How do you build forward energy in a young horse that is naturally lazy or dull off the leg?

A young horse that is naturally low-energy or dull in its response to forward-driving aids presents a different starting challenge than a hot, reactive horse, and the specific approach to developing genuine forward energy is one Clinton Anderson addresses directly in his colt starting program. Anderson's diagnosis of a lazy young horse is specific: the horse has not yet learned that leg pressure is a signal that requires a response. It is not lazy by nature — it is unresponsive because it has not been taught that unresponsiveness has consequences. The training task is teaching the horse that leg pressure means move forward, now, and that not responding leads to a more significant request that the horse will want to avoid. His method for developing forward response uses his Driving Game: rhythmic pressure from behind — tapping the hindquarters with a stick, slapping the lead rope — that escalates in intensity until the horse moves forward, then releases completely and immediately when the horse responds. The key is that the initial ask is light, the escalation is rapid, and the release is immediate. A horse that learns the light ask is the warning and the escalation is the consequence learns to respond to the light ask quickly to avoid the escalation. Transferred to under saddle, the same principle applies: a light leg aid is the ask, and if there is no response within one or two strides, a reinforcement follows — a tap of a crop, a more insistent leg. The moment the horse moves forward energetically, the aid releases completely. Over repetitions the horse learns that the light aid means move now, and the forward energy becomes genuinely established rather than requiring constant driving. Anderson notes that horses worked extensively at slow gaits without this forward-energy development become increasingly dull over time — the slow work reinforces the slow response. Building forward energy first, then adding collection and refinement to that energy, produces a more athletic, responsive horse than trying to collect a horse that is not genuinely forward.