Complex sentence: Her first-ever competitive races with her team, she skated 53.10 at the 500 m and 2:53.8 at the 1500 m. In upcoming years, she improved steadily while her training capabilities were set to ever higher levels.
Split into simpler sentences: Her first-ever competitive races with her team, she skated 53.10 at the 500m and 2:53.80 in the 1500m. In following years, she improved steadily while her training capabilities were set to ever higher levels.