I have been following a B210k program, now on week 4. On Monday ran for just under an hour and felt great. Went out this morning, perfect running conditions but after 10 minutes felt awful, legs like lead and breathing heavily. Decided best to return home. Normally manage 3/4 runs a week with no problem so this was bit of a shock. Yesterday I spent all day working in the garden - digging over the vegetable patch and cutting back some trees, surely this would not cause the lack of energy today. I cannot decide whether to try again later today or rest up and have another go tomorrow.