100-Rep Sets

How to use marathon reps to fast-track new gains.


100-Rep Sets

One hundred. It’s crazy, right? It’s the length of a football field in yards. It’s a century. It’s enough miles per hour to earn a painful fine. In those contexts, it’s big. But in regard to reps per set, it’s huge. Dorian Yates didn’t do 100 working reps in an entire workout! You may not have ever considered cranking out a set of 100—until now.

The training style popularly known as 100s targets slow-twitch muscle fibers and permanently enhances blood flow to your muscles. In other words, it’s a unique and effective means of boosting growth. And there’s nothing crazy about that.


Rory Leidelmeyer, one of the best bodybuilders to never turn pro, used a 100s program for extended periods. Another top ’80s amateur who barely missed a pro card, Tom Touchstone, followed Leidelmeyer’s lead, as did Diana Dennis, who finished third in the 1985 Ms. Olympia. 2004 NPC Nationals winner Chris Cook plowed through a 100-rep shock set of curls and another of pushdowns on a non-arm day to drive blood to his arms and aid recovery. And Moe El Moussawi, who finished ninth in the 2008 Mr. Olympia, performed high-rep and high-volume training for years, including many sets in the 50-100 range.

Okay, so some famous and semi-famous bodybuilders repped out marathon sets. But does it work? And if so, how does it work? Advocates claim it boosts growth, enhances vascularity, and brings a subtly different look—more detailed, more distinct—to their muscles. Think of the constant polishing of a diamond to enhance its shape. Marathon sets thoroughly stress a muscle’s slow-twitch fibers during the slog of the initial approximately 50 reps. But they tax fast-twitch fibers, too, as you approach failure points on your way to the century mark. High reps also enhance circulation to the targeted muscles. In turn, improved blood flow better feeds your muscles with growth-inducing nutrients.

There are two ways to join the Century Club. You can do an entire program consisting of only three or four 100-rep sets per body part. Stick to this for periods of two to four weeks, and follow it with at least 10 weeks of a traditional workout regimen. This is a full-body growth turbocharger. Your strength may be a little depressed when you return to moderate reps, but it should bounce back within a couple of weeks.

Alternately, you can work 100s into your usual routine as a shock treatment. Do an occasional century set session for a lagging body part, or rotate such workouts so that all body parts get the treatment from time to time. Not only can this jump-start new growth, but it can also recharge your training in general, especially when you have nagging injuries. Don’t have time for your usual workout, or your joints are still reeling from your last one? Do one set per exercise for 100 reps. Such a routine will be faster and also allow you to train around injuries. You may look a little crazy and a lot weaker doing marathon sets. But, if used only occasionally, 100s is a smart way to foster heavyweight gains.


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