Bicycle saddle pain - cause, effect and the need for radical redesign
The conventional nosed bicycle saddle - conceptually unchanged throughout the bicycle’s history - has a fundamental design flaw that causes first discomfort, then pain and fatigue, then potentially irreversible and serious tissue damage.
Jon Catling, designer of the Manta saddle, moved from Cambridge to the Isle of Skye in 1990. ‘I went from one of Britain’s flattest parts to one of its most hilly. In cycling terms it was wonderfully liberating, but unaccustomed hill climbing and off-road tracks finally brought something home to me, literally with full force.’
The flaw is that they concentrate the rider's body weight on a very small support area, which creates point loading at one of the most sensitive and least naturally protected parts of the human anatomy.
Jon Catling: ’The saddle pain I’d just about coped with in and around Cambridge became acute on Skye. It affected me more quickly, and because pain isn’t just painful but also tiring, it became difficult to cover the distances I knew I was capable of. The problem wasn’t my bike, it wasn’t Skye, it wasn’t me - it was the saddle.’
Evidence is growing that prolonged use of conventional saddles results in significant and ultimately permanent damage to blood vessels and urogenitary organs in riders of both sexes.
This is a major concern at a time when many countries are seeing a very significant increase in the popularity of cycling for health and environmental reasons.
Jon Catling: ‘The designer in me had been mentally reinventing the saddle every time I sat on one. The catalyst to make it a serious project was the evidence just starting to emerge about long-term tissue damage caused by bike saddles. Everything I read was grim, so I decided to attempt a saddle design that went further than just reducing pain.’
Sprung, padded or larger area saddle designs
Many attempts have been made to overcome this problem by providing larger or more cushioned versions of conventional horned designs, but these are not the obvious solutions they might seem to be.
Drawbacks of a larger seating area, cushioned or not, can include poor ventilation and increased chafing of the pelvic region. Saddles cushioned by gels or liquids require an impermeable membrane that cannot ‘breathe’. Saddles with metal springs tend to be heavy. The wider the seating area, the more likely are the edges to chafe.
The main drawback of designs relying on padding or some form of sprung suspension (or both) is that by offering a perception of comfort they can mislead riders into expecting much more benefit than is delivered.
Arguably, a padded or sprung saddle may be worse for the human anatomy than a hard saddle, the pressure of which is made obvious by pain. This can be relieved or regulated to some degree by pedalling standing up or stopping for breaks.
When using a padded or sprung saddle the temptation is to sit on it for much longer, as this appears to be what it is for. But impacts from the road surface are still being continuously transmitted through the saddle to the vulnerable pudendal region. Compared to a hard saddle, pain may be dulled and so does not function as a warning signal. By journey’s end, the cumulative crushing effect on the rider’s soft tissues and arteries may be at least the same as that of a hard saddle.
Jon Catling: ‘I bought a sprung saddle that wasn’t cheap but gave it away after a few days. I was cycling 250 miles a week and knew very quickly that it wasn’t the solution. Pressure up your backside is still pressure, cushioned or not. Your body weight going one way is the same, every bump and jolt going the other way is the same. It might be numbness rather than sharp pain but the damage is still being done. Then there’s the chafing…’
Articulated lever saddle designs
Other bicycle saddle designs have used levers or ‘paddles’ to increase the support area or eliminate the point loading.
The following examples from patent literature are representative only and could be replaced by other similar saddle designs. We do not wish to dwell on the strengths and weaknesses of specific designs, except in so far as they typify a wider class of comparable designs.
Sample drawing from patent US5863094
Sample drawing from patent US4089559
Sample drawing from patent US6152524
A drawback of ‘comfort saddle’ designs that involve some movement or articulation of components is that they tend to increase the energy required at the pedals. If combined with a significantly greater weight compared to a conventional saddle, this can make them unattractive to high-mileage cyclists in particular - the very cyclists who could most benefit from reduced saddle pain.
Natural leg motion when cycling is complex, and designs with hinged but rigid paddles such as US5863094 risk failing (arguably, will inevitably fail) to follow the path of the thighs correctly. On the upward arc they have a tendency to push the thigh prematurely, which can result in rider instability at either the pedal or the saddle. It is also unlikely that the paddles will be in contact with the thighs at all times, making them somewhat hit-and-miss.
