Want bigger legs? Stop treating every leg workout like a powerlifting meet.
Arthur Jones—the eccentric genius behind Nautilus and one of the fathers of High-Intensity Training (HIT)—believed you didn't need endless sets to build muscle.
You needed hard sets.
And when it came to legs, that could mean brutally high reps pushed until your muscles were begging you to quit.
What Was Arthur Jones’ High-Intensity Training Method?
Arthur Jones' HIT philosophy was built around a simple idea:
Train briefly. Train infrequently. Train brutally hard.
Instead of performing four or five mediocre sets of an exercise, Jones emphasized extracting everything possible from a small number of extremely demanding sets.
His famous Colorado Experiment provides an extreme example of this philosophy. During one documented leg sequence, Casey Viator reportedly performed more than 20 reps on the leg press, 20 leg extensions, and then 13 full squats—with essentially no rest between exercises and sets taken to failure.
That's strength and cardio rolled into one set.
Are High Reps Better for Building Bigger Legs?
They certainly can be.
Your legs contain both slow-twitch Type I and fast-twitch Type II muscle fibers. Fiber composition differs considerably between individual muscles, so saying the legs are simply "slow-twitch muscles" would be inaccurate.
But lower-body muscles perform an enormous amount of repetitive work throughout everyday life, and higher-repetition training gives you a brutally effective way to create muscular fatigue while still generating substantial mechanical tension.
Modern research supports one of the central ideas behind this style of training: muscle can grow across a wide range of repetition ranges.
Meta-analyses have found similar hypertrophy from lower- and higher-load resistance training when sets are performed with sufficiently high effort, although heavier weights remain superior for maximizing one-rep-max strength.
Translation?
You don't have to live in the 5–8 rep range to grow massive legs. Unless you are a strength or power athlete that needs to focus on max strength and not just size.
Why Do High-Rep Leg Workouts Work?
Imagine doing a leg press for five reps.
Now imagine doing it for 20 controlled reps when reps 15 through 20 feel like someone poured gasoline into your quads and lit a match.
As a fatiguing set continues, your body must recruit additional motor units to maintain force production. This helps explain why relatively light loads can still produce significant hypertrophy when you push them sufficiently hard.
Research comparing low-, moderate-, and high-load resistance training performed to failure found no significant difference in muscle hypertrophy between loading ranges, while heavier loads produced greater strength improvements.
That's an important distinction.
If your goal is squatting the most weight possible, train heavy.
If your primary goal is bigger quads, don't be afraid of 15, 20, or even 25 reps.
Try This Arthur Jones-Inspired Leg Workout
Forget the 25-set Instagram leg workout.
Try this:
Leg Extension — 1–2 sets × 15–25 reps
Control every rep and take the final working set to or very near muscular failure.
Leg Press — 1–2 sets × 15–20 reps
Full range of motion. No half reps. Keep going when it starts hurting.
Squat or Hack Squat — 1 set × 10–15 reps
Use a weight you can control safely. Push hard without allowing technique to collapse.
Leg Curl — 1–2 sets × 12–20 reps
Control the eccentric and squeeze every contraction.
Calf Raise — 1–2 sets × 15–30 reps
Full stretch. Hard contraction. No bouncing.
That's it.
It looks easy on paper. But it is brutally hard.
Should You Train Legs to Failure?
You don't necessarily need to hit absolute muscular failure on every set to stimulate growth. But Jones' philosophy revolved around exceptionally high effort, and that's the lesson worth stealing.
Don't turn a 20-rep set into a 12-rep set because it started hurting. There's a difference between muscular discomfort and actual muscular failure.
The Bottom Line: Stop Counting Sets and Start Making Sets Count
Arthur Jones was preaching brutally hard, efficient workouts decades before "high-intensity training" became another social-media hashtag.
Modern research doesn't validate every claim Jones made, but it does support an important part of the philosophy: muscle hypertrophy can occur across a broad spectrum of loads and repetition ranges.
So if you've spent years grinding out nothing but heavy sets of five to eight and your legs still look the same, change the stimulus.
Drop the weight. Slow down the reps. Aim for 15–25. And when your brain tells you the set is over, ask your legs whether they're actually done.
Frequently Asked Questions
How many reps should I do to build bigger legs?
Anywhere from roughly 5–30 reps can stimulate hypertrophy when sets are sufficiently challenging. For an Arthur Jones-inspired approach, try emphasizing 15–25 controlled reps on exercises such as leg presses and leg extensions.
Are 20-rep sets good for building muscle?
Yes. Research shows lower-load, higher-repetition resistance training can produce muscle growth comparable to heavier training when effort is sufficiently high.
Are high reps better for slow-twitch muscle fibers?
It's plausible that fiber type influences responses to different training stimuli, but current evidence doesn't demonstrate a clear advantage of low- versus high-load training for Type I or Type II fiber hypertrophy.
What is Arthur Jones' HIT training?
High-Intensity Training emphasizes low training volume, controlled repetitions, progressive resistance, very high effort, and substantial recovery between workouts.
Do you need heavy weights to build big legs?
No. Heavy training is particularly valuable for developing maximal strength, but research indicates muscle hypertrophy can occur across a broad range of loads.
