To compare the effect of static holds and continuous passive motion on stiffness and force relaxation of the soft tissue structures resisting ankle joint dorsiflexion. This study used a randomized repeated measures trial design. Twenty-four asymptomatic subjects (15 males and 8 females) with a mean age of 26 yr participated. A Kin-Com dynamometer was used to measure the stiffness and force relaxation response of tissues about the ankle joint in response to a plantar flexor stretch. A comparison was made of the response for a 1 x 60-s hold, 2 x 30-s holds, 4 x 15-s holds, and continuous passive motion for 60 s. All subjects undertook all conditions. The main outcome measures were 1) stiffness at the ankle joint as it moved to 80% of the maximum range of dorsiflexion, and 2) the decrease in force at 80% of the maximum range of motion of the ankle joint. Stiffness was decreased significantly (P < 0.05) for the continuous passive motion condition only. The mean magnitude of the decrease in stiffness was 16%. Across hold times, force decreased significantly (P < 0.05). Bonferonni contrasts indicated that there was a significant difference (P < 0.05) between the continuous passive motion condition and all other hold conditions. There were no significant differences (P > 0.05) between the 4 x 15-s, 2 x 30-s, and 1 x 60-s holds. The magnitude of the decline in force was 10.5%, 21.5%, 21.7%, and 19% for the 0-, 15-, 30-, and 60-s holds, respectively. The greatest decreases in tension were achieved in the first 20 s of a hold. If decreasing stiffness is a key aim of a stretching program, the findings indicate that continuous motion is more effective than holds. In contrast, if relaxation of peak tension is the main aim, then holds are most effective.

HOPKINS, W. G., and D. J. HEWSON. Variability of competitive performance of distance runners. Med. Sci. Sports Exerc., Vol. 33, No. 9, 2001, pp. 1588–1592. The typical variation in an athlete’s performance from race to race sets a benchmark for assessing the utility of performance tests and the magnitude of factors affecting medal prospects. We report here the typical variation in competitive performance of endurance runners. Repeated-measures analysis of log-transformed official race times provided the typical within-athlete variation in performance as coefficients of variation (CV). The types of race were cross-country runs (4 races over 9 wk), summer road runs (5 races over 4 wk), winter road runs (4 races over 9 wk), half marathons (3 races over 13 wk and 2 races over 22 wk), and marathons (2 races over 22 wk). Typical variation of times for the fastest quartile of male runners was 1.2–1.9% in the cross-country and road runs, 2.7% and 4.2% in half marathons, and 2.6% in marathons. Times for the slower half of runners in most events were more variable than those of the faster half (ratio of slower/faster CV, 1.0–2.3). Times of younger adult runners were more variable than times of older runners (ratio of younger/older CV, 1.1–1.8). Times of male runners were generally more variable than those of female runners (ratio of male/female CV, 0.9–1.7). Tests of endurance power suitable for assessing the smallest worthwhile changes in running performance for top runners need CV ≤ 2.5% and ≤ 1.5% for tests simulating half or full marathons and shorter running races, respectively. Most of the differences in variability of race times between types of race, ability groups, age groups, and sexes probably arise from differences in competitive experience and attitude toward competing.

This trial represents the final stage of the CARESSES project which aimed to develop and evaluate a culturally competent artificial intelligent system embedded into social robots to support older adult wellbeing. A parallel group, single-blind randomised controlled trial was conducted across older adult care homes in England and Japan. Participants randomly allocated to the Experimental Group or Control Group 1 received a Pepper robot for up 18 h across 2 weeks. Two versions of the CARESSES artificial intelligence were tested: a fully culturally competent system (Experimental Group) and a more limited version (Control Group 1). Control Group 2 (Care As Usual) participants did not receive a robot. Quantitative outcomes of interest reported in the current paper were health-related quality of life (SF-36), loneliness (ULS-8), and perceptions of robotic cultural competence (CCATool-Robotics). Thirty-three residents completed all procedures. The difference in SF-36 Emotional Wellbeing scores between Experimental Group and Care As Usual participants over time was significant (F[1] = 6.614, sig = .019, η_p² = .258), as was the comparison between Any Robot used and Care As Usual (F[1] = 5.128, sig = .031, η_p² = .146). There were no significant changes in SF-36 physical health subscales. ULS-8 loneliness scores slightly improved among Experimental and Control Group 1 participants compared to Care As Usual participants, but this was not significant. This study brings new evidence which cautiously supports the value of culturally competent socially assistive robots in improving the psychological wellbeing of older adults residing in care settings.

Background: The study of balance using stabilogram analysis is of particular interest in the study of falls. Although simple statistical parameters derived from the stabilogram have been shown to predict risk of falls, such measures offer little insight into the underlying control mechanisms responsible for degradation in balance. In contrast, fractal and non-linear time-series analysis of stabilograms, such as estimations of the Hurst exponent (H), may provide information related to the underlying motor control strategies governing postural stability. In order to be adapted for a home-based follow-up of balance, such methods need to be robust, regardless of the experimental protocol, while producing time-series that are as short as possible. The present study compares two methods of calculating H: Detrended Fluctuation Analysis (DFA) and Stabilogram Diffusion Analysis (SDA) for elderly and control subjects, as well as evaluating the effect of recording duration. Methods: Centre of pressure signals were obtained from 90 young adult subjects and 10 elderly subjects. Data were sampled at 100 Hz for 30 s, including stepping onto and off the force plate. Estimations of H were made using sliding windows of 10, 5, and 2.5 s durations, with windows slid forward in 1-s increments. Multivariate analysis of variance was used to test for the effect of time, age and estimation method on the Hurst exponent, while the intra-class correlation coefficient (ICC) was used as a measure of reliability. Results: Both SDA and DFA methods were able to identify differences in postural stability between control and elderly subjects for time series as short as 5 s, with ICC values as high as 0.75 for DFA. Conclusion: Both methods would be well-suited to non-invasive longitudinal assessment of balance. In addition, reliable estimations of H were obtained from time series as short as 5 s.