Complex sentence: His increased attention to training paid quick dividends, as he won a mile race in 4:09.9 on 30 December, then in 1951 at the Penn Relays, Bannister broke away from the pack with a 56.7 final lap, finishing in 4:08.3.
Split into simpler sentences: His increased attention to training paid quick dividends, as he won a mile race in 4:09.9 on 30 December. Then in 1951 at the Penn Relays, Bannister broke away from the pack with a 56.7 final lap, finishing in 4:08.3.