A Living Document ... Ongoing Updates
Back of the Pack - Increase your Chances
by Ulli Kamm
Jan. 8, 2010
Race Selection, "Easy 100 Milers" - Motivation, Preparedness - Weather - RaceaSchedule - DropaBags - Food, Drink, Stomach - Caps, Painkillers, etc. - Pacer - WildaAnimals - Recovery - DNF - Crew - Aging - AtaNight - What_to_Carry - Water_Crossings - Race_Preparation - During_the_Race - Health - Organizers - Useful_Links - Summary
Race Selection, "Easy" 100 Milers
Entry fee for 100 milers is between $0 and $300+. You can also pay $120(!) for a 50k. Think about if you want a belt buckle, "technical jacket", shirt etc.
There is no such thing as an easy 100 miler. But some are less difficult than others
When judging the difficulty of an ultra, for me it more or less comes down to the relationship between total climb and cut-off time. It's e.g. easier 7,200 ft climb in 30 hours ("Leanhorse 100") than 21,600 ft in 33 hours ("Angeles Crest 100"). Footing, altitude etc. also impact speed and effort required, but not so much. For me "Angeles Crest 100" was the most challenging to 100% walk, followed by "Leadville 100". Of course I don't know all races in detail ...
For someone who has a lot of endurance but no so much speed, some 100 milers can be easier than 50 milers with a tougher climb/cut-off ratio
Do the races YOU want to do, not the ones others say you should do
"Hope for the best, be prepared for the worst" - "Never give up, just keep going"
Heard a few minutes before the start of ďAngeles Crest 100Ē: ďAll year long I was excited, I was looking forward to the race. Now I want to go homeĒ
you think you can't go any further, you are only half-way to the point
after which you may do serious damage to your body (applies to healthy,
after which you may do serious damage to your body (applies to healthy, trained walkers/runners)
Mind over body - in a war with an enemy chasing you, you can walk till you die, as you have a very strong motivation. The same may apply to some walkers/runners without an enemy as a motivation. It is extremely difficult for you, as well as for doctors, to decide the actual health status of a walker/runner - some people look good till it's too late, some look bad after a few hours already but are doing fine actually
As very long distances are done more by your mind than by your body, you have to keep the mind busy. That begins with being motivated (different for everybody), having to pay attention (e.g. course specific), music (walkman), short term goals (aid stations), specific food you are looking forward to, etc.
If you like what you are doing, you are getting some strength from internally or from the nature (especially in the mountains)
In some way it's a dangerous sport. Some people get addicted, do long ultras too often and burn out fast, respectively get injuries
"If my stomach ..., if my blisters ..., if the weather ..., if my knee ..." - We hear such excuses all the time. Consider that in many 50 milers and in all longer races there will always be at least one "if". Be prepared
whatís waiting for you: Study maps, course profile, photos, reports, etc.
till you see the course already in your head
To avoid being disappointed early in the race already, set yourself realistic intermediate and overall goals
start for a race when you see a realistic chance of at least 50% to finish within the
animals, listen to birds and to the noises in the forest at night. Check how
the weather develops. Talk to others or just walk quietly together
under race conditions: Rain and mud, in the dark, steep climbs, rough
trails. Come race
day, you know that not very much can surprise you
People who have spent time hiking in the mountains are better at being prepared for a wide variety of circumstances without carrying excessive weight
Get used to be (nearly) last, maybe from start to finish, and always just a few minutes ahead of cutoffs at aid stations. As long as you are within your schedule, it doesnít matter. Walk/run your own race
A 24 hour race is a good preparation (and self-test) for going through a night without sleep, for being on your feet a long time, for testing food, dress, etc.
For a walker it is helpful to practice for speed (racewalking) on shorter distances. Then it's easier for body and mind walking more slowly in longer events
You don't want to do your regular training anymore? Take off the pressure, without really reducing your overall exercise. I never "train" ... but get a lot of exercise. Here are some things I do (unsorted):
Do long "fast-hikes" alone or with friends where it's scenic: forests, swamps, mountains. Set food places as intermediate goals ("Cafe to Cafe") ... kind of aid stations
Walk to the train station in the morning and back in the evening (25 min. each way)
Walk to a Starbucks a few miles away ... if I do it under a time I give myself, I'm "allowed" to eat a scone etc.
