It is imperative that you warm up before you work out. A thorough warm-up prepares your body for the upcoming demands of more intense exercise. This means that your warm-up should be active and rhythmic, which makes the muscles more pliable and less susceptible to injury. Many women believe they need to perform a stretching routine before beginning a strength training workout, but this is not true. Static stretching is actually counterproductive because it decreases the muscles ability to create power.

A thorough warm-up raises the core body temperature, increases blood flow to the heart and working muscles, rehearses forthcoming movements, and lubricates the synovial joints. For each degree of increased internal temperature, the metabolic rate of cells increases by about 13 percent (Astrand and Rodahl 2003). The increased temperature of the body decreases the potential for injury because neuromuscular coordination increases, fatigue is delayed, and tissues are less susceptible to injury or trauma. 

The American Council on Exercise (2007) listed the following additional physiological benefits of a warm-up:

• Increased metabolic rate. When the body temperature begins to increase in preparation for exercise, the metabolic rate increases and the endocrine system begins to unload hormones that help the body prepare for exercise and activity(cortisol, insulin, and adrenaline). This increases the rate at which energy production occurs.

• Higher rate of oxygen exchange between blood and muscles. As part of the warm-up process, the lungs take oxygen from the red blood cells faster, which increases the rate of exchange between the muscles and the blood. Also, waste products such as carbon dioxide and other toxins are exchanged for oxygen at a faster rate.

• Increased muscle elasticity and flexibility. 

The soft tissues of the body (muscles, tendons, and ligaments) become more pliable and are more easily moved into a variety of positions when the body temperature increases because of the increased blood flow to those tissues. Muscles, tendons, and ligaments that are more responsive to sudden changes in position are much less likely to become injured during exercise.A thorough warm-up has two parts: the general warm-up and the dynamic warm-up. The general warm-up focuses on increasing joint lubrication, heart rate,and core body temperature. Activities that are appropriate here generally prepare the body for the upcoming exercise session and increased physical movement.

The dynamic warm-up is more specific to the activity you are performing the warm-up for. For example, if you were about to start a 3-mile (4.8 km) run, you might begin by jogging slowly to specifically warm up for the activity of running.If you were strength training, the dynamic warm-up might include ROM activities. For example, if you are going to perform squats, you should go through some squats without any additional load (weights), focusing on the ROM that you want to go through while squatting. (Later, we outline some dynamic stretches that are appropriate for most strength training workouts.)

A general warm-up should increase your core body temperature to the point of sweating. Breaking a sweat is a good measure of the quality of your general warm up.You can use the treadmill, elliptical trainer, recumbent cycle, or stair climber,or just take a walk or jog around the track to break a sweat. This should take three to five minutes or longer depending on the physical environment, current injuries,or your medical conditions.Once you have broken a sweat, you are ready to engage in the second part of the warm-up, which includes dynamic flexibility and core engagement. 

These activities should continue to increase your core body temperature and further prepare you physically and mentally for the upcoming workout. Dynamic flexibility should engage your core, increase the length of your muscles, and increase your joint ROM. Remember, these are dynamic moves, so once you get into position, move with control in and out of each posture in flowing sequences for the prescribed  number of repetitions. I recommend that you perform three to five of the following dynamic flexibility exercises to prepare for a workout.