Sleep is important for maintaining good posture and preventing back pain. Soft mattresses can lead to a rounded, hunched over spine. Firm or extra firm mattresses keep your body in alignment by providing support throughout the night so you maintain better posture during sleep without waking up with soreness from improper positioning of your joints.
Athletes need to sleep, in order to keep up the pace. Elite athletes are no exception: how they get their rest is vital for performance and recovery. They have different needs than most people though because as elite athletes they don't just compete on game day but many days each week!