90 should abduction 45 shoulder abduction 1.) Label the figures above. Include axis of rotation, center of masses, moment arms and forces. 2.) What force is generating the abduction force (i.e. where's it coming from)? 3.) Which forces above are generating the adduction forces? 4.) With the exception of the deltoids, the moment arms for the other torques in this lab are derived by the perpendicular distance from the point of force application (i.e. where the force is acting) to the joint center. Remember that moment arm is always perpendicular to the line/direction of force. Knowing this, do the moment arms in the 45 condition follow the arm (i.e. parallel with the arm) or are they horizontal? 5.) Abduction and adduction are in opposite directions, so choose a sign (+ or -) for each: Abd: , Add: 6.) Since the arm is static in each case, what is the sum (i.e. net) of all torques acting on the shoulder? Nm 7.) Write an equation where all of the above torques sum to the torque value you just provided in question #6 (denote individual torques by the following: example, Im - for the torque from the muscle, etc.)