Final answer:
In sports such as badminton and tennis, stepping on or over the baseline before striking the ball is typically a fault, but a player's feet moving over the line on a volley follow-through, after the ball has been hit, is generally not a fault. In volleyball, stepping over the service line during a serve is a fault.
Step-by-step explanation:
The question pertains to the rules of a sport where a player must not step over a line during a volley follow through. While the specific sport is not mentioned, this scenario often applies to sports such as badminton, tennis, or volleyball. In general, for sports like badminton and tennis, a player commits a fault if their foot touches the baseline or the court before striking the shuttlecock (badminton) or the ball (tennis).
However, if the follow-through, which takes place after the shuttlecock or ball has been struck, results in the foot stepping over the line, it is usually not considered a fault. The rules can differ between sports and it is essential to consult the specific sport's rulebook for accurate information. In volleyball, stepping on or over the service line on a serve is considered a fault. Similarly, crossing the centerline during play can constitute a fault depending on the situation.