Why Am I Sore After a Workout? DOMS Explained

If your legs are stiff two days after a session you were fine during, you're in familiar company. Feeling sore after exercise your body isn't used to — a first gym session in months, a longer run, a heavier set, a weekend of footy — is a common experience. One of the most common forms of post-workout soreness is delayed onset muscle soreness, usually shortened to DOMS.

The short answer to "why am I sore after a workout?": you most likely asked your muscles to do something unfamiliar or harder than usual, and the soreness is part of how your body responds to that. It typically shows up after the session rather than during it, and for most people it eases on its own.

That said, not every ache is ordinary muscle soreness. Sharp pain, significant swelling, an area you can't use normally, or pain that followed an obvious injury are different signals, and this article can't assess any of them. We don't diagnose anything here — where something concerns you, an appropriate health professional is the right call.

What Is DOMS?

Delayed onset muscle soreness is the muscle tenderness and stiffness that develops in the hours and days after exercise rather than during it. It tends to affect the muscles you actually worked, often feels worse when you first move after sitting still, and usually eases as you warm up.

The pattern most people notice is that it follows exercise the body isn't accustomed to: starting something new, coming back after a break, adding weight or distance, or changing the type of training. Movements with a lot of lengthening under load — downhill running, lowering heavy weights slowly, deep lunges and squats — are commonly associated with more soreness than steady, familiar work like easy cycling or swimming.

On mechanisms, careful language matters. Current explanations centre on the muscle and connective tissue responding to unaccustomed mechanical load, with an inflammatory-type response and changes in how sensitive the area feels. The full picture isn't settled, and you don't need to know it to make sensible decisions about training.

Why Do Muscles Get Sore After Exercise?

Training works by giving your body a stress it then adapts to. When the stress is familiar, the response is usually modest — you finish the session, feel worked, and get on with your day. When the stress is unfamiliar in type, intensity or amount, the response tends to be more noticeable, and soreness is part of what you feel.

This is why the same session can feel wildly different at different times. Legs that squat every week handle a set of squats far more comfortably than legs meeting them again after three months off. It's also why soreness generally fades as you repeat something: your body gets used to the demand.

It's worth not overstating any of this. Soreness is a sensation, not a measurement of how much you improved, how hard you worked, or how much muscle you built. Plenty of genuinely productive training leaves very little soreness behind.

When Does DOMS Usually Start?

The defining feature is the delay. Rather than peaking during the session, soreness typically appears some hours afterwards, is often more obvious the next morning, and commonly feels worst a day or two after the exercise before starting to settle.

Individual experiences vary a lot. Some people notice it the same evening; others wake up fine and feel it properly on the second day. How sore you get, and when, depends on what you did, how unfamiliar it was, and simply on you. Treat the general pattern as something to observe in yourself rather than a schedule your body has agreed to.

How Long Does DOMS Last?

Ordinary post-exercise soreness usually improves over a few days as things settle, but there's no fixed timeframe and we're not going to promise one. What matters more than the number is the direction: soreness that is gradually easing behaves differently from pain that keeps getting worse.

Things that tend to influence how you feel and for how long:

• How unfamiliar the exercise was — new movements and returning after a break commonly leave more soreness.
• Training intensity — heavier, faster or more maximal efforts usually feel different afterwards than easy work.
• Training volume — more sets, more kilometres or a longer session adds up.
• Individual differences — age, training history, sleep, stress and general health all sit in the background.
• Recovery between sessions — how much time, food, fluid and sleep you got before doing something demanding again.

If soreness is dragging on well beyond what you'd expect, or it's not improving at all, that's a reason to get advice rather than to keep experimenting.

DOMS vs Injury: What's the Difference?

This is the distinction most worth understanding, and it's also where general information stops being enough. The lists below are a way of thinking about what you're feeling — not a diagnostic checklist, and not a substitute for assessment.

DOMS may feel like

• General muscle tenderness or stiffness rather than one sharp point of pain
• Soreness in the muscles you recently trained, often on both sides
• Discomfort that appeared after the session rather than during it
• Something that eases as you move and warm up, and settles over following days

Possible warning signs

• Sudden or sharp pain, particularly if it came on during the session
• Significant swelling or bruising
• Being unable to use the area normally, or a joint that feels unstable
• Pain that followed an obvious injury such as a fall, collision or awkward landing
• Symptoms that are worsening rather than easing, or anything else that concerns you

None of that tells you what's happening in your body — only that some experiences deserve a proper look. If you're worried, or your symptoms sit in that second list, speak with your GP, a physiotherapist or your local health service rather than training through it and hoping.

What Can You Do When You're Sore After a Workout?

The honest answer is that ordinary soreness largely resolves on its own, and the useful things are unglamorous. None of the following is promised to remove DOMS — they're sensible general recovery habits that help you feel and function better while it passes.

