The forehand runaround is a court-position trade, not a preference

What the movement actually costs

Moving to the left as a right-handed player to strike a forehand places the body well outside the centre of the court. Every metre travelled in that direction is a metre that must be recovered before the next shot arrives, and the clock is already running. The opponent, seeing the movement, has a large and obvious target on the vacated side that requires no particular precision to exploit.

The trade is therefore explicit: one shot struck from the preferred wing in exchange for a court that is temporarily indefensible. Players who make the movement without acknowledging that cost lose points they had every opportunity to win.

When the trade is worth making

The runaround is justified when the resulting forehand is likely to end the point or force a defensive reply that cannot be directed. That usually requires a ball landing short, sitting at a comfortable height, and arriving with enough time to complete the movement in balance. If any of those conditions is absent, the player arrives late, strikes without full weight transfer and produces a shot that does not threaten.

A neutral forehand struck from an exposed position is strictly worse than a solid backhand struck from the middle of the court. The judgement therefore has to be made in the first fraction of a second after the opponent's contact, before the movement begins.

Why the shot direction matters so much

A forehand struck from the backhand corner most naturally travels crosscourt, which is the shortest path and the safest margin. That direction, however, leaves the opponent able to reply into the open court with the entire width available to him. Striking down the line covers the vacated space but travels over the higher part of the net into the shorter part of the court.

Players therefore accept a smaller margin on the shot precisely when they are least well positioned to recover from a miss. The inside-out and inside-in decision is consequently one of the most consequential shot choices in the modern baseline game.

How opponents defend against it

The standard counter is to play behind the movement, sending the ball back to the side the player has just left rather than to the open court. This is difficult because it requires disguising the intention until after the opponent has committed his weight in the other direction. It is also risky, since a ball struck to the side a player is leaving becomes an easy forehand if the movement is read incorrectly.

Players who can execute it force their opponent to stop guessing, which restores the backhand to the rally and reduces the aggression available. The exchange is a genuine cat-and-mouse pattern and it recurs several times in most competitive baseline rallies.

Why the pattern shapes whole styles of play

Some players organise their entire baseline game around creating conditions for the runaround, hitting shorter crosscourt balls to invite the reply they want. Others build around never allowing it, directing almost everything deep to the backhand corner with enough pace to prevent the step around. That contest is often the real substance of a baseline exchange, even though it takes place in the positioning rather than in the strokes.

Watching which player is dictating where the other stands is a more reliable guide to the state of a rally than counting winners. The stroke everyone remembers is usually the final expression of a positional argument that was settled several shots earlier.