21s in Bodybuilding Lore


What teen or young lifter hasn’t been seduced by the idea of bigger biceps? Indeed in the bodybuilding universe of both males and females, no pose is more iconic that the front or back double bicep pose.

A difficult set of muscles to grow, except of course for the genetically gifted, the biceps have been subjected to a variety of tortuous and bizarre experiments aimed at growth. The subject of today’s short post, being one such example.

As a quick recap, ’21s’ is the name generally given to a set of bicep curls wherein seven partial reps are performed at the bottom of the movement, seven more at the top of the movement before finally, seven full reps are performed as one continuous set.

Long associated with Arnold Schwarzenegger’s repertoire of bodybuilding tricks, the purpose of today’s post is to highlight a potentially different story. A story that, in an odd occurrence, includes Arnold as a side character, away from the main spotlight.

The Traditional 21s Narrative


In the scant sources dealing with 21s, the story goes as follows. Arnold sought to increase his biceps to greater and greater sizes. A man known for his unique style of training that was high in intensity, he came across the idea of combining partial and full repetitions. Thus, 21s for biceps were created.

Said protocol was kept hidden within the confines of the elite bodybuilding community until he published his Encyclopaedia of Modern Bodybuilding in 1985. There he revealed the secret of 21s for adding inches to your arms. Prompting a flurry of impersonators around the globe, yours truly included.

Though Arnold never laid claim to the exercise, his publication of it has made him synonymous with it regardless. A point which leads us to ask, who actually promoted this method in the first place?

Two Alternative Histories

In researching this topic, I’ve come across two competing narratives. One complete conjecture on my part and the other, a testimonial from the supposed inventor! We’ll start with the latter, and most likely, more truthful of the two.

Writing in the early naughties, Dr. Ron Laura, a bodybuilding ‘guru’ of many decades experience, laid claim to inventing the ’21s’ or Platoon System of training. Through the magic wizardry of the Wayback Machine, I can reprint Dr. Ron’s claim in full:

“As incredible as it may sound, I devised my first Matrix Principle when I was only seven years old, while living with my family in Boston and training with my brother, James, eleven years older than I.

He was a serious gridiron footballer and trained with a few team members in our basement gym in which most of the machines were designed by our father who was an extraordinarily talented metalworker and machinist.

To build muscle power and size for arms my brother would have his friends do 3-5 sets of 20 repetitions in the curl, for example, using heavy weights and a bit of body sway to ‘cheat.’

Trying to keep up with them, I used a 24” long bar my father had made for me on his lathe, weighing about 3.5 kg.

Given that my brother and his team mates would perform the ‘cheating ‘ reps at a brisk pace, I would do my best to imitate them by doing 7 reps half-up, then 7 reps halfway down and up, followed by 7 full reps.        


My brother and his friends used to laugh at me, on the assumption that what I was doing was no more than a little boy’s ‘cop-out’; that is what they thought anyway until they tried the partial-rep sequence and realized I had serendipitously come up with a great technique which actually increased the intensity of the exercise.

We called my idea the ‘21 system’ and the whole group of us soon used it to do every exercise, with impressive results for them and me.

The following year my brother went to California to work at American Health Studios, where he introduced my 21-technique to a group of servicemen who wanted a quick and effective routine that they could execute together in a circle as a way of motivating each other.

Consequently, my 21 System became known to some as  ‘The Platoon System’ and in another of its guises has been used by many bodybuilders worldwide ever since, without knowing it was ‘invented’ by a seven year old boy, in a cellar home gym in Boston, U.S.A.

By the time I was in my teens I had developed twelve different partial-repetition techniques, which in a slightly revised form, were published nearly twenty years ago in my book The Matrix Principle,  whose title reflected the name that I had by this stage given to my extended system of 21s.

 In my competitive days I regarded this first program of 12 Matrix techniques as my ‘secret weapon’ and relied upon it almost solely.                                   

It was not long before I became a champion powerlifter, eventually bench pressing a world record 350lbs at a body weight of 148lbs in 1963.

The rest, as the saying goes, is history……….

I continued testing and developing effective variations of my original twelve Matrix techniques and have now created 48 Matrix Principles on patterns of partial-repetition movements for every body part.

With a growing interest in competitive bodybuilding I became close friends with Joe Weider, the legendary trainer of champions, from whom I leaned much and to whom I owe much of my success in the world of bodybuilding. Weider employed me as a ‘ghost writer’ and a feature writer for Muscle and Fitness Magazine, as well as Flex.”

If said story is true, it is likely that Weider or possibly Dr. Ron helped to pass the exercise on to Arnold and his bodybuilding cohort.

Another Explanation


My own conjecture, is that Wag Bennet, an English physical culturist famed for his generosity and interest in the sport of bodybuilding, may also have had a part to play. You see, aside from assembling one of the most amazing gyms I have ever seen (click here), Wag would often house and mentor bodybuilders who came to visit him in England.

This included, quite famously, Arnold Schwarzenegger, who lived with Wag for a short period in the mid-1960s. A few years before Arnold and Weider struck up their profitable and fruitful bodybuilding partnership. Under Wag and his wife’s tutelage, Arnold train at Wag’s gym, soaked up as much as possible, and if stories are to be believed, ate like a horse.

Why this is important is that in an updated piece published on his own personal website, bodybuilder Lee Labrada mentioned that Wag introduced him to 21s training when Labrada was touring England. I’ve been unable to verify where Wag learned of this method but it nevertheless presents an interesting insight into how bodybuilding techniques were transmitted in the pre-internet era outside of magazines.

Who to Believe?

Sadly I have no idea! Given the weight of the evidence, it appears that Dr. Ron’s claim holds more weight. Nevertheless I like the idea of Wag Bennet influencing Arnold before he took the US, and subsequently the world, by storm.

What do you think? Let us know in the comments below!

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