Why do humans swing their arms as they walk? Riddle answered(news.yahoo.com)
news.yahoo.com
Why do humans swing their arms as they walk? Riddle answered
http://news.yahoo.com/s/afp/20090728/sc_afp/sciencearmsoffbeat
http://news.yahoo.com/s/afp/20090728/sc_afp/sciencearmsoffbeat
More discussion there.