Ribble Valley 10k - Week 3 of 8

M Rest
T 9.5 miles HA (6:33mm), 5 miles (7:50mm)
W 11 miles including 30 minute Tempo (5:47mm), 9 miles (6:36mm), 4.5 miles (6:43mm)
T 8 miles HA (6:44mm), 5.5 miles (7:25mm)
F 12 miles Fartlek (5:46mm), 5 miles (7:15mm)
S 8 miles HA (6:46mm), 5.5 miles (7:24mm)
S 18 miles (5:50mm)

Total 103 miles (6:31mm)
Aerobic efficiency 986 beats per mile Vs 1024 beats per mile
Weight 142.8lbs Vs 143.9lbs
Body Fat 10.6% (15.14lbs) Vs 10.65% (15.32lbs)
Lean Body Mass 84.45% (120.59lbs) Vs 84.75% (121.96lbs)
Water 63.8% (91.11lbs) Vs 64.35%(92.60lbs)


I mentioned last week that I had been utilising a low carb (c10%) diet for the previous couple of weeks and it had resulted in my running feeling a lot harder than it should. The plan was therefore to switch to a higher proportion of calories from carbs (c50%) this week. The difference was almost instantenous not just in how much easier the running felt but it was also clear that my body was much happier utilising glycogen as part of the energy supply rather than just relying on fat, which is much harder for the body to convert into energy. I was lucky that Christof Schwiening (Physiologist, Neuroscientist and Marathoner) commented on facebook after I posted last week's blog. He said the following.


'You know when the carbs are really low because the heart beats per mile go through the roof. Also, the loss of muscle glycogen and water causes a weight drop of about 1.5kg. I tried about 8 weeks of ~30km per day fuelled off just one meal a day - I was definitely in a calorific deficit. The last run of the day, before I ate, was always a struggle - usually with a heart rate about 10 beats per minute higher for the identical pace (if I could even get to it). I think this is a fairly traditional approach for some runners, and my 'gut' feeling is that it does adapt something. Although, it could just be weight loss and psychology. I am not sure that the 'speed one can maintain' is necessarily a good indication of the value of a session. Carb-depleted training does limit speed (which might inhibit some leg muscle hypertrophy), but, it also pushes adaptations elsewhere. From an evolutionary perspective I suspect that the critical selection points that good endurance running could counter were probably at times of food shortage. One might therefore expect that optimal endurance training might also require recapitulations of such stresses. I am not suggesting we should all be running for our lives, short on water and food across hot deserts whilst being chased or hunting down our food....but, that is probably the type of stress our physiology responds best to.'


From what I can gather Christof suggests that training low will produce some very positive adaptations over time in terms of weight loss and the fact that when you do finally get carbs in your system there will be a big boost to how quickly one can run at a given intensity. All that being said, I really don't know if it's for me! Running was starting to not be fun and as it's only a serious hobby (and I enjoy my carbs too much) I think a more sensible approach for me is to try and just balance my diet over the week. If I was an elite athlete looking for additional marginal gains then sure, the periodisation of carb restriction might be a good idea but without a full time nutritionist and chef that might be a little ambitious.


This week saw three main sessions, the first of which was a 30 minute tempo run. I chose to do this on the treadmill given it was so windy outside which would have made keeping a constant pace virtually impossible not to mention how much it would play with my mental fragility if the pace was no where near where I wanted! That said the treadmill has the opposite effect of being highly flattering, in that you don't have any wind resistance to combat.  I set the Treadmill to 18kph which is c5:20mm but I have a footpod which I understand is  more accurate at reading pace than the speed displayed on the Treadmill. The pace for the 30 minute effort came out at 5:09mm (strangely however the footpod data implied I increased pace throughout despite keeping the TM speed constant) which as I say is likely to be highly flattering, but it was a good hard effort that I could have sustained somewhat longer had I needed to. The heart rate was getting up to decent levels by the end of it all though.


The second session was Friday's Fartlek of 3, 6, 9, 9, 6, 3 mins off 2:00 jog recovery. Having woken up to a very thin layer of snow/slush and temperatures very close to zero I again chose to do this session on the Treadmill. For the 3 minute efforts I averaged 4:42 pace allegedly, the 6 minute efforts, 4:48 pace and the 9 minute efforts 5:00 pace. This really did get me wondering how accurate my footpod is so decided to use the next run of the day to calibrate it on a known route's distance. It turns out that the footpod is remarkably accurate so I only had to adjust the calibration factor on the Garmin itself a tiny amount. We shall see what happens next time I run a session on the 'mill. I also decided to do a little bit of reading regarding the impact of wind resistance when running on the TM and it turns out that if running on a 0% incline, which I was then you can pretty much add 15 seconds per mile (at a fast pace) to the pace you recorded for the splits which would make the efforts for this session 4:57, 5:03 and 5:15 for the 3, 6, 9 minute efforts respectively. This is much more in line with what I would expect had I run this session outdoors in good conditions and fit and is pretty much exactly what Mike had wanted me to get close to for the session, so I suspect it was just about a perfect workout! The link above also has some very pretty looking HR graphs for those so inclined! I found a handy chart online which converts paces on the TM to equivalent paces outside based on speed and incline you have the machine set at. Whilst for sessions of this nature it probably makes sense to keep it at 0% incline as getting the legs turning over faster than they otherwise would is probably a good thing for me I do think there's an argument for me to start running my moderate and easy TM runs on a slight incline (perhaps 0.8-1%) to ensure that my aerobic efficiency number is not too positively influenced.


The next session was Sunday's long run which again had  a marathon slant to it. It was to be 18 miles at just under sub 6mm which I achieved quite nicely averaging 5:50s for the run. It did feel hard but then I suppose it would at this stage of the game in the context of quite a big week and only just getting back to proper training.


It was nice to see aerobic efficiency took a big leap forward, more than likely due to an uptick in fitness but also the return of more carbohydrate into my diet!