An ergonomic riding position is not necessarily one that requires little muscle effort. A proper ergonomic position implies that many muscles are engaged in the effort. The work should be evenly distributed across a wide range of muscles, allowing the effort to be sustained for a long time.
With the right bike ergonomics, we pursue two important objectives:
- That the various muscles can work in the most suitable position for them: for example, thigh muscles work best when the leg is almost fully extended.
- That overloading of the neck, back and knees is avoided.
We live in a world where many of us spend too much time sitting, leading to poorly developed back muscles. A large part of us also suffers from a lack of general physical fitness, sometimes exacerbated by overweight. This latter issue is problematic for the knees. In short, bike ergonomics is an important topic if you want to enjoy a longer bike ride.
In this article, I focus on the position on a city or trekking/travel bike. Racing and MTB bikes are outside the scope of this article.
For e-bikes, the same rules apply as for conventional bikes. Naturally, physical discomfort resulting from a poor riding position will manifest more intensely and quickly on a purely muscular bike. The electric assistance on an e-bike ensures that the rider’s effort is significantly reduced.
For this article, I have based my insights on my experiences in the store and have drawn much inspiration from Julianne Neuß‘s articles on bike ergonomics.
The correct saddle height
Why is the correct saddle height important?
A saddle that is too low leads to knee problems. However, this knee pain only occurs after longer rides or after many smaller rides. One can ride with a saddle that is too low for a long time before experiencing physical discomfort from it.
On the other hand, a saddle that is too high is quickly noticeable to the rider. Typical signs include: overstretching the leg with each pedal stroke, high pressure on the genital area, and a rocking pelvis.
When the knee joint has to work at an angle less than 90°, it is the perfect recipe for knee pain. During the pedal stroke, the rider will generate power from just past the ‘dead point’ (from the left side view: the pedal arm in the direction of travel at 11 o’clock) to the point where the leg is almost straight. With a saddle that is too low, the knee will work at an angle less than 90° just past the ‘dead point’ (see image 1).
A saddle that is too low can also lead to other negative effects. When the thigh bone forms too small an angle with the upper body in the highest pedal position, the rider will compensate by tilting their pelvis backward. This flattens the natural curve in the lower back and then tilts the shoulders forward. This increases the pressure on the hands on the handlebars.
How to set the correct saddle height?
For city and trekking bikes, you can follow these steps to set the correct saddle height:
- Step 1: The rider stands upright next to their bike and positions the saddle at the height where they would wear a belt.
- Step 2: Next, the rider should sit on the bike. The pedal should be at the bottom, in line with the seat tube. The rider’s foot should be horizontal on the pedal, with the ball of the foot on the pedal axle. In this position, the rider’s leg should be fully extended without the pelvis tilting up or down. Adjust the saddle until this position is achieved.
The position of the feet while riding is an important element in striving for an ergonomic posture. The foot should be slightly extended upward while the ball of the foot rests on the pedal axle. The rider’s feet should make a slight up-and-down movement from the ankle joint with each rotation. During this motion, the rider’s heel should remain above the pedal throughout the entire revolution (see image 2).
This way, the rider’s leg length is extended by approximately 1/3 of the foot length (see image 3). When the saddle height is set according to the above steps, it results in a slightly bent leg in the lowest pedal position (see image 4).
With this foot position, the ankle joint is very mobile. When pedaling, an interaction occurs between the knee and ankle joints, which relieves the knees. With a saddle that is too low, the foot position is often sub optimal, and riding is done with the middle of the foot or even the heel. This is not surprising: Maximum power development when extending the legs occurs in the higher angle ranges, up to just before full extension at approximately 170°. To take full advantage of this, the rider instinctively adopts a posture that makes this possible. When riding with a saddle that is too low, pedaling with the middle of the foot or heel helps extend the leg somewhat in the lowest pedal position. This intuitive correction of the foot position also results in much less mobile ankle joints, which negatively impacts the knees.
Finally, when determining the correct saddle height, it is also important to consider the rider’s desired riding posture. The extension of the leg changes as one sits more upright or more forward on the bike. With the same saddle height, a more forward-leaning posture will lead to less extended legs in the lowest pedal position. The rider’s hip joint then comes closer to the saddle surface. Conversely, as the rider assumes a more upright posture, the distance from the hip joint to the saddle surface increases.
The correct horizontal position of the saddle
Only after the correct saddle height is set can the proper horizontal position of the saddle be determined.
