Objective To classify the foot types of young Chinese males,extract characteristic indicators of foot types,and construct a standard foot type database.Methods Foot type data from 1 483 healthy young male individuals were collected.Spectral clustering algorithm was utilized to categorize foot types,and a deep neural network(DNN)was employed for training the classification model.Layer-wise relevance propagation(LRP)and the correlation coefficient method were combined to extract foot type features,and the differences in various foot type characteristics were compared.Results Spectral clustering yielded 4 distinct foot type categories.Foot type 1 was characterized by a high-arched foot with a prominent big toe,inwardly rotated 5th toe,and a high heel with a wide foot;foot type 2 was characterized by a narrow foot with hallux valgus;foot type 3 was characterized by a low-arched foot with hallux valgus;foot type 4 was characterized by a high-arched foot with a prominent big toe.By integrating interpretable neural networks and the correlation coefficient method,nine indicators were extracted from 27 foot type indicators,including the heel to the sole length,hallux height,navicular bone height,lateral malleolus height,hallux valgus angle,5th toe angle,dorsal foot circumference,heel angle,and longitudinal arch angle.The classification model constructed with these extracted indicators achieved an overall discrimination accuracy rate of 93.67％.Conclusions Chinese young males can be classified into four typical foot types.By examining the rearfoot,midfoot,and forefoot regions,nine key foot morphology parameters,including length,height,circumference,and angle,can be extracted.These parameters provide both theoretical and empirical support for establishing normative data on foot morphology for Chinese young males and for advancing biomechanical researches on the foot and ankle.

Objective To explore the effect of cognitive-motor dual tasks with different cognitive loads(none,simple and difficult)on activation of prefrontal cortex and static posture control in young man.Methods From June to July,2024,27 healthy male college students were recruited in Hebei Normal University.Static postural control parameters(C90 area),lower limb electromyography data(muscle energy proportion)and pre-frontal cortex hemodynamic signals of subjects under single task without cognitive load,dual-task with simple cognitive load,and dual-task with difficult cognitive load were collected using a balanced testing and training system,a wireless surface electromyography device,and functional near-infrared spectroscopy technology.Results The C90 areas of dual-tasks with simple and difficult cognitive load were smaller than that of the single task without cognitive load(P<0.05).The proportion of β band energy in the medial and lateral gastrocnemius mus-cles in the dual-task with simple cognitive load was greater than that in the single task without cognitive load(P<0.05),while the proportion of piper band energy in the lateral gastrocnemius muscle and tibialis anterior muscle was less(P<0.05).During dual-task with difficult cognitive load,the activation levels of bilateral ventro-lateral prefrontal cortex and right dorsolateral prefrontal cortex were higher than those in the single task without cognitive load(P<0.05).Conclusion Dual tasks with appopriate cognitive loads are effective on postural stability in young man.Simple cognitive load promote posture maintenance through optimizing the neuromuscular control of the lower limb muscle groups,while difficult cognitive load through activating the right prefrontal cortex involved in working memory and executive control,involving the neurocognitive compensatory.

Objective To explore the correlation between single-leg standing posture control and ankle plantar flexor muscle stability,so as to provide a new theoretical basis for improving the ability of human posture control.Methods A total of 20 healthy male college students were randomly selected as the experimental subjects.The iBalance tester and training system was used to test the trajectory data of the center of pressure(COP)of the foot standing on one leg.The CON-TREX MJ multi-joint isokinetic test and training system was used to test the moment amplitude data during the contraction of ankle plantar flexor muscles.Univariate repeated measures variance analysis was used to analyze the standard deviation data of ankle plantar flexor moment amplitude between groups.The Pearson correlation coefficient was used to study the correlation.Results The greater the intensity of the muscle stabilization task performed by the ankle plantar flexor muscle,the greater the standard deviation of the moment amplitude.The C90 area was positively correlated with the coefficient of variation(CV)of the 10％maximum voluntary contraction(MVC)moment of ankleplantar flexor muscle(r=0.761,P＜0.05)during single-leg standing without interference.The C90 area was positively correlated with the CV(r=0.632,P＜0.05)of the 30％MVC moment of ankle plantar flexor muscle during single-leg standing.When the proprioception was interfered during single-leg standing,the C90 area was positively correlated with the CV(r=0.583,P＜0.05)of the 20％MVC moment amplitude of ankleplantar flexor muscle.Conclusions With the increasing difficulty of muscle strength stabilization performed by the ankle plantar flexor muscles,muscle stability decreases.There is a positive correlation between ankle plantar flexor strength stability and single-leg standing posture control.Compared with the case without interference,under visual and proprioceptive interference,an additional information input is reduced or disturbed,and it is more difficult to maintain body balance,and the ankle plantar flexor muscle needs a higher muscle stability in the force mode to participate in the posture control of the human body during single-leg standing.

