Quick Summary
The foot care step most marathoners skip is getting their feet, shoes, and running pattern checked before race week. Most race-day foot problems, such as blisters, black toenails and heel or arch pain, have causes you can look at in training: friction, moisture, tight or worn shoes and repeated load without recovery. A podiatry assessment looks at your hips, knees, ankles and feet, your standing and gait pattern, and your footwear. The earlier you do it, the more time there is to act on what it finds.
What is the one foot care step to take before a marathon?
Have your feet and your gait assessed before race week, while there is still time to change something. Our biomechanical gait analysis is the scientific evaluation of your walking or running pattern, used to identify abnormalities and assess the biomechanics of your lower limbs. It draws on visual and video analysis, 3D motion tracking, and treadmill analysis.
It works because it looks at the cause, not the symptom. If your shoes wear unevenly, you have had blisters or black toenails before, or you have pain that goes beyond normal muscle fatigue, those are all good reasons to have your feet assessed. Running a December race? A gap of three to four weeks leaves room to change shoes gradually, add insoles if they are prescribed, and adjust training.
What are the most common foot problems for marathoners?
The usual suspects are blisters, black toenails, heel pain, arch pain, and stress fractures, and most come from repeated load, friction, or poorly fitting shoes.
| Problem | What drives it | Where to read more |
|---|---|---|
| Blisters | Excessive friction, pressure or moisture on one area of skin | Blisters |
| Black toenails | Blood collecting under the nail after trauma or pressure | Bruised nails |
| Heel pain (plantar fasciitis) | Overuse, with flat or high-arched feet and unsuitable footwear as risk factors [2] | Heel pain |
| Arch pain | Often linked to foot type and support | Flat feet |
| Stress fracture | Repetitive stress on the bone without enough recovery time | Stress fractures |
These can sideline you from training as well as from race day, so catching them early matters.
How do you prevent and treat blisters?
Reduce friction and moisture before the race, and never burst a blister yourself. HealthHub advises well-fitted footwear with thick-padded, soft socks that absorb moisture well, protecting friction-prone areas with dressings, pads or cushions, and using insoles where needed to reduce pressure points [1]. Our blisters guide explains why blisters form and what aftercare to follow.
If one forms, cover it with a sterile, non-stick dressing, keep the area clean and dry, and use a hydrocolloid dressing to cushion it [1]. HealthHub is clear that you should never burst or puncture a blister yourself without a healthcare professional's help or instructions [1]. Our podiatrists can drain or deroof a painful blister using sterilised instruments.
See a doctor if it has not improved within 5 days, or sooner if you notice warmth, swelling, redness, worsening pain or pus [1].
What causes black toenails, and what should you do?
A black toenail is blood collecting under the nail after trauma or pressure, often from shoes that press on the toes over a long distance. Our bruised nails page lists black, blue or purple spots under the nail as the sign, and says to seek professional advice for severe pain, swelling, nail detachment, or persistent discolouration with no obvious cause.
Discolouration with no injury behind it can point to something more serious, so do not assume it is damage from running.
To lower the risk, check how your toes sit in your race shoes, trim nails straight across, and keep new shoes for short outings until they feel comfortable [1].
What are the warning signs of a stress fracture?
Pain that gets worse with activity, eases with rest, and returns when you run again deserves a proper check. Our stress fracture guide describes a sharp or dull aching pain that worsens with activity, pain that improves with rest but returns when you resume movement, tenderness on pressing a specific spot, and mild swelling. Seek help for persistent or localised pain, swelling or bruising, or if you cannot walk or run without discomfort. Do not wait for race day to find out.
What should you do about your feet in the weeks before a race?
Change as little as possible, and test what you change.
- New shoes: wear new footwear for short periods until they feel comfortable [1]. A new pair worn for the first time on race day is an avoidable mistake.
- Fit and wear: check where your current shoes wear and whether your toes have room. Uneven wear is a reason to book an assessment.
- Socks: choose soft, padded socks that absorb moisture well [1].
- Hotspots: note any spot that rubs on long runs and protect it with a dressing or pad.
- Daily check: look at your feet each day for redness, swelling or blisters.
For shoe choice more generally, see our guide to choosing shoes for your feet and our article on running gait analysis.
Are custom insoles worth it for long-distance running?
They can be, depending on your feet, and the way to find out is an assessment rather than a guess. Our customised insoles are podiatrist-prescribed, take 2 to 3 weeks to make, and carry a one-year warranty on materials and craftsmanship. That turnaround is one more reason to have an assessment weeks before a race rather than the week of it. Flat feet, high arches and recurring injuries are the usual reasons they are considered.
Is foot pain normal after a long run?
Some tiredness is expected; pain that is sharp, localised or does not settle is worth checking. If you are unsure which side of that line you are on, our article on foot ache after running walks through common causes.
What should you do after the finish line?
Look after your feet, rest, and watch for anything that does not settle.
- Check both feet for blisters and keep any that form clean, dry, and covered.
- If a toenail has darkened or lifted, avoid running on it and see a podiatrist if it is painful, swollen or detaching.
- Give your body time to recover before resuming hard training.
- If heel, arch or bone pain persists, book an assessment. Shockwave therapy is one option our physiotherapists and podiatrists may consider for musculoskeletal and soft tissue conditions, after an assessment of suitability.
Run the Race, Not the Recovery
Marathon training is hard enough. Most foot problems that end a race have causes you can find in training, so find them while there is still time to do something about them.
Booking Your Podiatry Assessment in Singapore?
Our podiatrists can assess your feet, gait and footwear before your next race. Book an appointment, or send a photo of a blister or nail to Ask Emma on Telegram for free advice from our podiatrists.
References
- HealthHub, Blisters (reviewed 8 January 2026).
https://www.healthhub.sg/health-conditions/blisters - HealthHub, Plantar Fasciitis (reviewed 30 June 2021).
https://www.healthhub.sg/health-conditions/plantar-fasciitis
Ready to feel better?
Book a consultation with our podiatry team to get an assessment tailored to you.
Frequently Asked Questions
It is worth it if you have had foot injuries, blisters or black toenails before, if your shoes wear unevenly, or if you have pain beyond normal muscle fatigue.
Several weeks before the race is better than the week of it, because changes to shoes or insoles need time. Custom insoles take 2 to 3 weeks to make.
HealthHub says never to burst or puncture a blister on your own [1]. Protect it with a dressing, or see a podiatrist if it is painful.
It is the evaluation of your walking or running pattern to identify abnormalities, using visual and video analysis, 3D motion tracking, and treadmill analysis.
Every one of our 11 clinics across Singapore offers both physiotherapy and podiatry. See locations.
