I think the basic answer for us geezers is to refine our gear and approach to preparedness.

Counter diminishing muscle strength by reducing the need for strength and also by using strength multipliers and substitutes.

Substitute titanium, ceramic, and plastic for stainless or other metals, for example. Use tools that incorporate levers and ratchets instead of brute grip or other strength. Borrow the power of gravity, electricity, chemical reaction, and even gunpowder where possible in place of muscles.

Focus on wily tactics and "unfair" advantages; "fight dirty." Think of how to "take advantage" of others. Think poaching rather than hunting, ambush rather than chase, and sucker punches rather than fair fights. Study camoflague and hiding in plain sight rather than being obviously strong and intimidating.

Think in terms multiple fighting retreats rather than set piece battles; make pursuit of you cost your enemies just enough to persuade them to leave you alone. Study guerilla tactics and asymmetrical warfare techniques for making your territory something others would just as soon leave alone because of multiple, overlapping, and ever-changing layers of booby traps.

Eliminate reliance on one cache, resource, or place of retreat, and instead pre-position multiple resources conceding that many will become at least temporarily unavailable. Increase focus on the ultra-portable in preference over the ultra-comfortable.

And stuff like that.