Boris probably understood that grappling at a high level into ones 40s can come at the great cost of living with chronic injuries, inflammation, low T, among many other negative side effects. Sure, one can adapt their style as one gets older, but it does not guarantee that one will avoid these side effects. This is the nature of the sport... Just take a look at many of the older BJJ practitioners. They don't look too good in their 40s and 50s. They're probably dealing with chronic inflammation, injuries, and needing meds to deal with their issues, all of which have a material adverse effect on their health. One can draw a parallel with soccer. Sure, you can play pick up games into your 40s, but you will not perform as you used to and you will likely live with chronic pain if you play on an almost every day basis. For many people, transitioning into weight lifting, running, mobility, and an overall health-focused fitness regimen is preferable than pushing forward with BJJ until one is effectively crippled.,(reply>), Very true, a bitter pill to swallow but definitely makes sense.