Investigating pelvic drop gait abnormality in adolescent hip pathology patients.

BACKGROUND: Trendelenburg gait describes contralateral pelvic drop during single leg stance (SLS) with occasional lateral trunk lean compensation over the stance limb. However, quantitative research on 'uncompensated Trendelenburg' gait (pelvic drop independent of lateral trunk lean) remains sparse among populations that commonly utilize this gait pattern, such as adolescent hip pathology patients. RESEARCH QUESTION: How prevalent is uncompensated Trendelenburg among various adolescent hip pathologies and how is it related to hip load, hip abduction strength, and self-reported hip pain? METHODS: Gait, strength, and pain data were collected among 152 pre-operative patients clinically diagnosed with acetabular hip dysplasia, femoroacetabular impingement, Legg-Calvé-Perthes, or slipped capital femoral epiphysis (SCFE). Patients with ≥ 5.4° of dynamic pelvic drop in SLS were divided into a 'pelvic drop' group and screened to exclude those with excessive ipsilateral trunk lean. They were then compared to the 'stable pelvis' patients using a Mann-Whitney test. RESULTS: Dysplasia patients represented the highest proportion of the pelvic drop group (46%). The pelvic drop group showed a significant increase in self-reported hip pain (p = 0.011), maximum hip abductor moment (p = 0.002), and peak coronal power absorption at the affected hip during SLS loading response, (p < 0.001) while showing no difference in abduction strength (p = 0.381). SIGNIFICANCE: Uncompensated Trendelenburg gait may lead to increased loading of the affected hip in adolescent hip pathology patients. Disadvantageous hip biomechanics can create increased abductor muscle demand among these pathological populations, with dysplasia patients showing the highest prevalence. Maximal abduction strength did not correlate with pelvic drop. Future work should aim to identify and quantify causal factors. Increased coronal hip power absorption during weight acceptance warrants clinical attention, as there may be a detrimental, over-reliance on passive hip structures to support load among a population that that is already predisposed to hip osteoarthritis.

The role of social support in the relationship between physical activity and health-related quality of life among adults with visual impairments.

BACKGROUND: Studies support assertions that more social support may be related to higher physical activity behavior, which may, in turn, relate to higher health-related quality of life (HRQoL). However, these relationships remain unexplored, particularly among adults with visual impairments. OBJECTIVE: The purpose of this study was to examine the relationships between physical activity-specific social support, physical activity participation, and HRQoL among adults with visual impairments. METHODS: This cross-sectional study utilized an online survey methodology. Adults with visual impairments (n = 251) were recruited via three visual impairment LISTSERVs housed in the USA and completed four questionnaires. Data were analyzed using (a) a descriptive analysis, (b) one sample t-test, and (c) structural equation modeling to examine the relations among social support, physical activity, and HRQoL components. RESULTS: The participants reported relatively low weekly physical activity participation, with mean physical activity about 1362.02 ± 1231.37 MET-min/week. Compared to the mean T-scores of the general adult US population, the participants had significantly lower physical (43.56 ± 6.76, t = -15.10, p < .01) and mental components of HRQoL (38.24 ± 11.37, t = -16.39, p < .01). Structural equational modeling results show that social support positively predicted weekly physical activity participation (ß = 0.11), which, in turn, predicted physical component (ß = 0.12) but not mental component HRQoL (ß = 0.04, p > .05). CONCLUSIONS: Our participant sample reported significantly lower HRQoL than the general US populations. The findings suggest that social support can both directly and indirectly, through physical activity, influence psychological HRQoL among adults with visual impairments.

Lower extremity joint stiffness of autistic adolescents during running at dual speeds.

