Characteristics of the life habits of obese students at one of Japan's National Colleges of Technology.

Aim This study clarified the characteristics of life habits of obese Japanese male students at the National Colleges of Technology, Japan. Materials and methods Healthy students aged 15-19 years answered a questionnaire containing 21 items on the following five categories of life habits: general exercise, meals, sleeping, leisure activity and illness or injury history. The subjects were divided into three groups based on the criteria of body mass index (BMI) and body fat percentage (%BF): non-obese (%BF < 20%, n = 420), overweight obese (%BF ≥ 20% and BMI ≥ 25, n = 99), and hidden obese (%BF ≥ 20% and BMI < 25, n = 60). The mean differences in waking time, bedtime and amount of time spent walking, sleeping and watching TV per day were examined using one-way analysis of variance (ANOVA) and chi-square tests for each item. Results The overweight obese and hidden obese groups engaged in less exercise time, were more likely to eat until they were full at meals and were less likely to eat between meals or late at night than the non-obese group. In addition, the non-obese group had significantly later waking times and significantly less TV-watching time than the overweight obese group. There were no significant differences with respect to leisure activity and illness or injury history among the three groups. Many students in all groups had regular waking times and were not performing any leisure activities. Conclusion The findings suggest that obese students may need further guidance to help them maintain a healthy life and appropriate weight.

Effect of shoes with rounded soft soles in the anterior-posterior direction on the center of pressure during static standing.

Shoes with curved rocker bottom soles may induce an unstable standing posture. This study was aimed to mainly examine the effect of such shoes on the center of pressure (COP) during static standing. Ten healthy young male adults had their COP measured during static standing with four types of shoe conditions (Stretch Walker(®): SW (shoes with curved rocker bottom soles), Masai Barefoot Technology®: MBT (similar to SW in form and material), more conventionally soled shoes with a typical toe-spring: MCS, and bare feet: BF) for 60s. The mean path length and mean velocity of Y (front-back) axis were significantly greater when wearing the MBT than when wearing the SW, and when wearing the SW than when BF or when wearing the MCS. In addition, mean velocity of X (left-right) axis, area surrounding root mean square, root mean square, and root mean square of Y-axis were significantly greater when wearing the MBT than when wearing the SW, MCS, or when BF. In conclusion, when wearing the MBT or SW with rounded sole, static standing posture becomes unstable because of their characteristics as compared with wearing MCS or when BF, but the MBT has a larger sway in the front-back direction than the SW.

Examination of factors affecting gait properties in healthy older adults: focusing on knee extension strength, visual acuity, and knee joint pain.

BACKGROUND AND PURPOSE: Gait properties change with age because of a decrease in lower limb strength and visual acuity or knee joint disorders. Gait changes commonly result from these combined factors. This study aimed to examine the effects of knee extension strength, visual acuity, and knee joint pain on gait properties of for 181 healthy female older adults (age: 76.1 (5.7) years). METHODS: Walking speed, cadence, stance time, swing time, double support time, step length, step width, walking angle, and toe angle were selected as gait parameters. Knee extension strength was measured by isometric dynamometry; and decreased visual acuity and knee joint pain were evaluated by subjective judgment whether or not such factors created a hindrance during walking. RESULTS: Among older adults without vision problems and knee joint pain that affected walking, those with superior knee extension strength had significantly greater walking speed and step length than those with inferior knee extension strength (P < .05). Persons with visual acuity problems had higher cadence and shorter stance time. In addition, persons with pain in both knees showed slower walking speed and longer stance time and double support time. CONCLUSION: A decrease of knee extension strength and visual acuity and knee joint pain are factors affecting gait in the female older adults. Decreased knee extension strength and knee joint pain mainly affect respective distance and time parameters of the gait.

Postural stability during one-leg stance on an unstable moving platform and its relationship with each leg.

This study examined the laterality of the supporting leg in postural stability during a one-leg stance test on an unstable moving platform and its practice effect. 30 male university students were evaluated using the omnidirection stability index (OSI) during a one-leg stance test on an unstable moving platform (three trials). The leg used when kicking a ball was defined as the manipulation leg (ML) and the supporting leg was defined as the non-manipulation leg (NML). According to the two-way repeated measures analysis of variance (ANOVA; trials x legs), a statistically significant difference was observed only on the leg factor, and OSI values of the second and third trials were less for the ML than the NML. The correlation between both legs was statistically significant but not high. The ML was superior to NML with regard to stability, and no practice effect with trials was evident in either leg.

