You’ve started running again after a few weeks off, or you’ve added two sets of squats to your usual session. The next morning, walking down the stairs immediately reminds you of yesterday's workout. It’s classic, and everyone goes through it.
Muscle soreness is not a sign of injury; it is simply a normal response of your body to an unusual effort. To regain comfort and maintain mobility, a few simple actions are enough, provided you know how your muscles work.
What is muscle soreness?
Muscle soreness is a muscle sensitivity that appears after exercise, usually with a time delay. This is what we call DOMS (Delayed Onset Muscle Soreness).
This time delay makes it easy to distinguish from the burning sensation that occurs during exercise, on the last repetitions of an activity.
Why it is different from lactic acid
We still often hear about lactic acid to explain these pains, but the mechanism is different.
The real role of lactic acid (lactate): during intense exertion, when oxygen supply becomes limited, the body quickly uses its sugar reserves. This reaction produces lactate. It is this, combined with local acidity, that creates the burning sensation during the session and forces you to take a break. However, the body recycles or eliminates this lactate very quickly, usually in less than an hour after the effort ends. The next day, it has disappeared from the body.
What really happens with muscle soreness: the phenomenon is primarily mechanical. A heavier or unusual effort creates tiny lesions in the muscle fibers. In response, the body triggers a slight inflammation to repair these fibers and make them more resistant. It is this reconstruction phase, with a slight local edema, that makes the muscle sensitive to the touch and stiff when stretched 24 to 48 hours later.
The burn during the session is therefore linked to the energy system at that moment, whereas the muscle soreness the next day corresponds to the muscle's repair work.
Why muscle soreness appears
In practice, three situations encourage its appearance:
Novelty: discovering a discipline, a new exercise, or a new movement. The muscle fibers are not yet used to this trajectory and take on more tension.
Progressing too quickly: loading too heavy all of a sudden, lengthening a run drastically, or speeding up the pace without a transition.
Eccentric work: this is the phase where the muscle brakes the load while stretching. This is the case during the descent of a squat, landing from a jump, or trail running downhill. This is precisely why downhill trail runs often leave more of a mark the next day than uphill runs.
How long does it last?
The discomfort generally follows a fairly predictable progression:
- 12 to 24 hours: the muscles begin to stiffen.
- 24 to 48 hours: sensitivity is at its peak.
- 72 hours: the stiffness eases, and movements become fluid again.
- 5 to 7 days: the muscle has finished its repair and returns to its normal state.
Note: if the pain persists beyond a week, if it is limited to a very specific point, or if it occurred suddenly during the effort with a sensation of tearing, it is better to seek the advice of a healthcare professional (doctor or physiotherapist).
How to relieve muscle soreness: incorporating cold into your daily routine
The idea is not to block muscle regeneration, but to reduce stiffness to maintain daily ease.
1. Cold, both before and after
Cold is not just an emergency measure after an impact. It is a maintenance reflex that has its place on both sides of the workout.
Before exercise, applying it to the area you are about to stress activates the tissues and prepares for movement. Many athletes incorporate it into their warm-up routine, just like joint mobility exercises.
After exercise, it soothes the feeling of heat in the muscle and provides comfort to a still-sensitive area. The mechanism is a game of contrast: the cold temporarily reduces local sensitivity and constricts the vessels (vasoconstriction), then rewarming causes a reflex vasodilation that stimulates local circulation.
Over time, consistency is what makes the difference. A short application, repeated after each session, helps keep muscles available and allows for chaining workouts with less accumulated discomfort. This is actually the most common feedback from users: it’s not an isolated application that changes things, but the habit.
A useful detail: what we are talking about here is a localized and short application on a targeted muscle group. This is very different from a fifteen-minute full-body ice bath, which follows a different logic and is more for elite-level performance.
Several options exist for applying cold:
- Cold bath: widely used by elite athletes, but not very accessible and difficult to organize at home.
- Ice pack: useful in a pinch, but it quickly loses its temperature, takes up space, and does not allow for precise action.
- Ice roller: pleasant for massage, but tends to warm up quickly.
