Bike STRENGTH, not power

December 27th 2018

By Linda Hill
Categories: Cycling

Bike STRENGTH, not power

Does a triathlete really need a power meter?

When it comes to training, and racing, we are universally persuaded that a power meter for your bike is essential and tends to be everyone’s primary assessment of development.

If powers up, good. If it’s down, bad!

But… is, and should, “power” be the unit of data we are really interested in? From a coaching point of view, we don´t use power as a measure, we simply get our athletes to develop bike strength. Whilst this results in increased power, power is not the primary objective!

What is power?

To help describe our point, we must look at what power is.

Power

Verb – move with (great) speed or force

Cycling power is the measurement of how much energy (force) is being applied to the bottom bracket, and so transferred to the bike for motion.

The mathematical formula for calculating pedal power is:

Force on Pedals x Speed of Pedals = Pedal Power

Or

The power is the force applied to the pedal (through a circular motion) multiplied by the speed in which the pedal revolves around the bottom bracket.

As described by Science Learning Hub, NZ:

if the cyclist applies a force of 150 Newtons to the pedals (150N is the force needed to lift a 15kg mass) and the speed of the pedals in a circle is 2 metres per second (2m/s), the pedalling power output of the cyclist is:

 Pedalling power   =    force on pedals   x   speed of pedals

     =         150N                   x          2m/s

     =        300W

Therefore, to increase power, one must apply force constantly throughout the 360° range of movement – and do it quickly to generate more power. There are a couple of important points here for the triathlete to consider:

  1. Applying force on the downward portion of the pedal stroke is “easy” as we are biomechanically suited to this action. However, we are no-where near as strong or biomechanically suited to do the “scrape-back” and “pull up” action;
  2. However, for a cyclist who may “feel” the pedals (and not all cyclists, even at elite level have this feel), this is a technique worth pursuing; but don’t forget they only have to cycle!
  3. Developing the “feel”, like any skill, takes years (of work through puberty) and if you don’t have it, you won´t be able to do it! BUT what you will do is to use the hamstrings, hip flexors and calf muscles a lot.
  4. Finally, guess what – as a triathlete you need these muscles (hamstrings, hip flexors and calves) to run after the bike!

Do power meters make the rider?

We know that good cyclists do generate a lot of power, but is it because they use a power meter?

Prior to the days of power meters, cyclist knew that they could generate power, it just wasn’t easily measurable. However, they, and their coach, knew that they had to get stronger if they wanted more power. Training consisted of a lot of strength training built on top of A LOT of aerobic training – riding hills, into strong winds, etc.

Now we know that power is a measure of 360-degree force and speed, and that strength is a simple basic attribute that can be developed, we can discuss why strength is more suited to triathlon / triathletes.

Why we don’t use power as a primary focus for triathletes

Considering the different demands of the sports (cycling compared to triathlon), the ability of the individual (usually starting at a late age) and the time restraints for training, we take a different (unorthodox) approach to bike training for our athletes.

The traditional cycling technique is to use all 360°  of the pedal revolution – push down, scuff back and then pull up. When you apply this to a triathlete training and competing in an Ironman event, think how many pedal revolutions there are:

Assuming a cadence of 75rpm and riding for 6hrs, there are 54,000. Compared to the traditional approach at 90rpm = 64,800 revolutions! This gives you an idea of how much energy and muscle recruitment is needed.

Rather than a 360° power application, we coach to our athletes to get “super” strong and push down ONLY – to “STOMP”. The STOMP happens from the 1-5 o’clock position and then the leg relaxes for the rest of the revolution. This drastically cuts down on:

  • muscle recruitment
  • negates the need for scuffing and pulling
  • drastically reduces the cardiovascular strain

As noted above, the scuffing and pulling muscles are the primary “running” muscles – meaning you minimise their use during the 54,000 movements!

If these points weren’t enough, STOMPing optimises the strongest range of movement the body can utilise (squatting with gravity, on a bike), the biomechanical range mentioned earlier.

Building strength

To become an effective STOMPer you need to have strength; to push against a higher resistance (remember the cyclist riding hill repeats, into head winds, etc). Higher resistances at lower cadences, which further lowers the cardiovascular strain.

Have you ever noticed how your heart rate and breathing rate increases when you start to “spin”? Spinning may offload the leg effort but massively loads your cardiovascular system. This uses valuable energy that you need later for the run!

We aren’t talking really slow cadences, just slow compared to the mainstream cycling, and by default, many triathlon coaches recommended cadence – 90rpm. Women should aim for 75-85, men 70-75, but there are exceptions.

Non-cycling adult triathletes that have strength to push down in a bigger gear will experience the same, or greater, overall speeds for less fatigue and strain than they would attempting to pedal like a pure cyclist. The great cadence debate2 has been around for years, but the real science behind it is nearly always overlooked.

Obsolete power formula

Now we have established that we coach our athletes to apply force through 120° at lower cadences, you can see why power training becomes obsolete.

Using this “method”, our athletes do see increases in power, equating to a faster bike split AND better run! This is because they get so much stronger on the downwards phase of the pedal stroke. Overall rhythm is not lost – the relaxing leg is STOMPed back up, removing any dead spots.

Conclusion

Pedal power is a measurement of force around 360° multiplied by speed. This may work for pure cyclists who don’t have to swim before  and run afterwards!  Bear in mind they also “feel” the pedals; they’ve been riding hundreds of kilometres every week since they could walk. TRIATHLETES don´t (generally) have this feel and also have to run after the bike is complete!

The sports are so different! Triathletes need to be more tactile, using the bike in a way that allows them to run strong. This is why we coach to build bike STOMP strength at lower cadences, so our athletes can run effectively afterwards.

Think about the sport you do and how you can sensibly achieve overall good results. A more powerful faster bike split with high cadence and run muscle recruitment will hinder the run. This, in turn, WILL result in a slower overall triathlon!

What do you really want?

References:

https://www.sciencelearn.org.nz/resources/1348-pedal-power

http://blog.trisutto.com/the-great-cadence-debate/