Sex and age-level differences of walking time in preschool children on an obstacle frame.

BACKGROUND: Stepping over an obstacle is a kind of compound movement that makes walking more difficult, especially for preschool children. This study examines sex and age-level differences in walking time in preschool children on an obstacle frame. METHODS: The participants included 324 healthy preschool children: four-year-old boys (51) and girls (51), five-year-old boys (50) and girls (60), and six-year-old boys (62) and girls (50). A 5 cm- or 10 cm-high obstacle (depth 11.5 cm, width 23.5 cm) was set at the halfway point of a 200 cm × 10 cm walking course. RESULTS: The participants walked to the end of the course and back as fast as possible under three conditions: no obstacle, low obstacle and high obstacle. Walking time showed age-level differences in all conditions, but there were no differences in sex. Age levels were divided into two groups, with one group within the first six months of their birthday, and the second group within the last six months of that year. Walking time for children in the first half of their fourth year was longer than that of the five- and six-year-old children. In addition, for children in the last half of their fourth year, walking time was longer than both sexes in the last half of their fifth and sixth years. The children in the latter half of their fifth year had a longer walking time in the high obstacle condition than those in the last half of their sixth year. In the four-year-old participants, walking time was shorter with no obstacles than with a high obstacle frame. CONCLUSIONS: In the above data, obstacle course walking time does not show a gender difference, except that the four-year-old participants needed longer than the five- and six-year-old children. Setting the obstacle 10 cm high also produced a different walking time in the five- and six-year-old participants. The high obstacle step test (10 cm) best evaluated the dynamic balance of preschool children.

The effects of shoes with a rounded soft sole in the anterior-posterior direction on leg joint angle and muscle activity.

This study examines the effect of these shoes on the leg joint angle and muscle activity during walking. Ten healthy young male adults (mean age: 24.1±4.3 years) walked on a walkway while wearing one of three kinds of shoes with a rounded soft sole in the anterior-posterior direction (Stretch Walker: SW, mass: 440 g), MBT (Masai Barefoot Technology; similar to the SW in form and material, mass: 600 g), and flat-bottomed shoes (FS, mass: 420 g)). After familiarizing themselves with the shoes, subjects walked twenty laps on the walkway, which was about 40 m long (mean speed: 4.1 km/h). After a sufficient rest, they repeated this with the other shoes. During walking, the volume of muscle discharge was measured once every 2 laps. The mean value of the 10 measurements was used as the evaluation variable for integral values and joint angle, while the right foot touched the ground twice. In conclusion, the range of leg movement during walking was smaller when wearing shoes with a rounded soft sole in the anterior-posterior direction (SW and MBT) than when wearing normal shoes (FS). However, the effects of the SW and MBT on leg muscle activity during walking differ little from wearing the normal shoes during a leisurely 10-min walk.

Gait characteristics when walking with rounded soft sole shoes.

This study aimed to examine the effect of shoes with a rounded soft sole (Stretch Walker: SW) on gait. Fifteen healthy male (mean age: 23.2) walked under three conditions (SW, Flat-bottomed Shoe: FS, Barefoot: BF). Including walking speed, stance time, step length were selected as temporal-spatial parameters. The angle of hip, knee, and ankle joints during particular phases were selected as kinematic parameters. Walking speed, stance time, step length and flexion angle of the ankle joint at initial contact were greater when wearing either shoe than walking BF; cadence was faster walking BF than wearing either shoe; double support time increased (FS>SW>BF); step width was greater (FS>SW>BF); walking angle was greater wearing the SW than wearing the FS and walking BF; and range of motion and maximum flexion angle of the hip and knee joints were greater wearing the FS than walking BF. In conclusion, wearing the SW with a heel-to-toe rocker and soft sole changes the double support time, step width, and walking angle and increases step length and walking speed compared to walking BF. The difference of the range of motion in hip and knee joints was larger between walking BF and wearing the FS than between walking BF and wearing the SW.

