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Spinal motor control can provide substantial insight for the causes of spinal musculoskeletal disorders. Its dynamic characteristics however, have not been fully investigated. The objective of this study is to explore the dynamic characteristics of spinal motor control via the fractional Brownian motion mathematical technique. Spinal curvatures and repositioning errors of different spinal regions in 64 children age 11- or 15-years old during upright stance were measured and compared for the effects of age and gender. With the application of the fractional Brownian motion analytical technique to the changes of spinal curvatures, distinct persistent movement behaviors could be determined, which could be interpreted physiologically as open-loop behaviors. Moreover, it was found that the spinal motor control of 15-year-old children was better than that of 11-year-old children with smaller repositioning error and less curvature variability as well as shorter response time and smaller curvature deformation. [ABSTRACT FROM AUTHOR]

Abstract Background Tienchi (Panax notoginseng) has been used in conservative treatments for back pain as a major ingredient of many herbal medicines. This study aims to investigate the effects of a herbal medicine containing tienchi on compressed intervertebral discs in rats. Methods Using an in vivo rat tail model, intervertebral disc compression was simulated in the caudal 8–9 discs of 25 rats by continuous static compression (11 N) for 2 weeks. An herbal medicine plaster (in which the major ingredient was tienchi) was externally applied to the compressed disc (n=9) for three weeks, and held in place by an adhesive bandage, in animals in the Chinese Medicine (CM) group. The effect of the bandage was evaluated in a separate placebo group (n=9), while no intervention with unrestricted motion was provided to rats in an additional control group (n=7). Disc structural properties were quantified by in vivo disc height measurement and in vitro morphological analysis. Results Disc height decreased after the application of compression (P < 0.001). The disc height decreased continuously in the control (P = 0.006) and placebo (P = 0.003) groups, but was maintained in the CM group (P = 0.494). No obvious differences in disc morphology were observed among the three groups (P = 0.896). Conclusion The tienchi-containing herbal plaster had no significant effect on the morphology of compressed discs, but maintained disc height in rats.

The effects of sport imagery training and imagery ability on badminton service return performance (hitting speed, hitting accuracy, and swing posture) were investigated in a school-based physical education (PE) setting. Two groups of 30 and 29 Grade-11 schoolboys, respectively, were trained using conventional and imagery teaching methods in four 70-min weekly PE lessons. The students' imagery ability was classified (as low or high) using a questionnaire. Three-way mixed analysis of variance was employed to determine the effects of teaching method, imagery ability, and performance test (before and after the PE lessons) on the performance. This study discovered significant effects of imagery ability on hitting speed; performance test and the teaching method-performance test interaction on hitting accuracy; and imagery ability and performance test on swing posture. In conclusion, badminton imagery training was discovered to positively exert different effects on students with differing imagery ability in a school-based PE setting. [ABSTRACT FROM AUTHOR]

The Test of Gross Motor Development 2 (TGMD-2) is currently the standard approach for assessing fundamental movement skills (FMS), including locomotor and object control skills. However, its extensive application is restricted by its low efficiency and requirement of expert training for large-scale evaluations. This study evaluated the accuracy of a newly-developed video-based classification system (VCS) with a marker-less sensor to assess children's locomotor skills. A total of 203 typically-developing children aged three to eight years executed six locomotor skills, following the TGMD-2 guidelines. A Kinect v2 sensor was used to capture their activities, and videos were recorded for further evaluation by a trained rater. A series of computational-kinematic-based algorithms was developed for instant performance rating. The VCS exhibited moderate-to-very good levels of agreement with the rater, ranging from 66.1% to 87.5%, for each skill, and 72.4% for descriptive ratings. Paired t-test revealed that there were no significant differences, but significant positive correlation, between the standard scores determined by the two approaches. Tukey mean difference plot suggested there was no bias, with a mean difference (SD) of -0.16 (1.8) and respective 95% confidence interval of 3.5. The kappa agreement for the descriptive ratings between the two approaches was found to be moderate (k = 0.54, p < 0.01). Overall, the results suggest the VCS could potentially be an alternative to the conventional TGMD-2 assessment approach for assessing children's locomotor skills without the necessity of the presence of an experienced rater for the administration. [ABSTRACT FROM AUTHOR]