For city and trekking bikes (*), the knee should be directly above the pedal axle when the pedal arm is horizontal and in the direction of travel (see illustration 5). It’s important that the rider correctly positions their foot on the pedal, with the ball of the foot over the pedal axle. A plumb line is drawn from the front of the kneecap downward.
If the plumb line falls in front of the pedal axle, the saddle needs to be moved backward. Conversely, if the plumb line falls behind the pedal axle, the saddle needs to be moved forward.
For shorter individuals (under approximately 1.60m), it may not be possible to achieve the ideal position with the standard cranks (pedal arms) mounted on the bike. In such cases, it is recommended to install shorter cranks on the bike.
If the ideal position cannot be achieved, it is preferable for the plumb line to fall in front of the pedal axle rather than behind it. However, the plumb line should never fall in front of the rider’s toes.
Following this knee-plumb line rule places the center of gravity of the upper body over the driving pedal while riding. This is the pedal that points forward when riding. The mass of the upper body will slightly tilt the rider’s pelvis forward and, more importantly, allows the rider to maintain this position. In other words, the knee-plumb line rule leads to an efficient riding posture that can be sustained for a long time.
A slightly forward-tilted pelvis helps the spine maintain its natural S-shape. This S-shape relieves the inter vertebral discs and allows the long back muscles to optimally stabilize the torso. This, in turn, helps reduce pressure on the hands. A necessary condition for this is that the saddle allows the pelvis to tilt slightly forward without leading to additional pressure in the genital area. If the rider experiences too much pressure in the genital area, they will automatically compensate by tilting their pelvis backward. The result is a rounded back instead of an S-shape, possibly causing excessive pressure on the hands and lower back (see illustration 6).
For the appropriate saddle choice, I refer to our blog article from 07/2024: Ergonomics on the Bike – The Right Saddle.
(*) Different rules apply for racing and triathlon bikes, which are not the subject of this article.
The correct distance between handlebar and saddle
We also need to consider the appropriate distance between the handlebar and the saddle.
In this step, we assume that the saddle height is correctly set and that the bike is equipped with an appropriate saddle that allows the rider to adopt an efficient riding posture with a forward-tilted pelvis and an S-shaped spine (see image 7). The rider’s center of gravity will then be above the driving pedal, ensuring that the supportive counter forces from the handlebar and saddle are minimized during intense effort.
The distance between the saddle and the handlebar should be set so that a right angle is formed between the upper arm and the upper body (see also image 7). This way, the counter pressure is directed towards the strong shoulder and chest muscles, and not towards the more sensitive neck muscles.
The height of the handlebar should allow the hands to rest on it with relaxed shoulders. This rule is often violated. With too much pressure on the hands or neck pain, many cyclists intuitively think that a higher handlebar position will provide relief. However, this is a false reasoning. In their pursuit of efficiency, the rider will shift their center of gravity forward during effort. A handlebar position that is too high will inevitably lead to excessive counter pressure from the handlebar. The result is still pain in the hands and raised shoulders. The rider will then compensate for this by rounding their lower back (see image 8&9).
Paradoxically, the correct answer to too much pressure on the hands is often a greater distance between the saddle and the handlebar and/or a lower handlebar position (see image 10) (this is assuming that the saddle height is correct and the knee-plumb line rule is respected).
Finally, a brief note on the appropriate width of the handlebar. From the MTB world, we see the introduction of very wide handlebars. Our experience shows that for city and touring bikes, a wide handlebar has no added value. We advocate for a handlebar that is just slightly wider than the rider’s shoulder width.
Desired vs. Achievable:
Experience teaches us that the recommendations mentioned in this article are not feasible for everyone. Many of us spend too much time sitting, which naturally affects the fitness of the body: insufficient abdominal muscles, shortened thigh muscles, inflexible hip and knee joints, a rigid spine, etc.
In the store, we often must find a compromise between what is possible for the rider and what is desirable according to the earlier mentioned ergonomic rules. Of course, every step towards a better ergonomic riding position is a step in the right direction. However, it is important to realize that if one fails in adopting a fully ergonomic position on the bike, one is essentially riding in a position that can lead to physical discomfort.
The rise of the electric bike helps in this context. The electric motor supports the rider. When going uphill, it is often enough to ask for more support from the motor to climb the hill with equal effort. In other words, adopting an efficient riding posture (center of gravity of the upper body above the driving pedal) becomes less important on an e-bike. Since the e-bike rider exerts significantly less physical effort, possible physical discomforts due to a poor posture will manifest less quickly and less intensely. Therefore, you can still experience knee pain on an electric bike if the saddle is not set correctly, but it will take longer for this discomfort to be felt.