When practise sport the treadmill self-absorption is important to dim the impact and the vibrations of articulations in lower extremities ( kneews and ankles) and the lumbar sacral area of the back.
The impact absortion is essential to avoid painful display and in a long-term avoid neuralgic swelling of great importance, too.
The treadmill made of artificial grass show us infinite advantages over its convertional equivalent made of rubbler band.