Warm up
The goal of a warm-up is to gradually increase your heart rate and increase blood flow, thereby warming muscles and connective tissue. A good warm-up also releases synovial fluid which lubricates the joints. During your warm-up it is important to focus on the joints you will be using in your workout. For example, if you want to exercise your chest and back but do a warm up on a stationary bike, you won’t lubricate the shoulder and elbow joints with synovial fluid. This could increase your chance of injury.
A typical warm-up should last about 5-10 minutes. This is a great time to mentally prepare for the workout. Elliptical trainers are great for warming-up because they involve all the major muscle groups. A rowing machine is also a good option. If you like to use the treadmill to warm up, make sure that you also do some arm movement to warm the upper body if you plan to do upper-body strength training. I recommend doing your warm-up before strength training and saving the stretching for the end of your workout, after your cool-down.