The association between genu recurvatum angle and the strength of the hip and knee muscles in standing workers

Background: Increased genu recurvatum (GR) angle is a risk factor for knee injury. Identification of factors causing GR is important for the prevention and rehabilitation of GR. Few studies have investigated the association between muscle strength and GR.

Objective: To examine the association between GR angle and hip and knee muscle strength in standing workersMETHODS:The participants in this study were 110 healthy volunteers (59 male, 51 female) who performed standing work in a theme park. The GR angle, muscle strength, and strength ratio of the lower extremities were measured to determine their associations with GR. The GR angle was measured using a Smart KEMA motion sensor, and muscle strength was assessed using a Smart KEMA strength sensor. Stepwise multiple regression models were used to investigate which muscles contributed most to the extent of the GR angle.

Results: Stepwise multiple regression analysis showed that the decreased hip external rotator to hip internal rotator ratio, increased knee extensor to knee flexor ratio, and young age were associated with an increased GR angle.

Conclusions: Many factors are known to increase the GR angle. However, this study investigated the roles of only hip and knee muscle strength. The results suggest that muscle strength ratios are more important than the weakness of any muscle.