It's "just a trail horse"
How many times have you heard people refer to it as “just trail riding” or “horse can only do trail riding, no heavy work”. Trail riding itself requires a lot of physical ability from the horse.
First off, the horse needs the strength to be able to carry your weight safely. If the back is not strong, you are going to end up with a sore horse.
Your horse needs cardiovascular fitness. Have you ever gone on a walk or hike carrying a heavy backpack. How out of breath are you, even if it’s just a short walk on flat, well groomed footing?
Speaking of footing, your horse needs to be able to carry itself (and you) over varying terrain. They need to be light in the front end, have excellent proprioception and strong tendons and ligaments. Have you ever rolled your ankle while walking on flat ground? Imagine doing that while carrying someone on your back.
Your horse needs to have a strong core. They are required to maintain forward movement, all while carrying you and negotiating obstacles such as walking over logs or branches, picking their way around roots and rocks, up and down hills, over different terrain.
Your horse needs hind end strength to be able to make it up and down those hills safely
It is never “just trail riding”. It is a sport in itself and your horse needs to be properly conditioned for it, whether you’re doing an endurance ride or a short ride on local trails.
Need some help? Download this trail conditioning plan from Ride Like an Athlete here: https://ridelikeanathlete.com/shop/p/conditioning-plan
The same could be said about saddles. How often have you heard “oh I just need a cheap saddle. All I do is trail ride”. Then they wonder why their horse doesn’t like to go out on the trail. Saddle fit is super important for the trail horse as well. Their body is moving in all different directions trying to make their way over less than perfect terrain. Try a hike in cheap shoes that don’t fit right and see how happy you are and if you enjoy hiking after that!