As they get older, the most successful jockeys go on to compete in regional races on neighboring islands, including Lombok, a popular tourist destination, where jockeys continue racing past 14.

Asikin Bin H. Mansur, 47, is a horse trainer whose two adult sons, now 25 and 18, were jockeys. His boy Adi, 7, was competing in this year’s Police Chief’s Cup.

“I worry about him falling and getting hurt, but it is a tradition here on the island and in my family,” Mr. Asikin said. “Sometimes if he falls, he gets injured and sometimes not. If Allah wants him to be injured, it’s his destiny.”

Adi, playing with friends between races, said, “I like racing and don’t get scared,” though he admitted he misses going to school when he’s away racing.

The 7-year-old qualified for a final in Bima and came in fourth, winning the owner a refrigerator.

Adi’s father seemed pleased with his son’s haul for the week, about $162. “A little less than I hoped for,” Mr. Asikin said, “but it was a gift from Allah.”