Effect of temperature on race times

A few years ago, the major racetracks in California introduced synthetic tracks. It was hoped that this would give a more consistent surface and lead to fewer casualties than either turf or dirt tracks. In general, this has proved to be the case.

However, horses often run more slowly on the synthetic surface than on dirt. Furthermore, it has also been noticed that race times vary with temperature.

A study conducted at the Del Mar Racetrack in California monitored the change in temperature during the day and compared it with the speed of horses running on the track. Lead researcher was Dr Mick  Peterson of the Mechanical Engineering Department of the University of Maine.

The research team measured air temperature, the temperature on the track surface and at four depths within the track. These measurements were recorded throughout the day over a 42-day period

They also recorded the fastest times for 6-furlong (1.2km) races, which took place in the afternoons, and the times taken for fast training 'work', which happened in the mornings.

Inspection of the data showed that horses ran more slowly in the afternoons. This correlated with changes in air temperature and the temperature of the track surface and subsurface.

Higher afternoon temperatures were associated with slower racing times. The fastest times recorded during the afternoon races were slower than during the morning work sessions.

Why should this be?  A possible explanation could be found in the characteristics of the wax used to coat the fibres. Within the range of temperatures experienced during the day was the temperature at which the wax started to undergo thermal transformation - i.e. melt.

The scientists suggest that the physical properties of the wax may underlie the effect of temperature on track characteristics.

They suggest that further work in the future should include a study of the various components of the racing surface, to identify the component responsible for the change and to assess any influence it might have on the risk of injury.