Too much weight training?

Age/height/weight? Current running volume?

Those numbers might influence one's answer to your question.

But taking a stab anyway, at first glance it sounds to me like too much if you're looking to be a better runner. I think some weight training is a good idea, but I'm not convinced even half that volume would be necessary if your primary goal is to be a better runner. Perhaps sprinters would be an exception but even then, that lifting volume would seem like a lot.

Now if you are trying to look better - not saying you look bad - then you might be spot on with that weight training volume. Aesthetics is not a bad goal, but it can sometimes be at odds with better running.

15 5'10 126

Only 30-35 mpw right now, hoping to build to 50-60 by March

Sorry, forgot to change username above

I don't think it's a good idea. Lift 3 days a week for 30-45 minutes doing basic movements like push ups and push up variations, inverted rows or pull ups, squats, dead lift variations, step ups and diagonal lunges. These movements are simple and more functional than just isolating muscles.

At your age, it won't take that much weight training to add muscle. My guess (depending on genetics, or course) is you will add a lot of muscle naturally and a little weight training will accelerate that. I would be careful if running is your primary goal, however. Watch what you eat (and at your age you have plenty of room to cheat) and watch your weight on a regular basis as you embark on a weight training program.

lifting weights, or doing general resistance training is not about putting on weight/muscle. it is about increasing the potential of the muscle. if it can be done without weight gain then that is ALWAYS better for a runner. ALWAYS.

your weight will increase naturally over the next 10 years, but as a runner you should NEVER try to increase your weight. look only to increase your muscular strength and if additional muscle comes with it then so be it.

as for the actual training, i can't recommend a 45 minute session of lifting. instead, you want to lift for about 3-5 minutes, then run for 5-8 minutes, then repeat until you are don't with your lifts. 1-2 sets at a time and 1-2 exercises with that 3-5 minutes is enough.

focus on the calves, quads, and glutes' eccentric strength. focus on the torso's isometric strength.

keep your stretching to the bare minimum, only such that your symmetrical again if one legs' musculature is tighter than the other leg.

most importantly, intend on winning.

Teh answers to your questions really depend and require you to be more specific about your preferences and goals. Are you trying to bulk up but not too much to look good, to be fit, to improve your running, to prevent injury and maintain muscle balance or some combination of those?

Lift heavy weight big muscle groups. Squats, front squat, lunges, deadlifts, bench, flys, rows, lat pulls, pullups, etc. Add in some plyos (box jumps, depth jumps, hops, bounding, etc.) 4-6 exercises 2-3 times a week. This shouldn't take you more than 45 minutes MAX, ideally closer to 30 minutes since you aren't running that much and you could use some more time to do so.

Also note, you will not bulk up. Whoever said it's easy for a kid your age to gain weight is wrong. Ask every freshman/sophomore high school football player. They're lifting 4-5 times a week and eating until they want to puke, and can barely gain weight.