.......................

.......................

.......................

.......................

Training / Training Talk

Running Training Talk...............................

A Pain in the Butt…
By Susan S. Paul, MS
TSF Training Program Director

As a Coach and a Massage Therapist, I have seen and treated many hamstring injuries- including my own. Hamstring strains are a common and all too recurrent running injury that is, quite literally, a pain in the butt. A muscle strain is an injury that occurs when the local mechanical limits of the muscle tissue are exceeded. Strain injuries typically involve muscle fiber damage usually at the site of the muscle and tendon junction. Hamstring strains most often occur at their proximal attachment site located at the base of buttock and the top of the leg. Runners are generally required to take a few weeks to a few months off from training. Research indicates that 1 out of 3 runners with hamstring strains will have a re-injury within one year of returning to training. However, a recent study by researchers from the University of Wisconsin, published in the American College of Sports Medicine’s Exercise and Sport Sciences Reviews July 2006, offers great insight, hope, and implications for new rehabilitation techniques. Read on if you wish to prevent the dreaded “Pain in the Butt” Syndrome.

THE STUDY
Researchers from the University of Wisconsin used neuromusculoskeletal models to track the activity of the hamstrings during the entire cycle of the running gait. By utilizing these models, they were able to pinpoint the exact site where hamstring injuries most often occur, when during the running gait cycle injuries most often occur, and why the hamstrings are so susceptible to strains during running.

Magnetic Resonance Imaging (MRI) analysis of 170 injured athletes revealed that approximately 80% of hamstring strains involved the biceps femoris; specifically the long head of biceps femoris. The biceps femoris muscle splits into two heads or muscle bellies. The short head attaches to the rear aspect of the femur. The long head attaches to the ischial tuberosity, a bony landmark on the posterior aspect of the pelvis that is sometimes referred to as the “sit bones”. It was found that hamstring strains occurred most often at this proximal attachment site, at or near the ischial tuberosity.

Using the neuromusculoskeletal models, researchers identified that the moment in the running gait cycle that the strain injury most often occurs is during the forward hip and leg swing, just before the foot hits the ground. At this point in the gait cycle, the hamstrings were found to be elongated and undergoing an eccentric contraction. An eccentric muscle contraction is an active lengthening contraction; whereby the muscle actually lengthens and fires its’ contractile units at the same time. This is somewhat analogous to taking a rubber band, stretching it out to its’ maximum length, and then trying to wrap it around an object. Most likely the rubber band will break as you try to wrap it around something…so it should be no surprise to you that your hamstrings object when placed under similar circumstances.

The magnitude of peak elongation or eccentric contraction was significantly greater for the biceps femoris long head than for the other hamstring muscles; therefore, making it the most susceptible to injury. During hip flexion and knee extension, the biceps femoris was found to be elongated 9.5% beyond its’ normal upright posture length; while the other two hamstring muscles, semimembranosus and semitendonosus, were 7.5% and 8.1% respectively. Researchers concluded that the biceps femoris sustains injury during the lengthening eccentric contraction in the late swing phase of the running gait cycle due to the amount of mechanical load placed on the muscles tissue.

The researchers also concluded that the hip flexor muscles have as large an influence on hamstring elongation as the hamstrings themselves. The hip flexors were found to directly affect pelvic tilt, or the angle of the pelvis. Tight hip flexors and strong quadriceps, typically found in runners, lead to a greater than normal anterior pelvic tilt. Anterior pelvic tilt necessitates greater hamstring elongation because as the pelvis is pulled forward and down by strong hip flexors and quads in the front, the posterior aspect of the pelvis becomes elevated creating even greater elongation on the hamstrings- specifically biceps femoris; therefore, making them even more susceptible to injury. The neuromusculoskeletal models showed that other proximal muscles acting on the pelvis; such as rectus abdominus, internal and external obliques, and the erector spinae, also substantially influence hamstring elongation through their affect on the pelvis. This means that neuromuscular control of trunk and pelvis muscles can affect hamstring strain injury risk.

REHABILITATION
Hamstring strains have a very high rate of recurrence with approximately one out of three athletes reporting re-injury within a year of returning to running. This high re-injury rate implies that there may be an inappropriate criteria set for determining when runners should return to running; as well as, that traditional rehabilitation methods may be insufficient for reducing the risk of re-injury.

