Golf Glossary
Impact
In short
Impact is the moment in the golf swing when the clubhead touches the ball. It lasts only about half a thousandth of a second. What happens there decides the start direction, curve, height and distance of the ball flight. Everything before it in the swing serves to bring the club into that position.
Impact in golf: what happens at the moment of strike
At impact the ball meets the clubface. The contact is extremely short. On a full shot the ball stays on the face for only about half a thousandth of a second, around 0.0004 to 0.0005 seconds. During that time the ball deforms briefly and the club passes energy to it. Then the ball takes off.
The eye cannot follow this moment. Even a player who tries to “consciously hit the ball” controls nothing at impact. The movement has been set earlier. If you want a better ball flight, you therefore work on the phases before it: set-up, backswing and downswing. Impact is the result of this chain.
That makes it the most important point of the swing. Experts say the ball flight is decided at impact. The good news is that it can be measured. With a launch monitor such as TrackMan you see after each shot which values the club had at impact.
The five factors that decide the ball flight
Five factors at impact decide how the ball flies:
- Face angle: where the clubface points, left or right of the target.
- Club path: the direction in which the clubhead moves, from inside to outside or from outside to inside.
- Angle of attack: whether the club hits the ball slightly downwards or upwards.
- Dynamic loft: the angle of the clubface at impact, which affects launch angle and spin.
- Strike location on the face: in the centre, near the toe or near the heel.
For direction TrackMan gives a rule of thumb: with the driver the face angle decides about 85 per cent of the start direction and the path the remaining 15 per cent. With irons the share shifts somewhat towards the path, roughly 75 to 25 per cent as a guide. The curve of the ball comes from the difference between face and path. If the face is open to the path, the ball curves to the right, which for a right-hander is a fade or slice.
Practical example: a drive with a slight slice
A right-hander hits the driver. TrackMan shows a face angle of 2 degrees open to the target and a club path of 4 degrees to the left, meaning from outside to inside.
The start direction comes mainly from the face: about 85 per cent of 2 degrees open and 15 per cent of 4 degrees left gives a start roughly one degree right of the target. After that the difference between face and path decides. Here the face is 6 degrees more open than the path. The ball gets sidespin and curves to the right.
What does the player change? He does not necessarily have to rebuild the path. If he closes the face by 3 degrees, the difference drops to 3 degrees and the curve becomes weaker. This kind of calculation is the advantage of measured data. It shows whether the problem lies with the face, the path or both. Feel alone often does not tell you.
What impact looks like: the impact position
At address and at impact a player does not look the same. A player who has the same posture at impact as at address usually lacks dynamics in the swing. In a good iron shot you typically see:
- The hips are open towards the target, the shoulders somewhat less so.
- The hands are ahead of the clubhead. The shaft leans towards the target (shaft lean). The club hits the ball first and the ground second.
- Most of the weight rests on the lead foot.
- The head stays behind or just above the ball.
- The lowest point of the swing is ahead of the ball.
With the driver the position is different. The ball sits on a tee and the club usually hits it slightly on the way up. The low point is behind the ball. So there is no single impact position for all clubs. It depends on the club and the intended shot.
Typical faults at impact
The most common problems show up in the ball flight:
- Open face: the ball starts right or curves right. The cause is often a weak grip or a face that stays open in the downswing.
- Closed face: the ball starts left or curves strongly left, a hook for right-handers.
- Standing up: the body straightens in the downswing and the hips move towards the ball. The club hits too high or too low. This fault is called early extension.
- Flipping: the clubhead overtakes the hands and the wrists break down at impact. The result is varying distance and height.
- Toe or heel strikes: the ball loses speed and direction. In the extreme case you get a shank.
- Fat and thin shots: the low point is behind the ball instead of just in front of it. The club then hits the ground first or reaches the ball too high on the way up.
The strike pattern gives a clue. With face spray or impact stickers you see after each shot where the ball touched the face.
Practising impact
Because you cannot control impact directly, you practise the conditions that produce it. These drills have proved useful:
- Impact bag: a firm bag you hit slowly and with the full position. It shows how hands, hips and shaft should look at impact.
- Half swings: hit shots with an 8-iron up to hip height. The strike point becomes easier to control.
- A line on the ground: draw a line with spray or place a stick. Practise hitting the ground just in front of the ball.
- One target, one line: before each shot say where the ball should start. The measured data then shows whether the face matched it.
- Video: film the swing from the side and look at the position just before the ball.
Repetition in small units matters. As a guide, ten to fifteen clean repetitions per drill are enough.
Differences: impact, downswing and follow-through
Impact is a point in the swing, not a phase. Before it comes the downswing, the movement in which the club accelerates from the top of the backswing to the ball. After it come the follow-through and the finish. There the movement runs out without changing the ball flight any more.
There is also a difference between the moment of impact and the strike point. Impact describes the time, the strike point is the place on the clubface. People who talk about “impact” usually mean both. A clean strike in the centre of the face is a precondition for a good smash factor, the ratio of ball speed to clubhead speed.
Finally, impact is not the same as angle of attack or face angle. Those two values are components of impact. If you look at all factors together, you understand your ball flight best.
Try it at Golf Lounge
At Golf Lounge Resort Hamburg you can see what happens at impact in numbers. At every tee bay on the range and in the simulator rooms, TrackMan III measures the ball flight by radar, as on the pro tour. You see launch angle, ball speed, clubhead speed, carry distance and spin, among other values. V1 Pro video analysis is available as well. After each shot you can compare the measured ball flight with the one you intended.
Frequently asked questions
What is impact in golf?
Impact is the moment the clubhead touches the ball. It lasts only about half a thousandth of a second. At that moment face angle, club path, angle of attack, dynamic loft and strike location decide where and how the ball flies.
How long does impact last in golf?
On a full shot the ball stays on the clubface for around 0.0004 to 0.0005 seconds, roughly half a millisecond. That is too fast to control consciously. This is why golfers work on the phases before impact and check the result with data or video.
What is the ideal impact position?
With irons the hands are ahead of the clubhead, the hips are open towards the target, most of the weight is on the lead foot and the low point is ahead of the ball. With the driver the club hits the ball on the tee slightly on the way up. There is no single ideal position for all clubs.
What decides the direction of the ball at impact?
Mainly the face angle. With the driver it decides about 85 per cent of the start direction according to TrackMan data, and the club path the other 15 per cent. The curve of the ball comes from the difference between face and path. If the face is open to the path, a right-hander's ball curves right, and if it is closed, the ball curves left.
How can I improve my impact?
Work on grip, set-up and downswing, because they determine impact. An impact bag, half swings, face spray for the strike point and video all help. A coach with measured data shows you whether face, path or low point is the main problem.
As of: October 2026