"Walk in the park" with family (I don't have a dog, but you may have one) etc.
Take in my office the stairs up 10 floors (in total ~25 floors a day)
At noon I want to get my eyes off the computer and do a fast 30 min. walk in the neighborhood
Snow-shoveling and digging in the yard ... for upper body
Swimming once a week. Breast stroke is great for the sideways movement of knees, which you need on rough trails or x-country
Every race is training for another one
Don't worry so much about walking speed. With lots of pushing a little bit while walking it comes automatically. And really high speed is not necessary to finish a 100 miler within the cutoff
No heart rate monitor and similar "machines" (calorie counter, etc.)
There are many more things we can do to stay in shape. Be creative, do things that are fun!!!
Weather (just some aspects covered)
Be prepared. Don't just believe in what weather is average for race-day. In Colorado e.g. one year there were end of May 8 inches of snow on the ground, and another year, at the same time, it was 104 degrees .
the weather forecast. There shouldnít be any surprises. One year in
ďBoulder 100Ē we had 20 hours (all night) heavy rain, very strong wind,
3 lightning storms nearby and just 36 degrees. When that started, I asked a
girl in running shorts and t-shirt if she has nothing warm to dress. ďThe
weather forecast wasnít too bad, wasnít it?Ē she replied. The forecast
had been even worse Ö
Walmart has in the camping department plastic rain ponchos for $1. They weigh 1.6 oz and are also good against wind. They keep you dry much better than nearly all jackets
A good idea is also a garbage with 3 holes for arms and head
I walked a few times in 100 milers or 24 hour races 20-30 miles with an umbrella. Why not?
Take one of these "Emergency Blankets" with you. They weigh 1.4 oz. You can wrap them around your upper body under your shirt. And in case you have nothing else, use a newspaper for that
A good ultra light down vest doesn't weigh more than 3-4 oz. Put it in a ziploc type plastic bag
When it's cold, the wind chill factor can have significant impact, and may become dangerous in case you are not prepared, especially when the body is already exhausted. Think about warm underwear, a thick down vest/jacket, etc.. I remember a few races when I was wearing 2 pair of thick gloves, 2 winter hats, 3 pants, face covered, ... Wind chill chart: http://www.nws.noaa.gov/om/windchill/
San Juan Solstice 2009, a runner's comment: "I got caught on the Continental Divide between mile 22 and 31 when the snow hit and I wasn't dressed appropriately"
I may not even have the lightest equipment, but here is the weight of a few items:
Windbreaker 3 oz, wind-pants 1.8 oz, hat 0.7 oz., gloves 1 oz, plastic rain poncho (also good against wind) 1.6 oz, emergency blanket (around your body under your shirt) 1.4 oz > total of just 9.5 oz !
When you know that you may encounter hard snowfields, think about bringing MICROspikes, "running crampons", etc.
Make sure to learn how to stop when falling on a steep snowfield
That's the only really "bad weather" I'm worried about. Count the seconds between lightning and thunder: 5 seconds mean the lightning strike was 1 mile away. Usually lightning isn't really close more than 15-30 minutes. Don't pick the tallest tree as a shelter.
Think about not pushing too hard during the hottest time of the day, and then make up for lost time at night. Always cover your head and probably neck as well. Soak hat and shirt with water. Consider also sun lotion. When your forehead is not really salty anymore, it's time for some salty food and something to drink (not water in this situation)
Make sure you don't loose a shoe in sucking mud
Consider that a lot of mud has an impact on your speed
There is no problem with getting really dirty ... shower, washing machine
Think about washing your shoes. I lost a pair of new trail shoes because there was something in the mud that hardened the shoe material
Make yourself a realistic schedule. E.g. if a 100 miler has a 30 hour cutoff, plan for a finish in 29:30 hours
Consider that usually the 1st half of a race is done faster than the 2nd half, if the course difficulty is about equal. Plan for about 55% of the distance in the first half of the time. E.g. in a 100 miler with a 30 hour cutoff, that's 55 miles in the 1st 15 hours. In a 50 miler with a 16 hour cutoff, it's ~27.5 miles in 8 hours.
