An Ironman Machine.

The cogs and wheels of a bike are plain to see, but the components of human muscle are much less clear. A little background biology and some time invested in bike set up can help you towards faster, more comfortable cycling. There are consequences of the speed at which you pedal and the gears you use that can affect your race day performance. Your position on the bike can also improve your training and racing, whilst gadgets like tri-bars can see your splits shrink.

How Do Muscles Work And Why Does It Matter To A Triathlete?

A detailed knowledge of sports physiology may not seem like the fastest way to a new PB, but if you understand how your body works, you are in a better position to fine-tune it through training effectively than someone who is blindly powering through junk miles. We’ll start with the body tissues that get you up in the morning; muscles.

Muscle contraction has a widely accepted explanation in modern biology. The model known as the sliding filament theory describes a molecular motor that moves against another stationary protein following the release of several chemicals that is initially triggered by nerve impulses. The motor protein, known as myosin, pulls against a framework of another protein, actin.

One of the most important properties of muscle with regards to triathlon is the optimum length of a muscle.  The muscle filaments overlap the most in the middle of a muscle’s working range. When a muscle is extended fully some of the molecular motors have no grip on the proteins they usually pull themselves along. When a muscle is fully contracted, the motor proteins start to contact with nearby structural proteins and so movement is hindered. It is this middle ground in muscle length that bike fitting specialists aim for when setting up a bike. Within the range of movement the limb must extend enough to generate a powerful crank pushing force, but not to the extent that the muscle loses power by being overstretched. The links below will route you to detailed pages of advice on setting up your bike correctly, or get your bike set up professionally by a company such as our sponsor: Bike Science

Setting up your bike may take some time,  money and some careful thought, but if you bear in mind that during a 2 hour training ride averaging 100 revolutions per minute your repeat the pedalling motion 12000 times, it is surely worth getting it right in order to stay injury free.

Further Information On How To Set Up Your Bike

A step by step guide to adjusting just about everything on your bike

http://www.andoverwheelers.com/Documents%5CErics_bike_set_up_instructions.htm

Triathlon specific information about bike set up

http://www.slowtwitch.com/mainheadings/techctr/bikefit.html#Anchor-BASICS-49575

---

Cadence

Cadence is the number of revolutions of the cranks per minute, when referring to cycling, though cadence is sometimes used in reference to swimming and running. The gears on bikes allow the possibility of maintaining the same speed either by pedalling quickly in a low gear and pedalling slowly in a high gear. This raises the question: Is a higher or a lower cadence better?

One way to answer this question is to consider the clearance of the chemical waste our body makes. Roughly speaking, high intensity work that can only be maintained for a short period of time, like pedalling in a high gear or a burst uphill, is termed “anaerobic” because the body does not use oxygen to release the energy needed for it. The result of this is the production of a chemical called lactic acid, or lactate, which causes the burning sensation you feel when you work hard in a high gear or uphill for anything longer than a minute or two. Gears can be used to lighten the load on the muscle, reducing the intensity of each pedal stroke makes the activity more aerobic, i.e. the oxygen demand is met and less painful lactic acid is produced. The general principle that many pedal strokes on a lower gear produces less lactic acid than fewer strokes on a higher gear without sacrificing speed, is most likely the one that led Lance Armstrong to adopt a higher cadence riding style that won him the Tour de France seven times.

Before altering the cadence you ride at you need to measure your cadence. You can use a cadence meter fitted to your bike or you can simply count for 30 seconds and multiply by 2 to calculate the number of crank revolutions per minute. The first article on cadence referenced below takes 90 rpm to be a typical speed, and so if you cycle at around this or lower, you could look at pedalling closer to 100 or more rpm in a lower gear and see if you can go further at the same speed.

Further Information On Cadence

More detail on what training at different cadences can do for you.

http://www.raf.mod.uk/raftriathlon/rafcms/mediafiles/498B1498_1143_D71E_469F6513AD1643D5.pdf

This page is aimed at tour cycling, but has useful data tables about gearing and speeds on different terrains.

http://www.kenkifer.com/bikepages/touring/gears.htm

---

Aerodynamics: What’s Stopping You?

The invention of  tri-bars (also known as aero-bars) revolutionised cycling and now modern time trial bikes are light-weight machines with high-tech aerodynamic shapes to rival commercial jet planes. These bikes along with the triathletes drive to cut times means we are forever searching for ways to minimise air resistance on the bike. Hence if you haven’t already adopted an “aero” position, you will most likely have seen someone with arms in tri-bars, leaning heavily forward with knees brushing their chest.

If you are interested in changing the way you ride there are two types of tri-bars. You can adapt a road bike with clip-on bars or purchase fixed bars either with a bike or separately. These can cost anything from £30 to £150 usually and require an Allen key and take a few minutes to fit. Many time trial bikes come fitted with tri-bars built into the handlebar.  These handlebars are available separately, and so for a few hundred pounds any road bike could be fitted with aerodynamic handlebars. Clip-on bars can be prone to slipping if not set up correctly, whereas fixed bars do not have this problem. Fixed bars also tend to be more aerodynamic themselves, whilst a clip-on set up offers the rider the same body position as a time trial handlebar, it is likely to be less aerodynamic than the space aged wing shape seen on time trial bikes.

It is important to have the tri-bars positioned correctly to ensure you are actually reducing the air resistance you have invested money in eliminating and riding in away that will minimise your risk of injury. It is therefore best to consult the manufacturers instructions, perhaps a local cycle shop. You may also find the video at the link below useful. The clip features 6 time world Ironman champion Dave Scott advising on tri-bars and bike position. As it is midseason at the time of writing, it may be worth bearing in mind that tri-bars are much less stable during steering than a standard bike set up and adjusting to an aerodynamic position can cause soreness and stiffness particularly in the upper back and neck. Changing your riding style should always be done gradually, and tri-bars are best used in training first, not just stuck on fresh out of the box on the morning of a race.

Dave Scott’s Advice On Aerodynamic Positioning

http://www.youtube.com/watch?v=RJlBXFMZLnw

Related posts:

1. Product review: Planet X – Exocet Time Trial Bike There’s an old adage in triathlon that says don’t try...
2. Retul Bike Fitting at Bike Science: Taking away the guess work In the past, a bike-fitter’s work was mostly art. His...
3. Triathlon Gear: Kettler ErgoRace training bicycle A home exercise bike used to be something your parents...
4. Triathlon training: another way to defeat the turbo Last week we noted the power of imagination and distraction...
5. Triathlon training: Try a Trixter VRX-Biking class VRX-Biking is indoor cycling with a difference: the bike has...