from the American Council on Exercise
ACE asks "Suppose you were told that you only had to add an extra five to 10 minutes to each of your workouts in order to prevent injury and lessen fatigue. Would you do it?" Those few extra minutes are called a warm-up.
A gradual warm-up:- Leads to efficient calorie burning by increasing your core body temperature - Produces faster, more forceful muscle contractions - Increases your metabolic rate so oxygen is delivered to the working muscles more quickly - Prevents injuries by improving the elasticity of your muscles - Gives you better muscle control by speeding up your neural message pathways to the muscles - Allows you to work out comfortably longer because all your energy systems are able to adjust to exercise, preventing the buildup of lactic acid in the blood - Improves joint range of motion - Psychologically prepares you for higher intensities by increasing your arousal and focus on exercise
Your warm-up should consist of two phases: 1) progressive aerobic activity that utilizes the muscles you will be using during your workout, and 2) flexibility exercises. Stretching muscles after warming them up with low-intensity aerobic activity will produce a better stretch since the rise in muscle temperature and circulation increases muscle elasticity, making them more pliable.
For more information click here to read the whole story from the American Council on Exercise.