At night on bad trails (roots, rocks, overgrown, steep climbs), going is more slowly. Steps are shorter, more careful. Things on the ground create dancing shadows with your headlamp/flashlight
races give you the option to send drop bags to one or more aid stations. When
using this offer, there are a few things to consider.
drop bag may not reach the aid station (road blocked, etc.) > Carry
minimum equipment with you (1 AAA flashlight, a $1 plastic rain poncho, Ö)
Drop bags may get lost (e.g. falling off pick-up truck) > No valuable contents
bags may get wet and muddy > Have everything in plastic bags
drop bag should be of solid material. Not just a simple plastic bag
races (e.g. Western States) have limits for the size of drop bags. Check the
may be raining hard when you get your drop bag, and no place to hide > If
you want to change, maybe pick
up something and carry it with you (little pack) till the rain stops
itís an out-and-back course, make sure there is no chaos in your drop bag.
That also applies to loop courses where you may have a bigger bag, a tent,
or even your car available several times
sure your name, bib #, and the aid station where you want your drop bag is
readable (twice on each bag) > Good is using a permanent marker on silver
drop bags, as long as you donít have a crew helping you, takes time >
Especially when there isnít perfect weather or at night, I rather carry a
tiny backpack with me (~2 pounds). Then Iím more independent and faster
through aid stations
goes into a drop back:
Check the weather forecast, but consider that it might be wrong
Consider what time of the day you will access the drop bag. Think about maybe being a couple hours ahead or behind your schedule. E.g. itís getting dark in the forest and your drop bag is still 4 miles away Ö
Dress, plastic rain poncho, gloves, hat, stuff to fix your feet, bars and gels, flashlight and spare batteries, toilet paper in plastic bag (paper towels are stronger and more absorbent), empty plastic bags to put in wet and dirty clothes when changing
95% of DNF are mental. Blisters, a bad stomach, etc. should stop you only in very extreme cases
extreme physical stress and being exhausted, the body can do well only 1
activity at a time: Digest food or exercise
are several phases of being exhausted:
Body tired, muscle pain
Difficulty to eat and keep food down
Not able to talk in a way others can understand
Pain in your head (not a headache) from brain cells ďpoppingĒ (I only had that once in 43 years of ultras; 2 photos: I aged 20 years in 3 hours)
more in the first half of a race. Then you donít need so much in the 2nd
sometimes eat 1/8 of a bagel at a time. Force yourself to eat at least a bit
now and then. Chew it carefully
For many runners chicken soup is excellent for settling the stomach and that little extra energy
the time it takes till the body gets the value/strength from what you eat. E.g.
For white bread it takes ~1 hour, for whole grain bread itís 4-5 hours
also mental: If there is something you really want to eat during a race, eat
it (consider quantity). Your mind often superimposes ďbiological lawsĒ
Check now and then on your forehead, when sweating, if itís still salty.
If not, take action. Salt tablets are not good for kidneys; too
concentrated. I eat instead Miso, broth or soup, potatoes with a bit of salt.
You can also try "Real Salt" http://www.realsalt.com/
or "Morton's Lite Salt" http://www.mortonsalt.com/products/foodsalts/Lite_Salt.htm.
Miso and/or salt are easy to carry
Before you start eating soup or drinking something, make sure it's not too hot
Check out which food has a lot of potassium (e.g. oranges)
Lots of calories and easy to digest: Bananas, avocados
Interesting article about drinking too much: http://www.defeatdiabetes.org/Articles/exercise2050421.htm
stomach is like a bucket with holes in it. You fill drinks into it, which
take time to leave the stomach, getting through these holes. The thicker the
drinks, the longer that takes. So if you drink a lot of stuff with sugar etc.
in it, the bucket may flow over, which means you throw up. Thatís why I
drink pure water between other things.