Objective To explore the correlation between single-leg standing posture control and ankle plantar flexor muscle stability,so as to provide a new theoretical basis for improving the ability of human posture control.Methods A total of 20 healthy male college students were randomly selected as the experimental subjects.The iBalance tester and training system was used to test the trajectory data of the center of pressure(COP)of the foot standing on one leg.The CON-TREX MJ multi-joint isokinetic test and training system was used to test the moment amplitude data during the contraction of ankle plantar flexor muscles.Univariate repeated measures variance analysis was used to analyze the standard deviation data of ankle plantar flexor moment amplitude between groups.The Pearson correlation coefficient was used to study the correlation.Results The greater the intensity of the muscle stabilization task performed by the ankle plantar flexor muscle,the greater the standard deviation of the moment amplitude.The C90 area was positively correlated with the coefficient of variation(CV)of the 10％maximum voluntary contraction(MVC)moment of ankleplantar flexor muscle(r=0.761,P＜0.05)during single-leg standing without interference.The C90 area was positively correlated with the CV(r=0.632,P＜0.05)of the 30％MVC moment of ankle plantar flexor muscle during single-leg standing.When the proprioception was interfered during single-leg standing,the C90 area was positively correlated with the CV(r=0.583,P＜0.05)of the 20％MVC moment amplitude of ankleplantar flexor muscle.Conclusions With the increasing difficulty of muscle strength stabilization performed by the ankle plantar flexor muscles,muscle stability decreases.There is a positive correlation between ankle plantar flexor strength stability and single-leg standing posture control.Compared with the case without interference,under visual and proprioceptive interference,an additional information input is reduced or disturbed,and it is more difficult to maintain body balance,and the ankle plantar flexor muscle needs a higher muscle stability in the force mode to participate in the posture control of the human body during single-leg standing.

Objective To explore the effect of cognitive-motor dual tasks with different cognitive loads(none,simple and difficult)on activation of prefrontal cortex and static posture control in young man.Methods From June to July,2024,27 healthy male college students were recruited in Hebei Normal University.Static postural control parameters(C90 area),lower limb electromyography data(muscle energy proportion)and pre-frontal cortex hemodynamic signals of subjects under single task without cognitive load,dual-task with simple cognitive load,and dual-task with difficult cognitive load were collected using a balanced testing and training system,a wireless surface electromyography device,and functional near-infrared spectroscopy technology.Results The C90 areas of dual-tasks with simple and difficult cognitive load were smaller than that of the single task without cognitive load(P<0.05).The proportion of β band energy in the medial and lateral gastrocnemius mus-cles in the dual-task with simple cognitive load was greater than that in the single task without cognitive load(P<0.05),while the proportion of piper band energy in the lateral gastrocnemius muscle and tibialis anterior muscle was less(P<0.05).During dual-task with difficult cognitive load,the activation levels of bilateral ventro-lateral prefrontal cortex and right dorsolateral prefrontal cortex were higher than those in the single task without cognitive load(P<0.05).Conclusion Dual tasks with appopriate cognitive loads are effective on postural stability in young man.Simple cognitive load promote posture maintenance through optimizing the neuromuscular control of the lower limb muscle groups,while difficult cognitive load through activating the right prefrontal cortex involved in working memory and executive control,involving the neurocognitive compensatory.