Objective: The efficacy of two optimization-driven biomechanical modeling approaches has been compared with an electromyography-assisted optimization (EMGAO) approach to predict lumbar spine loading while walking with backpack loads.Background: The EMGAO approach adopts more variables in the optimization process and is complex in data collection and processing, whereas optimization-driven approaches are simple and include the fewest possible variables. However, few studies have been conducted on the efficacy of using the optimization-driven approach to predict lumbar spine loading while walking with backpack loads.Method: Anthropometric information of 10 healthy male adults as well as their kinematic, kinetic, and electromyographic data acquired while they walked with various backpack loads (no-load, 5%, 10%, 15%, and 20% of body weight) served as inputs into the model for predicting lumbosacral joint compression forces. The efficacy of two optimization-driven models, namely double linear optimization with constraints on muscle intensity and single linear optimization without any constraints, was investigated by comparing the resulting force profile with that provided by a current EMGAO approach.Results: The double and single linear optimization approaches predicted mean deviations in peak force of -5.1%, and -19.2% as well as root-mean-square differences in force profile of 16.2%, and 25.4%, respectively.Conclusion: The double linear optimization approach was a relatively comparable estimator to the EMGAO approach in terms of its consistency, slight bias, and efficiency for predicting peak lumbosacral joint compression forces.Application: The double linear optimization approach is a useful biomechanical model for estimating peak lumbar compression forces while walking with backpack loads. [ABSTRACT FROM AUTHOR]

An attempt made to study the effect of fatigue on the muscular and postural response to sudden release of different stoop lifting loads is presented. The duration of co-contraction appears to increase while fatigue of the trunk extensors does not appear to increase either the risk of fall or stumble or the incidence of co-contraction following sudden release of stoop lifting tasks.

Objective: To investigate gender differences in energy expenditure during walking with backpack and double-pack loads. Background: Studies have reported that energy expenditure during walking with double-pack loads is lower compared with backpack carriage. However, the effect of gender on energy expenditure while walking with these two load distribution systems has not been investigated. Method: Thirty healthy young adults (15 female and 15 male participants) walked on a treadmill with backpack and double-pack loads weighing 30% of their body weight at a speed of 0.89 m/s for 10 min. The energy expenditure in terms of oxygen consumption (VO2) and respiratory exchange ratio (RER) were continuously monitored using a portable gas analyzer throughout each walking exercise. A mixed-design analysis of variance model was adopted to test the effects of gender, pack, and time on VO2 and RER. Results: No time effect was observed on VO2. However, significant gender, pack, and interaction effects were observed. The lowest VO2 was found in female participants under double-pack carriage. No significant gender or pack differences existed in RER. However, RER significantly and incrementally increased in time from the 4th through 6th, 8th, and 10th min. Conclusion: This study revealed that heavy double-pack load carriage for healthy young female participants had significantly lower energy expenditure (normalized by the entire system weight, i.e., the participant's weight plus the weight of the pack) than that of the male participants in a 10-min walking exercise. Application: The findings of this study indicated that healthy young female participants carried a heavy double-pack with less energy cost (normalized by the entire system weight, i.e., the participant's weight plus the weight of the pack) compared with their male counterparts during a 10-min walking exercise. [ABSTRACT FROM AUTHOR]

Background: Usual guidelines recommend symmetric load carriage over asymmetric load carriage. Whether this recommendation is valid for subjects with asymmetric body alignment, such as those with scoliosis, remains unclear. Scoliosis is both a subject-dependent and time-variant condition. Interventions are generally employed to prevent the abnormal spinal curvature from progressing.Objectives: To investigate the effects of an asymmetric load carriage on lateral spinal deformity in participant with scoliosis.Study Design: Repeated measure and single-case experimental designs Methods: Photogrammetry was employed to measure the scoliotic curvature changes in thoracic and lumbar regions without a load (0%) and with a single-strap cross-chest bag loaded at 2.5%, 5%, 7.5%, 10% and 12.5% of body weight. Statistical tests and programming models were adopted to determine the loading conditions (placement and weight of the bag) with optimal and minimal corrections of the affected and unaffected scoliotic spinal regions, respectively.Results: Significant short-term postural correction of scoliosis was achieved through applying an asymmetric load on the ipsilateral shoulder relative to the apex location of the major scoliotic curve.Conclusion: A subject-specific optimal loading configuration was determined using a programming model. The results suggest that the application of a properly controlled asymmetric load carriage might be possible for reducing scoliotic spinal curvature. Further study of the long-term effects of subject-specific optimal asymmetric load carriage on scoliotic spinal curvatures is warranted. Clinical relevance Short-term reduction of scoliotic spinal curvatures under asymmetric load carriage was demonstrated. Thoracic curvatures could be reduced when asymmetric loading was applied on the ipsilateral shoulder relative to the scoliotic apex. Multiobjective programming was applied to determine the optimal weight of asymmetric load for participant with scoliosis. [ABSTRACT FROM AUTHOR]

