In Horse racing betting and trying to pick a winner~ Figuring out the stage of growth and how horses run at different ages is very important.
In relation to the fitness of a horse age does play a huge factor in this. A horse is an animal and the trainers job is to get him physically fit and try to keep him there.
Here is a general breakdown to give you a great frame of reference with age.
AGE 2
Horses Start to race as Juveniles at the age of 2. This is the first year a horse can race
These are the youngest and the babies of the horse racing game. They are kept together and only race against other 2 year olds.
two year olds are not as fast as the older horses and usually do short sprints in their races.
Keep in mind they are still developing and growing. They are much slimmer and weaker than the older horses.
They tend to run as fast as they can as long as the can which is important to know because speed handicapping is a key with these young 2 year olds when horse race betting. They run hard and go all out because lack of maturing and seasoning to reserve any energy at all.
There is generally a low level of training at this age.
Speed is the trump card with 2 year olds and Front Runners will discourage some of the others if they get a real fast break
Look at the top barns for the good front runners for an edge with these 2 year olds
Fast workouts and speed figures is what to look for and five furlongs or longer is preferred faster than 12 seconds per furlong shows some degree of developing stamina
Age 3
They are still considered young and are separated from the 4 and older most of the racing season
Handicapping three year olds is much different from horse race betting on two year olds. Three being the most difficult age group to handicap with their rapid development sometimes just between races
Keep in mind three year olds can get good or bad very quickly
Look for improving 
