In the middle of winter, with 17 hours of darkness, 500 competitors head north of Inverness for one of the world's toughest mountain bike races - the Strathpuffer 24-hour marathon. Conditions are testing, with ice and mud pushing the competitors and their bikes to the very limit.
Also in this month's show, exploring the attraction of night-time mountain biking, heading into the wintry hills with mountain expert Cameron McNeish and an investigation of Scotland's bid to host the Orienteering World Championships.
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