Hamstring Injuries: Why They Really Keep Coming Back and How to Fix Them

Hamstring strains are the annoying neighbour of the injury world. They show up uninvited, ruin your week, disappear… then show up again right when you start feeling confident. If you’ve ever grabbed at the back of your thigh mid-run, you already know the cycle. What most people don’t know is that hamstring injuries are not just “common”. They are one of the most stubborn injuries in sport, with up to thirty percent coming back in the same season.

And here’s the uncomfortable truth.
Most hamstrings reinjure because people return to sport way too early. Not because they’re reckless. Not because they don’t do their exercises. But because the entire system of how we clear hamstring injuries is built around how good you feel, not how healed your muscle actually is.

A major review in Sports Medicine reveals the problem clearly. It turns out your hamstring can pass every test, feel incredible, look perfect on the field and still be nowhere near biologically healed. That gap is where reinjuries explode.

The controversial truth: pain lies

We’ve all been taught that when the pain goes away, you're good to go. It feels logical, but the research shows it’s misleading. The study showed that athletes usually return between eleven and twenty five days after a hamstring strain. The issue? Inside the muscle, everything is still a construction site.

Even when pain settles and strength looks normal, the microscopic scar tissue in your hamstring is still weak, immature and not yet structurally ready for high speed movement. In fact, the tissue fibres do not even start forming proper, load-bearing strength until around three weeks post-injury. That means people are returning to sport at the exact moment their muscle tissue is least prepared to handle load.

This is why a quarter of all recurrences happen in the first week back.

So if you’ve reinjured your hamstring, no, it probably wasn’t your warm-up. It wasn’t your footwear. It wasn’t the universe punishing you. Your muscle simply wasn’t ready.

Why your hamstring fails in the exact same place

Another uncomfortable point. Reinjuries don’t just happen again. They happen in the exact same few centimetres of tissue almost every time. The review showed that when scar tissue forms, the collagen fibres are poorly organised for weeks. The glue holding the healing muscle together is more like soft putty in the first three weeks. Then we go sprinting, kicking or lifting and wonder why it gives way.

If you’ve ever felt your hamstring “pop” in the same spot twice, this is why.

The rehab industry won’t love this part

The authors of the review make a bold recommendation. They say that for grade one and grade two hamstring strains, nobody should return to sport before four weeks.
Not “if you feel good”. Not “if your strength is symmetrical”. Not “if you can sprint pain-free”.

Four weeks. Minimum.
Because that is how long it takes for the tissue to reach a stage where it can actually handle load.

Return to Play After a Hamstring…

You don’t need to sit around for four weeks. You should be training hard, rebuilding strength and progressing safely. But the idea that a hamstring is ready at two weeks is not just outdated. It is biologically impossible.

So how do you ACTUALLY fix your hamstring for good?

Here’s the straight truth.

1. Stop rushing the return.
If your last hamstring rehab was fast tracked, you’ve already found the problem.

2. Build real strength, not “gym strength”.
Hamstrings need high force, eccentric strength under long muscle lengths. Nordics, RDLs, hip hinges, and progressive sprinting get results. Floppy band curls don’t.

3. Rebuild your sprint mechanics.
Most strains happen at high speed. If your rehab didn’t include progressively faster running, you weren’t prepared.

4. Challenge the hamstring in lengthened positions.
This is where most people avoid load, yet it’s where the muscle fails.

5. Fix the ecosystem around the hamstring.
Weak glutes, stiff lower backs and poor pelvic control all force the hamstring to work overtime. If you ignore them, the cycle repeats.

The real takeaway

If you want your hamstring injury to be the last one you ever have, you need a rehab approach that respects the biology, not just the symptoms. The research is very clear. The muscle will feel good long before it is actually strong enough. That’s why so many people reinjure. Not because they aren’t dedicated. But because no one told them the truth about how slow muscle tissue heals.

When you train smart, load progressively and give the tissue its full biological healing window, your hamstring becomes resilient again. You can run fast, jump high and accelerate hard without that little voice in the back of your mind saying “please don’t tear again”.

And once you understand the true timeline of muscle healing, you realise something important.

Your hamstring was never the problem. The timeline was.

Pieters D, Wezenbeek E, Schuermans J, Witvrouw E. Return to Play After a Hamstring Strain Injury: It Is Time to Consider Natural Healing. Sports Medicine. 2021;51:2067–2077. https://doi.org/10.1007/s40279-021-01494-x