I tried to research this using search engines and found such a random variety of recommendations. Some were saying to make sure you have your tetanus booster while others were citing a study that shows the antibacterial properties of dirt/clay. It's hard to know who to believe.

How should one treat common mountain bike crash abrasions on their knee?

  • 3
    A must for any cyclist should be an up-to-date tetanus shot as you rightly say, since this is probably the greatest risk in any kind of ground contact. And more so on soil than on tarmac.
    – Carel
    May 30, 2020 at 11:30
  • 1
    Tetanus would be something to have done before you ride. Its a bit late if you've already hit the ground, though there are booster shots they tend to be harsh and less effective if given after the infection.
    – Criggie
    May 30, 2020 at 12:49
  • for nightmare fuel, look up "debridement".
    – tedder42
    Jun 2, 2020 at 20:51

4 Answers 4


Briefly, a quick rinse with clean water, and possibly dressing it, are probably all you need to do on the trail. This assumes a day visit to a typical trail centre or cross country riding near to facilities in a country with a reasonably accessible healthcare system, i.e. most mountain-biking. This was also confirmed by an outdoor first aid course I did recently (these are a very good idea).

You don't know what's in the dirt, so studies discussing antibacterial properties of certain mineral compounds aren't very relevant, even if they're effective against the bacteria that might be an issue, in the wild as opposed to in the lab. As an extreme example, consider coming off into fresh dung on a rock - slippery, unhealthy, but still capable of causing a graze.

Alcohol wipes are now deprecated for wound cleaning; first aid kits now include sterile saline wipes instead, but apart from using a folded corner to flick particles of dirt away, they're not very effective.

Rinsing with your water bottle is about as good as you'll get for cleaning while on the trail. This is a good reason to have plain water in (one of) your bottle(s) - most other drinks would not be such a good idea (similarly, washing muck out of important bike parts). Getting enough flow from a Camelbak isn't so easy, and you need to have plenty of water with you to do this. Some ride leaders I know carry a spare bottle that they don't drink from (instead decant from it), for this, dehydrated novices etc., but in general the wounded person's own bottle should be first choice.

Once the wound is fairly clean it may be a good idea to dress it to keep it that way, but on something like a knee that flexes a lot while riding, this can be more trouble than it's worth. If you're bleeding properly it's still a good idea to cover the wound. Large stretch fabric sticking plasters (band aids) are ideal; in my riding first aid kit I have a selection of these and also bigger dressings. I carry more than most people as I'm used to leading kayaking and road riding. A more thorough clean might be needed when you can, e.g. a shower, or several bottles of water when there's a tap.

After a recent tumble leading to unsightly grazes on my knee and elbow (and that first aid course) my preferred dressing for wounds on moving parts is now the sort with a sterile pad and built in conforming bandage - it doesn't rely on adhesion so is more sweat-proof, and flexes well, while looking rather like a cartoon bandage. Zinc oxide tape is a also good for holding down dressing, if you use plenty.

Keeping your vaccinations up to date (tetanus being the most relevant) is an important general rule, regardless of what you do at the time of the injury.


Simple skin abrasions/grazing:

Symptoms: bleeding, can still walk.

  • Sit the patient down out of the way. Let the blood flow for a short time to help push out embedded debris. Rinse the area with clean water, and apply some cloth and pressure. Ideally raise the injured area above the level of the heart to decrease pressure and let the wound clot. Give the patient liquids, talk calmly. They might appreciate a Gel or some food.
  • After 5 minutes wet the cloth and peel it off. Ideally bleeding will have stopped. Check the bike over, and ride on home when ready.

The rest of this got a bit OTT but left for completeness.


Symptoms: Hurts, but no/minimal bleeding. It is a bruise that hasn't coloured-up yet.

  • Sit and relax the patient. Apply anything you have that is cold or cool like water. If its an ankle, remove the shoe. Get patient to flex the muscle to stop it stiffening up. Head straight home, the injury will swell up. When home, get ice on it immediately.

Broken bone

Symptoms: limbs at wrong angles, can't use limb.

  • Call ambulance. Calm patient, give water, keep them warm, etc. You will need to make a judgement decision if getting the patient out is possible - can they walk with arm in a sling? If a leg then they're not walking or riding, so assign someone in the party to meet the ambulance, who will need a stretcher. If you're well in the backcountry, it might be worth looking to make up some way to carry the patient, though this is not easy.

Joint separation

  • I'm not familiar enough with this one. Probably similar to broken bone - the patient might be able to walk but not ride. [TBC]
  • An injured person may be able to sit on their bike and steer but not pedal, so you can use an inner tube as a towrope. Slow and steady.

