There were half-a-dozen riders each for the 25km category and the 15km fun ride.
President Shane Dougan said during the long training rides, "you really get to know your horse", and this becomes key during competitive events.
"You've got to read your horse; you've got to know when to back off and when to push - there are a lot of tactics involved."
However, Mr Dougan said that entry level in the sport "is very easy and anybody can have a try".
Riders on Sunday headed west from the Clareville Showgrounds, doing much of their riding on the grass verge of the roadside, but also through farmland thanks to Alistair Smith and David and Bernie Ellison, Mr Dougan said.
Farmland is often muddy at this time of year, but Mr Dougan said there were "beautiful riding conditions this time around".
Preparing a horse for a 40km ride takes about three months, Mr Dougan said - "you slowly build your horse up".
Horses must be well shod and well fed, and vets are on hand at events to ensure their welfare.
Novice horses have a minimum time requirement to prevent them being pushed too hard, but for the more experienced, it is a race.
Distances build up to 120km and even 160km - 100 miles.
Endurance horses are generally Arab or Arab cross.
The CTR part of the club's name stands for Competitive Trail Riding.
Rider Lisa Southon said the surface was "a nice flat track with most of the ride being on the road.
"(There were) lovely grass verges and great flowing track with everyone qualifying through the course - all within the time.