Comparison of the body-sway characteristics of young adults compared to healthy elderly and elderly with equilibrium disorder.

The study compared body-sway characteristics of 380 young adults, 342 generally healthy elderly without disequilibrium disorders, and a group of 33 elderly with disequilibrium disorders. Center of foot pressure (COP) was measured for 1 min. using an Anima's stabilometer G5500 with a data sampling frequency of 20 Hz. Four high reliability measures were used to evaluate body sway (unit time sway, front-back sway, and a left-right sway, and high frequency band power). Unit time sway, left-right sway, and high frequency band power were significantly larger for the group of elderly with disequilibrium disorders, and smaller for the healthy elderly people and young adults, in that order. Front-back sway was significantly larger in the elderly with disequilibrium disorders and healthy elderly than in young adults. The elderly with disequilibrium disorders had a larger and faster sway than young adults as well as the healthy elderly, particularly in the left-right direction. It appears aging was specifically associated with larger influence on the front-back sway.

Relationship among gait parameters while walking with varying loads.

This study aimed to clarify the relationships between loads and gait changes and among gait parameters while walking with various loads. Fifteen healthy young male adults (mean age: 22.1+/-1.6 years) walked with four kinds of loads based on each subject's body mass (0, 20, 40, and 60% of body mass: BM) on his back. Walking speed, cadence, stance time, swing time, double support time, step length, step width, walking angle, and toe angle were selected as gait parameters.Walking speed, cadence, stance time, and double support time changed significantly with loads. The walking speed showed significant correlations with the swing time at 0% BM (r=-0.64) and the walking angle at 60% BM (r=-0.52). Significant correlations were found between swing time and double support time at 0, 20, and 40% BM (r=0.53-0.63) and between walking speed and step length at 40 and 60% BM (r=-0.61, -0.67). In conclusion, walking with loads produces large gait changes. The relationship between swing time, double support time, and walking speed, as well as between walking angle, step length, and walking speed changes greatly with loads. These changes may occur in order to maintain a stable posture.

Relationships between ground reaction force parameters during a sit-to-stand movement and physical activity and falling risk of the elderly and a comparison of the movement characteristics between the young and the elderly.

This study aimed to examine the relationships between ground reaction force during a sit-to-stand (STS) movement and physical activity and falling risk of the elderly and the difference of the movement characteristics between the young and the elderly. Sixty elderly females who can achieve a STS movement by themselves and 30 healthy young females were measured for ground reaction force during STS movement from a chair, adjusted for lower leg length height. The elderly's physical activity and falling risk were also assessed. Physical activity and falling risk significantly correlated with parameters on force exertion during hip lift-off and knee-hip joint extension phases (|r|=0.26-0.41). Significant differences were found in ground reaction force parameters of all phases between the young and the elderly and STS movement of the elderly was suggested to result in poor force exertion and slowing down. The above tendency was noticeable in the hip lift-off and knee-hip joint extension phases. In conclusion, force exertion in hip lift-off and knee-hip joint extension phases of STS movement is related to physical activity and falling risk in the elderly. These phases may be useful to evaluate the elderly's physical activity and falling risk.

Age-stage differences in body sway during a static upright posture based on sway factors and relative accumulation of power frequency.

This study was done to examine age-stage (preschool children, young adults, and elderly people) differences in the center-of-pressure sway using body-sway factors (unit-time sway, front-back sway, left-right sway, and high frequency-band power), power-spectrum distribution, and relative accumulation of power frequency (25%, 50%, and 75% RAPF) of the center-of-pressure spectrum. The center-of-pressure movement for 1 min. was measured twice using Anima's stabilometer. Data-sampling frequency was set at 20 Hz. Significant age-stage differences were found for 3 factors except for left-right sway, which was larger for preschool children and elderly than for young adults. The power spectrum of body sway in any age-stage was noted mainly in low frequency bands. A marked age-stage difference was found at 75% RAPF. Body-sway characteristics in each age-stage differ, and differences of postural-sway frequency are marked in the low frequency bands.

Age and sex differences in various stepping movements of the elderly.

