She explained that they would prevent me from holding my hands in a stressful position, and allow my arms to heal overnight.
她解释说这样就能防止我的手处于一个压迫的姿势，让我的胳膊能在晚上恢复。
2
It refers to the maximum limits which give the dealer the right to carry positions overnight. It removes the obligation to square the position every day.