On August 1, 2023, during the gymnastics qualification round of the Chengdu Universiade, the parallel bars suddenly sank, almost causing harm to the American athletes competing. Is there a problem with the equipment?

The competition department immediately retrieved the on-site video and submitted it to the technical chairman of this gymnastics event and the male technical representative for inspection. After their review, it was confirmed that the coach had failed to lock one end of the parallel bars after adjusting their distance, leading to the situation.

In line with the spirit of quality control practitioners in the fitness equipment industry, the author repeatedly watched multiple videos online and consulted relevant materials.

From the video, it can be seen that when the athlete’s center of gravity is on the jumping side (right side) after takeoff, the upright tube on the other side becomes loose (but the athlete does not notice). When he continues with the next movement and his center of gravity falls on the left side, the upright tube that was not locked suddenly sinks, causing a burst of laughter from the audience. Fortunately, this accident did not cause any harm to the athlete and can be considered a small episode in the competition.

Due to reasons such as video clarity and shooting distance, we cannot determine the brand of this parallel bars product or clearly see its locking device structure. However, this does not prevent us from conducting some research on its mechanical structure.

So, today we will talk about the locking method on the parallel bars.

Generally speaking, there are four types of parallel bars products:

1. Non-professional fixed parallel bars

This fixed mechanism is used in non-professional sports occasions, commonly seen in community outdoor sports facilities or gyms. Because users cannot adjust the width and height, there is no issue of adjustment lock failure.

2. Non-professional entry-level spring latch/knob mechanism parallel bars

This type of design is usually used in home economy fitness products. When adjusting the height, first find the selected hole to fix the upper and lower positions with a spring pin, and then tighten the knob to reduce lateral sway.

3. Professional Rotating Handle Parallel Bars

The design uses two knobs at 90-degree angles to support the uprights, increasing friction. However, the final locked position of the rotating handle is not consistent, making it difficult for users to easily determine if the handle is securely locked by visual observation. If a coach neglects to lock it properly, it may still slip during use.

This design is used on the “CLASSIC” series parallel bars products from the American company AAI. Parallel bar supports with this type of fixed locking mechanism are also commonly seen in some international competitions.

4. Professional Rotating Handle Parallel Bars

This type of product design has two parts (button A and pull handle B). The button A for selecting height position is located at the bottom, while locking the pull handle B is located at the top.

Compared to rotating handle fixed methods, this button handle mechanism is more reliable, easier to operate, and more aesthetically pleasing. If you forget to lock the pull handle, it is easily noticeable.

Many companies around the world use this structure for their double bar products, with the most representative being the German veteran sports equipment company Spiet’s double bar bracket product.