The Toughest 15 Minute Muscle Building Workout Ever

Serious about packing on quality muscle size with just four 15-minute workouts a week? The 6-12-25 Workout is designed for individuals seeking maximal muscular development by trashing the Type 11b, Type 11a and Type 1 muscle fibers in one giant 43-rep set.

Warning: This is not for anyone with less than one year of consistent weight training experience. Nor is it for anyone not prepared to enter the hurt box, because this workout demands a high level of discomfort, focus and motivation.

The 6-12-25 method was introduced to me while attending Charle’s Poliquin’s 5-Day Hypertrophy Bootcamp, and I provided an extra tough twist to tailor it to any skinny hardgainer who wants to explode new muscle off his frame by exploiting the less-is-often-more training theory.

The Premise

The 6-12-25 Workout incorporates a variety of loads across the neural-metabolic continuum to stimulate the three primary muscle fibers required for muscle size and muscle growth: Type 11b, Type 11a and Type 1 muscle fibers. If you rely on training methods that only train one or two of these fibers, you will not experience maximal muscle growth because you’re not recruiting all the available muscle fibers for growth.

Due to the brief rest periods in this workout, you’ll also produce significant lactate which will aid in the production of growth hormone (GH) which increases the potential for fat loss and muscle growth.

How Does The 6-12-25 Workout Program Work?

You will perform one big drop set, also known as a “giant set” or “tri set” or “circuit” which combines three different exercises for the same muscle group. You’ll do 6 reps with the first exercise for strength gains, then you’ll do 12 reps with the second exercise for hypertrophy gains and then you’ll do a third exercise for 25 reps for muscle endurance gains. Combining the three into one mega giant set with short rest periods make this one hell of a way to get out of a strength, hypertrophy, or fat loss rut!

The secret to making this workout effective is selecting the correct loads, i.e. weight selection. You must choose loads that reflect your 6 rep max, your 12 rep max, and your 25 rep max. In other words, you must pick a weight that will result in an all-out war on the 6th rep, 12th rep and 25th rep. If you can steal an extra rep, that’s awesome. If you can steal two extra reps or more, you miscalculated your loads too light. If you fail one rep shy of your goal reps, no worries. If you fail two or more reps shy of your goal reps, you miscalculated your loads too heavy. Fix it in your next workout.

You will perform two body parts during each workout using a training split that looks like this:

Day 1: Shoulders

Day 2: Biceps & Triceps

Day 3: Off

Day 4: Quads & Hips

Day 5: Off

Day 6: Chest & Back

Day 7: Off

Repeat

Go through this cycle a minimum of three times (three weeks) and a maximum of six times (six weeks). Doing it for longer will result in diminishing returns and adaptation.

The Most Important Variable – Tempo!

The first exercise in the workout will be done with a 40X0 tempo.

The second exercise in the workout will be done with a 30X0 tempo.

The third exercise in the workout will be done with a 20X0 tempo.

If you’re unfamiliar with tempo - the subtle changes you’ll experience in this workout will make your muscles scream for dear life. Tempo is one of the most under-utilized variables when it comes to muscle growth. What does 40×0 look like on the gym floor?

4 is the eccentric portion or the negative. You will take four seconds.

0 is the bottom portion in a stretched position. You will pause for zero seconds.

X is the concentric or lifting portion. X means you will explode.

0 is the contracted position. You will pause for zero seconds.

Your load selection is dictated by the tempo and the number of reps you must hit.  Assuming this is a new lifting protocol, it will take a workout or two to choose the right weights to get this right. Every single one of these sets should be very, very hard to finish, which is why the workout is short in duration. You will rest 10 seconds between exercises and 120 seconds between giant sets. If you don’t abide by the rest period you’ll affect lactate production and miss out on the fat loss benefits.

Modifications based on training age

Beginners (anyone with less than one year training experience who insists on trying this) will do two giant sets for a 10-minute workout per body part.  Intermediates (anyone with one to four years training experience) will start with three giant sets for a 15-minute workout per body part. After a few weeks you can try to do a fourth giant set. Advanced lifters can take a shot at four or five giant sets providing a 20 to 25-minute workout per body part. Don’t be surprised if you need to stop after three giant sets though! This is normal if you choose your loads correctly.

Here is the four-day program!

Day One: Shoulders & Abs

A1. 6 reps: Standing Military Press

Rest 10 seconds

A2. 12 reps: Seated Dumbbell Presses (elbows facing forward)

Rest 10 seconds

A3. 25 reps: Prone Dumbbell Lateral Raises on 45 Degree Incline Bench

Rest 120 seconds. Repeat 2-5 times

A1. 6 reps: Weighted Hanging Leg Raises

Rest 10 seconds

A2. 12 reps: Weighted Cable Crunches

Rest 10 seconds

A3. 25 reps: Floor Crunches

Rest 120 seconds. Repeat 2-5 times

Day Two: Biceps & Triceps

A1. 6 reps: Standing Dumbbell Curls

Rest 10 seconds

A2. 12 reps: Incline Cable Curls

Rest 10 seconds

A3. 25 reps: High Cable Curls

Rest 120 seconds. Repeat 2-5 times

A1. 6 reps: Weighted Dips

Rest 10 seconds

A2. 12 reps: Lying Dumbbell Extension

Rest 10 seconds

A3. 25 reps: Overhead Rope Extension

Rest 120 seconds. Repeat 2-5 times

Day Three: Off

Day Four: Quads & Hips

A1. 6 reps: Medium Stance Squats

Rest 10 seconds

A2. 12 reps: Bulgarian Split Squats with Weight

Rest 10 seconds

A3. 25 reps: Leg Extensions

Rest 120 seconds. Repeat 2-5 times

A1. 6 reps: Medium Stance Deadlifts

Rest 10 seconds

A2. 12 reps: Leg Curls

Rest 10 seconds

A3. 25 reps: Back Extensions

Rest 120 seconds. Repeat 2-5 times

Day Five: Off

Day Six: Chest & Back

A1. 6 reps: Incline Bench Press

Rest 10 seconds

A2. 12 reps: Flat Dumbbell Press

Rest 10 seconds

A3. 25 reps: Cable Flys

Rest 120 seconds. Repeat 2-5 times

A1. 6 reps: Bent Over Rows

Rest 10 seconds

A2. 12 reps: Neutral Grip Chin Ups

Rest 10 seconds

A3. 25 reps: Rope Rows

Rest 120 seconds. Repeat 2-5 times

Day Seven: Off then repeat

Want to see the entire 6-12-25 muscle building workout on video?  Here is the entire video series below:

1 Response to “The Toughest 15 Minute Muscle Building Workout Ever”


  1. Ezravdb

    Awesome content again Vince, thanks for laying it all out again.

    the videos itself was clear enough, but you made it even better :)