1.12 Rep rule

The typical weight training program features twelve reps, the conventional wisdom is that this somehow the best number of reps for gaining muscle. In reality, following this rule does not provide your muscles enough tension to grow as well as they potentially could.

Heavier weights provide the maximum gains in strength and muscle mass. Longer tension means more muscle growth. This is because it promotes the strengthening of the muscle fibers (which also increases endurance).

Eight to twelve reps does not give you the tension levels that can be achieved by less reps with heavier weights, or the longer tension that comes from light weights with more reps. To create all types of muscle growth, change up your routine - both in terms of repetitions and the weights you use.

2. Three Set rule

While three sets is perfectly fine, it is also not a magic number for weight training. The number of sets to do should have more to do with what you hope to accomplish, and not an old rule which may or may not work for you. Just keep in mind that the more reps you do in a set, the fewer sets. The converse is also true; the total number of reps should remain equal.

3. Three to four exercises per group

The truth is this is a waste of time. Combined with twelve reps of three sets, the total number of reps amount to 144. If your doing this much reps for a muscle group your not doing enough. Instead of doing too many varieties of exercises, try doing 30 to 50 reps. That can be anywhere from 2 sets of 15 reps or 5 sets of 10 reps.

4. My knees, my toes

It is a gym folklore that you "should not let your knees go past your toes." Truth is that leaning forward a little too much is more likely a cause of injury. In 2003, Memphis University researchers confirmed that knee stress was almost thirty percent higher when the knees are allowed to move beyond the toes during a squat.

Squatters are shifting the strain to their lower backs, which is actually far worse than letting their knees pass that "no-go" line of the toes.

Try to think more about the position of your torso, and not so much about your knees. Keep your torso as upright as you can during lunges and squats. This means less stress on your back. A tip for staying upright: prior to squatting, press your shoulder blades together and keep them there. While squatting, try to keep your forearms at a right angle to the floor.

5. Lift weights, draw abs

The most important muscle group is not necessarily the transverse abdominis. Depending on which exercise you are doing, the most important muscle group can be any group at all. Most of the time though, the body will instinctively call the appropriate muscle group onto the field to keep the spine well supported. Focusing on the wrong muscle group can actually cause injuries, not to mention keeping you from lifting as much as you otherwise could.