To the poster of the Arcadia video. Gracias. I see one glaring
potential issue with Mr. Mantz, is that left arm, looks like Belayneh Dinsamos' minus the full clock like motion of the arm, you should break that habit and get your form more bi-laterally. Form will serve you better in
the sprint/finishes. Anyway, technically your body's propulsion should be more locomotive like, your arms should be like the arms of the wheel on a locomotive. At this stage in your running career, habits could be broken, just remember when your out doing it. Best way to break the habit, seriously is to find a very steep hill about 440 yards, do fifty sprints up (arms like a locomotive), jog back down, drop your arms. Notice the locomotive like action of your arms should sync back together.
But since you're a junior you might want to try this before you graduate high school, just before the track season (Jan is a good time). Plot and do a start stop marathon on the road, just found my old route map. Good thing it was a cloudy day.
During the stops like traffic lights you can stretch, but stop the watch when you go in for a drink at a gas station or better yet have a friend follow you. With that said, if you can do under 2:06.00 (yes two hours and six minutes) for a full marathon adding about 220yards for a margin of error. We must also to remember to 'run for God'. Have fun.