AIM: This study aimed to examine sex and age differences of various stepping movements in the elderly and to clarify useful stepping movements for evaluation of their dynamic balance. METHODS: Two hundred and eighty-six healthy elderly subjects who could walk independently (male mean age = 71.2 +/- 7.1 years; female mean age = 71.5 +/- 6.0) performed the following stepping tests: back and forth; up and down with a 5 cm tall step; and in-place stepping matching three tempos (44, 66 and 132 b.p.m.). Step number, single and double support times in the former two stepping tests, and time difference between metronome sound and grounding time in the latter tempo stepping tests were selected as evaluation parameters. RESULTS: An insignificant sex difference was found in all parameters. Hence, the data of men and women was pooled to examine age differences. Significant age differences were found in the step number and double support time of back and forth and up and down stepping tests and in the time difference of three tempo stepping tests. The step number in younger age groups and the support times in older age groups tended to be larger. CONCLUSION: No sex difference was found in evaluation parameters of all stepping tests, and all parameters tended to be superior in the younger elderly. The elderly experienced more difficulty matching slow tempos than fast tempos in the in-place stepping test. The back and forth, up and down and in-place matching tempo stepping tests may be useful for evaluating dynamic balance ability of the elderly.

Body-sway characteristics during a static upright posture in the elderly.

AIM: This study aimed to determine the reliability and sex and age-level differences of body-sway parameters, based on center of pressure (COP) measurements, during a static upright posture in the elderly and to clarify their body-sway characteristics in comparison with those of young adults. METHODS: The subjects were 50 healthy elderly and 50 healthy young adults. They had no evidence or known history of disorder. The data sampling frequency was 20 Hz. Thirty-six highly reliable parameters were selected from the following seven domains: distance; position; distribution of amplitude; area; velocity; power spectrum; and vector. In addition, four body-sway factors (unit time sway, front-back sway and a left-right sway and the high-frequency band power) were also measured. RESULTS: In the elderly, most body-sway parameters had very high reliability and did not show significant sex or age-level differences. The degree of body sway was greater in the elderly than in young adults, and marked differences were found, especially in sway velocity and periodicity. The four body-sway factors showed almost the same tendency as the 32 sway parameters. CONCLUSION: We judged that the body sway in the elderly showed large individual differences. Approximately 10% of the elderly subjects may be outside the standard range as compared to young adults, mainly in parameters relating to velocity and spectrum. Because the body-sway characteristics of the elderly are considerably different from those of young adults, we may need unique criteria to evaluate their body sway.

Simple and easy assessment of falling risk in the elderly by functional reach test using elastic stick.

Dynamic balance ability related to maintaining postural stability during movement is closely tied to fall risk in the elderly. The functional reach (FR) test has been developed to evaluate their dynamic balance. Although a simple and new FR test using an elastic stick has been proposed by modifying the above original FR test, the abilities related to both FR tests are judged to differ because of the large difference in the testing method. This study aimed to compare center of gravity fluctuation, muscle activity and functional reach distance as measured by the original FR test and the elastic stick FR test. First, reach distance, back/forth and right/left moving distance of the center of gravity, and activity of the lower leg muscles (soleus and tibialis anterior) were compared between both tests based on data obtained from 30 young male adults. All parameters except for the right/left moving distance were significantly larger in the elastic stick FR test. Next, the reach distance was examined in both FR tests using 53 elderly subjects; it was significantly longer in the elastic stick FR test, but showed no significant sex difference. The reach distance in both tests was significantly shorter (about 7 cm) in the elderly than in young adults. In conclusion, the elastic stick FR test involves greater leg muscle strength exertion and forward transferring of the center of gravity as compared with the original FR test. Because the elastic stick FR test relates largely to leg muscle function and equilibrium function, it may be more useful for evaluating the dynamic balance ability of the elderly.

Suprailiac or abdominal skinfold thickness measured with a skinfold caliper as a predictor of body density in Japanese adults.

