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Daniel F. Perez, Paul G. Ritvo, Patrick E. Brown, Eric Holowaty and Chris Ardern

Background:

The role of social-environmental factors in physical activity (PA) within lower income and ethnic minority populations is understudied. This study explored correlates of age-related PA and perceived walkability (PW).

Methods:

Cross-sectional data (N = 401 women; ≥18 y) were collected within the Jane-Finch community in Toronto, Ontario using questionnaires. Generalized additive models, an extension to multiple regression, were used to estimate effect sizes and standard errors.

Results:

Significant interactions between native language and car access (CA) were observed in PA variation across the lifespan. Individuals were evenly distributed across 4 comparison groups: 29.2% English-NoCA, 24.1% English-CA, 20.7% Non-English-NoCA, and 26.0% NonEnglish-CA. Risk of sedentariness increased with age for native English speakers > 50 years, but appears unaffected by age for other groups. English speakers without CA < 60 years appear least likely to be sedentary, followed by English speakers with CA. In general, an active individual at the 75th percentile of social support for exercise would have 1.62 (CI: 1.22−2.17) times the MET-Hours of PA than an active individual at the 25th percentile of SSE.

Conclusions:

English language facility and car access moderate relationships of social-environmental factors and PA. Further investigation is required to better understand correlates of PA for women in this demographic.

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Nabil Ilmane and Jacques LaRue

The aim of this experiment was to explore the behavioral effects of various temporal pressures on the anticipatory postural adjustments (APAs) in a complex task. Eighteen handball players performed a handball direct throw in three conditions of temporal pressure: (1) a reactive condition (RC), the throw was initiated as quickly as possible following a visual stimulus; (2) an anticipation-coincidence condition (AC), by synchronizing the impact of the ball with the passage of a visual mobile on a target; and (3) a self-initiated (SI) throw. The whole-body postural oscillation and the acceleration of the wrist were measured before and during the throwing action. Results showed that the delays between the onsets of the postural and focal activities were significantly different between RC and both the SI and the AC conditions. Movement time, time to peaks (negative and positive), are shorter in the RC, intermediate in the AC, and longer in the SI condition. Variability was significantly larger in AC in comparison with RC and SI. These results support the existence of different control modes triggered by the temporal pressure; they demonstrate that these control modes can be generalized to complex intentional movements such as the throwing skill and to an anticipation-coincidence situation.

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Amy K. Hegarty, Max J. Kurz, Wayne Stuberg and Anne K. Silverman

The goal of this pilot study was to characterize the effects of gait training on the capacity of muscles to produce body accelerations and relate these changes to mobility improvements seen in children with cerebral palsy (CP). Five children (14 years ± 3 y; GMFCS I-II) with spastic diplegic CP participated in a 6-week gait training program. Changes in 10-m fast-as-possible walking speed and 6-minute walking endurance were used to assess changes in mobility. In addition, musculoskeletal modeling was used to determine the potential of lower-limb muscles to accelerate the body’s center of mass vertically and forward during stance. The mobility changes after the training were mixed, with some children demonstrating vast improvements, while others appeared to be minimal. However, the musculoskeletal results revealed unique responses for each child. The most common changes occurred in the capacity for the hip and knee extensors to produce body support and the hip flexors to produce body propulsion. These results cannot yet be generalized to the broad population of children with CP, but demonstrate that therapy protocols may be enhanced by modeling analyses. The pilot study results provide motivation for gait training emphasizing upright leg posture, mediolateral balance, and ankle push-off.

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Jason D. Vescovi, Olesya Falenchuk and Greg D. Wells

Purpose:

Blood lactate concentration, [BLa], after swimming events might be influenced by demographic features and characteristics of the swim race, whereas active recovery enhances blood lactate removal. Our aims were to (1) examine how sex, age, race distance, and swim stroke influenced [BLa] after competitive swimming events and (2) develop a practical model based on recovery swim distance to optimize blood lactate removal.

Methods:

We retrospectively analyzed postrace [BLa] from 100 swimmers who competed in the finals at the Canadian Swim Championships. [BLa] was also assessed repeatedly during the active recovery. Generalized estimating equations were used to evaluate the relationship between postrace [BLa] with independent variables.