Heed, etc.: It impacts kidneys. I donít drink more than in total 1 cup
during a 100 miler; and I mix it with 80% water. When these drinks were
new, I tested how much is beneficial for me. When drinking more I found that my
leg muscles hardened
Beer: If you have a crew or can put it in a drop bag, do it. It tastes great
and has calories
In a 100 miler I usually have 2-3 times a 12 oz can. Be aware that the positive impact (blood sugar, caffeine) helps you
for ~1:15 hour (when exhausted itís less).
Especially when the body is really tired already, coffee just tries to take
(performance) from the body, but doesnít give anything. Coke gives
something to the body (fluid, sugar); and it has ~1/6 of caffeine per same
amount of fluid
My main drink is 20% grapefruit juice mixed with 80% water
Drinking only plain water over a longer period of time dehydrates! You start
peeing more and more often, at the end every 5 minutes
or bottle: The last 2 years I see more and more runners going back to
bottles. Reasons: You always know how much fluids you have left, easier to
clean, easier to refill, doesnít freeze as fast in winter, nothing on your
Caps, Painkillers, etc.
Succeed- etc. Caps
I tried it once. Didnít have any positive impact. Donít just believe ads. Test yourself; maybe it works for you
itís really hot, I take 1 tablet each, maybe twice during a 100 miler
Shivering when being cold (often uncontrollable) is often related to a sodium/magnesium deficiency. It usually helps, in case I don't have magnesium tablets with me, if I walk as fast as I (still) can to stop shivering
Pain & Painkillers
There is pain on the outside of the body, like blisters, chafing etc.. Although it may slow you down and it may be really severe, it usually is not serious, as it will heal in a matter of weeks again. More serious is pain inside the body. Things like stomach pain etc. will disappear in most cases without problems - during the race after eating and/or drinking the right things (which may be difficult to decide what is right). Pain of kidneys and other "interior parts" have to be taken very serious
Muscles - in most cases it is normal to have pain. Usually minerals (magnesium, potassium), a salty broth, or even a Coke (disadvantage: after ~1:15 hour your blood sugar is down again), or just slowing down a bit for a while might help. Of course when going more than 50 miles the pain will usually never completely disappear
Tendons - usually overuse, wrong shoe form (good insoles sometimes help). To be treated seriously and need enough time to heal, otherwise the end of an "ultra career" will be soon
Bones - Once a bone in my leg shifted during a 24 hour race and cut into a nerve ... really painful. It happened once and never again. No idea why it happened
Hurting kidneys and liver, at higher altitude even more
Tylenol is easier on kidneys than Ibuprofen and Advil
, although it's a painkiller as well ...
Risk of not feeling warning pain in case a serious problem develops
If you canít handle pain, donít do these races
I take maybe 1 Tylenol per year, when Iím with a dozen blisters 5 miles from the finish and wouldnít be able to meet the cutoff otherwise
To have a pacer works for many people. I tried it twice in 100 milers. It was wonderful to walk with a friend. I just see a risk, that ...
It distracts me, especially when talking, from pushing as hard as I can. So I slow down somewhat. And as in many races I'm fighting for minutes to meet cutoffs, I often can't afford to slow down
Especially in the 2nd half of a 100 miler I frequently listen to my body to discover problems early and think about what to do. Now when talking ...
Several miles before an aid station I start thinking about what I need to do there. That helps me to get through aid stations as quickly as possible. Alone I'm more focused
Especially in trail races there is a peaceful beauty in walking alone through a quiet night ... if under full moon or even in the rain
I met a mountain lion after 53 miles of a 100 miler, slowly crossing the trail ~40 yards in front of me
At the same race, one year later in the middle of the night, I had a close encounter with a lama
35 miles into a 100 miler I found a big snake laying on the narrow trail. As I was really in a hurry to meet the next cut-off, I jumped it ... something you should never do!
