Because running includes many things: long-distance running around the playground, endurance running, explosive sprint, weight-bearing running and so on.
Frog jumping can include squatting, duck walking and so on.
The most effective way to exercise leg muscles is to do the above. Especially leapfrog. When I was a child, I practiced leapfrog in the martial arts school, and that feeling is really fresh in my memory.
Reference: you can choose continuous vault (more than 2 people are needed), squat with weight and jump on one leg. We can find a step, grab the step with two toes, leave the heel outside and keep the toes up and down, which can also exercise our leg muscles.
If it helps, please adopt it in time!