The first thing we need to prepare is the ability of our nervous system to produce intense contractions of the musculature we are intending to train.
You need to stimulate the muscle tissue through tension to start getting the neurons firing faster and neurotransmitters flowing. The nervous system is not ready to fire at 100% at a moments notice. It needs a stimulus to start increasing its firing rate to be able to produce more intense contractions. We refer to this as potentiation.
It’s like jumping in your car after it’s been parked all night. The engine is cold and not ready for you drag race (which is basically what you’re doing in a high intensity workout as far as your nervous system is concerned). You need to turn the car on, let it idle for a bit and then start revving the engine to get it warmed up before you’re ready to floor it.
One simple and safe way to potentiate your nervous system to contract the muscles you’re about to train is to perform an isometronic in a stable exercise. This entails choosing a weight that you cannot fully complete the rep so that you get “stuck” near the end of the movement and contracting as hard as you can for 4-6 seconds.
Learn more about the difference between isometrics & isometronics in THIS ARTICLE.
Another way is simply to perform practice reps of the exercise you’re about to perform and gradually increase the load. You may even “warm up” to a load above your working set weight but with much lower reps. For example, you’ll be training with sets of 8-10 but only doing 3-4 reps on each warm up set and maybe only 1 rep of a load heavier than your working weight.
You don’t have to do this for every exercise. Usually just the first exercise for a particular muscle will do. More practice sets are usually required for more complex lifts like squats and deadlifts while you might only need 1-2 for simpler ones like curls or extensions. Keep in mind, the lower your working rep range will be the more practice sets you may need.
It is also perfectly acceptable to perform both methods. Start with an isometronic (1 rep) and then begin your practice sets. You just might be able to start with a bit heavier load for your first practice set.
This second method also leads into the next point in preparing for intense exercise.