Warming Up For Exercise
Warming up prepares the body for physical action. The process involves stretching exercises and physical activities that gradually heat the muscles and elevate the heart rate. A brisk walk, slow jog, jogging or hopping in place, rope jumping, and selected calisthenics will raise the heart rate and increase muscle temperature. Participants should break out in a sweat during the warm-up. This indicates that heart rate and body temperature have increased to some extent and the individual is ready for more vigorous activity. The warm-up should last 5 to 10 minutes.
Increasing the heart rate gradually during the warm-up period is most important. This allows the circulatory system to adjust to the load. If the heart rate elevates suddenly, circulation cannot adjust rapidly enough to meet the oxygen and nutrient demands of the heart muscle. The effects of this lag time are abolished in about 2 minutes, but this practice can be potentially hazardous, particularly for those with compromised circulation caused by latent or subclinical heart disease. Even the healthy heart may be affected by eliminating this important phase of warm-up. One study showed that each of 44 healthy male subjects, ages 21 to 52 years, had normal electrocardiogram (ECG) responses to running on a treadmill when they were allowed a warm-up consisting of 2 minutes of easy jogging. However, 70% of the group developed abnormal ECG responses to the same exercise when they were not allowed to warm-up.
Warm-up may be specifically tailored to the activity to be performed.
For example, joggers may warm-up by slowly jogging the first 1/2 to 3/4
mile, gradually speeding up to the desired pace. Cyclists, swimmers,
cross country skiers, and rope skippers may use the same approach.
Passive warm-up techniques, such as massage, sauna baths, steam
baths, hot showers, hot towels, and heating pads, should not be used as a
substitute for an active warm-up. These techniques may precede an
active warm-up if you feel stiff and sore from the previous workout.
Cooling Down From Exercise
The cool down is as important as the warm-up. Cool down should last 8 to 10 minutes and consist of two phases. The first phase involves approximately 5 minutes of walking or other light activities to prevent blood from pooling in the muscles that have been working.
Light activity causes rhythmic contractions of the muscles, which in
turn act as a stimulus to circulate blood from the muscles to the heart
for redistribution throughout the body. This boost to circulation
following exercise, often referred to as the muscle pump, is essential
for recovery and shares some of the burden of circulation with the
heart. The muscle pump effect does not occur if a period of inactivity
follows exercise. An inactive cool down forces the heart to work at a
high rate to compensate for the high volume of blood returning to it
because of blood pooling in the muscles. The exerciser runs the risk of
dizziness, fainting, and more serious consequences associated with
diminished blood flow to vital organs.
Light physical activity after exercise also speeds the removal of
lactic acid that has accumulated in the muscles. Lactic acid is a
fatiguing metabolite resulting from the incomplete breakdown of sugar.
It is produced by exercise of high intensity or of long duration.
The second phase of cool down should focus on the stretching
exercises performed during the warm up. Most participants find that
stretching after exercise is more comfortable and possibly more
effective because the muscles are heated and more elastic.
Many activities contribute to one or more components of health related physical fitness. Activity selections should be based on objectives, skill level, availability of equipment, facilities, instruction, climate, and interest. Any rhythmic, continuous aerobic activity that uses large muscle groups, and can be performed for an extended period of time is suitable for the attainment of health and fitness.
The president’s council on physical fitness and sports (PCPFS)
enlisted the aid of seven experts to evaluate 14 popular physical
activities for their contribution to physical fitness and general well
being. Although this assessment occurred several years ago, the ratings
are as valid today as when they were originally conceived.
Selected sports have been evaluated for their contribution to the
health related components of physical fitness. Lifetime sports (such as
tennis, badminton, and racquetball) are more conducive for fitness
development than team sports (such as volleyball, soccer, softball, and
basketball) because fewer players are needed. Ideally, fitness should be
developed and maintained primarily through self paced activities (for
example, jogging, cycling, walking, and swimming), but the challenge
inherent in sports may be necessary to sustain the fitness program for
some people. Lifetime sports are challenging and fun, and they inject
variety into the program.
However, fitness attained from these activities depends on skill
level and a willingness to exert maximal effort in competition. The
orthopedic demands of these activities may be greater than a sedentary
beginner can tolerate. Quick stops and starts, bursts of high intensity
activity, sudden changes of direction, and rapid twists and turns place a
great deal of stress on the musculoskeletal system. The physically fit
can handle the aerobic and musculoskeletal requirements of active
sports. Attempting to “play yourself into shape” is a mistake. With
knowledge of the principles of exercise, warm-up, cool down, and the
contribution of various physical activities to physical fitness, you can
design an exercise program using.