What is ergonomics?
A sore bum, a burning back, numb toes, cold hands and a neck that no longer wants to carry your head - the time spent in the saddle has increased significantly for many people in recent years. Cycle tourism, e-bikes, environmental awareness, permanent traffic jams, the fitness craze and, last but not least, petrol prices have all contributed to this. For some, however, this is accompanied by minor or major ailments that cycling brings with it. You just have to get through it ... Wrong!
Sitting, pedalling and Lnking may be strenuous, tiring and perhaps not a natural movement, but nobody has to simply accept pain, especially not at the points of contact with the bike: saddle, handlebars, pedals. Ergonomics experts are concerned with these interfaces between man and machine. By improving the components on the bike and intelligently positioning the rider on the bike, they try to harmonise the interaction between man and technology in such a way that as little energy as possible is lost, a healthy form of movement is created and nothing stands in the way of a pain-free ride.
DIY bike fitting?
When it comes to adjusting your riding position, you have a choice: in a specialist shop, with a bike fitting specialist or on your own at home. The process and parameters are roughly the same in all cases: saddle height, saddle angle, position of the saddle in relation to the bottom bracket, distance of the handlebars, cant of the handlebars, alignment of the cockpit, positioning of the foot on the pedal. Of course, an expert such as Dr Kim Tofaute from the manufacturer Ergon can respond better to individual questions and circumstances, not every store has the full expertise here, specialists are not cheap.
Tip: If you want to "fit" yourself - Ergon offers a toolbox for 30 euros with all the necessary do-it-yourself tools, templates, tables and clear instructions to help you find at least a basic set-up for any type of bike. Our other experts SQlab and Ergotec also offer measurements and fitting at their respective authorised dealers.
Three contact points, one driver
Limiting the topic of ergonomics to the components saddle, handlebars and pedals would not do it justice. As Dr Kim Tofaute, bike fitting specialist at Ergon, one of the pioneers of ergonomic bike products, confirms, good sitting, pedalling and bike control start with the right bike and its geometry. No upgrade in the world can make up for a completely bad purchase. And although new bikes are generally specified by their frame height, length plays a much more decisive role in ergonomics. The distance between the saddle and handlebars defines the angle of the upper body to the pelvis and therefore also the weight distribution on the bike.
Although it is not per se unhealthy or fundamentally uncomfortable to sit leaning forwards in a sporty position, the less time you generally spend in the saddle, the more likely such a bent hip position is to cause pressure pain in the hands and pubic bone, and the neck and back will burn due to the greater effort required to hold it.
The right sitting position
Dr Achim Schmidt, a lecturer in cycling at the Cologne Sports University and a racing cyclist himself, therefore advises that anyone who rarely cycles and only short distances should choose a completely upright sitting position, such as on a Dutch or city bike. This comes closest to the natural posture when walking and you don't have to strain yourself as much with adjustment processes.
In addition to pneumatic tyres, the biggest developments in terms of comfort and ergonomics since the first wheels have been the ball-bearing steering and the saddle in its modern form.
However, the more often and, above all, the longer you cycle, the more important the efficiency of your riding position becomes. The correct saddle and handlebar height and corresponding upper body position, the support angle of the arms and positioning of the feet on the bike then become more important - and therefore generally also sources of error and problem areas. Based on his gut feeling, sports scientist Schmidt would change the riding position of a good half of the cyclists he encounters; in most cases, they are sitting too low and too elongated for their physical condition.
Rule of thumb: If the upper crank arm is parallel to the frame tube between the bottom bracket and saddle (seat tube), the leg on the other side should be fully pushed through with the heel on the pedal.en. Bhen pedalling over the ball of the foot, there is always a minimal bend in the knee, even over the bottom dead centre. This is the biomechanically best and healthiest way to sit. If you feel insecure, you can sit a little lower; if you can place one foot flat on the ground, you are definitely sitting too low!
Ergonomics on your own body
Max Holz, Head of Development at SQlab, together with Ergon and Ergotec the full-range supplier among the ergonomics experts, takes a similar view. The bike, or more precisely cycling, is not in the human genes, so less experienced cyclists simply lack the feeling for the "right" way to sit. The biomechanics graduate and former World Cup mountain biker sees room for improvement in nine out of ten people, half of whom he even speaks of as potential problem cases. But the bike does exist, as a hobby vehicle, sports equipment or means of transport, and with targeted adjustment of the contact points, most people can enjoy cycling again.
