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Background Stair climbing is a complex and demanding daily activity with increased physical loads. Therefore, analyzing stair climbing abilities is a frequently used diagnostic tool. Leg length inequalities (LLIs) are a common condition in the population, with individual consequences like lower back pain, scoliosis, and osteoarthritis. Despite its high prevalence, the necessary treatment, for mild LLIs, is still controversial. Previously, the focus was to analyze the effects of LLIs during static standing and walking. To create a holistic view on the dynamic effects of LLIs, and since climbing stairs produces a similar biomechanical imbalance as LLIs, the compensation mechanics during stair climbing are of special interest. Research question What are the biomechanical compensation mechanisms of (simulated) LLIs during ascending and descending stairs? Methods Thirty-five healthy participants were measured with the inertial measurement system MyoMotion during stair climbing with simulated LLIs of 0–3 cm. The maximum estimated lower limb joint angles of the long and short leg were analyzed with statistically repeated measurement models. Results The long leg showed significantly increased hip and knee flexion, while the short leg showed decreased hip and knee flexion, decreased dorsiflexion, and significantly increased plantarflexion. Different mechanisms were found in the case of 1 cm LLI when compared to greater LLIs. In the former, increased hip and knee flexion in the short leg accompanied by increased dorsiflexion in the long leg was observed. In the latter, the dorsiflexion of the long leg was reduced. Significance Except for the reduced dorsiflexion of the long leg (LLI >1 cm), during stair climbing compared compensation mechanisms as during walking were presented, with the long leg functionally shortened and the short leg lengthened. Although the feet were already on different levels, during stair climbing with the step-over-step technique, significant compensation mechanisms were found as a consequence of LLIs.

[Purpose] This study aimed to clarify the immediate effect of adding mirror visual feedback to lateral weight-shifting training on the standing balance control of the left unilateral spatial neglect model. [Participants and Methods] We included 64 healthy participants to create left unilateral spatial neglect models and divided them into four subgroups. Each subgroup received opposite lateral weight-shifting training with or without mirror visual feedback. We then evaluated the static and dynamic standing balance by measuring the center of pressure point alterations in the medial-lateral and anterior-posterior planes. We further evaluated the center of pressure length and bilateral load ratio. [Results] The center of pressure was significantly stable upon performing the eyes-open static standing balance test in the left weight-shifting training subgroup with mirror visual feedback. When participants performed the left dynamic standing balance test, the center of pressure moved significantly rightward and became significantly stable in the right weight-shifting training subgroup with mirror visual feedback. The left load ratio significantly decreased in the right weight-shifting training of subgroups that either did or did not receive mirror visual feedback upon performing the left dynamic standing balance test. [Conclusion] We concluded that adding mirror visual feedback to lateral weight-shifting training affected some measurements of standing balance control of the left unilateral spatial neglect model., 東京都立大学学位論文甲第1149号 副論文

[Purpose] The March Test (MT), evaluating hypomobility of the sacroiliac joint (SIJ), is often used in clinical practice to evaluate low back pain but has limited reported validity and reliability. Capturing the innominate movement at SIJ associated with the results of MT has not been examined. The purpose of this study was to determine if there was a significant difference in the motion of the innominate between a positive and a negative MT. [Participants and Methods] Sixteen healthy volunteers were assigned into two groups: positive or negative results of the MT. All participants were asked to perform three different tasks: standing on both limbs, static standing on one-limb and flexing the hip to 90 and 100 degrees, and active flexing the hip past 90 degrees. In a 3D motion analysis system, virtual vectors created by landmarks over the ilium defined innominate movement of the ilium related to the sacrum, which were compared between the groups. [Results] There was significantly limited innominate movement in the March Test positive group compared to the March Test negative group. [Conclusion] This study showed hypomobility at SIJ in the March test positive groups. Further investigation is needed for clinical applications.

Introduction: This study aimed to investigate the foot function, range of motion, plantar pressure, and plantar contact area in the distance runners with normal, pronated, highly-pronated, supinated, and highly-supinated foot posture groups during static standing.Materials and Methods: In this comparative cross-sectional study, a total of 75 distance runners were divided into 5 groups using the foot posture index. The foot function and knee and foot range of motion were assessed using the Foot And Ankle Ability Measure questionnaire (FAAM) and the goniometer, respectively. The mean of the plantar pressure percentage and the mean of the contact area on the forefoot and rearfoot were investigated during static standing. One-way ANOVA was used to compare the outcomes between the groups.Results: Among the groups, the normal foot group showed the highest scores in the activities of daily living subscale and sport subscale. Compared with the other groups, the highly-pronated foot group had a significantly greater range of motion in the ankle plantar flexion (P0.0001), respectively.Conclusion: Based on the results of this study, the foot posture is an important option that could affect function and range of motion of foot and ankle and distribution of the plantar pressure and plantar contact area.

