100 reps turn of the century: this intense new twist on the old-school "hundreds" training system will push you beyond your limits and prompt new muscle growth

Flex, March, 2007 by Jim Stoppani

One hundred reps. No, not in one workout, in one set. If you've been in the training trenches for any length of time, you've probably heard of the concept before. Maybe some old-timer at your gym even uses it once in a while.

For the most part, though, bodybuilders dismiss the technique. After all, at first glance, the reasoning behind such ultramarathon sets seems to defy logic. How could a set of 100 reps be effective for building muscle, considering how light the weight must be to complete that many reps? Compounding the issue is the lack of research on 100s, leaving us to debate the technique's worth and to use trial and error to determine its value to bodybuilders.

We say writing off 100s may be a mistake. We've found a method that will improve their effectiveness, shoot your intensity levels through the roof and force your muscles to grow in response. Here's the 411 on an all-new way to look at century sets and how to use them for massive results.

THE 30% RULE First, we should clarify an oft-misunderstood reality about the old method of 100-rep training. Typically, you don't choose a weight that allows you to complete one set of 100 nonstop reps. In standard century training, you actually choose a weight with which you can complete about 70-80 reps (i.e., 20-30% of a weight with which you can do 10 strict reps). To complete a total of 100 reps, you do as many nonstop reps as possible with that weight, and when you reach failure, rest for only as many seconds as you have reps left to perform. For example, if you reach failure on rep number 75, rest for 25 seconds and continue in that fashion until you reach 100 reps. Most bodybuilders who have used this training method do only one set per exercise and only one to three exercises per bodypart.

If you know anything about muscle, you might wonder how using such a light weight can stimulate muscle growth. After all, training with a weight that allows you to get between one and six reps is best for muscle strength gains, and training with a weight that allows you to complete seven to 12 reps is best for stimulating muscle growth. Using a weight that allows you to get more than 12 reps (or 70-80 reps, as the case may be) is best for increasing muscle endurance.

This is why many experts argue that the old 100-rep training system is a waste of time. Think about it--athletes who train for muscle endurance typically are not known for their size. Yet, the argument can be made that many bodybuilders who train with reps in the 15-25 range actually see great gains in muscle mass. In fact, a recent study reported that when subjects who were trainers added one set of 25-30 reps after doing five sets of five reps for each exercise in a strength-training program, they gained more muscle mass and strength than subjects who performed only five reps per set. Of course, 25-30 reps are far fewer than 70-100 reps, making it hard to support the old 100-rep system scientifically. All that's left to defend the method is the anecdotal reports of those who have used it in the gym.

FACTS AND FALLACIES Although we at FLEX firmly believe that the old 100-rep system does have value, we designed a new version that offers greater benefits. The new technique is based on current research that shows that going as high as 30 reps can have significant impact on muscle growth and strength, in addition to research demonstrating that high reps, as well as short rest periods, are best to stimulate growth hormone (GH) release. GH release during a workout is important for muscle size and strength increases--studies have revealed that when the GH response to training is blunted, so are gains in muscle size and strength.

The FLEX Century Program calls for using a weight with which you can achieve 20-25 reps. After reaching failure, rest just 15 seconds and continue doing as many reps as possible to failure. For most guys, this should be about 10 reps. Each time you reach failure, rest for 30 seconds before you start repping out again. Continue this pattern until you can get no more than five reps. When that happens, increase rest periods to 45 seconds. (See the "Bi Centennial" chart for a sample progression of what a new 100-rep set may look like for barbell curls.)

BI CENTENNIAL

This table outlines a sample 100-rep progression for a barbell curl.

REPS  REST (SECONDS)

 20         15

 10         30

 10         30

  8         30

  8         30

  7         30

  7         30

  7         30

  6         30

  6         30

  6         30

  5          -

This new FLEX 100s method is more intense than the older way, and it's smarter to boot. Because you use a weight with which you can complete only 20-25 reps (versus 70-80), almost all the reps from start to finish offer sufficient resistance and a challenge to the muscles for better stimulation of growth.

Also, in the original version, as fatigue sets in, it's the muscle burn that stops the set, not the inability to lift the weight. With the new system, your reps stop because you physically cannot lift the weight. And, yes, there is still plenty of burning to add to the fatigue.