- Portable cryotherapy roll-on: a practical alternative to easily target a muscle group.
This is the principle behind the Niuksport portable cryotherapy roll-on: its thermal core made of phase change material (PCM), placed in the freezer, powers a stainless steel ball and maintains cold from the first to the last application. Cold, massage, and serum are combined in a single gesture — before the effort to prepare the area, after to regain comfort. Its refrigerated cap allows you to carry it in a gym bag and use it directly at the end of the session.
Cold or hot: how to choose?
Heat relaxes and feels good, but it dilates blood vessels — on an already sensitive and slightly engorged muscle, it can accentuate this feeling of heaviness.
Cold is more versatile: it can be used before exercise to activate, after to soothe, and remains suitable during the 24 to 48 hours when discomfort is strongest.
| When to use | What it provides | |
|---|---|---|
| Cold | Before exercise, after the session, and on sore days | Activates the area, soothes the sensation of heat, provides comfort |
| Hot | On a stiff muscle without particular discomfort, or away from exercise | Relaxes, softens |
In practice: cold accompanies training, heat accompanies rest.
2. Moving gently (active recovery)
Remaining completely immobile often tends to lock up the joints. A twenty-minute walk, some cycling on flat ground, or a few laps of swimming at a leisurely pace help stimulate circulation. The goal is simply to activate the muscles, without seeking fatigue.
3. Massage while staying moderate
Self-massage helps release tension around the sore area. Whether done with the hands, a roller, or a cool ball, the movement should remain gradual. There is no need to press hard: excessive pressure on already sensitive fibers does not accelerate recovery.
4. Hydration and rest
These are the two simplest foundations: a well-hydrated muscle maintains better elasticity, and it is mainly during sleep phases that the body repairs its tissues. No external tool replaces a good night's rest and regular hydration.
The most frequently affected areas
Thighs and quadriceps: highly stressed after elevation changes in running, jumps, or sets of squats. A leisurely walk on flat ground and applying cold along the length of the muscle help regain normal range of motion.
Calves: sensitive when starting running again or changing shoes. They can be a bit stiff upon waking; a few gentle ankle movements in the morning feel good.
Back: often the culprit after core training or pulling exercises. Be sure to distinguish between general muscle fatigue and a blockage that strictly limits movement, in which case medical advice is useful.
Adductors: affected whenever there are rapid changes of direction (team sports, tennis). This is an area to handle with caution: avoid forceful stretching when it is painful and prioritize gentle cold applications.
How to limit the intensity of muscle soreness?
It is rare to completely avoid muscle soreness when looking to progress, but you can easily moderate its intensity:
Take the time to warm up: a few minutes of gradual activation before adding intensity prepare the muscles for the effort.
Increase loads step by step: changing your distances or weights in a measured way from one week to the next gives the fibers time to adapt.
Plan a cool-down: a few minutes of leisurely walking at the end of the session begins the recovery process.
Adopt a routine before and after exercise: combining cold and light massage before and after the session helps prepare the area and anticipate the stiffness of the next day.
The body adapts very quickly: the same session generally generates much less discomfort the second time than the first.
Well-being and recovery product: it does not replace medical advice.
Frequently asked questions
Can you train with muscle soreness?
Yes, by adapting the content of the session. You can reduce the intensity, work on another muscle group, or do an active recovery session. Complete inactivity tends to maintain the stiffness.
Is muscle soreness a sign of an effective workout?
Not necessarily. It mostly indicates that the muscle has encountered a new or unusual constraint. It is quite possible to make progress without feeling significant muscle soreness the next day.
Should you stretch when you have muscle soreness?
It is better to avoid pronounced stretching on an already sore muscle, so as not to pull on fibers that are in the process of repair. Save more intense stretching for days when you feel no discomfort.
What is the benefit of using cold regularly?
Beyond muscle soreness, a short and regular application of cold — both before and after the session — helps prepare the area for effort and regain comfort afterward. It is the consistency of the gesture that counts, more than the intensity of an isolated application.
When should you consult a doctor?
If the pain occurred suddenly during a movement, if it prevents you from performing daily activities, or if it remains sharp after more than a week of rest.
