When we walk, the quadriceps muscle and hamstring are active. The quadriceps muscle is the muscles that extend the knee and the hamstring is the muscles that bend the knee. The muscle weakness of these muscles causes falls and knee pain. Measuring instruments that measure these muscle strengths are used in clinical practice. However, since it does not take into consideration the position of muscle and bone attachment, it cannot be measured under conditions that maximize muscle strength. The purpose of this study is to develop a muscle strength measuring device of the quadriceps femoris and hamstring under conditions that maximize muscle strength taking into consideration the position of muscle and bone attachment. In this study, muscular strength was measured for 7 men in their 20s and 7 females in their 20s. As a result, we could measure muscular strength of the quadriceps femoris and hamstring under conditions that maximize muscle strength. However, the measurement results of subjects with long thigh tended to decrease. This result may be due to the lack of fixation of the knee if the subject is a long thigh. Therefore, to measure muscle strength accurately, it was suggested that it is necessary to design a measurement instrument that takes the subject's thigh length into account.