Noisy galvanic vestibular stimulation (nGVS) involves the application of a weak, noisy, electrical current to the vestibular end organs and their afferent nerves, through electrodes placed bilaterally over the mastoid process. Center of pressure (COP) sway was shown to decrease during nGVS under conditions of static standing posture. However, whether nGVS can improve balance functions other than the static standing posture remains unclear. This study aimed to elucidate the effects of nGVS on COP sway during one-legged standing. We randomly assigned 36 participants to either a control group (sham stimulation), a 0.2 mA group (nGVS at 0.2 mA), or a 0.4 mA group (nGVS at 0.4 mA). All participants were measured for COP sway standing on one leg, with open eyes, both before and during stimulation. In the 0.2 mA group, the sway path length, mediolateral mean velocity, and anteroposterior mean velocity decreased during stimulation compared with before stimulation. Conversely, no significant differences in COP sway were detected for either the control group or the 0.4 mA group. The stimulation effects for all COP sway parameters were significantly higher in the 0.2 mA group than in either the control group or the 0.4 mA group. The results of this study suggested that nGVS not only decreases COP sway during static standing postures but can also reduce COP sway during one-legged standing.

To determine the foot kinematics of the depth-jump in healthy adults. We examined the usefulness of a multi-segment foot model for a movement that requires impact absorption and force exertion on the foot. Twenty healthy adults (ten men, ten women) performed a depth-jump from a 40-cm height box on to force plates. We analyzed foot motion on the landing and jump preparation phases using the Rizzoli Foot Model. A pattern of foot motion was observed during the depth-jump. Although there were no differences of the foot structure at the static standing position with respect to sex, the maximum angle of the medial longitudinal arch (MLA) in the landing phase was significantly greater in women than in men (p = 0.017). The maximum angle of the MLA in the landing phase was strongly negatively correlated with the jump height (r = − 0.6, p = 0.05). By using a multi-segment foot model, it was possible to observe a common foot motion pattern among subjects, even during a quick movement such as the depth-jump. We suggest that motion analysis using the multi-segment foot model will be useful in evaluating the foot functions of impact absorption and force exertion during a dynamic movement such as the depth-jump.

The infrapatellar fat pad is an adipose tissue in the knee that facilitates the distribution of synovial fluid and absorbs impulsive actions generated through the joint. The correlation between morphological configuration and mechanical properties is analyzed by a computational approach. The microscopic anatomy of the infrapatellar fat pad is studied aiming to measure the dimension of adipose lobules and the thickness of connective septa. Results from histomorphometric investigations show that the infrapatellar fat pad is an inhomogeneous tissue, constituted by large lobules in the superficial part and smaller lobules in the deepest one. Finite element models of the infrapatellar fat pad are developed. The first model considers the inhomogeneous conformation of the infrapatellar fat pad, composed of micro- and macro-chambers, while the second model considers a homogeneous distribution of adipose lobules with similar dimensions. Computational analyses are performed considering the static standing configuration and the passive flexion–extension movement. The computational results allow us to identify the different stress and strain fields within the tissue and to appreciate the variation of the mechanical performance of the overall system considering the distribution of adipose lobules. Results show that the distribution of adipose lobules in macro- and micro-chambers allows major deformation of the infrapatellar fat pad, decreasing the stress inside the tissues.

The article examines the motor activity of students of musical arts using the Framingham method and identifies the ways to increase it through organized recreational activity and rational organization of free time. The data revealed a significant decrease of average indicators and lack of higher levels of motor activity for students of musical art. The total value of daily motor activity at basic, sedentary, and small levels is 91.6% among students. The assessment of motor activity showed that students of I and II year do not exhibit high levels of motor activity. Students in their third year of study showed very low motor activity. It is revealed that a lack of motor activity in students of music arts is associated with the static standing/sitting position to improve professional skills and the irrational distribution of free time. The results obtained prove that it is highly important to increase the motivation of students of musical arts to exercise and engage in sports.

Introduction Falling is a leading cause of injury-related death. Previous studies reported that an impairment of standing balance is one of the causative factors associated with falling. The combined use of static and dynamic stretching has been reported as a treatment method for improving standing balance. As one of the combined methods, stretching based on Mezieres’ concept, which has an efficacy on the improvement of body flexibility, has been used. However, it is not fully clear whether stretching based on Mezieres’ concept can improve standing balance. This study aimed to examine the effects of combined method of static and dynamic stretching of anti-gravitational muscles based on Mezieres’ concept on body flexibility and standing balance. Methods This study employed a quasi-randomized controlled trial design. Thirteen subjects were assigned randomly to one of two groups: stretching or control. A sit and reach test (SRT), functional reach test (FRT), and total trajectory length of center of pressure (COP) during static standing were assessed at pre- and post-intervention. An independent t-test was used to compare the rate of improvement between both groups at each assessment. Results The stretching group demonstrated a significantly larger rate of improvement in the total trajectory length of COP compared to the control group. In the SRT and FRT, the stretching group showed a trend toward improvement compared to the control group, but did not achieve statistical significance. Conclusions The combined use of static and dynamic stretching of anti-gravitational muscles might have the potential to improve the standing balance.

