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Sports physiology deals with the chemical mechanism by which things happen in the body. It's one of the three key sports sciences along with psychology and biomechanics.

Cycling vs. Running ‘which burns more fat?’ and ‘which is harder?’

I’ve followed a thread on the Facebook and there some views aired on ‘which burns more fat’ and ‘which is harder’.

So which is it? Lets find out:

Muscular stress

Running is a high impact active, it involves repeatedly striking the ground with impact force of roughly 2 -3 times body weight. That means that as a 70 kg human being, your leg muscles, bones and ligaments are subject ~210 N of force every single step of the way. Now cycling, on the other hand has negligible impact. The bike is supporting your body weight and eccentric forces acting on the musculature and bones are negligible. It’s worth noting this is true of road cycling, but not mountain biking.

Muscle contraction type also differs. In cycling muscle contractions are concentric, that is the muscle is lengthening. This is also the type of contraction that produces the least force. In running there’s the whole array of muscle contraction type: concentric (in propulsive phases) and eccentric on the breaking phases. The degree of muscle activation in the running movement actually occurs just before ground contact in running as the body ‘pre-empts’ the impact.

So which is harder on the muscles? Running by far. This is the reason we see bike races lasting weeks, while just one marathon takes weeks to recover from. You can do a massive amount of cycling before needing to stop.

Why is it ‘easier’ to run hard than cycle hard? In cycling the volume of muscle used by the activity and requesting oxygen from the respiratory system is less (60% versus 80% in running).

Ventilatory and cardiovascular stress (heart + lungs)

In both sports, trained athletes are able to attain ‘VO2max’ -that is maximal aerobic capacity, or the maximum amount of oxygen that your body can absorb. The body, like a combustion engine needs oxygen to produce energy: fuel + oxygen ≅ energy; heat + work. VO2max represents a ceiling of how much energy can be ‘burned’ aerobically. Where VO2max can’t be attained it’s unlikely that that exercise will be as effective at burning fat as these ‘big muscle group’ exercises. Other factors leading to performance in sport are efficiency and energy derived through other (anaerobic) mechanisms, also at which point one reaches Lactate threshold (LT), which varies from sport to sport and basically defines rates of sustainable exercise.

For sub-maximal exercise, a roughly linear relationship  exists between heart rate and energy expenditure -regardless of exercise modality; the unit cost of oxygen per amount of energy remains very similar regardless of ‘metabolic substrate’ (that’s fuel; Carbs, Fat, Protein). So what we’re seeing is if you cycle at the same intensity you run, you’ll burn round about the same amount of energy!

Excess post-exercise oxygen consumption (EPOC) is also about the same when comparing cycling and running, so post exercise fat burning remains about the same for both.

So which is harder on ventilatory/cardiovascular system? They’re the same more or less, it depends how hard you exercise and not how you exercise.

So which burns more fat? We’re back to the question of exercise intensity, rather than modality…

N.b. one important aside: LT will likely come a different stages in the same person doing the two sports. Generally LT is higher while running than cycling, except trained cyclists: If you’re a runner, runner is ‘easier’. If you’re a cyclist, cycling is easier. If your neither, then running is easer. Non-cyclists find it hard to reach VO2max on a bicycle.

Mental stress

The much ignored nervous system: the one that actually gets you up, out and exercising is obviously also an important factor.

Both sports provoke a large amount of cognitive load to people new to them: There are literally billions of ‘factors’, degrees of freedom open that the mind has to deal with. Think about what’s going on: posture, muscle activation, sensory feedback from the body, sensory feedback from the environment, cognitive interference, spatial processing and navigation, etcetera… An awful lot more is happening that just sitting on the couch! This can cause an overload of the neural structures that have to process the information. Hence it is interpreted as ‘unpleasant’ by those unaccustomed to momentum sports. People beginning sport often make subconscious efforts to reduce cognitive load by exercising indoor, listening to music, exercising at a reduced intensity, picking exercise modalities which minimize the amount of, or disassociating themselves from the activity at hand by using distraction techniques, such as counting strides, singing, thinking about something else.

With practice a person develops automatic ‘coping mechanisms’ (schema) where things that would normally take up their attentional resources become automatic.

