There is a phenomenon called PostActivation Potentiation (PAP). It is the ability to get the most powerful potential from a muscle after it has been “turned on” or activated.
An athlete with relative strength can perform specifically paired exercises in order to create PAP. The athlete will first activate a muscle, tell it to be used (ie. glutes are told to work in a squat pattern), which increases the connection between the brain and the muscle. This message to the muscle increases motor neuron activity and creates change in contractile proteins.
Basically the mind and the body are creating a connection in a specific area.
In theory, once this message has been initiated the muscle is ready to fire explosively. We pair exercises together to initiate the first message, turn the muscle on, and secondly ask the muscle to become explosive!
Research shows that fatigue will play a role in how explosive the muscle can perform following activation. Some rest time is recommended in order to achieve best results.
In the example here I turn the muscles on with some body weight squats and then I demand the body to respond explosively by adding a jump.
You can learn more of the science behind PAP and who it will benefit the most by checking out: The NSCA’s Hot Topic: PostActivation Potentiation