I had a bout of neck pain and numbness in the left arm extending to the hand (cervical radiculopathy) last year after several sessions of forced neck extension riding a tribike on the computrainer. I was trying to get lower and stretch so that I could see the road ahead of me. Bad idea. Turns out I had a disc bulge and foraminal stenosis. I opted for physical therapy with therapist who specialized in spine problems. She is also a pilates instructor. Several things helped including pilates exercise, use of an inflateable traction device at home and local therapy with heat. Also, she had me buy a posture shirt which improved my posture quite a bit and also helped in solving the problem. So far, no recurrent problem though I have given up on getting really low on the tribike. Good luck.