Improve Your Fitness Level
REGULARITY—Set up a regular schedule and work out every day, or at least 3-4 times each week. It's not good to take too much time off between workouts—what you don't use, you lose.
OVERLOAD—For a muscle to get stronger it must work harder than it does at rest. This means making your heart beat faster and your breathing increase during aerobics, doing more repetitions of an exercise or lifting more weight. If an exercise feels too easy it probably is, and chances are you won't improve. But remember, don't overdo it. "No pain, no gain" is a myth!
SPECIFICITY—Exercise is specific. For example, aerobic exercises won't build flexibility. And, stretching exercises won't make your muscles stronger. To be flexible you have to stretch, and to be strong you have to make your muscles work hard. And, to be good at a certain sport you have to practice that sport.