This study investigated the effects of carrying a backpack while walking. Critical changes featuring the disproportionality of increases in trunk muscle activation and lumbar joint loading between light and heavy backpack carriage weight may reveal the load-bearing strategy (LBS) of the lumbar spine. This was investigated using an integrated system equipped with a motion analysis, a force platform and a wireless surface electromyography (EMG) system to measure the trunk muscle EMG amplitudes and lumbar joint component forces. A predictive goal programming model was developed to determine the most critical changes in trunk muscle activation and lumbar joint loading. Results suggested that lightweight backpack carriage at approximately 3% of body weight (BW) might reduce the peak lumbosacral compression force by 3% during walking compared with no load condition. The most critical changes in both trunk muscle activation and lumbosacral joint loading were found at a backpack load of 10% of BW. Practitioner Summary: This study investigated the effects of backpack load on the LBS of lumbar spine while walking. A backpack load of 3% of BW might reduce the peak lumbosacral compression force by 3 and 10% of BW induced the most critical changes in LBS of lumbar spine. [ABSTRACT FROM PUBLISHER]

The article presents a study which examines the structural aspects of degenerated invertebral disc after using various traction protocols. The study involved forty-seven mature rats which were subjected to continuous static compression of 11 N at the rat caudal 8-9 disc for 2 weeks. Researchers found a significant decline in disc height with degenerative morphologic changes after being subjected to static compression. They concluded that traction of relative low magnitude was beneficial for the maintenance of disc height.

The objective of this study was to assess the effects of acupuncture applied at Hegu (LI 4) points and Neiguan (PC6) points on heart rate variability (HRV) in normal subjects under fatigue and non-fatigue states using power spectral analysis. Twenty-nine normal male subjects were randomly divided into three groups. Subjects in Group A and Group B performed a simulated driving task for 3 h and acupuncture needles were then inserted perpendicularly into the LI 4 points in the middle of the dorsal thenar muscle and PC 6 points situated between the tendons of the palmaris longus and carpi radialis muscles for 15 min for Group A but inserted subcutaneously to the acupuncture points for Group B as a control. Acupuncture needles were directly inserted perpendicularly into the LI 4 points and PC 6 points for 15 min for Group C. Stimulations of the acupuncture points induced a significant decrease in heart rate (HR), HRV total power (TP), low frequency (LF) power and ratio of low frequency to high frequency (LF/HF), and a significant increase in the HF power in normalized units (NU) during the post stimulation period in fatigue state ( P<0.05). Stimulation of acupuncture points resulted in a significant increase both in the LF power and HF power in absolute units (AU) ( P<0.05) but no significant change in NU was found during the post stimulation period in non-fatigue state. It was concluded that the modulating effect of acupuncture on heart rate variability not only depended on the points of stimulation such as acupuncture or non-acupuncture points but also on the functional state of the subject, namely whether the subjects are in a state of fatigue or not. [ABSTRACT FROM AUTHOR]

Abstract--Residual limb recovery after a transtibial amputation depends largely on close monitoring of the weight-bearing activities during the early postoperative stage. Although a biofeedback device, in particular audio biofeedback, was recommended to be used, no quantitative studies regarding its effectiveness in monitoring the weight-bearing activity of a person with amputation were available. In this study, six persons with transtibial amputation were asked to replicate a prescribed amount of weight bearing using a bathroom scale method during their early postoperative ambulatory training. Their weight-bearing characteristics with and without using audio biofeedback were continuously monitored using a load monitoring device and compared with the prescribed load. The results showed that the residual limb would be overloaded using the conventional bathroom scale method during early postoperative ambulatory training if no audio biofeedback was provided. It was demonstrated that audio biofeedback was useful in preventing the residual limb from being overloaded beyond the prescribed load particularly when the prescribed load was low. [ABSTRACT FROM AUTHOR]

