Translation of "отбивать" in English

Мы будем отбивать ритм секундомера —

We're going to be tapping at the speed of a ticking stopwatch -

Начните легонько отбивать ритм секундомера —

Begin very lightly tapping on your legs at the speed of a ticking stopwatch -

и начал отбивать упражнение на ногах, совсем легонько.

and I began doing my drumming exercise on my legs, very lightly.