5/3/1 Triumvirate Assistance Work: The Exercises, the 5x15/5x10 Scheme, and How to Substitute

What assistance work is for in the Triumvirate

The main 5/3/1 sets are the strength engine; the two assistance exercises are everything else - extra muscle, balance around the joints, and coverage for what four barbell lifts miss (upper back, abs, hamstrings, single-limb work). Wendler's framing is blunt: assistance work assists. It never competes with the main lift for effort or session time. That is why the Triumvirate caps it at two movements for 5 sets each, roughly 50-75 reps per exercise, instead of a bodybuilding circuit.

The four days and their pairings

The logic of each pair: press day gets a second push and a vertical pull, so shoulders and lats both grow; deadlift day hits the posterior chain again at lighter loads plus direct ab work; bench day adds pressing volume and the upper-back rowing that keeps shoulders healthy; squat day fills in quads and hamstrings with machine work that will not dig into recovery. Every slot is a compound or large multi-joint movement except leg curls - a deliberate isolation pick because nothing else in the template flexes the knee.

How heavy the 5x15 and 5x10 sets should be

There are no prescribed percentages for assistance - pick loads by feel and leave a few reps in the tank on every set. A good test: if you could not complete all five sets at the chosen weight with about 90 seconds of rest, it is too heavy; if the last set does not burn at all, it is too light. Progress reps first (all sets to the top of the range), then add the smallest available increment and rebuild. For bodyweight slots like dips and chin-ups, work toward the full rep count across five sets, use bands or rest-pause if needed, and add external load only when the target reps are comfortable.

Substitution rules: swap the exercise, keep the slot

The template does not care which specific accessories you use; it cares that each slot keeps doing its job. Swap within the same category and the program is intact:

• Dips: close-grip bench, push-ups, dumbbell overhead press, triceps extensions.
• Chin-ups: pull-ups, lat pulldowns, inverted rows.
• Good mornings: Romanian deadlifts, back raises, reverse hypers - anything hip-hinge and posterior chain.
• Hanging leg raises: ab wheel rollouts, weighted sit-ups, cable crunches.
• Dumbbell bench press: incline dumbbell press, weighted push-ups, machine chest press.
• Dumbbell rows: barbell rows, chest-supported rows, cable rows.
• Leg press: front squats at moderate weight, lunges, Bulgarian split squats, hack squats.
• Leg curls: Nordic curls, glute-ham raises, Romanian deadlifts if nothing else is available.

Two guardrails. First, substitutions should be driven by equipment, injury history or a glaring weak point - not novelty; changing accessories every week makes progressive overload on them impossible to track. Second, keep barbell substitutes honest: swapping leg press for heavy back squats means squatting hard twice in a session, which is BBB's job, not the Triumvirate's. If you keep wanting more barbell volume, run Boring But Big instead of mutating this template into it.