There are some elements that you should consider when talking about surfing fitness. Common sense tells you that you are going to need upper body strength, but there is a lot more to it than that.
Surfing Fitness – Cardiovascular
Surfing for awhile at a time is going to take endurance. You will need basic stamina to surf for extended periods of time. For those who are looking into surfing to try, or those looking to get better at surfing; there are certain things you can do to improve your stamina. Exercises like jogging, running, swimming laps, and aerobics are all endurance exercises. If you do these at a steady pace for twenty minutes at a time, you will see some improvement.
Upper Body
Surfing fitness in the upper body requires strength in your shoulders, chest, back, and the triceps of your arms. You should do light strength training (like light weight lifting) that focus on these areas. Butterflies and pull-ups are great examples of the types of exercises you should consider to increase your upper body strength. Another that you might want to try would be rowing. This will also help build up the strength in your back, as well as the deltoid muscle across the top of your shoulder. You will need these muscles for all the paddling you will be doing.
Surfing Fitness – Lower Body
Surfing fitness in the lower body not only requires strength, but balance. To improve strength try doing lunges and squats. For balance try using a stability ball. Another approach, though some guys would be hesitant to try it, would be yoga. There are a lot of poses in yoga that require you to keep your balance, and holding them for a couple minutes requires you to use the muscles to actually hold the pose. This is a lot like holding your stance while on the surf board so it could greatly improve your surfing.

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