Double Barrel

A double-barrelled gun gives you two shots, one right after the other. “Double Barrel” is built around two days in the gym: each workout trains the whole body, so chest, back and legs are loaded twice a week. Pick your two days and start with the intro week.

For beginners who can get to the gym two days a week. 2 workouts a week, 7 exercises each: in Base every weighted exercise is done for 12 reps, in Build for 10, with 6 sets a week for chest, 6 for back and 10 for legs. Two 4-week stages: in Base the load rises week by week, in Build it moves in a wave with a step back in week 3. In Build two exercises are swapped for others and the rest stay the same; the reps and the loading pattern change. Once you have a third day, the next step is “Bodyworks”.

With two workouts a week, each one trains the whole body, so chest, back and legs are loaded twice a week. The app calculates the weight for each set from your max and raises it in a 4-week wave, with the first week as an intro week. Every set ends with reps still in reserve.

Method: Full body twice a week.
Muscle growth depends above all on the number of sets per week; with volume equal, frequency makes little difference. With two days in the gym, each session trains the whole body, and chest, back and legs are loaded twice a week.

What studies found:

• With weekly volume equal, training frequency has little effect on muscle growth (Schoenfeld et al., 2019)
• Muscle growth increases with volume, and each extra set adds less than the one before (Pelland et al., 2026)
• Muscle growth does not require taking sets to failure (Refalo et al., 2023)

The studies tested the principles; the program itself has not been tested in this form.