Originally, Native Americans and Indigenous people from other territories developed mounted archery for hunting and also to fight the adversaries. On the plains of the United States buffalo hunting was quit possibly the widest-recorded example of bow-hunting by mounted archers. Extremely gifted equestrian skills are imperative for this sport, since a bow requires the rider to release the reins and use both hands to shoot accurately at great speeds.
There are heavy or light archers, depending on the purpose, armor and weaponry. The medieval Mongols and Hungarians fielded both heavy and light armies. During some periods, the troops were extremely heavy as with cataphracts and knights.
The lighter horse archers were typically considered only skirmishes. The troops were lightly armed and moved rapidly to outrun combat, sending quick blows to the flanks or rear of the enemy. The skill of these riders was very important as sometimes it required them to turn the upper body and shoot backwards. Their speed caused great issues with their foes as they could not keep up with the attacks. And if the opposing army did attempt to charge, the entire battle was slowed down. The primary weapon used by these horse archers was harassment, which wore down their enemy psychologically.
Heavy horse archers fought, instead, by using organized and disciplined ranks. They did not harass but fought with volley after volley which weakened the enemy before they could even charge. Along with bows, they used spears and lances.
Today, there are at least a couple associations supporting Horseback Archery to include, MA3 - Mounted Archery Association of the Americas and WHAF - World Horseback Archery Federation. In addition, there are many training opportunities and clinics that offer horseback archery lessons. With a history dating back so many years, it is an interesting sport to perfect.