The story of "-2s/lb/mile", Project 5k takes off!

Doris' story
I have been following Doris' blog at http://doriscbwong.blogspot.com/ especially on her fight against obesity.  Am impressed with her continuous mental and physical attempts to keep her weight under control.

(picture from doriscbwong.blogspot.com)

At the beginning of this year, Doris posted a blog entry http://doriscbwong.blogspot.com/2010/01/2010-resolutions.html sharing her 2010 resolution.  One of her resolutions is to be able to run a Full Marathon (in either Venice or Frankfurt Marathon) in 4hr 40minutes by losing some weight and putting in some tempo runs in her training.  At that time, her personal best was 5hr 12minutes.

Interestingly, in her research into some sources, she mentioned that every 1lb of weight-loss can be translated into 2s faster per mile of running.

I believe that the formula only works for runner who are over-weight and who trains running regularly.  It would be illogical to assume that one could gain speed by merely losing weight without training.

Doris' 4:40 target finishing time was calculated based on her current personal best (as of Jan,2010), her weight (on Jan,2010), and her target weight when running Venice/Frankfurt Marathon (Oct,2010).

10 months passed, has Doris achieved her resolution by running 4:40 in either Venice Marathon or Frankfurt Marathon?  Yes... I was delighted to find out from her blog that she successfully did a new personal best at Venice Marathon by slicing more than 1/2 hour from her previous record!!!  Congratulation to Doris... and hat off!

I did a little surfing through her training record to see how she trained and how her weight changed.  I believe she did not run Venice Marathon with her target weight of 70kg, but I think she did run the race with much less excess fatty baggage with much more muscle mass and stronger cardio.

So, regardless of the accuracy of the formula "-2s/lb/mile", I think in the effort to keep the weight low by doing the RIGHT things, Doris is directly or indirectly benefitted.

Lesson learnt
Looking back at myself, since I took up running as sport in 2009, my weight has been maintained at 70kg with BMI of 25.7, which is in the overweight category by BMI.  Yes, many sources also say that BMI is not an accurate measurement.  Anyway, for its simplicity, it did give me a quick insight into my current state of weight considering I am not overly muscular.

According to BMI, my ideal weight should be between 51kg to 67kg.  Taking the halfway point between 51kg and 67kg (i.e. 59kg), if -2s/lb/mile is accurate, with my current state of fitness (or un-fitness), I shall be able to achieve

(70kg - 59kg) X (2.2lb/kg) X (26.2miles) X (-2s/lb/mile) = -1268s or 21minutes reduction in Marathon finishing time!

Putting physic and truth aside, isn't that beautiful psychologically?  I just have to do what I have been doing and by eating less, I can gain 21minutes reduction in Marathon finishing time!

Now, I am determined to lose at least 5kg, and that mark the begining of my project 5k.  The motivation...

"Reduction in Marathon finishing time without doing extra!"

Beautiful!  The story continues...