During the half time of intermittent team sports, substantial physiological changes relating to acid--base balance and glycemic response affect the second-half performance. Refuel and rehydrate strategy is therefore necessary to be investigated. This field experiment assessed the acute effect of a brief mindfulness-based intervention (MBI) coupled with fluid intake on players' cognitive function in a simulated soccer game. In a single-blinded, randomized, cross-over experiment, 14 male players received three treatments [Control: noncarbohydrate solution + traveling introduction audio; CHO: Carbohydrate (CHO)--electrolyte solution + traveling introduction audio; and CHO-M: CHO--electrolyte solution + MBI] during a simulated half-time break of a soccer game. Participants' mindfulness level, blood glucose and lactate, rating of perceived exertion, and cognitive function performance assessed by the Stroop effect task (ST), Corsi block-tapping test (CBT), and rapid visual information processing task (RVIPT) were immediately measured before, during, and after the trial. Repeated measure ANOVA was used for statistical analysis. The results revealed that: (1) in ST, the CHO&lowbar;M group performed better than the Control group and marginally better than the CHO group; (2) in CBT, both the Control group and CHO-M group responded faster in the posttest than in the pretest; however, the performance of the CHO group remained the same; (3) the CHO group spent less time on missing numbers in post RVIPT compared with the other two groups. In conclusion, findings of this study provided a preliminary evidence of the positive effect of MBI coupled with CHO intake on athletes' cognitive function, with both positive and negative effect of CHO ingestion. [ABSTRACT FROM AUTHOR]

Distance running related injuries are common, and many ailments have been associated with faulty posture. Conventional measurement of running kinematics requires sophisticated motion capture system in laboratory. In this study, we developed a wearable solution to accurately predict lower limb running kinematics using a single inertial measurement unit placed on the left lower leg. The running data collected from participants was used to train a model using long short-term memory (LSTM) neural networks with an inter-subject approach that predicted lower limb kinematics with an average accuracy of 80.2%, 85.8%, and 69.4% for sagittal hip, knee and ankle joint angles respectively for the ipsilateral limb. A comparable accuracy range was observed for the contralateral limb. The average RMSE (root mean squared error) of sagittal hip, knee and ankle were 8.76°, 13.13°, and 9.67° respectively for the ipsilateral limb. Analysis of contralateral limb kinematics was performed. The model established in this study can be used as a monitoring device to track essential running kinematics in natural running environments. Besides, the wearable solution can be an integral part of a real-time gait retraining biofeedback system for injury prevention and rehabilitation.

Background: Active exercise is the only proven effective intervention for knee osteoarthritis (OA). The addition of manual therapy has shown to improve outcome of exercises. Passive mobilization with submaximal bilateral passive ankle dorsiflexion was examined in a double-blinded randomized controlled clinical trial. A passive ankle dorsiflexion apparatus was used to standardize the frequency, range of motion, and duration parameters., Objectives: The purpose of the study was to determine whether a simple standardised mobilization technique could be incorporated as a safe and unsupervised conservative treatment for knee OA., Methods: In total, 73 participants were randomly assigned to the experimental (n= 37) or control group (n= 36). All participants performed active exercises and received six sessions of 10-minute dorsiflexion intervention, either real or sham, for two weeks. Pre- and post-experimental assessments for the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), visual analog scale (VAS) for pain, and range of motion of the knee were conducted., Results: Results were analyzed using two-way repeated measures analysis of variance and Independent-Samples Mann-Whitney U Test. The mean score of WOMAC for the experimental and control groups changed from 31.84 to 18.19 and 34.74 to 21.06, respectively, after the intervention. The VAS also showed significant improvements. Significant improvements were observed in WOMAC in both groups after the intervention; however, differences between the groups were not statistically significant., Conclusions: Exercise with either 30∘ or 5∘ of passive dorsiflexion yielded favorable clinical effects. Although submaximal bilateral ankle dorsiflexion was proven to be safe for elderly participants with osteoarthritis of the knee, whether it provided extra benefits to exercises alone was unclear. Further research is required to determine the effectiveness of dorsiflexion and optimal range of mobilization.

