## 1 Introduction  
Despite city and commuter bicycles being marked as \"comfortable\", numerous users report dissatisfaction with the riding position, discomfort, difficulties in steering, and frequent experiences of pain and numbness associated with cycling [1, 2, 3]. Cycling is generally regarded as a sport with great potential for fitness and rehabilitation, with the added value of not being associated with repetitive joint impact [4]. However, despite these perceived benefits, there are significant concerns related to discomfort and health issues among cyclists. Cycling is widely seen as a gentle exercise that helps people with knee osteoarthritis (OA) and other long-term muscle and joint problems [5; 6]. Its smooth, repetitive movements reduce joint stress, making it a good choice for knee OA recovery while improving joint movement and strength [5; 7]. A review of common cycling injuries highlights that symptoms such as pain and numbness, although not immediately health-threatening, can significantly impact a cyclist's overall health [8]. This is particularly relevant for the perineal region and lower back, with LBP being a critical concern due to its popularity and impact on daily activities. Cycling, while beneficial, has not been proven to prevent LBP and is less effective than alternative interventions for reducing disability [8]. This may be attributed to the suboptimal setup of bicycles, which can exacerbate discomfort and pain [8]. Furthermore, the knee joint is one of the most affected body parts in cyclists, with knee pain or injuries ranging between 14.8% and 33% among those involved in long-duration pedalling [9]. Other body sites also contribute to the discomfort and pain experienced by cyclists. The epidemiological significance of LBP, which demands attention, underscores the importance of addressing these issues to improve cyclists' overall health and well-being [10]. While cycling remains a popular fitness and rehabilitation activity, the associated discomfort and risk of injury, particularly to the knee and lower back, warrant careful consideration. Ensuring an optimal bike setup and addressing common injury sites can help to mitigate these risks and enhance the cycling experience. Although some symptoms may not be immediately health-threatening, they have the potential to significantly affect one's health, particularly in the perineal region (cyclist's syndrome) and lower back. The bike-fitting industry has advanced significantly, incorporating various technologies and methodologies to optimise cycling performance, comfort, and injury prevention. Recent bike-fitting advancements have also introduced biomechanical-based technologies to address the diverse needs of cyclists. These technologies consider biomechanical factors such as joint kinematics, pedal forces, pressure mapping, and muscular activity to optimise the cycling position. These innovations aim to enhance performance while preventing overuse injuries and improving comfort for cyclists across different cycling disciplines [11]. Systematic reviews of bike-fitting applications emphasise the importance of optimising riding positions to improve bike-user compatibility, comfort, and injury prevention. Studies have underlined the need for individualised bike fitting conducted by experienced professionals familiar with the biomechanics of cycling [11; 12]. The variability in advice provided by different bike fitters underscores the need for data-driven bike-fitting methods. Research has shown that subjective expert fittings can vary significantly, with differences of up to 3 cm in saddle height and setback. Implementing data-driven approaches can help to standardise fitting practices, ensuring consistency and accuracy [12]. The needs of competitive cyclists differ significantly from those of urban cyclists. While performance-oriented cyclists often prioritise efficiency and power transmission, urban cyclists require a fitting that emphasises comfort and injury prevention.