Traditional rehabilitation emphasizes specific hamstring stretching and strengthening exercises. The Wisconsin study found that when rehabilitation focused on early movement and neuromuscular control of all the trunk and pelvic muscles, including the hamstring muscles, it dramatically reduced hamstring re-injury rates. Rehabilitation that included agility training and trunk stabilization exercises in addition to specific hamstring strengthening and stretching exercises yielded the best results. None of the 13 athletes in the agility and trunk stabilization program reported re-injury even after 1 year of returning to running activities; whereas, 6 of the 11 athletes (54.5%) participating in traditional rehabilitation of isolated hamstring stretching and strengthening exercises reported re-injury within 1 year.

The Wisconsin researchers suggest that more research is necessary to determine exactly why the agility and trunk stabilization program provided such results, but one hypothesis is that improved neuromuscular control of the lumbo-pelvic region minimizes anterior pelvic tilt and allows the hamstrings to function at safer lengths and loads during athletic movement, thereby reducing injury risk. Another hypothesis is that early intervention and treatment also limits the residual adverse effects of scar tissue formed early in the remodeling process.

Both hypotheses and the results of this hamstring strain study provide GREAT reasons to be seen, diagnosed, and given a Physical Therapy prescription, and start strengthening your trunk and pelvic muscles as soon as possible if you sustain a hamstring injury! Suggestions to lower your risk factors of hamstring strain:

WHAT NOT TO DO:

Runners often feel pressure or pain at the bottom of their buttock or the top of their leg. This feeling leads us to think that our hamstrings are “tight” and that we need to stretch them. We bend over to touch our toes thinking that we need to “stretch” out our hamstrings because they are contracted. This is the WORST thing we could possibly do! If you are feeling pressure, pain, or “tightness” at the proximal hamstring attachment, you need to stretch your quadriceps NOT your hamstrings! By stretching the quadriceps and hip flexors you minimize the anterior tilt of the pelvis and reduce the stress on elongated hamstrings.

WHAT TO DO:

All runners risk hamstring strain. Part of the reason lies in the natural imbalance between our hamstrings and our quadriceps. The quadriceps are a stronger muscle group than the hamstrings, and activities like running and spinning emphasize our quadriceps making them even stronger, this leads to anterior pelvic rotation and; therefore, place our hamstrings at greater risk for injury. Strengthening your trunk and pelvic muscles will minimize the anterior rotation of your pelvis; thereby reducing your risk of hamstring strain.

Stretch these muscles:
Quadriceps	Stabilize yourself and bring one foot up behind you to your buttock. Hold this foot in your hand and pull gently, keeping your knees together, tuck your pelvis under you and tighten your abdominal muscles.
Hip flexors	Kneel on one knee. Gently press forward until you feel a stretch in your quadriceps and groin area.
Low back muscles	Lie on your back and bring your knees into your chest. Tighten your abdominal muscles and make sure that your low back is touching the floor.

Strengthen these muscles:
Hamstrings	Hamstring curls; use a relatively light weight and focus on completing the full range of motion
Rectus abdominus	Abdominal curls and crunches (sit-ups with bent knees) and reverse abdominal curls
Obliques	Sit-ups that cross the body; bring the opposite elbow to the opposite knee Adductors- Use the adductor machine and a light weight. Focus on working the inner thigh muscles and completing a full range of motion

Run every other day:
If hamstring strain is a concern for you, running every other day allows your hamstrings the necessary time to recover. This would also provide you the time to add cross-training into your fitness plan.

Cross-train:
Add specific cross-training exercises to your routine that strengthen the lumbo-pelvic muscles. By strengthening these trunk and pelvic muscles you will help support and stabilize your pelvis; therefore, you also support your hamstrings. Try Pilates, Yoga, Plyometric exercises, Boot Camp classes, or Agility exercises.

Spinning:
A popular cross-training exercise for many runners and is a good alternative to running.

Massage therapy:
Athletes that are receiving massage therapy can ask their therapist to pay particular attention to their quadriceps, hip flexors, and lower back muscles.

CONCLUSION
This study gives runners hope for returning to running after a hamstring strain and even greater hope for preventing hamstring strain altogether! Make a specific plan of action for your cross-training and/or rehabilitation just as you would make a training plan for running a marathon or a triathlon. Incorporate Pilates, Boot Camp Class or weight training into your plan. Strengthening your trunk and pelvic muscles will reduce your risk of hamstring strain AND help make you a stronger and faster runner!

about us | retail store | events | foundation | training | sponsors | contact us