Part 4: Food for Thought.

In 1687 Sir Issac Newton published his book Philosophiæ Naturalis Principia Mathematica and in it were his three laws of motion. The second law as he defined it stated: that the net force acting on an object is equal to the product of its mass and acceleration, or F = ma. This law can be used to explain how an object's motion changes when an unbalanced force acts on it. When it comes to cycling these days there is a great deal of focus on that force, or as many of us have come to know it “power”. The formula for power is Force x Angular Velocity = Power and in actual fact our power meter doesn’t “measure” power, rather it measures Force and Angular Velocity and then multiplies one by the other. In cycling however power, or the force we act out against an object, is not the entire story when it comes to the control we have over this particular law or equation. We also have control over the Mass upon which the force is going to be applied, and in many cases in today’s endurance environment it is manipulation of the amount of this mass that offers the greatest radical improvement in performance for the majority of participants in a mass start race like the Marji Gesick.

Right here is where we have to insert the caveat: If you are any of the following: a young up and coming athlete, barely any body fat, already wafer thin, or extremely under-muscled then you need to largely ignore this post, or read and digest but then be extremely honest with yourself. Losing weight when we are already bang-on a performance race weight, or have gone beyond that point and are now playing dumb games with our future health is NOT what I’m advocating for you. In your case you need to get smart, eat more, and at the very least get back into some sort of energy balance for at least 6 months but preferably for the rest of your life. For the other 95% of us this post is good to go.

^^^that was my duty of care as a coach, and it should be enough. Sadly the coaching and endurance industry has reached a point where we’ve gone too far the other way. I’ve heard coaches and people in places of influence say things like “weight doesn’t matter” or “a little extra body fat will do you good” and whilst I get that it’s meant with the best intentions for the health of athletes who might go too far and strip out their health whilst trying to lose weight, the reality is that the more excess body fat, and even to some extent muscle, we carry the slower we are going to be on a bike, on foot, or a combo of both. Weight has an influence, and people that need to consider this the most often have plenty to lose and stand near zero chance of damaging their health any time soon. 

Now I know that some people take great offence when the subject of bodyweight or bodyweight comes up, and I’m a sensitive guy, so I’ll pick on myself and try to leave everyone else out of it. Let’s start by clearing my conscience: This time last year I was about 12 months, or one cycle of fat loss, away from getting back to my pro-elite bodyweight for the first time since 2010. Then I bust my knee, couldn’t ride, couldn’t really lift as much and so used those small setbacks as a good excuse to overindulge in all my favourite foods and quite a lot of alcohol. 2024 was supposed to be legendary year for me, but it wasn’t, because I sent myself back to my 2022 bodyweight, which to be honest isn’t so pretty. 26lb heavier to be exact. Before I left for the Marji my wife brought me this T-Shirt:

Ouch! Some might say this was a bit harsh but Jen knows me really well, she knows I’m already disappointed with myself, and she also knows that I find at least as much motivation from the mistakes and lessons in life as I do the success and wins. As it happens the T-shirt was too big so maybe I’m not as fat as she thought ;-) But when the replacement arrives I will wear it to remind me to move forwards and not back, because I could indeed try harder when it comes to getting lean and mean.

So how much difference does bodyweight make? A tricky question and one that is debated time and time again, with some claiming huge numbers and others poo-pooing the claims because, after all “a little extra body fat will do you good”. It’s always difficult in fairness to put exactly numbers on such things, because there are good and bad ways to lose weight. However I’m usually not so good at losing weight safe and sensibly and so I think I have a fair idea of how much performance I can gain even if I do it too fast, potential cause some performance decline but still end up lighter.

There are a few events or races that I enter most years, and my fitness tends to be relatively stable in comparison to my weight. So here’s a good example of what might be possible if one were to lose a substantial - say 26lb - from one year to the next. In 2022 and 2023 I entered the same local event we have here called the Dartmoor Legend. It’s a road event, mass start (4am just before sunrise) it’s 201 miles long and has over 20,000ft of climbing. I am blessed to live somewhere that has some of the best climbs in Britain and one of the highest ratios of 1:4 climbs to miles ridden. The Legend uses pretty much all of them! The weather was relatively similar both years although the roads were wet when we started, and it rained on the first of the main climbs in 2023, and so my descending speed was down a bit until the roads started to dry out in the afternoon. Both years it finished incredibly hot. My stats for both:

2022 

Time: 16:57:04

Average Power: 192w / 2.19wpk

Max Power: 423w / 4.82wpk

Average Heart Rate: 139bpm

Max Heart Rate: 174bpm

FTP: 257w

TTE: 0:40:28

Body Weight: 193lb

 

2023    

Time: 13:51:10

Average Power: 181w / 2.38wpk

Max Power: 399w / 5.25wpk

Average Heart Rate: 125bpm

Max Heart Rate: 169bpm

FTP: 248w

TTE: 1:11:07

Body Weight: 167lb (see image below)

There are a lot of other stats we could add to this mix, but these are the basic ones that people might recognise and they contain the major contributing factor that makes me so much faster in 2023. The biggest changes in the data from year to year are bodyweight (reduced by 26lb) and the time it took to complete the course (reduced by 3 hours!)

When we ride off-road any extra weight we are carrying tends to present a bigger penalty than on the road. Especially on anything that presents rolling resistance to the tyres, like sandtraps, roots and rocks for instance. So it’s not unrealistic to suggest that I might find a similar saving in time, or better, per mile travelled should I return to the Marji Gesick and have dealt with at least some of my excess fat and gotten myself back down to my 2023 bodyweight. It might be realistic to make the following suggestion:

If climbing was equal, the terrain equal, and they were both either road or mountain bike then we could expect to see a pro-rata saving in the time.

The Margi Gesick is 30.34% the distance of the Dartmoor Legend so the potential saving in such instance would be: 56 minutes. However we know that the Marji is off-road, technical and has more climbing per mile, so arguably we stand to save even more time than this if we were to lose 26lb over the course of the next year. BUT for arguments sake let’s just settle at 56 minutes because it is totally realistic in my experience working with athletes in mountain biking for the past 30 years. 

A theoretical 56 minutes reduces my time from 8:33:51 to a potential 7:37:51 which in this year’s race is 10th position overall.

So 10th position overall, at age 51, and riding a single speed. Very nice indeed, where do I sign up?

Right now someone with a physics degree is working out why I am wrong ;-) What they need to understand is that mountain biking is not just about physics. It involves a human, it involves physiology, and it involves hormones, and stress, and ATP, and economy of movement, and a lot of other things that all improve the less body fat I have on my body. It involves confidence and psychology and both improve when I don’t overheat as much, don’t need to eat as much so don't need to carry as much, when I accelerate without as much effort, and the bike slows down quicker when I brake and doesn’t try to stand up so sharply in the corners. In my experience the time saved off-road in technical terrain after losing weight is usually quite a bit more than the basic kids maths I just presented.

Weight matters, it matters a lot, and losing some makes at least 99% of humans faster on a mountain bike and at least 95% of riders do have some fat they can lose without damaging their health. The bigger I am the more I can improve speed through weight loss more rapidly and radically than through any other means.  

Action:

By this time next year I will weigh in at least 26lb lighter than I do today. What anybody else decides to do is completely in their court. My recommendation is that they at least think about their weight, work out if they are carrying any major excess of body fat, and then if they really, really want to go faster ask themselves the question: Could I try harder?