Why going downhill is hard work

On Saturday I took the train out to Katoomba, in the Blue Mountains. The train journey certainly gave me a feel for just how vast Sydney is. An hour out of central station, and one is still in the Sydney suburbs. But suddenly the end of the city comes abruptly – the train is suddenly amongst the trees and starts climbing. Another hour gets it to Katoomba, a small town perched on top of precipitous sandstone cliffs.

I quickly got the impression that the way many (most?) tourists see the Blue Mountains is on a coach tour. The coach pulls up in the vast carpark at Echo Point, the tourists pile out with their cameras, take lots of photos of ‘The Three Sisters’, grab an overpriced icecream, then pile back into the coach to go to their next viewpoint, wherever that is. Certainly Echo Point has a feel of an international airport about it.

However, escape the crowds, and it becomes rather more pleasant. The way I did that was to head to the bottom of the cliffs. There’s three ways of doing this. 1. Take the ‘railway’ (I assume this is a funicular – I didn’t get a look at it) or the cable car down. 2. Walk. 3. Jump.  I chose option two. That involved heading down the ‘Giant Staircase’ – about nine hundred steps in total down 250 metres or so of nearly sheer sandstone cliff.

One of the surprising experiences going down this number of steps is just how hard going it is. Near the bottom, my legs were burning – rather like having done a REV class in the gym. What’s happening is that I’m exercising muscles that don’t usually get a good workout, and it hurts. In physics terms, I need to provide a force against gravity to slow me down as I descent. The force of gravity alone would cause an acceleration downwards;  in order  to descend at a constant speed I need a force that balances this (Newton’s first law), and that comes from under-used muscle groups within my legs. After several minutes of this, it hurts.

Incidentally, in energy terms this force is not supplying energy to you, unlike the reverse case where it takes energy to climb the steps back up. That’s because the force is in the opposite direction to your movement – therefore it doesn’t do work on you (transfer energy to you). In fact, it is doing the opposite – your legs are absorbing the potential energy lost as you head downwards. No wonder they are burning at the bottom.

Once at the bottom, it was a lovely walk through the bush (though I did get a little worried about what zero- or eight-legged nasties might be lurking in the undergrowth). I went back up a different route – past many lilttle waterfalls. I lost count at 1200 steps. And at 1000 m altitude, or thereabouts at the top, it’s quite an effort for a near-sea-level-dweller like myself.


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