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Work out every other day. And constantly move up in weight. For example, do 4 sets of 6 reps on the benchpress. Do them (just an example), 225-230-235-240 Every 2-3 workout sessions you have to force...
Well swimming is brilliant. I have been doing hard training 4 times a week and have built up my arm strength in just a month!!! Running will build up leg strength and the gym will be buliding up...