Week one hurts in a way you probably expected. Week two often feels surprisingly encouraging. Then something shifts — a tightness that lingers a bit longer than before, a specific tender spot on your shin that was not there last week, or a general sense that your body is not quite matching your enthusiasm.
You are not sure if it is serious, you are not sure if continuing is sensible, and it feels easier to just leave it for now. This post is about that exact window: understanding what is actually happening in your body across the first four weeks, and how to read the signals correctly so that "leaving it for now" does not turn into six months of not running.
Why the first few weeks can feel inconsistent
There is no universal four-week biological script for new runners. People adapt at different rates depending on previous activity, training history, sleep, recovery, age and other individual factors. However, there are some common experiences during the first few weeks that are useful to understand.
Week 1: Getting used to a new demand. Your heart rate may climb faster than expected and your legs can feel heavy. Delayed-onset muscle soreness — DOMS — commonly follows unfamiliar exercise and is usually most noticeable during the following 24–72 hours. It can involve muscle tenderness, stiffness and temporarily reduced function. On its own, DOMS does not necessarily indicate a clinically significant injury.
Week 2: The early adaptation window. Some people begin to notice that running feels a little easier and that initial muscle soreness is less pronounced. Early improvements can reflect cardiorespiratory and neuromuscular adaptation, while tendons and other connective tissues may adapt over longer timescales. Feeling fitter therefore does not necessarily mean every tissue involved in running has adapted at the same rate.
Week 3 and beyond: The enthusiasm checkpoint. You feel fitter, and the temptation is to run longer, run faster, or add an extra day. Some studies have reported associations between changes in training load and running-related injury, but the overall evidence remains inconsistent. There is no established biological ‘week-three danger zone.’ When running begins to feel easier, resist the urge to change distance, frequency, and pace all in the same week.
Week 4: Establishing sustainable patterns. For many, a consistent routine has formed and tissues are adapting well. For others, quiet, cumulative overload may have been building. Many overuse-related running problems develop gradually rather than following one obvious incident. Repeated loading that exceeds a runner’s current capacity may contribute, although training load is only one factor among many.
4 practical steps you can try now
1. Learn the difference between DOMS and a warning signal
DOMS usually involves generalised muscle soreness and stiffness rather than one sharply localised point. It is commonly most noticeable within 24–72 hours of unfamiliar exercise and generally settles over the following days. Gentle movement may feel comfortable, but DOMS does not require a particular treatment to resolve.
By contrast, pain that is sharply localised, worsening during running, changing how you move, or becoming progressively more noticeable from one session to the next deserves closer attention.
2. Keep a simple training note
You do not need complicated tracking technology. A short note recording session duration, perceived effort and any symptoms gives you useful context over time. Research has not identified one injury-proof progression formula, but keeping a simple record can help you notice changes in training alongside changes in how your body feels.
3. Be cautious about changing multiple variables at once
When running begins to feel easier, a conservative approach is to avoid increasing distance, speed and frequency all at once. Changing one variable at a time also makes it easier to understand how your body responds. This is a practical strategy rather than a scientifically established injury-prevention rule.
4. Remember that recovery is where adaptation happens
In the early weeks, leaving at least one recovery day between running sessions is a sensible approach. The NHS Couch to 5K programme follows this structure. If soreness or heaviness from a previous run has not settled, waiting an extra day is entirely reasonable. Training provides the stimulus; recovery gives your body time to respond to it. An easy walk on a non-running day can provide light activity with substantially less impact than running.
When to get a clinical assessment
Most new runners do not need a clinical assessment simply because they have started running. An assessment may be useful when pain is persistent, becoming more localised, repeatedly returning, changing how you run, or when a previous injury is making you uncertain about how to progress. Specific signals worth acting on include:
- Pain is becoming more localised, more intense or more persistent from one run to the next.
- Pain is changing the way you walk or run.
- A specific area of the shin, knee, foot or heel remains unusually tender.
- Symptoms repeatedly return when you resume running after reducing your training.
- A previous injury is making it difficult to judge how quickly you should progress.
Where do osteopathy and movement assessment fit?
At Momentum Body Clinic, an assessment can consider your symptoms, recent training load, previous injuries, joint movement, strength and relevant movement tasks. The aim is not to find one hidden mechanical fault, but to identify factors that may be relevant to your individual presentation.
Depending on the assessment, management may include advice about modifying running temporarily, exercise, movement guidance, osteopathic treatment or massage. If another healthcare professional or further investigation would be more appropriate, this should also be discussed. Our clinic at the Southwark Park Athletics Track Gym on Hawkstone Road (SE16) provides an active, practical environment for running assessments. Consultations are also available at our Telegraph Hill clinic on Kitto Road (SE14).
Running pain or something that doesn’t feel right?
If pain is persisting, repeatedly returning, or making you uncertain whether to continue, an initial osteopathy consultation can help assess the presentation and discuss appropriate next steps.
Prefer to ask a question first? Contact Momentum Body Clinic .
- Part 1: "I'm Not a Runner" — How to start running safely in South East London
- Part 2: Your first 4 weeks of running: what to expect and what’s normal (you are here)
- Part 3: 3 common running problems in new runners — and the factors that may contribute
- Part 4: Running after 35: what changes and what stays trainable
- Part 5: Your first 5K in South East London — A practical 8-week run-walk plan
Research and guidance
- Cheung K, Hume P, Maxwell L. Delayed onset muscle soreness: treatment strategies and performance factors. Sports Med. 2003;33(2):145–164. PMID: 12617692.
- Kjaer M, Langberg H, Heinemeier K, et al. From mechanical loading to collagen synthesis, structural changes and function in human tendon. Scand J Med Sci Sports. 2009;19(4):500–510. PMID: 19706001.
- Buist I, Bredeweg SW, van Mechelen W, et al. No effect of a graded training program on the number of running-related injuries in novice runners: a randomized controlled trial. Am J Sports Med. 2008;36(1):33–39. PMID: 17940147.
- Nielsen RO, Buist I, Sørensen H, et al. Training errors and running related injuries: a systematic review. Int J Sports Phys Ther. 2012;7(1):58–75. PMID: 22389869.
- Fredette A, Roy J-S, Perreault K, et al. The association between running injuries and training parameters: a systematic review. J Athl Train. 2022;57(7):650–671. PMID: 34478518.
This article provides general information and is not a diagnosis or personal medical prescription. Last clinically reviewed: 28 September 2026.