|Go for strength over showy|
In thinking particularly about Nordic skiing, the core is hugely important. Without adequate core strength, you will often see people skiing with their hips behind them, gliding with their weight predominantly on their heels instead of more appropriately, on the ball of the foot. Furthermore, a lack of core strength will manifest itself in the form of a cranky lower back after your first few skis of the season. Because skiing is such a dynamic sport, demanding that you be in a forward-leaning position and alternating between tensed and relaxed, you need a sturdy core to take the load off your lower back.
We prefer a max strength approach to core training, as opposed to the "1000 crunches every day" routine. Yes, you will get a ripped tummy with that many exercises (provided you're not snuggling up with Mr. Goodbar thrice a day), but will it make you stronger? We go for few reps and a high load to get maximal engagement of the core, complete with (and this part's crucial) correctly-fired muscles. Put another way, you want to engage your deeper core muscles INSTEAD of your superficial rectus abdominus. The easiest way to do this is, when doing a sit-up, focus on pulling up your pelvic floor; pretend your trying to hold in a pee. You'll notice your stomach contract and tension in your pelvic region, distal to your navel.
For a more visual reference, picture this: when you're using mainly your rectus abdominus in a sit-up, it will bulge from your stomach, mimicking a "bread loaf". Our good friend Dr. Colleen Ryan, DPT, coined that term and we think it fits very well. In contrast to the bread loaf look, an engaged deep core will display a flat stomach:
|The incorrect engagement - note the "bread loaf" abs. Notice also how curved the cervical spine is; a true, challenging sit-up involves a straight back, relying more on the deep core muscles instead of "rolling" along the spine and using the rectus.|
|A flat, sexy stomach in a sit-up is a sign of a strong core. See as well how the spine isn't as curved; when conducting the sit-up be sure to have the neck at a natural angle, as it would be if you were standing upright and looking straight ahead.|