Lift Heavy to Stimulate Muscle Growth

Dr. Bill Kraemer, a professor of kinesiology at the University of Connecticut, recently reported on a study that found women tend to lift half--or even less--of what they could lift in the gym. The result improved slight but not much for women who worked with personal trainers. So ask yourself this: Are you maximizing your efforts in the weight room?

The most effective way to stimulate muscle growth is to lift heavy. As a rule of thumb, use a weight load that will fatigue your muscles in about 8 to 10 reps. If you're looking to increase strength and power, go for a 4 to 6 rep range. And when using a lower the rep range with the heavier weights, remember to increase your rest time between sets as well.

But exactly what weight will stimulate muscle fibers and make your muscles grow? Lifting too much weight without enough reps, or too light a weight with too many reps, will get you nowhere.

In the April 2006 issue of Muscle & Fitness, Mark Casselman wrote that maximal hypertrophy occurs with loads from 80 to 95 percent of your one-rep max, which is the maximum amount of weight you can lift for a single repetition of a given exercise.

You can determine what weight you should be lifting by first establishing your 1 rep max. If you don’t have a spotter to help you find out your magic number (and don't ever attempt to try without a spotter), you can use a number of formulas out there to guesstimate your 1RM. Here's an example:



Based on this formula, if I can bench press 65 pounds for 10 reps, my estimated one rep max for this exercise would be 87 pounds. It's not an ironclad number, but it's a good ballpark figure if that's all you have to go by. The poundage can then be changed as needed to perform the number of reps called for by your training protocol. According to the National Strength and Conditioning Association, this translates into a weight you can lift anywhere from 6-12 times to muscle failure. After doing my own math, I am off about 5 pounds, but I'm lifting pretty close to what I should be lifting--at least when it comes to the bench press.

But weight training requires a mix of moderate to heavy training, so even if you find the weight and perfect rep range, it's important to use periodization in your resistance training program by alternating the cycles of weight lifted with total repetitions. Include training sessions with lighter weights for higher reps, moderate weight for moderate reps, and heavy weights for lower reps to maximize muscle fiber growth.