I am about to hit 40 and have been playing tennis for 20 years. I have never been able to touch my toes. My flexibility has always been very poor. I've been thinking about trying yoga regularly after trying a 45 min yoga workout off YouTube.
I was impressed with how spent I was after just 45 min and how sore I was as well. I assume I was doing something right. I could not perform all the poses like the instructor, but I did them as best as I could.
I've also started to exercise with my daughter who runs me through her PE class workout (stretches and basic calisthenics) for about 20 mins and it is a fairly good workout.
I hope to reverse my lack of flexibility and in turn, extend my tennis playing years.
I basically do a yoga based stretching routine after all of my matches and hitting sessions. It's not a spirtual or meditative type thing, it's just a smooth progression of poses held for about 10 seconds each that leaves me feeling much less stiff, especially the morning after a match, where I will walk like Frankenstein's monster if I don't stretch.
I used to resent always failing physical education tests in grade school because I could never touch my toes..how is that a measure of my physical fitness, it's genetic!! I could do more sit ups than anyone in the school, and beat all the other measures of fitness handidly. Stupid flexibility!!
Anyway, there certainly are aspects of yoga that could be uncomfortable for someone with certain injuries, and it is no more beneficial to tennis than a well thought out modern stretching program.