I've seen some crazy things at the gym. Like the guy who was jumping up and down on one leg with a loaded barbell across his shoulders. You have to wonder how he felt the next day.

If you care about how you feel the day after a workout, you'll keep both feet on the ground when you put a barbell on your shoulders. Let that be rule No. 1 in the gym. For six more, read on.

Check your ego at the door Choose a weight you can lift and lower in good form, not one you think is going to impress those around you. How do you know if you're lifting the right amount of weight? Jerking or swinging the weight into position is a sign you're overdoing it. Cut back a few pounds or reduce the number of reps during your last set so you can maintain good technique throughout the workout. Poor form not only increases your risk of injury, it sabotages your results, so choose a weight that is challenging, but also one you can lift and lower in a smooth, continuous fashion.

Too much weight isn't the only mistake. If your muscles are still raring to go at the end of your set, you might be ready to increase the weight. Use the two-for-two rule to determine when you're ready for more of a challenge. If you can complete two more repetitions than your goal for two consecutive training sessions, then you can go ahead and add weight.

Take every other day off The science behind building muscle is a two-part process. First, you overload the muscle by lifting to fatigue and then you rest it, which allows the muscle time to rebuild itself stronger. Failure to follow either of these steps means you are less likely to achieve your strength goals.

How much rest are we talking about? Twenty-four hours is all you need, so plan on resting your muscles for a full day after every workout.

If you're wondering why you see so many guys in the weight room day after day with no rest in between, chances are they are performing a split routine; working one set of muscles one day and another set of muscles the next. Split routines are a good choice, especially when you are short on time, and since they follow the "every other day" rule, they're also effective as well as efficient. Reduce momentum To get the full benefit of your workout, take two seconds to lift the weight and three to four seconds to lower it back to the starting position. Any faster and you run the risk of allowing momentum to make the lifting and lowering of the weight easier. That added ease might allow you to stack more weight on the bar, but the extra weight might not bring about the results you want.

Too much momentum can also lead to injury. Adding speed to a joint already struggling to cope with additional weight is a good way to get to know your family doctor a bit better. Don't hold your breath It's a natural response to hold your breath upon exertion, but, in fact, the opposite is what you should be doing. Exhaling as you lift keeps your blood pressure from rising and reduces the discomfort and possible injury associated with straining during activity.

That doesn't mean you have to avoid working hard in the gym. Effort shouldn't be confused with straining. If you concentrate on exhaling as you lift the weight and inhaling as you lower the weight, you'll establish a regular breathing pattern that doesn't detract from the task at hand.

When in doubt, choose free weights Weight machines like the leg press and Smith machine are fine for beginners, but once you have the hang of good technique, choose a barbell or a set of dumbbells, not a machine, to add challenge to your exercise. Free weights force the body to balance and support itself while lifting, which is closer to how you operate in real life both on and off the athletic field. Plus, activating the muscles needed to support balance when you lift weight improves core strength and endurance, which is an added plus.

The only exception to this rule is directed toward those who need the added support weight machines offer, like novice lifters, anyone with a sore back or someone who is attempting to lift a heavy weight without the aid of a spotter.

Lift with a goal in mind Before you embark on a weight-training program, decide what you want to achieve. Do you want big muscles that look great in a T-shirt, strong muscles that can lift heavy weight or are you looking to improve muscular endurance defined as the ability of the muscle to withstand multiple repetitions? Once you decide what you're training for, follow the guidelines inset regarding the recommended number of repetitions and sets.

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LIFT OFF TO YOUR GOALS

These guidelines will help you tailor your workout to the type of fitness goals you're looking to reach.

GOAL: STRONGER MUSCLES

Number of exercise repetitions Six or fewer

Number of sets Two to six Length of rest between sets Three to five minutes

GOAL: BIGGER MUSCLES

Number of exercise repetitions Six to 12

Number of sets Three to six Length of rest between sets Thirty to 90 seconds

GOAL: MUSCLE ENDURANCE

Number of exercise repetitions Twelve or greater

Number of sets Two to three Length of rest between sets Thirty seconds