Physical endurance is a combination of things. For your upcoming HUMM start working on muscle endurance, cardiovascular conditioning and range-of-motion (stretching). We are each given genetic gifts of slow and fast twitch muscle fiber. Fast-twitch fibers provide explosive, burst strength such as boxers might use. Slow-twitch fibers provide long-lasting, low power, endurance. Riding a motorcycle for hours at a time is slow-twitch activity. If you do weight training (of course you do, you ride motorcycles right?) lighter weight and more repetition are the key. Lower body strength is more important than upper body. Why? Because your primary connecting with your motorcycle is from the waist-down. We DO NOT hang-on with arms and shoulders. If we do we lose fine motor-control of clutch, throttle and brake. A death grip on the handlebars will wear you down. Riders often carry too much tension in their upper bodies without realizing it. Fear of losing control is often the cause. Improving your riding skills and learning the limits of your bike will often lead to a more relaxed riding style. Visualize your primary attachment to the motorcycle as being from the waist down: Boots Tight to the Cases– Knees on the Tank– Toes pointed straight ahead.