yhwh wrote:
If you are running on grass or trails, that is better.
You are in HS, and I don't think any run should be over 1 hour in length.
In fact, in college our runs were only 1 hour (10 miles by then).
Do a little speed work, or bound up some hills.
I don't think HS is the time to focus on 10k or half marathon or marathon, and that is what LRC caters to.
Everyone's free to post here, but I respectfully suggest ignoring this guy's advice. He believes runners should start with short races such as you posted PRs for and 'move up' later. This is or is not a wise principle depending on who the athlete is - for example, slow-twitch / fast-twitch ratio and aerobic vs anaerobic systems. It is, however, very common advice - in the United States and, with the possible exception of Canada, nowhere else. There are 2 reasons for this:
1. IF (a big if) you run for a school, or various schools, as much as possible - which is to say, any time you're enrolled in one and have eligibility - it is what you must do. You won't have the option of running longer than 5k for a few years, then 10k for several more. By the time you really have choice of what events to run, you will be much older than now. Of course, you can beat the system bu not attending any college with sports programs or no college at all. It's also pretty darn easy to avoid high school running even when in high school. This was common when I was your age and races 10k through marathon were loaded with 15-17 year olds.
2. It is what the poster himself did. I don't know him but am extremely confident saying that he ran for his school's teams. He thought that if you wished to run competitively, that is what you are supposed to do. Of course the posters on the message board are going to suggest not running anything longer than 5k prior to college (and not much longer even then). What they were told to do; itself what they did; it's what they believe you should do.
Really, #2 is not an independent justification for this particular - or any given - poster to recommend the gradual 'moving up' that is close to universal in the US and unheard of in Kenya. It is really a spin-off of #1. The real reason high schoolers don't run marathons, half, etc. is because schools don't offer such as an official school-sanctioned sport. American colleges don't either. If they did, nobody would consider it 'wrong' to run longer races at age 20. If your high school sponsored and chaperoned road racing, and so did every other school during the last few decades, it would considered OK at 15. And, by the way, you wouldn't get posts telling you not to do it.
OK, on to the question at hand. This topic has already been hashed out right here on the Board:
https://www.letsrun.com/forum/flat_read.php?thread=1363335