Bike fitting 101 – How a Simple Bike Fit Adjustment Solved Neck Pain, Saddle Sores and Back Pain

Cycling should feel smooth, efficient and enjoyable. But when your bike setup isn’t quite right, small issues can quickly turn into persistent pain.

At Kernow Physio, Scott Tomkinson regularly works with cyclists who are struggling with discomfort on the bike — from neck and back pain to saddle sores and hip restriction. The good news is that many of these problems can be solved with the right combination of physiotherapy insight and professional bike fitting.

In this recent bike fit session, Scott explains how a few carefully considered adjustments transformed one rider’s comfort and efficiency.

The Problem: Pain During Riding

This particular rider came to Kernow Physio experiencing several issues while cycling:

• Persistent back pain
• Saddle sores
• Significant neck tension and discomfort

After riding for around an hour, the rider’s neck would become tight and painful, making longer rides difficult and uncomfortable.

As with many cases, the root cause wasn’t simply the bike itself — it was the relationship between the rider’s body and the bike setup.

Understanding Body Position on the Bike

One of the key concepts Scott looks at during a bike fit is Body Mass Representation (BMR).

In simple terms, this represents the centre of the rider’s body. Ideally, the body’s centre of mass should align correctly with the bottom bracket – the central point where the pedals rotate.

When this alignment is off, the rider’s body has to compensate.

In this case, the rider’s BMR was positioned too far forward of the bottom bracket. This caused several knock-on problems:

• Excess strain on the neck and upper trapezius muscles
• Increased pressure on the saddle
• Inefficient movement patterns while pedalling

The Role of Hip Mobility

During the physiotherapy assessment, Scott also identified restricted hip mobility.

Because the rider couldn’t comfortably clear the hip at the top of the pedal stroke, the knee movement was forcing the pelvis to shift left and right while pedalling.

This instability was a major contributor to the rider’s saddle sores and discomfort on longer rides.

The Solution: Small Changes, Big Difference

One of the fascinating aspects of bike fitting is how small adjustments can have a huge impact.

In this case, Scott made a few targeted changes:

• Shortened the stem by 20mm
• Lowered the stem position
• Lowered the saddle by 10mm
• Improved the rider’s core engagement and sitting position

These adjustments repositioned the rider so that their body mass aligned correctly over the bottom bracket.

The result?

• The pelvis became stable
• The rider was now sitting properly on the sit bones
• Core muscles engaged naturally
• The shoulders relaxed
• Neck tension disappeared

All from a few carefully considered changes.

Bike Fitting Is More Than Just Adjusting the Bike

A proper bike fit isn’t just about moving components.

At Kernow Physio, Scott combines physiotherapy knowledge with cycling biomechanics, looking at how the rider’s body moves and functions as well as how the bike is set up.

This approach helps identify issues such as:

• Mobility restrictions
• Muscle imbalances
• poor posture
• inefficient movement patterns

By addressing both the rider and the bike, the outcome is far more effective.

Why Professional Bike Fitting Matters

Whether you’re a competitive cyclist, club rider, or someone who simply enjoys exploring Cornwall’s roads and trails, a professional bike fit can help you:

• Prevent injuries
• Ride more comfortably
• Improve efficiency and power
• Enjoy longer rides without pain

As Scott often explains, bike fitting isn’t complicated science — but understanding how the body interacts with the bike is crucial.