LW4 is a para-alpine and para-Nordic standing skiing sport class defined by the International Paralympic Committee (IPC) for skiers who may have a disability in one lower extremity, which may be a result of a leg amputation below the knee, knee arthrodesis or a hip arthrodesis. For international skiing competitions, classification is done through IPC Alpine Skiing or IPC Nordic Skiing. A national federation such as Alpine Canada handles classification for domestic competitions.
Skiers in this classification compete with one or two skis and two ski poles, except in para-Nordic skiing where the skier must use two skis and two ski poles. Skiers in this sport class may have a specially made ski boot with a prosthetic built into it. Cerebral palsy skiers in this class may have better balance while using skis than they would otherwise. This presents challenges for coaches who are working with the skier. Compared to other skiers in the class, the skier with cerebral palsy may tire more quickly.
A factoring system is used in the sport to allow different classes to compete against each other when there are too few individual competitors in one class in a competition. The factoring for LW4 alpine skiing classification during the 2011/2012 skiing season was 0.9961 for slalom, 0.995 for giant slalom, 0.9901 for super-G and 0.9949 for downhill. In para-Nordic skiing, the percentage for the 2012/2013 ski season was 96% for classic and 96% for free. While LW4 was not grouped with others classes at an event in the 1980s, it became grouped with other classifications during the 1990s and 2000s. Eligible events for this classification included 1986 World Disabled Ski Championships, 1988 World Winter Games for the Disabled, 1990 Disabled Alpine World Championships, 1992 Winter Paralympics, 1994 Winter Paralympics, 1996 Disabled Alpine World Championships in Lech, Austria, 1998 Winter Paralympics and 2002 Winter Paralympics. Skiers in this classification include Australian Scott Adams and New Zealanders Steve Bayley and Patrick Cooper.