The Warm Up

A proper warm up can increase the blood flow to the working muscle which results in decreased muscle stiffness, less risk of injury and improved performance. Additional benefits of warming up include physiological and psychological preparation.

Benefits of a Proper Warm Up:

• Increased Muscle Temperature - The temperature increases within muscles that are used during a warm-up routine. A warmed muscle both contracts more forcefully and relaxes more quickly. In this way both speed and strength can be enhanced. Also, the probability of overstretching a muscle and causing injury is far less.
• Increased Body Temperature - This improves muscle elasticity, also reducing the risk of strains and pulls.

• Blood Vessels Dilate - This reduces the resistance to blood flow and lower stress on the heart.
• Improve Efficient Cooling - By activating the heat-dissipation mechanisms in the body (efficient sweating) an athlete can cool efficiently and help prevent overheating early in the event or race.

• Increased Blood Temperature - The temperature of blood increases as it travels through the muscles, and as blood temperature rises, the amount of oxygen it can hold becomes reduced. This means a slightly greater volume of oxygen is made available to the working muscles, enhancing endurance and performance.

• Improved Range of Motion - The range of motion around a joint is increased.

• Hormonal Changes - Your body increases its production of various hormones responsible for regulating energy production. During warm-up this balance of hormones makes more carbohydrates and fatty acids available for energy production.

• Mental Preparation - The warm-up is also a good time to mentally prepare for an event by clearing the mind, increasing focus, reviewing skills and strategy. Positive imagery can also relax the athlete and build concentration.

source: about.com

Dynamic Warmup should be done prior to any sports activity or weight training.