During the half time of intermittent team sports, substantial physiological changes relating to acid-base balance and glycemic response affect the second-half performance. Refuel and rehydrate strategy is therefore necessary to be investigated. This field experiment assessed the acute effect of a brief mindfulness-based intervention (MBI) coupled with fluid intake on players' cognitive function in a simulated soccer game. In a single-blinded, randomized, cross-over experiment, 14 male players received three treatments [Control: noncarbohydrate solution + traveling introduction audio; CHO: Carbohydrate (CHO)-electrolyte solution + traveling introduction audio; and CHO-M: CHO-electrolyte solution + MBI] during a simulated half-time break of a soccer game. Participants' mindfulness level, blood glucose and lactate, rating of perceived exertion, and cognitive function performance assessed by the Stroop effect task (ST), Corsi block-tapping test (CBT), and rapid visual information processing task (RVIPT) were immediately measured before, during, and after the trial. Repeated measure ANOVA was used for statistical analysis. The results revealed that: (1) in ST, the CHO&#95;M group performed better than the Control group and marginally better than the CHO group; (2) in CBT, both the Control group and CHO-M group responded faster in the posttest than in the pretest; however, the performance of the CHO group remained the same; (3) the CHO group spent less time on missing numbers in post RVIPT compared with the other two groups. In conclusion, findings of this study provided a preliminary evidence of the positive effect of MBI coupled with CHO intake on athletes' cognitive function, with both positive and negative effect of CHO ingestion., (© Journal of Sports Science and Medicine.)

The stiffness matrix is a useful way to describe the mechanical behaviour of the functional spinal unit, which is defined as the superior and inferior vertebrae, capsules and ligaments. This usefulness is extended by means of the concept of the "balance point". The balance point is the load application point where the coupling coefficients of the stiffness matrix are minimized. Theoretical considerations are used to demonstrate that the stiffness matrix varies with load point location and thus a single stiffness matrix does not fully characterize the motion segment as well as to derive the stiffness matrix at any one specified point from the stiffness matrix at some other specified point. Special characteristics of the stiffness matrix obtained by loading through the "balance point" were shown. Some possible advantages derived from mechanical testing using the "balance point" concept are discussed. This study validates an improved stiffness matrix model that enhances the understanding of pathological changes by setting the gold standard of the behaviour of a normal functional spinal unit., (Copyright © 2019 IPEM. Published by Elsevier Ltd. All rights reserved.)

Electromyography-assisted optimization (EMGAO) approach is widely used to predict lumbar joint loads under various dynamic and static conditions. However, such approach uses numerous anthropometric, kinematic, kinetic, and electromyographic data in the computation process, and thus makes data collection and processing complicated. This study developed an electromyography-based support vector machine (EMGB&#95;SVM) approach for predicting lumbar spine load during walking with backpack loads. The EMGB&#95;SVM is simple and uses merely the electromyographic data. Anthropometric information of 10 healthy male adults as well as their kinematic, kinetic, and electromyographic data acquired during walking exercises with no-load and with various backpack loads (5%, 10%, 15%, and 20% of their body weight) were used as the inputs of a biomechanical model, which was then used for predicting the lumbosacral joint compression force. The efficacy of the EMGB&#95;SVM was investigated by comparing the force profiles obtained using this model with those obtained using the current EMGAO approach. On average, the EMGB&#95;SVM obtained deviations in the peak and minimum forces of -3.3% and 5.1%, respectively, and a root mean square difference in the force profile of 7.5%. The EMGB&#95;SVM is a comparable estimator in terms of its slight bias, favourable consistency, and efficiency at predicting the lumbosacral joint compression force., (Copyright © 2019. Published by Elsevier Ltd.)

