Check your self-competition or need to one-up the lady lifting next to you at the gym door. Instead, get some good advice from a trainer or strength and conditioning coach to find out an appropriate amount of weight for your body size, fitness level, and goals. From there, gradually add weight, being sure to listen to your body when you are struggling to do another set or just get the dumbbell off the ground. Remember that being challenged is good but lifting to the point of muscle failure is not.
Bob Mack, S-S