Traditionally, ranch horses were started at 4/5 year olds and worked hard.
At that age they were mayure, but had spent all those growing years on maturing as a pasture horse, not fit to be a riding horse.
They were considered old and worn out at ten.
Today, many started in two year old programs, are still going strong into their late teens, some made into rodeo performers, at the top competitions into their 20’s.
Like a kid growing up playing with other kids and roaming the streets, not into any sports games activities.
Take a kid growing from vey young in all kinds of sports programs and ss an adult turning pro, is easy.
Muscle memory, work ethic, being a good team player, all those years have taught that kid physically and mentally to be a sport’s ace.
The kid growing up steet wild would have a much harder time as an adult to become any kind of competitive sportman.
Similarly that horse started early has grown into that athletic ace we expect horses to become, mentally and physically and with years of experience.
Injuries? Those can happen at any age and if not started properly.
Several decades of studies now point to horses started properly early do have better physical and mental parameters than those started later.
One meta study of many of those studies was published ininby the government saying just that, horsesvstarted early have less injuries and live longer and healthier into old age than those started older.
On the phone and don’t have the link, but has been posted here before.
Some times, we should not believe what we think, do check around to confirm it, or on this topic learn our old strongly felt ideas manot have been correct.
Proof is all those old horses in all disciplines, reiners out there still showing into their 20’s and doing well, we had two, one that still won championships.
Best of all, is your horse, your choice.