John Frank Cadman (born 27 March 1934) is a former English cricketer and field hockey player who competed at the 1964 Summer Olympics. Cadman was a right-handed batsman who bowled right-arm fast.
Cadman was born in Colchester, Essex and educated at Friends' School, Saffron Walden and Loughborough University. Cadman played field hockey for Kent and Essex at county level and avarious clubs at club level.
He played for Canterbury Hockey Club, Southgate Hockey Club, Chelmsford Hockey Club and Saffron Walden (the latter because of his teaching job at Friends' School). He introduced hockey to the school in 1960.
He was the Hockey Association national coach and represented both England and Great Britain. He was called up for his England debut against Scotland on 23 April 1960 and represented the Great Britain team at the 1964 Olympic Games in Tokyo.
As a cricketer, Cadman played 2 Minor Counties Championship matches for Suffolk in 1965, against Norfolk and the Nottinghamshire Second XI. He made his only List A appearance for Suffolk the following season against Kent in the Gillette Cup. In this match, he bowled 4 wicket-less overs and with the bat he scored 7 runs, before being dismissed by Stuart Leary.