How to actually build muscle in a particular place

Almost everything that decides whether a muscle grows comes down to one number, and it is not the one the internet argues about. Here is what that number is, how to pick exercises that reach the part of a muscle you care about, where a starting weight should come from, and how to progress when there is no weight to add.

The one number that matters

Hard sets, per muscle, per week. Not the split. Not the order of the exercises. Not whether you called it push-pull-legs or upper-lower. Growth rises with weekly sets and flattens somewhere past about twenty for most people, and the same weekly total done over two sessions edges out doing it in one. Everything else in a training programme is detail arranged around that.

Two things hide inside the word "hard". A set counts when it finishes within a couple of reps of the point where another one was not happening. Sets that stop well short of that do very little, which is why a session can feel long and busy and still not have done much — six comfortable sets lose to three uncomfortable ones. And the muscle in question has to be the one working: a set of squats is not a set for your calves because your calves were present.

Rough bands to start from: about ten weekly sets per muscle if you are new, fourteen with a year or two behind you, eighteen or so if you have been at it for years. Below about five, growth is slow; above about twenty, the return per set gets small and the recovery cost does not.

Reps, and the argument that turned out not to matter

Low reps for strength, high reps for tone — this is the most durable piece of gym folklore there is, and the tone half of it is not a thing. Muscle grows across roughly five to thirty reps per set at much the same rate, provided the set finishes close to failure. What changes across that range is how much strength you also gain (more at the low end), how much it hurts (more at the high end) and how safe the exercise is to take near failure.

That last point is what should decide the rep range for a given movement, and it is the reason a sensible plan asks for five to eight on a heavy barbell squat and twelve to twenty on a lateral raise. A set of twenty squats taken to failure is a different kind of risk from a set of twenty lateral raises.

Regions: real, and much smaller than you have been told

A muscle is not one unit, and the differences are measurable:

• Chest. Incline pressing grows the upper pec more than flat pressing does. Both grow the whole muscle.
• Calves. A seated calf raise reaches the soleus properly; a standing one barely touches it, because a bent knee takes the gastrocnemius out of the movement. These two really are different exercises.
• Hamstrings. Hinging movements — Romanian deadlifts, good mornings — and knee-flexion movements — leg curls, Nordic curls — grow different parts. Doing only one leaves part of the muscle behind.
• Triceps. The long head crosses the shoulder, so it only gets a full stretch with the arm overhead. Pushdowns alone under-train the biggest of the three heads.
• Shoulders and biceps. Front, side and rear delts respond to different movements; the biceps' long head prefers the arm behind the body, the short head the arm in front.

What this is not is a way to choose a shape. The effect of emphasising a region is a few per cent of growth over months. Where a muscle attaches to bone — which is what actually decides how it looks on you — does not move, and no exercise makes it move. And nothing you do to a muscle takes fat off the area around it: spot reduction has been tested directly, repeatedly, and it does not happen.

What weight to start with

There are two honest answers and one dishonest one. The dishonest answer is a precise figure from a website that has never seen you lift. The first honest answer is "a weight that makes the last rep of your target range hard" — true, and useless if you have never done the exercise and are standing in front of a rack.

The second honest answer is a bracket. A novice back squat for a set of five sits somewhere near three-quarters of bodyweight on the bar; a dumbbell lateral raise near six per cent of it in each hand. Those ratios move with training age, and they move with the average difference in upper-body strength between the sexes — which is large for pressing, roughly a third, and much smaller for squatting and hinging. Applied to your bodyweight they give a range wide enough to be honest and narrow enough to be useful.

Then the important part: the first set is the measurement. If you were aiming for eight and got fifteen, the guess was light and now you know roughly by how much. If you got four, it was heavy. One set replaces a population average with something about you, and after that the bracket has done its job and can be forgotten.

Progressing: the double progression

The rule that survives contact with real life: pick a rep range, and add reps until you reach the top of it on every set with a rep still in reserve. Then add the smallest increment you can, which will push you back to the bottom of the range, and start again. This works whether the increment is 2.5 kg, 5 lb or the next dumbbell on the rack, and it stops the two common failures — adding weight every session until form collapses, and never adding weight at all.

When there is no weight to add

Bodyweight training builds muscle. Sets still have to finish close to failure, which is the part people miss — twenty easy push-ups are a warm-up, not a set. The genuine difficulty is progression: there is no small plate, so the step up has to come from leverage, and leverage moves in jumps.

Every movement has a ladder. Push-ups run from a wall, through a counter, a step, the knees, the floor, feet elevated, diamond, archer, to a one-arm negative. Squats run from a chair, through a full squat, a split squat, a Bulgarian split squat, to a pistol. Pull-ups run from a dead hang, through scapular pulls, band assistance and slow negatives, to the real thing. When you take a step, expect your reps to drop by a third or more — that drop is the sign it worked, not a sign you have gone backwards.

Two muscles are genuinely awkward without equipment. Hamstrings need something to anchor your feet before a Nordic curl is possible, and the back needs something to hang from or pull against — a bar, or the edge of a sturdy table for inverted rows. If you buy one thing, buy the bar.

What else has to be true

Protein and enough food. Roughly 1.6 to 2.2 grams of protein per kilogram of bodyweight a day — about 0.7 to 1 gram per pound, and not losing weight quickly. Building muscle while losing fat works for beginners and for people returning after a layoff, and gets much harder after that.

Sleep, and time. The work is done in the gym; the building is done afterwards. A reasonable expectation for someone new is a few hundred grams of muscle a month at the start, and less after the first year. Anything promising a visible change in a fortnight is selling something.

Patience with the signal. You cannot see muscle growth week to week, and the mirror is a bad instrument — light and hydration move it more than a month of training does. The honest weekly signal is whether the weight or the reps went up.

Doing it without handing over your training history

The Muscle Building Planner does all of the above in your browser: choose the muscles and the regions, tick what you have to train with, and it picks the exercises that reach them, works out the weekly sets, splits them across your sessions, and gives a starting bracket rounded to a dumbbell or a plate loading that exists — in kilograms or pounds. With nothing ticked it gives the bodyweight ladders instead. Nothing is uploaded and there is no account.

Related: Strength Progress for whether the work is showing up as strength, and Weight Trend & Adaptive Calories for the eating side.