Summer Biathlon is a warm weather variant of Winter Biathlon where the skiing is replaced by either running or occasionally mountain biking. This sport, which was planned as a promotion for the National Shooting Sports Foundation, began in 1987 with a race series in Memphis, Tennessee.
Summer Biathlon will typically consist of a 5 to 10 km run with two shooting stops. The course is divided into three loops with prone shooting following the first loop and standing shooting following the second loop. For both prone and standing shooting, competitors have five rounds to hit five targets set at 50 meters (for a total of ten shots). A 100m penalty loop must be run for every shot missed. Unlike winter biathlon, rifles are left in the shooting range on a rack. Competitors pick up rifles as they enter, and leave them as they exit the range area. For National and International events, there are rules and regulations which govern the length of the course depending on competitor class (Men, woman, junior men, junior women), the shooting distance, target size, rifle, and so forth.
For most events you will encounter in the US, novice (sport class) participants will usually be allowed to shoot from 25 meters and experienced (match class) racers usually shoot at 50 meters. The targets you will see in most races are either 3.5" metal knockdown targets - plates on hinges that are cheaply constructed but still in use by some clubs for novice events, or the standard winter targets, which can be set for 4.5 cm for prone shooting, or 11.5 cm for standing. Some events still adhere to the original practice of rewarding racers for hitting targets by subtracting 15 seconds for every prone hit, and 30 seconds for every standing hit from their race time instead of penalizing for shots missed. Marlin 2000 rifles are provided at most races, in addition to shooting instruction, ammunition, and targets.