[Purpose] We aimed to determine the cause of floating toe syndrome, along with methods for correction and prevention. [Participants and Methods] We recruited 93 Japanese male students. Participants were grouped, according to primary sport, as Sprinters (SPR), Swimmers (SWM), Gymnasts (GYM), Kendoists (KND) and Controls (CON). Degree of floating toe syndrome was measured according to whether any toe was not in full contact with the ground in a static standing posture—the Floating Toe Point (FTP). Two points were given for each toe that was not at the FTP. The sum of the FTP was defined as the Floating Toes Score (FTS), and was classified as follows: Normalcy (over 18 points), Incomplete Contact (between 10 and 17 points), and Floating Toes (Under 9 points). [Results] The mean FTS for all participants (10.40 ± 5.803) met the criteria for Floating Toes. Scores were highest for SWMs (13.46 ± 5.710), followed by GYMs (13.26 ± 4.505), and SPRs (12.00 ± 4.870), who all met the criteria for Incomplete Contact. Both KNDs (6.55 ± 5.409) and CONs (9.45 ± 4.824) met the criteria for Floating Toes. [Conclusion] SWMs had the highest FTSs, followed by GYMs, and SPRs. KNDs had the lowest FTS. However, no group was classified as Normal. We suggest that athletes who practice or train with bare feet do not necessarily have higher FTSs, if evaluated in the standing posture.

Background The human foot has adapted specifically to support body weight when standing upright. At the base of the postural control system, the unique arch structure of the foot still has an uncertain role in human upright standing. Because the toe flexor muscles help to support the foot arches, they might be an important contributor to postural stability. However, no research has identified the influence of the toe flexor strength or the foot arch height on postural stability in static upright standing. Research question: The aim of this study was to examine whether the toe flexor strength and the foot arch height were related to postural stability in static standing in healthy young individuals. Methods Fifty healthy young individuals were recruited into this cross-sectional study. Toe flexor strength was measured using a toe grip dynamometer, and it was normalised by body mass (rTFS). Foot arch height was assessed as the distance between the navicular tuberosity of the foot and the floor, and it was normalised by height (rFAH). Postural stability was evaluated using the path of the centre of pressure (COP) during double-leg standing with eyes open and single-leg standing with eyes open. Results rTFS and rFAH were 2.6 ± 0.8 N/kg and 2.8 ± 0.4%, respectively, and they were not significantly correlated (r = 0.094), indicating that they were independent variables. The results of Pearson’s correlation analysis revealed that any body size related variables (height, body mass, BMI) were not significantly correlated with COP variables under either double-leg or single-leg standing, rTFS was not significantly correlated with COP variables under either double-leg or single-leg standing and rFAH was not significantly correlated with COP variables under double-leg standing. Significance Toe flexor strength has no significant role in maintaining postural stability during static upright standing.

Background This pilot study was to examine the feasibility and tolerance of whole body vibration therapy (WBVT) for children and adults with moderate severity of cerebral palsy (CP) being graded as levels III or IV on the Gross Motor Function Classification Scale (GMFCS). Methods Study participants received the additional WBVT when standing still on the vibration platform for three 3-min bouts of vibration (20 Hz, 2 mm amplitude), 4 days per week for 4 weeks. In addition to questions relating to feasibility and participants’ opinions, assessment at baseline and completion of the intervention included the Gross Motor Function Measure-66 Item Set (GMFM-66 IS), 2-min walk test (2MWT), Timed Up and Go test (TUG) and Pediatric Evaluation of Disability Inventory (PEDI). Wilcoxon Signed Ranks test was used to compare the results. Results Fourteen participants (mean age = 25.25 years SD 3.71; 9 males, 64%; GMFCS level III n = 13, 92%) were recruited and completed the study. The attendance rate was over 90% with no adverse events. All participants tolerated the protocol which was satisfactorily delivered in a clinical setting. Conclusions The present WBVT protocol was feasible, safe and well-tolerated by the participants with moderate severity of CP, justifying future studies with larger samples and more rigorous study design. Trial registration The present study has been registered under the ClinicalTrials.gov (NCT03375736) and the date of registration commenced on 18 December 2017.

Excessive foot pronation during static standing, walking and running has been reported as a contributing factor for the development of medial tibial stress syndrome (MTSS). The motion of foot pronation consists of hindfoot and forefoot motion. However, no previous studies have investigated forefoot and hindfoot kinematics during walking and running in subjects with MTSS. The current study sought to compare hindfoot and forefoot kinematics between subjects with and without MTSS while walking and running. Eleven subjects with MTSS and 11 healthy controls (each group containing 10 males and one female) participated in the current study. Segment angles of the hindfoot and forefoot during walking and running barefoot on a treadmill were recorded using three-dimensional kinematic analysis. An independent t-test was used to compare kinematic data between groups. Subjects with MTSS exhibited significantly greater hindfoot eversion and abduction (p < 0.05) during walking and running than subjects without MTSS, significantly greater forefoot eversion and abduction (p < 0.05) during walking, and significantly greater forefoot abduction during running (p < 0.05). Hindfoot and forefoot kinematics during walking and running were significantly different between subjects with and without MTSS. For prevention and rehabilitation of MTSS, it may be important to focus on not only hindfoot but also forefoot kinematics during both running and walking. (c) 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res

