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Ferdous Wahid, Rezaul Begg, Noel Lythgo, Chris J. Hass, Saman Halgamuge and David C. Ackland

Normalization of gait data is performed to reduce the effects of intersubject variations due to physical characteristics. This study reports a multiple regression normalization approach for spatiotemporal gait data that takes into account intersubject variations in self-selected walking speed and physical properties including age, height, body mass, and sex. Spatiotemporal gait data including stride length, cadence, stance time, double support time, and stride time were obtained from healthy subjects including 782 children, 71 adults, 29 elderly subjects, and 28 elderly Parkinson’s disease (PD) patients. Data were normalized using standard dimensionless equations, a detrending method, and a multiple regression approach. After normalization using dimensionless equations and the detrending method, weak to moderate correlations between walking speed, physical properties, and spatiotemporal gait features were observed (0.01 < |r| < 0.88), whereas normalization using the multiple regression method reduced these correlations to weak values (|r| < 0.29). Data normalization using dimensionless equations and detrending resulted in significant differences in stride length and double support time of PD patients; however the multiple regression approach revealed significant differences in these features as well as in cadence, stance time, and stride time. The proposed multiple regression normalization may be useful in machine learning, gait classification, and clinical evaluation of pathological gait patterns.

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Alex V. Rowlands

2016 has been an exciting year for research in physical activity, inactivity and health. Recognition of the importance of all physical behaviors (physical activity, sedentary time and sleep) across the 24-hr day continues to grow. Notable advances have included: applications of recent methodological innovations that account for the codependence of the behaviors in the finite 24-hr period showing that the balance of these behaviors is associated with health; methodological innovations focusing on the classification of behaviors and/or quantification of the 24-hr diurnal activity pattern; and a series of systematic reviews that helped provide the evidence base for the release of the innovative 24-hr movement guidelines earlier this year. This commentary focuses on just two of these papers: the first by Goldsmith and colleagues who demonstrate a new statistical method that exploits the time series nature of accelerometer data facilitating new insights into time-specific determinants of children’s activity patterns and associations with health; the second by Tremblay and colleagues who describe the evidence base for associations between each physical behavior and children’s health, the emerging evidence base for associations between the balance of behaviors and health, and development of the world’s first 24-hr movement guidelines.

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Thomas Paulson and Victoria Goosey-Tolfrey

Despite the growing interest in Paralympic sport, the evidence base for supporting elite wheelchair sport performance remains in its infancy when compared with able-bodied (AB) sport. Subsequently, current practice is often based on theory adapted from AB guidelines, with a heavy reliance on anecdotal evidence and practitioner experience. Many principles in training prescription and performance monitoring with wheelchair athletes are directly transferable from AB practice, including the periodization and tapering of athlete loads around competition, yet considerations for the physiological consequences of an athlete’s impairment and the interface between athlete and equipment are vital when targeting interventions to optimize in-competition performance. Researchers and practitioners are faced with the challenge of identifying and implementing reliable protocols that detect small but meaningful changes in impairment-specific physical capacities and on-court performance. Technologies to profile both linear and rotational on-court performance are an essential component of sport-science support to understand sport-specific movement profiles and prescribe training intensities. In addition, an individualized approach to the prescription of athlete training and optimization of the “wheelchair–user interface” is required, accounting for an athlete’s anthropometrics, sports classification, and positional role on court. In addition to enhancing physical capacities, interventions must focus on the integration of the athlete and his or her equipment, as well as techniques for limiting environmental influence on performance. Taken together, the optimization of wheelchair sport performance requires a multidisciplinary approach based on the individual requirements of each athlete.

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Erik J. Timmermans, Suzan van der Pas, Elaine M. Dennison, Stefania Maggi, Richard Peter, Maria Victoria Castell, Nancy L. Pedersen, Michael D. Denkinger, Mark H. Edwards, Federica Limongi, Florian Herbolsheimer, Mercedes Sánchez-Martínez, Paola Siviero, Rocio Queipo, Laura A. Schaap, Dorly J.H. Deeg and for the EPOSA research group

Background:

Older adults with osteoarthritis (OA) often report that their disease symptoms are exacerbated by weather conditions. This study examines the association between outdoor physical activity (PA) and weather conditions in older adults from 6 European countries and assesses whether outdoor PA and weather conditions are more strongly associated in older persons with OA than in those without the condition.

