial — previous injury history remains one of the strongest predictors and you cannot train it away.