The core training Ski Mountaineers do should be as functional as possible. Your core is basic to many of your sport specific movements, such as poling, uphilling, or turning. For example, the more force you can exert on your poles, when double-poling across a flat section of a downhill, the faster you will go. Strength correlates nearly perfectly with speed in this example.
Core is important in other ways as well; especially in turning the skis, in bringing the trailing ski forward when skinning, or bringing either ski around to execute a kick turn. The goal of sport-focused core training is logical and simple: to strengthen the weakest link in the full body chain.
ALL full body movements originate with the core musculature.
Your core connects your arms and legs. Ski Mountaineering and SkiMo racing are quadrupedal. The poles are not just for balance.
A strong core provides a solid base from so that the big prime mover muscles of the limbs can do their job.
A weak core exposes you to injury.
Strength in your core will later become the foundation for endurance.
If you want to know what the best 10 exercises are to strengthen your core as a ski-mountaineer, see