Surfing champion Luke Landrigan shows you part one of how to get killer six-pack abs for the shirtless-appropriate season ahead. Time to sweat it out, boys!

Jackknife Sit-up
The jackknife sit-up, also known as the V sit-up, is an advanced abdominal exercise, which doesn’t require any equipment. It targets the abs as well as a few other muscles. While performing this routine, keep in mind to follow the proper form and not to use momentum, or else the exercise will be ineffective.

Place a mat on the floor. Lie flat on the mat with your legs straight and your arms extended above your head. Simultaneously lift your arms and legs toward the ceiling. Note that while raising your arms and legs to the jack-knife position, your arms and legs should be approximately parallel to each other. Lower your arms and legs and return to the starting position.

Complete 10 to 12 repetitions of this exercise per set. Repeat until you’ve completed two to three sets.

Aim to do two to three sets four days a week for six weeks to start seeing the results.

Weighted Sit-up
Weighted sit-ups are performed using weights to provide you more resistance. Depending on each person’s capability, there are also other forms of weighted sit-ups that can be used for a more personalized program. Routine: Place a mat on the floor. Sit on the mat with your legs straight and your arms extended above your head while holding a 10-lb weights. Slowly lie down, keeping the weights above your head. Remember to contract your abdominal muscles in order to control your descent. This controlled downward motion is actually the trick behind the weighted sit-up.

Perform 10 to 12 repetitions, completing two to three sets four times a week.
Photographs by Ronan Capili. Location: Pan Pacific Hotel.