How do you screen for hamstring risk?

I got a question recently from a coach who had several athletes all carrying hamstring injuries, none of whom he'd worked with previously. He wanted to know what testing he could do at the start of a new block to flag these issues before they became a problem.

I shared some thoughts with him directly, and figured it was worth expanding on here.

The first thing worth getting clear on is what you're actually screening for. Hamstring injury tends to get framed as a strength problem. That framing is a bit incomplete.

A more useful way to think about it is capacity versus demand. At maximum velocity, the hamstring works eccentrically during late swing to decelerate the lower leg before ground contact. The forces involved at that moment are significant.

If the tissue isn't conditioned to handle that specific demand, something gives.

That reframe changes what you're looking for. You're not just asking whether their hamstrings are strong. You're asking whether they can handle what top-speed sprinting actually asks of them.

Multifactorial screening research consistently points to four areas worth covering: eccentric hamstring strength, broader posterior chain capacity, range of motion, and sprint mechanics. No single test tells you much on its own. The value comes from the pattern across all four.

Eccentric hamstring strength is the headline item. If you have access to a NordBord, great. Most coaches don't.

The practical version is partner-assisted Nordic curls, watching the lowering phase. Can the athlete control it, or do they collapse straight away? Is there a noticeable difference between legs?

Data on eccentric asymmetry shows that left-to-right gaps are a stronger risk signal than low absolute strength, so that's what you're mainly hunting for.

Posterior chain capacity follows the same logic. Single-leg bridges, RDLs, hip thrusts. A clear side-to-side difference across multiple exercises is a bigger flag than bilateral weakness on its own.

Range of motion often gets skipped because it feels like physio territory. A basic straight-leg raise takes two minutes per athlete. A meaningful left-to-right gap is worth flagging even when the absolute numbers look okay.

Then there's sprint mechanics, and this is where it gets interesting.

Coaches are genuinely best placed to assess this, and yet almost nobody frames it as part of a hamstring screen. Overstriding, excessive anterior pelvic tilt, very backseat mechanics, obvious asymmetry at top speed.

These patterns change how the hamstring gets loaded during late swing.

An athlete can have decent eccentric strength and still be running in a way that concentrates force on the tissue in a problematic way.

Sprint mechanics research has started to quantify this, with certain mechanical patterns associating with both past and future strains. Side-on video at near-max speed early in a season is worth more than coaches tend to give it credit for.

What you're building toward with all of this is a flag system, not a precise diagnosis.

An athlete who shows up weak in one area probably just needs more posterior chain work in their program. An athlete who flags across two or three areas is a different conversation.

Those guys get Nordics two to three times a week as a minimum, and a more controlled entry into high-speed work before they're thrown into full training volume.

This is where a lot of coaches get it backwards.

The instinct when you identify a fragile athlete is to protect them by pulling back on max-velocity exposure. The problem is that max-velocity sprinting is the primary eccentric stimulus for the hamstrings in a sprinting context. All the gym work in the world doesn't replicate what happens at top speed.

If an athlete never trains there, their tissue isn't conditioned to handle it when it counts.

The answer isn't less high-speed running. It's earning the right to do more of it gradually.

For an athlete with a history of tightness or a prior strain, I wouldn't start with true max-effort flying sprints. A few sessions of controlled buildups at around 70-80% over 40-50 meters comes first. Getting used to moving at higher speeds again, pain-free, with mechanics staying clean.

If that goes well, the next step is introducing a fly at submaximal effort. Something like a 20-30 meter relaxed buildup into a short fly zone at around 85-90% is a reasonable starting point. The goal at that stage is reintroducing the stimulus, not testing the ceiling.

From there you can progress either the intensity toward 100% or extend the fly distance from 10 to 15 to 20 meters. Not both at once.

The criteria for moving forward stay the same throughout. No pain during or after sessions, mechanics staying consistent, strength looking roughly even side to side. If any of those are off, hold where you are. No arbitrary timeline, just those three gates.

A short battery at the start of a block covering eccentric strength, posterior chain, range of motion, and mechanics at speed gives you enough to know who needs extra attention before the problems show up.

Better to find out in week one than halfway through a competitive block when it actually matters.