10 km race under 35 min

[larryecuador]

Hi,

I went out for a 16 km run today at a nice slow pace.

I was wearing my vibram 5 finger shoes and stepped on a pointy rock on a track that I was running on after about 7km. I struggled on for a bit but then stopped at about 10km as it was too sore. I fell asleep on a rock for a good half hour in the warm evening Stockholm sun and then started to run back.

This is the strange bit:

I started to run back and the pain in my foot slowly subsided but my heart rate quickly shot up. I looked down at my watch and saw my heart rate at 194 and I was running at a very slow 5:30 pace. I did not feel that tired and although it came down from that high point it was hovering around 160 bpm and I was not going that fast.

Heart Rate

Avg 124 Max 149 (first 10 km) 5:17 per km

Avg 159 Max 194 (last 6km after rest) 5:25 per km

Is this just a weird thing with my garmin 305 watch?

Thanks for your help,
laurence