Measurement of subcutaneous fat thickness with a skinfold caliper is a simple and inexpensive technique for assessment of body composition, but is influenced by the skin site or the obesity level. The resulting measurement errors may influence the prediction accuracy of body density. We therefore aimed to clarify the characteristics of measurement errors with a skinfold caliper and to determine useful measurement sites for the prediction of body density in Japanese adults of wide-ranging age and obesity levels. The present study included 126 Japanese male and 77 female subjects ranging from 21 to 81 years old. They were divided into a "non-obese group" and an "obese group", based on the Japanese criteria of obesity (BMI > or = 25 kg/m(2)). Subcutaneous fat thickness was measured at 14 sites with a skinfold caliper and ultrasound. Percent body fat was measured by dual-energy x-ray absorptiometry, and body density was calculated using Brozek's formula. Sex and obesity level differences in the measurement error of skinfolds (ultrasound minus skinfold caliper measurements) were examined by 2 x 2 ANOVA (sex and obesity groups) for each site. The relationship between body density and the systematic error was examined. We developed an accurate prediction equation for body density with smaller measurement and systematic errors. Although measurement errors in skinfold thickness tended to increase with increasing obesity levels, the influence was smaller for the abdominal and suprailiac skinfolds compared with other sites. Measurement of suprailiac or abdominal skinfold thickness is useful to accurately estimate body density in Japanese adults.

Comparison of quantitative analysis and fractal analysis of center of pressure based on muscle fatigue.

To examine the influence of muscle fatigue on center of pressure displacement during quiet standing using quantitative and fractal analyses, 12 healthy young men and women did the exercise stress test on the triceps surae muscle until fatigued. Subjects were measured for body stability for 60 sec. before and after the exercise. Quantitative analysis showed that center-of-pressure parameters for distance, velocity, amplitude distribution, and mean vector length of sway in the anterior/posterior direction changed significantly after muscle fatigue but not on the periodic parameters. This result suggested that quantitative analysis may identify the effects of muscle fatigue on the parameters that show displacement in the anterior/posterior direction of center of pressure. Fractal analysis indicated the value of critical point coordinates increased after muscle fatigue. This analysis can clarify the fundamental postural control strategy and time-series characteristics of postural sway which cannot be identified by spectral analysis.

Influence of the relative difference in chair seat height according to different lower thigh length on floor reaction force and lower-limb strength during sit-to-stand movement.

Chair-seat height affects the burden on the lower-limbs during sit-to-stand (STS) movement. Previous studies used the same height chair, attaching importance to practicability, but the difference in each subject's lower thigh length may relate to the burden on the lower-limbs. This study aimed to examine the influence of different lower thigh lengths on floor reaction force and lower-limb strength during an STS movement. Thirty young-adult male subjects participated in this study (age: 22.7+/-2.6 yr, height: 172.8+/-4.8 cm, body-mass: 66.3+/-5.2 kg). The subjects were divided into three groups (G1>42 cm, 42 cm > or =G2 > or =38 cm, 38 cm >G3) based on lower thigh length (G1: 44.1+/-2.5 cm, G2: 39.8+/-1.3 cm, G3: 34.3+/-2.1 cm). Namely, G1 was characterized by lower thigh length longer than 105% of 40 cm, G2 by 95-105% of lower thigh length and G3 by lower thigh length less than 95% of 40 cm, respectively. Subjects performed an STS movement twice from chairs at 40 cm-height and height adjusted by the lower thigh length of each subject. Vertical floor reaction force and electromyogram (EMG) on the rectus femoris and tibialis anterior muscles during an STS movement were measured to evaluate the force of knocking over and the burden on the lower-limbs. Fifteen parameters regarding floor reaction force (10) and EMG (5) were selected for analyses. Significant differences were found in floor reaction force at hip-syneresis (F1) and the impulse between hip-syneresis and appearance of the peak floor reaction force (F2). G1 was greater than G2 for the former, and G3 for the latter. Significant differences were found in active muscle mass of the tibialis anterior from the beginning of an STS movement to hip-syneresis (TE1) and peak active muscle level of the tibialis anterior (TE6). G1 was greater than G2 for the former, and G2 and G3 for the latter. It was suggested that when an STS movement is performed using a chair with the same height for each subject, the load imposed on the subject's leg at the time of an STS movement and the STS movement achievement strategy differed since chair seat height changes relatively by the difference in lower thigh length. Moreover, it is thought that the difference in these load conditions and movement strategies occurs when the chair seat height of a subject's lower thigh length is longer than 110%. When conducting the ability to achieve STS movement rating test, chair seat height considering each subject's lower thigh length may be needed.