2+2=4 wrote:
One tiny bit of advice is to lean forward when you go down hill. That might help a bit if you do not already do that like many people do not. Also the problem could be you are lacking in the leg speed to go fast down hill and are more of a strength runner.
This is really helpful advice, though it's a lot harder to implement for some than for others! Sometimes it helps to think in terms of keeping the feet under the body, rather than "striding out" downhill and having the feet land way in front (which is a braking force). As 2+2=4 says, if you lean backward going downhill the feet are almost certain to land far in front of your center of gravity.
What you really want to do is emphasize turnover, not stride, on the downhill. This may be learned best by starting on a very gentle downslope, like the crown of a football field (maybe when you're doing striders). Your emphasis should be on a light, quick, relaxed backward beat of the elbows which balances a light, quick, relaxed forward swing of the knees. (The knees should lead, just as they do in sprinting--not the feet.)
You can gauge whether you've been successful on the downhill by how much momentum you carry onto the flat. If you "flow" WITH the downhill, rather than leaning back AGAINST it, you should have a lot of no-effort momentum when you get back to the flat. OTOH if you've led with your feet down the hill, you're likely to hit the bottom with little momentum, and to feel like you have to rev up again to get back to your pace.
I do like the tips above about *cresting* the hill, rather than just running hard *up* it. If you think about it, the concept is pretty simple: It's easier to run on the flat than uphill, so when you get to the top of the hill you should speed up, right? But a lot of people are only thinking about getting to the top, and then when they get there they practically stop. "Maintain [up the hill] and go [when you get to the top]" is a helpful mantra.
After a really tough uphill you're gonna feel like death for a few seconds, regardless of whether you run, jog, or just stand there. So why not run? If you switch your brain from the legs to the arms at the top of the hill, you can "shift gears" with 10-12 quick backward beats of the elbows. If the uphill is immediately followed by a downhill, this gear shift will get you right into your relaxed, efficient downhill form.
By the way, congrats on your fine uphill strength and technique! That's a tremendous weapon in a cross-country race. If you can combine that with good cresting at the top of the hill, and a smooth transition to the "weightless" downhill running that someone mentioned above, you're going to be awfully tough to beat.
[Someone asked about your height. All else being equal, I've noticed that shorter runners do *tend* to do better on uphills and taller runners *tend* to do better downhill. Plenty of exceptions, however, and I think almost anyone can improve her/his downhill technique--moving faster and using less energy to do so.]