The purpose of this study was to investigate the identification of distinct characteristics of postural control during transition from a dynamic into a static state in young and older adults. We tested 8 healthy elderly (mean age of 67 yr±0.8) and 8 healthy young (mean age of 23 yr±1.2) adult subjects. After the consent session, all trial participants gave written informed consent if they agreed voluntarily to participate. The subject transitioned from a dynamic state into a static state on the force platform during a step maximally. Center of pressure (COP) from the force platform were recorded during 15s from both feet on the force plat with a sampling frequency of 100 Hz. The anterior-posterior (A-P) and medial-lateral (M-L) direction mean of COP of older adult subjects produced different postural sway and presented significant difference on the distributed value of COP in the quiet standing after the dynamic task, in comparison to the young adult subjects. A-P direction and M-L direction mean of COP was significant difference during the seconds from 0 to 2 (p＜0.05), and 1.5 to 2.5 (p＜0.05), respectively, between young and old subjects. The difference in the mean distance of COP and distributed value of COP between younger and older subjects were revealed by this study. These findings indicate that the development of a simple, non-stressful technique to analyze postural control in older adults is highly useful.
There have so far been no studies examining the physical fitness and physical activity (PA), measured using objective measures, in homebound elderly people. The purpose of this study was to examine physical fitness levels and PA patterns and evaluate their relationships in homebound elderly people. In 2004, a total of 3964 community-dwelling elderly aged 65 years and over participated in a base line survey. The subject data were directly collected by in-home interviewer. Subjects were defined as being homebound if they went outdoors less than once a week. However, the subjects who could not go out without assistance due to sickness and/or disability were excluded from the analysis. In 2005, 38 homebound (22 men, 16 women) and 70 non-homebound (33 men, 37 women) older adults who participated in the base line survey were selected. Measurements of physical fitness levels and PA patterns measured using an accelerometer, were taken in 2005. The total steps per day did not significantly differ between homebound and non-homebound men and women. The time spent in 1.8 METs activity (corresponding to activity level 1 of the accelerometer) was significantly higher in women than in men for non-homebound and homebound, respectively. The time spent in lower-, moderate-, and high-intensity PA did not significantly differ between homebound and non-homebound men and women, respectively. Handgrip strength, knee extensor strength, leg extensor power, stepping and maximum walking speed were significantly higher in non-homebound than in homebound men and women. These results suggest that the physical fitness levels of homebound were lower than those of non-homebound, but no difference was observed in the PA levels between homebound and non-homebound.
The purpose of the present investigation was to examine the relationship between the open water swimming (OW) performance and the swimming speed at 2, 3, and 4 mmol/l of blood lactate concentration (SSLA2, SSLA3, and SSLA4) or the critical swimming speed (CSS). Six male collegiate swimmers performed the 10 kilometers of OW, as well as the multi-stage graded swimming test, in order to determine the SSLA2, SSLA3, SSLA4. Furthermore, the CSS was calculated based on the personal best records for 50 to 1500 meters of free-style indoor swimming. As a result, the SSLA2, SSLA3, SSLA4, and CSS corresponded to 102±6%, 106±6%, 110±7%, and 106±5% of the average swimming speed of the OW, respectively. Thereafter, the SSLA2 did not differ significantly in comparison to the average swimming speed of the OW, whereas the SSLA3, SSLA4, and CSS differed significantly with the average swimming speed of the OW (p＜0.05). Furthermore, the average swimming speed during the OW significantly correlated with the SSLA2, SSLA3, SSLA4, and CSS, respectively (p＜0.05). These results suggest that the OW performance significantly correlated with the swimming speed at 2 to 3 mmol/l of the blood lactate concentrations and CSS. Furthermore, regarding these parameters, the SSLA2 may accurately reflect the average swimming speed of OW.
The purpose of the present investigation was to examine the usefulness of the stepping rate for assessing the time spent in moderate to vigorous intensity physical activity (MVPA). In the present investigation, 11 young men wore two pedometers (LIFECORDER EX ; KZ, Walking Style ; WS) during controlled walking and jogging, as well as during free-living conditions for 3 days. In addition to the number of steps, the KZ determined the time spent in physical activity based on the intensity of the physical activity (light intensity physical activity (LPA); below 3 METs, and MVPA ; above 3 METs), and the stepping rate (≧60, ≧80, or ≧100 steps·min-1). In contrast, the WS was defined as the physical activity for a stepping rate of 60 steps·min-1 or more, continuously for longer than 10 min as the time spent in physical activity. Regarding the results, under continuous walking/jogging, the KZ-assessed LPA and MVPA well reflected the intensity of the physical activity. On the other hand, the WS accumulated the time spent in physical activity for longer than 90% of the actual exercise duration, regardless of the walking speed. Furthermore, the stepping rate corresponding to 3 METs was 102 steps·min-1. Under free-living conditions, however, the KZ-detected MVPA differed significantly in comparison to the time of the physical activity as determined by the other algorithms, except for the time spent in a stepping rate of 80 or higher steps·min-1. In conclusion, these results indicate that 100 steps·min-1 is a useful stepping rate for the assessment of MVPA. However, under free living conditions, the stepping rate should be determined at a higher frequency than a one minute interval length in order to improve the accuracy of the MVPA assessment.
