A bicycle, commonly a two-wheeled terrestrial vehicle operated by pedaling, serves as an eco-friendly means of transportation. Derived from "bi," meaning two, and "cycle," referring to wheels, it signifies a two-wheeled vehicle.

It serves as an eco-friendly mode of transport for commuting and travel and is increasingly embraced by many as a fitness tool for cycling exercises and recreational trips. Moreover, it's a competitive sport, including road cycling, mountain biking, track cycling, and stunt biking.

With over a century of history, bicycles have revived as favored modes of transportation and fitness tools worldwide, especially in developed nations. The focus in the bicycle industry is shifting from traditional commuting to sports, mountain, and leisure models. Globally, the demand for bicycles remains substantial, with an estimated annual trading volume of approximately USD 5 billion, according to data from Japan's CYCLEPRESS.

Bicycles are among humanity's most successful human-powered machines, comprising various simple mechanical elements to form a complex mechanism.

For beginners in cycling, choosing the right bicycle is essential. Bicycles can be broadly categorized as mountain bikes, road bikes, touring bikes, and folding bikes, each with its characteristics catering to different needs:

1. Mountain bikes offer excellent terrain adaptability with robust treaded tires, shock-absorbing systems, and cargo racks for long-distance travel, albeit at slower speeds.

2. Road bikes provide high speed, lightweight build, and aggressive seating, yet may be uncomfortable for beginners, with tires prone to slipping on gravel and narrow tires risking getting caught in drainage covers during urban commuting.

3. Folding bikes, although convenient for compact storage and combined metro and bike travel, might lack cost-efficiency compared to alternatives in the same price range.

4. Hybrid bikes combine features of road and mountain bikes, featuring slightly thicker wheels than road bikes, providing a comfortable riding posture ideal for riding on gravel roads.

Cycling offers various advantages:

1. Improves Mental Health: Active individuals exhibit 32% higher health levels than inactive ones, with exercise releasing hormones like adrenaline and endorphins, boosting confidence through achieving new goals.

2. Aids Weight Loss: Cycling burns calories at rates ranging from 400 to 1000 per hour based on intensity and rider weight, aiding in weight management.

3. Strengthens Muscles: Cycling not only burns fat but also strengthens muscles around the hips, thighs, quadriceps, and calves.

4. Enhances Lung Health: Recent studies show cyclists face less exposure to dangerous pollutants compared to motorists, pedestrians, and bus users, indicating better lung health among cyclists.

As a mode of transport, fitness tool, and competitive sport, the bicycle represents not just eco-friendliness and health but also a testament to human ingenuity in mechanical engineering. Its traditional value finds new vigor in modern times, catering to diverse needs in various forms.

From green sustainability to fitness and urban commuting, the bicycle, with its simple yet elegant design, intricately links people to nature and cities to well-being, becoming an indispensable part of lives worldwide. Cycling isn't just an action; it's a way of life, embodying ideals of health, vitality, and environmental consciousness.