Head/neck/spine injury

  • Call the ambulance. Similar to broken bone - you're not walking out. Keep the patient warm and comfortable. Keep them awake too - don't let them fall asleep. Call the ambulance.

If you've gone far enough off-road, an ambulance might not be possible and a helicopter may be required.

If you're out of cell phone coverage, assign a party member to ride to somewhere with coverage and relay details to emergency services. That may be up a hill as the quickest solution.

Have no hesitation in requisitioning help. It is totally OK to flag down others - that 4WD fishing in the distance may be well equipped, or that farmer over the valley may have radios that work where your cellphone doesn't.

My "immediate" responses in event of an accident:

  1. Get it safe - that means getting off the track/road. If the injury is bad enough that moving might be unsafe, then stop oncoming road or trail traffic - send someone with a torch/flashlight if possible.

  2. Identify the injured - if there's more than one down then you have to quickly prioritise. Ignore anyone whose walking around complaining about scratches on their carbon, focus on anyone who is not moving.

  3. Assess the injuries - talk calmly. Evaluate if its grazing and wind knocked out, or something worse. Apply first aid as required.

  4. Identify your resources - how many able bodied people are there, including bystanders and anyone who has stopped to help. Assign a person to each task that needs doing:

    • Sit with each injured person and administer first aid as required.
    • Clear the road of bikes/debris
    • Take some photos for evidence, (like licence plates)
    • Contacting your nation's emergency services line 911, 111, 999, 000, or whichever.

All of this happens really quickly, and that list is a bit stilted and formalised. In reality its a lot more parallelised.

If you think you need it, call for an ambulance sooner than later. They generally take a while to get anywhere. Even having your national emergency service on a phone can be helpful guidance.

If you're riding on your own, well you'll have to do it all yourself. Ideally, don't go too bush alone, or if you do then go prepared. An EPIRB is a reasonable addition to your kit if you're in the backblocks.

  • 1
    +1 but I suggest the immediate list doesn't really capture what happens: "If the injury is bad enough that moving might be unsafe, then stop oncoming road or trail traffic - send someone with a torch/flashlight if possible" is absolutely true, but in practice someone almost always needs to alert approaching traffic. The amount of time it takes to get up after a crash, even without any real injury is more than long enough for there to be a significant risk, especially if multiple riders have gone down in a tangle.
    – Chris H
    May 30, 2020 at 15:58
  • 3
    It'd be worth adding for head/neck/spine injury, protect the spine at all costs — immobilise the head and neck or hold them steady. If you even suspect a spinal injury, the importance of that cannot be overstated - it can mean the difference between a quick discharge from hospital, or months or years spent in hospital and physical therapy, or never being able to walk again.
    – ArtOfCode
    May 30, 2020 at 16:34
  • 2
    Removing shoes for bashed up but not broken feet/ankles is all very well if they don't have to self-extract, but limping on wheels or feet is easier with shoes on
    – Chris H
    Sep 15, 2021 at 14:35

The problem you are having is probably the difference between First Aid and medical treatement. From Wikipedia...

First aid is the first and immediate assistance given to any person suffering from either a minor or serious illness or injury, with care provided to preserve life, prevent the condition from worsening, or to promote recovery

Giving tetanus shots, cleaning wounds and even applying disinfectant/antibacterials is not first aid. Giving pain releif is usualy not first aid, but common. When medical treatement facities are a long way off First Aid takes treatement further - how you treat someone where an Ambulance is called and on the way may be very different to how you treat someone 3 days ride from the nearest road.

How should you treat a MTB abbrasion - Cover with dressing or bandage and then visit a medical center for treatement as soon as practical. Strictly speaking, advice on how to treate a wound is Medical Advice and Off topic for this site. One big problem is every wound is very different and what I call a large complex wound, you may think is trivial. The locatio of teh injury, the envroment where it occured greatly changes the risk factors for infections and disease. If I give advice, I am unlikely to consdier diseases that might occur in a tropical rain forest, and while I might say "if its large, vist a doctor" what I think of as large might be very different to yourself.

Best thing you could do is attend an outdoor, ideally MTB specific, first aid course.


The American Red Cross Wilderness First Aid manual (American Red Cross (2014) "Wilderness and Remote First Aid Reference Guide". Page 98-Abrasions) says that if it is a simple abrasion, even with some dirt, if you treat it within the first 10 minutes, you can cover it with a thick layer of wound gel, cover with a sterile dressing and go.

If it is longer than 10 minutes or you have items (sand, pebbles, etc,) then you should scrub it clean with soap and water, rinse it off, cover with a thin layer of wound gel, and protect with a sterile dressing and bandage.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.