Background Physiological/biomechanical systems display high degrees of complexity in their corresponding physiological and/or biomechanical outputs, indicative of normal healthy physiological functioning, though little attention has been paid to potential mechanisms which may affect complexity. Center of pressure (CoP) dynamics also display high degrees of complexity and may be affected via altered respiratory-motor interactions such as during voluntary control of breathing. Purpose The purpose of this study was to investigate the differences in the complexity of CoP dynamics during autonomous vs. voluntary control of breathing and between different voluntarily controlled breathing conditions. Methods Center of pressure recordings were taken from 18 older adults during static standing under three different breathing conditions: 1) neutral breathing, 2) abdominal breathing, and 3) thoracic breathing, the first constituting the autonomous breathing condition and the latter two constituting voluntarily controlled breathing conditions. CoP dynamics were quantified using sample entropy, standard deviation, 95% sway area, and average radial velocity. Repeated measure MANOVAs were used to assess the effect of breathing on CoP dynamics, with top-down application of ANOVAs and pairwise comparison as needed. Results Voluntary control of breathing during both conditions resulted in significantly higher CoP variability and lower sample entropy than during autonomous control of breathing in the mediolateral direction, indicating less complex dynamics and loss of system control. No significant differences between voluntary breathing conditions were observed. Conclusion Voluntary control of breathing significantly affected on CoP dynamics during static standing. The complexity of the postural control system may be affected via alterations in respiratory-motor interactions.

[Purpose] The purpose of this study was to evaluate the early effects of a knee-ankle-foot orthosis on static standing balance in people with subacute stroke. [Participants and Methods] Timed static standing balance in four standing conditions (feet apart with eyes open, feet apart with eyes closed, feet together with eyes open, and tandem stance with eyes open) was assessed in 29 inpatients (mean age: 67.3 ± 13.3 years) with subacute stroke with and without a knee-ankle-foot orthosis on the paretic lower limb. [Results] In the group of participants who were unable to stand without a knee-ankle-foot orthosis, the proportion of participants who were able to stand with a knee-ankle-foot orthosis was significantly increased in the following conditions: feet apart with eyes open and feet apart with eyes closed. In the group of participants who were able to stand without a knee-ankle-foot orthosis, the mean duration of time for which the participants with a knee-ankle-foot orthosis were able to stand was significantly longer than that for those without a knee-ankle-foot orthosis for all standing conditions. [Conclusion] A knee-ankle-foot orthosis may be a useful assistive device to support static standing balance for people with subacute stroke.

BACKGROUND: Pain in the lower extremities is common among blue-collar workers, with prolonged static standing as a potential risk factor. However, little is known about the association between diurnal accelerometer measures of static standing and pain in the lower extremities, and the potential importance of temporal patterns of static standing for this association.RESEARCH QUESTION: We aimed to investigate the cross-sectional association between accelerometer measures of total static standing time and temporal patterns (bout duration) of static standing (short: 0-5 min; moderate: >5-10 min; and long bouts: >10 min) during total day, work and leisure and pain intensity (on a 0-10 scale) in hips, knees and feet/ankles.METHODS: Accelerometers were used to measure static standing during four consecutive days among 677 blue-collar workers. Linear regression analyses were used to investigate the association between static standing time and pain intensity in the lower extremities.RESULTS: Total static standing time comprised, on average, 3.9 h per day. 72.6% of the workers were exposed to long bouts of static standing, averaging 0.1 h per day. Short bouts of static standing were positively associated with hip and knee pain during total day, and positively associated with knee pain during work. Also, total static standing time during leisure was positively associated with knee and hip pain. A negative, but not significant, association was found for static standing in moderate bouts at work and hip pain.SIGNIFICANCE: Even though the associations found were weak, these findings suggest that the temporal pattern of static standing is of importance for pain in the lower extremities. Future research should examine the possibility that moderate bouts of standing could play a role in preventing lower extremity pain.

Objective To synthesise and analyse the current evidence regarding changes in joint position sense (JPS) and standing balance in people with whiplash-associated disorder (WAD) taking the presence or absence of dizziness into account. Data sources PubMed, CINAHL Plus, Web of Science, Embase, MEDLINE and APA PsycINFO were searched by two independent reviewers from inception until August 2020 and reference lists of all included studies were also reviewed. Study selection Only cross-sectional studies that measured JPS and/or standing balance between people with WAD vs. healthy controls (HC) or people with WAD complaining of dizziness (WADD) vs. those not complaining of dizziness (WADND) were selected. Data extraction Relevant data were extracted using specific checklists and quality assessment was performed using Downs and Black Scale (modified version). Data synthesis Twenty-six studies were included. For JPS, data were synthesized for absolute error in the primary plane of movement for separate movement directions. For standing balance, data were synthesized for traditional time- and frequency domain sway parameters considering the conditions of eyes open (EO) and eyes closed (EC) separately. For meta-analysis, reduced JPS was observed in people with WAD compared to HC when the head was repositioned to a neutral head position (NHP) from rotation (standardised mean difference [SMD] = 0.43 [95%: 0.24–0.62]) and extension (0.33 [95%CI: 0.08–0.58]) or when the head was moved toward 50° rotation from a NHP (0.50 [0.05–0.96]). Similarly, people with WADD had reduced JPS compared to people with WADND when the head was repositioned to a NHP from rotation (0.52 [0.22–0.82]). Larger sway velocity and amplitude was found in people with WAD compared to HC for both EO (0.62 [0.37–0.88] and 0.78 [0.56–0.99], respectively) and EC (0.69 [0.46–0.91] and 0.80 [0.58–1.02]) conditions. Conclusion The observed changes of JPS and standing balance confirms deficits in sensorimotor control in people with WAD and especially in those with dizziness.

