It was a pretty hot topic last year and this at the World Scientific Congress of Golf (but well behind modeling of putting on a slope) now that the Sensor Edge guys have improved their technology. The Bertoli and Mucklow group both presented this data this year.
Grip Pressure: A Comparative Analysis Across Golfer Types
Liam Mucklow, Carson Hau, Jonathon Collins
The Golf Lab, PGA of Canada
A comparative study of grip pressure differences between Amateur and Tour
Golfers
Davide Bertoli
DB Golf Center
This has been pretty well known for a while but now the measurement technology has improved a lot so you don't have to drag a bunch of different caliber of golfers to your lab and you can go to them to collect data. In 1979 Budney published data that has been essentially unchanged since then: Budney D "
Measuring Grip Pressure During the Golf Swing",
Research Quarterly. Back in 2006 Schmidt had to entice all different types of players to make their way to the middle of nowhere England to publish her PhD thesis "
Measurement of grip force and evaluation of its role in a golf shot". The Japanese group also struggled with this in 2006. S. Koike "
An instrumented grip handle for golf clubs to measure forces and moments exerted by each hand during the swing motion". Ramey had a better time of it due to his location near a lot of high level players. Broker, J. and Ramey, M. (2008). "
Understanding golf club control through grip pressure measurement"
Other primary sources that have given a good foundation to work from can be found in:
Komi ER, Roberts JR, Rothberg SJ. Measurement and analysis of grip force during a golf shot. Proceedings of the Institution of Mechanical Engineers, Part P: Journal of Sports Engineering and Technology. 2008;222(1):23-35. doi:10.1243/17543371JSET9
Langlais, S. M., & Broker, J. P. (2014). Grip pressure distributions and associated variability in golf: a two-club comparison.
Sports Biomechanics,
13(2), 109122.
https://doi.org/10.1080/14763141.2013.878377Holland S, Dickey J, Ferreira L, Lalone E. Investigating the grip forces exerted by individuals with and without hand arthritis while swinging a golf club with the use of a new wearable sensor technology. Proceedings of the Institution of Mechanical Engineers, Part P: Journal of Sports Engineering and Technology. 2020;234(3):205-216. doi:10.1177/1754337120923838
The basics are that the pros have a much stronger baseline grip than ams, they grip the club much tighter in their lead hand and have much less variability in grip pressure throughout the swing than ams, professionals have a dip in their grip pressure in the early downswing not seen by even high level ams, the ratio between lead and trail hand pressure stays similar throughout the swing. High handicappers have far too much trail hand pressure compared to their lead hand pressure and the highest handicappers have a stronger trail hand grip than lead hand and the only group to show this, they grip it light at address and just continually increase the pressure throughout the swing, they have much less total grip strength.
Its actually a pretty difficult thing to measure when you consider "grip" is solely the radial force on the grip and you have to be able to tease out the hand couple, moment of the hand force, and total torque.