People with these conditions would usually feel the shakiness if you stand on the vibration machine for long period:
People with any of the conditions above cannot stand upright for more than 10 minutes. You can opt to sit on a chair, place your feet on the vibration machine to work on the legs. Vibration time is best to be around 30 minutes and rest for another 30 minutes. There is no limit on how many times you can vibrate. Of course, the more the faster you can see the results.
Such vibration exercise will not cause knee or joint pain. In fact, it can activate the knee joint! However, if the knee joint is in an acute inflammation period, should stop using the vibration machine for the time being and resume the vibration after the condition gets better.
Sit on a chair and place your feet on the vibration machine and work on the legs for continuously one month. Then, you may try to stand on the vibration machine in a slight squats position. If you feel tired, sit back and resume to the initial feet vibration exercise. Be persistent and you will notice the improvement on physical condition!