Swimming is still the best exercise for surfing. Without heaps of paddle fitness it doesn't really matter how flexible or powerful you are. Its all about how quickly you can paddle into a wave and the amount of time you can spend in the water.
Good paddlers will dig there arms in strong and deep once or twice to catch the wave, others will flap there arms around and not really get anywhere.
1. Warm up - Rower: 10 mins, moderate to high. Remember to keep good posture.
2. Swiss Ball
a) shoulder press: sit on ball and raise weights up above your head. Do 2 sets of 15. (I use 4kg weights, but I'm a lil' girly so you may wanna use heavier)
b) chest press: sit on ball and roll out so your head and shoulder's are resting on it, keep your back straight and raise weights above your head. 2 sets of 15. (I use 3kg)
c) lat raises: lie with your chest on the ball and arms in front of your, wrists together, raise arms so they are parallel with your head. 2 sets of 15. (2kg)
d) pylo press ups: (not on the ball) like a normal press up but "jump" your arms off the floor when coming back up. 2 sets of 15 (this helps with popping up if you can do this, then actually pop up)
e) crunches: on floor or ball. Youd on't have to raise your body or twist it. The key is to tense your stomach muscles then do little ones. 3 sets of 15.
f) sideball roll out: kneel on a mat with your knees together, have one of the balls to your side and rest your arm on it, then roll it away from you and back again. Works the side and back where most surfers get injuries. 3 sets of 15 on both sides.
g) back extention: lie on the ball on your chest and do small raises. 3 sets of 15.
h) toes to floor: this looks so silly! roll over the ball so only your feet are on it, kinda like when you do a wheel barrow race, then roll the ball useing you legs till your feet almost touch the floor. Helps build balance and strength. 3 sets 10 on each side
i) superman: I refuse to do this in public and am gonna buy a ball to do this on at home. Lie on the ball on your stomach and then raise your left leg and right arm, then your right leg and left arm. Builds balance and strength. 3 sets of 15.
3. cycle or cross-trainer (cycles best) 20-25 mins on the hill/interval programme. This will help to keep your heart rate elevated with short powerful bursts.
Make sure you seek proper medical advice before undertaking any kind of rigorous exercise.