Lower back pain due to irritation of the lower lumbosacral nerve roots causes pain and spasm in muscles of the lower back and the lower limbs. There will be loss of balance with tendency to fall when muscles do not contract quickly in a coordinated fashion due to pain, spasm or weakness. The muscle important for walking is the gluteus maximus at heel strike which has to undergo a lengthening contraction to stabilize the hip joint. The quadriceps muscles and muscles that pick up the foot and ankle (dorsiflexors) also undergo lengthening contractions as the body weight is gradually transferred over the supporting limb.
When the body weight is totally transferred over to the supporting limb, the gluteus medius of the supporting limb is important to prevent the non-supported hip and pelvis from dropping. The soleus muscle is active during mid stance to prevent the knee from buckling. During the push-off phase, the gastrocnemius and soleus muscles are important for lifting the heel off the ground.
To lift the lower limb and swing it forward, the hip adductors and hip flexors are very important. In the mid and late stance as well as the swing phase of walking, the muscles undergo shortening contractions and are not as vulnerable to injury. A person is most prone to injury during the early phase of stance since most of the muscles have to undergo lengthening contractions. When this is compounded by presence of pain spasm or weakness the person will have a tendency to fall.
Therefore shortening contractions are important for strengthening the gluteus maximus, gluteus medius, quadriceps and foot and ankle dorsiflexors.
