66 thoroughbred trainers where studied in Voctoria, Australia.
The researchers found that the intended training workload was not associated with trainer prize money once other factors were taken into account, but more frequent rest breaks were associated with greater prize money per start earned in the previous season.

They found that the intended training workload was not associated with trainer prize money once other factors were taken into account, but more frequent rest breaks were associated with greater prize money per start earned in the previous season.

Intended training programs with moderate galloping distances as horses gain fitness for racing (that is, not too high or too low compared to their peers), and moderate times between race starts were associated with better rates of wins and places.

Pre‐trial total galloping distances between 7500m and 15,000m were associated with a higher rate of career wins, and previous season wins and places per start.

Slow‐speed galloping distance to trial between 5000m to 12,500m was associated with a higher rate of career placings per start, with reduced performance being evident over 12500m.

Greater time between race starts was associated with a greater rate of previous season wins and prize money per start until three weeks between starts, with a decline in performance noted thereafter. Between 2.5 and 3 weeks between races appeared to be optimal, they said.

A greater frequency of rest breaks was associated with greater prize money per start earned in the previous season.

“These finding suggest that there is considerable scope for future modification of training workloads without negatively impacting trainer success rates and prize-money earnings.”

The trainers who used the lowest and highest total or slow‐speed galloping workloads as horses gained fitness and prepared for racing had fewer wins and places, indicating that a moderate workload appeared to be the sweet spot for training.

“Our findings and those of others are consistent with the lowest and highest volumes of galloping not being conducive to maximising horse performance.

“However, in horses in this study it was the volume of galloping in preparation for training that demonstrated that association rather than gallop volumes once horses were fit to race.

“It is possible low workloads are not sufficiently preparing horses for race‐level fitness and that horses trained over long distances are over‐trained.”

Source: Horsetalk.co.nz. the study is at mdpi.com.