If you’ve paid attention to what the other magazines have written about ab training for the past two decades, you might think that your hip flexors were the only thing holding you back from having ripped abs. Because most people spend so much time sitting, the hip flexor muscles get short and tight, and they can inhibit the abs from firing by taking over the movement on ab exercises. The solution some trainers offer is to eliminate involvement of the hip flexors as much as possible by trapping the feet or performing shortened ranges of motion.
We say that’s crap. The better fix is to stretch your hip flexors and strengthen them along with your abs, which allows for more functional ab training. Strong hip flexors let you run faster, skate harder (if you’re interested in playing ice hockey this winter), and throw more powerful kicks and knee strikes (if you’re a martial artist). The sprinter sit-up works both the abs and hip flexors.
How to Do It
■ Lie on your back with arms at your sides and legs extended. Explosively sit up as far as you can while driving your left arm forward and your right knee to your chest. Reverse the motion but try not to let your torso or legs rest on the floor for even a moment. Repeat on the other side. The motion looks somewhat like you’re sprinting.
■ The instability created by moving each leg and arm alternately forces the core to work hard to balance you, so while the driving of the knees certainly activates the hip flexors, that won’t take away from the stimulus your abs get. (You’re also doing a full sit-up.) Need more proof? Look at the abs of any champion sprinter. They don’t suck
