Your hamstrings are not the strongest muscles in your legs, but they play a major role in your ability to move. As a result, hamstring injuries have sidelined more than one professional athlete for an entire season.

So, what are hamstrings?

Your hamstrings are actually a group of three muscles located on the back of your leg. This trio, which includes the semitendinosus, semimembranosus and the biceps femoris muscles, run from the top of your thigh to your knee joint. They play a part in posture, pelvic positioning, knee support and leg movement.

How do hamstring injuries occur?
When you’re healthy, every action of the muscles in the front of your leg (the quadriceps) creates an opposite reaction in your hamstrings. These two muscle groups work in unison to extend and contract allowing you to bend your knees, straighten your hips and rotate your legs. Your hamstrings also work in tandem with the quadriceps to stabilize your pelvis and support your knees.

There is a delicate balance of power between the quadriceps (quads) and the hamstrings. It’s natural for the quads on the front of the leg to be stronger than the hamstrings. The strength of the hamstrings should be between 50 to 80 percent of the quad strength, with 70 being the optimum goal.

But many people have a strength imbalance. Their hamstrings are too weak to support the action of the quads. This strength deficit can happen for many reasons. Two of the most common activities that disrupt the balance of power are running and sitting.

When the quad-hamstring strength ratio becomes unbalanced, people may experience low-back pain and an increased risk for hamstring strains or tears.

Are you at risk for a hamstring injury?

To see if your hamstrings are weak or tight, bend over and touch your toes. If your toes and fingers do not meet, you may have tight or weak hamstrings.

Your hamstring muscles are susceptible to both, overuse injuries and acute or sudden injury. Your hamstring can “pull” while you are running, kicking, rapidly changing direction or simply walking down the steps. When the injury occurs, many people have described feeling a sudden pain that may be accompanied by a popping sound.

Typically, hamstring injuries are graded based on the severity of the damage to the muscle-tendon group.

Grade 1 – The hamstring injury causes minor pain and inflammation, but allows for nearly normal movement. The hamstring muscle is stretched but not torn.

Grade 2 – The hamstring muscles may have a slight tear. A person experiencing a grade 2 hamstring injury feels significant pain. He or she will most likely limp and feel pain when stretching or straightening the injured leg. The injured area also may be tender to the touch.

Grade 3 – The hamstring has a significant or complete tear. A grade 3 hamstring injury causes tenderness, severe pain and swelling. A person who has a major injury may not be able to walk without the assistance of crutches. He or she should call a medical or orthopaedic specialist for treatment.

In some cases, a small piece of bone will be pulled off the pelvis or knee as the hamstring tears. This type of tear is known as an avulsion injury. If the bone fragment remains close to the larger bone, it will heal without surgical treatment. If the bone fragment is displaced it may require surgical repair.

According to a study published in the May 2016, issue of PLoS One, more than 88 percent of hamstring injuries are sports-related, with 50 percent of those occurring in professional or competitive athletes.

But, you don’t have to play sports to experience a hamstring injury. Another 11.1 percent of hamstring injuries were related to minor falls. In this non-sporting category, young children and older women were more susceptible to a grade 2, grade 3 or avulsion injuries. Early research suggests these injuries may be related to low bone mineral density, however, more conclusive evidence is needed.

An ounce of prevention is worth weeks of recovery

While you may not be consciously aware of your hamstrings while you chase a tennis ball, block a shot or make a tackle, conditioning and strength training can help you prevent injury.

Warm-up before play, practice or your workout

Warming up and stretching your hamstring muscles can help you prevent hamstring injuries. Spend the first 5 or 10 minutes of your workout walking around the block or marching in place to warm your legs. Then bend over and stretch for your toes. Don’t bounce, just stretch gently. Starting your workout with warm and supple hamstrings will help you avoid strains and tears.

Keep the strength of your leg muscles in balance

According to a 2001, article published in the Journal of Athletic Training, the normal strength ratio between the quads and the hamstrings should be 50 to 80 percent. If the quads are stronger than the hamstrings, they force the hamstrings to respond to movements faster and more intensely. If the hamstrings movements cannot keep up the motion of the quadriceps, they can snap and tear like a rubber band that has been stretched too far.

A well-rounded workout routine focuses on a developing a strong core with strong, supple and well-balanced leg muscles. Strengthening your glutes and calves can have a positive influence on the function of your hamstrings.

Choose the right shoes

High heels or elevated heels on men’s shoes change the alignment of your feet and lower legs, which can tighten your hamstring muscles. This misalignment can result in low-back pain.

If you choose to wear higher heels, make it a point to stretch your hamstrings a few times each day. Stand on a step holding the handrails. Place the balls of your feet firmly on the edge of the step. Slowly lower your heels toward the floor, being careful not to bounce. Hold this position for 10 seconds and return to the starting position. Repeat 12 times. This exercise will help loosen tight hamstrings.

Take note of your hip flexors

Sitting for hours at a time can lead to tight hip flexors which hinder hamstring movement. If your job requires sitting for most of your day, make a point to stand up at least twice each hour. Standing or walking for a minute or two every half hour provides much needed circulation to your legs and works your hip flexors.

Keeping your hamstrings supple and strong can help you stay active.

If you experience a hamstring strain, remember to RICE it. If the pain lasts longer than 48 hours, you should talk to your primary care provider or an orthopaedic specialist.