5/3/1 Assistance Work: Exercises, Sets and Substitutions

The worked example here is the 5/3/1 Triumvirate, the variant built entirely around its assistance work. All four days are pre-built in Hardy's free 5/3/1 Triumvirate routine.

What 5/3/1 assistance work is for

The main 5/3/1 sets are the strength engine. Assistance work is everything else: extra muscle, balance around the joints, and cover for what four barbell lifts miss. That means the upper back, abs, hamstrings and 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 5/3/1 counts it in total reps at easy weights instead of in percentages of a Training Max.

5/3/1 assistance exercises: push, pull, single-leg or core

In Wendler's later books the rule is simple. Each session, do one push, one pull and one single-leg or core exercise. Aim for 50-100 total reps of each on a normal day, and 25-50 when the rest of the session is already heavy.

How much you do depends on the rest of the session. On Boring But Big days the 5x10 Supplemental Work already costs a lot, so assistance drops to the low end. First Set Last days leave more room. The Triumvirate has no Supplemental Work at all, so its two assistance exercises carry the whole back half of the session.

The Triumvirate pairings, day by day

The Triumvirate caps assistance at two exercises for 5 sets each, roughly 50-75 reps per exercise. Each pair has a job:

• Press day gets a second push and a vertical pull, so shoulders and lats both grow.
• Deadlift day trains the hamstrings, glutes and lower back again at lighter loads, plus direct ab work.
• Bench day adds pressing volume and the 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 exercise except leg curls. They are a deliberate isolation pick, because nothing else in the week bends the knee under load.

How heavy the 5x15 and 5x10 sets should be

There are no prescribed percentages for assistance work. Pick loads by feel and leave a few reps in the tank on every set. If you cannot finish all five sets with about 90 seconds of rest, the weight is too heavy. If the last set does not burn at all, it is too light.

Progress reps first, taking all sets to the top of the range. Then add the smallest available increment and rebuild. For dips and chin-ups, work toward the full rep count across five sets, with bands if needed. Add external load only when the target reps are comfortable.

Substitution rules: swap the exercise, keep the slot

The program does not care which specific exercises you use. It cares that each slot keeps doing its job. Swap within the same category and nothing breaks:

• 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, or any other hip hinge.
• 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 apply. First, swap for equipment, injury history or a glaring weak point, not for novelty. Changing exercises 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 the job of Boring But Big. If you keep wanting more barbell volume, read 5/3/1 Triumvirate vs BBB and switch for a cycle.