Progressive Overload on Machines: What to Do When the Next Pin Is Too Heavy

Progressive overload on machines works exactly like it does with a barbell (see our guide to exercise selection and biomechanics): you do slightly more over time. The catch is that a weight stack only lets you add load in big steps, so when the next pin is too heavy, you progress with reps first, then with small add-on weights, a slower tempo or an extra set.

That is the whole idea. The rest of this guide is the practical detail. If you have ever stared at a lat pulldown stack thinking “I can do pin 8 for 10 reps but pin 9 feels impossible”, this is for you.

Why does progressive overload on machines feel harder?

Three things make machines feel stickier than a barbell, and none of them mean machines are worse for muscle.

The jumps are big. A barbell lets you add 1 kg with two small plates. A weight stack might jump 5 kg per pin, or 10 kg on older machines. For a big muscle group that is fine. For biceps, triceps and side delts it is a wall.

The stack number is not the force you feel. Pulleys, cables, guide rods and cams all lose some force to friction, and the mechanical advantage changes through the range. The exact amount varies by machine and brand, and I cannot give you a reliable figure. What matters is that 40 kg on one machine is not the same effort as 40 kg on another.

Every gym has different gear. A Hammer Strength plate-loaded press, a Life Fitness pin-loaded press and a cheap local gym version all load you differently, even if each says “40”.

Do machines build muscle as well as free weights?

Largely yes, and that matters because it means you are not giving anything up by leaning on machines.

A 2023 systematic review and meta-analysis pooled 13 studies and 1,016 adults who trained with free weights or machines for at least 6 weeks. Hypertrophy did not differ between the two (SMD -0.055, a negligible gap), and neither did dynamic or isometric strength in direct comparison (Haugen et al., 2023). Strength did show some specificity: free-weight strength rose more with free-weight training. Only five of the studies measured hypertrophy, so treat the muscle-size conclusion as good rather than final.

A small 2025 randomized within-subject trial agrees. Eight untrained young women trained one leg with lunges and the other with an inclined leg press for 9 weeks. Both legs grew, with no difference between them (Amanuma et al., 2025). Eight untrained women is a tiny sample, so I would lean on the meta-analysis more.

If you want the broader comparison, see our guide to free weights vs cables vs machines.

Step 1: Use double progression before you touch the pin

Double progression is the lowest-effort fix. You choose a rep range, keep the load fixed, and only move up once every set reaches the top. We cover the full model in double progression explained, but here is how it plays out on a machine.

Say you are doing a seated row at pin 8, target 8-12 reps for 3 sets.

• Session 1: 8, 8, 7 reps
• Session 2: 9, 9, 8
• Session 3: 11, 10, 9
• Session 4: 12, 12, 12. Go up.

Why does this work? Research on loading suggests you have more room than the old rule of thumb allows. A 2021 review argued that muscular adaptations can be obtained, and in some cases optimised, across a wide spectrum of loading zones, rather than only in a narrow “hypertrophy rep range” (Schoenfeld et al., 2021). A 2017 meta-analysis of 21 studies, with all sets taken to momentary failure, found muscle hypertrophy was similar between low-load (60% of 1RM or less) and high-load training, while max strength favoured heavy loads (Schoenfeld et al., 2017).

In practice, that means a machine set of 12 and a set of 8 can both grow muscle, so climbing from 8 to 12 reps is real progress, not a consolation prize. One caution: those studies mostly compared sets taken to or near failure, so reps only count if the effort is honest.

Step 2: Microloading machines with add-on weights

When the next pin is more than you can handle, microloading fills the gap. Many gyms keep small magnetic plates or clip-on add-ons designed to sit on top of the stack. Typical sizes run from about 0.5 to 2.5 kg, but check what your gym actually has. We go deeper on the upper-body version in microloading with fractional plates.

A few practical points:

• Place the magnet on the top plate being lifted, directly above the pin, so it lifts with the stack and does not rattle against the rods.
• Check it does not touch the frame. A magnet that catches adds friction and noise, which defeats the purpose.
• Add it to your log as a separate line, for example “pin 8 + 2.5 kg”.
• If your gym has none, ask. Small add-on weights are inexpensive, and some gyms will buy a set if members request it.

