By Daniel G. Graetzer, Ph.D.
Faculty Member, School of Health Sciences
According to researchers Frank Shellock and William Prentice, performing warmups and stretches prior to strenuous exertion are critical to improving athletic performance, alleviating muscle soreness, and preventing injury. However, Kimberly Burke of Colorado State University notes that many recreational and competitive athletes often neglect proper warm-up and cool-down sessions and fail to gain their full benefits.
Why Are Warmups Necessary?
Warmups prepare an athlete physically and mentally for practice or competition. The American Heart Association says that warmups also increase body temperature, blood circulation, and speed of muscle contraction, while increasing the efficiency of both aerobic and anaerobic metabolism within working muscles.
Generally, an increase in internal body temperature of 1 to 1.5 degrees Celsius accompanied by mild sweating is generally sufficient to gain these temperature-related warm-up benefits. Psychologically, a warm-up period of 10 to 15 minutes has been shown to relieve tension and relax athletes so they are better able to concentrate, notes Pez Cycling News.
The Three Categories of Warmups
Warmup techniques are generally classified into three major categories: passive, general and specific.
Passive warmups, according to researcher David Bishop, involves raising the body’s temperature through external sources such as saunas, heating pads or whirlpools. The main advantage of a passive warm-up is that superficial muscle temperature can be increased with a minimal depletion of critical carbohydrate (glycogen) reserves within muscle cells.
General warmups increase deep muscle temperature through active movements of the major muscle groups, notes Brad Walker of StretchCoach. Calisthenics, stationary bicycling, jogging, jumping rope and even kicking a hacky sack elevates deep muscle temperature much better than passive warmups.
Specific warmups, says Precision Performance Physical Therapy, focuses on preparation and repetition of the muscular movements that will be used during competition. Warming up by throwing a softball or hitting a tennis ball at a reduced level of intensity effectively elevates muscle, connective tissue, and joint fluid temperature and also create muscle memory. Ideally, increasing body temperature to the point where the skin is warm and flushed, sweating has begun, and heart rate and ventilation rate have noticeably increased should precede pre-exercise stretching.
Stretches Should Be Performed after Warmups to Improve Static and Dynamic Flexibility
Kai Simon Fitness recommends that athletes perform a 10-minute stretching session after a warmup and immediately before exercise to improve static and dynamic flexibility. The stretches will increase an athlete’s flexibility and prepare the body for the physical stressors about to be encountered.
Static flexibility, according to Better Me, is the capacity of a joint to move passively throughout a range of motion. It is important for injury prevention if a muscle is forced to stretch beyond normal limits.
Dynamic flexibility, notes Kirsten Nunez of Healthline, is the joint movement caused by muscular movement. It occurs in the midrange of static flexibility and is important for optimal athletic performance.
For example, a sprinter with tight hamstrings will have a shortened stride length and a reduced running speed. Flexibility is very joint-specific, meaning that an athlete may have good flexibility in the legs and back but poor flexibility in the shoulders and other areas of the body.
To overcome this problem, stretching exercises should be concentrated on the joints that are involved in the movements that will be required for participation in a certain sport. Some sports also require different parts of the body to move within a certain range of motion. For instance, the hyperextension of certain joints is critical in sports such as gymnastics.
Stretching Techniques and Categories
According to researchers Stanley Sady, Morris Wortman and Daniel Blanke, stretching techniques are generally classified into three major categories. These categories are ballistic, static and proprioceptive neuromuscular facilitation (PNF) stretching.
Ballistic stretching, which utilizes repetitive bouncing movements according to Set for Set, is the oldest and potentially most dangerous stretching method. Grass-catchers and other quick stretches have a high potential for injury, set off a stretch reflex that may make muscles tighter, and should not be utilized, especially by children.
Stretch Coach notes that static stretching involves passively stretching a muscle to the point of discomfort. Static stretches should be conducted three to four times within each sport-specific range of motion; each stretch should be held a minimum of 30 to 45 seconds.
Proprioceptive neuromuscular facilitation (PNF) stretching, says VeryWellFit, was first used for treating arthritic patients. It is currently considered one of the most effective methods to improve dynamic flexibility in athletes.
WebMD notes that PNF stretching builds strength as well as flexibility by alternating 10-second periods of contraction followed by 10-second periods of relaxation at increasingly greater joint angles. For example, PNF stretching can be used to increase hamstring flexibility by having an athlete lie on his/her back while a partner passively flexes that athlete’s right or left leg at the hip joint until tightness is felt.
The knee should be then extended as much as possible, and the ankle should be flexed to 90 degrees to isolate the hamstring muscles. The athlete can then contract the hamstrings and push as hard as possible against the partner’s resistance for 10 seconds.
After that, the athlete relaxes the hamstring muscles for 10 seconds. The partner then further increases hip joint flexion, and the athlete repeats the PNF stretch. This contraction-relaxation sequence can be repeated four to six times or until the endpoint of the range of motion is reached.
The PNF contraction-relaxation procedure utilizes nervous system receptors located at the muscle-tendon junction, called Golgi tendon organs, that are sensitive to changes in both muscle length and muscle tension. Stretching Exercises Guide says that PNF stretching stimulates a protective action of the Golgi tendon organs called autogenic inhibition during contraction, “fooling” them to cause a reflex relaxation of the same muscle group to avoid potential muscle tearing when the end point in the range of motion is reached rapidly.
Although exciting new research is underway, the current thinking is that the reflex relaxation created by stimulation of the Golgi tendon organs apparently checks and overrides impulses coming from the muscle spindles. According to the American Council on Exercise (ACE), muscle spindles are receptors located alongside the belly of the muscle, are only sensitive to muscle length (not tension) and cause a contraction of the same muscle group being stretched to resist muscle stretch if left unchecked by the Golgi tendon organs.
According to Net Journals, PNF stretching has been proven to be extremely effective at increasing dynamic flexibility while enhancing injury prevention mechanisms in joints that are predisposed to muscle tears. This type of stretching can be used to enhance flexibility in essentially any muscle group, including the shoulders, arms, legs, groin and low back. Various sport-specific PNF stretches can be designed for essentially any activity by imitating the muscular range of motion that an athlete will encounter.
Warming Up and Stretching Are Vital to Prevent Injuries
The combination of warmups and stretching are vital for any exercise session, whether one is exercising in a gym or preparing to compete in a sport. Without proper warmups and stretching, an athlete risks either temporary or even permanent injury.