Update introduction.md

Co-authored-by: Anastasios Chatzialexiou <[email protected]>

Author: ErikSchierboom

exercises/split-second-stopwatch/introduction.md

@@ -1,5 +1,5 @@
 # Introduction
 
 As an amateur runner, you've never really felt the need to track your time precisely.
-However, having just enrolled in a local running team, you're now being given precise practice schedules, which are tuned to the second.
+However, having just enrolled in a local running team, you're now following precisely timed training sessions, each one tuned to the second.
 You've therefore decided you need to purchase the _split-second stopwatch_, a basic but very precise stopwatch.