There are two factors that slow down a race horse in full stride - turns and other horses.

These factors are even more important at a half-time track such as Charles Town than at the mile tracks like Pimlico, Bowie and Laurel.

At the half-mile tracks where the physical makeup of the racing plant encourages heavy traffic, the short, sharp turns requires nimble horses and alert jockeys.

The half-mile scene is unique in that the racing secretary will write restrictive conditions that in effect make a distinction between even the lowest claiming horses. That means that almost every race is a wide-open affair. This keen competition at the halfers makes for a lively game, indeed.

At the mile tracks, horses have a good chance to get a desired position before the field comes to a turn, usually one with a wide radius. With time to get position, plus the more sweeping turns, the horses can be eased around the turns because there is more straightaway later on. Therefore, at the mile tracks a handicapper can get a pretty good picture of how the race will be run. And the horse that wakes up with the most energy on a given day wins the races.

Not so at the halfers. The horses there are so evenly handicapping factor takes on more significance. Post position, weight and pace become vital considerations. The jockey can be the most important factor. One that can break well, handle traffic when necessary and "ride" a horse round the sharp turns rather thsn let the animal do it all on its own, has a decided edge.

The best half-mile jockey of recent memory was Ronnie Barnes. Barnes was sharp at the start, fearless and quick in traffic and, most importantly, used his knees and hands so well that almost all of his mouths would negotiate a turn like a hoop around a barrel.

Other half-mile stars like Jesse Davidson, Bill Passmore and Tony Agnello were eagier. But none could get a horse to run from gate to wire with more dispatch, particularly in the shorter races. Those abbreviated events require instinct, nerve and pure horsebacking ability. Their skills are like those of kickoff and punt return specialists in football.

The horses at the halfers are usually inferior to those running at the milers. This is due in large part to the better purse structure at the latter ovals. Butvmany obviously superior horses from the milers get whipped at the halfers because of the turns. Some railbird theoreticians explain this by saying that the proven half-mile horse is more "left-footed than his apparently superior brothers from the mile circuit.

Races in the United States are run counterclockwise and our horses are continually turning to the left in races. It follows that the left leg does most of the guiding.

An interesting series of experiments was started on left-and-right-footed horses in Kentucky about 12 years ago. Like humans, horses are stronger on one side than the other.

Imagine the advantage a breeder would have on his competition if he knew that Bold Ruler. Princequillo, Count Fleet and Secretariat were all left-footed. Perhaps the group that started the experiments discovered that here was indeed an edge in determining the horse's strongest side and are sitting on the information for obvious reasons. In any case, there are horses who, by their style of running, are better suited to half-mile racing than their more illustrious counterparts from the mile tracks.

Betting at the mile tracks requires more discipline than at the halfers. At the smaller tracks it is not uncommon for horses with ordinary form to come out of the pack of a well-matched field to win at a large price. Intuitive fans can score more often with this typw of racing, which can he likened to that of the greyhounds. Even the handicapping methods are similar.

At the milers most of the races are won by five or six big stables, usually at small prices. It is hard to bet on them and hard not to. It requires sharp handicapping and sophisticated handling of one's money to show a profit, the bottom line in any competitive enterprise.