i have had this problem for years, i have tried everything to get rid of it, supplements, physio, stretching, excerises, splints, massage, bowen therapy, acupuncture and now chiropractic. Physio and doing hand specific excercise especially tennis elbow excercises really work but who has an hour everday to do that. acupuncture worked a bit but not enough for the money, bowen and massage the same. now i am going to the chiropracter and he says it is a pinched nerve in the neck and after 20 treatments i should be cured, im on treatment #6 and theres progress, so im hopefull. I find going to the gym and doing a whole body workout really really helps, you can actually strengthen your tendons by working out. i wear a carpal tunnel brace to bed every night to prevent me from curling my wrist all not which i do automatically. i believe the diet thing for sure because there was a time i was serious about working out and cut out allot of salt and drank tons of water and my writs got allot better but i love salt so that plan never works. i think one of the hugest thing you can do to alleviate this problem is to get some of the biggest heaviest stainless steel grips you can get and fairly heavy iron machines, the big grips absorb allot of vibration, counter the back weight of a coil machine and provide a more relaxed grip, i use the biggest grips i can find which ar 1" 1/2 grips from cam supply. i have never heard about the gastron technique but it looks like its worth a try, it looks like a method of killing nerves a kick boxer told me about, he would run a rolling pin over his shins everynight so he could kick people harder without feeling it