Background: The fluctuations within stride time series (i.e., stride time variability and complexity) during running exhibit long-range correlation. Detecting the breakdown of the long-range correlation was proposed for monitoring the occurrence of running-related injuries during running. However, the stride time fluctuations were only measured from the unilateral side. In addition, the reliability of the stride time fluctuations of within-subject repeated measures remains largely unknown, particularly during exhaustive running., Purposes: This study investigated between-side and between-day reliabilities of the stride time variability and complexity of right and left sides during an exhaustive running., Methods: The stride time variability and complexity of bilateral sides were obtained while 24 healthy participants performed a 31-minute treadmill running at their individual anaerobic threshold speed. Seven of the 24 participants performed the treadmill running test twice at two different days 5-7 days apart. Limits of agreement (LoA) and intraclass correlation coefficient (ICC) were respectively used to assess the absolute and relative between-side and between-day reliabilities., Results: The stride time variability and complexity of right and left sides were highly symmetrical (LoA: (-0.500%, 0.459%) and (-0.052, 0.051), respectively; ICC: 0.94 (0.87, 0.97) and 0.98 (0.95, 0.99), respectively). The overall stride time variability and complexity revealed good between-day reliability (LoA: (-1.044%, 0.724%) and (-0.067, 0.115), respectively; ICC: 0.78 (0.45, 0.92) and 0.81 (0.48, 0.93), respectively). However, the segmented stride time complexity showed poor between-day reliability (ICCs<0.40)., Conclusion: The findings demonstrated that the stride time series showed equivalent fluctuations between right and left sides and good between-day reliability in fluctuations during exhaustive running. Given the poor between-day reliability in the segmented stride time series, stride time series during exhaustive running could be collected from either right or left side and should be processed as an overall in the future., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Walking with backpack loads induces additional mechanical stress on the spine and has been identified as a risk factor of lower-back pain. This study evaluated the effects of walking with backpack loads on the lumbosacral joint compression force profile in both the magnitude and time domains. Ten male adults geared with anatomical markers and trunk surface electromyographic sensors walked along a walkway embedded with three force plates with no load and various backpack loads (5%, 10%, 15%, and 20% body weight). Lower-body movements, ground reaction forces, and trunk muscle activations were measured using a synchronized motion analysis, force plate, and surface electromyography system. The force profiles of identified gait cycles were predicted using an integrated inverse dynamic and electromyography-assisted optimization model and evaluated statistically. The results showed that as backpack load increased, the 10th, 50th, and 90th percentiles of force profiles escalated disproportionately. However, no significant changes were observed in the timing of the two peak force incidences. Such changes in the compression force might be an indication of the combined effects of the increase in both gravitational and mass moment of inertia of the system (body plus pack loads) when walking with a backpack. Pearson correlation coefficients of the force profiles between the five loading conditions were greater than 0.94. Strong associations between the force profiles at different backpack loads were confirmed., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Background: Motor control, related to running performance and running related injuries, is affected by progression of fatigue during a prolonged run. Distance runners are usually recommended to train at or slightly above anaerobic threshold (AT) speed for improving performance. However, running at AT speed may result in accelerated fatigue. It is not clear how one adapts running gait pattern during a prolonged run at AT speed and if there are differences between runners with different training experience., Purposes: To compare characteristics of stride-to-stride variability and complexity during a prolonged run at AT speed between novice runners (NR) and experienced runners (ER)., Methods: Both NR (n = 17) and ER (n = 17) performed a treadmill run for 31 min at his/her AT speed. Stride interval dynamics was obtained throughout the run with the middle 30 min equally divided into six time intervals (denoted as T1, T2, T3, T4, T5 and T6). Mean, coefficient of variation (CV) and scaling exponent alpha of stride intervals were calculated for each interval of each group., Results: This study revealed mean stride interval significantly increased with running time in a non-linear trend (p<0.001). The stride interval variability (CV) maintained relatively constant for NR (p = 0.22) and changed nonlinearly for ER (p = 0.023) throughout the run. Alpha was significantly different between groups at T2, T5 and T6, and nonlinearly changed with running time for both groups with slight differences., Significance: These findings provided insights into how the motor control system adapts to progression of fatigue and evidences that long-term training enhances motor control. Although both ER and NR could regulate gait complexity to maintain AT speed throughout the prolonged run, ER also regulated stride interval variability to achieve the goal., (Copyright © 2018 Elsevier B.V. All rights reserved.)