Change in cup orientation from supine to standing posture: a prospective cohort study of 419 total hip arthroplasties.

BACKGROUND AND PURPOSE: Arthroplasty surgeons traditionally assess cup orientation after total hip arthroplasty (THA) on supine radiographs. Contemporary hip-spine analyses provide information on standing, functional cup orientation. This study aims to (i) characterize cup orientations when supine and standing; (ii) determine orientation differences between postures; and (iii) identify factors associated with magnitude of orientation differences. METHODS: This is a 2-center, multi-surgeon, prospective, consecutive cohort study. 419 primary THAs were included (57% women; mean age: 64 years, standard deviation [SD] 11). All patients underwent supine and standing antero-posterior pelvic and lateral spinopelvic radiographs. Cup orientation and spinopelvic parameters were measured. Target cup orientation was defined as inclination/anteversion of 40°/20° ± 10°. A change in orientation (Δinclination/Δanteversion) between postures > 5° was defined as clinically significant. Variability was defined as 2 x SD. RESULTS: Inclination increased from 40° (supine) to 42° (standing) corresponding to a Δinclination of 2° (95% confidence interval [CI] 2-3). Anteversion increased from 25° (supine) to 30° (standing) corresponding to a Δanteversion of 5° (CI 5-6). When supine, 69% (CI 65-74) of THAs were within target, but only 44% (CI 39-49) were within target when standing, resulting in a further 26% (CI 21-30) being out of target when standing. From supine to standing, a clinically significant change in anteversion (> 5°) was seen in 47% (CI 42-52) of cases. Δanteversion was higher in women than in men (6°, CI 5-7 vs 5°, CI 4-5) corresponding to a difference of 1° (CI 1-2), which was dependent on tilt change, standing cup anteversion, age, and standing pelvic tilt. CONCLUSION: Cup inclination and version increase upon standing but significant variability exists due to patient factors.

Daily standing time, dietary fiber, and intake of unsaturated fatty acids are beneficially associated with hepatic insulin sensitivity in adults with metabolic syndrome.

Background: Obesity is associated with impaired glucose metabolism and hepatic insulin resistance. The aim was to investigate the associations of hepatic glucose uptake (HGU) and endogenous glucose production (EGP) to sedentary behavior (SB), physical activity (PA), cardiorespiratory fitness, dietary factors, and metabolic risk markers. Methods: Forty-four adults with metabolic syndrome (mean age 58 [SD 7] years, BMI ranging from 25-40kg/; 25 females) were included. HGU was measured by positron emission tomography during the hyperinsulinemic-euglycemic clamp. EGP was calculated by subtracting the glucose infusion rate during clamp from the glucose rate of disappearance. SB and PA were measured with hip-worn accelerometers (26 [SD3] days). Fitness was assessed by maximal bicycle ergometry with respiratory gas measurements and dietary intake of nutrients by 4-day food diaries. Results: HGU was not associated with fitness or any of the SB or PA measures. When adjusted for sex, age, and body fat-%, HGU was associated with whole-body insulin sensitivity (ß=0.58), water-insoluble dietary fiber (ß=0.29), energy percent (E%) of carbohydrates (ß=-0.32), saccharose (ß=-0.32), mono- and polyunsaturated fatty acids (ß=0.35, ß=0.41, respectively). EGP was associated with whole-body insulin sensitivity (ß=-0.53), and low-density lipoprotein cholesterol [ß=-0.31], and when further adjusted for accelerometry wear time, EGP was associated with standing [ß=-0.43]. (p-value for all< 0.05). Conclusions: Standing more, consuming a diet rich in fiber and unsaturated fatty acids, and a lower intake of carbohydrates, especially sugar, associate beneficially with hepatic insulin sensitivity. Habitual SB, PA, or fitness may not be the primary modulators of HGU and EGP. However, these associations need to be confirmed with intervention studies.

Effects of three-dimensional femur and tibia postures on the parameters of standing long-leg radiographs for osteoarthritic knees in elderly female subjects.

BACKGROUND: Long-leg frontal radiographs of the lower extremities are used to assess knee osteoarthritis. Given the three-dimensional (3D) nature of alignment changes in osteoarthritis, postural alterations in the femur and tibia extend beyond the coronal plane (in-plane) to include the transverse and sagittal planes (out-of-plane). This study investigates the impact of these out-of-plane factors on in-plane knee alignment parameters observed in frontal radiographs. METHODS: A total of 97 osteoarthritic knees in women were examined. Using a 3D-to-two-dimensional (2D) image matching technique, we evaluated the 3D postures of the femur and tibia in the standing position as viewed from frontal radiographs in the world coordinate system. Statistical analyses were conducted to explore associations between these 3D postures and 2D alignment parameters obtained from frontal radiographs under identical conditions. FINDINGS: The femur exhibited a medial inclination of 2.7°, a posterior inclination of 3.9°, and an internal rotation of 4.2°, whereas the tibia showed a lateral inclination of 6.4°, an anterior inclination of 6.7°, and an internal rotation of 6.7°. Both coronal and rotational postures of femur and tibia influenced the hip-knee-ankle angle, mechanical axis percentage, and medial proximal tibial angle. However, only coronal factors of tibia impacted tibial joint line obliquity relative to the floor. INTERPRETATION: Attention should be paid to the potential impact of the out-of-plane postures of the femur and tibia on parameters assessed in plain frontal radiographs of the lower extremities.

