DOMS: why your muscles are sore after a workout

What is DOMS?

DOMS meaning: delayed onset muscle soreness. "Delayed" is the key word. You feel fine when you leave the gym after a hard leg workout, then the next morning stairs feel harder than they should, and the day after that it can be worse.

DOMS is linked to small-scale damage and the repair process in muscle fibres after work they are not used to. The lowering part of a lift (the eccentric phase) causes the most, which is why the first Romanian deadlifts, Bulgarian split squats or walking lunges in a while are known for leaving you sore.

It is not caused by lactic acid. The burn you feel during a hard set is a different thing and is gone within minutes. Lactate is cleared long before DOMS begins.

Typical signs of DOMS

• A dull, tender ache in the muscles you trained, not in the joints
• Stiffness and reduced range of motion, for example struggling to straighten your arms after bicep curls
• It hurts most when you stretch or contract the muscle, and eases once you warm up
• Both sides feel about the same after exercises that train both sides equally

How long does DOMS last?

The timeline is fairly consistent from person to person, although how strong the soreness feels varies a lot:

If the soreness is still strong after a week, or is getting worse instead of better, it is probably not ordinary DOMS. See the section on when to see a doctor below.

Why are my muscles sore after the gym?

The most common reasons for sore muscles after a gym workout:

• You are new to lifting, or back after a break. The first two or three weeks are the sorest.
• You tried a new exercise or a new program, even if you are experienced.
• You did a lot more volume than usual: more sets, more reps, or a longer session, for example after switching to a high volume plan like the Arnold split.
• You trained a muscle in a long, stretched position, as in RDLs, deep lunges or incline curls.

The good news is the repeated bout effect: after one session of a new exercise, the next sessions cause much less soreness. That is why regular lifters who train the same lifts week after week often feel only mild DOMS, even though they are lifting far more.

What helps sore muscles?

Nothing makes DOMS vanish overnight. Time is the main cure. These options are simple, low risk and can make the next few days more comfortable:

Active recovery for sore muscles

Active recovery means gentle exercise that gets blood moving without adding new damage. Good options for DOMS:

• 20 to 40 minutes of walking or easy cycling
• An easy swim
• A light session of the sore muscle group: 2 sets of 15 to 20 reps at a weight that feels easy, no hard sets
• Mobility work through a comfortable range

Keep the effort low: you should be able to hold a conversation. The goal is to feel looser afterwards, not to train.

Should you train with sore muscles?

Usually yes, with a little common sense. Working out with sore muscles is normally fine, and a warm-up often makes mild DOMS disappear for the duration of the session.

• Mild soreness: train as planned. It tends to go once you are warm.
• Moderate soreness: train other muscle groups, or do the planned session with fewer sets and a bit less weight.
• Severe soreness that limits how you move: rest that muscle group or do active recovery instead. Your technique will suffer and the session will not be productive.

A split helps here. With push pull legs or an upper lower split, you can train hard on the days the sore muscles are resting.

Soreness is also not a measure of a good workout. You can build muscle and strength with very little DOMS. A better sign of progress is whether your weights and reps go up over time, which is what progressive overload is about.

How to prevent sore muscles

You cannot avoid DOMS completely, but you can keep it small:

1. Start lighter than you thinkIn the first session of a new exercise or program, do 1 to 2 fewer sets than planned and stop each set with several reps left.
2. Increase volume graduallyAdd sets over a few weeks instead of jumping from 6 to 20 sets for a muscle in one go.
3. Train regularlyTraining the same muscles once or twice a week keeps the repeated bout effect working. Long breaks reset it.
4. Warm upA few lighter sets before the work sets prepare the muscle and joints. It will not prevent DOMS on its own, but it makes the session better.

When soreness is a reason to see a doctor

Ordinary DOMS is uncomfortable but harmless. Seek medical help promptly if you notice any of the following after training:

• Dark urine, brown or the colour of cola or tea
• Extreme swelling, or a muscle that feels very hard and tight
• Pain far out of proportion to the workout, or pain that keeps getting worse after day 3
• Real weakness, for example being unable to lift your arm or stand up from a chair
• Fever, nausea or feeling generally unwell

These can be signs of rhabdomyolysis, a rare but serious condition where muscle breakdown affects the kidneys. It is most often linked to extreme, unaccustomed workouts, heat and dehydration.

Also see a doctor or physiotherapist for pain that does not fit the DOMS pattern: sharp or sudden pain during a set, pain in a joint rather than a muscle, swelling or bruising, or pain on one side only after a two-sided exercise. That is more likely an injury than soreness.

Questions people ask