i bought this thing because i thought it would help with the fact that i get backache from lying down while i'm gaming. i was wrong. i pumped this ball up to the most that i could do it without the pump forcing itself back out, only to find that you are near enough sitting on the floor. i'm 6ft2ins so i'm not the shortest of people but for a product of this price, you would expect it to be usuable for someone taller than 4ft. my mate even tried it out, he's about 5ft6 and even he found it hard to sit normally on it. you end up having to sit with your legs crossed on it to be able to sit upright. if i had known this before buying it then i would have bought a normal exercise ball that normal sized people can sit on.