Plans, paces & PBs What normal soreness can feel like
New runners often notice tired calves, thighs or glutes after a session, especially during the first few weeks. A dull muscular ache that appears after exercise and improves over the next couple of days can be part of adapting to a new activity.
That does not mean every ache should be ignored. Use the pattern over time, not bravado, as your guide.
Signs to be more cautious
Sharp pain, pain focused in one small area, swelling, pain that increases as you run, or pain that changes your normal walking or running stride are different from ordinary muscle fatigue.
If that is happening, stop the session rather than trying to run through it.
Should I repeat a week?
If the sessions are leaving you excessively sore each time, repeat the week or reduce the running effort before progressing.
Couch to 5K is not a race through nine boxes. A slower progression that lets your body adapt is more useful than reaching week 9 injured.
When to seek advice
If you have persistent or worsening pain, significant swelling, symptoms that concern you, or you are unsure whether it is safe to continue running, speak to an appropriate healthcare professional.
This guide cannot diagnose an injury; its job is to help beginners distinguish normal training discomfort from signs that deserve more caution.