Keep in mind that these distances are guidelines for training purposes. The actual distances ultimately depend on your horse's stride length as well as on factors such as weather and the surface you’re riding on. Remember that as fences get higher, the distances will need to be adjusted accordingly, too.

Distance Between Trotting Poles

Horses                                                       1.10 - 1.30 m
14’2  /  148 cm ponies                              1.00 - 1.10 m
13’2  /  138 cm ponies                              0.90 - 1.00 m
12’2  /  128 cm ponies                              0.80 - 0.90 m

For raised trotting poles, it’s best to reduce the distance by at least 10 cm. 

Distance From Trotting Pole to Small Fence

Horses                                                       2.20 - 2.50 m
14’2  /  148 cm ponies                              2.10 - 2.40 m
13’2  /  138 cm ponies                              2.00 - 2.20 m
12’2  /  128 cm ponies                              1.80 - 2.00 m

Distance From Canter Pole to Fence

Horses                                                       2.80 - 3.50 m
14’2  /  148 cm ponies                              2.70 - 3.10 m
13’2  /  138 cm ponies                              2.40 - 2.90 m
12’2  /  128 cm ponies                              2.10 - 2.50 m

For canter poles between two fences, it's best to place the first canter pole about 3.5 m after the initial fence for horses.
 

Recommended Distances for Practice

These are standard recommended distances between any two fences that you approach in canter. If the fences are smaller than approx. 1 m and you are riding a large horse, you may have to reduce the distances.

1 Stride

Horses                                              6.00 - 7.00 m
14’2  /  148 cm ponies                     5.90 - 6.90 m
13’2  /  138 cm ponies                     5.70 - 6.40 m
12’2  /  128 cm ponies                     5.20 - 5.80 m

2 Strides

Horses                                                       9.50 - 10.20 m
14’2  /  148 cm ponies                              9.40 - 10.00 m
13’2  /  138 cm ponies                              8.60 - 9.20 m
12’2  /  128 cm ponies                              7.70 - 8.20 m

3 Strides

Horses                                                       13.50 - 15.00 m
14’2  /  148 cm ponies                              12.50 - 14.00 m
13’2  /  138 cm ponies                              11.50 - 13.00 m
12’2  /  128 cm ponies                              10.50 - 12.00 m

4 Strides

Horses                                                       17.00 - 18.50 m
14’2  /  148 cm ponies                              15.70 - 17.00 m
13’2  /  138 cm ponies                              14.50 - 16.00 m
12’2  /  128 cm ponies                              13.00 - 14.50 m

5 Strides

Horses                                                       20.50 - 22.5 m
14’2  /  148 cm ponies                              19.00 - 20.50 m
13’2  /  138 cm ponies                              17.50 - 19.00 m
12’2  /  128 cm ponies                              15.70 - 17.50 m

6 Strides

Horses                                                       23.50 - 26.00 m
14’2  /  148 cm ponies                              22.00 - 23.50 m
13’2  /  138 cm ponies                              20.00 - 22.00 m
12’2  /  128 cm ponies                              19.00 - 20.50 m

7 Strides

Horses                                                       27.00 - 30.00 m
14’2  /  148 cm ponies                              25.00 - 27.00 m
13’2  /  138 cm ponies                              23.00 - 25.00 m
12’2  /  128 cm ponies                              21.00 - 23.00 m

Download the cheat sheet here.