Objective To classify the foot types of young Chinese males,extract characteristic indicators of foot types,and construct a standard foot type database.Methods Foot type data from 1 483 healthy young male individuals were collected.Spectral clustering algorithm was utilized to categorize foot types,and a deep neural network(DNN)was employed for training the classification model.Layer-wise relevance propagation(LRP)and the correlation coefficient method were combined to extract foot type features,and the differences in various foot type characteristics were compared.Results Spectral clustering yielded 4 distinct foot type categories.Foot type 1 was characterized by a high-arched foot with a prominent big toe,inwardly rotated 5th toe,and a high heel with a wide foot;foot type 2 was characterized by a narrow foot with hallux valgus;foot type 3 was characterized by a low-arched foot with hallux valgus;foot type 4 was characterized by a high-arched foot with a prominent big toe.By integrating interpretable neural networks and the correlation coefficient method,nine indicators were extracted from 27 foot type indicators,including the heel to the sole length,hallux height,navicular bone height,lateral malleolus height,hallux valgus angle,5th toe angle,dorsal foot circumference,heel angle,and longitudinal arch angle.The classification model constructed with these extracted indicators achieved an overall discrimination accuracy rate of 93.67％.Conclusions Chinese young males can be classified into four typical foot types.By examining the rearfoot,midfoot,and forefoot regions,nine key foot morphology parameters,including length,height,circumference,and angle,can be extracted.These parameters provide both theoretical and empirical support for establishing normative data on foot morphology for Chinese young males and for advancing biomechanical researches on the foot and ankle.

Objective: To investigate the correlation between magnetic resonance imaging-based vertebral bone quality (VBQ) score and screw loosening after dynamic pedicle screw fixation with polyetheretherketone (PEEK) rods, and evaluate its predictive value. Methods: A retrospective analysis was conducted on the patients who underwent dynamic pedicle screw fixation with PEEK rods from March 2017 to June 2022. Data on age, sex, body mass index, hypertension, diabetes, hyperlipidemia history, long-term smoking, alcohol consumption, VBQ score, L1–4 average Hounsfield unit (HU) value, surgical fixation length, and the lowest instrumented vertebra were collected. Logistic regression analysis was employed to assess the relationship between VBQ score and pedicle screw loosening (PSL). Results: A total of 24 patients experienced PSL after surgery (20.5%). PSL group and non-PSL group showed statistical differences in age, number of fixed segments, fixation to the sacrum, L1–4 average HU value, and VBQ score (p < 0.05). The VBQ score in the PSL group was higher than that in the non-PSL group (3.56 ± 0.45 vs. 2.77 ± 0.31, p < 0.001). In logistic regression analysis, VBQ score (odds ratio, 3.425; 95% confidence interval, 1.552–8.279) were identified as independent risk factors for screw loosening. The area under the receiver operating characteristic curve for VBQ score predicting PSL was 0.819 (p < 0.05), with the optimal threshold of 3.15 (sensitivity, 83.1%; specificity, 80.5%). Conclusion The VBQ score can independently predict postoperative screw loosening in patients undergoing lumbar dynamic pedicle screw fixation with PEEK rods, and its predictive value is comparable to HU value.

Objective: To investigate the correlation between magnetic resonance imaging-based vertebral bone quality (VBQ) score and screw loosening after dynamic pedicle screw fixation with polyetheretherketone (PEEK) rods, and evaluate its predictive value. Methods: A retrospective analysis was conducted on the patients who underwent dynamic pedicle screw fixation with PEEK rods from March 2017 to June 2022. Data on age, sex, body mass index, hypertension, diabetes, hyperlipidemia history, long-term smoking, alcohol consumption, VBQ score, L1–4 average Hounsfield unit (HU) value, surgical fixation length, and the lowest instrumented vertebra were collected. Logistic regression analysis was employed to assess the relationship between VBQ score and pedicle screw loosening (PSL). Results: A total of 24 patients experienced PSL after surgery (20.5%). PSL group and non-PSL group showed statistical differences in age, number of fixed segments, fixation to the sacrum, L1–4 average HU value, and VBQ score (p < 0.05). The VBQ score in the PSL group was higher than that in the non-PSL group (3.56 ± 0.45 vs. 2.77 ± 0.31, p < 0.001). In logistic regression analysis, VBQ score (odds ratio, 3.425; 95% confidence interval, 1.552–8.279) were identified as independent risk factors for screw loosening. The area under the receiver operating characteristic curve for VBQ score predicting PSL was 0.819 (p < 0.05), with the optimal threshold of 3.15 (sensitivity, 83.1%; specificity, 80.5%). Conclusion The VBQ score can independently predict postoperative screw loosening in patients undergoing lumbar dynamic pedicle screw fixation with PEEK rods, and its predictive value is comparable to HU value.

