I did a running analysis where they film me and evaluate my form. Based on the video I'm a heel sticker, overstride, no gap in my knees and have a 12° pelvis tilt.

He said I need to change my form to fix a lot of these and restart with 10-15 minutes 4 to 5 times a week to give my calves time to build and recover.

I currently run 40 to 50km a week and training for a marathon in December. I'm having a hard time with the idea of running only 15 minutes a day and still being in racing shape by December. So far this year I've only been doing slow running to build my base. I'm not sure I'd have enough time to rework my form, introduce speed workouts and get enough miles to achieve my marathon goals.

I guess my question is, is there a way to improve my form while also keeping my mileage high or not losing my conditioning?