Why does range of motion need to be measured separately for each joint? a. the average ranges of motion of joints are not known. b. each joint has a different range of motion. c. range of motion can change rapidly in a joint. d. none of the above

One must measure the range of motion of each joint separately. Since flexibility and therefore range of motion is determined by muscle length at a joint, one would come to the conclusion that since each joint has a different set of muscles such the difference between the shoulder and the knee (a joint which rotates compared to a joint that pivots) you would expect to find very different rang of motions.