Jumping lunges: Jumping lunges provide a very intensive additional training stimulus. You start with one leg in front, jump up and change legs before landing. Your posture is otherwise the same as with classic lunges. You should pay attention to your torso stability and make sure you land softly.
Backward lunges: The movement of backward lunges is similar to that of forward lunges, the difference is just that you take the step backwards instead of forwards. The same muscle groups are involved, but the knee joint is not quite as involved. Backward lunges are therefore a good alternative for people with knee problems.