I am a 14 year old girl who is 5 foot 4 and weighs 109 pounds. I work out at gymnastics for 3 hours a day, 4 days a week and go into a 'real' gym for aprox. 4 hours over the weekend. I jog a mile everyday and stretch for at least 1/2 hour every day. I do sit-ups, push-ups, crunches, toe raises, bicycle crunches and many more excersizes but am looking for an arm strengthening excersize to do at my house. Any suggestions?