I'm pretty sure its called a compound fracture
<span>How can a person directly influence you to buy a health product?
- that everyone is talking about this product
<span>- its effectiveness</span></span>
The answer is tighten and contract.
In order for the students to pull the rope their muscles will need to tighten and contract so they are able to continuously pull with all their strength and power. Relaxed or twitched muscles will result in release of the rope.