Here is what Bonnatti thinks about the benefit of skiing: “My attempt on the Walker Spur in winter was a secret project (year 1963). Together with Cosimo Zappelli we intended to do the climb by the straight-forward method of reaching the mountain, climbing it, and descending to the valley in one single thrust, relying only on our legs, without help from helicopters or communication equipment. If, as we hoped, we succeeded in our aim, the winter ascent of the N face of the Jorasses would not only be a personal affirmation of our principles, but it would also pay homage to the established traditions of mountaineering in the true spirit of the generations that had preceded us.
I reached perfect physical fitness not by climbing difficult rocks but by downhill skiing. Those who knew me were astonished to see me suddenly become an assiduous habitué of the ski slopes. But the truth was, for each trip up in the ski lift there was an uninterrupted series of short-swing turns down the fall line, on the most secluded and uneven slopes, in deep snow in poor condition.”
text from: “The Mountains of my life”, by Walter Bonatti