Always keep in mind that training with Pro-trainer is the same as driving up a hill.
The pressure decides how steep the hill, and the pedal for how long the uphill.
Training Of Young And Older Horses Is Basically The Same. The Figures For Young Horse Are Within Prentices.

Three Groups Of Training.
Group 1: Strength Training for horse that lack muscle.
Group 2: Basic Conditioning for heart and lung capacity.
Group 3: Lactic Acid Training For Endurance.

GROUP 1:
Strength Training is a very important part of training, especially for young horses who’s muscles is an important protection for tenants and ligaments. It’s important to start strength training already at 1,5 years of age so that the horse develops "real" legs for future training. It is common knowledge that missed training between 1,5 and 2 years of age can never be recovered. You must be careful and be very observant when training a young horse. Today’s young horses have easy to get going and it is easy to drive them too fast causing injury. You can be much harder training a full grown horse where the earlier training have been too weak.

The Training Procedure.
This training is only about Walk Canter, in maximum 30 sec. intervals, to get variable contraction and relaxation of the Muscles. Because the horse quickly becomes stronger by this type of training it is not possible to recommend any right or special pressure. Therefore You must primarily look at the stride length which should be maximum.

Let the horse walk canter with very low pressure, and then gradually increase pressure. Notice how the stride length increases with added pressure. As pressure is increased, at a certain point, the stride length becomes shorter. At this point, reduce the pressure until the horse again reaches its maximum stride length.

When the horse start tiring and the stride get shorter, reduce pressure to maintain maximum stride length. Here you must be very observant of the signals from your horse.

In the first period of training it’s enough to drive for 10 minutes, 10 x 30 seconds interval. Gradually increase by time as the horse get stronger to 30 intervals. This training can be done every second day. It’s very important that the horse is warmed up before you start the pressure intervals. At least 20 minutes of easy trot without load. And at least as important after finishing the intervals to run the horse in light trot for at least 20 minutes to clean out the muscles.

To avoid that the horse get stiff and square?, after 14 days of power training, run the horse with a light wagon, sulky or speed-cart, in several 200 –300 meter ruches at maximum speed of the horse capacity, together with relaxing jog between the ruches. This is repeated every third day.

For Example, Power wagon for three days, Ruches for two days, and two days of rest, used in a suitable mix. The Idea with this training is to quicken, strengthen, in the newly added muscles. To Develop the horse mental health and general relaxation it is recommended to drive the horse one day a week with a light wagon in "jog trot" along quiet roads in the woods. After This training You Should have a peppy and vigorous horse with legs that easily carries up the body.

GROUP 2:
Group 2 Training is to develop the heart muscles and lung capacity, which will provide the muscles and the mental functions with oxygen. This is often called "ground conditioning" and this is accomplished with so called Quantity Training.

Defining Pressure.
Now we need to define the word "Pressure" which is a measure of how much load the horse pulls. To make this easy to understand we use the outer scale on the pressure gauge that is graded in Mpa (MegaPascal). This scale is graded 0-25 and when you multiply the pressure with 2, you get how many "KILO" that the horse pulls. Example: If you set the pressure to 12MPa, x 2 = 24 kilo.

The Training Procedure.
Here all training is trotting. The pressure should be 6-7 (4-5), The Length should be 60 seconds, and the speed approximately 25 km/h = 2.24 tempo.

Release the pedal and let the horse run without load for 1 – 1.5 minute, Then press down the pedal again and repeat the 60 second load run, Followed by running free again for 1-1.5 minute, and so on.

Begin with 10 minutes (=4 load runs) and increase gradually to after a month reach 45-50 minutes (=20 Load runs). The Pulse Should Never exceed 170-180 beats/min. Train every second day, in between keep horse in corral. In Addition One day a week, train with light wagon doing "Rushes" as explained in Group 1 to retain quickness, vigor and sting under this training period.

GROUP 3:
Now we will make sure that the quickness, vigor and sting will last all the way to the finishing line. It Is The Lactic Acid that causes loss of power in the muscle. This in turn causes injury to ligaments and because of this the Group 3 Training is especially important, perhaps the very most important. Here the pulse beat measurer is of outmost importance to give you the pulse during hard load.

At approx. 200 beats/min the production of lactic acid starts. The object is to raise the threshold where the acid starts to produce, lengthening the time before the legs lose their strength.

Note! Operate the pedal smoothly, easing on the load, avoiding sudden jerks.

Start with a good warm up. Set pressure to 8-10 (6-7) and drive in 1.5 tempo = 33 km/h (2.00 tempo = 30 km/h). Let the pulse meter decide the length of the intervals. When at 200, try to maintain it for 300 meters by either holding back or encouraging the horse. Then release the load. Notice how the pulse rate slows. If it doesn’t, reduce the speed until the rate is down to 100-120/min.

Then apply the load again. Make sure to keep the speed 33 km/h. Let the pulse rate again climb to 200.
Start out with 3-4 intervals, and end the Group 3 Training when the horse can do 8-10 intervals.

ADDED INFORMATION:

The pressure on and the pressure off elements of using the Pro Trainer is fundamental and the pressure off periods are just as important, if not more so than the on periods.  The partial recovery is paramount as that is where you manipulate the anaerobic values by the length of the rest periods.  The partial recovery with the PT helps focus in the top-line, back, loins and glutes.