Figure 1.16 The base of support in various positions. (A) Supine. (B) Sitting. (C) Standing, narrow base of support. (D) Standing, wide base of support.
Clinical Connection 1.4
During movement, a person’s ability to balance on the base of support can be related to function and safety. People who have decreased balance and are at a higher risk for falls often walk with a wider base of support to attempt to increase their stability. Their base of support may be outside the trunk, as the feet are placed wider than the alignment with the trunk. People who have good dynamic standing balance may be able to reduce their base of support and stand on just one leg and perform a single leg jump.
person lying in a supine position on a surface has a lower center of gravity and a larger base of support compared with a person standing on only one leg.
STRESS–STRAIN RELATIONSHIP
The magnitude and duration of an external force and the ability of the tissue to resist the force determine the infl u- ence or fi nal outcome of the force on the tissue. Whether or not the hamstring muscles undergo a mild stretch or sustain an injury with microtears during a hamstring stretch depends on the intensity and duration of the stretch and the ability of the muscle and connective tissue to counter that stretch. In all musculoskeletal tissues, there is a relationship of their internal resistance with changes produced from the external forces. Although this
