Reliability and Sex Differences in a Coordination Test of a Tracking moving target with the Center of Foot Pressure

Upper limb movements such as using chopsticks and writing require coordination. Hence, coordination tests such as the Purdue Pegboard test (Buddenberg & Davis, 2000) and the Moving Beans with Tweezers test (Shigematsu et al., 2001) have been developed (Ferslew et al., 1982; Noguchi et al., 2006; Nakafuji & Tsuji, 2001). Nagasawa et al. (2002) developed a controlled force exertion (CFE) test pursuing the changing demand values, appearing as sinusoidal and quasi-random waveforms on a personal computer, by grip strength exertion. These tests evaluate mainly upper limb coordination. However, since daily life and sports activities are generally performed standing upright, they require the coordination of the whole body. Visual, somatosensory, and sensory motor system functions contribute to efficiently perform movements. Moreover, in movements involving the whole body, many skeletal muscles are needed to maintain posture balance. However, not many tests have been developed that rationally evaluate coordination of the whole body. Recently, it has become possible to record the center of foot pressure (COP), which is projected at the body center of gravity on the plantar surface. As a result of the central nervous system (CNS) receiving feedback from visual, vestibular, and somatic sensations, the COP during standing always sways slightly. The total length and area of body sway have been widely used an index of balance function disorder and static balance ability. According to previous studies on COP sway (Ekdahi et al., 1982; Goldie, 1989; Hattori et al., 1992; Dickstein et al., 1993; Yamaji et al., 2001), the reliability of the COP parameters during standing is high. Recently, a balance measurement devive has been developed that can follow a randomly moving target by voluntary changes in COP. It is assumed that well-performing individuals who can coordinate their entire body can also meet their COP to a moving target on the above device. In short, this device can evaluate the coordination of the whole body. Yoshida et al. (1997) developed the test that tracks a moving target by COP. However, in their test the target moves linearly (back and forth, left and right) and constantly, the subjects can predict the target’s movements. A test involving an unpredictably moving target will be able to more accurately evaluate the coordination of the whole body.