This is a great workout that combines a lower body exercise with an upper body exercise.
It would be very challenging to do all 8 Tabata exercise rounds if you were to do pull ups alone. For example, if you could do 10 pull ups in 20 seconds on average, you would have to do 80 pull ups in total which is a big challenge for most people.
So the smart way to incorporate the more challenging exercises is to combine it with an exercise that uses other large muscle groups. A Tabata “couplet” like the one shown below, allows your major muscle groups to get 30 seconds of rest before it is called upon again to work!