Ergonomics experiment: travelling to Paris by trolley
An interesting experiment in this context took place between Mannheim and Paris in 2018. Using replicas of the 200-year-old draisine, the first running wheel and forefather of all bicycles, expert Schmidt and his university colleague Frank Hülsemann attempted to cover the 200 kilometres by walking and running respectively. Given their fitness and the biomechanical advantage of not having to carry their weight, this was actually an achievable task in three days. However, sitting on her legs and moving them at the same time proved to be a painful compromise. The wide "seat beam" padded with horsehair and leather forced both of them to walk with their legs spread outwards, while the natural gait places the feet exactly under the body; the faster you walk or run, the more the footprints are in line.
Schmidt: "It was like jogging, but with a crate of drinks between your knees!" Why this digression? Mainly to illustrate the balancing act that ergonomics has to perform in cycling. The saddle has to support the pelvis and therefore the majority of the rider's weight, but at the same time must not interfere with the up and down movement of the legs. As if that wasn't difficult enough, the human anatomy offers the saddle relatively few and small points of contact. The pelvic bone is V-shaped, leaving only two solid contact points with the surface area of a crown cork. No matter how wide, strong, narrow, trained or latent a rider's bum is, the soft parts of the bum carry almost no body weight.
Self-experiment: Place a piece of corrugated cardboard on a hard seat and actively pull your pelvis downwards into it. The resulting impressions correspond to the size and distance of the pelvic bones.
Pelvic ergonomics in pictures
"Bottleneck" saddle
The construction of the saddle is a bit of a negative to that of the pelvis. The rear part is wider as standard to support the sit bones. In order to reduce the localised pressure here, the surface can be padded, but beware: the deeper you sink into the padding, the more the material presses against the back and inside of the thigh. This not only takes a little effort with every pedal stroke, but the friction and pressure points can become sore or even painful as the ride progresses. There is a reason why racing cyclists use very narrow models despite spending six to seven hours in the saddle. It has nothing to do with weight or aerodynamics. Added to this is the fact that large, important blood vessels run along the inside of the legs.
Extremely thickly padded saddles with corresponding pressure on the flanks can impair blood circulation. If you generally get cold feet when cycling - this could be the cause. Max Holz from SQlab confirms from his experience that there are rarely direct causal chains between symptom and cause, so the pain and the reason for it do not always have to be localised in the same place, as in the example above.
Which saddle for which ride?
Older bikes often still have saddles with a strongly curved seat surface at right angles to the direction of travel. If the two bony contact points do not rest on a horizontal surface, this very often results in pain and burning in the depths of the pelvis. This is because the rider's weight presses down on the two sit bones and this force is redirected outwards on a curved contact surface, as if you were supporting yourself with your hands on a ball. However, the pelvic bones are not fused together, but are held together by ligaments and muscle tension. If the body weight pushes the two sides apart due to the saddle shape, there is a constant pull on these areas. From all this follows: The two lower ends of the ischial bone should rest on a flat, not excessively padded surface; paradoxically, the longer and sportier the rides, the narrower the saddle should be cut. Measuring the ischial distance is therefore the first step in finding the right saddle.
The vast majority of models on the market are much narrower towards the front. If we recall Dr Schmidt's problems on his draisine, it becomes clear why. The legs should pedal up and down as close to the wheel as possible so that the knees follow the natural axis of movement as when walking or running. Sitting on the bike like a "cowboy" with your legs rotated outwards, as Kim Tofaute calls it with a wink, is not only tiring, but is also not good for the musculoskeletal system in the long term. The saddle nose or saddle horn, as the front section is called, is designed to support little or no weight, depending on the position of the upper body.
On the one hand, it prevents you from slipping off the saddle, but much more important is its function in guiding the bike. Even with both hands firmly on the handlebars, the bike is also steered with the thighs; without the saddle nose, the system would become highly unstable at the latest when signalling a change of direction.
Problems with blood circulation
The difficulty: depending on how low the upper body should tilt and how flexible the person is, the pelvis also rotates forwards and the load on the sensitive parts increases. The area in front of the ischial tuberosities is not bony; on the contrary, there are sensitive soft tissues with a strong blood supply in this area. as of all genders. Simply increasing the surface area or padding it thickly would have the same effect as with the trolley.
SQlab carried out a study in which male test subjects had to pedal on a cycle ergometer and various saddle concepts, while the oxygen saturation in their genitals was measured at the same time. The somewhat alarming result: with most saddle concepts, the supply fell below 25 per cent, in a few cases even below five per cent. Depending on the duration, this could not only lead to numbness, but even to impotence disorders, according to SQlab developer Holz.