So which is ‘less stressful’ I am not aware of a comparison between exercise modality and rate of arousal (although it probably has been done), so have to go on common sense here. I would guess running causes a greater amount intrinsic stimuli while cycling causes a greater amount of stimuli from the environment. In colloquial: Running hurts more than biking, but the movement is slower, so you have less things like cars, obstacles, dogs and potholes to deal with, biking is more stressful due to environmental factors. Given rates of participation in sport I’d guess about the same as cycling and running have a very similar amount of participants.

Coming next we’ll get Ricardo to throw swimming into the equation.


Nilsson, J. and Thorstensson, A. (1989) ‘Ground reaction forces at different speeds of human walking and running.’ Scandinavian Physiological Society,  136(2) pp. 217-227.

Scott, C. B., Littlefield, N. D., Chason, J. D., Bunker, M. P., Asselin, E. M. (2006) ‘Differences in oxygen uptake but equivalent energy expenditure between a brief bout of cycling and running’ Nutrition and Metabolism, 3(1).

Keytel, L. R., Goedecke, J. H., Noakes, T. D., Hiiloskorpi. H., Laukkane, R., van der Merwe, L., Lambert, E. V. (2005) ‘Prediction of energy expenditure from heart rate monitoring during submaximal exercise.’ Sports Science, 23(3) pp. 289-97.

Ekkekakis, P. and Petruzello S. J. (1999) ‘Acute Aerobic Excercise and Affect.’ Sports Medicine, 28(5) pp. 337-347.

Wilson, M. (2008) ‘From processing efficiency to attentional control: a mechanistic account of the
anxiety performance relationship.’ International Review of Sport and Exercise Psychology, 1(2) pp. 184-201.

Derakshan, N. and Eysenck, M. W. (2009) ‘Anxiety, Processing Efficiency and Cognitive Performance. New Developments from Attentional Control Theory.’ European Psychologist, 14(2) pp. 168-176.

Sport England (2013) Active People Survey 7. [Online][Accessed on 14th November 2014]

Interval training for cycling

learn about interval training for cycling. And how to get it right.

Interval training first came to prominence in athletics in the late 1940’s and early 1950s. Roger Bannister the first man to run a mile in under 4′, was an early adopter. Road racing is a highly dynamic sport, utilizing all metabolic path ways, hence historically cyclist unwittingly did ‘interval training’ simply by racing their bikes. However I’m not going to talk about it’s history, I’m going to talk about it’s application in cycling and various types of interval and explain what exactly it is a training plan or a coach seeks to do with interval training.

it hurts, it’s difficult, I don’t notice much difference, why bother?

With interval training you’re training muscles to work at intensities they aren’t used to, for longer that they are used to. Then they adapt to this higher work load, something that wont happen from training steady state (a continuous, even rhythm). Hence you become faster. One big plus of of interval training is that it’s time economic: train less for the same effect.

… The total training time commitment was approximately 2.5 and 10 hours, for the sprint and endurance groups, respectively… …The two very diverse training protocols induced remarkably similar changes in muscle oxidative capacity and exercise capacity. M. J. Gibala (2006)

types of interval training

Interval intensity is usually maximal, that is you go as fast as you can for a given period of time: A better way of thinking about is you try and do a certain amount of work in a set period of time. This means that you don’t go too fast at the beginning that you can’t complete the effort or go so slow the effort is too easy.

The rest period in interval training is critical because it also defines the training effect through controlling the rate of accumulation of fatigue. Hence you need to pay attention to both and stick with it as the going gets tough.

common types examples

1 minute at maximum intensity, 1 minute recovery

This brutal session provokes an accumulation of lactic acid (1′ isn’t enough to completely recover from the previous interval). It trains the system that derives energy through anaerobic glycolysis, that is, sugar is burnt without oxygen.

A typical session is 6 * 1′ (as hard as you can) * 1′ recovery (either active or static)

1′ interval session: checkout the the decline in performance (speed) as lactic acid builds up

30 second sprint by 90 second recovery

Sprint power is provide through two metabolic pathways: ATP present in the muscle (ready energy) which gets depleted after a few seconds, followed by PCr (Phosphocreatine) system, which extend this ‘sprint power’ up to 30′-40′ seconds and is part of the reasoning behind creatine supplements (I personally don’t encourage indiscriminate supplement use of any type). 90″ is the bare minimum recovery period needed for these systems to ‘reset’ ready for action again.

Try introducing sprints to your warm up routine.

