warm up provides an increase in muscle

Many coaches and physiologists believe that a longer warm up provides an increase in muscle temperature, acceleration of oxygen uptake kinetics, increased anaerobic metabolism and a process called postactivation potentiation of the muscles. However, very few studies have studied if warm ups has a detrimental effect on performance.
As it turns out, the warm-up is one of the more contentious issues in high-performance sport. Different coaches have different theories and not a lot of quality research has been done to identify the optimal warm-up. Tomaras' study suggests that at the very least, athletes may want to lower the intensity and reduce the amount of time that they warm up.