While powered lower limb exoskeletons assist paraplegic patients in static standing positions, uncontrollable physical disturbances may lead to imbalances in the human-machine system and cause injury. To address this issue, we propose an innovative static balance control strategy for the lower limb exoskeleton. Three balance strategies that include an ankle strategy, a hip strategy, and a stepping strategy were analyzed and validated by using a balance disturbance experiment conducted on unimpaired individuals. Among them, only the stepping strategy could be adopted to restore balance by the human-machine system due to limitations of the system’s joints. A regression model was trained on experimental data of the falling point of the center of mass (COM) of unimpaired individuals following a physical disturbance. This model was then used to predict the falling point of the COM of the exoskeleton of a human-machine system. These predictions suggest that the falling point of crutches and footholds are necessary to maintain stability. Considering both stability and arm pressure, a weighting factor was employed to identify an optimal foothold of the human-machine system that ensured minimum pressure and maximum stability. Finally, a simulation showed that the application of the balance strategy enabled the exoskeleton human-machine system to recover balance over the tested controlled disturbance range.

Balance ability is a necessary exercise factor required for the activities of daily living. This study investigated the effects of short-term complex exercise (CE) and core stability exercise (CSE) on balance ability and trunk and lower-extremity muscle activation on healthy male adults. Twenty-nine healthy male adults were included. All performed CE and CSE for 1 min each, the exercise order was randomized. The primary and secondary outcomes were balance ability and muscle activation, respectively. In balance ability, CE showed a significant difference in all variables in both eye-opened and eye-closed conditions compared with the baseline (p &lt, 0.05). In comparisons among exercises, the path length and average velocity variables showed a significant decrease in the eye-opened condition, and the path length variable showed a significant decrease in the eye-closed condition (p &lt, 0.05). In muscle activation, CE showed a significant increase in the gluteus medius (Gmed) and decrease in the rectus femoris (RF), tibialis anterior (TA), and RF/biceps femoris (BF) ratio in the eye-opened condition compared to the baseline and a significant decrease in RF and RF/BF ratio in the eye-closed condition (p &lt, 0.05). Both CE and CSE improved the static balance ability. Furthermore, muscle activation significantly increases in Gmed and decreases in the RF, TA, and RF/BF ratio. Therefore, we recommend including CE in an exercise program that has the purpose of improving static balance ability.

Sit&ndash, stand workstations have shown to reduce sitting time in office workers on a group level. However, movement behaviour patterns might differ between subgroups of workers. Therefore, the objective of this study was to examine sitting, standing and stepping outcomes between habitual users and non-users of sit&ndash, stand workstations. From an international office population based in the Netherlands, 24 users and 25 non-users of sit&ndash, stand workstations were included (all had long-term access to these workstations). Using the ActivPAL, sitting, standing and stepping were objectively measured during and outside working hours. Differences in outcomes between users and non-users were analysed using linear regression. During working hours, users sat less (&minus, 1.64, 95% IC= &minus, 2.27&ndash, &minus, 1.01 hour/8 hour workday) and stood more (1.51, 95% IC= 0.92&ndash, 2.10 hour/8 hour workday) than non-users. Attenuated but similar differences were also found for total sitting time over the whole week. Furthermore, time in static standing bouts was relatively high for users during working hours (median= 0.56, IQR = 0.19&minus, 1.08 hour/8 hour workday). During non-working hours on workdays and during non-working days, no differences were found between users and non-users. During working hours, habitual users of their sit&ndash, stand workstation sat substantially less and stood proportionally more than non-users. No differences were observed outside working hours, leading to attenuated but similar differences in total sitting and standing time between users and non-users for total days. This indicated that the users of sit&ndash, stand workstations reduced their sitting time at work, but this seemed not to be accompanied by major carry-over or compensatory effects outside working hours.

Static standing postural stability has been measured by multiscale entropy (MSE), which is used to measure complexity. In this study, we used the average entropy (AE) to measure the static standing postural stability, as AE is a good measure of disorder. The center of pressure (COP) trajectories were collected from 11 subjects under four kinds of balance conditions, from stable to unstable: bipedal with open eyes, bipedal with closed eyes, unipedal with open eyes, and unipedal with closed eyes. The AE, entropy of entropy (EoE), and MSE methods were used to analyze these COP data, and EoE was found to be a good measure of complexity. The AE of the 11 subjects sequentially increased by 100% as the balance conditions progressed from stable to unstable, but the results of EoE and MSE did not follow this trend. Therefore, AE, rather than EoE or MSE, is a good measure of static standing postural stability. Furthermore, the comparison of EoE and AE plots exhibited an inverted U curve, which is another example of a complexity versus disorder inverted U curve.

