Looking for some guidance about my exercise routine. I’m in my late 50s, have run 4 times a week since my 20s, no injuries up to half marathon distance. I’ve always maintained weight through this and fitness. But recently I’ve noticed I’m losing muscle and getting flabby (although no change in weight). So I think the time has come by I introduce some weight training but I don’t know how to balance this with running. I can’t fit in any more than 4 fitness sessions a week and I need that to run my 20 miles a week. Anyone got any suggestions about how to alter my routine?