Should you warm-up? The short answer is yes. Warming up isn’t a waste of time; being injured is a waste of time. A correctly designed warm-up prepares the body for the stress you are about to subject upon it. It primes joints and body tissue for the activity they are about to undertake, therefore reducing the chance of injury and improving performance. A cleverly designed warm-up will also improve mobility helping you to achieve proper technique and posture.
There is more to a warm-up than just getting the blood flowing and the body temperature rising. A warm-up generally shouldn’t include static stretching as this has been proven to be counterproductive. A warm-up should involve low to moderate intensity aerobic exercise and dynamic stretching of all the major muscle groups about to be used.
Another technique that you may want to include in your warm-up is to ramp up. Ramping up primes the body parts that are about to workout by doing the same or similar exercises that you are about to do in your workout. It begins with no or a lower resistance/load and builds up the resistance/load with each set.
After some time strength training, you’ll probably begin to notice that your first set isn’t your best set. It is more noticeable in the big lifts such as back squats, deadlifts, and particularly single leg exercises. Your body seems to click into gear at about the third set. For this reason, the ramp up warm-up makes sense for the first couple of sets, then hitting your full load for your third set.