Trikes, Recumbent Bike Gains Popularity With Older Riders

David Lawson first tried a recumbent tricycle when his chiropractor told him that commuting to his job at the University of California, Santa Barbara, on a mountain bike was wreaking havoc with his neck and posture. Lawson had been an avid mountain biker for years and was determined to find another exercise he enjoyed. ...
http://www.aarp.org/health/healthy-living/info-07-2011/recumbent-trikes.html