[Purpose] Few studies have investigated diurnal and day-to-day changes in the thigh circumference of the residual limb in female amputees. In this study, we used a limb circumference measuring device to confirm the reliability of the measurement and compared the changes in the measured values over time. [Participants and Methods] The study measured and compared the femoral circumference in 2 female amputees and 8 healthy female non-amputees in the morning and evening. [Results] Reliability was assured by measuring the circumferential diameter in triplicate. There were no significant interactions in both diurnal and day-to-day variations, however, in both variations, there were significant differences in the femoral circumstance at any site among the non-amputees. [Conclusion] The amount of edema increased in the evening and varied from day to day in the non-amputees.

[Purpose] This study aimed to investigate how the speed alteration task, which gradually increases or conversely decreases walking speed, affected walking stability. [Participants and Methods] Thirteen healthy young adults performed two walking tasks as follows: the speed alteration task, in which the walking speed was gradually increased or decreased, and the speed constant task, in which the walking speed was maintained at a comfortable level. Before and after each task, the Timed Up and Go test was performed to analyze time, walking speed, and trajectory. The overall score of the Timed Up and Go test, as well as the scores of the three major segments (i.e., forward, turning around, and return), and nine subsegments, were calculated and analyzed. [Results] During the speed alteration task, parameters including time and walking speed of the Timed Up and Go test were significantly improved. Also, the same parameters increased significantly in the forward and return segments. These increases were also observed in the first subsegment of the forward segment and the second subsegment of the return segment. [Conclusion] The speed alteration task improved walking stability, so it could be used in gait training to improve walking stability.

[Purpose] This study investigated changes in the physical function of frail elderly females who participated in a long-term care prevention project for ≥1 year. [Participants and Methods] There were 125 females included. Measurement items were body mass index, 5-m maximum gait time, 5-m normal gait time, standing on one leg with eyes open, timed up and go test, and grip strength and measured every six months. [Results] Grip strength decreased significantly after six months and one year compared to that of the start. The other measurements had no significant differences at start, after six months, and after one year. [Conclusion] This study investigated changes in physical functions in the frail community-dwelling elderly females one year after starting in a long-term prevention care program. Consequently, after one year in the program, no change was noted in measurements, such as gait speed, but only grip strength decreased. Likely, the exercise program mainly targeted the lower limb muscles. Therefore, although functions mainly use the lower limbs, such as walking, may be maintained, those using the upper limbs may be affected by aging.

[Purpose] This study aimed to examine the difference in the excitability of the primary motor cortex between initiation-predictive and non-predictive tasks, where the onset of muscle relaxation is predicted and not predicted, respectively. [Participants and Methods] Seventeen participants were asked to perform rapid muscle relaxation either through an initiation-predictive or non-predictive task. The baseline was set at 20 percent of the maximum voluntary contraction. Motor-evoked potentials and H-reflexes elicited by transcranial magnetic stimulation and median nerve electrical stimulation, respectively, were measured. The mean stimulation time from the onset of relaxation was calculated, and the motor-evoked potentials and Hoffmann’s reflexes elicited during the first (immediately before relaxation) and second half (long before relaxation) were compared. [Results] The amplitude of the motor-evoked potential significantly increased in both initiation-predictive and non-predictive tasks when compared to the baseline, indicating increased excitability of the primary motor cortex. The motor-evoked potential from the initiation-non-predictive task, but not the initiation-predictive task, was associated with increased excitability of the primary motor cortex immediately before relaxation. [Conclusion] Variations in the predictability of motor movements are associated with changes in muscle relaxation control in the central nervous system.

[Purpose] This study aimed to identify the relationship between the early postoperative perceived leg length discrepancy after unilateral total hip arthroplasty and the progression of osteoarthritis in the contralateral hip. [Participants and Methods] This was a retrospective cohort study of 65 patients who underwent primary unilateral total hip arthroplasty for bilateral hip osteoarthritis. The minimum joint space width of the contralateral hip was measured preoperatively. The change in minimum joint space width one year postoperatively compared with preoperatively was measured. At three weeks postoperatively, patients were divided into the perceived and non-perceived leg length discrepancy groups using the block test. Patients with a perceived leg length discrepancy of 2 mm or more and less than 2 mm were grouped into the perceived and non-perceived leg length discrepancy groups, respectively. Before and after propensity score matching, the change in minimum joint space width between the two groups from the preoperative period to one year postoperatively was compared. [Results] In the pre-propensity matching sample, there was no significant difference in the change in minimum joint space width between the two groups. In the post-propensity matching sample, the change in minimum joint space width in the perceived leg length discrepancy group was significantly larger than that in the non-perceived leg length discrepancy group. [Conclusion] The early postoperative perceived leg length discrepancy after unilateral total hip arthroplasty may affect the progression of osteoarthritis in the contralateral hip.

[Purpose] Fall risk is immanent in humans because they are bipedal. Bipedalism has transited from quadrupedalism in both evolutional and developmental contexts. Past studies have measured the peak vertical ground force of forelimbs and hindlimbs in quadrupedalism; and revealed that load dominancy shifted from forelimbs to hindlimbs during evolution. The dominance of hindlimb peak vertical ground force allows forelimb freedom and is considered important for locomotor evolution toward bipedalism. With this consideration, we hypothesize that hindlimb peak vertical ground force is dominant in human adults when they designedly crawl in a quadrupedal manner. [Participants and Methods] Six healthy human adults crawled on their hands and knees over a pressure platform. We calculated the peak vertical ground force of their hands and knees by integrating the pressure of the contact area of each limb. [Results] The mean knee peak vertical ground force at 0.694 (per body weight) was significantly higher than that of the hand at 0.372 (per body weight). The mean hand/knee peak vertical ground force ratio was 0.536; therefore, it was −0.624 on the natural logarithmic scale. [Conclusions] Our findings on human adults are compatible with existing considerations on locomotor evolution toward bipedalism. Our findings contribute to the comprehensive understanding of human locomotion.

The authors would like to apologize for the mistake in PARTICIPANTS AND METHODS.

In line 27 of PARTICIPANTS AND METHODS (p 499) “0.2 mm” should have been “2 mm”.