the same way the training program is going to be different from time to time because of variables like strength, flexibility, injuries, change of goals, balance and symmetry and etc, your warm-up should be based on some factors as well but unfortunately, the majority of us just stick to a warm-up routine and do it for years regardless of what our training session consists of and what areas actually need improvement.
warm-up is not just about pumping blood to your muscle and covers a wide range of topics by itself. every individual needs a specific warm-up program but for the majority of the population, it must consist of flexibility, joint lubrication, building mind-muscle connection by performing the exercises without resistance, checking for pain and discomfort, meditating and getting to the right mental state, checking for imbalances and asymmetrical factors like size or lack of range of motion on one side, core stability engagement training, warming up the lungs and pulmonary system, raising pulse and pumping blood to the muscle as mentioned.
today we are going to talk about flexibility. a lot of people think of flexibility as the ability of the muscle to get stretched massively and that is wrong! every muscle has an antagonist(or antagonists) muscle that does the opposite of itself(either one muscle or a group of muscles together).
when you stretch a muscle too much, you are making the opposite tight and vise versa so flexibility means a balance between these two to be able to have the best range of motion and balanced look.