I am definitely not a weightlifter or a bodybuilder but I do spend some supplemental time in the gym lifting weights to make sure I am within the healthy muscle mass range because I have a fast metabolism and burn off weight easily.
I find that once you get to a certain weight, just losing overall mass and adding miles can only get you so far. I mean sure, losing weight will get almost anybody under 7:00 for a mile but 5:00 or even 5:30-6 will probably require some proper power/speed/anaerobic work which requires physical strength (I’m talking about females). At some point, at least if you plan on reaching your potential, you are going to need to focus on optimising composition instead of just focusing on getting down to racing weight. My weight is already pretty damn low (99lbs at 5’0), losing either muscle OR body fat would probably harm my performance at this point.
Okay, so ... numbers. I don’t know my squat max because the squat rack at my local gym is broken /: but I do overhead squats weight a barbell at home, I normally focus on doing as many as possible with good form so probably about 90ish of these broken up into sets of 15 - squatting about 30% of my bodyweight per rep, this is obviously easy.
I can bench 75% of my body weight and deadlift 125% of my bodyweight so I have basic strength. Would this be enough PHYSICAL strength to break 5 minutes in the mile PROVIDING I built up the appropriate endurance? I’m currently running a 5:45 mile on 35 mpw + intervals, I have also done some pure speed work.