Sprints are an important part of a complete warm up.

tempo ridding

Tempo riding is riding an interval that extends for long periods of type: 40′ -2h. This is good for developing endurance and a lot of people like to train this zone preferentialy. Beware that while this improves endurance, it generally has an opposite effect on power. This trains the ‘aerobic system’ and energy is derived from sugar mostly, but also fat.

This is best done in a group, it’s tough alone!

12′-20’lactic tolerance with 15′-20′ recovery

These intervals are hard, usually when you see rider racing on the long mountains they are in this zone. It’s the zone that uses sugar nearly exclusively.

what interval is right for me?

It’s counter intuitive, but interval training is good for people who want better endurance, and speed. So it’s worth including in training for every type of cyclist.

Start by developing speed and power with short interval then develop endurance with tempo and lactic tolerance interval. That’s how I do it anyway.

how much should I do?

Not much. It’s hard going. 2.5- 3 h a week is sufficient, divided into at least 3 sessions (one every 2 days).


Before embarking on any training plan I suggest doing a sports medical, to make sure you’re apt for exercise.

the metabolic mix -the fuel for endurance sport

diet, training for endurance sport

This article targets sports enthusiasts with little knowledge of the mechanisms underpinning training.

The main myth I am going to debunk here is the idea that you burn more fat at relatively lower exercise intensities. This statement is an over simplification that I think doesn’t help anyone wanting to get started training, as it’s leading people to train softly when maybe bumping it up a notch is the better solution, especially for the time constrained.

What is the metabolic mix?

Your body is a remarkable machine capable of burning nearly every type of fat, protein and sugar for fuel.

The metabolic mix is the mixture of energy sources that’s used for a particular intensity of exercise. These substrates (or fuels) are most commonly sugar called ‘glycogen’ in physiology speak and fats. There are more types of ‘fuel’ and metabolic pathways. Metabolic pathways refers to the many ways your body can process and break down energy ‘substrates’.

It’s possible to deduce what mixture of fuels is being burnt in the body through the expiratory exchange ratio: That is the quantity of carbon dioxide and oxygen in the exhaled air. However, a guestimate is accurate enough for our purposes.

At sub-maximal exercise level (that’s sustainable, without burning in the muscles and controlled breathing) it is possible to use the respiratory exchange ratio to know more or less the ratio of carbohydrate to fat being burnt. It’s estimated on the ratio of oxygen consumed and carbon dioxide produced. When this ratio is 1 or higher carbohydrates are the predominant fuel source, as fat doesn’t burn in absence of oxygen only glycogen and very inefficiently.

Diagram of the metabolic mixDiagram showing the various fuel sources at differing exercise intensities.

Fuel sources for exercise

The harder you exercise, the more you burn -of everything- so training at threshold,since energy demands are much higher, the fact your burning proportionately less fat, doesn’t mean your burning less fat on the whole. Maximal rate of fat oxidisation 74% maximum heart rate or 64% VO2max. Above this level the rate of fat oxidisation drops of rapidly. Proportionally more CHO is burnt versus fat as exercise intensity increase. Also the longer exercise last, the more protein you burn, hence (rather ironically) endurance athletes have about twice the protein requirement of whey protein guzzling weight lifters at 1.5 g per kg in times of hard training. P.s. you need not guzzle litres of Whey protein but having a diet rich in beans, fish and milk products is enough!.

Lipid power

Lipid power is one very important factor in endurance sport performance, because although it wont win you races (well, not counting ultra-marathons and the like) it is the engine that does the bulk of the work in any long endurance race. By definition lipid power occurs somewhere around aerobic threshold, a fictitious threshold: A purely aerobic effort doesn’t exist, even when you sit down doing nothing your metabolism is predominantly anaerobic.

Lipid power is easily trainable and some (tough) changes to lifestyle and diet, like favouring proteins and fat over CHO (think in terms of a Mediterranean diet). These changes can bring around an even more succinct change than training alone. Generally, lipid power is trained through ‘long slow distance’, although there are smarter ways to train this. The aim is to teach your body to burn fat in place of CHO at intensities where normally CHO is favoured. The effect of just diet or exercise can be so succinct it even effect metabolic gene expression… It’s quite amazing what the human body can do.

Where it becomes difficult

Keeping with a healthy range for body fat isn’t difficult for normal individuals doing up to 10 h of exercise per week. With elite athlete weight regulation and controlling body fat is not easy, nor is it automatic. It takes a huge amount of control to have weight dip to 5% or bellow in a controlled and healthy manner. The problems arise from the fact the even the smallest slip in diet and regime have an impact. Most of the elite athletes I’ve trained are surprised by just how skinny they need to perform, especially in cycling where every change in gradient, every acceleration is affected by weight.

