Objective
Compared to elderly men, elderly women have substantially reduced performance of postural balance and greater risk of falls. To investigate the effect of age and sex on electromyographic (EMG) reaction time of tibialis anterior muscle contraction. Method Fifty-nine elderly subjects and 29 young subjects participated in this study. Subjects were instructed to dorsiflex the ankle of the dominant leg as forcefully and quickly as possible in response to audible beeps. EMG activity was recorded over the tibialis anterior muscle and delays in initiation and termination of EMG signal were measured by two examiners. Mean and intrasubject variability of each delay were used as outcome measures. Results Both the intra-examiner and inter-examiner reliability of delay variables were above 0.97. Delays in initiation and termination of muscle contraction, as well as their intrasubject variability, were significantly greater in the elderly (p＜0.01). However, there were no sex differences or interaction in all outcome measures. Conclusion These results demonstrate that the EMG reaction time and their variability increase in the elderly population with no sex difference.

Objective
To investigate gender differences in pain patterns and psychological variables among patients with chronic musculoskeletal pain. Method: Thirty-five male and thirty-eight female patients who visited our outpatient clinic due to chronic musculoskeletal pain were evaluated using a questionnaire survey. Chronic musculoskeletal pain was defined as pain lasting longer than 6 months. Patients were evaluated with visual analogue scale (VAS), pain site, pain duration and frequency. Beck depression inventory, state-trait anxiety index, somatization scale of symptom checklist-revised, symptom interpretation questionnaire, and pain catastrophizing scale were checked for psychological variables. Correlations among each variable were evaluated statistically. Results: Female patients with chronic musculoskeletal pain recorded higher scores on number of pain site, pain catastrophizing scale, rumination, magnification and catastrophic attribution than male patients (p＜0.05). In female patients, VAS was correlated significantly with depression, static anxiety, somatization, catastrophizing thought. rumination, magnification, helpless, and catastrophic attribution. Pain frequency was correlated significantly with somatization, catastrophizing thought, rumination, and helpless. Number of pain site was correlated with somatization, catastrophizing thought, magnification, and helpless. The correlation between pain patterns and psychological variables was also observed in male patients, but statistically less significant than female patients. Conclusion: We found gender difference associated with pain patterns and psychological variables in chronic musculoskeletal pain patients. Consideration of psychological factors may be important for management in female patients with chronic musculoskeletal pain. (J Korean Acad Rehab Med 2010; 34: 197-203)

Objective
To investigate the physical function of Korean elderly by age and gender and to assess the impact of declined physical function on their quality of life. Method: The Korean Longitudinal Study on Health and Aging (KLoSHA) is designed as a populationbased prospective cohort study on health and aging of Korean elderly aged 65 years and over. In one city among the central metropolitan area for one year, 1,000 subjects includeing a simple random sample and an oldest-old subpopulation participated in baseline study. All subjects are older than 65 years (76.3±14.8, 65∼98 years). We surveyed their general characteristics and symptoms related physical function and examined physical function, functional disabilities, balance function and quality of life with standardized assessment tools. Results: The strengths of quadriceps were preserved over the functional level, but BMI was significantly reduced according to age irrespective of sex. Physical function and quality of life were consistently decreased according to age in female elderly, especially over 80 years. On the contrary, male elderly under 85 years preserved their physical function. In 85∼89 year group, they showed the remarkable disabilities related to musculoskeletal conditions or pain and decrease of balance. Elderly people had greater disabilities and lesser confidence for balance, lower quality of life irrespective of sex. Conclusion:Significant gender differences in Korean elderly were found in the patterns of functional decline. Physical dysfunctions and disabilities are main factors lowering quality of life. (J Korean Acad Rehab Med 2007; 31: 457-465)

Objective
To analyze gender differences in adult foot shape with 3D foot scanner Method: Subjects included 1,107 feet of 872 healthy volunteers (male: 325, female: 547) without foot deformity. Total 23 foot parameters (foot length, inside joint length, outside joint length, ball girth, ball width, grading point length, vamp height, vamp length, waist girth point length, waist point length, waist height, waist girth, instep girth point length, instep point length, instep height, instep girth, short heel girth, long heel girth, throat opening, vamp waist angle, waist instep angle, instep-vamp height ratio, instep- ball girth ratio) were measured with 3D foot scanner. Uni-variate t-test was used to assess significant differences between men and women for each foot parameter, standardized to stature and foot length. Results: For a given stature, 20 of 23 foot parameters were greater in men than women (p＜0.05). For a given foot length, 13 of 23 foot parameters were greater in men than women (p＜0.05). Conclusion: This study demonstrated that female feet were different from male feet in a number of shape characteristics. These differences should be taken into account in the manufacture of women's shoes. (J Korean Acad Rehab Med 2006; 30: 626-631)