1. Not understanding the demands of their sport. For example, tennis is an anaerobic activity. If you are running two or three miles to get in shape for the tennis season you’re missing the boat.
2. Lifting weights like a bodybuilder. Three sets of eight to ten reps may build muscle, but it’s not going to make you better at throwing a baseball.
3. Not addressing the strength imbalances caused by playing your game. For example, if you are cycling hard to prepare for the road biking season you better be doing extra posterior chain work in the gym. If you’re not, you’re risking serious injury.
4. Neglecting smaller stabilizing muscles. If you’re not strengthening your gluteus medius and your vastus medialis, you’re losing performance on the field.
5. Underestimating the importance of maximum strength and power. Performance in almost every sport, including track, football, basketball, and golf, will be improved by increasing strength and power.