A dynamic training system provides elevated load and energy demand on a rider of a moving bicycle out on the road or track. Resistance to movement of the bicycle is provided by a resistance unit which may include an eddy current brake. A processor may generate a control signal that adjusts the resistance to replicate the effort of riding a predetermined course or training protocol. Multiple riders at different times or locations can compete on a common virtual course. A stronger rider can be restrained by a heavier imposed load to keep pace together with a weaker rider, without compromising total power expenditure to keep the riders together.