The See-Saw Affect of Muscle Imbalances


Patients frequently complain of tight hamstrings. They “stretch them all the time” without any change. During the evaluation, they tend to present with normal soft tissue lengths of the hamstrings during the straight leg raise test. Yet, therapists will often give them hamstring stretches to work on as part of the home exercise program.

The therapist must use sound clinical decision making in this case. By simply prescribing hamstring stretches treats the symptom but does not address the underlying dysfunction. The patient must be educated on why the hamstrings feel tight.

Patients complaining of hamstring tightness often present with anterior pelvic tilts. Their daily activities have created a muscular imbalance between the rectus femoris and the hamstrings group. This may occur due to prolonged sitting as with a desk job or it may be a response to training, especially in runners.

Most of the joints in the body can be viewed as a see-saw. The joint itself is represented as the fulcrum or axis of the see-saw. The seats are representative of the muscles. When a child is placed on each end, the see-saw should remain relatively balanced. However, if a smaller child is put on one end against a larger child on the other side, a great imbalance occurs.

The bigger child represents the short, hypertonic muscle, in this case, the rectus femoris. As the RF pulls inferiorly on the ilium at the AIIS, it can lead to anterior rotation of the ilia on the sacrum that produces subsequent sacroiliac joint dysfunction. As the AIIS moves inferiorly, the other side of the see-saw, the ischial tuberosities, moves superiorly. This increases the tension on the hamstrings that attach there. As tension increases, the hamstrings feel tight from being overstretched.

For the patients who are given hamstring stretches, they will experience short-term symptomatic relief from relaxation of the hamstrings. However, during this time, the rectus femoris can exert a great pull inferiorly due to the lack of resistance from the relaxed hamstrings. Over time, the pelvis will continue to rotate anteriorly and inferiorly and the hamstrings will continue to be overstretched. The chronic ovestretching can lead to tendonitis, tendonosis or strains (tearing) of the hamstrings.

A more appropriate approach is to address the short, hypertonic structures: the rectus femoris. Initial treatment should consist of soft tissue techniques such as instrument assisted soft tissue mobilization with [THE EDGE} can be utilized to quickly address any myofascial adhesions that are creating the shortening. The patient should be instructed on passive, non-weight-bearing stretches keep the length to the rectus femoris. Kinesiology taping with {ROCKTAPE] could also be utilized to change the tone of the rectus femoris as well.

As the patient responds to treatment via improved soft tissue lengths of the rectus femoris, they may also require muscle energy technique to restore normal SI alignment. They would then be progressed to hamstring strengthening exercises to maintain neutral pelvic alignment. Rocktape may still be utilized for neuromuscular re-education to recondition the nervous system to hold the neutral pelvic alignment.

For patients who present with a posterior pelvic tilt, their hamstrings are actually short and hypertonic. However, they tend to complain of tightness in the front of their thighs for the same reason. Initial treatment should focus on restoring normal hamstring lengths and progress to strengthening the rectus femoris as it is the only quadriceps muscle that attaches to the pelvis.