Running wonderings about speed, times and efficiency (5k)

[Mushroomwithaview]

I regularly do the same very hilly 5k route.

If I absolutely kill myself and push myself throughout the whole run, I can do it in just under 33 minutes. I'm absolutely wrecked and can feel it for 2 days.

If I jog round at a lovely, gentle pace and walk up the hills I can do it in under 36 minutes. I'm not even panting by the end.

This seems like a very small difference for the amount of effort, wouldn't you say? That's my first question.

And my second question (for someone who really knows about running) is, why is it in inefficient strategy to speed up going down the hills? I know it is because I've tested it on the same timed, hilly route many times in many ways and it's always inefficient to speed up going down the hills. I want to understand why.

[BogRollBOGOF]

The hilly 5k near me is similar effort to run 30 mins as the flat one in 28 mins (my pb is 27+ mins). The range of muscles used (particularly the calves) goes through a larger range of mobility between up hill and down hill compared to flat running. Running downhill also puts more impact through the joints and muscles as you gain have more force with gravity. It also affects your stride and you can end up "braking" yourself to maintain control.

I notice when running around other people that while I'm not the fastest downhill (I'm cautious about not going too heavy on my joints) I am pretty good at shortening my stride and speeding my cadence to blast up a hill.

[AuntieStella]

I think it's fine to speed up going down hills - I run by how it feels, so feeling the same effort for both up and down means slower up and fabulous faster down. Other people swear by pace, so more effort up and "rest" when going down.

I think it's just preference, but I did do a trail running workshop where one of the messages was very much "slow down and even walk up hills" especially in longer endurance events or tricky terrain, as you don't want to trash your legs. But for a 5k that's OK underfoot, I doubt that would be a strong consideration.

And I agree that you need to learn how to run down a hill fast - it really does sound like I have the opposite skill set to BOGOF!

[MagpiePi]

I find the same. I got my son to pace me for a parkrun and I was totally shattered. The next week I ran at my usual ‘not putting a massive amount of effort in but keeping it going’ and was only 10s slower, so IDK.
I do know that cadence makes a big difference to speed.