Running is one of the most common forms of physical activity for autistic adolescents. However, research examining their lower extremity dynamics is sparse. In particular, no information exists regarding lower extremity joint stiffness in autistic adolescents. This study compared knee and ankle joint stiffness during the absorption phase of running between autistic adolescents and non-autistic controls. Motion capture and ground reaction forces were recorded for 22 autistic adolescents and 17 non-autistic age, sex, and BMI matched peers who ran at self-selected and standardized (3.0 m/s) speeds. Group × speed knee and ankle joint stiffness, change in moment, and range of motion were compared using mixed-model ANOVAs. There were no group × speed interactions for any variable. Autistic adolescents presented with significant (12 % and 19 %) reduced knee and ankle joint stiffness, respectively. In addition, autistic adolescents had significant reduced changes in knee and ankle joint moments by 11 % and 21 %, respectively, compared to their non-autistic peers. Only knee joint stiffness and knee joint moments were sensitive to running speed, each significantly increasing with speed by 6 %. Current literature suggests joint stiffness is an important mechanism for stability and usage of the stretch shortening cycle (or elastic recoil); as such, it is possible that the reduced ankle plantar flexor and knee extensor stiffness found in autistic adolescents in this study could be indicative of reduced efficiency during running. As group differences existed across both speeds, autistic adolescents may benefit from therapeutic and/or educational interventions targeting efficient running mechanics.

Impact of shoe and cleat type on youth baseball pitching biomechanics.

Shoulder and elbow injuries among baseball pitchers of various ages and abilities continue to rise despite exhaustive efforts analysing pitch type and count; however, it has yet been determined if footwear plays a role in altering pitching mechanics and subsequently injury susceptibility. Therefore, the purpose of the study was to investigate the effect footwear might have on youth baseball pitching mechanics. Data were collected on eleven youth baseball pitchers wearing two different shoes on two different surface inclinations. A repeated measures ANOVA was utilised to determine differences between upper and lower extremity joint kinematics and kinetics (p < 0.05). Results indicate wearing moulded cleats elicited significantly greater amounts of shoulder internal rotation torque, angle and velocity as well as elbow varus torque. Turf shoes caused an increased plantarflexion joint angle in the stride leg ankle and shoulder external rotation torque, angle and velocity. The findings of this study suggest that the footwear worn by a youth baseball pitcher does alter the shoulder and elbow dynamics in the dominant throwing arm as well as the amount of ankle plantarflexion in the stride leg.

The relationship of coronal trunk motion on the hip abductor moment impulse in pre-operative hip pathology patients during walking.

BACKGROUND: Compensatory mechanisms for hip pain, pathology, and weakness include excessive trunk lean towards the stance limb, counteracting pelvic drop to maintain stability during single leg stance. Trunk lean shifts the center of mass towards the hip joint center to decrease the moment arm and reduce hip abductor demand. The purpose of this study was to evaluate whether adolescent patients with symptomatic hip pain demonstrate excessive trunk lean and the effect on the hip abductor moment impulse. METHODS: Self-selected speed walking data collected through an approved study were reviewed on pre-operative patients clinically diagnosed with a hip deformity. Instrumented motion analysis was performed to analyze trunk kinematics and the hip abductor moment impulse. FINDINGS: There was a weak, but significant correlation between hip abductor moment impulse and trunk lean. Patients diagnosed with Acetabular Dysplasia demonstrated an increased trunk lean and a decreased hip abductor moment impulse (r = - 0.311, p = 0.001). Of those who presented with excessive trunk lean, 62% of these patients had a normal hip abductor moment impulse. There was no correlation between hip abductor moment impulse and hip abductor strength. INTERPRETATION: Excessive trunk lean was not seen uniformly across adolescent patients with symptomatic hip deformities, despite pain being reported in 80% of patients. Furthermore, a majority of those that presented with excessive trunk lean did not present with a reduced moment, suggesting that although the amount of lean was greater than normal, it was not enough to significantly reduce the demand on the hip musculature.

The Influence of an Acute Bout of Whole Body Vibration on Human Postural Control Responses.

The use of vibrating platforms has become increasingly available, and popular at sports and rehabilitation institutes. Given the discrepancies in the literature regarding whole body vibration (WBV) and human reflexive responses, the purpose of this study was to examine the acute effects of WBV on postural response latencies, as well as associated electromyography measures of the lower extremities during balance perturbations. Reflexive responses during backward and forward balance perturbations were examined before, after, and 10 min after a bout of WBV. The findings suggest that following an acute bout of whole body vibration, muscle activity of the lower extremities is decreased during a reflexive response to an unexpected perturbation, and may be associated with faster reaction time.