Limp
A limp is a type of asymmetric abnormality of the gait. Limping may be caused by unequal leg lengths (short leg limp), experiencing pain when walking (antalgic limp, or trendelenburg gait), muscle weakness, disorders of proprioception, or stiffness of joints (in arthritis, for example).
Someone taking a step with a limp appears to begin to kneel and then quickly rise up on the other leg; to bystanders the process may appear arduous and painful, but this is not always the case.