Home gyms are the same story. Small fractional plates cost little and last for years, and our plate calculator helps you work out loads when you mix sizes.

Step 3: Tempo and range of motion as small steps

If you have no magnets, you can still make the same pin harder in a controlled way. Slowing the lowering phase by a second or two increases the time the muscle works per rep, and you can record it like any other variable.

I would treat this as a tiebreaker, not a main strategy. We cover the evidence in our review of tempo and repetition duration, and the practical message is that you do not need to slow every rep to grow. Use it when you have nothing smaller to add, keep it identical from session to session, and write it down (“3 sec down”). If you change tempo and pin in the same week, you cannot tell which one helped.

Range of motion works the same way: a deeper, controlled stretch on the same pin is harder. Just do not count a sloppy shortened range as progress. The point is to do the same job better, not to cheat the number.

Step 4: Add a set

If reps, magnets and tempo are all exhausted, add a little volume. A 2017 meta-regression of 15 studies found that each additional weekly set per muscle was associated with a small increase in growth, about 0.37% greater gain, within a graded dose-response relationship (Schoenfeld et al., 2017). That is an average across studies, not a promise for you, and more sets cost more recovery.

One trap: switching to single-arm or single-leg work does not shrink the pin jump. You use roughly half the stack on one limb, so the same 5 kg step becomes a bigger percentage, not a smaller one. If the jumps feel strange through the range, our note on selectorized machine cam profiles explains why stacks load you unevenly.

How hard should machine sets be?

Machines are a good place to push close to failure because the path is guided and the weight will not trap you. The evidence on exactly how close is mixed, so here are both sides.

A 2023 meta-analysis of 15 studies found a trivial advantage for training to set failure over non-failure (effect size 0.19), and no advantage for momentary muscular failure specifically (effect size 0.12, confidence interval crossing zero) (Refalo et al., 2023). A 2024 exploratory meta-regression using estimated reps in reserve found the opposite direction for hypertrophy: muscle growth increased as sets finished closer to failure, while strength gains were similar across a wide range (Robinson et al., 2024).

Why might they differ? The first compared categories (failure versus not), the second treated proximity as a continuous scale and relied on estimated RIR, which the authors themselves call exploratory. A cautious takeaway: stop most sets roughly 1-3 reps short, and take the last set of an exercise to or near failure if the machine feels safe. You can estimate this with our RIR and RPE calculator.

How to track machine progress without fooling yourself

Pin numbers only mean something inside one machine. A good log line has five parts:

1. Machine name and brand (or “gym B chest press”)
2. Seat, pad or lever setting
3. Pin number plus any add-on
4. Reps for each set
5. Reps in reserve and tempo

The seat setting matters more than people think, because moving it changes the lever arm and the feel of the same pin. Our training logbook guide shows a simple layout. If you want to compare how plate-loaded and pin-loaded designs differ for chest work, read plate-loaded vs pin-loaded chest machines.

A simple weekly routine for stuck machine lifts

If you want a plan to paste into your notes, try this for a lift that has stalled for two or three weeks:

• Week 1: Same pin, aim to beat last session by one rep on any set.
• Week 2: Keep chasing reps. If you have a magnet, add the smallest one once all sets hit the top.
• Week 3: Hold the pin and slow the lowering by about 2 seconds, noting it down.
• Week 4: If you are still stuck and recovering well, add one set. If you are tired, rest instead.

If a lift keeps stalling for more than a month, look at sleep, food and weekly volume before blaming the machine. Our free workout plans give a structure you can drop these lifts into.

A note on pain: if a joint hurts as the weight rises, back off and see a physio or doctor rather than pushing through. Progress that costs you an injury is not progress.

The bottom line

Progressive overload on machines is not a downgrade from free weights. Muscle growth looks similar in the research, the stack jumps are just bigger. Add reps first, then use small add-on weights, a consistent slower tempo or one extra set, and log your pin, your seat and your reps so you are always comparing like with like. Small repeatable wins add up faster than one heroic jump you cannot hold.