Four times more efficient than walking - and this summer is the perfect time to try it

You're at your front door, facing a daunting three-mile journey to work. You don't have your car and there's no bus service.

You could walk for an hour - or hop on your bicycle and get there in just 15 minutes, without even working up a sweat. You opt for the latter. Millions of others would make the same decision. It's estimated that over a billion bikes exist worldwide.

According to The Conversation, cycling is one of the most energy-efficient modes of transport ever created, enabling humans to travel quicker and further while using less energy than walking or running. But why does pedalling feel so much easier than pounding the pavement?, reports the Express.

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The answer lies in the sophisticated biomechanics of how our bodies engage with this two-wheeled wonder, with Transport for London even announcing a new £2.2 billion tunnel under the Thames complete with a free shuttle bus specifically for cyclists.

A beautifully simple machine

When we walk or run, we essentially fall forward in a controlled way, catching ourselves with each step. Our legs must swing through large arcs, lifting our heavy limbs against gravity with every stride.

This swinging motion alone uses a lot of energy. Imagine: how exhausting would it be to continuously swing your arms for an hour?

When you're on a bike, your legs go through a significantly smaller, circular motion. Rather than moving the full weight of your leg with each stride, it's a case of rotating your thighs and calves in a compact pedalling cycle, which saves energy almost immediately.

Yet, it's the way bicycles convert human effort into moving forward that marks out their true efficiency. When walking or running, there is a mini collision with every step you take.

This can be both heard in the slap of your shoe against the pavement and felt as vibrations through your frame – this represents an energy loss, manifested as sound and heat via your muscles and bones.

Moreover, walking and running inherently incorporate another form of inefficiency: every step slightly brakes you before pushing off again. When your foot lands in front, it generates a backward force, briefly slowing you down, thus requiring your muscles to double down and get you moving once more.

In contrast to landing with a thud, cycling ensures a smooth rolling contact, where the tyre tenderly "kisses" the road and lifts off. The result?

Barely any energy is squandered upon impact

Plus, with the wheel’s rotation being so seamless and the force acting upright upon the terrain, you bypass that halting, braking motion altogether. Your pedalling power gets directly translated into pure forward momentum.

However, bicycles also optimise our muscle performance. There's a basic limitation in human muscles: the faster they contract, the weaker they become and the more energy they use.

This is known as the force-velocity relationship of muscles. It explains why sprinting feels much more strenuous than jogging or walking - your muscles are operating near their speed limit, becoming less efficient with each stride.

Bicycle gears provide a solution to this issue. As you increase your speed, you can shift into a higher gear, allowing your muscles to maintain their pace while the bike accelerates.

Your muscles can remain in their optimal zone for both force production and energy expenditure. It's akin to having a personal assistant constantly adjusting your workload to keep you at peak performance.

Walking sometimes has the upper hand

On particularly steep inclines of more than about 15% gradient (meaning you ascend 1.5 metres for every 10 metres travelled), your legs may struggle to generate enough force through the circular pedalling motion to propel you and your bike uphill. We can exert more force by extending our legs straight out, making walking (or climbing) more effective.

Even if roads were constructed, we wouldn't be cycling up Mount Everest.

The situation is different when it comes to downhill travel. Cycling downhill becomes progressively easier (eventually requiring no energy input), whereas walking down steep slopes actually becomes more challenging.

Once the gradient surpasses roughly 10% (it descends by one metre for every ten metres of distance), each step downhill generates jarring impacts that squander energy and strain your joints. Descending on foot isn't always as straightforward as we might anticipate.

More than just a mode of transport.

So, the next time you glide past pedestrians with ease during your morning cycle commute, spare a moment to admire the biomechanical masterpiece beneath you. Your bicycle is more than just a means of transport; it's a finely tuned machine that collaborates with your physiology, converting your raw muscle strength into efficient movement.