I’ve kind glossed over this subject here and the truth is it’s very interesting and deserves more attention. So I’ll redress it bit by bit in the future.

References available upon request

training specifically

Are you training specifically?

Training specifically, is training with a purpose. If you want to sprint faster, you need to train sprints and other ‘training stimuli’ like strength (weights in the gym for example) or power (plyometrics). Likewise, if endurance is your thing there are a number of training stimuli to improve your performance specific to that activity.

Choosing objectives:
When choosing your sporting objectives, people often just do something because they like it, or like the idea of doing it. However, they might become disillusioned when they find they’re not good at it (like me and football!).

Imagine a cyclist, you’re very light, have a high power to weight ratio, not good at sprinting, has a poor recovery. You tell me you want to win a certain stage race, say the ‘Tour of Normandy’ (the Tour of Normandy is usually very cold, no long climb, many short drags and suites for ‘baroudeurs’. ‘puncheurs’, or ‘rouleurs’ and sprinters, or cyclists that go well on the flat). What can I do as a coach?

Tour du Normadie

Firstly get some idea of ‘engine size’, i.e. the athlete’s capabilities across a range of training zones then choose which one to improve (I believe in training to our strengths personally, with the bare minimum training of out weaknesses to be viable in other race setting). Measure that capability and train it.

I’d tell the cyclist he’d have a better chance in some one day climbing race (not man of those!) like Vuelta a Rioja, Klassica Primavra, Subida ao Naranco. And hopefully he’d agree and I’d coach him according to his strengths.

video of Subida ao Naranco… a very different race.

How does it all come together?

Our athlete in the first paragraph will get a schedule with the precise values and sensations to train for in order to go well in those hilly one day races. In his case he he’ll be working most lactic tolerance, with some lactic power in the weeks coming up to the races, and with rest periods obviously. Time is important and the training will be developed in such a manner that he will only start fine tuning his capabilities on that terrain close to the time, so as to ensure he doesn’t over do it and arrive there stale.

Hopefully the cyclist will be right up there in those hilly races doing his best and with a chance to win!

Train healthily

Some tips on how to train healthily.

Sport is generally seen as something healthy. This isn’t quite true. Sport done with any seriousness can have a negative effect on your health and it’s important to watch out and learn how to train healthily. Here are some tips:

sports doctor

Find a doctor that understands sport. There are many peculiarities to athletes that mean that a normal doctor might fail to understand certain problems. A sports doctor is also best placed to advice you on how to train healthily for your specific case (e.g. if you have any particular condition).

sports medical

Have your sports doctor conduct regular test that include ECG and blood test, a ramp test and whatever else deemed necessary. These must be done at least once a year.

VO2max (ramp test)
VO2max test -ramp test


Sport is just as much about rest as it is about training. While training is good fun and practically and addiction for many athletes it’s important to train in a sustainable manner.


Over use problems wont occur with correct technique and equipment set up. In this situation you need a mixture of science and common sense.

For example: with bare foot running: if you’re using minimal footwear or are bare foot you should not slam your heel into the ground as you would in a pair of running shoes.

I would suggest seeking a professional bike or shoe fit if possible.

pre-conditioning (pre-season)

Pre-conditioning is tricky, it’s a tough one to explain as a coach. Pre-conditioning is the process of preparing your body for exercise. Ambulatory sports (walking, running), gym and even some contact sports (with due care) are all great ways to prepare for proper training. As with everything: Start easy and build up.

fads and quackery

There is a lot of quackery about training and sport, like ‘balance bracelets’, training with loads of clothing in hot weather, extreme diets, overloading on supplements. If you’re in doubt about something just don’t do it. Beyond genetics, training, lifestyle and diet there’s not much to be improved.

listing to your body.

One very important point: You do the training, you know what’s best. What a coach is doing is advising. Even a full training program might have some error in it (e.g. training zones that don’t add up perfectly) and it’s important for you to recognise when you are over doing it or training incorrectly.

adequate nutrition

Food is the first thing people get peculiar about when they start a fitness routine… Don’t cut food down, don’t go hungry, you’ll be depriving your body of important nutrients for recovery and fuel for training.

if in doubt…

Find someone that has a better idea of your situation and can advice you or tell you who can advice you.