Finally got a bike that fits me well and found no back or knee pain while riding. I went on relatively short rides as i'm new to the sport, but took my first adventure on Sunday morning for a much longer ride and it was amazing fun. Within a day my elbow and forearm starting hurting something fierce. I saw a video where a guy said that to avoid eblow pain you should be holding the handlebars and breaks like a feather, barely grasping them, and supporting your upper body with your abdominals. I understand the importance of core strength for cycling, but this advice seems to be rubish. I don't believe there is a rider or human on the face of the planet that has abs / core that can bear the weight of an upper body for 5 hours without reaching muscle failure repeatedly.

Anyone have any advice or tips that can cure this problem?