BACKGROUND Identifying the functional status of patients after total knee arthroplasty is important. This study aimed to examine the differences in sit-to-stand and static standing ability balance between patients who underwent total knee arthroplasty and healthy participants. METHODS Twenty patients (mean age 70.05 years) who underwent total knee arthroplasty and 20 healthy participants (mean age 69.20 years) participated in this study. To assess the participants' sit-to-stand, the Good Balance System (Metitur Ltd, Finland) was used to measure each participant's mediolateral center of pressure (COP) displacement and time required to complete the sit-to-stand movement. To assess the participants' static standing balance, the Good Balance System was used to measure each patient's mediolateral COP displacement, anteroposterior COP displacement, and velocity moment when standing with eyes open and with eyes closed. RESULTS A significant difference was found in the mediolateral COP displacement and the time required to complete the sit-to-stand movement in the two groups (P< 0.05). A significant difference was also found in the mediolateral and anteroposterior COP displacement and the velocity moment when standing with eyes open and with eyes closed in the two groups (P< 0.05). CONCLUSIONS Patients who had total knee arthroplasty showed decreased sit-to-stand and static standing balance ability compared with the control group in the initial period after surgery.

espanolLa falta de informacion objetiva relacionada con la alineacion de las protesis es un fenomeno comun en el area. Cuando aparece una ubicacion angular inadecuada de la cavidad protesica transtibial, se ven afectados los parametros biomecanicos en la articulacion de los amputados; tambien afecta la comodidad del amputado en la posicion de pie. La presente investigacion da cuenta de los efectos de la desalineacion de la protesis transtibial en los parametros biomecanicos al medirse en terminos de angulos de las extremidades inferiores, cuando el sujeto se encuentra en la posicion bipedestada estatica. Se midieron siete condiciones de alineacion en cada uno de los 6 participantes del estudio, mientras que al participante siete (7) solo se le localizaron seis condiciones, para un total de 144 pruebas. Un sistema de medicion de angulos (goniometros digitales) permitio detectar y almacenar los cambios de los rangos articulares. El analisis estadistico de las mediciones realizadas mostro una variacion intra y entre sujetos, por lo que se establecio una metodologia para la obtencion del modelo de alineacion estatica. EnglishThe lack of objective information concerned to prostheses alignment is a common phenomenon in the area. When an inadequate angular location of the transtibial prosthetic socket appears, the biomechanical parameters in the joint in the amputees are affected; it also affects the amputee’s comfort in the standing position. The effects of transtibial prosthesis malalignment on biomechanical parameters were measured in terms of lower limb angles, when the subject is in the static standing position. Seven insertion alignment conditions were measured in each of the 6 participants of the study, whereas participant seven (7) only six conditions were located, for a total number of 144 tests. The socket angle and the joint angles, were recorded in computer files. The statistical analysis of the measurements carried out showed variation intra and inter subjects, so a methodology for the obtaining of the static alignment model was stated.

This study aims to investigate the cross-sectional association between objectively measured total time and temporal patterns of static standing (short bouts: 0–5 min; moderate bouts: >5–10 min; and long bouts: >10 min) during work and leisure and low back pain (LBP) among 698 blue-collar workers. Workers reported LBP on a 0–10 scale. The association between time spent on static standing and LBP was tested with linear regression. A positive association with LBP intensity was found for long bouts of static standing (β = 0.27) during total day (work + leisure), and total static standing time at leisure (β = 0.12). No significant associations were found for static standing during work and LBP intensity. These findings indicate that particularly long bouts of static standing over the entire day contribute to LBP in blue-collar workers. Practitioner Summary: The association between LBP and static standing time was investigated. This study indicates that prolonged time standing during total day and standing during leisure are positively associated with LBP among blue-collar workers. Therefore, practitioners should consider long periods of standing as a potential risk factor for LBP.

Background The vestibular system is involved in the control of standing balance. Galvanic vestibular stimulation (GVS) is a noninvasive technique that can stimulate the vestibular system. In recent years, noisy GVS (nGVS) using noise current stimulation has been attempted, but it has not been clarified whether it affects postural sway in open-eye standing. Objective The purpose of this study was to clarify the influence of nGVS on the center of pressure (COP) sway measurement in open-eye standing postural control and identify the responders of nGVS. Methods nGVS (0.1–640 Hz) was delivered at 0.4 and 1.0 mA over the bipolar mastoid. COP sway root mean square area, sway path length, medio-lateral (ML) mean velocity, and antero-posterior (AP) mean velocity before and during nGVS in an open-eye standing posture was measured. Results nGVS at 0.4 and 1.0 mA significantly reduced sway path length, mean velocity. The stimulation effect of nGVS was also large in subjects with a long sway path. For subjects with high COP sway of Baseline, nGVS was effective even with stimulation for a short duration (5 s). Conclusions These findings suggest that nGVS improves postural sway in an open-eye standing posture among young subjects.

