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  • Roger Yao

The locking system for parallel bar

- Why the athlete slip off the parallel bar

Parallel bar failing at Internaitonal Univsity Games

There is a video spread on the internet and in my WECHAT group last night (2023-8-2) about an American athlete who slipped off the double bar support at the Chengdu International University Games.

As seen on the video, when the athlete's centre of gravity was on the right side of the bar, the other side loosened (but the athlete did not notice). When he continued his next movement and his weight was on the left side, which was not tightly locked, suddenly sank, causing the audience to burst into laughter. Fortunately, this accident did not cause any injury to the athlete and was a minor incident during the competition.

Some audience immediately gave a judgement saying that the parallel bar quality was too bad to support the athlete’s weight. However, the official announcement later on confirmed that it was the American team coach’s negligence to forget to tight the lock system on the left side of bar.

As a quality guy in fitness & sporting equipment for almost 20 years, I tried to figure out the mechanism of the lock system on parallel bars.

Due to the low-definition resolution video and the long shooting distance, we were unable to determine the brand of this double bar or see the structure of the locking mechanism. Anyway, that didn't stop us from doing some technical research and understand what kind of lock mechanism is more reliable, which could also reduce the likelihood of negligence that the American coach did in the video.

The types of parallel bar locking system

1)Fixed without adjustment

This fixed mechanism is used in non-professional sports settings and is commonly found in community outdoor sports facilities or gyms. Because the user cannot adjust the width or height, there is no problem with the adjustment locking failing.

2)Non-professional entry level spring loaded pin/knob mechanism

This type of design is usually used in home fitness products. When adjusting the height, the position is fixed by finding the selection holes through spring-loaded pins, and then tightening them through knobs to reduce side-to-side wobble.

Decathlon parallel bar locking system
locking system


3)Professional Grade Rotary Handle Type

This design is used in the "CLASSIC" series of double bars from the American company AAI. Parallel bars with this type of fixed locking mechanism are also frequently used in international events.

This design increases friction by having two knobs at a 90-degree angle apart against the riser. However, the final locking position of the rotating knobs is not consistent, and the user cannot detect whether the knobs are locked in place relatively easily by visual observation. If the user neglects to lock it in place, it may still slip out of place during exercise.

CLASSIC™ Parallel Bars
CLASSIC™ Parallel Bars

4) Professional Push Button Pull Handle Type

There are some companies in the world that use this type of structure for their double bar products, and one of the most famous brands is Spiet, a long-established German event equipment company.

Spiet,locking system for bars
Spiet parallel bars

This kind of mechanism is designed with two parts (button A and pull handle B). Button A is located below the height position and the locking handle B is located above.

Compared to the rotating handlebar type of fixing, this push-button handlebar mechanism is more reliable, easier to operate and more aesthetically pleasing. It is easy to detect if you forget to lock the pull handle.

The adjustment and locking method are as follows:

  • When adjusting the up-down position, firstly pull up the handle B.

  • Then push the button B

  • Adjust to desired position.

  • Finally, pull down the handle completely.

Please refer to assembly instruction for Spieth paraller bars below

So, which type of locking mechanism you prefer if you are a parallel bar player?

You are welcomed to contact me to discuss on this topic.


Roger Yao (

  • The founder of FITQS/FQC

  • The columnist of magzine <China Fitness Equipment>

  • 20 years in fitness/sporting equipment OEM/ODM technical and sourcing management.


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