The Moment of Impact

The Moment of Impact, explained by The R&A's Director - Research and Testing, Dr Steve Otto.

ImpactWhat happens when a driver head strikes a golf ball?

The amount of time a ball is in contact with the club face depends on factors such as swing speed and swing plane, but, if we take a hard hitting Tour professional with a swing speed of, say, 120mph, the ball will be in contact with the face for about half of a thousandth of a second.

So what happens in that time?

During that contact time, the ball can be compressed, or squashed if you like, by up to 25%, and it will accelerate from zero miles per hour to around 1.5 times the speed of the club – so 180 mph in the case of our Tour pro. This represents an enormous acceleration and the force on the ball is around 6000 Newtons. The direction and spin will all be determined in that split second and these are the factors which, ultimately, determine the fate of the shot.

And what happens once it’s in the air?

A well-struck drive will remain in the air for upwards of 6.5 seconds, rotating roughly once every yard of its flight. The ball then strikes the turf and rolls to its final resting place awaiting the next stage of its journey. The amount of roll doesn’t just depend on the ground conditions. It is also influenced by the launch angle and spin with which the ball leaves the club.

Does it matter what driver and ball the player uses?

If a player is using equipment which has been properly fitted to their physique, swing and ability, this can have a positive effect on their game and can help them to maximise their potential. Taking lessons and spending time to do lots of good, old-fashioned practice can also make a big difference.

Most importantly, all equipment must conform to the specifications set out in Appendices II and III of the Rules of Golf!


Throughout the year, we take the chance to question our Research, Testing and Equipment Standards Department about a piece of technology from golf’s past and present, be it a persimmon driver, a pitching wedge or a peripherally-weighted putter.

If you would like to ask a question of your own, write in to

Before writing in, why not look in the Equipment in Focus archive to see if your question has already been answered?