Sports physicians and physical therapists know that hamstring injuries can be troublesome. If you are treating athletes who depend on running agility and speed and yet repeatedly present weak hamstrings, test their hamstring strength. Even in the non-athlete, recurring hamstring fatigue and pain signals the need for professional assessment. Two major concerns accompany hamstring problems: muscle weakness with pain; and neural weakness, which is not always accompanied by muscle pain. Tests help secure the correct diagnosis.
Test with functional knee bridging. Have the patient lie back on a table, place their affected leg's heel on your shoulder, and position the hip angle at 30 to 45 degrees. Instruct the patient to push downwards on your shoulder and, with only that leg, attempt to lift their hips off the table. Observe the working hamstring's contraction, note any weakness and inquire about any pain. Repeat this test with the patient's knee flexed 45 degrees, and a third time with 90-degree flexion.
Test with resisted knee flexion. Again position your patient on their back, and extend their affected leg along the table. Have him contract his hamstrings to pull their heel towards their butt, while you resist by holding the patient's ankle in place. Weakness and pain during these hamstring contractions signal probable muscle injury; weakness alone signifies probably nerve dysfunction.
Conduct the slump test. Have the patient slump forward toward the knee of the affected leg. You may carefully assist by helping her pull downwards, but do so with caution and ask the patient how they feel. If, during the stretch, the patient experiences a shooting pain down the back of the leg, the hamstring weakness may be neural rather than muscular.
Palpate the affected muscle. Testing for muscle weakness may require you to manually knead the muscle and feel it for tightness, swelling or tissue irregularities. Physically palpating the hamstrings will help you find weak, loose areas. You might also find places of tension that contribute to adjacent, or referred, weakness.
Test with a straight leg raise. The Sports Injury Clinic dynamically illustrates a straight-leg stretch with the therapist lifting the patient's extended leg. This maneuver can help determine the extent of the hamstring's weakness or injury. If your patient has strong, flexible hamstrings, there will be no pain when you raise their heel upwards. A weak hamstring will not tolerate being raised more than a few inches; the normal range of movement should be 80 to 90 degrees.