Patellar movement perception related to a backward-leaning standing position.

[Purpose] To investigate the patellar movement perception related to backward-leaning standing. [Subjects and Methods] Both the patellar range of motion during backward-leaning standing and perception related to patellar movement were analyzed using television-x irradiation images in 12 randomly selected healthy young individuals. [Results] Starting in a relaxed condition, two types of patellar movements were confirmed: those where the patella moves (patellar movement trials) and those where the patella does not move (patellar non-movement trials) during backward-leaning standing. The rate of the perceived patellar motion in the patellar movement trials was significantly higher (90.9%) than that in the patellar non-movement trials (66.7%). When starting in a quadriceps-contracted condition, the rate of perceived trials (77.0%) was significantly lower than that of the trials started in a relaxed condition. [Conclusion] The perception of patellar movement while backward-leaning standing may contribute to the perception of a backward standing position especially when the patella really moves.