The missing link to your warm ups, prime your Central nervous system ready for work.
What does the Central nervous system (CNS) have to do with working out?
The CNS is made up of your brain and spinal cord. The central nervous system sends messages to muscles to prepare them for movement. Prior to moving your body, the brain responds first telling your body how to perform said movement and how much force/muscle fibres should be recruited. Activing the CNS will help recruit more high threshold motor units (stimulates a greater amount of muscle fibres), which will allow you to lift more powerfully from the increase muscle force and rate of force development.
See how this can effect your workout in a positive way?
How to activate your CNS prior to lifting
To simulate the central nervous system, one must perform high velocity/powerful exercises for a short duration prior to your heavy lifts. The main objective is to do the exercises with 'intent'...the 'intent' to go as powerful and fast as possible. Perform 2-3 sets of no more then 5 reps of an explosive exercise after your mobility/stability warm up, to get yourself firing. Now... one key point to point out, CNS activation exercises should be specific to your first lift, If you're performing squats, you would want to do lower body CNS activation exercises such as Box jumps. Something similar/mimincs the same movement pattern.
Try some of these examples
2-3 sets, 3-5 reps
Box squats - prior to Back squats
Kettlebell swings - prior to Deadlifts
Medicine ball throws - prior to Bench press
Banded explosive straight arm pull downs - prior to pull ups
Again, these want to be done as fast and explosive as possible, you're not trying to pull a heavier weight. You should feel enlightened afterwards, not fatigued.