How does classifying joints according to their structure and function describe human movement

It helps because say the hinge joint had a structure as one of a ball-and-socket joint the knee (where the hinge joint is located) wouldn't bend it would rotate/ spin like our shoulders. This is how classifying joints according to their structure and function can/ may help describe human movement. 

The answer to this will be from your lab notes/procedure. it would be best to ask another student who participated in the lab as we do not know what was done, what enzyme or if the temperature is celsius or fahrenheit. if i were to guess though i'd say the rate stopped due to enzyme denturing at high temperature