BEIJING, April 19 (Xinhua) -- As the starter pistols sounded on Saturday morning, history was made. On the outskirts of Beijing, servos hummed and joints whirred as 20 bipedal robots bolted from the starting line, kicking off the world's first humanoid robot half marathon.

For the very first time, humanoid machines stepped onto a long-distance race track to compete alongside human runners, blurring the line between athletics and invention, and heralding a new era of robotic intelligence.

Over the past few months, Chinese startup teams have been dominating the global robotics stage with inventions that can perform impressive stunts like dances, backflips and Tai Chi. Powered by recent exponential leaps in AI, these machines have moved on from mechanical motions to remarkably lifelike movements.

Their designers believe that now is the perfect moment to showcase China's growing prowess in robotics manufacturing in a more eye-catching way.

Saturday's long-distance race put the durability and stamina of these Chinese inventions to the test, though battery replacements akin to pit stops in the F1 Grand Prix were permitted. Robots navigated diverse terrains, including smooth asphalt, cracked roads, puddles, and both gentle and steep slopes.

Prior to the highly anticipated race, the robot runners were surrounded by three to four mechanical and software engineers. The air crackled with tension as the final adjustments were made to various mechanicians, with intensive debugging processes continuing right up to the last possible moment.

Unease lingered among the human competitors, who were uncertain whether the robots would be able to complete the 21-kilometer race -- and if they could, whether they would win. Most had been rushed directly from their development labs to the race track, never having completed a full test run.

"We lightened the robot without compromising its strength, refined its leg design, and improved its thermal conductivity and air-cooling systems to boost stability and endurance," said Guo Yijie, a technician for the Tien Kung Ultra robot, explaining how his team had adapted the machine for the race.

Dressed in an orange vest, Tien Kung, which had the fastest time in the 5-kilometer qualifying race, started first and led the group.

Known for its resilience and constantly evolving athletic capabilities, the 1.8-meter-tall robot had previously set a record by climbing more than 100 consecutive outdoor steps.

Despite thorough preparations, however, Tien Kung encountered a minor setback when its lower leg component fractured during a pre-race field test, adding even more suspense to the competition.

In a surprising twist within just 100 meters of the starting line, a robot wearing a lifelike female face mask buckled at the knees and crashed to the ground. It was quickly overtaken by a 75-centimeter-tall robot in a shiny silver suit that had started later.

Another robot runner, known as Xuanyuan and famed for its diagnostic and emotional recognition AI capabilities, also stumbled shortly after it set off. Luckily, it regained its footing and continued on, albeit at a more cautious pace.

"When falling, humans can get back up with a few simple movements, but robots require multiple joints to work together, each with high torque requirements," said Yang Guodong, co-founder of a startup that designed CASBOT SE, another robot competitor.

The early kilometers of the race revealed the likely outcome: Tien Kung was the obvious robot frontrunner, though its speed was no match for humans. Strictly speaking, the robots' movements are more like speed-walking, as they cannot quite manage to get both feet off the ground.

The real drama unfolded at the 16-kilometer mark, where Tien Kung experienced a heart-stopping accident -- a sudden, jarring collapse. Its accompanying engineers scrambled, even rolling out a backup machine. A machine swap would have incurred an at least 10-minute penalty, according to the rules of the race.

Five minutes later, Tien Kung surged back to life and resumed running, its steady rhythm undisturbed and its metal frame catching the sun's glare as the clouds parted. Ahead of the procession was an olive-green Xiaomi SU7, an electric pace car that guided the machine runners.

For the first few kilometers, Noetix's N2 kept close pace with Tien Kung. At just 1.2 meters tall, it has short, broad legs that move with a firm and powerful stride. Its body swings back and forth with ease, giving it a running posture that is more human-like than Tien Kung's.

But N2 gradually fell behind, owing to multiple battery swaps and repairs that required engineers to perform frantic hard resets.

Many of the competing robots weren't brought to the race to chase medals. They stole the show in their own way, with one humanoid robot showcasing long legs resembling those of a praying mantis, and another wearing a comical black fishing hat.

The footwear on display during the race also told a story. Some robots were equipped with professional running shoes for shock absorption, while one clomped forward in rain boots for better traction, as it had rained the day prior.

It didn't take Booster T1 -- another robot racer -- long to show off its lively dance skills to onlookers. And a robot resembling a Transformer was quick to slide toward the right-hand railings as soon as the race began, as if attempting to escape.

Though still impressive to the casual viewer, these amusing moments highlighted that humanoid robotics are still in their infancy. For many robotics startups, the half marathon was both a platform to showcase their inventions and a real-world testing ground.

The defining moment of the race came 2 hours and 40 minutes in, when Tien Kung stormed triumphantly across the finish line.

While most human runners had long since completed the race, an eager group of robotics enthusiasts had modulated their pace to form a synchronized procession behind the robot champion. Tien Kung's average pace came in at approximately 8 kilometers per hour -- a milestone achievement in humanoid-robot running history.

"This performance was pretty much in line with our expectations," said Xiong Youjun, general manager of the Beijing Humanoid Robot Innovation Center, Tien Kung's developer.

N2 secured second place among the robots competing, and a machine designed by Shanghai-based firm DroidUp came in third. In total, six humanoid robots completed the race.

"Just being here and participating in this race feels like a victory. Finishing the race should be considered a greater triumph than winning," Xiong said. "This is the first step toward integrating robots into our daily lives. It's a historic moment."

The half marathon trail included a charming avenue lined with princess trees on both sides, leading to Beijing E-Town -- a hub of Chinese innovation, where cutting-edge firms in the robotics, semiconductor, biotech and commercial spaceflight sectors are driving the country's growth.

"Humanoid robots consist of thousands of parts, fueling a lengthy industrial chain," said Liang Liang, an official of the Beijing Economic-Technological Development Area (BDA), where Beijing E-Town is located. "China's robust and diverse manufacturing sectors provide a strong foundation for robot innovation."

Not all of China's leading robotics firms took part in Saturday's half marathon. UBTECH, headquartered in Beijing E-Town, focuses on deploying robots in factories to complete practical tasks, and its products are already training in auto factories.

Likewise, Kepler K2 robots from Shanghai, with a dual-arm payload capacity of 30 kilograms, look set to secure careers as logistics workers.

Currently in China, 470 industrial robots are deployed for every 10,000 manufacturing workers. And in the coming years, humanoid robots are poised to join human workforces, particularly in the handling of open-ended tasks requiring cognitive capabilities.

"The true purpose of this humanoid robot race is aligned with the eternal marathon of human aspiration," said Li Quan, another official of the BDA, which co-organized the event.

This August, a humanoid robot games is scheduled to be held in Beijing.

"Every physical course will end, but our journey toward human-robot collaboration has no finish tape," Li said.