Growth spurts happen to all kids, but they can wreak havoc on your athletic life. Your body will go through periods of rapid vertical growth punctuated by periods of "filling out" as your muscles catch up to your bones. Good nutrition and regular sleeping habits will help you maintain your activity level despite the temporary weirdness happening in your body, but planning your athletic interests around your growth spurts can actually make the most of the situation and make you a better all-around athlete.
During your vertical growth phases, you may get skinnier as you get taller because your bones can grow faster than your muscles, and your body's using too much fuel to pack anything away as fat. Your body will be longer and leaner than usual, so use this opportunity to improve your cardiovascular health and build endurance with running, swimming and dancing. Your strength-to-weight ratio will be better than ever, so you may suddenly find it easier to keep up with the cross country team. Your longer reach and streamlined body will be an advantage in the pool, and dance relies on long lines for the proper aesthetic. These activities also teach a certain amount of agility and grace so you can avoid the awkward coltish look associated with pubescent teens.
Between vertical growth spurts, your body will take some time out to "fill out" -- that is, add the bulk that goes with your height, eliminating the "string bean" look. Since your body is predisposed to gaining mass during this phase, use this opportunity to build muscle by participating in weight training, gymnastics, wrestling, rowing or other strength-based sports. Bulk can appear as either fat or muscle, and doing resistance training help ensure that it takes the form of muscle. Boys especially may gain muscle rapidly during this phase as testosterone levels increase, so stretching is important to maintain flexibility. Stretch gently and carefully to avoid injury while your body is in a state of flux.
The American Dietetic Association says that an active 13-year-old may need up to 2,600 calories per day to compensate for activity and growth, but your doctor is the best person to tell you how many calories it takes to fuel your specific body with your specific activity. You may also need additional calories during heavy training, so ask your coach for her recommendation. A balanced diet is important -- 55 percent of your calories should come from carbs like fruit, vegetables and whole grains, because these provide energy. Lean proteins like fish and poultry should make up 15 to 20 percent of your diet, because protein is important for growth -- which you're doing a lot of these days. Fats are also important for growth, and they play a role in brain function -- about 25 to 30 percent of your calories should come from olive and canola oil, seeds and nuts and fatty fish.
Because your bones grow faster than your muscles, you are at a higher risk of injury. Heavy impact, improper form or even stretching too far can cause your muscles to disconnect from the bone and cause pain that will take you out of the game for a few weeks. Always wear the proper shoes for whatever sport you're doing, and learn proper form -- these two things alone can go a long way towards impact protection. Don't attempt to teach yourself anything athletic -- learning from a pro is the best way to do it right the first time rather than practice bad habits that will only hurt you in the long run.