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Objective@#To develop a simplified Rating Questionnaire of Social Ecological Risks in Adolescents and to evaluate the reliability and predictive validity of the brief questionnaire, so as to provide data and evidence support for building the evaluation system of cumulative social ecological risk exposure.@*Methods@#A large cross sectional was conducted in eight areas, including Shenzhen, Zhengzhou, Xuzhou, Nanchang, Shenyang, Taiyuan, Kunming and Chongqing, from October to December 2021. A total of 22 868 adolescents were included in the analysis. Data on healthy behaviors from 10 838 adolescents from Shenyang, Taiyuan, Kunming, Chongqing were used for item selection, based on factor analysis, validity and reliability evaluation. The data from Shenzhen, Zhengzhou, Xuzhou, Nanchang, including 12 030 adolescents, were used to define the partition values of the brief questionnaire, and evaluate the predictive validity.@*Results@#The brief questionnaire containing 25-item were developed by analyzing and choosing all items of original questionnaire, and covered seven dimensions including individual, family, school, community, policy, time and culture. The cumulative contribution rate of variance was 54.95%, the Cronbach coefficient was 0.79, and the split half coefficient was 0.70. Participants in the higher risk group had significantly higher risk of smoking ( OR =4.05, 95% CI = 2.78 -5.92), drinking ( OR =3.47, 95% CI =2.86-4.19), suicidal ideation ( OR =8.85, 95% CI =7.68-10.21), suicidal plans ( OR = 8.85, 95% CI =7.27-10.78), suicidal attempt ( OR = 8.86 , 95% CI =6.67-11.78) than individual in the lower risk group ( P < 0.05). After stratified by gender, the above positive correlations still remained significant( P <0.05).@*Conclusion@#The brief questionnaire, with good reliability and predictive validity, could be widely applicated in the further researches on social ecological risk factors.
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ObjectiveTo compare the retest reliability and discriminant validity of dynamic postural stability indices for functional ankle instability (FAI) obtained by different algorithms based on acceleration signals at different positions of human body. MethodsFrom April to June, 2021, 21 subjects with unilateral FAI and 21 subjects with normal ankle were recruited. Three inertial sensors were attached to the waist points, knee and ankle positions. The ground reaction force (GRF) and kinematics data of the subjects in multi-direction single leg landing test were collected synchronously by 3D force plate and inertial sensors. The unbounded third order polynomial (UTOP) fitting method was used to calculate the stability time, and the root mean square was used to caculate the stability index. ResultsMost of the indicators calculated based on acceleration signal correlated with that based on GRF with low coefficient (|r| = 0.116 to 0.368, P < 0.05). The stability time and stability index based on the acceleration signals of different positions of human body showed low to high retest reliability (CMC 0.30 to 0.91). For the females, among the stability time based on acceleration signal, eleven indexes achieved average to very high discriminant validity (AUC = 0.702 to 0.942, P < 0.05); eight of the stability indexes reached general level of discriminant validity (AUC = 0.717 to 0.782, P < 0.05). No algorithms achieved good discriminant effect in male subjects. ConclusionBased on the acceleration signal of waist point in single-leg landing stability test, the stability time calculated by UTOP algorithm can evaluate the dynamic postural stability of female FAI patients with high discriminant validity and medium to high retest reliability.
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ObjectiveTo compare the effects of proprioceptive neuromuscular facilitation (PNF) and whole body vibration training (WBVT) on functional ankle instability (FAI). MethodsFrom May to July, 2021, 17 male FAI undergraduates from Beijing Sport University received PNF (n = 8) and WBVT (n = 9), for six weeks. They were assessed with Y-balance test, Pro-Kin, Kistler and Motion Analysis Raptor before and after invention, to observe Y-balance score, average trajectory error, kinematics and dynamics after jump-landing of affected limb. ResultsThe main effect of training was not significant for all the Y-balance score, average trajectory error, kinematics and dynamics (F < 4.090, P > 0.05). However, the interactive effect of training and time was significant for the range of motion of ankle flexion (F = 6.232, P = 0.030), and the effect size was more for PNF; it was also significant for the time arriving peak ground reaction force (left-right) after landing (F = 10.674, P = 0.008), and the time was latter for WBVT (P < 0.05). ConclusionPNF and WBVT are similarly effective on FAI.
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Objective To build a method for calculating the optimal length of hamstring muscles in vivo, and make comparison with other indirect parameters which represent the optimal length. Methods By synchronously recording knee flexion torque and kinematic data, the musculoskeletal model of lower limbs was built to obtain hamstring strength and muscle length, and to further calculate the optimal length of hamstring muscles. Results Flexion angle at peak knee flexion torque was significantly greater than that at peak hamstring strength and their correlation coefficient was 0.741. The optimal lengths of each bi-articulated hamstring muscles were significantly greater than the corresponding muscle lengths during standing and their correlation coefficients was low. Conclusions The established estimating method for optimal length of hamstring muscles provided references for future studies on injury mechanism and risk factors. Flexion angle at peak knee flexion torque could partly represent the optimal length of hamstring. It is not suggested that hamstring muscle length during standing should be used as an approximation of hamstring optimal length.
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Objective To study the sex-specific lower extremity biomechanics of amateur runners with patellofemoral pain (PFP). Methods Fifteen male and ten female amateur runners with PFP were identified and enrolled in PFP group, twenty-five healthy amateur runners matched with the PFP group were recruited as control group. The kinematics and kinetics, surface electromyography (EMG) data from all the subjects in the running task were collected.Two-way analysis of variance was performed to determine the influence of group and sex on lower extremity biomechanics during running. Results Compared with control group, male amateur runners with PFP showed a greater peak knee flexion angle during the landing phase of running. Compared with control group, male and female amateur runners with PFP showed a greater peak hip adduction angle during the landing phase of running, while the peak hip adduction angle of female participants was significantly greater than that of male participants. Conclusions Amateur runners with PFP showed sex-specific lower extremity biomechanics in the running task, and the clinical intervention for PFP should be sex-specific.