Biomechanics Problems

PPT Submission Guidelines Arrows and lines can be found using the “Shapes” function (blue circle) under the “Insert” tab (black circle) shown below. The text box function can be used to write out the solutions to the problems (red circle). The equation and symbols (purple circle) function can also be used to write out the solutions and contain mathematical symbols. Steps to Construct a Free Body Diagram 1. Identify and isolate the free body of interest. 2. Establish a coordinate reference frame (this is provided for you in the assignment). 3. Draw all internal and external forces that act on the system. 4. Draw the joint reaction force. 5. Write and solve the governing equations of motion. Scenario 1: Seated Knee Extension (3 pts) 1. Assume that the system pictured is in static rotary equilibrium. Use the information provided to solve for the quadriceps force. Leg mass = 2.7 kg EMA to leg COM= 0.15 m Quadriceps IMA = 0.01 m Muscle force of quadriceps = ? Scenario 2: Lateral Arm Raise (4 pts) 2. Assume that the system pictured on the next slide is in static rotary equilibrium. What is the internal torque/moment produced to maintain the arm in in this position during the lateral arm raise exercise? 3. How could you modify this exercise to reduce the demand on the deltoid muscle? Please provide 2 different modification ideas to accomplish this goal for the exercise. Scenario 2: Lateral Arm Raise (4 pts) R arm is at 90 degrees from the body Dumbbell mass: 15.9 kg Arm mass= 2.7kg EMA to dumbbell weight = 0.76 m EMA to arm COM = 0.45 m IMA middle deltoid = 0.02 m Muscle force middle deltoid = ? +y +x Senario 3: Hip Handheld Dynamometer Testing (2 pts) 4. What is the external force being recorded by the dynamometer in this hip abduction muscle testing scenario? Dynamometer force = ? EMA to dynamometer = 0.3 m Hip abductor IMA = 0.01 m Muscle force of hip abductors = 3400 N Handheld dynamometer Assignment Reflection(1 pt): 5. What did you think of the magnitude of the forces and torques/moments generated by the body in the simple scenarios shown? Please briefly explain how understanding this information could assist you PT practice? **Please limit your answer to 5 sentences or less