I did my race committee duty at our Laser frostbite fleet yesterday. It was a challenging day for some of the sailors with the wind gusting over 20 knots at times. In the changing room afterwards one of the sailors complained to me he had been suffering from "thumb cramps".
I sympathized because I've had that experience myself. Or at least I think that he was talking about the same thing. Sometimes towards the end of a hard day of Laser sailing my hands and forearms cramp up. The worst symptom is that my thumb and fingers freeze up so I can't open them. So there I am happily sailing along and then when I want to tack I can't let go of the tiller. Occasionally it's so bad that I actually have to use my other hand to prize my fingers and thumbs off the tiller. Not exactly the most efficient way to tack.
I think it's usually caused (at least in my case) by holding the sheet too tight. I use a fairly thin line for my Laser mainsheet and, even with a ratchet block, it requires a fair amount of grip tension to hold it when beating. I don't like to use cleats because it prevents me from sheeting out quickly in gusts. Strangely enough though, the cramps usually hit me first in the hand holding the tiller but I can't believe that my light, relaxed grip on the tiller is causing the problem.
It happened to me once at a Laser regatta at Marsh Creek Sailing Club. Going into the last race I was tied for first place. Just had to beat one guy and I would win my first Laser regatta ever. It was cold and windy and my arms were getting tired. And then the cramps hit me just at the start of the last race and that was enough to lose me the race and the regatta. At the time I wondered how much of the cause was psychological. Did I choke?
After a few such incidents I decided to do something about it. Classic ways of avoiding cramps are to stay well hydrated and to ensure that your potassium level is high enough. So I try and remember to eat a banana before sailing and to drink plenty of water between races.
I also wondered if I was holding the sheet too tight. So when practicing I try to consciously relax my grip until just tight enough to prevent the sheet slipping. But in the excitement of the race I am sure I forget to relax.
And I reasoned that if my muscles were stronger they wouldn't be worked so hard that they would cramp. So I started exercises for my forearms -- curls and extensions of the wrist using light dumbbells. And I bought some devices to exercise my grip.
Over the years these methods seemed to have reduced my tendency to experience the dreaded thumb cramps. But not entirely eliminated them.
I just googled "thumb cramps". 95% of the results were related to cramps caused by repetitive use of devices such as play consoles and cell phones. Too much text messaging can cause thumb cramps, apparently. This seems to me to be a totally different kind of action from tightly gripping a sheet but, hey, I guess cell phone usage may be as strenuous a workout as Laser sailing if you overdo it.
I found one report of thumb cramps by a kayaker and a few by musicians, violinists, guitarists etc. These sound as if they may be similar to what sailors experience. Gripping something hard, for hours at a time maybe, while involved in doing an activity that engages you passionately so you forget how much you are working your muscles.
Today I came across a blog by a sailor in the UK who has just purchased a new gizmo called a Powerball to exercise his arms and hands. It has a gyroscope inside and claims to be the latest wonder device for building strength in these areas.
Maybe I'll put it on my Christmas list. It does say it is the ideal gift for the man who has everything.