Flexibility will not add yards. This will.

Stretching on its own will not add distance. The largest review of the research on what tracks clubhead speed found that the ability to drive force into the ground came out on top, and flexibility showed no meaningful link at all.

That surprises most people. Ask a group of club golfers why they do not hit it as far as they used to and most will land on the same answer: they are not as flexible as they were. The logic feels obvious. A bigger turn means a longer swing, and a longer swing means more speed. The best evidence we have says it does not really work like that.

What the research actually found

In 2024 a systematic review and meta-analysis published in Sports Medicine pulled together 20 studies to ask a simple question: of all the physical qualities you can measure in a golfer, which ones actually track with clubhead speed?

The answer at the top of the list was jump impulse, at a correlation of 0.68. In plain terms, jump impulse is how much force you can put into the ground over the time you are pushing against it. Upper body explosive strength and jump power came next, both at 0.58. Maximal strength, the number most people think of as "being strong", was further down at around 0.45.

Flexibility showed trivial associations that were not statistically significant.

That is worth sitting with for a second, because it inverts the usual advice. The quality most amateurs believe is holding them back showed up as one of the weakest links in the chain, and the quality most of them have never tested came out on top.

The limits are worth stating. About half the golfers in those studies were club players with single or double figure handicaps, which is useful, but very few of the studies included women. So this is a strong signal rather than a closed case.

Why flexibility still matters, just not for the reason you think

This is where it would be easy to overcorrect, and I do not want to do that, because I spend a good part of my week working on people's mobility.

Here is the distinction that makes sense of it. Mobility is permissive. It determines whether you are physically able to make a movement at all. Power is productive. It determines how much speed you generate once you can make it.

If your lead hip will not rotate, you cannot get into the positions the swing needs, and no amount of strength work fixes that. That is a real problem and it is worth solving, and it is exactly what we look for when someone cannot stop coming over the top. But once you have enough range of motion to make the movement, adding more range does not add more speed. You have solved that problem. Stretching further just gets you further past the point where it was useful.

So what does move the needle

If jump impulse is the strongest correlate we have, the practical version is the ability to put a lot of force into the ground and to keep applying it through the movement, rather than simply being strong when you are standing still.

That points at lower body power work. Loaded jumps, medicine ball throws, sprint and change of direction work if your body tolerates it, and heavy compound strength work underneath all of it to raise the ceiling. None of it is exotic and none of it needs a golf specific gimmick attached to it.

The awkward part is that this is real training. It takes months and it is uncomfortable, which is precisely why the speed stick sitting in the corner of the pro shop sells so well.

If you want a structured start this winter, Luke Northwood's Fit 4 Golf programme on Wednesday evenings in November covers four weeks of exactly this, finishing with a speed and power retest so you can see what changed.

A word on overspeed training

Speed sticks and overspeed protocols come up constantly, so let me be straight about what the evidence supports.

Here is what I can and cannot tell you. The best independent study I found, a trial of a weighted-club warm-up, showed a small but real gain of 2.6 miles per hour in clubhead speed in golfers with handicaps under three. But it was an immediate warm-up effect that had gone after the first set, ball speed did not rise significantly with it, and it was not a training result in club golfers. The larger numbers you will see quoted, whether that is seven to ten miles per hour or gains of five to ten per cent, come from manufacturers and from community testing rather than from controlled trials. They may well be right. They are simply not evidence in the way the meta-analysis above is evidence.

So I am not going to tell you overspeed training does not work, because I do not know that, and plenty of good coaches use it. What I will say is that the case for strength and power work rests on considerably firmer ground, and if you only have the time or the appetite for one thing this winter, that is where I would put it.

Where this leaves you

If you want to know whether your speed problem is a mobility problem, a power problem, or a technique problem, the honest answer is that you cannot tell by feel. Almost everyone guesses mobility, because stiffness is the thing you notice in the morning.

A performance assessment tests the physical side properly, measures what your swing is actually doing on the launch monitor, and puts the two next to each other. Sometimes the answer is that you need to move better. Quite often the answer is that you move perfectly well and you have simply never trained the quality that produces speed.

Either way you stop guessing, which is the main thing.