I’m not old at all but had some crap running form. Aka, a weak core. It caused me to bend at the waist too much running.
This led to other run form issues and nearly an injury.
I did the work similar to that GCN corr video twice a week for two months and the difference was awesome.
Now in off days from the bike I do a basic strength routine with core.
So I can advocate for those exercises. It also helped me hold my aero position on the road bike much longer. Now I can do decently long threshold sets in it.