Fig. 1

Testing and training position for hip exercises and quadriceps strengthening. A Hip muscle training and measurement were completed in the sitting position with the self-developed hip muscle testing and training device tied at 2 cm proximal to the knee joint. Participants performed isometric hip strength training by accomplishing hip abduction and adduction movements. The maximum hip adduction MVIC was displayed on the device screen when participants were squeezing the device by their legs on the inside. Similarly, the maximum hip abduction MVIC was displayed on the device screen when participants were pulling the device by their legs on the outside. B Participants completed quadriceps strengthening by taking the sitting position. During exercises, the testing device was fixed above the ankle joint. The maximum knee extensor strength was displayed on the device screen when participants extended their legs forward. The maximum knee flexor strength was displayed on the device screen when participants squeezed the machine backward