In "healthspan" we learn that correct lifestyles including nutrition and regular exercise can add years to a person's life, but more importantly, maintain reasonable health and functionality well into their later years.
The newly coined term (American Council on Exercise) "Strengthspan" refers more specifically to the importance of building and maintaining physical strength if one wants to extend their lifespan and their functionality. In short, this means that while any sort of exercise would be beneficial, one must include regular strength training if one wants to derive the full benefits of an extended life.
There is no substitute for the good old barbells and dumbbells.
Peer reviewed studies have shown that there is a relationship between strength and an extended "healthspan" as well as an extended functional life.