Conclusion on the saddle
Roughly speaking, there are three proven saddle concepts to combat these devastating figures plus one or two promising approaches. All have their justification, and it's hard to say: this saddle is the best! Saddle, riding position and bum simply have to fit together, but with ergonomic saddles the likelihood of making a mistake is much lower, whereby product selection and wheel adjustment always go hand in hand. Tofaute speaks of the "three pillars of cycling fun": the right material, the correct setting and an adapted physique, i.e. physical familiarisation and a certain level of fitness. According to him, half of the typical problems can be solved by correcting the position or replacing ergo parts.
Saddle concepts and pressure distribution
Everything under control
The fun triad also applies to the handlebars. As with the saddle, the individual position on the bike has a direct influence on potential problems. The most obvious are, of course, those directly on the hands. Depending on the sportiness of the bike, up to 40 per cent of the total weight is on the front wheel, so the slightly lower support load on the handlebars should not be underestimated, but: With a well-adjusted sitting position and a little body tension, this effort is greatly reduced, professionals can even ride freehand in a racing position!
On touring, trekking and city bikes, hand pain is rarely caused by high support loads, but rather by incorrect hand posture. The evolutionary transformation of the hand into a gripping tool has created a very sensitive transition between the hand and forearm, which only remains problem-free in a straight position. The correct hand position can be determined using the "luggage method": In the position in which you would carry a heavy suitcase, the wrist should also point towards the handlebars. However, most cyclists intuitively support themselves on round handles with the palm of the hand between the crook of the thumb and the base of the little finger rather than the ball of the hand, so that the pressure of the arm pushes the wrist "past the handle" downwards into a final position that affects the nerves and blood vessels.
The wrist position
The right handlebar grip
In addition to regular self-checking, ergonomic grips that are flat rather than round and force the hand into the described position help here. An additional slight curvature towards the rider that fits exactly into the natural, hollow shape of the hand is also clever here. Laterally bent wrists are more typical on mountain bikes with their very wide handlebars or on Dutch bikes with handlebars that are strongly cranked towards the rider. Pain in the joint space on the thumb side or along the edge of the hand on the little finger side are typical symptoms here. Ideally, you should make sure that the rider, stem length, handlebar height and width as well as handlebar bend are compatible when you buy the bike, because replacing parts is more time-consuming and expensive, and changes can also affect the riding physics of the bike. This is where we really recommend the help of a specialist.
Handlebar setup tips
However, there are a few basic rules or guidelines for DIY riders when it comes to setting up the handlebars:
- Viewed from the side, the angle between your upper arm and upper body should never exceed 90 degrees, otherwise you will be sitting stretched out far too long.
- Regardless of the angle or type of bike, the back should form almost a straight line from the rump to the back of the head. Frames and stems that are too short feel good in the short term, but the resulting hunchback forces the cervical spine to bend backwards violently, which guarantees neck pain.
- For sporty riders, the front wheel hub should be hidden from view by the handlebars; the more comfortably you sit, the further the front axle "moves away" from the handlebars. It should never be visible in the direction of travel beyond the handlebars, at least when seated.
- As your elbows should always be slightly bent when riding, you should also approach test rides and fittings in the same way.
- When shifting your body weight from the handlebars to the saddle by swapping parts or adjusting the stem, your hands should not move behind the vertical axis of rotation of the handlebars, as this changes the handling of the bike; the bike needs a little weight on the handlebars for good directional stability.
>> Tip: Handlebar models with several grip options or croissants effectively prevent premature fatigue.
Ergonomic parts would only make limited sense on new bikes, as each one has to fit individually like shoes. This is why manufacturers often only fit them with standard components.
The next generation of ergonomics
Pedals have not been considered in the context of ergonomics for quite as long. Technically, they only consist of a platform with a bearing-mounted axle. Bike expert Schmidt from the Cologne Sports University has observed that a surprising number of pedals and cranks no longer run on a circular path in the direction of travel due to falling or toppling over, but rather run at an elliptical angle to the outside or inclined to the circular path.
The most common "mistake" we observe in this regard is placing the feet in the metatarsal area, not on the ball of the foot - often seen in combination with knees rotated far outwards - is the result of a saddle position that is too low. Men in particular often find it practical to hook the heel onto the pedal. Her pomus muscle is also often shortened, which is responsible for the external rotation of the leg, among other things. The counterpart on the inside of the leg, on the other hand, is too inactive, as expert Tofaute knows.
