It depends on grade and location. A typical grade 1 returns to sport in 2 to 3 weeks. Grade 2 usually takes 4 to 8 weeks. Grade 3 complete tears sit at 3 to 6 months. The British Athletics Muscle Injury Classification (Pollock et al., BJSM 2014) added that intratendinous (type c) injuries are slower than myofascial (type a) injuries at the same apparent grade, so the MRI location changes the timeline. Time frames are useful for planning, but return is determined by meeting criteria, not by the calendar.

Sprinting or stretching injury, and does it matter?

It matters a lot. Askling described two patterns that behave very differently. Sprinting-type strains happen at high speed and usually heal faster. Stretching-type strains happen at long muscle length (high kick, hurdler's stretch, water skiing) and take significantly longer to settle. In the Askling 2013 trial, stretching-type injuries took nearly twice as long to return as sprinting-type on the same protocol. The history dictates how aggressive I am with end-range loading.

Why do hamstring injuries come back?

Two main reasons. First, returning to full pace before the tissue has rebuilt capacity at long muscle lengths. Second, dropping the eccentric work once the acute pain has gone. About 75 to 80 percent of recurrences happen at or near the original site, which points to the scarred region stays more mechanically vulnerable if the surrounding tissue is not loaded properly.

Do I have to do Nordic hamstring curls?

Strongly yes for anyone returning to running, kicking, or cutting sport. Van Dyk et al. (BJSM 2019) pooled 15 studies across 8,459 athletes and found inclusion of the Nordic in a prevention programme roughly halved hamstring injury rates. It is not a pleasant exercise, but the effect size is larger than almost anything else in the rehab toolbox.

When can I start running again?

When single-leg hop, isometric hamstring strength, and pain-free eccentric loading are symmetric. Running usually returns in phase two for most grade 1 and low-grade 2 strains. Start on flat ground at easy pace, short durations, and build volume before speed. Speed work is gated until late phase three.

Is stretching a good idea?

In the acute phase, aggressive end-range stretching usually delays healing, particularly for stretching-type injuries. Gentle range work and early eccentric loading do more for long-term length than static stretching. I rarely prescribe formal hamstring stretches in the early weeks.

Not for most straightforward strains. I use MRI when I suspect a proximal avulsion, when the injury is in-season for a high-level athlete and prognosis drives selection decisions, or when recovery is stalling and a structural cause needs to be ruled in or out. The JOSPT 2022 CPG considers imaging useful for prognostication in competitive athletes but not necessary for most rehab plans.

What if I feel it twinge again while running?

Stop the session that day and drop back one phase in the loading plan for 3 to 5 days. A twinge is data, not failure. Most often it means the next step in the progression was too big or the warm-up was too short. I reassess with isometric testing, pain-free range, and hop symmetry before resuming at the previous tolerated volume.

Hamstring Strains

Hamstring tears and chronic tightness

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The Science of Hamstring Strains

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Hamstring strains occur during eccentric contraction when the muscle is lengthening under load. The biceps femoris is most commonly injured, typically at the musculotendinous junction.

Conditions I commonly see alongside, or confused with, this one.

Proximal Hamstring Tendinopathy
Anatomically related
Both affect hamstring muscles; acute strains can lead to chronic tendinopathy
Groin Strains
Biomechanically linked
Both are common sports injuries with similar mechanisms and recovery approaches
Low Back Pain
Biomechanically linked
Hamstring tightness can contribute to lumbar spine stress and back pain

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Hamstring Strains

The Science of Hamstring Strains

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