Snow drops and improved aerobic fitness

I am just back from an easy 10K run in the woods and along the river bank. We are now at the mushy end of a thaw that set in two days ago. At the edge of the village, two slumping lumps of snow are all that remain of a snowman and his partner; a sad demise on St Valentine’s day.  In the woods a few drifts of mushy snow remain and some mini ice floes float in scattered puddles, but the paths are mainly mud. 

 

Staying upright is almost as difficult as it was on the sheets of icy snow last week.  Mud does not raise the spirits in the way that snow does.  However, the clumps of snow drops in full bloom provide some compensation and the thick green carpet of bluebell shoots indicate that spring is not too far away.

 

The River Trent is in spate, swollen with melt-water but still far from bursting its banks.  Nonetheless, the ancient mill race on the escarpment side of the riverside path, but connected to the river by a tunnel, is full of water.  On account of the mud it took some time before I developed a good rhythm, but in the final few Km I was running fluently and comfortably at about 5:30 min per Km.

 

In November, at the time when I decided to re-introduce several elliptical cross-training sessions into my weekly schedule, I had developed a simple test of aerobic fitness.  I record heart rate in the final 15 sec of a series of consecutive 2 minute intervals.  At the beginning of each interval I increase the resistance but maintain a constant cadence so that power output increases in a series of 7 steps spanning the aerobic zone.  Before my run today I did this aerobic test as a warm up, and was pleased to find that my heart rate at each level of the test is about 12 BPM lower than it was on November. 

 

In part this improvement is due to the fact that my asthma is much better today.  There was scarcely a trace of a wheeze. My performance on this test fluctuates day by day depending on how wheezy I am.  It is probable that I will not do as well in future on days when the wheezing is worse.  However even if I were to take the average the most recent three tests and compare with the average of three tests done in November to smooth out the daily fluctuations, there would still be a definite improvement, perhaps by around 5 BPM at each level. 

 

 

Heart rate v power on the elliptical cross trainer

 

 

 

 

This improvement has occurred over a period of three months during which I have done 2 or 3 easy (or moderate intensity) running  sessions and 3 to 5 elliptical sessions per week, apart for a few weeks in which training was curtailed by injury.  The majority of the elliptical sessions have been in the upper part of the aerobic zone (30 – 35 sessions over the three months). I have done a total of 5 sessions in which I exceeded lactate threshold, and 4 sessions in the lower or mid aerobic zone. 

 

One good thing about elliptical training is that it does not produce any appreciable leg muscle soreness on subsequent days.  This is almost certainly because of minimal eccentric contraction.  The lack of eccentric contraction during the elliptical sessions will probably have resulted in some de-conditioning of my legs, and it is unlikely that I could run anywhere near my potential best over 10K or a half marathon at present.  The interesting question is how much running will be required to re-condition my leg muscles for running.  Whatever the answer to that question, it is pleasing to know that I have been able to improve aerobic fitness substantially without stressing my legs.  

Snakes and ladders

I recently devised a test of cardiac fitness based on the relationship between heart rate and power output on the elliptical cross trainer. At home we have a Tunturi C6 elliptical, which I had bought as a present for my wife almost 4 years ago, at a time when she had expressed an interest in getting fit. After about three sessions on the Tunturi, she took up cycling to work and has continued to do so ever since. So the Tunturi achieved its purpose, but not quite not in the way intended. For the past four years it has mainly stood un-used in the guest bedroom. From time to time I use it myself, though I find it far less interesting than running in the country-side.

However, it does come fitted with a power meter and heart monitor so it offers the possibility of a test of fitness that is independent of the weather and the bogginess of the woodland or riverside paths.

My recently devised test consists of consecutive 2-minute epochs at 160 steps minute with six step-wise increases in resistance such that power output increases in steps spanning the range 30 watts to 230 watts. I record average heart rate in the final 15 seconds of each 2 minute epoch At my present level of fitness, my heart rate when generating an output of 30 watts is around 90 and rises in a straight line to around 145 at 230 watts. It should be noted that my actual rate of energy consumption is much greater than indicated by the power meter. Comparing the power meter reading with the estimated energy consumption (in Kcals/min) demonstrates that for a 63 Kg person, about 83% of the energy consumed is spent overcoming internal friction in muscles, ligaments and joints, and ends up generating body heat. The rate at which the sweat pours off me confirms that a large proportion of the energy is spent heating the body.

