Hamstring injuries are among the most common muscle strains experienced by athletes.1 Of the hamstring group of muscles, the biceps femoris is the muscle most often involved.2 Hamstring injuries can be caused by several factors, all of which respond well to chiropractic care.
Hamstring muscle imbalances often contribute to, or may be caused by, pelvic malpositions and spinal subluxations.3 Chiropractic care for hamstring injuries should include a postural evaluation of the lower extremities, since custom-made orthotic support may be required, especially for rear-foot function.
What Are Hamstrings For?
The main functions of the hamstrings are to control knee extension by the quadriceps, extend the hip joint and flex the extended knee joint. Proper hamstring function is very important for gait efficiency and stability of the knee joint. When the quadriceps muscles extend the knee joint, the hamstrings act as a brake to slow forward movement of the tibia. Hamstrings can be overwhelmed by quadriceps that are too powerful, resulting in a sudden muscle tear during a strenuous activity, such as sprinting.4
Joint Control
During running, the hamstrings are most active during the last 25 percent of the swing phase and the first 50 percent of the stance phase.5 This first half of stance phase consists of heel strike and maximum pronation. The leg muscles, including the hamstrings, function to control the knee and ankle at heel strike and help to absorb some of the impact. A 1999 study showed a significant decrease in electromyographic activity in the hamstrings when wearing orthotics.6 In fact, the biceps femoris had the greatest decrease in activity of all muscles tested, which included the tibialis anterior, the medial gastrocnemius, and the medial and lateral vastus muscles. Previous studies had already demonstrated a significant decrease in tibial internal rotation7 and pronation velocity8 when using orthotics. The researchers theorized that the additional support from the orthotics helped the hamstrings to control the position of the knee and absorb some of the shock of heel strike.
Care and Prevention
When an athlete presents with a hamstring injury, acute care and return to sports activities at the appropriate time receive top priority. The final stage, though, must consider the need for custom-made, flexible orthotics in order to reduce hamstring stress and prevent re-injury.
Acute care: Hamstring injuries are best treated with the PRICE formula: Protection for the injured muscle (an elastic wrap helps prevent further injury); Rest from strenuous activities; Icing to reduce inflammation, swelling and pain; Compression to decrease bleeding and congestion; and Elevation to encourage drainage and prevent lymphatic stasis. Passive stretching and lengthening should be started as soon as tolerable to prevent the muscle injury from healing in a shortened position.
Check for misalignments and imbalance: Hamstring strains are commonly associated with spinal/pelvic misalignments and dysfunctions. Because there is often no way to tell whether muscular strain affected the pelvis and spine, or vice versa, both areas must be treated for a complete response. Pre-existing muscle imbalances also may contribute to hamstring strains. The gluteus maximus muscle is often relatively weak, causing the hamstring to work harder to extend the hip joint. This may be found along with an iliopsoas muscle that is shortened or hypertonic on the same side. The tightness of the iliopsoas inhibits the gluteus maximus, thereby placing the hamstring at a disadvantage.9
Foundational Support
A custom-made, flexible foot orthotic that helps to position the rear foot at heel strike, absorb some (or most) of the impact, and reduce overpronation can speed healing from a hamstring injury and reduce the possibility of recurrence. Therefore, an important component must be a varus wedge (or pronation correction) under the calcaneus. The use of shock-absorbing viscoelastic materials under the heel is needed to decrease the shock-wave transmission up the leg. And finally, sufficient support for the arches of the foot (especially the medial longitudinal arch) must be included to prevent prolonged pronation in the first half of the stance phase. An orthotic that incorporates all of these factors should be provided to athletes who want to return to full participation in their sport.
Getting Patients Back on Track
We now have several reasons to include orthotics in the treatment protocol for hamstring strains. Electromyography investigations have shown that the use of orthotics has a direct effect on the hamstring muscles. By significantly reducing the strain of running, a well-designed, custom-made orthotic can help to speed a full return to sports and prevent re-injury.
References
- Askling CM, Tengvar M, Saartok T, Thorstensson A. Acute first-time hamstring strains during high-speed running: a longitudinal study including clinical and magnetic resonance imaging findings. Am J Sports Med, 2007;35(2):197-206.
- Slavotinek JP, Verrall GM, Fon GT. Hamstring injury in athletes: using MR imaging measurements to compare extent of muscle injury with amount of time lost from competition. Am J Roentgenol, 2002;179(6):1621-28.
- Muckle DS. Associated factors in recurrent groin and hamstring injuries. Br J Sports Med, 1982;16:37-9.
- Roy S, Irvin R. Sports Medicine: Prevention, Evaluation, Management, and Rehabilitation. Englewood Cliffs, NJ: Prentice-Hall, 1983:298.
- Mack RP. AAOS Symposium on the Foot and Leg in Running Sports. St. Louis: Mosby; 1982.
- Nawoczenski DA, Ludewig PM. Electromyographic effects of foot orthotics on selected lower extremity muscles during running. Arch Phys Med Rehabil, 1999;80:540-4.
- Nawoczenski DA, Cook TM, Saltzman CL. The effect of foot orthotics on three-dimensional kinematics of the leg and rearfoot during running. J Orthop Sports Phys Ther, 1995;21:317-27.
- Eng JJ, Pierrynowski MR. The effect of soft orthotics on three-dimensional lower limb kinematics during walking and running. Phys Ther, 1994;74:836-44.
- Geraci MC. Rehabilitation of the Hip, Pelvis, and Thigh. In: Kibler WB, ed. Functional Rehabilitation of Sports and Musculoskeletal Injuries. Gaithersburg, MD: Aspen Pubs, 1998, p. 225.
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