First of all…
You will only improve your surfing skills… by surfing. As with any other sport or ability.
Premise #1.
If you follow a training program that includes resistance, cardio, and flexibility you will surf more efficiently: paddle better with less effort, stand up faster, and be able to perform more and better maneuvers.
Premise #2.
Both very new beginners and intermediates/advanced surfers (will) benefit from a training program adapted to their needs.
Premise #3.
Premises apart, let’s go down to business
Beginners to the training program, this is for you all:
Regardless of your surfing level and if you’re new to training then you should start settling down your base of strength, cardio, and flexibility. Working out the whole body and giving different stimuli on cardio would be nice as a start for the, let’s say, the first month. You want to be doing this while surfing along the week (remember premise #1?). If you surf on Mondays and Fridays you complete your surfer workout session on alternate days: Tuesdays and Saturdays for example. Individualization required.
If you already workout for more than 3 months…
…then it’s time to include power training so you can stand up even faster, have an even more efficient paddle stroke, and be able to perform maneuvers easier since your core is rock solid. Power training means higher load intensity/stimulus. If you work out with weights this is done increasing the exercise weight in order to perform 3-8 reps. Bodyweight explosion work also fine. What we want here is to make the brain fire more messengers to the muscles.
Regarding safety, posture, and technique these training protocols require supervision.
Isn’t all about muscle power training! What about the heart?
Surfing, as opposed to all the land sports, is performed in a marine context.
It’s ok you run, do your cardio at the gym or home/street HIIT: you will improve that function for sure and your heart will be more proficient.
But (there’s always a but right?): in order to get better results, you want to go to the water swimming or paddling. Not surfing. Same way swimmers do their training sets, so we should do. Principle of specificity.
Bottom line
Keep your surfing sessions, it’s the only way you improve your skills.
Add a training program to your routine. Progress to power training to increase your speed, power, and response to a stimulus.
Include water paddling sessions to maximize your paddle strike and overall muscle endurance in the water.
Don’t forget to do static stretching at the end of your surfing sessions and workouts, you’ll feel much better.