Carl Meltzer had to fight with a moose at a 100 miler
I know 2 races where a runner was hit by an elk and needed medical attention
Several ultras in Montana, in areas where there are grizzlies, ask to take bear spray with you. E.g. "Devils Backbone 50 Mile": "Bear spray recommended". At "Swan Crest 100": "The Swan Range is home to a healthy population of grizzly bears; so if you have any bear phobias, this is something to consider."
If you are worried, maybe take at least a dog spray with you
my 40s I could walk 100 k one
weekend and 100 miles in under 24 hours the next. Did it twice ... Risky,
weekend and 100 miles in under 24 hours the next. Did it twice ... Risky, not advisable!
Now being in my 60s, I need at least 8 weeks to recover from a 100 miler, to be able to do the same again
You can do these races more often, but you risk
Not having fun anymore
Not so much your legs, but your head will say "not already again"
Don't try to get your very best (at your limit) in all events. Otherwise after a few years you don't want to do ultras anymore. As long as the cut-off time allows ... I joined a wedding party, went to restaurants on the course with Traudl (my wife) for a nice dinner, sat down and had beer or wine ... That's why I still like ultras after more than 4 decades
Correct food & drink during and after an event has a great influence on recovery
Pain is temporary, quitting is forever
A few years back at the "Leadville 100", at the Fish Hatchery aid station 24 miles before the finish, a runner told his wife/crew that he can't go any further, and that she should drive him back to Leadville. She immediately locked the car doors and drove away. Now he had to keep going ... he finished the race
Miracles happen ... recovery from seemingly hopeless situations. But we need a strong mind to make them happen
Stomach problems etc. are in most cases just an excuse
Usually we hit mental limits (willpower not strong enough anymore) to keep us going and pain limits (feet looking like "mashed potatoes") before we hit physical limits. 95% of all participants dropping out of a race do so because of a "mental limit" - of course there are usually problems with blisters, stomach, etc.. But these are things you can go on with if you are motivated and dedicated enough - and taking the risk of a long recovery period
Never DNF, as long as you did not miss a cut-off or are seriously injured
As long as you are within cut-offs, don't make a decision to drop immediately when you come into an aid station
Most walkers/runners who DNF regret it shortly afterwards
Reduce the risk of a DNF
Take on tough challenges, but on the other side be realistic in your choice of races
Be prepared, know in detail what's waiting for you
"Bad excuses" for DNF (which I heard)
I didn't want to get anaerobic
I wanted to save myself for the next race
As long as after a DNF I can look into the mirror and can honestly say "I did the very best I could under given circumstances. I could not have been a few minutes faster or could not have gone a few hundred yards further", it's ok
Don't depend on a crew. A road may be blocked and your crew can't get to an aid station
Having an experienced crew usually makes you a bit faster. They bring food while you are changing socks, they clean up the mess when you are gone, etc.
For your crew it's many hours of waiting followed by a few minutes of chaos
Make a list for your crew for everything you may need at each aid station
Your crew needs to be fully ready when you come in as you might be in great hurry to meet the cutoff
Your crew should know you well and think about some "goodies" for you (e.g. a cold non-alcoholic beer when it's hot)
A crew should be friendly, encouraging and confident. A walker/runner may be stressed and can't show how very thankful he/she really is
Always say "thank you" to your crew when leaving an aid station (and of course to the aid station volunteers as well)
After the race say "thank you" to your crew with e.g. a little present, an invitation to a nice restaurant, etc.
Getting older we lose more of the fast-twitch fibers that allow us to make quick, powerful movements, than of the the slow-twitch ones that provide endurance
Adjust your challenges, but keep having challenges. Don't loose your love of the sport!
See performance chart for 100 milers, plus a table for various other distances
Women's performance in ultras, for age 50-70, is about the same of man who are 6-10 years older (see chart)
Getting older, most walkers/runners could still finish ultras, but "are tired of" training hard, especially in the mountains
Risk of injuries in training and in races increases significantly
Recovery after events takes much longer, which makes it more difficult to keep training, to stay fit.
