Should Exercises Hurt During Rehab? How to Understand Pain Signals

Rehab exercises do not have to hurt to work. Mild, familiar discomfort can sometimes be acceptable during rehabilitation for a long-term musculoskeletal problem, but more pain does not mean more progress. A new or recent injury, an operation and unexplained symptoms may need a more cautious rule.

The useful question is not only, “How much did it hurt?” It is also: What did the sensation feel like? Did it change your movement? Did it settle afterward? How did the area respond later that day and the next morning?

Pain during exercise is not simply good or bad

A 2025 systematic review compared exercise that allowed pain with pain-free exercise in adults with chronic musculoskeletal pain. Across 16 trials, neither approach was clearly better for pain or disability at short-, medium- or long-term follow-up. The evidence was low or very low certainty, but it suggests that pain does not always have to be avoided—and that deliberately provoking pain is not necessary for a better result. 2025 systematic review of painful versus nonpainful exercise

This evidence applies to chronic musculoskeletal pain, not every situation. It should not be used as permission to push through a new traumatic injury, possible fracture, post-operative restriction or unfamiliar neurological symptom.

Four different signals people often call “pain”

What you notice	What it may mean for the session
Muscle effort, warmth or fatigue	Often expected when the target muscles are working; technique should remain controlled
A mild stretch or pressure	May be acceptable if it matches the exercise goal and does not keep increasing
Familiar, tolerable symptoms	May be monitored in some long-term conditions if they remain stable and settle as planned
Sharp, catching, electrical, spreading or rapidly increasing pain	Pause and reassess the exercise rather than forcing the next repetition

These sensations do not diagnose what is happening in the tissue. Even words such as “sharp” do not prove damage by themselves, but a new or escalating symptom is a reason to stop, change the task and decide whether assessment is needed.

A practical response check

Instead of relying on one pain number, check the whole response.

During the exercise

• Is this the same symptom you expected to monitor, or something new?
• Does it remain mild and stable, or rise with every repetition?
• Can you keep the intended technique without holding your breath, guarding or shifting away?
• Does making the exercise easier reduce the symptom?

Some physiotherapy services use a traffic-light guide as a starting point: low pain may be acceptable, moderate pain suggests reducing the load or repetitions, and high pain means stopping. One NHS guide also expects mild exercise-related pain to settle within two hours. These thresholds are examples, not universal rules for every diagnosis or stage of healing. Kingston and Richmond NHS advice after physiotherapy

After the exercise

Notice whether the symptom settles toward its starting level, stays elevated or continues to build. New swelling, loss of movement, limping or difficulty with normal tasks suggests that the dose may have been too high or the exercise needs reassessment. Kingston and Richmond NHS advice after physiotherapy

The next morning

Compare with your usual baseline. If pain, stiffness or function is meaningfully worse, reduce the next dose instead of repeating the same load. You might change the resistance, range, repetitions, sets or frequency. The acceptable next-day response should be agreed around the condition and goal rather than copied from somebody else’s programme.

Is it pain or delayed-onset muscle soreness?

Delayed-onset muscle soreness, or DOMS, usually appears after unfamiliar or demanding exercise rather than at the moment of injury. It often involves broader muscle tenderness and stiffness, with symptoms commonly peaking 48 to 72 hours after the session. Review of delayed-onset muscle soreness

DOMS can happen when returning to strengthening, but it is not the goal of rehabilitation and is not proof that a session was effective. Consider the location and timing: soreness across the muscles trained is different from a sudden joint pain, a new focal pain at the time of exercise, or symptoms that spread with numbness or weakness.

Why the rule can differ by condition

Pain-monitoring rules are often condition-specific. In one randomised trial involving 38 people with Achilles tendinopathy, participants who continued pain-monitored tendon-loading activities during rehabilitation did not have worse outcomes than those who temporarily stopped those activities. That result supports a monitored approach for that study population; it does not create a general permission to exercise through every painful condition. Achilles tendinopathy pain-monitoring trial

A stricter approach may be needed after surgery, with a recent fracture or ligament injury, during an inflammatory flare, or when there are precautions around weight-bearing and range. Follow the plan from the relevant medical or rehabilitation team.

How to make an exercise easier without abandoning rehab

If an exercise produces more symptoms than intended, you can often adjust one variable and retest:

1. Reduce the movement range.
2. Use less resistance or body weight.
3. Perform fewer repetitions or sets.
4. Slow the movement and improve control.
5. Add hand support or choose a more stable position.
6. Increase rest or reduce session frequency.
7. Substitute a different exercise that trains the same goal more comfortably.

The point is to find a repeatable dose, not to win one difficult session. If every variation remains painful or symptoms keep escalating, pause that exercise and seek guidance.

What a physiotherapy assessment may look at

A physiotherapy assessment may compare symptoms before, during and after a movement; check strength, mobility, balance, swelling and movement strategy; and relate the findings to work, sport or daily goals. The plan can then define what response is acceptable, how quickly it should settle and which changes mean the exercise needs review.

This can be especially useful when you are restarting gym training, sport or rehab Pilates after injury, because the same exercise may be appropriate at one load and excessive at another.

When to stop and seek medical care

Stop the exercise and seek urgent medical advice after an injury if pain or swelling is severe or worsening, you cannot bear weight, the area looks deformed, or you have fever or feel unwell. Emergency assessment is appropriate if the body part has changed shape or becomes numb, tingly, blue, grey or cold. NHS sprains and strains guidance

Stop immediately and seek urgent help for chest pain, fainting, severe or unusual breathlessness, or symptoms that feel medically unsafe rather than like a local exercise response. Cambridge University Hospitals exercise safety guidance

Related reading

• What Happens During Your First Physiotherapy Session?
• Sports Injury Rehab in KL: Why Rest Alone Is Usually Not Enough
• Beginner Pilates After Injury: How to Start Safely with Rehab-Focused Guidance
• Home Exercise Programs in Physiotherapy: How to Practise Safely Between Sessions
• Sore After Physiotherapy: What Is Expected and When to Ask for Help

Frequently asked questions

Should every rehab session be pain-free?

Not necessarily, especially with some persistent musculoskeletal conditions. However, pain-free exercise can still be effective, and pain should not be deliberately chased without a condition-specific reason and monitoring plan.

What if the pain disappears after warming up?

That may allow the activity to continue at an appropriate dose, but it is not the only check. Monitor whether symptoms return later, whether movement quality changes and how you feel the next morning.

Is muscle burning during strengthening a warning sign?

A temporary burning or fatigue sensation in the working muscle can be a normal effort signal. Stop and reassess if the sensation is unfamiliar, sharply localised, accompanied by loss of control, or does not ease with rest.

What should I do if I am worse the next day?

Reduce the load, range, repetitions or frequency and return to a level you previously tolerated. If the change is substantial, keeps recurring or affects normal function, ask your physiotherapist or medical professional to reassess the plan.

Sources and clinical references

• 2025 systematic review of painful versus nonpainful exercise
• Kingston and Richmond NHS advice after physiotherapy
• Review of delayed-onset muscle soreness
• Achilles tendinopathy pain-monitoring trial
• NHS sprains and strains guidance
• Cambridge University Hospitals exercise safety guidance

If you are in Kuala Lumpur or Selangor and are unsure whether your exercise response is acceptable, you can WhatsApp Cherrie to ask whether a physiotherapy or rehab Pilates assessment may be suitable.