The attached chart shows the graph of heart rate v. power output on 17^th November (filled diamonds), before I commenced my recent back-to-back moderate intensity training sessions; and two weeks later on 30^th November (open diamonds) when my fitness had improved quite noticeably. HR was about 10 bpm lower than on 17^th November across the entire aerobic range. I tested myself again today before my run. The open triangles indicate today’s HR readings and demonstrate that my recent bout of flu has taken me back to a level of fitness only marginally better than on 15 November. In this game of snakes and ladders, fitness is gained with great effort and lost very easily.

After the fitness test on the elliptical I went for easy 10K run in the woods. The woodland floor is still thickly carpeted in leaves, mainly the rich brown of beech and somewhat more sombre brown of oak, but to my surprise, green shoots that look like sprouting bluebells were pushing their way through the leaf cover. Maybe they were snowdrops, which are more likely in December, but they looked like bluebells – so even though this winter has so far been chillier than recent winters, it appears that global warming is causing confusion among the woodland flowers. I did not have my camera with me, but I have pasted a photo which I took at the beginning of May 2008, in the header of my blog. Maybe in 2009 we will have scenes like this before mid-April.

Is my efficiency improving?

I have now done three runs since settling on the style described in my blog on Mechanics of Efficient Running posted yesterday, and I have been practising the swing drill daily since I developed it 4 days ago (amidst the ennui of Boxing Day). For each of the three runs since Christmas, I have had a very strong subjective feeling that I am running in a more relaxed manner than previously. Furthermore, I have been free of significant musculoskeletal aches and pains.

Today’s run was a 15 Km run at 4/10 effort over a path that is fairly flat apart from 5 short, sharp hills. For many months I have been using this run to gauge my fitness. So, although it is far too early to draw any firm conclusions about improvement in efficiency, I thought it would be interesting to compare today’s run with my two most recent runs over the same course under comparable conditions. Those two were on 25^th November and 2^nd December.

After a relatively substantial amount of training in the summer, when I ran an average of 50Km per week over a period of three months, I have decreased my running since mid-September to around 25Km per week. Therefore, I suspect that I have not increased my cardio-respiratory fitness since September. This is confirmed by my resting heart rate with reached an ‘all-time’ low of 44 beats/min in the summer, rose to 48 by the end of November and is now 51. Therefore, my subjective experience that I am running faster for a given degree of effort since adopting my new style is unlikely to be due to increased cardio-respiratory fitness.

With this in mind, I was interested to look at the performance data for today’s run compared with the comparable runs at end of November and early December. On 25^th November my time for 15Km was 82 minutes and mean heart rate was 131. On 2^nd December, the time was again 82 minutes and mean heart rate was 129. Today, my time was 79 minutes and mean heart rate was 130. The very similar mean heart rate recordings confirm that I had adjusted the effort to approximately the same level on all three occasions. However my time today was almost 4% faster than on the other two occasions, and was in fact the fastest I have ever recorded over this course. So my subjective experience that I am running faster at the same effort was confirmed by the data from heart rate monitor and stop watch, though a 4% improvement on a single run is unlikely to be statistically significant. This evidence is at best anecdotal.

The other important issue is musculo-skeletal stress. For the past year I have recorded musculo-skeletal aches and pains in the morning and evening every day. I rate the aches and pains on a numerical scale which I devised myself. This scale places emphasis on pre-existing problems with my right knee and also with metatarsalgia (pain in the right forefoot). My average evening score throughout the year on this numerical scale is 2.5. The score is usually a little higher after a long training run. My peak evening score so far, recorded on three separate occasions during the summer, is 6. On both 25^th November and 2^nd December, after the 15 Km run, the evening score was 4. Today it is 2, with contributions from very mild metatarsalgia and mild generalised muscular ache. My knee is fine, and I have no focal muscular pain. So the evidence suggests that my new running style does not exacerbate my musculoskeletal problems. So far, so good!

It would be foolish to draw too many conclusions from a single training run, but these observations do at least suggest that my new style has not caused any deterioration in my running efficiency. The important question is what will I be able to report after several months.