Progressive overload
Muscles grow when they have to do more than they are used to. In practice that means: over weeks and months you manage more repetitions with the same weight, or the same repetitions with more weight. Without a training log you can hardly tell whether this is happening.
A proven scheme is double progression. You set a repetition range, for example 8 to 12. When you reach the top of the range in all sets, you raise the weight and work your way up again. That way every session is clearly planned, without complicated percentage calculations.
Volume: how many sets
Count hard sets per muscle and week, meaning sets that get close to muscular failure. Warm-up sets do not count. In the meta-analysis by Schoenfeld, Ogborn and Krieger (2017), more weekly sets went with more muscle gain, with the biggest gains from about ten sets per muscle and week.
It does not follow that more is always better. A sensible start is about ten hard sets per muscle and week. If your performance rises and you recover well, you can increase individual muscles; if it stalls and you sleep badly, less is often more. The training volume calculator counts your sets per muscle.
Intensity and proximity to failure
For building muscle, the range of useful weights is wide. When comparing light and heavy loads, Schoenfeld and colleagues (2017) found similar muscle gain when the sets went close to failure; for maximal strength, heavy loads were superior.
What matters, then, is how close to failure you go. The RIR scale (repetitions in reserve), linked to the RPE scale by Zourdos and colleagues (2016), makes this measurable: RIR 2 means two clean repetitions would still have been possible. Most working sets sensibly sit at about 1 to 3 RIR, and for isolation exercises going to failure is fine now and then.
Training plan and frequency
A meta-analysis by Schoenfeld, Ogborn and Krieger (2016) found that training each muscle twice per week produced more gain than once per week. In practice, this also spreads the sets out and makes each session shorter.
Which split fits depends mostly on your week:
- Full body on three days: little time, each muscle three times per week
- Upper and lower body on four days: a good middle ground for most people
- Push, pull, legs on six days: lots of time, lots of volume that can be spread across sessions
Exercise selection
Compound lifts such as squat, deadlift, bench press, row and pull-up train many muscles at once and are easy to progress. Isolation exercises add to them in a targeted way for muscles that get too little from the main lifts, such as side delts, calves or biceps.
Choose exercises you can perform cleanly, with a full range of motion and without pain, and stay with them for a few months. Only then can you see whether you are getting stronger. If you try new exercises every week, you lose the comparison and with it the most important signal of progress.
Measuring strength: estimating your 1RM
You do not have to test your one-repetition maximum (1RM) to plan with percentages. Formulas like those by Epley (1985) and Brzycki (1993) estimate it from a set of several repetitions. They are most accurate with few repetitions; with high-rep sets they deviate more.
The 1RM calculator shows the estimate along with a percentage table, and the plate calculator shows which plates to load for a target weight.
Recovery
Muscles grow between sessions. Enough sleep, enough energy and enough protein are therefore part of training. If performance drops over several sessions, a lighter week with fewer sets and less weight (a deload) often helps. Persistent pain is not a training stimulus: have it checked by a doctor.