title: The influence of asymptomatic hypermobility on unanticipated cutting biomechanics

authors: Hanzlíková, Ivana

subjects: Science & Technology

abstract: Background:
Generalized joint hypermobility is an important risk factor for knee injuries, including to the anterior cruciate ligament (ACL). Examining movement patterns specific to hypermobile individuals during sport-specific movements could facilitate development of targeted recommendations and injury prevention programs for this population.

Hypothesis:
Asymptomatic hypermobile participants will present kinematics measures suggestive of a greater risk of noncontact knee or ACL injuries.

Study Design:
Cross-sectional study.

Level of Evidence:
Level 3.

Methods:
Forty-two (15 asymptomatic hypermobile and 27 nonhypermobile) individuals performed unanticipated side-step cutting on their dominant and nondominant legs. Ankle, knee, hip, pelvis, and trunk angles in all planes of motion were collected during the first 100 ms after initial contact using a 3-dimensional infrared system. Precontact foot-ground angles were also extracted. Data from hypermobile and nonhypermobile groups were compared using multiple regression models with sex as a confounder. When nonsignificant, the confounder was removed from the model. Effect sizes (Hedge g) were calculated in the presence of significant between-group differences.

Results:
Hypermobile individuals presented with lower minimum knee valgus angles with a mean difference of 3.5° (P = 0.03, Hedge g = 0.69) and greater peak knee external rotation angles with a mean difference of −4.5° (P = 0.04, Hedge g = 0.70) during dominant leg cutting, and lower peak ankle plantarflexion angles with a mean difference of 4.5° (P = 0.03, Hedge g = 0.73) during nondominant leg cutting compared with nonhypermobile individuals.

Conclusion:
Based on current scientific evidence, however, the identified differences are not crucial biomechanical injury risk factors that could predispose asymptomatic hypermobile individuals to noncontact knee or ACL injuries.

Clinical Relevance:
Further research is needed to highlight differences between hypermobility groups. Knowledge of the differences between these groups may change the physical activity recommendations, prevention of injury, and rehabilitation approaches.

text: The influence of asymptomatic hypermobility on unanticipated cutting biomechanics Background:
Generalized joint hypermobility is an important risk factor for knee injuries, including to the anterior cruciate ligament (ACL). Examining movement patterns specific to hypermobile individuals during sport-specific movements could facilitate development of targeted recommendations and injury prevention programs for this population.

Hypothesis:
Asymptomatic hypermobile participants will present kinematics measures suggestive of a greater risk of noncontact knee or ACL injuries.

Study Design:
Cross-sectional study.

Level of Evidence:
Level 3.

Methods:
Forty-two (15 asymptomatic hypermobile and 27 nonhypermobile) individuals performed unanticipated side-step cutting on their dominant and nondominant legs. Ankle, knee, hip, pelvis, and trunk angles in all planes of motion were collected during the first 100 ms after initial contact using a 3-dimensional infrared system. Precontact foot-ground angles were also extracted. Data from hypermobile and nonhypermobile groups were compared using multiple regression models with sex as a confounder. When nonsignificant, the confounder was removed from the model. Effect sizes (Hedge g) were calculated in the presence of significant between-group differences.

Results:
Hypermobile individuals presented with lower minimum knee valgus angles with a mean difference of 3.5° (P = 0.03, Hedge g = 0.69) and greater peak knee external rotation angles with a mean difference of −4.5° (P = 0.04, Hedge g = 0.70) during dominant leg cutting, and lower peak ankle plantarflexion angles with a mean difference of 4.5° (P = 0.03, Hedge g = 0.73) during nondominant leg cutting compared with nonhypermobile individuals.

Conclusion:
Based on current scientific evidence, however, the identified differences are not crucial biomechanical injury risk factors that could predispose asymptomatic hypermobile individuals to noncontact knee or ACL injuries.

Clinical Relevance:
Further research is needed to highlight differences between hypermobility groups. Knowledge of the differences between these groups may change the physical activity recommendations, prevention of injury, and rehabilitation approaches.

year: 2021

title: Influences of catchment and corridor imperviousness on urban stream macroinvertebrate communities at multiple spatial scales

authors: Collier, Kevin J.

subjects: stormwater

abstract: Resolving land cover hierarchy relationships in urban settings is important for defining the scale and type of management required to enhance stream health. We investigated associations between macroinvertebrate assemblages in urban streams of Hamilton, New Zealand, and environmental variables measured at multiple spatial scales comprising (i) local-scale physicochemical conditions, (ii) impervious area in multiple stream corridor widths (30, 50 and 100 m) along segments (sections of stream between tributary nodes) and for entire upstream networks, and (iii) total impervious area in stream segment sub-catchments and upstream catchments. Imperviousness was higher for stream segment subcatchments than for entire catchments because of the agricultural headwaters of some urban streams. Imperviousness declined as corridor width declined at both segment and catchment scales reflecting the vegetated cover along most urban stream gullies. Upstream catchment imperviousness was strongly and inversely correlated with dissolved organic carbon concentration, whereas segment and upstream corridor scales were correlated with water temperature and pH. Corridor imperviousness appeared to be a stronger predictor than catchment imperviousness of Ephemeroptera, Plecoptera and Trichoptera taxa richness and the Quantitative Urban Community Index specifically developed to assess impacts of urbanisation. In contrast, imperviousness at all measured scales added only marginal improvement in assemblage-based models over that provided by the local-scale physicochemical variables of reach width, habitat quality, macrophyte cover, pH and dissolved oxygen concentration. These findings infer variable scales of influence affecting macroinvertebrate communities in urban streams and suggest that it may be important to consider local and corridor factors when determining mechanisms of urbanisation impacts and potential management options.

