I'd work on your Latisimus (triangle wedge in back), Deltoids(Top of shoulder), Pectoralis (chest), Forearms and biceps, Quadraceps & hamstrings (upper legs) In the gym:- To work the muscles listed above machines or exercises you would need to complete are as follows Latisimus - Vertical traction machine Deltoids - Shoulder press machine, Dead lifts or Handstands Pectoralis - Chest press machine, Bench presses, press ups Forearms & Biceps - lift dumbells, chin ups/pull ups, tin-tank;) Quads & hams - Leg curls and extensions If you want to increase your muscular strength, You would want to complete a small number of repitions of these exercises lifting heavy weights (80-100% of your one rep max(One rep max = Greatest amount of weight you can lift)) For example On vertical traction (lats) my one rep max is 100kg, So I would lift 80-100kg 10 times in one set. If you want to increase muscular endurance ( stamina, stop you getting tired quicker) You would lift a smaller weight more frequently. 40-60% of your one rep max For example Vertical traction 100kg one rep max, I would lift 40-60kg 50 times in one set. But I would try Mountain climbing, There is some great indoor surfaces across the UK I would also use a rowing machine, or go swimming, as these work most of the muscle groups in the body Just to try and stay active over the winter When the weather blocks riding EDIT: Not Just copied from wiki, BrianMac, BBC etc.