Causes of a Pulled Hamstring

Forces more than 70% make the hamstring muscle more susceptible to an injury. This extra stress placed on the hamstring muscles and tendons can occur during: Active sports that require speed, power and agility (soccer, football, baseball, softball, basketball, rugby, tennis) or track & field activities that involve a lot of jumping, kicking, running and fast "stop/start" motions with your legs (sprints, hurdles, long jump). During vigorous activities we often load our hip joint by up to eight times our body weight.

Individual activities can put a lot of continuous pressure on your hamstrings (running, water skiing, skating, cheerleading, dancing, weight lifting, climbing). These athletes are susceptible to chronic pulls as a result of the repetitive nature of their activities. They often suffer from avulsion fractures following a burst of speed.

Muscle exhaustion and fatigue decrease your strength, power and endurance which increase your risk for injury. Over-stretching, overexertion and overuse of your hamstring muscles occurs frequently in sporting activities and/or daily life. When you have not warmed-up and stretched properly before moving, your muscles aren't ready for the stress, therefore your chances for injury are increased. Doing too much, too soon, too fast, or exercising and moving about in cold weather, puts you at even more risk for a pulled hamstring. Sometimes you will get a pulled hamstring doing very simple tasks like landing in a strange way from a jump, aggressively stretching in yoga class, or running after your kids or the bus.

Utilizing a poor technique (over-striding in running or walking), improper equipment (old shoes) or hard and uneven training surfaces during activities will often put your body at a higher risk for injury. These will also make you feel more tired as the inefficient movements require you to use more energy to complete tasks than required.

Repeated hamstring injuries are very common. They decrease the function and strength of your hamstring over time, and encourage inflammation, scar tissue and calcification development, so these damaged parts never heal properly. Impatience and incomplete rehabilitation (not letting injuries heal, so your body can return to peak performance level) is often the reason for repeat injury. This is seen most frequently in runners. Previous injuries to your lower back, pelvis, knees, calf and/or achilles tendon can also instigate a hamstring injury (especially if they haven't healed properly).

The above causes are often self-imposed; which means with a little self-management you can have some control over the outcomes. However, the following conditions can make you more prone to hamstring injuries and be the cause of a number of the above situations.

Muscle imbalances or weakness in your muscles (especially in your hamstrings and quadriceps, or your lower back and pelvis muscles) can cause strength differences and poor coordination that result in a pulled hamstring. Your quadriceps often overpower your hamstrings (generally if hamstring strength is less than 60% of quad strength), which is seen frequently with triathletes as they mix running and cycling.

Tight hamstring muscles often result from not stretching properly before your activities. However, shortened and tightened muscles, spine stiffness and poor flexibility can be hereditary and/or a side-effect of aging; it is seen more frequently in men than women. All of these can cause a lot of pressure on your body (low back stiffness can pressure your sciatic nerve which causes your muscles to tighten) and require a lot of work on your part (daily stretching).

Alignment issues, leg length discrepancies, or overpronation or supination (which affects the way your foot hits the ground when you walk) can put a lot of stress on your hamstring muscles and result in a pulled hamstring. Overpronation occurs in at least 60% of people with hamstring strains.

Other factors that can put extra tension on your hamstring and influence your risk of experiencing a pulled hamstring include:

• Poor fitness levels and lack of exercise
• Poor nutrition and obesity
• Posture irregularities (lumbar lordosis)
• Meniscal injuries
• Neural tension (scar tissue around the nerves)