text: Influences of catchment and corridor imperviousness on urban stream macroinvertebrate communities at multiple spatial scales Resolving land cover hierarchy relationships in urban settings is important for defining the scale and type of management required to enhance stream health. We investigated associations between macroinvertebrate assemblages in urban streams of Hamilton, New Zealand, and environmental variables measured at multiple spatial scales comprising (i) local-scale physicochemical conditions, (ii) impervious area in multiple stream corridor widths (30, 50 and 100 m) along segments (sections of stream between tributary nodes) and for entire upstream networks, and (iii) total impervious area in stream segment sub-catchments and upstream catchments. Imperviousness was higher for stream segment subcatchments than for entire catchments because of the agricultural headwaters of some urban streams. Imperviousness declined as corridor width declined at both segment and catchment scales reflecting the vegetated cover along most urban stream gullies. Upstream catchment imperviousness was strongly and inversely correlated with dissolved organic carbon concentration, whereas segment and upstream corridor scales were correlated with water temperature and pH. Corridor imperviousness appeared to be a stronger predictor than catchment imperviousness of Ephemeroptera, Plecoptera and Trichoptera taxa richness and the Quantitative Urban Community Index specifically developed to assess impacts of urbanisation. In contrast, imperviousness at all measured scales added only marginal improvement in assemblage-based models over that provided by the local-scale physicochemical variables of reach width, habitat quality, macrophyte cover, pH and dissolved oxygen concentration. These findings infer variable scales of influence affecting macroinvertebrate communities in urban streams and suggest that it may be important to consider local and corridor factors when determining mechanisms of urbanisation impacts and potential management options.

year: 2010

title: Context counts : leading educational reform in New Zealand secondary schools

authors: Morrison, Michele

subjects: context

abstract: Educational leadership and organisational literature is replete with syntheses of effective leader behaviours, change sequences and reform models, yet few studies explore the nuanced manner in which individual leaders make sense of and respond to the dynamic influences shaping their thinking and practice over time. In posing the question, how do principals experience leadership during periods of intentional educational change, this study gains insight into the lived experience of five New Zealand secondary school principals as they lead school wide implementation of Phase 5 Te Kotahitanga, a reform initiative designed to reduce disparities in the educational achievement of indigenous Māori students through the introduction of a culturally responsive pedagogy of relations. The case narratives arising from a three year dialogue with participants examine the genesis of each principal’s commitment to equity in educational access, opportunity and outcome; their evolving thinking and practice; and the manner in which people and structures within each school field enable and constrain their leadership endeavours. Findings demonstrate that leading counter-hegemonic change is a situated, complex and demanding undertaking, the intensity of which eludes much of the leadership and change literature. Hermeneutic reading of these rich qualitative accounts of lived experience suggests that, far from being detached observers, leaders both embody and are embedded in context. This exposes the shortcomings of literature that dichotomises the two and makes Bourdieu’s lens on practice as a temporal, embodied, discursive and social activity an important heuristic through which to view the holism of change leadership. The implications arising from this study are fourfold: leadership narratives open windows to natural and vicarious meaning making, personal biography is of central rather than peripheral importance, emotional and micropolitical literacy crucial, and professional mentoring a potentially powerful catalyst in building practice wisdom.

text: Context counts : leading educational reform in New Zealand secondary schools Educational leadership and organisational literature is replete with syntheses of effective leader behaviours, change sequences and reform models, yet few studies explore the nuanced manner in which individual leaders make sense of and respond to the dynamic influences shaping their thinking and practice over time. In posing the question, how do principals experience leadership during periods of intentional educational change, this study gains insight into the lived experience of five New Zealand secondary school principals as they lead school wide implementation of Phase 5 Te Kotahitanga, a reform initiative designed to reduce disparities in the educational achievement of indigenous Māori students through the introduction of a culturally responsive pedagogy of relations. The case narratives arising from a three year dialogue with participants examine the genesis of each principal’s commitment to equity in educational access, opportunity and outcome; their evolving thinking and practice; and the manner in which people and structures within each school field enable and constrain their leadership endeavours. Findings demonstrate that leading counter-hegemonic change is a situated, complex and demanding undertaking, the intensity of which eludes much of the leadership and change literature. Hermeneutic reading of these rich qualitative accounts of lived experience suggests that, far from being detached observers, leaders both embody and are embedded in context. This exposes the shortcomings of literature that dichotomises the two and makes Bourdieu’s lens on practice as a temporal, embodied, discursive and social activity an important heuristic through which to view the holism of change leadership. The implications arising from this study are fourfold: leadership narratives open windows to natural and vicarious meaning making, personal biography is of central rather than peripheral importance, emotional and micropolitical literacy crucial, and professional mentoring a potentially powerful catalyst in building practice wisdom.

year: 2019