Purpose：The purpose of this study was to investigate the effects of change in daily physical activity during an exercise intervention on health status and physical fitness. Methods：Participants were 22 obese middle-aged men (BMI : 29.1±2.8 kg/m2, 54.1±11.4 yr). They performed 90-min exercise sessions on a regular basis 3 days per week for 3 months. Physical activity (total energy expenditure, TEE ; activity energy expenditure, AEE ; and step counts) was measured using an accelerometer. Daily physical activity was defined as that which was performed outside of the exercise class. A 3-day food record was used to estimate energy intake. Results：Body weight decreased (-3.0±2.5 kg, P＜0.05). Vital age (VA), an index of comprehensive health status, and physical fitness age (PFA), an index of comprehensive physical fitness, significantly improved (VA : -8.7±5.5 yr, PFA : -8.5±5.1 yr, P＜0.05). Energy intake remained unchanged during the intervention (＋63.7±546.1 kcal/d). Daily physical activity increased (TEE : ＋83.0±130.1 kcal/d, AEE : ＋76.9±103.3 kcal/d, step counts : ＋1789±2819 steps/d, P＜0.05). Change in daily physical activity was correlated with change in VA (AEE : r＝-0.52, step counts : r＝-0.46, P＜0.05), while change in daily physical activity did not correlate with change in PFA. Conclusion：These results suggest that changes in daily physical activity during an exercise intervention are associated with improved health status.
To determine the effect of taurine on blood glucose concentration during prolonged exercise, fifteen male university students cycled for 120 min at 50%VO2max after 7 days with or without taurine supplementation. Exercise tended to reduce the blood glucose concentration, whereas taurine significantly prevented this decline. Exercise significantly increased plasma glucagon concentrations in both groups to a similar degree. Serum insulin concentrations did not differ during exercise under both conditions. Taurine supplementation respectively significantly inhibited and tended to inhibit the plasma noradrenaline and adrenaline concentrations increased by exercise. These results suggest that taurine supplementation can maintain the blood glucose concentration during prolonged exercise through enhanced catecholamine sensitivity.
A number of studies have described typical scapular kinematics during arm elevation in adults. However, spinal structure and function differ between normal and elderly adults. To our knowledge, trunk kinematics during arm elevation in the elderly has never been clarified. The purpose of this study was to describe and compare the kinematics patterns of the trunk during arm elevation between normal and elderly adults. Forty-one normal adults (14 male and 27 female, mean age 22.1±1.1 years) and twenty-eight elderly adults (8 male and 20 female, mean age 75.8±7.2 years) participated in this study. The kinematics data were collected using an analog digital measuring device to record the sagittal outline of the back by using the Spinal Mouse system (Idiag AG, Switzerland). Subjects were instructed to raise their arm in the scapular plane, and measurements were performed with the arm in the dependent position, at 0, 30, 60, 90, 120, 150 degrees of abduction, and maximum abduction. The normal adult group demonstrated a significant decrease in thoracic kyphosis at 150 degrees and maximum abduction, and an increase in pelvic tilt at the maximum abduction ; while the elderly group showed no significant differences. This study demonstrates that there are significant differences in thoracic and pelvic kinematics patterns between normal adults and elderly adults. From a clinical prospective, these results can be applied to improve shoulder movements in the elderly.
This prospective study was designed to clarify the association between the incidence of falls and physical fitness in healthy community-dwelling elderly people without history of fall-related injuries within 1-5 years before the baseline assessment. Six hundred and one elderly subjects aged 60-79 years who lived independently participated in baseline assessments from March 2002 to March 2004, and were followed up for one year to detect falling. Demographic items (age and sex), chronic disease, self-rated health, difficulty in performing any activity, tendency to stay at home, body mass index (BMI), %vital capacity, handgrip and knee extension strength, stepping rate, one-leg standing with eyes opened, trunk flexion at sitting position, maximum walking speed, instrumental activity of daily living (IADL), and General Health Questionnaire (GHQ30) were assessed at baseline. Four hundred and eighty-one participants (80.0%) completed the 1-year follow-up. The fall incidence was 13.1%. In men, fallers had lower BMI and decreased maximum walking speed, however, neither showed significant odds ratio (OR) for fall. In women, fallers had lower knee extension strength and the ratio of weak side to strong side (WS/SS ratio) in knee extension strength compared to non-fallers. The age-adjusted OR for fallers in the lowest quartile (knee extension strength＜0.681kg/BW) was 3.07 (95%CI : 1.02-9.22) compared to highest quartile (＞0.980 kg/BW), while the multiple-adjusted OR was not significant (OR＝2.88, 95%CI : 0.94-8.79). However, the multiple-adjusted OR for fallers in the lowest quartile of the WS/SS ratio in knee extension strength (＜0.771) was 4.49 (95%CI : 1.40-14.37) compared to highest quartile (＞0.947).As for conclusion, without history of fall-related injuries, only a weak association between falls and physical fitness was observed in men. In women, the unbalanced knee extension strength was associated with falls. The WS/SS ratio in knee extension strength might be a key factor in predicting falls in women.