It's tricky: You think you have the same speed as some years ago, as the frequency of your steps is the same. But your steps are shorter ...
Having fun shifts somewhat from having it during the event to after the event. The older you are, the tougher it gets to finish an ultra, but the more rewarding it is to still meet the cut-off time
Being in my 60s I am still competitive ... I'm competing against cut-off times
Very important is to train many hours for going at night. Check out how to best handle things like: vision, headlamp/flashlight, sleep deprivation, loneliness, rough trails, cold, rain, water crossings, ...
If fighting to meet cutoffs: No sleep breaks; maybe sit somewhere max. 5-10 min. with closed eyes
If you wear glasses or contacts, bring for the night your strongest
Headlamps, flashlights: A flashlight gives you more flexibility with looking around and it's closer to the ground. But it keeps one hand busy. On more technical courses, where you may need your hands now and then, it's advisable to have both. Check out what works best for you
A very intense light cuts you off from the "outside world" and over time is strenuous for the eyes. Best is to have a light where you can switch levels
Have at least 2 light sources. Being together with another runner, I once experienced up in the rocks at 13,000 ft. (at "Hardrock 100") that all 4 of our flashlights didn't work anymore (broken, wet, etc.). Maybe even have a 3rd one, a tiny little one with 1 AAA battery
I always carry a 1 AAA flashlight with me from the start. What if you can't make it to your drop bag before it gets dark? Or if your drop bag was lost?
Sleep deprivation: Some people can walk extremely long without sleep and without having serious problems. You can train for going without sleep for one or even several nights
On many courses there will be lots of noises around you: Animals moving through the forest, birds flying around, water running somewhere, wind in the trees, rain drops on the leaves, ... Lightning storms are impressive at night. - Learn and then enjoy. It's a beautiful world of which most people are not aware of
That really depends on lots of things
Course and aid stations, crews and drop bags, climate and weather, altitude, time of the year, personal preferences (e.g. ipod), etc., etc.
Drop-bag(s) may be lost
Crew may not be able to reach an aid station
Weather can be different than forecasted
You may be later than your schedule
Here is what I carry
Always with me (in pouch)
My schedule, pen (to take notes about actual times)
Small sun hat; also good against rain
Toilet paper in plastic bag (paper towels are stronger and more absorbent)
Charcoal tablets (stomach)
Money in plastic (buy something, taxi back)
Feet fixing stuff (duct tape, band aid, cream)
Cream against chafing
Depending on course
1 or 2 bottles (in extreme cases 3)
In addition at night or at high altitude
A little backpack (contents total 2-4 pounds)
As mentioned under "Weather": Windbreaker 3 oz, wind-pants 1.8 oz, hat 0.7 oz., gloves 1 oz, plastic rain poncho (also good against wind) 1.6 oz, emergency blanket (around your body under your shirt) 1.4 oz > total of just 9.5 oz!
Energy bar or other food
Enough to dress to avoid hypothermia
2 flashlights and some spare batteries
You know how to swim, don't you? :-)
Consider that it's sometimes more risky, and may take longer, trying to get over slippery and moving rocks and logs, than just going through the water
Deep water: Just holding hands usually doesn't help much. Rather face another runner and both put their hand's on the other's shoulders. In case you are alone, use 1 or 2 sticks, also to find out how deep the water is
I never take off my shoes. You never know what it is you may step on .. and that may be the end of the race for you
Some people get blisters more easily with wet feet, others get less blisters. Test yourself ...