Methods:

The American College of Rheumatology classification criteria were used to diagnose OA. Outdoor PA was assessed using the LASA Physical Activity Questionnaire. Data on weather parameters were obtained from weather stations.

Results:

Of the 2439 participants (65–85 years), 29.6% had OA in knee, hand and/or hip. Participants with OA spent fewer minutes in PA than participants without OA (Median = 42.9, IQR = 20.0 to 83.1 versus Median = 51.4, IQR = 23.6 to 98.6; P < .01). In the full sample, temperature (B = 1.52; P < .001) and relative humidity (B = –0.77; P < .001) were associated with PA. Temperature was more strongly associated with PA in participants without OA (B = 1.98; P < .001) than in those with the condition (B = 0.48; P = .47).

Conclusions:

Weather conditions are associated with outdoor PA in older adults in the general population. Outdoor PA and weather conditions were more strongly associated in older adults without OA than in their counterparts with OA.

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Christiana M.T. van Loo, Anthony D. Okely, Marijka Batterham, Tina Hinkley, Ulf Ekelund, Soren Brage, John J. Reilly, Gregory E. Peoples, Rachel Jones, Xanne Janssen and Dylan P. Cliff

Background:

To validate the activPAL3 algorithm for predicting metabolic equivalents (TAMETs) and classifying MVPA in 5- to 12-year-old children.

Methods:

Fifty-seven children (9.2 ± 2.3y, 49.1% boys) completed 14 activities including sedentary behaviors (SB), light (LPA) and moderate-to-vigorous physical activities (MVPA). Indirect calorimetry (IC) was used as the criterion measure. Analyses included equivalence testing, Bland-Altman procedures and area under the receiver operating curve (ROC-AUC).

Results:

At the group level, TAMETs were significantly equivalent to IC for handheld e-game, writing/coloring, and standing class activity (P < .05). Overall, TAMETs were overestimated for SB (7.9 ± 6.7%) and LPA (1.9 ± 20.2%) and underestimated for MVPA (27.7 ± 26.6%); however, classification accuracy of MVPA was good (ROC-AUC = 0.86). Limits of agreement were wide for all activities, indicating large individual error (SB: −27.6% to 44.7%; LPA: −47.1% to 51.0%; MVPA: −88.8% to 33.9%).

Conclusions:

TAMETs were accurate for some SB and standing, but were overestimated for overall SB and LPA, and underestimated for MVPA. Accuracy for classifying MVPA was, however, acceptable.

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Joanna E. Gelinas and Greg Reid

The purpose was to determine whether traditional learn-to-swim progressions, leading to a 10-m front and 10-m back swim, were developmentally valid for children with physical disabilities. Forty children (22 boys, 18 girls) ages 5 to 12 years participated. They were classified according to disability type, functional sport classification, mode of ambulation, and flotation device use. Developmental validity was assessed by testing the children on rhythmic breathing, front float, front glide, front swim, back float, back glide, and back swim. Each skill was deemed successful if the child accomplished all performance criteria of that skill. Atypical progression was evident if a child performed a skill without the ability to perform skills previously listed in that progression. Atypical progression occurred in 32 (80%) children in the front skills and 22 (55%) in the back skills, which indicates that the traditional learn-to-swim progressions for both the 10-m front swim and the 10-m back swim were not developmentally valid for most children with physical disabilities in the conducted research.

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Ashley J. Cripps, Luke Hopper and Christopher Joyce

Purpose:

To confirm the effect of maturational differences on anthropometric and physical testing and explore the effect of maturation on technical skill and coaches’ perceptions of skill in adolescent Australian footballers.

Methods:

Athletes were recruited from a semielite under 16 competition (n = 94, age 15.7 ± 0.3 years) and completed anthropometric, physical, and technical skill tests. Coaches from each team provided subjective ratings of athletes’ technical skills. Maturation groups were derived from years from peak height velocity estimates, with classifications either later, average or earlier maturing.

