A warm-up is usually performed before participating in technical sports or exercising. A warm-up generally consists of a gradual increase in intensity in physical activity (pulse raiser), a joint mobility exercise, stretching and a sport related activity. For example, before running or playing an intense sport one might slowly jog to warm muscles and increase heart rate. It is important that warm ups should be specific to the exercise that will follow, which means that exercises (of warm up) should prepare the muscles to be used and to activate the energy systems that are required for that particular activity. The risks and benefits of combining stretching with warming up are mixed and in some cases disputed. Warming up prepares the body mentally & physically.
Types of warm-up:
Ballistic Stretches: Ballistic Stretches (involving bouncing or jerking) are purported to help extend limbs more during exercise to allow an individual to be more agile and flexible. However this type of stretching can cause injury and is not generally recommended.
Static Stretches: Flexing the muscles to help prevent injury and allow greater flexibility and agility. Note that some sources discourage static stretching as muscles are more prone to damage if stretched while cold. Static stretching for too long can also weaken the muscles temporarily
Benefits of 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. As blood temperature rises, the binding of oxygen to hemoglobin weakens so oxygen is more readily available to working muscles, which may improve endurance.
Improved Range of Motion – The range of motion around a joint is increased.
Why we need to do warm-up and cool-down?
The start of a warm-up is a signal to the body that exercise is about to commence, a form of mental preparation. The warm-up also is a trigger to the neuromuscular system that the linkages between the nervous system and various muscle groups will be utilized shortly. While a lack of available training time and a desire to begin the substantive parts of the training or activity are the most common reasons as to why some warm-ups are not thorough, numerous sports science studies have confirmed that a thorough warm-up will reduce the rate of injury while increasing overall athletic performance.
While the intensity and the duration of a warm-up will vary due to individual circumstances, evidence that the desired increase in cardiovascular activity and an increase in internal body temperature consistent with muscle warmth is the generation of a light-to-moderate degree of perspiration. A minimal warm-up, where the athlete is not engaging in a specific or targeted activity, will generally last from eight to 10 minutes. This warm-up might include very easy jogging or vigorous walking, with a pronounced arm swing to increase the heart rate. When the warm-up is conducted in cold weather, the body may require a longer period of time to produce the desired cardiovascular and thermoregulatory effects. The athlete may conduct some sport-specific warm-up movements to provide benefits.
Once the body has been activated through a basic warm-up, the athlete may engage in a stretching program. All skeletal muscle groups are more vulnerable to strain and tearing if the muscles are aggressively stretched without a warm-up. The most effective method of stretching, the static stretch, requires the athlete to maintain the muscle structure in the extended position for between 20 and 30 seconds. It is particularly important to conduct the static stretches for the muscles that will be primarily engaged in the activity ahead.
The primary goal of the cool-down phase is to gradually reduce the level of activity achieved by the body during either training or competition. An effective cool-down program will gradually reduce the person’s heart rate to its normal level, and it will assist in the efficient removal of metabolic wastes, such as lactic acid produced by the cardiovascular system. Just as importantly, a proper cool-down will ready the muscles for the next training session or activity. There is no conclusive scientific proof that cooling down necessarily reduces a condition known as delayed onset muscle soreness. This condition frequently occurs to athletes whose muscles have been subjected to a strenuous workout, with the onset of muscle discomfort not present for between 24 to 48 hours after the event. However, overall muscle health is promoted through the cool-down process whether or not the muscle subsequently becomes sore.
A simple and effective means of cooling down is to continue to exercise at a low intensity level for approximately 10 minutes for every hour of vigorous exercise, immediately at the conclusion of the primary exercise. A gap between the higher intensity levels is counterproductive to the goals of a gradual return to resting levels. A stretching routine of the same extent and intensity level to that employed in the warm-up is also useful, as the muscles are properly warm from the activity.
Pictures of warm-up and cool-down: