Complex sentence: Fridgen was the assistant hockey coach at Union College from 1985-1989, an became the assistant coach of R.P.I. in 1989 and head coach in 1994, remaining until 2006.
Split into simpler sentences: Fridgen was the assistant hockey coach at Union College from 1985-1989. He became the assistant coach of R.P.I. in 1989 and head coach in 1994, remaining until 2006.