The sharp, stabbing pain of a muscle injury isn't what you might expect while stretching — but if you force a stretch too far or too fast, it can happen. The good news is that a few "best practices" for stretching can help you avoid unexpected hamstring pain or injuries.
Wait — Stretching Can Hurt Me?
If ever there were a fitness activity that's considered benign, it's stretching. But surprise: It is possible to stretch to the point of a muscle strain or, as it's more commonly known, a pulled muscle.
This can happen to any of your muscles, but there are a couple of reasons why the hamstrings — the big, meaty muscles in the backs of your thighs — might be more susceptible. The first is that, as Harvard Health Publishing points out, the modern-day habit of sitting for prolonged periods often leaves your hamstrings "continually overworked and overloaded," pulling double duty to make up for the chain reaction of weak glutes and tight hip flexors that sitting can produce.
The experts at Harvard Health go on to explain that when your hamstrings are so tight and overworked, they can be more easily injured or strained. That doesn't mean you shouldn't stretch your hamstrings — but you should follow a handful of best practices that will help you make sure the stretch time helps your hamstrings instead of hurting them.
The other reason it's so depressingly easy to pull your hamstrings when you stretch them? In many ways they're the canary in the coal mine of physical inflexibility. Overly tight hamstrings can have a noticeable effect on everyday movements as simple as lifting your legs to put on socks or to climb up a flight of stairs, which in turn makes it easier to accidentally push yourself to the point that your hamstring stretches end in injury.
Stretching is just one part of the process to restore muscular balance. You also need to strengthen your weak muscles and stretch other tight muscles — for example, your hip flexors, which oppose the glutes and tend to tighten when you sit a lot. Restoring muscular balance or building hamstring flexibility can take weeks or months, so it's worth consulting a fitness or medical professional to be sure you're focusing your efforts correctly.
How to Stretch Safely
So, what are the best practices to help you avoid that sharp pain in a hamstring when stretching? It might help to think of them as antidotes to the most common errors in stretching.
Error: Stretching cold muscles.
The antidote: Warm up before you stretch your hamstrings, just as you'd warm up before practicing any other component of fitness. That generally means doing five to 10 minutes (or more) of gentle physical activity before you stretch. Or, keep things simple and do your stretching workout after a cardio or strength-training workout, when your muscles are already warm. That increased body temperature and circulation help reduce your risk of injury while stretching.
Error: Stretching too far, too fast.
The antidote: Take your time and ease your way into the stretch, holding it at the point of mild tension in your muscle — not pain. You're going to be there for a while, anyway: The Mayo Clinic recommends holding each stretch for 10 to 30 seconds, and repeating the stretch a total of three to five times. Don't forget that if you're stretching one side at a time, as is commonly the case for hamstrings, you must stretch the other side too.
Error: Bouncing at the limit of your stretch.
The antidote: Relax into the stretch and, again, hold it — no bouncing! — at the point of tension but not pain. Help yourself relax by focusing on your breath. Breathe deeply, or at least normally, while you're in the stretch. If the stretch is painful enough that you can't breathe normally you're hurting your body instead of helping it. Perhaps counterintuitively, you'll progress more quickly if you ease off a bit.
Read more: The 8 Best Stretches for Your Legs
More About Muscle Strains
If you experience a sharp pain in a hamstring when stretching, there's a good chance that you've simply pushed yourself too far or too fast and managed to strain your muscles. After all, as MedlinePlus points out, common causes of muscle strains line up with the most common errors in stretching too: Not warming up properly, doing too much physical activity, or — just to add insult to injury — having poor flexibility.
Aside from that sharp pain in your muscle, other potential symptoms of a muscle strain include tenderness, redness or bruising, swelling, and difficulty moving the muscle. In more severe strains, you might also hear a pop from the muscle or the tendons that attach it to your bones.
MedlinePlus also details the ideal first aid for a hamstring strain. It begins with immediate application of ice for 10 to 15 minutes every hour during the first day; wrap the ice in a cloth instead of applying it to your bare skin. They recommend icing every three to four hours for the second and third days after your injury. After that, either heat or ice might be helpful.
You should also rest your pulled hamstring for at least a day, and try not to use it until the pain has gone away. Once the pain has diminished, they recommend gently stretching the muscle as a way to return to activity.
Sometimes You Need a Doctor
As the Mayo Clinic points out, mild muscular strains can be treated at home. However, the clinic —and numerous other health authorities — also advise seeing a doctor if your symptoms worsen despite treatment. Letting a professional check your hamstring tear diagnosis is especially important if the pain becomes intolerable or is accompanied by numbness or tingling, all of which can signal a more serious injury.
Once you've recovered from your hamstring injury, exercises to stretch and strengthen your legs can help prevent a recurrence. Ideally, a physical therapist or other rehabilitation professional should be involved in this, to help you diagnose and treat any other muscle tightness or imbalance before it causes more problems.
Here's one last piece of food for thought: If you didn't actually injure your hamstrings while stretching, you might have simply stretched enough to uncover an injury that already existed. That's not as far-fetched as it sounds, because the human body is very good at compensating for weakness or injury — which is why muscular imbalances can be so problematic.
If you can't gently stretch your way out of that tight or painful muscle, it's best to consult a medical professional for a diagnosis and treatment plan.