Striving for a supercharged golf swing could play havoc with your back, according to US doctors.
The modern "X-factor" swing favoured by many professionals may hit balls harder and further but it can also put extra strain on the spine, the Barrow Neurological Institute experts say.
They look at the example of Tiger Woods in their research, which is published in the Journal of Neurosurgery: Spine.
The 43-year-old player recently made a comeback after serious back issues.
Swinging the golf club at measured speeds of 129mph at the April 2018 Master's Tournament, Tiger Woods appears to be back to physical fitness.
And he has said that he now has a greater understanding of what he "can and can't do" this season.
"A lot of it has been training, trying to get stronger," he said.
Big swing
An X-factor golf swing tries to get maximum rotation of the player's shoulders relative to their hips at the top of the backswing.
This big rotation creates wound-up potential energy - the X-factor - but Dr Corey Walker, Dr Juan Uribe and Dr Randall Porter, from Barrow, say it may come at a cost, twisting the lumbar spine.
The spinal surgeons have been studying how the golf swing of present-day professionals, including Tiger Woods, differs from those of golf veterans, such as Jack Nicklaus and Ben Hogan.
They say players' physiques and techniques have changed significantly over recent decades.
Modern players are more muscular and have more powerful downswings and this can put increased force on the spinal disc and facet joints, they believe.
And over time, it can result in a damaging process that the authors call "repetitive traumatic discopathy" (RTD).