Knee jumps are great plyometric exercises to develop an explosive and athletic lower body.
Plyometric exercises like knee jumps and box jumps are a big part of training camps for many athletes in sports where the lower body plays a major role.
Many sports athletes from football to track and field to MMA utilize them heavily in their training - and for a good reason because the transfer to athleticism is tremendous.
Knee jumps will develop the posterior chain (lower back, glutes and hamstrings), but many other lower body muscles are worked to a great extent as well. Expect to see nice gains in strength and size.
The biggest benefit of plyometrics is mostly neurological: your central nervous system will become more explosive and thus allow you to jump higher, leap further, sprint faster and kick harder.
Knee Jump Progressions
Two Leg Knee Jump
The easiest progression of the knee jump is to just take the kneeling sitting position and then jump to a full squat. Then return to the sitting position for the next repetition.
It's recommended to place some padding underneath your knees and shins because the motion can badly hurt your skin.
One Leg Knee Jump
One leg knee jump is clearly the harder progression because you are only using one leg to do the jump!
One leg knee jump requires significantly more strength in the legs but the exercise also requires balance, because you are balancing on just one leg.
You can begin practicing the exercise by just balancing on one knee. Test the range of motion by moving backwards and forward - this will build stability and balance!
Adding Box Jumps
Another way to add difficulty and overall effectiveness to the knee jumps is to do additional box jumps after the knee jumps!
This way the exercise becomes a continuous movement flow where you are jumping twice in a row without any time to rest.
How to Do Plyometrics
The goal of plyometric training is to train the explosiveness of the body - to produce real athleticism. It's fundamentally training the central nervous system - not about fatiguing the muscles.
As a result, low rep ranges where you feel the freshest possible should be utilized. You can take longer rest periods like 3 to 6 minutes and do only 1 to 5 repetitions per set.
Focusing on quality is the key to plyometrics, not the quantity.
Train hard, stay safe.