Science of Cycling: Human Power | Exploratorium (2024)

The Exploratorium is more than a museum. Explore our online resources for learning at home.

Science of Cycling: Human Power | Exploratorium (1)

Human Power Page: 1 of 2

The bicycle is a tremendously efficient means of transportation.In fact cycling is more efficient than any other method of travel--includingwalking! The one billion bicycles in the world are a testament to its effectiveness.The engine for this efficient mode of transport is the human body. Becausebodies are fueled by food, diet plays an important role in how the bodyperforms. Different muscle groups and types provide the power. Genetic inheritance,intensive training, and a competitive drive help top athletes push the boundariesof endurance and speed on the bicycle. How Far Do You Want To Go?

It takes less energy to bicycle one mile than it takesto walk a mile. In fact, a bicycle can be up to 5 times more efficient thanwalking. If we compare the amount of calories burned in bicycling to thenumber of calories an automobile burns, the difference is astounding. Onehundred calories can power a cyclist for three miles, but it would onlypower a car 280 feet (85 meters)!

Science of Cycling: Human Power | Exploratorium (3)

A comparison of the energy cost of various forms of transportation showsthat the bicycle is most energy-efficient.

Science of Cycling: Human Power | Exploratorium (4)

Bicycle is "a band that rolls across thecountry on bicycles and rocks in towns and cities along the way."

Bicycle has been touring the for the last few years. Using special lightweightguitars and a pared-down drum kit, the band hauls their own equipment inbike trailers. On one tour the band covered 200 miles (321 km) in 2 days.

"Heavy metal folk rap" is how the New York Times coinedthe band's sound. You can hear for yourself by clicking on the RealAudioSound below. You can also visit the band's Web page (available in the "References"section at the bottom of this page) for more information.

ColorFreak3:13 Minutes RealAudio

(Depending on your connection, theclip will be either mono or stereo)

Bike Culture

In the United States many people still consider cyclingonly a recreation or professional sport. But millions of Americans havefound that cycling is a great way to get work or get around town. Some cyclistsare banding together and forming organizations and events advocating issuesimportant to cyclists.

The bicycle has had a great impact on popular culture aswell. In fashion, the bicycle was largely responsible for changing women'sclothing in the late 1800s. Restrictive corsets and long dresses made wayfor bloomers and later trousers.

In the art world, the bicycle has made its way into paintingand sculpture. Most notably in Marcel Duchamp's Roue de Bicyclette or Bicycle Wheel which is considered the first 'readymade' sculpture.

Science of Cycling: Human Power | Exploratorium (5)

Duchamp's Roue de Bicyclette , the 1951 version. The original, createdin 1913, has been lost.

Fuel for Thought

Unlike automobiles, which require fossil fuel, cyclistsare fueled by food, a renewable energy resource. The type of food a cyclisteats can affect perfomance. All of us require water, protein, carbohydrates,fats, vitamins, and minerals to stay healthy. For top atheletes, maintaininga proper balance of these nuturients is extrememly important. U.S. Women'scross-country champion Ruthie Matthes explained, "Off the bike I tendto eat a lot of vegetables and fruits, high carbohydrates--but not to theextreme of where I'm eating just rice and potatoes. I do mix protein in."During races many cyclists will use high-carbohydrate drinks, bars, or evengels for instant energy.

Ruthie Matthes

Fluids

The human body is made up of mostly water, so even losingas little as 2 percent of the body's fluid through sweat can adversly affectcycling performance. Athletes riding in hot conditions for extended periodsneed to be careful. Severe dehydration can cause heat exhaustion or heatstroke and in even in some extreme cases, death. Cyclists are instructedto drink a few cups of water before riding and then to drink often duringexercise.

How Do Your Muscles Work?

A cyclist's legs provide the power for cycling. Muscleattached to the thighbone (femur) and the shinbone (tibia) do the majorityof the work. Your thighbone works like a lever and if it's longer than yourshinbone it will provide extra leverage on each stroke of the pedals. Thelength of your thighbone is determined by genetics, so if you have shortthighbones you can blame your parents. The length of the thighbone is notthe whole story, though--it takes muscles to move those bones.

Human Power Page: 1 of 2
Select "Forward" below to continue