I think it fails on runs of varying speed, and also if you change shoes. What I did was run a measured loop at different speeds: my jogging speed, and my race speed. So I'd have a 1km at 3:30, and a 1km at 5:10 for my slow runs. I'd see what the watch said I'd done, after doing each speed 3 times each to get an average. So maybe it said I'd done 940m when I was going quick, but 910m when I was going slow. So because I know it IS 1km, I work out a ratio for each speed. Now comes the rubbish part: if I know I'm going to be doing a race, I put in the ratio I worked out at race pace, and if I'm doing a jog, I put in the ratio for my slower pace. So, yes, I have to put it in each time I want to change paces. Which is cr_p I know, but I cant see another way around it. Anyway I use it mostly at slow jog ratio for my slow runs, because I wouldnt trust it to measure intervals, I'd do those on measured courses.
One other sh_te thing. When I got it, I assumed you could put a
different ratio for different shoes, so when you change from trainers to racers, you'd change the shoes on the watch and it would change the ratio. But it seems to only change the mileage aspect for each shoe, ie how many miles each shoe has done, which is pretty lame. Who cares how many miles your shoes have done, youll know when theyre buggered or not. Or am I doing it wrong?
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