If you're beginning to exercise, you probably think exercising more--with intense durations that send your heart into overdrive--is good.  The truth is even hardcore bodybuilders don't exercise for hours on end doing endless reps.  And neither should you.  If you want to avoid painful workout injuries, use these tips to protect your bones and muscles: 

1. Start low.  Sure, it can be tempting to lift heavy weights or marathon it out on the treadmill, but training heavy when you're just starting to work out is a recipe for disaster.  To eliminate your risk for injury, start low.  For weightlifting, choose weights that causes a slight burn in your muscles when you are on your last rep (aim for 8-12 reps max).  For cardio machines, start on the lowest setting for 5 minutes and raise the setting by a couple of resistance levels if you're able to do it at a comfortable pace.  If you're sweaty but can still talk, you're in your ideal zone.

2. Don't do weights every day.  You may think lifting 40 pound dumbbells every day is the key to big gains, but it's not--many bodybuilders only train one part of their body (arms, legs, abs) once a week.  This is because your muscles need time to recover, but if it doesn't get time to recover, you can increase your risk for a painful muscle strain or tear.  Stick with training only one part of your body, such as your arms, once a week for better, safer results.

3. Start slow.  Some people assume you need to go fast while working out, but this can actually increase your risk for painful workout injuries, such as sprains, muscle tears or ligament injuries.  Going slow--and using correct form when lifting weights or doing cardio--helps dramatically reduce your risk for injury.  If you're not sure how to do a certain exercise correctly, ask for assistance from a personal trainer.  

4. Warm up first.  Although correct form is also important, warming up your muscles first--either with a slow, light jog or doing a few reps with lighter weights--is also vitally important.  This helps loosen your muscles, which allows it to adapt more easily to harder workouts.  If you don't warm up your muscles, you lose this flexibility, making it more susceptible to injury.

5. If an exercise causes instant pain, stop.  Feeling any sort of pain while working out is not normal--and no, you shouldn't work through it to make it go away.  Chances are your muscles are being stretched beyond its capacity, which is never a good sign.  Remember, if you feel any pain, stop and move onto a safer, less painful exercise to minimize your injury risk.

Remember, if you want to really get in shape, slow and steady, both in increasing reps and the length of your cardio sessions, helps you get stronger and leaner safely.  While "lifting heavy" can get you leaner and muscular faster, it also increases your risk for painful workout injuries.  Play it safe to minimize your risk for injury.