Results:

Postrace [BLa] was highest following 100–200 m events and lowest after 50 and 1500 m races. A sex effect for postrace [BLa] was observed only for freestyle events. There was a negligible effect of age on postrace [BLa]. A model was developed to estimate an expected change in [BLa] during active recovery (male = 0; female = 1): [BLa] change after active recovery = –3.374 + (1.162 × sex) + (0.789 × postrace [BLa]) + (0.003 × active recovery distance).

Conclusions:

These findings indicate that swimmers competing at an elite standard display similar postrace [BLa] and that there is little effect of age on postrace [BLa] in competitive swimmers aged 14 to 29 y.

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Robert J. Vallerand, Pasquale G. Colavecchio and Luc G. Pelletier

This paper introduces a model on psychological momentum (PM) in sport (Vallerand, 1985, 1987) and presents preliminary results supportive of the model. The antecedents-consequences PM model postulates that PM refers to perceptions that the actor is progressing toward his/her goal. The model emphasizes that PM perception must be distinguished from its antecedents and performance consequences. In addition, personal and situational variables are hypothesized to lead to perceptions of PM while personal and contextual variables are hypothesized to moderate the PM-performance relationship. This study tested hypotheses derived from the model with respect to the impact of antecedent variables on PM perceptions and attempted to ascertain the link between PM perceptions and performance inferences. Subjects with high and low tennis experience read scenarios depicting a match between two tennis players wherein the score was tied at 5 all in the first set. Two versions of the scenarios were prepared so that the momentum pattern as manipulated by the score configuration was either present or absent. Results revealed that the presence of a PM pattern led to enhanced PM perceptions. In addition, both the score configuration and the experience variables led to inferences that the player having PM should win the first set, and there were some limited indications that such inferences generalized to winning the match. Results are discussed in light of the PM model, and directions for future research are underscored.

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Bert Steenbergen and John van der Kamp

We investigated attentional processes that support the performance of high-skilled soccer players with hemiparetic cerebral palsy. Participants (N = 10) dribbled a slalom course as quickly and accurately as possible under two attentional-focus manipulation conditions. In the task-relevant focus condition, they attended to the foot that was in contact with the ball, whereas in the task-irrelevant focus condition, they monitored a series of words played on a tape. The time taken to complete the slalom course was registered. Performances of individuals with left and right hemiparesis were compared to explore differential effects of hemispheric lesion. The high-skilled players with congenital hemiparesis showed similar attentional-focus effects as those previously reported in the literature for high-skilled players without neurological disorders (Beilock et al., 2002; Ford et al., 2005). Task-relevant focus increased dribbling time, whereas a task-irrelevant focus did not result in a significant change in dribbling time. These findings generalized to each of the five participants with left hemiparesis (i.e., damage to the right hemisphere). By contrast, the effects of a task-relevant focus were less consistent for participants with right hemiparesis (i.e., left-hemisphere damage). This corroborates suggestions that the reinvestment of procedural knowledge is a left-lateralized function. The implications for the training of individuals with congenital brain damage are discussed.

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Mary O. Hearst, John R. Sirard, Leslie Lytle, Donald R. Dengel and David Berrigan

Background:

The association of physical activity (PA), measured 3 ways, and biomarkers were compared in a sample of adolescents.

Methods:

PA data were collected on 2 cohorts of adolescents (N = 700) in the Twin Cities, Minnesota, 2007–2008. PA was measured using 2 survey questions [Modified Activity Questionnaire (MAQ)], the 3-Day Physical Activity Recall (3DPAR), and accelerometers. Biomarkers included systolic (SBP) and diastolic blood pressure (DBP), lipids, percent body fat (%BF), and body mass index (BMI) percentile. Bivariate relationships among PA measures and biomarkers were examined followed by generalized estimating equations for multivariate analysis.

Results:

The 3 measures were significantly correlated with each other (r = .22–.36, P < .001). Controlling for study, puberty, age, and gender, all 3 PA measures were associated with %BF (MAQ = −1.93, P < .001; 3DPAR = −1.64, P < .001; accelerometer = −1.06, P = .001). The MAQ and accelerometers were negatively associated with BMI percentile. None of the 3 PA measures were significantly associated with SBP or lipids. The percentage of adolescents meeting the national PA recommendations varied by instrument.

Conclusions:

All 3 instruments demonstrated consistent findings when estimating associations with %BF, but were different for prevalence estimates. Researchers must carefully consider the intended use of PA data when choosing a measurement instrument.

