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We've put together the following article which explains the bike fit acts as a real performance enhancer.

We've spend many years testing and developing our in person service alongside our online bike fitting service and along our travels we gained a huge amount of experience which has allowed us to put this article together.



We've included a discussion thread to the right so please feel free to question, argue, or berate our ideas!


Bike Fit as a Performance Enhancer

As riders, we spend hundreds, if not thousands on kit and then spend hours training at crazy times of day in all weather with the aim of being as fast of possible on the bike. But how many of us have ensured that the critical link between man and machine is as finely tuned as our training schedules and our bikes? The bike fit is a massively overlooked aspect of performance cycling; correctly fitting a rider to their bike improves power output, efficiency, aerodynamics, comfort, injury prevention and for those of us who have to, the ability to run well off of the bike.

No two riders are the same and each bike fit is unique, with no set formula to achieve the perfect fit. Scientific factors such as aerodynamics and biomechanics certainly have a very important part to play in a bike fit, but there are many other factors that vary from rider to rider. Human judgment, in conjunction with science, ensures a rider achieves their full performance potential. Factors such as flexibility, limb length ratios, injury history, technique, rider’s chosen race distance and rider’s priority between comfort and speed necessitate a very personal touch.

Angles

The aim of a bike fit is to achieve the perfect position which enables the rider to achieve optimal performance. It’s not the saddle height, saddle fore/aft position, crank arm length, frame size, stem length or handle bar position that is important, but the angles which are generated as a result of these factors which ultimately determine levels of performance and comfort.

Knee angle, open and closed hip angle, shoulder angle, elbow angle, ankle angle, foot angle, effective seat tube angle, body angle, upper arm to aero pad or handlebar angle, saddle angle - the list goes on, and changes of just a degree or two in any of these can make a huge difference to power output, efficiency, aerodynamics, comfort and more. A professional bike fitter can identify areas for improvement and allow the rider’s goals to be fully achieved.

Power

Most of us realise that losing a few unwanted pounds, whether around the waistline or from our bikes, will make us faster and for those who train and race with power, we know that improving power to weight ratios significantly improves our performances. What most us don’t appreciate is that a correctly fitted bike enables the rider to generate more power for less effort – a bike fit takes a few hours, weight loss takes a lot longer or costs a lot more.

There are many factors that effect how much power a rider can generate but a bike fit can ensure each rider is able to fully utilise their full fitness and strength. Power comes from the legs, but the legs need a solid platform enable this power generation. In running we need a strong core to power our arms and legs. Similarly, in cycling we require a strong core to act as our platform, but we also need to stabilise our pelvis and hips to use as a solid base. By setting an optimal seat position, we ensure that the pelvis does not rock and remains static. Seat height, seat angle, how the rider sits on the saddle and the saddle itself are elements looked at during a bike fit and getting these right ensures we have our solid platform from which we generate huge wattage.

Quickly digressing and looking at pedalling technique, it is widely recognised that applying torque throughout the full pedalling circle is the most efficient and powerful technique. A rider pushes the pedal down, draws the foot back across the bottom of the circle, offloads the foot on the upstroke (whilst the other leg is applying the torque), and then pushes the foot across the top of the circle. Whilst the pull across the bottom and the push over the top are not massively powerful, together they offer a substantial force and ensure the momentum is maintained prior to the powerful push down on the pedal. Employing this technique and therefore avoiding dead-spots, alleviates the energy sapping requirement to accelerate the pedals as much during the down-stroke which significantly reduces fatigue and increases power output. Identifying the cause of any dead-spots or power-limiters is key to achieving the perfect bike fit.

The human muscular-skeletal system is highly complicated and is optimised for walking and running. By asking our bodies to pedal and then by bending ourselves into aero positions we are putting unusual demands on our muscular-skeletal system and often limiting potential output.

Our upper leg muscles are very powerful and enable huge torque generation, but these muscles are optimised for a human-being operating in an upright position – walking and running. As soon as we jump on a bike and bend in two, we start to take the muscles to the extremes of their operating range. The more aero the position the bigger the problem; a time-trial position or an aggressive road position can severely effect performance by closing the hip angle, leading to dead-spots at the top of the circle and the subsequent loss of power. Changing the fore/aft seat position in conjunction with seat height can remove any dead spots, open the hip angle and allow for maximum power generation.

Pushing down on the pedals is quite natural thing for our bodies to do but the other phases of the pedalling circle and not so natural.

Pulling the foot back across the bottom of the pedal cycle requires engagement of the hamstrings, which work best with a significant bend in the knee. If our saddles are set too high, we are reducing this bend in the knee at the beginning of the pull across the bottom’ phase and asking the hamstrings to fire in a non-optimal position. This leads to a significant dead-spot at the bottom of the circle, impacting momentum and reducing overall power output.

The ability to push the foot across the top of the circle is severely hampered by a hip angle that is too closed or a closed knee angle that is too small. Seat height, seat fore/aft position and crank-arm length affect this angle and again can cause dead-spots and massively hamper performance.

Touching on technique again, in recent years it’s been recognised that rather than ‘ankling’, maintaining a fixed ankle position throughout the pedal circle is most efficient and powerful way to pedal. An incorrectly fitting bike often generates involuntary ankling and an associated loss of power. Solving this allows the big powerful leg muscles to put torque into the pedals though strong, fixed ankles whilst also reducing fatigue and starin on the smaller lower leg muscles.

