Seriously though, warm-ups are one of those easy, but do I really know what I'm doing type issues. What is effective vs. not effective? Do I warm-up like a sport team would? Do I only focus on the body part I am working or do I warm-up my full-body? So many questions.
This linear way of approaching warm-ups was brought to my attention by Charles Poliquin. The reason I enjoy this way so much is that it cuts through the bullshit and gets right to the good stuff. His views on cardio equipment, for instance, is less than flattering but he makes logical arguments on how to get around common pseudoisms.
Even 1 degree is equivalent to a 12% increase in strength. Cardio equipment is not the answer. Cardio has an adverse effect and gets be detrimental. Resistance is needed. Sprints, dynamic movements, etc.
Prevent 30% of injuries with a proper warm-up. Adversely, stretching (statically) increases the injury rate by almost 50% as it does a poor job of priming the CNS and actually relaxes the muscles. If you don’t have time to warm up, you don’t have time to train.
This is usually done after doing the first warm-up set when you can assess what needs to be taken care of. Use systems such as PNF or KCE (contract and relax, hold-relax, hold-relax w/ antagonist contraction.)
Two things a warm-up should accomplish: The degree of motion to which you will be moving and what weight you will be loading. Warm-up guidelines:
Go above the weight you want to perform that day for a single rep set, priming the muscle to take on more weight and making the first sets seem lighter. So let’s say, you want to do 5 sets of 5 reps at 100 kg, the process would look like this:
Additional Notes: activation warm-up exercises did not provide any performance benefit. Researchers write that “coaches should use the limited time available for warm-up to work efficiently,” and to “pass” on functional exercises.
Squatting warm-up: Prep the calves as they are responsible for most knee injuries when not mobile.
Bench: Prep the rotator cuffs for shoulder health. Make sure you’re doing trap 3 raises, external rotations or other movements as such.
In the end, you want replicate what you'll be performing that day and making sure that additional muscles such as rotator cuffs, calves, forearms, erectors, and your "core" are all primed to lift some weight. Avoid activities that relax the CNS or muscles, promoting less tension and more possibility for injury/poor performance.