I'm a freshman who's weak. I can't do more than one pushup, and I can do like 30-35 situps in a minute. It's not looking good all around. I'm 114 lbs., 5'6", and a freshman with decent 8/16/32 times. Is getting stronger in the core and (mainly) arms going to do anything substantial for any of these races? 800m maybe? I'm just wondering if this is something that'll help me significantly drop my times or if it's just an add-on that'll slightly help out with performance.
800m: 2:13
1600m: 4:59
3200m: 10:33
Track mileage: 10mpw