It's just not possible to make a low impact tabata. By definition a tabata workout only has a 20 sec work interval that needs to to be done at as close to 100% of MHR as possible. This means you need maximum intensity to reach this level of fitness. Even most plyo moves wont reach a level high enough to be considered a true tabata work interval. With low impact the intensity is not as great as that of a similar plyo exercise, so the low impact move needs to be done for a longer period of time to have the same benefit and this kind of rules out making a tabata workout. Just because a workout follows the 20 sec work interval, 10 sec rest doesn't mean it is a tabata workout. It also needs to push your heart rate to as close to 100% of your MHR as possible.