Especially when it is hot, getting wet feet, which usually means cooling them down, reduces their size and they fit more easily in shoes again
Goretex shoes and trail running are in my opinion contradictions anyway. And while your feet after a water crossing usually "press" water out of other shoes fast, in Goretex shoes that will take a while
I had river crossings where in the middle of the night not just I completely undressed (except shoes) to keep things dry
See also under "Motivation, Preparedness"
Drinking lots of cold stuff during a long race when the body is weak anyway, may result in stomach/digestion problems. To avoid that, I take before the race 8-10 charcoal tablets. Buy the 100% natural ones; they are pure "coal powder". And if during a race you should get problems nevertheless, take a few more. I always carry them with me
For many of us it's important to never sit on a cold surface before or during an event ... or we may start chafing soon. And if you need to sit down and really have nothing to put under your butt, sit on your hand
Before an ultra event, many runners/walkers use cream (running stores have it) for various body parts to avoid chafing; e.g. upper arms, upper legs, etc.
I always use duct tape before the start to cover my heels and little toes. The problem is to find a tape that sticks even on some cream, stays on the foot all the time, and is easy to take off again. I use "Leukoplast" (German product)
Dress (just a few aspects)
Be aware that when you are very tired you feel much colder
Wind-jacket (2 oz), wind-pants (1 oz). Wind pants with full zip are best: Faster, when feet muddy, when you are tired and/or in a hurry
If you dress like an onion it's easier to adjust
Very important are well cushioned and wide enough shoes. To extend shoe life, when most of the cushioning is gone, I put a 2nd insole under the original one. I cut off the toe box part of the insole to keep enough room for the forefoot. You get insoles for this purpose e.g. at Walgreens or Rite Aid for ~$4
Insole: To reduce the risk of blisters make sure that with your hand you can barely feel where the insole ends and the back of the shoe starts. In case there is a "bump", that very likely results in blisters
Gaiters are great to avoid sand and other stuff in your shoes (which may cause blisters)
Don't forget a sun hat; and when the sun is really hot, also something to cover your neck
With socks it's worth experimenting, because some feel similar when buying them, but react differently on your feet. A high % of blisters is caused by socks
Watch for them especially on intersections
If you have a pacer, don't fully trust him/her ... watch for markers yourself
At night, in fog or snow, markers may be difficult to see
Rain may wash away chalk etc.
Sometimes non-participants take markers down or even put them in the wrong direction. As long as I am not on a well-known course I always have a map with me and make sure I know where I am
See under "Race Schedule"
Every body reacts differently. Talk to your doctor, Google about it. Here are just a few aspects.
Coffee, Coke, Energy Drinks, ...
Some seeds, pollen, oil, mushrooms, ...
May lead to not recognizing things around you anymore. Stop immediately, lay down if possible and exercise deep breathing for a while. Usually it takes a couple of minutes or so till things are ok again, but only start going again if you are sure things are really back to normal
What helps me not to get knee problems is:
Grind organic millet at home. I take 1 table spoon full every day before breakfast for now ~30 years already
Strengthening muscles and tendons around the knee gives strong support for the knee itself
Frequently climbing mountains, and always in heavy hiking boots (5 pounds)
Switching between asphalt, concrete, dirt trails, horse trails, mud and swamps ...
Doing sports which use the knees somewhat differently. E.g. swimming breast stroke is good for strengthening the sideways movements of the lower leg, and with it the knee
Many participants of ultras contemplate about how these events affect the body. But it impacts every body in a different way. Here are some rules that apply to most runners/walkers:
Give the body time to rest
Do other sports as well ("cross-training")
Don't take every event serious, which means don't always go to your limit
Walking is less stressful on your knees, especially on the downhills
Extreme distances are always dangerous. Learn about yourself, learn from others. Most times when you are feeling bad, you will feel better again after a while - but during a race the bad "valleys" are getting deeper every time, the highs are getting lower and shorter
As an organizer you are always responsible and may go to jail if something happens, independent of whatever waiver participants sign (at least in the US and Europe)
If you participate yourself: Take a cell phone with you when you go these long distances - you may have to call an ambulance
http://www.ultramarathonrunning.com/training/index.html#help (very comprehensive!)
Just learn from one event for the next what's good for you
Challenge yourself, but make sure not to overdo it and to have enough fun to be able to keep going for many years
When a problem exists give it time to heal. Maybe do other sports for a while
You have to learn about ultras by doing these events again and again. How do you feel this time compared to last time, why... , etc.