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Han C.G. Kemper, Jos W.R. Twisk and Willem van Mechelen

In the Amsterdam Growth And Health Longitudinal Study (AGAHLS), a group of approximately 650 12- to 14-year-old boys and girls was followed in their growth, and development of their health their lifestyle including diet, physical activity and smoking. One of the main interests was the change in their aerobic fitness. From 12 to 36 years of age in total, eight repeated measurements were performed to measure peak oxygen uptake (peak VO2). In this study the data of peak VO2 are revisited and extended: We made use of all collected data as a mixed longitudinal design including cross-sectionally measured subjects as well as longitudinally measured subjects. This led to the availability of 1,194 boys and 1356 girls. With generalized estimating equations (GEE) the longitudinal changes with chronological age and differences between boys and girls were analyzed. Teenage boys and girls increased their peak VO2 (ml/min) significantly (p < .001) until age 14 in girls and until age 17 in boys. However peak VO2 relative to bodyweight (peak VO2/BW) had significantly (p < .001) decreased over the whole age range from 12 to 36 in both sexes. Vigorous physical activity (VPA) also showed a decrease and was significantly (p < .001) related with lower peak VO2/BW (Beta = 0.001). This relation was stronger in boys than in girls. Because at the start of AGAHLS no fast responding metabolic instruments were available, future longitudinal studies about aerobic fitness should include also measurement of VO2 kinetics.

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Gurtej S. Grewal, Rachel Baisch, Jacqueline Lee-Eng, Stephaine Wu, Beth Jarrett, Neil Humble and Bijan Najafi

Context:

Improvements in postural stability in figure skaters can play a significant role in performance, as well as reducing fall risk.

Objective:

To explore the effect of custom foot insoles on postural stability in advanced figure skaters.

Design:

Exploratory study.

Setting:

Out of laboratory.

Participants:

Nine advanced figure skaters were recruited and 7 completed the study (age 38 ± 18.5 y, body-mass index 25 ± 3.6 kg/m2).

Intervention:

Custom foot insoles.

Main Outcome Measures:

Primary outcome of changes in postural stability (PS) quantified by center-of-mass sway with secondary outcomes of ankleand hip-joint sway and joint range of motion. Sway measurements were assessed using body-worn sensors while participants wore skates on ice. PS was assessed in single-leg stance, as well as during gliding on the dominant foot.

Results:

A significant improvement in static PS was observed after 6-wk use of custom insoles. Center-of-mass sway reduced significantly on average by 48.44% (P = .023), and ankle-joint sway reduced by 45.7% (P = .05) during single-leg-stance balance measurements. During the gliding maneuver nonsignificant changes were observed for both ankle- and knee-joint range of motion.

Conclusion:

The results of this study suggest proof of concept toward benefits of custom insoles in improving postural stability in advanced figure skaters. To generalize the findings, randomized controlled trials with larger sample sizes are warranted.

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Jason A. Mendoza, David Cowan and Yan Liu

Background:

Few reports examined long term predictors of children’s active commuting to school (walking or cycling to school, ACS).

Purpose:

To identify predictors of ACS over 1 school year among a sample of children with relatively high rates of ACS.

Methods:

Parents were surveyed in September 2010 (Time 1) and April 2011 (Time 2). The dependent variable was children’s commuting mode to school (active versus passive). Independent variables included: 1) parents’ outcome expectations (from Social Cognitive Theory: the expected risks/benefits for their child doing ACS), 2) distance to school, 3) participation in an adult-led walk to school group, 4) temperature, and 5) child demographics. Generalized mixed-models estimated odds ratios for ACS (n = 369 or 49.7% of Time 1 respondents).

Results:

Males (OR = 2.59, 95% CI [1.57–4.30]), adult-led walk to school group participation (OR = 1.80, 95% CI [1.14–2.86]), parents’ outcome expectations (OR = 1.26, 95% CI [1.14–1.39]), temperature (OR = 1.03, 95% CI [1.01–1.07), distance to school (OR = 0.23, 95% CI [0.14–0.37]), and Latino ethnicity (OR = 0.28, 95% CI [0.12–0.65]) were associated with ACS.

Conclusions:

Programs and policies sensitive to parents’ concerns (eg, adult-led walk to school groups) and targeting Latinos and girls appear promising for increasing ACS.