my 02 is ronson is onto something. if your into training you know that you can train for endurance or strength and modify your work out for anything in between. you can train for strength but strength isnt the problem if you can hold on in the first place. its endurance and the little bit more strenth you need will naturaly come. like said light weight high number of reps and then stretch those muscles. usually the reason muscles fatigue is lack of conditioning or lack of blood flow or circulation it helps me before i do anything including riding that is physical in nature to warm up slightly.get the juices flowing. then just try to relax myself imediately before i begin. arm pump is nothing i have ever had a problem with one because of the slowness of which i ride with and two i beleive because of wrestling seasons workouts including climbing the ropes chinups etc all develope those muscles and the extensive cardio work out in those practices(those that have participated know what im talking obout) one other thought on circulation is if you are breathing really hard and tired your heart and or lungs are struggeling to keep up with your bodys demand for oxygen which will fatige any muscles in need so for some a big help could be just some good extensive cardio work out. I prefer the jump rope for one. I dont personally believe you can overtrain except if you push to the point your body can not recover between workouts!