The lengthening and contraction protocol assessment measures the capability of a muscle to resist injury by measuring the contractile force before, during and after extending the muscle beyond its optimal length. The muscle is contracted while being extended 10-20% beyond the optimal length. Measurements may be carried out on the extensor digitorum longus (EDL), soleus or diaphragm muscles. There are two possible endpoint measurements for this technique; the eccentric force lost which is the drop in force as the muscle is lengthened or, the isometric force lost which is comparing the force generated at optimal length before and after the lengthening contractions.