Aid station from behind the fence.
Some people do spend time walking but it is difficult to walk 50 miles everyday, which is why 50 miles used to be the daily minimum. If you look closely at what the runner has to do to complete his mileage a clearer picture can be seen. The day is 18 hours long so from that deduct all things that a person has to do to live on the track for 2 months.
Bathroom stops
Depending on the food there can be between 2-5 stops for the bowels plus from 5-10 urine stops.(1 min per hr)
Skin protection procedures.
This includes prevention and treatment of blisters and hotspots. Chafing prevention. Sun protection.(1 min per hr)
Changing
It is often necessary to change clothes or shoes. After the first day when the feet have increased by one or two sizes often the shoes have to be customised. Also the changing weather conditions often require appropriate protection.(1 min per hr)
Food and water
Intake of calories is on an enhanced level – 5-10k per day. Assessing whats available from the table and matching that with the bodies desires/needs,putting food into cups to eat whilst moving still takes time.(2 mins per hr)
Rest
Most runners take short breaks throughout the day from 10-30 minutes broken into varying sizes. This totals a minimum of 70 minutes a day of absolute basics.
Most runners have about 16 hours a day give or take a few minutes.
Every day is different but all of the above have to be factored in for the basic issues. Other things can and do develop; for example, injuries. The course of the 3100 is completely on concrete which is an extremely hard surface to spend one’s day plus the concrete wears the shoes away very quickly which can also lead to stress injuries. Every runner has some physical issue over the duration of the race and shin splints is not uncommon plus a host of repetitive use problems that occasionally arise
So this requires about 3.1 miles an hour to cover 50 a day and 3.8 to cover the 61 to finish in 51 days. This is the basic without having to deal with any extra problems.