The guide

How often to train, and how long to rest

How many days a week to train, how long to rest between sets, what a rest day is, and how to pick up again after a week away.

4 min read · Updated 20 October 2026

Two questions come up early: how many days a week should I go, and how long should I rest between sets? (A set is a few lifts of the weight in a row, without a break; more below.) Guidelines and research answer both, and they leave you more room than you might expect.

How many days a week

Health guidelines in the US and the UK agree: do strength training on at least two days a week, and work all the major muscle groups. The NHS, the UK's health service, names them: legs, hips, back, abdomen (your middle), chest, shoulders and arms.

If you haven't been active, US government guidelines say you can begin with one day a week at a light or moderate effort, well short of your hardest, then build up to two. Their phrase for this is "start low and go slow."

Spreading the work across your week

There are two common ways to cover every muscle group:

Whole body each time. Each workout has something for your legs, back, chest, shoulders, arms and middle. Often called full body.
A split. You divide the muscle groups across different days, for example upper body one day and lower body the next.

The American College of Sports Medicine (ACSM) is a US body of sports doctors and exercise scientists. Its 2026 review found that with the same number of sets in a week, training a muscle once a week or more than five times gave similar muscle growth. For strength, training at least twice a week did better, though the edge shrinks when the number of sets is the same.

So pick a pattern that fits your week. For strength, work each muscle at least twice a week if you can: full body does that in two workouts, upper and lower in four.

Rest days

In this guide, a rest day means a day off strength training, or a day off for the muscles you worked last time.

The guidelines above don't say how long to wait before working the same muscles again. Leaving a day between workouts that use the same muscles is a common habit; the ACSM's 2026 finding above suggests it isn't strict. With a split, you can train on back-to-back days, because each day works different muscles.

Rest between sets

Three words first:

Rep, short for repetition: one complete movement of the weight.
Set: a group of reps done without resting. "Three sets of ten" means ten reps, a rest, ten more, a rest, ten more.
Rest: the time between sets.

What the research says:

A review of studies on rest and strength found that for people new to training, 1 to 2 minutes between sets seemed to be enough for the full strength benefit. Experienced lifters seemed to do better with more than 2 minutes. Even rests under a minute still brought solid gains.
The ACSM's 2026 review found that resting under a minute or over a minute made no difference to strength gains.

In plain words: about 1 to 2 minutes is a good place to start, and resting less when you're short on time still works.

Sharing while you rest. On a busy machine, someone may ask to "work in": you take turns, and they do a set while you rest. As a rough guide, one gym chain suggests offering to let someone work in when it's busy and you've rested more than a couple of minutes.

After a week away

Weeks off happen: work, travel, a cold. There's nothing to make up. Doubling up the next week would go against the guidelines' advice to build up gradually. Your next workout is the one to do.

Choose the weight by effort. Pick a weight you can lift for the number of reps your plan asks for, with about 2 or 3 reps left in you. That's the effort the ACSM's 2026 review suggests. Because it's based on effort, it adjusts to the day: if last time's weight feels heavier today, use a little less. That's not a step back.
Your guess may be off by a rep. On average, people have about one more rep in them than they think, whatever their experience. That's normal, and guesses get a little closer in later sets.
If you've been away much longer than a week, it's fine to start again the way the US guidelines suggest for people who haven't been active: one day a week at a light or moderate effort, then build back up to two.
If you were hurt, or you still have symptoms after being ill, check with a doctor before you start again.

The ACSM's 2026 review also found that small amounts of strength training still bring real benefits, and that one set is better than none. A short workout in a busy week still counts.

When to check with a doctor

Check with a doctor before you start if you have a health condition, are pregnant, or haven't exercised in a long time.
Stop if you feel pain, dizziness or chest discomfort. If a symptom is new, see a doctor before you carry on.

In the app

Train Personal asks a few questions, including how you'd like to split your week, and has a plan ready: full body, upper and lower, push pull legs (chest and shoulders one day, back the next, then legs), or one muscle group a day. Rest starts by itself, and your phone tells you when rest is over, even when it's locked. When it's time to add weight, the app tells you and says why, and nothing changes unless you tap it.