Every training run should have an objective ...

... and the objective of my run today was to do 10 miles at my aspirational 10-in-10 pace on slightly sluggish and over-used legs. Running on legs that would prefer to be resting is something I expect to be doing rather a lot in May.

Leon blogged earlier about adaptation. Well, adaptation is my favourite physiological process too. It's taken me from being barely able to move for days after my first marathon to being able to complete two marathons on consecutive days then spend the next day hill-walking and scrambling. It's made me such a fuel-efficient runner that I can maintain my weight easily even at 70mpw without blowing the food-budget. It's made running 10 marathons in 10 days look feasible.

What would you expect to happen to a recreational athlete if they ran a marathon every day for 10 days? Conventional wisdom suggests that they'd develop progressive muscle glycogen depletion, accumulate microscopic muscle damage, and produce increasing amounts of cortisol and other stress hormones. A more holistic assessment would consider the complex neuromuscular, psychological, immunological and endocrine changes that take place with intense prolonged exercise. Either way, the conclusion would be that the athlete's performance would decline and they would succumb to physical and mental fatigue, illness or injury.

What actually happens?

http://www.brathaychallenge.co.uk/brathay-10-in-10-marathon-times-2008.asp

Those are last year's participants' times. Everyone finished apart from Susan Adams, who fractured her foot in the 6th race (and whom I'm delighted to see will be back in 2009). Most of the runners ran remarkably consistently over the 10 days, without the progressive fading-out that might be predicted. Some got faster as the days went on. One man ran a PB - that's a career PB, not just a 10-in-10 PB - on the seventh marathon.

There are no short-cuts to that sort of performance, and you can't do it on bloody-mindedness alone. It's the result of years of running experience.

Back to today. My legs were feeling the effects of the run I did yesterday - 9 miles at 9.30mm pace, then a fast quarter-mile to finish - and my calves hadn't forgotten the 20 miles of hill-walking at the weekend. Leon and I had decided yesterday that we'd do 10 miles together this afternoon between my work sessions, and there was no reason to abandon that plan.

I was very pleased with an average pace of 9.45mm for 10.5 miles on an undulating route, and could have gone on longer had I not needed to go back to work.

I'm hoping that the rhubarb crumble and custard we had for dinner tonight will have worked its magic by tomorrow :o)