Objective: To investigate the correlation between magnetic resonance imaging-based vertebral bone quality (VBQ) score and screw loosening after dynamic pedicle screw fixation with polyetheretherketone (PEEK) rods, and evaluate its predictive value. Methods: A retrospective analysis was conducted on the patients who underwent dynamic pedicle screw fixation with PEEK rods from March 2017 to June 2022. Data on age, sex, body mass index, hypertension, diabetes, hyperlipidemia history, long-term smoking, alcohol consumption, VBQ score, L1–4 average Hounsfield unit (HU) value, surgical fixation length, and the lowest instrumented vertebra were collected. Logistic regression analysis was employed to assess the relationship between VBQ score and pedicle screw loosening (PSL). Results: A total of 24 patients experienced PSL after surgery (20.5%). PSL group and non-PSL group showed statistical differences in age, number of fixed segments, fixation to the sacrum, L1–4 average HU value, and VBQ score (p < 0.05). The VBQ score in the PSL group was higher than that in the non-PSL group (3.56 ± 0.45 vs. 2.77 ± 0.31, p < 0.001). In logistic regression analysis, VBQ score (odds ratio, 3.425; 95% confidence interval, 1.552–8.279) were identified as independent risk factors for screw loosening. The area under the receiver operating characteristic curve for VBQ score predicting PSL was 0.819 (p < 0.05), with the optimal threshold of 3.15 (sensitivity, 83.1%; specificity, 80.5%). Conclusion The VBQ score can independently predict postoperative screw loosening in patients undergoing lumbar dynamic pedicle screw fixation with PEEK rods, and its predictive value is comparable to HU value.

Objective: To investigate the correlation between magnetic resonance imaging-based vertebral bone quality (VBQ) score and screw loosening after dynamic pedicle screw fixation with polyetheretherketone (PEEK) rods, and evaluate its predictive value. Methods: A retrospective analysis was conducted on the patients who underwent dynamic pedicle screw fixation with PEEK rods from March 2017 to June 2022. Data on age, sex, body mass index, hypertension, diabetes, hyperlipidemia history, long-term smoking, alcohol consumption, VBQ score, L1–4 average Hounsfield unit (HU) value, surgical fixation length, and the lowest instrumented vertebra were collected. Logistic regression analysis was employed to assess the relationship between VBQ score and pedicle screw loosening (PSL). Results: A total of 24 patients experienced PSL after surgery (20.5%). PSL group and non-PSL group showed statistical differences in age, number of fixed segments, fixation to the sacrum, L1–4 average HU value, and VBQ score (p < 0.05). The VBQ score in the PSL group was higher than that in the non-PSL group (3.56 ± 0.45 vs. 2.77 ± 0.31, p < 0.001). In logistic regression analysis, VBQ score (odds ratio, 3.425; 95% confidence interval, 1.552–8.279) were identified as independent risk factors for screw loosening. The area under the receiver operating characteristic curve for VBQ score predicting PSL was 0.819 (p < 0.05), with the optimal threshold of 3.15 (sensitivity, 83.1%; specificity, 80.5%). Conclusion The VBQ score can independently predict postoperative screw loosening in patients undergoing lumbar dynamic pedicle screw fixation with PEEK rods, and its predictive value is comparable to HU value.