The foot position
The correct pedalling movement
But what is the correct pedalling movement or the correct ergonomics when pedalling? To find out, we return to Max Holz and his theory that cycling is not a natural movement programme. You don't roll like you do when walking, you don't have to lift your body, and your feet are virtually fixed and not free during the entire cycle. This makes how you position your feet on the pedals very important, and not just for your feet. Their alignment continues upwards through the knees into the hip joints and thus the torso.
To use the comparison with walking again: Although the entire foot is placed on the ground, the actual footprint is made with the ball of the foot. This zone is designed to transfer pressure, whereas the area behind it, the high longitudinal arch, is not. On its underside there are no bony contact surfaces under the skin, but a series of taut tendons that do not touch the ground at all during a healthy barefoot gait and do not like pressure from below. That's why the forefoot should be on the pedal, or more precisely, the ball of the big toe should be exactly over the axis of the pedal.
>> Tip: If the soles of sports shoes are too soft, for example, the axle or frame of the pedal can press deep into the material and create very punctual pressure. Firmer soles are better, at least for longer distances, and special cycling shoes even have a fully stiffened sole for precisely this reason.
Pedalling round - like an engine
Because special cycling shoes make little sense on everyday bikes, ergopedals compensate for this with larger, flat pedal bodies; some models are also slightly concave, i.e. curved downwards, so that the foot slides into the correct position almost automatically. An edge on the inside also helps the rider to place their foot as far inwards on the pedal as possible without running the risk of colliding with the crank. As mentioned, the biomechanically ideal pedalling position is as close to the bike as possible, which applies to both the feet and the knees. The compromise between ideal and comfortable lies in the Q-factor, i.e. the lateral distance between the pedal body and the centre of the bike at hip width.
Foot position and pedals
Thanks to the ergopedals, some of which are available with different axle lengths depending on the rider's habitus, the feet are already correctly positioned and it is now only up to the rider to keep their knees as close to the bike as possible. A visual aid: An imaginary thread, attached to the tip of the knee with a weight, should dangle over the centre of the foot for the entire rotation of the cranks. Lateral deflections in the knee would irritate this hinge joint in the long term - or worse. Okay, the comparison with the motor is not one hundred per cent accurate, because not all human "components" are arranged at right angles to each other.
As can be seen in the sketch of the interplay between foot and pedals, the natural foot position is not completely straight forwards; the two feet form a slight V of around 15 degrees. Ergonomic pedals also take this into account; the leading edge on the inside is aligned exactly to this angle. From the summer, SQlab will even be offering a pedal with a slightly rotatable tread surface, which in turn should prevent tension in the knee and foot.
Inlays
If the saddle and pedals have already been replaced and the riding position has been optimised professionally or using a do-it-yourself method, but your feet and/or knees still sting or burn, this may be due to overloaded or cramped soles of the feet as a result of misalignments, and sometimes also due to suboptimal pedalling movements with too much force and too little frequency. Insoles are a relatively inexpensive way to optimise ergonomics. Some cushion pressure points, others support the arch of the foot, most of them stiffen the sole of the shoe. In our opinion, however, the greatest benefit lies in the correct positioning of the foot over the pedal, and this is specific to cycling.
Insoles designed for running or hiking do not help here. Like an adapter between the foot and pedal, they tilt the foot into a position that enables a direct, straight flow of force from the knee via the shin to the pedal axle. The muscles around the ankle that are responsible for this tilting when walking quickly become tired due to the high force applied when pedalling, which is usually where the burning sensation comes from.
It pays to focus on ergonomics when cycling
Conclusion: When an ergonomics expert like Kim Tofaute is still amazed after thousands of measurements at how minimal changes to the bike set-up can make a huge leap in riding comfort and bring a smile back to the rider's face, it shows that it is worthwhile for everyone to look into the subject of ergonomics and bike fitting.
100 km pain-free
That was a lot of theory on the subject of ergonomics - it all sounds great, but it also has to prove itself in practice. And that's exactly what we'll be doing with one of our readers in the next issue. The cycling novice responded to an appeal from MYBIKE and has already been fitted to her new bike down to the last millimetre by fitting specialist Dr Kim Tofaute and his Ergon team - or rather, the bike has been fitted to her. Her challenge will be to complete a 100-kilometre tour after a short familiarisation phase - a real feat of endurance for a newcomer with an expected net riding time of around five hours. We will be following the experiment and will of course report on whether the bike-fitting measures have worked as expected. More in issue 4/23.