Easy movement

Plenty of people find gentle movement more comfortable than sitting still — a walk, an easy ride, some light mobility. Keep it comfortable; if it turns into another session, it isn't recovery. We go through this properly in active recovery: what it is and when to use it.

Rest

Rest is a legitimate option, not a failure of discipline. Giving worked muscles more time before the next demanding session is often the most effective adjustment available.

Sleep

Sleep is where most of your recovery quietly happens, and it's the first thing to protect during a heavy training block or a stretch of long shifts.

Hydration

Replacing the fluids you lost during a session is basic housekeeping — not a soreness cure, but worth doing well.

Normal, balanced nutrition

Eating enough, including adequate protein and carbohydrate across the day, supports the ordinary business of training and adapting. There's no need for anything exotic.

Adjusting the next session

If you're properly sore, moving a hard session, reducing it, or training something else is a reasonable decision rather than a setback.

For the hours immediately after training, how to recover after a workout walks through the routine step by step, and muscle recovery after exercise looks more closely at what the evidence supports.

Should You Exercise When You Have DOMS?

Sometimes yes, sometimes no — and that isn't a dodge. It depends on how sore you actually are, what you were planning to train, how much recovery you've had, and your own circumstances. We can't write your program from here.

Mild, general soreness that eases as you warm up is something many people train around comfortably, often by keeping the session easier than planned or working different muscle groups. That's very different from grinding through significant discomfort with a heavy session because it was on the calendar — that tends to compromise the quality of the session and your recovery at the same time.

Choosing easy movement instead is usually the better trade when you're unsure — we work through that decision in should you train when you're sore?, and our guide to active recovery covers what those easier days can look like in practice. If pain is sharp, worsening or came on suddenly, the sensible move isn't an easier session — it's advice.

Can You Prevent DOMS Completely?

Probably not, and it isn't a realistic goal. Any time you introduce unfamiliar exercise — a new sport, a new lift, your first hill session — some soreness is a fair possibility, and that's not evidence you did something wrong.

What generally makes life more comfortable is building up gradually: introducing new movements at modest volume, increasing load or distance in steps rather than leaps, and giving yourself recovery between demanding sessions. That's sound training practice, though it's not a guarantee against soreness.

We won't point you at a supplement or product to prevent DOMS. The evidence for preventing soreness is far weaker than the marketing around it, and progression, sleep and food remain the parts worth your attention.

Common DOMS Myths

Myth: soreness means you had a good workout

Soreness mostly tells you something was unfamiliar. Well-designed training that you're used to can leave you barely sore at all while still being effective, and chasing soreness as a scoreboard tends to lead to erratic, punishing sessions rather than consistent ones.

Myth: DOMS is just lactic acid sitting in your muscles

This one persists, but the timing alone undermines it: lactate produced during exercise clears within roughly the first hour or so afterwards, while DOMS typically arrives well after that and peaks a day or two later. Delayed soreness is associated with the response to unaccustomed loading, not with lactic acid pooling in your legs overnight — see the sources below.

Myth: you should always push through soreness

Sometimes training through mild soreness is fine. Other times more recovery is the productive choice, and occasionally what you're feeling isn't ordinary soreness at all. "Always push through" removes the judgement that actually keeps people training consistently.

A Simple Post-Workout Soreness Checklist

• Consider whether the soreness followed unfamiliar exercise
• Keep normal hydration and nutrition habits
• Prioritise sleep
• Choose easy movement if it feels comfortable
• Adjust training if your body needs more recovery
• Pay attention to sharp, severe or worsening pain
• Seek appropriate advice if something concerns you

This checklist is general information to prompt sensible decisions, not medical advice, and it can't assess your symptoms.

When Should You Get Advice?

Most post-exercise soreness settles without any intervention. It's worth speaking with a health professional where there's significant or worsening pain, major swelling or bruising, a loss of normal function in the area, symptoms that followed an obvious injury, unusual symptoms such as feeling generally unwell or unusually dark urine, or muscle pain that seems out of proportion to what you did.

We can't diagnose anything, and we're not trying to. Your GP, a physiotherapist or your local health service can assess what's actually going on — an article can't.

The Bottom Line

Soreness after unfamiliar or demanding exercise is a common response, and DOMS is the delayed version of it — the stiffness that shows up after the session rather than during it. It's a different thing from pain that signals an injury, and knowing the difference is more useful than any single recovery trick.

Beyond that, the fundamentals do the heavy lifting: sleep, food, fluids, sensible progression and training decisions that respond to how you actually feel — including whether an easy day or a full rest day suits you better. How often you train sits alongside all of it, and we work through that in how often should you train? More on how that plays out across sport, training and physical work sits in the Recover hub, the Train hub and across all our guides.

Sources & further reading

• Australian Institute of Sport — Recovery (Australian Sports Commission)
• Healthdirect Australia — Muscle pain
• Better Health Channel — Muscle strain (Victorian Government)
• Better Health Channel — Physical activity — it's important
• Healthdirect Australia — Sleep