Aerodynamics

The average rider spends thousands on their bike, upgrades, clothing, coaching etc etc, the list goes on. Kit is becoming more aerodynamic: frames, wheels, pedals, helmets, water bottles and even bike computers. The savings aero kit make is undeniable – an aero helmet should save the average triathlete around 6 minutes over an Ironman bike leg. But when it comes to bang for buck savings, are we missing something?

Our highly trained and shaved pink bodies create ~80% of the drag that we have to overcome to move forwards on the bike. Great savings can be made by reducing the frontal area of a rider, enabling smooth air flow over head/back and around the hips. An experienced bike fitter can really increase speed by creating an aerodynamic position whilst ensuring full power production is available.

Rider flexibility (or inflexibility) can be a huge barrier when trying to achieve optimal aerodynamics. It’s possible to assess an individual and balance aerodynamics with power production and comfort to ensure the net performance output is as high as possible.

Comfort

Every competitive rider would like to be faster but most riders would also like to be more comfortable too. Riders often have different objectives, rating the priority between comfort and speed differently. Some riders can achieve a fully comfortable position that is optimised for aerodynamics, but for most, especially those who train and race over longer distances, there is compromise between comfort and speed.

Discomfort can be a huge distraction, interrupting focus or forcing riders to sit up and lose aerodynamic advantage. It’s quite feasible than an Iron Distance triathlete could lose over 20mins due to discomfort during the bike leg that prevents them holding the aero position. Comparing this to the 6 minute saving an aero helmet could save is quite eye opening.

A bike fitter can look at a rider’s flexibility, riding style, chosen race distance and their priorities and find a balance between comfort and aerodynamics. Often, very little give is required, with only small alterations making huge improvements in comfort and maintaining very aerodynamic and powerful positions.

Saddle

The saddle is usually the most adjustable component on a bike. Fore/aft position, height, tilt, even the alignment is usually adjustable, yet very few riders realise the importance of its exact position and how the saddle can be a potential performance limiter; most see the saddle as a comfort component.

The rider should sit with their Ischial Tuberosities (sit bones) in contact with the wings of the saddle and little, if any pressure on the perineum – not doing so can impact power output. This often can’t be achieved by changing the angle of the saddle alone as it is the weight distribution across the entire fit that is key. For example, if the handlebar positioning is incorrect or the bike is set too aggressively for a rider, then pressure on the perineum often can’t be avoided without tilting the saddle so much that the rider slides forward on the saddle. Pressure on the perineum and/or incorrect saddle tilt can severely affect the amount of power that a rider can generate and the key to avoiding this is to evenly distribute weight between contact points by have all parameters set-up correctly on the bike.

Injury Prevention

A fair proportion of riders seek a bike fit because they feel their position has caused, or is aggregating an injury, but this is too late as injuries can be completely prevented with a correctly fitted bike. It goes without saying that injuries severely affect performance. Knee, hip, ITB, neck and back issues are some of the issues that can be prevented or resolved with a correctly fitted bike.

Knee injuries are the most common problem experienced in cyclists. The most common issue is the position of the saddle: height and fore/aft position. Cleat alignment, cleat float and cleat lateral displacement are other factors address during a bike fit that assist with injury prevention. Cleat position can also be fine tuned to ensure full power is available.

Overuse injuries are extremely common with riders as they increase the volume or intensity of their riding too quickly. An incorrectly fitted bike will put additional strain on the body and effectively increase the volume and/or intensity of each session. By ensuring the bike fits correctly, training volume and load can be increased at a higher rate, which ultimately improves race performance. Likewise, more can be gained from each training session if the rider is able to train at a higher output.

Fatigue

When a rider is correctly positioned on a bike, the weight of their body travels directly through their arms to their point of contact with the handlebars or the aero bar pads. By doing this, the rider’s skeleton acts as a brace to support the body, and very little energy is expended in doing this. If the bike is incorrectly set-up then the rider’s core, arms, back and shoulders have to contract isometrically to support the body and this causes fatigue, aching and unnecessary energy expenditure. We know that discomfort can effect performance, and unnecessary expenditure of energy obviously effects performance, more so as race distances increase so we can see that incorrect set-up can cause discomfort and fatigue that reduces the rider’s potential output.

Breathing

We’ve touched on this already, but an incorrectly fitted bike can lead to a closed hip angle which not only effects smoothness and power but also can close the lungs and put unwanted pressure on the diaphragm, hampering breathing and therefore performance. Some of us are guilty of not thinking about breathing in cycling as much as we should do. The performance limiting burn associated with lactic acid build up is formed when the body does not have enough oxygen to produce ‘energy’. By fitting a bike correctly and ensuring the lungs are open and the diaphragm is not restricted, we’re able to ensure maximum oxygen availability in all situations.

Bike Fit as a Performance Enhancer

“A correctly fitted bike substantially increases comfort and significantly reduces the risk of injury”. A very bold statement, yet very true and should be of great interest to every rider. If a bike fit achieved nothing else, it would still be great, but this article is entitled ‘Bike Fit as a Performance Enhancer’ and that is exactly what it is. Every rider is missing a huge trick if they have not had their bike professionally fitted. A rider correctly fitted to their bike will improve performance by increasing:

• Power Output
• Aerodynamics
• Comfort

These are three huge factors which individually can lead to substantial increases in performance. However, when considered and implemented in conjunction with each other, performance gains can be enormous. Kit costs thousands, we train for hours and hours – a bike fit takes less than half a day, is increasingly accessible, especially with online solutions, and is inexpensive. Comfort, speed and injury prevention. 

Tiger Frog Bike In-person and Online Fitting

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