Monorole training is 1 position training. For example Pressure for PG. This means only 3 guys per week can get required 48 minutes for a full training.
Being in D.V, you can use also 2-position training, but don't waste it on a high potential guy (Perennial allstar and upwards). From D.IV and up, 2-position training gets you nowhere as you fall back too much compared to the teams that do 1-position training.