jandro do you own a power meter or is that some sort of calculated W value?
also aren't you smallish? (like ~140 lbs)
if you weigh 140lbs and you can rlly do 348W for 5 min then you need to enter some road road races with ~3-8 min power climbs STAT.
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"Your beauty is an aeroplane;
so high, my heart cannot bear the strain." -A.C. Jobim, Triste