Will cross country kill my speed?

Those are good 200m & 400m times. XC season is over half complete. Is head XC coach the same as head T&F coach? Opinions differ. Most on here will tell you XC won't hurt your speed. You will find out one way or another.

No.

Does your coach prescribe hill repeats, strides, 200s? You ever do VO2 max workouts and not just easy/tempo? If so, you'll be fine. You won't be trained for 400, but you should be able to transition back well enough.

We had a girl that was a 300m hurdler that came out for xc. The next track season she ran 42.x and was state champion. Did not hurt her speed.

It is not true. What is true is that you lose what you don't train. Although, at your age, your speed will come back quickly for indoor. But, to be safe, try to work in a session once a week or so where you work on your top end speed. You should discuss with your coach.

If you do okay in XC, it may well be that 800m is going to be your event in the next few years.

The XC and track coach are pretty much the same. Guess I'll just have to wait and see.

We routinely do strides at the end of each run, but our workouts are practically never under 800m. We do a lot of hill repeats though, not particularly fast but lots of reps at 5k race pace. Is it possible for my 400 time to improve from XC?

I run a 20:53 5k as of now, is that 800m worthy in the future?

The absolute advice some of the other posters are giving you is too strong. The truth is maybe. Those times are so good, I would hate to see you go backwards as a sprinter. Do you have another fall activity you could do next fall like soccer? Is female LaCrosse a spring or fall high school sport? If the choice is XC or sit at home on the couch, okay participate in XC but don't try to be a member of 1000 mile club next summer.

So I hate to tell you, but those aren’t actually good enough times for you to be worried that XC will be ruining them. If you do XC you will maintain the 400 time imo, and it will make you a lot better at events like the 800. If you do XC, it could take you to running a 54 400 next year and a low 2:xx 800, and meds most races, compared to running just running the 400 and usually getting almost last. I went from a 61 to a 56 400 with no speed training just from the strength XC gave me, and if you lifted too, and did more sprint work in track, you could be very competitive in 800 and 400.

This is a girl so these times are very good, I would avoid xc just to be on the safe side.

Ahh, I see, forget everything I said, I am an idiot. Don’t do XC, do the 400!

There are examples of great 400-meter runners that had run XC in high school. Monique Henderson is a good example.

You will change characteristics of your fast twitch fibers that will revert back as your track season goes on. In the meantime, you will have managed fitness, have endurance especially for that last 15 seconds of your 400. You will have better ankle strength and flexibility, stronger connective tissue, and greater bone density for injury prevention.

shes not in the top 100 freshman girls for the 400 (need to be under 58). So it's not like she is one of the best most naturally talented

Kerron Clement was the top XC runner for his team in HS and regularly ran in the low 17s for 5k. He didn't just run XC, he was competitive. He was also the best 110 and 300 hurdler in the nation during the spring. 2 years out of high school and he set the world indoor record in the 400. He was a 2-time Olympic gold medalist and 4-time World champion. Cross country did not hurt his speed.

The key is that you still need to do some true speed work during your XC season. Even 8 x 50 at full speed just once a week will continue to build your speed even as you put in your distance work.

athing mu ran everything from 200m up to 5000m/xc in hs and has done ok for herself in the 400/800/1500 since moving on to college and beyond

raw/basic speed (essentially 200m time) is important for runners of all distances, as it essentially functions as a ceiling which all other times over every distance will hang below

keep in mind, the most elite hs female xc runners will tend to have 26/58 200/400 speed

No. hs women are not running 26s and 58s and winning state xc or even top 10 in NXN thats absurd. I doubt that anyone of the top 10 at nxn could run under 27

You would be very much mistaken then. Most of the girls at the top level have great speed in comparison to the guys. 7/10 in the top 10 could probably break 60 and the remaining 3 could probably run 56-57. Probably around half under 27.

The science is clear here. It will hurt your 200 and 400m race time, as your fast twitch fibers gets more aerobically.

The real question is, how long it takes after XC to bring you back to the same level (or better) at your short distances. And how much time and potential you lose., because you interfere whith your goal to become a good 200/400m runner.

You're too young to be worrying about stuff like this. I doubt they have you running super high mileage. The added strength should only help you in the winter/spring. Maybe you find out you're good at cross too.