Complex sentence: Resolving to carry on in football, he entered study as a physiotherapist and became Arsenal's first team trainer under Herbert Chapman in 1927 (whilst still younger than many of the players on the pitch).
Split into simpler sentences: Resolving to carry on in football, he joined Arsenal's coaching staff and entered study as a physiotherapist. He became Arsenal's first team trainer under Herbert Chapman in 1927 (whilst still younger than many of the players on the pitch).