With marathon-running grew in popularity, the effect of long-distance running on plantar pressure has been more attractive. It has been proposed that long-distance running influences the deviation in the center of pressure (COP) during standing and the changes to plantar pressure during walking. The objective of this study was to observe the effects on the COP motion amplitude of static standing and the plantar pressure distribution of walking after long-distance running. The influence of a 10-km run on changes to plantar pressure was assessed during standing and walking. Plantar pressure was measured before and immediately after running. In the study, seven males and five females participated in barefoot tests of static standing and dynamic walking. In the static standing tests, COP was measured under the following four ordered conditions: (1) bipedal, eyes open, standing; (2) bipedal, eyes closed, standing; (3) unipedal, eyes open, standing and (4) unipedal, eyes closed, standing. Under each condition, the data was collected while a stable standing posture for 10 s. In the dynamic walking tests, the contact duration and plantar pressure were recorded. The standing tests results revealed no significant differences between males and females while slight differences before vs. after running. Running for a single time had no effect on COP deviation during standing. The walking tests results revealed an initial landing on the lateral heel. After landing on the lateral heel, the females quickly transferred to the medial heel. The movement of the pressure to the medial heel was slower in males than females. After running, the pressure of females was more inward, while that of males was more outward under the metatarsal zones in the propulsion phase.

Manual perturbation training improves dynamic knee stability and functional performance after anterior cruciate ligament rupture (ACL-rupture). However, it is limited to static standing position and does not allow time-specific perturbations at different phase of functional activities. The purpose of this study was to investigate whether administering mechanical perturbation training including compliant surface provides effects similar to manual perturbation training on knee functional measures after an acute ACL-rupture. Sixteen level I/II athletes with ACL-ruptures participated in this preliminary study. Eight patients received mechanical (Mechanical) and 8 subjects received manual perturbation training (Manual). All patients completed a functional testing (isometric quadriceps strength, single-legged hop tests) and patient-reported measures (Knee Outcome Survey- Activities of Daily Living Scale (KOS-ADLS), Global Rating Score (GRS), International Knee Documentation Committee 2000 (IKDC 2000) at pre- and post-training. 2X2 ANOVA was used for data analysis. No significant group-by-time interactions were found for all measures (p>0.18). Main effects of time were found for single hop (Pre-testing: 85.14%+21.07; Post-testing: 92.49%+17.55), triple hop (Pre-testing: 84.64%+14.17; Post-testing: 96.64%+11.14), KOS-ADLS (Pre-testing: 81.13%+11.12; Post-testing: 88.63%+12.63), GRS (Pre-testing: 68.63%+15.73; Post-testing: 78.81%+13.85), and IKDC 2000 (Pre-testing: 66.66%+9.85; Post-testing: 76.05%+14.62) (p

This study evaluated the effects of active versus static standing on short-duration computer task performance, postural risks and perceived pain, comfort and fatigue. A repeated measures, within-subjects study was conducted in which 16 participants performed 40 trials of a computer-based homing task in two active standing versus a static standing condition. Computer task performance was operationalized using mousing and typing speed as the measures; postural risk was evaluated using the Rapid Entire Body Assessment (REBA). Perceived scores for pain, comfort and fatigue were reported through a survey administered at baseline and after each standing task condition. Results suggest that for short-duration computer tasks, there was no significant difference in typing speed between active and static standing. However, mousing speed was significantly higher in static standing compared to a specific active standing condition. Overall levels of perceived pain, comfort and fatigue did not differ significantly between active and static standing.

The purpose of this study was to investigate the effect of asymmetry improving on complex intervention exercise for posture stabilization of adolescent idiopathic scoliosis. A total of 41 female elementary scoliosis students participated in the purposive sampling study. Those was used for 3 dimension structural analysis in order to analyze the spinal scoliosis and body alignment. For this study, the subjects were performed for 60 minutes per day and 3-times a week during 12-weeks for complex intervention exercise program, and paired t-test was performed at the 0.05 level of significance. The results of spine structural analysis showed that the torsion angle and rotation angle of the pelvis and the side angle of the spine were statistically significant after exercise compared to before exercise. There was no statistical significance in the trunk elements, but the asymmetry factor after exercise was more relaxed than in the anteroposterior and mediolateral tilt angle and torsion angle. Therefore, the asymmetry factor was relaxed after exercise and showed positive tendency in static standing.

A certain pressure (static load) acts as grounding to support the human body during static standing. However, a pressure load from the leg (dynamic load) changes with time and may differ between stepping in place with eyes open and closed. This study aimed to examine the difference in foot pressure between the eyes open and closed conditions and among age-levels during stepping with a stipulated tempo. The participants were 86 healthy men aged between 10 and 80 years. Sample sizes for each decade’s age group ranged from 10 to 13. We measured their foot pressure while they stepped 20 times while matching a tempo of 100 bpm. A mean of left–right foot pressure (ratio of pressure to weight) of 20 times was used as an evaluation parameter. Stepping with eyes open and closed produced a significant, strong relationship (r = 0.90) in the foot pressure value. In the results of two-way ANOVA (eyes open/closed difference and age-level difference) and multiple comparisons, eye conditions showed a significant difference only in participants who were in their 80s, with greater foot pressure with eyes open. When stepping with eyes open, 10 and 20 age-levels had greater foot pressure than 50 to 80 age-levels, and 30 to 60 had greater pressure than 70 and 80 age-levels. When stepping with eyes closed, 10 and 20 age-levels had greater pressure than 40 to 80 age-levels, and 30 to 80 had greater pressure than 70 and 80 age-levels. Although the foot pressure value showed a significant linear regression with age both with eyes open and closed, an insignificant difference was found between regression coefficients. In conclusion, regardless of eyes open or closed, the foot pressure value during stepping with a stipulated tempo decreases with age and is low in the eyes closed condition compared to eyes open in the super elderly over 80-years-old, thus differing from other age-levels.

