i have seen calculating the resistance arm as the length of the object to the connection of the biceps not to the elbow joint. Is this false?

@DrVeronicaFoster

8 ай бұрын

That would be incorrect, it is measured to the axis, which is the elbow. If you measure from the resistance to the biceps insertion, then you are measuring the difference between the resistance and effort arms, rather than measuring the resistance arm itself

Lost me in the equal and opposite torques….

@DrVeronicaFoster

5 ай бұрын

I'm really glad you commented because I'm happy to explain! Are you familiar with Newton's third law of motion? It says that for every action there is an equal and opposite reaction. In this case, we can replace the word "action" with torque. For every torque that occurs at a joint, there also exists an equal torque that is going in the opposite direction as the first. The two opposing torques that occur simultaneously at a joint are actually working to cause the same joint action. The difference is which segment is moving. For example, let's look at knee flexion. If someone is standing and they are going to flex the knee, there are two ways to do it. Either the tibia comes up to meet the femur or the person does a squatting motion to bring the femur down toward the tibia. The torque that causes the tibia to go up to the femur is opposite of the torque that causes the femur to come down to the tibia. They are opposing torques, but they both generate the same action. Which torque causes the motion depends on the rest of the system and its constraints. Let's look at elbow flexion as another example. If you are doing a bicep curl, then the radius/ulna come up to meet the humerus. That is because the upper extremity in that case has less inertia and isn't restrained compared to the rest of the body, so it is what moves in response to the torque. If you do a pull-up, the upper extremities are anchored to something stationary, which makes them the more stable segment with more inertia. That means that when you flex the elbow, the humerus comes up to meet the radius and ulna, because the body has less inertia than the equipment that you are hanging from. It is the same concept as when we exert force through our feet into the ground (like during gait), and the ground exerts an equal and opposite force back into our feet. The force is equal in both directions, but because your body has less inertia than the ground you're walking on, the force causes you to move across the room, rather than the ground to move out from underneath you. I hope that helps clear things up, and thanks for watching!

@urassisdragon

5 ай бұрын

This helps. Would you have any problems you could post or send me with solutions so I could make sure I got a handle on this? Thank you for making this video. When I was in o and p school they were always talking about moments and I got really confused because what they were saying sounded like torque. Finally figured out they are the same.

@urassisdragon

5 ай бұрын

This helps. Would you have any problems you could post or send me with solutions so I could make sure I got a handle on this? Thank you for making this video. When I was in o and p school they were always talking about moments and I got really confused because what they were saying sounded like torque. Finally figured out they are the same.

@urassisdragon

5 ай бұрын

This helps. Would you have any problems you could post or send me with solutions so I could make sure I got a handle on this? Thank you for making this video. When I was in o and p school they were always talking about moments and I got really confused because what they were saying sounded like torque. Finally figured out they are the same.

@urassisdragon

5 ай бұрын

This helps. Would you have any problems you could post or send me with solutions so I could make sure I got a handle on this? Thank you for making this video. When I was in o and p school they were always talking about moments and I got really confused because what they were saying sounded like torque. Finally figured out they are the same.