The biomechanics and affects of cycling on the body

One of the greatest front men of all time, Freddie Mercury, once sang “I want to ride my bicycle”. With the world on lockdown, here in the UK we are allowed out of house only to food shop and to exercise. I have noticed whilst taking a walk with my wife and 2 boys that there are a lot of people listening to the advice of Freddie and are out cycling as their chosen form of exercise.  We have seen more people cycling in our local park then we have in a long time and around the streets, it seems to be the preferred way of commuting to the store.  We are even teaching our 3 year how to cycle….good times.

Whether you are a keen cyclist or someone who pootles about town you will feel it in the glutes and legs due to the repetitive movements being used by the many muscles involved in the many joint movements it takes to cycle.

The hip

Hip Joint

The hip  is a large ‘ball and socket’ type joint which moves in multi-directions.  During cycling the hip movements include hip flexion, extension and small degree of rotation.

The Knee

Knee Joint

Then we have the knee .  This ‘hinge’ joint acts as a lever to the femur and as a fulcrum by enabling the force from the upper leg to be transferred to the lower leg. The patella is a sesamoid bone that sits within the patella tendon and connecting the quadriceps to the tibial tuberosity. The patella glides in the intercondylar fossa of the femur.

The Ankle

Ankle & Foot

The next joint we have is the ankle. This joint allows for ‘ankleing‘ – This is connected to the foot which is full of small joints but is where the main force for the lower limb is generated and transferred in to the pedal.

The foot has many small joints but primarily this is where the force that is generated from the lower limb complex is transferred to the pedal. Irregular amounts of force or compression through the foot can cause pain from compression. 

The Gluteals

The process of pedalling starts in the gluteals by taking the hip from a flexed position at top dead centre (TDC  aka Max Flexion).  As the leg extends through the drive of the leg, the quadriceps kick in to taking the knee from flexion to an extended position at Bottom Dead Centre (BDC aka max extension)

The quads

The quadriceps work in close partnership with the gluteals (maximus) and out of the 4 quads, the rectus femoris is the only muscle to cross both the hip and knee joint meaning it is used for hip flexion and knee extension.

Being seated in the saddle, muscles such as the rectus femoris can become shortened leading to anterior hip pain, but also commonly cause patella femoral pain.

The Hamstrings

The hamstrings are used for knee flexion but they also assist hip extension and stabilise the knee in BDC.

Prolonged sitting in the saddle will put compression on the ischial tuberosities which is the origin of the hamstrings, therefore compressing them.

The Calves

Then there are the calves, the gastrocnemius and soleus, and their main role is to stabilise the lower leg to enable transition of the force generated from the upper leg to the pedal.

From there, the hamstrings kick in to help flex the knee to bring it back up to TDC, and when enough knee flexion and hip flexion is achieved the hip flexors start to work again to bring the leg up to true TDC to start the cycle again.

Cycling doesn’t only place a strain on the lower body but also the upper.

Physio-pedia explains..

“There is more to cycling than the movement of the lower limbs. The trunk and back play an important role in stabilising the spine and maintaining posture. There are many muscles within the back but to name a few: Multifidi and the quadratus lumborum are a couple of the main stabilisers of the spine when undergoing lateral and rotational movements, such as right leg enters the power phase whilst the left side of the spine stabilises and vice versa. The Erector Spinae muscles also play an important part in maintaining a stable posture whilst on the bike. Abdominal muscles such as the rectus abdominus help to maintain stability as does the obliques. The obliques similarly to the back muscles will help stabilise a contralateral limb movement. As we move up the spine toward the shoulders, the latissimus dorsi and trapezius muscles enable the rider to fix their upper body onto the handlebars. The upper body has a role in stabilising contralateral torque, so as the right leg pushes down the left arm anchors to the handle bars and pulls up. Similarly with the feet, the hands can undergo sustained amount of pressure so vascularity and nerves can become injured, most commonly the ulna nerve (cyclist’spalsy) followed by the median nerve”. 

Potential injuries

So, as you have read there are many muscles involved in cycling. Any dysfunction in these muscles can lead to one or some of the cycling injuries below

Cycle Injuries [1]

What can you do to help?

Are you a cyclist? Enjoy cycling? Want to keep cylcing?  Then get in touch with us and let us help keep your muscles healthy and and joints moving to help you reduce the risk of injury.


[1] https://www.bio4me.co.za/wp-content/uploads/2019/03/Common-Cycling-Injuries.png

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