Here are 3 tips for you:
1. kids need to generate a pretty powerful vertical force in taking off in the long jump, and they need to learn to generate a more horizontal force in taking off on the hop phase of the triple jump.
2. The takeoff in the step and jump phases in the triple jump is a rebound takeoff, like the pogo style jumping of Masai Warriors. Kids need to understand the difference between the rebound takeoffs and the regular takeoffs which occur in the long jump and in the hop phase of the triple jump.
3. The best workout for the triple jump was designed in the 1950’s by Yuri Verkhoshansky. On a football field, going 20 yards per “pass”, do multijumps for distance. First, multihops, (LLLLLL, then RRRRRR, then do multisteps, LRLRLR, then do multi hop-steps, LLRRLLRR. Do each of these two times, (a total of 52 bounds) working on upright posture, keeping the feet dorsiflexed, and uppercutting with the drive arm.
I have my jumpers do this workout 1-2 times a week - that’s it.
I would use other drills if I thought they were necessary, but in the past 10 years I’ve coached 11 high school state champions, 4 Junior Olympic national champions, 4 Track and Field News High School All-Americans and 4 NCAA D1 All-Americans- all in the triple jump, using just that one workout!