The Runner’s World Guide to Common Running Injuries: Hamstring Strain

When you think of hamstring injuries, you might picture a sprinter stopping short, clutching the back of their thigh. Hamstring pain isn’t always that dramatic. Sometimes, for many runners, it develops slowly as fatigue builds and the muscles become overloaded.

In The Runner’s World Guide to Common Running Injuries, host Winnie Yu, PT, DPT, CSCS, along with other medical experts helps you better understand what's causing pain in your hammie. It’s not always serious enough to make you stop, but it can slow you down or be a hidden reason you missed that PR.

Here’s how to treat it appropriately—so you recover faster, return to running safely, and reduce your risk of another setback.

In The Runner’s World Guide to Common Running Injuries: Hamstring Strain, we’ll teach you:

• The difference between acute and chronic hamstring strains
• Common causes and risk factors behind hamstring pain, from the sudden to the gradual
• Rehab exercises that safely rebuild hamstring strength, along with the mistakes you can make when trying to
• The timeline for returning to running, depending on the severity of your hamstring pain
• Daily habits that help prevent future hamstring strains

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Understand the Injury

Hamstring strains usually fall into two categories.

Acute Hamstring Strain

• Happens suddenly during sprinting, hill repeats, or explosive efforts
• Commonly caused by a sudden increase in power or intensity that your hamstring isn’t quite ready for
• Acute strains can take a short amount of time to recover from, but can also be full-blown tears that will keep you sidelined for much longer

“It’s going to feel like someone kicked you really hard in the back of the thigh, and yet no one was there to kick you,” says John Vasudevan, MD. “And it’s going to be very difficult to run or let alone walk for much longer without stopping. This kind of injury is definitely a sign that the run is over, and you need to give yourself adequate time for healing.”

Chronic Hamstring Strain

• Develops gradually over weeks or months, to the point where you may not notice anything until it suddenly feels painful
• Caused by repeated overload and cumulative fatigue
• The tiny muscle tears caused by a strain create stiffness and discomfort
• May slow you down without forcing you to stop running
• Often occurs when fatigued glutes shift more workload onto the hamstrings

“Usually, it’s a matter of cumulative fatigue and insufficiency to create enough power out of your gluteus maximus, which is that big butt muscle in the back, because that is the main driver of hip extension,” says John Vasudevan, MD. “And when that starts to fatigue, your hamstrings start to take on too much load. And that’s when you start experiencing more chronic, insidious pain.”

Underlying causes of hamstring strains

• Introducing speedwork too quickly
• Adding hill training too aggressively
• Fatigued glute muscles

How Serious Is It?

How your pain behaves during and after a run can help you determine what to do next.

🟢 Green Flag

• Mild soreness or tightness
• Symptoms developed gradually
• May improve with modified training and early strengthening

🟡 Yellow Flag

• Persistent pain during or after running
• Swelling or noticeable weakness
• Difficulty producing normal power

🔴 Red Flag

• Sudden sharp pain that immediately stops your run
• Significant bruising or swelling
• A noticeable gap or defect in the muscle
• Inability to continue running or walking comfortably
• Seek medical evaluation promptly

It Might Not Be Your Hamstring If...

• You also have lower back pain
• Pain radiates into the calf or foot
• You experience numbness or tingling

These symptoms may indicate the issue is coming from your spine rather than your hamstring and should be evaluated by a physician.

Recover and Return to Running

“Even though a hamstring strain often feels like it needs a stretch, stretching too early can actually slow your recovery. Early on, focus on controlled activation and strengthening instead,” says Yu.

Your rehab priorities should include gently activating your hamstrings while building strength.

Prone Hamstring Curl

Elevated Bridge

Single-Leg Bridge

❌ Common Recovery Mistakes:

• Not starting on soft, flat terrain
• Adding speedwork to your training too fast. Ease into runs and take them easy until the hamstring is feeling strong
• Increasing mileage too quickly when returning to running Stay Healthy and Run Stronger

Many exercises used during your rehab program can also become part of your prehab routine. Along with strengthening your hamstrings, glutes, and quads (and overall your lower body), you can prioritize mobility before harder efforts by warming up before every run and doing a proper cooldown.

Training habits to reduce recurrence of hamstring strains:

• Progress hills gradually
• Introduce speedwork slowly
• Increase mileage conservatively (think of the 10 percent rule)
• Break up long periods of sitting if you’re at a desk most of the day with walk breaks or easy drills to add mobility to your day

Ready to build a stronger, more resilient running routine?

Whether you're beginning to run or you're training for that next marathon, the Runner’s World Guide to Common Running Injuries will help you spend less time sidelined and more time doing what you love. You’ll learn how to recognize the signs of common running injuries, understand their causes, and determine when you can safely modify your training versus when it’s time to seek medical care. This holistic program is available exclusively to Runner’s World+ members and launches on October 6!

Brian Dalek

Director of Content Operations Runner’s World & Bicycling

Brian has spent 15 years focused on creating compelling news, health, and fitness content—with a particular interest on enthusiast activities like running and cycling. Along with producing The Runner’s World Show podcast, Brian oversees video content series like How to Master the Marathon and The Bicycling Guide to Weight Loss. He’s coordinated coverage of major events like the Paris Olympics, Boston Marathon, New York City Marathon, and Tour de France, with an eye toward both the professional race and the engaging stories readers love.