Summary Hamstring tightness has been documented not to be related to the pelvic tilt position during static standing posture, but there is limited data on the relationship between hamstring muscle length (HML) and pelvic tilt range (PTR) during the dynamic movement of forward bending. This ex-post facto study was designed to compare each of HML and PTR in individuals with low back pain (LBP) and counterparts without LBP, and the relationship between HML and PTR in individuals with and without LBP. The study involved 30 purposively recruited individuals with LBP and 30 height and weight-matched individuals without LBP. Participants' PTR and HML were assessed using digital inclinometer and active knee extension test respectively. Data were analyzed using t-test and Pearson Correlation (r) at α = 0.05. Participants without LBP had significantly longer (p = 0.01) HML than those with LBP but the PTR of both groups were not significantly different. HML and PTR had indirect but not significant correlations in participants with and without LBP. Hamstring muscle length is significantly reduced in individuals with LBP but it has no significant correlation with pelvic tilt range. Pelvic tilt range reduces as hamstring muscle length increases.

This study examined the effect of participant physique on the increase in shank circumference (ISC) for the 2-hr standing. We recruited 20 healthy male participants (10 with normal body mass index (BMI) and 10 who were overweight) and examined their ISC every 20 min under two prolonged standing conditions (static and intermittent standing). Results showed that prolonged standing types, physiques, and sustained time significantly influence the ISC. The ISC during intermittent standing (mean = 0.38 cm) was significantly lower than that observed during static standing (mean = 0.52cm). That is, 1 min of relaxation after every 20 min of standing can effectively relieve the load on the participants’ shank during standing. The normal (BMI = 21.9) group exhibited a significantly higher ISC than the overweight group (BMI = 26.5) did. This increase was also reflected in the subjective discomfort rating results. The standing type may be more dominant than the worker's physique on the lower-limb loading when performing prolonged standing tasks.

Objectives: To investigate the effects of concurrent tasks (motor and cognitive) on postural control performance in children with traumatic brain injury (TBI) compared to typically developing (TD) control subjects. Methods: Sixteen children with TBI (aged 11.63±1.89 years) and 22 TD controls (aged 11.41±2.24 years) participated in this case-control study. This study was conducted between May 2016 and March 2017. Each child performed static standing under 3 different conditions: single, concurrent motor, and concurrent cognitive task. Postural control performance measure includes sway area, anterior-posterior (AP) sway velocity, medio-lateral (ML) sway velocity, AP sway distance and ML sway distance as measured using the APDM® Mobility Lab (Oregon, Portland). A repeated-measure analysis of variance was used to analyse the data. Results: We found that children with TBI showed significantly more deterioration in postural control performance than TD children (p

This paper presents a novel sensor-to-segment calibration procedure for inertial sensor-based knee joint kinematics analysis during cycling. This procedure was designed to be feasible in-field, autonomously, and without any external operator or device. It combines a static standing up posture and a pedaling task. The main goal of this study was to assess the accuracy of the new sensor-to-segment calibration method (denoted as the &lsquo, cycling&rsquo, method) by calculating errors in terms of body-segment orientations and 3D knee joint angles using inertial measurement unit (IMU)-based and optoelectronic-based motion capture. To do so, 14 participants were evaluated during pedaling motion at a workload of 100 W, which enabled comparisons of the cycling method with conventional calibration methods commonly employed in gait analysis. The accuracy of the cycling method was comparable to that of other methods concerning the knee flexion/extension angle, and did not exceed 3.8&deg, However, the cycling method presented the smallest errors for knee internal/external rotation (6.65 &plusmn, 1.94&deg, ) and abduction/adduction (5.92 &plusmn, 2.85&deg, ). This study demonstrated that a calibration method based on the completion of a pedaling task combined with a standing posture significantly improved the accuracy of 3D knee joint angle measurement when applied to cycling analysis.

[Purpose] The purpose of this study was to investigate the effects of the menstrual cycle on the static balance of healthy young women. [Subjects and Methods] Eighteen healthy young subjects (mean age 19.1 years; weight 57.5 kg; height 159.9 cm) participated in this study. The Good Balance system was used to measure the postural sway speed and velocity moment of subjects in the static standing posture. Subjects were measured for static balance between 1 and 3 days after menstruation and 13 days after menstruation. [Results] The velocity moment of postural sway was significantly higher at 13 days after menstruation. [Conclusion] Our results indicate that the menstrual cycle affects the static balance of healthy subjects. During the menstrual cycle, intensity for balance exercises in females should be carefully controlled for injury prevention.