Racing commentators, jockeys and trainers, as well as Racing Incident Reports and Comments-In-Running issued by the Jockey Club often mention the term "cover" in sentences such as "the horse had to find cover" or "the horse was obliged to race wide throughout without cover and gave ground over the concluding stages".

Very often, a horse's sub-standard race performance is attributed to its inability to obtain cover in a race. In fact, quite a number of horses perform very well when they have cover, but never without. What, then, is "cover"? Why does it act as a key factor for the performance of the same runner?

"Cover" means that a horse follows the others in the race and uses them as a form of shelter before its jockey asks it to quicken up in the closing stages of a race. Horses "without cover" are those that are widest on the track with no horse in front of them.

Some horses are front-runners. They love being allowed to race in the lead where they produce their best form. Other horses, however, are not suited to being in front and are better off being restrained behind the one in front. Now if a horse races too fast in the early or middle stages of race and uses up too much energy to soon, it will have nothing left to finish off the race with. The horse runs out of gas.

Horses tend to over-race if they do not have cover and are harder for their riders to settle. As a result, they may try and run too freely and "pull" against its rider's hold.
Therefore, if a jockey is riding a horse that is not a front-runner, the jockey will usually try and get some cover for his mount, where it is less exposed to the breeze, and where it travels in the slipstream of the horse in front. Here it can travel comfortably and finish the race off strongly when asked.

Most horses can perform best only if they can find cover in the run, especially those who race keenly or have little racing experience. The barrier draw is naturally an important factor in deciding whether a horse is likely to find cover or not. The higher the number, the further away from the inside, and the harder it is to obtain cover.

Nevertheless, there are, as ever, exceptions to the rule. Some horses prefer to have room in the run and don't like being covered-up. Olympic Express, the Hong Kong Mile and Hong Kong Gold Cup winner, is a good example.