This would be seriously confounded by both athletes who push their bodies so far that they die young for other reasons, as well as those who incur injuries and

This would be seriously confounded by both athletes who push their bodies so far that they die young for other reasons, as well as those who incur injuries and don't maintain the increased strength and bone density into old age if they make it long enough. But yes, clearly if you manage to maintain a level of strength training that is strenuous enough to promote better than baseline bone density and muscle strength, but not so strenuous as to injure yourself beyond what you can heal from, there are going to be benefits and one of them is likely to be not dying because you can't consistently stand up in old age. There was a USC running back maybe 15 years ago or so whose name I can't remember any more who somehow managed to drop a barbell loaded to 360 lbs on his throat while bench pressing, and survived. The doctors at the time mentioned that an accident like that would have killed almost anybody, but he survived because his neck musculature was so thick. But I nonetheless suspect, if you survey the average lifespan of everyone who ever makes it to the NFL versus everyone else, the NFL players are not going to come out on top.