Results:

Effect size comparisons revealed very large to moderate effects between groups for anthropometric measures and performance in sprint and jump tasks. Small to moderate effects were reported between groups for coaches’ perceptions of skill, with the earlier maturing group perceived to have better overall technical skills, marking and ball winning abilities. Small to trivial effects were reported for performance in the technical skill tests.

Conclusion:

Despite no differences in skill tests, earlier maturing athletes may be afforded significant selection and competition advantages due to advanced physical capacities and coaches’ perceptions of skill.

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David A. Rowe, Charles D. Kemble, Terrance S. Robinson and Matthew T. Mahar

Objective:

To determine the day-to-day variability of older adults’ physical activity, and to evaluate the accuracy of the 10,000-step goal for classifying whether older adults obtain 30 min of MVPA.

Methods:

Ninety-one adults ages over 60 y wore a Yamax pedometer and Actigraph accelerometer for 7 days. Interday reliability was estimated via two-way ANOVA ICCs, and classification accuracy was evaluated via sensitivity, specificity, and ROC curve analysis.

Results:

Interday reliability was high; four of five outcome measures had a reliability of ≥.80 with only 2 days of data. The 10,000-step cut point had high accuracy for identifying days with less than 30 min of MVPA, but poor accuracy for identifying days with more than 30 min of MVPA.

Conclusions:

Day-to-day variability in physical activity is lower in older adults than other age groups. The 10,000-step goal is inadequate for determining whether daily physical activity includes 30 min of MVPA in this population.

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Gregory Shaw, Gary Slater and Louise M. Burke

Thirty nine elite Australian swimmers (13 AIS, 26 OTHER) completed a standardized questionnaire regarding their supplement use during a pre competition camp. The data were compared with a similar study conducted 11 years earlier (11 AIS, 23 OTHER) and framed around the classification system of the Sport Supplement Program of the Australian Institute of Sport. The prevalence of supplement use remained constant over time (2009: 97%, 1998: 100%). However, the current swimmers used a greater number of dietary supplements (9.2 ± 3.7 and 5.9 ± 2.9; p = .001), accounted for by an increase in the reported use of supplements with a greater evidence base (Sports Foods, Ergogenics, and Group B supplements). In contrast, fewer supplements considered less reputable (Group C and D) were reported by the 2009 cohort (0.7 ± 1.0 and 1.6 ± 1.3; p = .003). AIS swimmers reported a greater use of Ergogenics (4.3 ± 1.8 and 3.1 ± 1.7; p = .002), and less use of Group C and D supplements overall (0.8 ± 1.2 and 1.3 ± 1.2; p = .012), which was explained primarily by a smaller number of these supplements reported by the 2009 group (1998 AIS: 1.5 ± 1.4, 2009 AIS: 0.2 ± 0.6; p = .004). Although the prevalence of supplement use has not changed over time, there has been a significant increase in the number and type of products they are using. The potential that these changes can be attributed to a Sports Supplement Program merit investigation.

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Gail M. Dummer, Martha E. Ewing, Rochelle V. Habeck and Sara R. Overton

The attributions of 147 athletes with cerebral palsy who participated in the 1985 National Cerebral Palsy/Les Autres Games were investigated following competition relative to their reactions to objectively and subjectively defined success or failure. Attributions were the dependent variable in a 2 × 2 (More-Disabled/Less-Disabled × Win/Loss) MANOVA. Attributions were also analyzed in a 2 × 4 (More-Disabled/Less-Disabled × Satisfied/Dissatisfied, Winner/Loser) MANOVA designed to determine the influence of perceived success or failure upon causal explanations of performance. There were no significant differences in the use of attributions by gender; however, there were differences in the use of attributions across disability classifications. Disabled winners used both internal and external explanations to a greater degree than losers, which was inconsistent with previous literature. Previous results linking persistence in sport to the use of internal and stable attributions were supported. Subjective outcome, defined in terms of satisfaction with performance, was a more powerful explanation of achievement behavior for the disabled athletes in this study than objective outcome. Satisfaction was associated with demonstration of positive qualities such as using the right strategy and ability, with realistic assessment of ability, and with enjoying competition.