Search Results

Purpose: The use of self-efficacy to predict physical activity has a long history. However, this relationship is complex, as self-efficacy is thought to influence and be influenced by physical activity. The directionality of the self-regulatory efficacy (SRE) and physical activity relationship was examined using a cross-lagged design. A secondary purpose was to examine these relationships across differing weather conditions. Methods: Canadian adolescents (N = 337; aged between 13 and 18 years) completed the physical activity and SRE measures 4 times during a school year. Structural equation modeling was used to perform a cross-lag analysis. Results: The relationships between physical activity and SRE appeared to be weather dependent. During a more challenging weather period (eg, cold weather), the relationship between physical activity and SRE was bidirectional. However, no relationship emerged when the 2 constructs were assessed during a more optimal weather period (eg, warm weather). Conclusions: Some support has been provided for the bidirectional nature of the relationship between physical activity and SRE. The relationship appeared to be qualified by climate considerations, suggesting that future research examine how weather may relate not just to physical activity but also to the correlates of physical activity.

Research has identified an increased risk of lower extremity injury postconcussion, which may be due to aberrant biomechanics during dynamic tasks. The purpose of this study was to compare the drop landing biomechanics between individuals with and without a concussion history. Twenty-five individuals with and 25 without a concussion history were matched on age (±3 y), sex, and body mass index (±1 kg/m²). Three-dimensional landing biomechanics were recorded to obtain dependent variables (peak vertical ground reaction force, loading rate, knee flexion angle and external moment, knee abduction angle and external moment, and knee flexion and abduction angle at ground contact). A 1-way multivariate analysis of variance compared outcomes between groups. There was no difference in drop landing biomechanics between individuals with and without a concussion history (F _10,39 = 0.460, P = .877, Wilk Λ = .918). There was an effect of time since concussion on knee flexion characteristics. Time since most recent concussion explained a significant amount of variation in both peak (ΔR ² = .177, β = −0.305, ΔP = .046) and initial ground contact (ΔR ² = .292, β = −0.204, ΔP = .008) knee flexion angle after covarying for sex and body mass index. Therefore, time since concussion should be considered when evaluating biomechanical patterns.

Context: Induced mental fatigue negatively impacts sport performance and neurocognition. However, it is unclear how induced mental fatigue influences landing biomechanics. The purpose of this study was to examine the influence of mental fatigue on drop landing biomechanics in individuals with and without a concussion history. Design: Crossover design. Methods: Forty-eight (24 per group) recreationally active individuals were matched on age (±3 y), sex, and body mass index (±1 kg/m²). All participants completed an experimental (30-min Stroop task) and control (30-min reading magazines) intervention on separate days separated by a minimum of 24 hours. Drop landings were performed before and after both interventions. Outcomes included peak vertical ground reaction force (vGRF), vertical loading rate (VLR), knee flexion angle, knee abduction angle, external knee flexion moment, external knee abduction moment, and initial ground contact knee flexion and knee abduction angles. Separate 2 (group) × 2 (intervention) between-within analyses of covariance compared drop landing outcomes. Each group’s average pre-Stroop and premagazine outcomes were covariates. Results: There was a significant interaction for vGRF (P = .033, ${\eta }_{\mathrm{p}}^2=.097$ ) and VLR (P = .0497, ${\eta }_{\mathrm{p}}^2=.083$ ). The vGRF simple effects were not statistically significantly (P range = .052–.325). However, individuals with a concussion history displayed a medium effect size for greater vGRF post-Stroop compared with their own postmagazine vGRF (mean difference (95% confidence interval [95% CI] = 0.163 (–0.002 to 0.327) bodyweight (BW), p =.052, ${\eta }_{\mathrm{p}}^2=.081$ . In contrast, the control group displayed a small effect size (mean difference [95% CI] = 0.095 [–0.069 to 0.259] BW, p =.251, ${\eta }_{\mathrm{p}}^2=.029$ ). Individuals with a concussion history displayed greater VLR post-Stroop compared with controls (mean difference [95% CI], 26.29 [6.19 to 46.40] BW/s, P = .012, ${\eta }_{\mathrm{p}}^2=.134$ ) and their own postmagazine values (mean difference [95% CI] = 32.61 [7.80 to 57.42] BW/s, p =.011, ${\eta }_{\mathrm{p}}^2=.135$ ). Conclusion: Mental fatigue leads to greater VLR for individuals with a concussion history. Athletic competition and activities of daily living can increase mental fatigue. Training programs may seek to teach mental fatigue reducing strategies to athletes with a concussion history.

The purpose of this study was to investigate youth athletes’ perceptions of group norms for competition, practice, and social setting contexts in relation to personal and social factors. A secondary purpose of this study was to examine the interactions of the personal and situation factors on perceptions of group norms. Participants included 424 athletes from 35 high school sport teams who completed a survey assessing team norms in competition, practice, and social settings. Multilevel analysis results revealed differences in group norms by gender as well as gender by team tenure and gender by sport type interactions. Female teams held higher perceptions of norms for competition, practice, and social settings than male teams. Interactions between gender and team tenure and gender and sport type revealed significant differences in practice norms. No differences were found in norms by group size. The findings suggest that examining the characteristics of the team members (i.e., gender, team tenure) and team (i.e., type of sport) may enhance our understanding of group norms in a youth sport setting.