Very icy outside again so confined to the turbo again. Rode a 3D course I produced earlier in the year for exactly this eventuality, it's called UKRoute03 and is a course I produced from GPS data I collected on the usual L3 road route so the data comparisons were interesting. It was a good workout, the turbo is harder than the road in feel anyway, no short downhill respites, got to keep the pedals turning. Came out as a TSS score of 136 which was ideal (without the warmup score which took it over 140). Looks like these L3 rides come out at about 1 TSS point per minute which is a good guide for planning workout length, IF looks to be pretty much the same on the road as the turbo, as it should be. So, good effort, hard work but better by far than doing nothing because of the weather.