Designs based on springs consume energy and result in a loss of cycling efficiency (assuming no additional power input, for example from an electric motor). The descending thigh loses energy against the spring but the ascending thigh has less energy and support fed back into it, and so over time a significant amount of energy is wasted simply in ‘driving’ the saddle.
Designs based on levers have the potential to be more efficient than springs, but otherwise have little to recommend them. Again, articulated but rigid thigh levers cannot fully follow the natural motion of the thighs that is vital for a smooth and supportive ride. Lever mechanisms robust enough to operate indefinitely add weight, and any complexity may make them vulnerable to failure and damage. They also add height, which may reduce seat pin adjustability.
Jon Catling: ‘I bought or fabricated all the design approaches I could find that showed promise, but once on a bike they all fell short. I felt they were fighting me rather than assisting. The energy drain was palpable, ventilation was poor and the intermittent thigh contact made it difficult to have confidence in them even to keep me on the bike. They were only good for teaching me how not to design what became the Manta.’
Convention versus innovation
Despite being so detrimental to the human anatomy, the conventional nosed saddle has remained essentially unchanged and unchallenged for over a century. Reasons for its tenacity as a design perhaps include a low cost of manufacture and a perception that it ‘looks the part’ by comparison with often inelegant alternative designs.
Jon Catling:‘The Manta design looks nothing like a conventional bicycle saddle. Anyone who finds that a problem needs to ask themselves if they’d willingly watch TV, eat in a restaurant, drive a car or work a desk sitting on a conventional horned bicycle saddle. There’s no law that says it’s got to be especially uncomfortable to ride a bike. The Manta saddle is anatomically correct, while most conventional saddles are anatomically antagonistic.’
The aim of the Manta saddle project was to design a seat that allowed the rider's legs and buttocks to move freely while providing the largest feasible area of support beneath the thighs and buttocks. This would provide a much improved level of comfort relative to a conventional bicycle saddle, without any restriction on leg movement.
And ‘rider’ could also include forms of exertion by pedaling - exercise bicycles, other forms of gym equipment, pedal-powered boats etc. It’s even been suggested that drummers could benefit from a Manta seat. The possibilities may not be endless but they do go well beyond cycling.
Jon Catling: ’Essentially, the Manta is a seat rather than a saddle. It’s got almost the same body contact area as an office chair and imposes the same pressure on internal organs as an office chair - that is, none at all. It’s been described as a sofa for the bicycle and I’m not arguing with that.’
Each support lever is a rigid unit across a central pivot rail, which means that downward movement at one side drives the opposing side upward. This promotes a smooth, mutually assistive cycling action that provides continuous support for each leg.
Unlike other lever designs (see above) which can only move in a single fixed sequence, the Manta has multiple independent levers, each free to move with any body shape sitting on them. This makes the Manta design suitable for any size of rider, including children.
The rearmost support levers are fixed in relation to the pivot rail, to enhance the lateral stability of both bicycle and rider.
Each support lever is slightly raised at the centre to position the rider.
The gaps between the support levers also allow the maximum possible air flow to the thighs and buttocks legs, providing excellent ventilation - significantly more than many conventional saddles allow.
Jon Catling: ‘Right from the start I was adamant that there had to be no loss of performance or bike control. This mattered at least as much as taking away the pressure and pain. Good ventilation is important too because a cool, dry ride is a much pleasanter and healthier ride.’
The support levers are potentially replaceable with levers of different materials or dimensions or flexibility. The central pivot rail and the metal rail that attaches to the bicycle or other receiving equipment may also be replaced if necessary or desirable.
Emergence of first known zero-pressure bicycle saddle
The most significant benefit of the Manta saddle design is that it imposes no measurable pressure on the highly vulnerable pudendal regions of both sexes. This has been confirmed by independent analysis of both the design and the actual saddle, by the universities of Cambridge and Dundee respectively.
It is reasonable to claim that the Manta is the first viable bicycle saddle design not to impose measurable pressure on tissues and arteries or impede blood flow - tests suggest that the Manta bicycle saddle actually increases blood flow - and at the time of writing offers health and well-being advantages not available from other saddle designs.
Jon Catling: ‘I’ve no idea who designs nosed saddles but there can’t be a urologist among them. While prototyping the Manta design, one of the things that kept me going was very positive feedback from urologists and other medical specialists who deal every day with the often life-changing damage caused by nosed saddles. In terms of preventing pain and internal injury the Manta is a game-changer, which is why I’ll always be fully committed to it.’