Interesting one, and certainly contentious at the minute. Does weight loss affect running performance?Massive problem in the athletics world (mainly for female athletes) who feel they've been bullied into feeling self conscious about their appearance and feeling pressure to take drastic measures to loose weight. Mainly from old school male coaches who have limited skills on dealing with the modern athletes feelings!
Most obviously less excess weight means less to carry around so for the same effort you will run quicker. I use the rough formula of 3 secs per mile per lb of weight you loose.
Disclaimer time - again a fairly obvious one - you have to get enough nutrition in ! Loosing weight needs to be done in a healthy way without compromising your training and / or health. Starving yourself and not getting enough nutrition will 100% NOT make you faster in the long term. Also, there will be a minimum limit you can achieve where you simply are not going to loose weight.
I am a 47 year old man weighing (as of this morning) 10 st 5 lbs. I have a BMI of 22.9. I can afford to loose weight to make myself faster. If I was 9 st 5 lbs then I doubt weight loss would have much affect at all. The important word here is excess.
I am currently a very healthy weight. I could put on half a stone tomorrow and I'm still not going to get called fat. In fact when I was cycling I was a stone heavier (mainly all the coffee and cake stops).
So anyways, loosing weight and performance improvements. I use a Stryd power meter for almost all my runs. Power is my main metric for pacing a race and training longer intervals and tempos. When I race I have only power showing (it beeps each mile) that way I don't get distracted from GPS errors. I can use the mile splits from Garmin, known mile points or course markers for distance BUT power guides me as I know how I am going to finish up based on percieved effort and current power.
Looking at Storys Field Parkrun I have lots of data but 2 good days stand out -
|
August 14th |
October 23rd |
| Time |
17:14 |
16:42 |
| Power |
338w |
335w |
| Heart Rate |
167 bpm |
168 bpm |
| Shoes |
Alphafly |
Metaspeed Sky |
| - Lap 1 |
5.31, 340w, 159 bpm |
5.17, 336w, 159 bpm |
| - Lap 2 |
5.32, 339w, 171 bpm |
5.18, 338w, 171 bpm |
| - Lap 3 |
5.37, 335w, 172 bpm |
5.26, 330w, 173 bpm |
For less power and almost exact same heart rate I was 32 secs faster. Interestingly the pattern was similar of holding on for the second mile and slowing slightly on the last mile and that is the difference between an A race and a Parkrun where I want to still feel I have some in the tank!
Shoe difference explained below by reviewing whats happening -
Air power 0%
VO 8.22 cm
GCT 179 ms
Cadence 180
Air power 1%
VO 7.93 cm
GCT 180 ms
Cadence 183
First set of results was the Alphafly and second the Metaspeed Sky. Basically the Alphafly are bouncier so I travel further for less cadence. This effectively cancels each other out - to say that basically they give very similar net results. I'm taking more foot strikes with the Metaspeed BUT only 50 over the course of the race and if you factor in the slightly less weight of the Asics that again just nets back to roughly zero. Long story short they are as good as each other. I race in the Asics from personal preference but I am not going to get a noticable difference in either shoe!
Conditions were worse on the faster run (colder and slight wind) BUT not what I would call noticeably. Again I'll split the difference and call them even.
Finally I will note that at less weight, similar power is more effort but at these numbers, weights and heart rate we can agree that these numbers are almost identical efforts.
So the real difference - body weight around both races. This is difficult as I weight in at different times and weight naturally fluctuates BUT
August 13th (154 lbs) August 14th 150 lbs - post race)
October 22nd (146 lbs) October 23rd (147 lbs - post race)
Average out 2 days 152 lbs v 146.5 lbs that's 69 kg v 66.5 kg
So 2.5 kg = 32 secs over 5k. Lets call it 16.40 and 30 secs for ease of math ;)
2.5 kg extra weight loss would mean 16.10 for exact same conditions and race shape. 10+ extra secs would be an extra 850g (ish) which gives me a weight loss target of 3.35kg.
Convert this all back to real money and we have a target weight of 63.15 kg (139 lbs OR almost exactly 10 stone)
Today I was 145.9 lbs (66.1 kg OR 10 st 5 lbs) - so weight is in the correct direction. Can I get there, who knows. If I am honest I am serious about hitting targets BUT I'm not that dedicated to weight loss to really give that much of a toss !!
If anyone is seriously interested in loosing weight it's 100% better to track using something like My Fitness Pal. Being coeliac I do find it easier to avoid junk.
The best tips I find in monitoring weight are -
* Focus on protein
Especially after training. 2g of protein for every kg of body weight per day. Try and get 40g per meal and I take a protein shake immediately after exercise. I never used to do this but it's an easy win (25g of protein)
* Lay off takeaways & snacks
Obvious one but it's surprisingly hard to get your calories from home cooked nutritious food BUT it's surprisingly easy to fly over your target eating non nutritious snacks and takeaways
* Lay off the booze
Basically not much fun here but not only is boozing going to take up loads of calories but it'll also make you choose junk food snacks. I drink skinny beer as it's gluten free but it's also only 85 calories so not a bad option if you are going to (plus it tastes decent).
* Get carbs in before exercise
Trust me, you feel shit if you train carb free.
* Be a slave to routine
I have pre-session breakfast of GF pancakes, jam and banana EVERY SESSION. It's 350 calories but gives me more than enough energy. That and coffee ;)
If I'm not doing a session I have GF pancakes, poached egg and ham. And lots of coffee !!
Lunch I usually have a tin of Heinz sausage and beans. Good protein and fills me up.
Be happy to eat same foods daily, make the most of days off when you can eat out but get a nice routine and remember food is fuel.
* Get in fibre
Another good source to target. I struggle here, need to focus on this going forward
And that's about it. I am lucky Ange makes healthy nutritious dinners. Most nights I end up having 1 - 2 bags of crisps as I have carbs and calories left. I don't track religiously but try to maintain some discipline.
Yes, I also have the option to just train extra hard and create more power (I think roughly 355w would equate to 15.5x for 5k) but where is the fun in that - plus imagine I do both !!
At the minute this is all moot as I am carrying a niggle wrapped in an injury BUT I am hoping the fizz gets to the bottom of that this week and we can move onwards.
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