Moving from stable standing to single-limb stance or an up-on-the-toes position: The importance of vision to dynamic balance control.

Understanding the contribution vision has to dynamic balance control may help in understanding where/why loss of balance occurs during everyday locomotion. The current study determined how body-centre-of-mass (BCoM) dynamics and postural stability when moving to and holding a single-limb-stance (SS) or an up-on-the-toes (UTT) position were affected by visual occlusion. From standing on a force platform, 18 adults (mean (SD) 26.7 (4.8) years; 1.73 (0.08) m; 84.0 (22.9) kg; 7 females) completed repeated trials (x3) with and without vision in which they moved to either a SS or an UTT position (order countered-balanced), and attempted to hold that position for 2 (SS) or 5 (UTT) seconds before returning to standing. UTT trials were also repeated at a fast speed, and SS trials were repeated using both the dominant and non-dominant limb. BCoM dynamics were assessed by analysing the displacement and peak velocity of the centre-of-pressure (CoP) when moving to and from the SS and UTT positions. Balance stability was the variability in the CoP displacement/velocity when holding these positions. Results indicate that under visual occlusion, the peak CoP velocity when moving to the SS or UTT position was reduced (ES, 0.67 and 0.68, respectively), suggesting greater caution. Both the variability in the CoP displacement/velocity when holding these positions and the peak CoP velocity when returning to flat-standing increased (SS: ES, 1.0 and 0.86, respectively; UTT: ES 1.26 and 0.66, respectively), suggesting, respectively, greater instability and poorer control. The poorer control in SS trials, occurred when returning to standing from the SS position held on the non-dominant limb, and correspondingly, the reduction in SS duration when vision was occluded was greater for the non-dominant limb trails (limb-vision interaction; p = 0.042). This suggests that movements initiated/controlled by the non-dominant limb are more reliant on visual feedback than those initiated/controlled by the dominant limb.

Spinal loads during dynamic full flexion and return to standing posture in different age and sex groups: A musculoskeletal model study.

During forward flexion, spine motion varies due to age and sex differences. Previous studies showed that lumbar/pelvis range of flexion (RoF) and lumbo-pelvic ratio (L/P) are age/sex dependent. How variation of these parameters affects lumbar loading in a normal population requires further assessment. We aimed to estimate lumbar loads during dynamic flexion-return cycle and the differences in peak loads (compression) and corresponding trunk inclinations due to variation in lumbar/pelvis RoF and L/P. Based on in vivo L/P (0.11-3.44), temporal phases of flexion (early, middle, and later), the lumbar (45-55°) and hip (60-79°) RoF; full flexion-return cycles of six seconds were reconstructed for three age groups (20-35, 36-50 and 50+ yrs.) in both sexes. Six inverse dynamic analyses were performed with a 50th percentile model, and differences in peak loads and corresponding trunk inclinations were calculated. Peak loads at L4-L5 were 179 N higher in younger males versus females, but 228 N and 210 N lower in middle-aged and older males, respectively, compared to females. Females exhibited higher trunk inclinations (6°-20°) than males across all age groups. Age related differences in L4-L5 peak loads and corresponding trunk inclinations were found up to 415 N and 19° in males and 152 N and 13° in females. With aging, peak loads were reduced in males but were found non-monotonic in females, whereas trunk inclinations at peak loads were reduced in both sexes from young to middle/old age groups. In conclusion, lumbar loading and corresponding trunk inclinations varied notably due to age/sex differences. Such data may help distinguishing normal or pathological condition of the lumbar spine.

Speech-Identification During Standing as a Multitasking Challenge for Young, Middle-Aged and Older Adults.

While listening, we commonly participate in simultaneous activities. For instance, at receptions people often stand while engaging in conversation. It is known that listening and postural control are associated with each other. Previous studies focused on the interplay of listening and postural control when the speech identification task had rather high cognitive control demands. This study aimed to determine whether listening and postural control interact when the speech identification task requires minimal cognitive control, i.e., when words are presented without background noise, or a large memory load. This study included 22 young adults, 27 middle-aged adults, and 21 older adults. Participants performed a speech identification task (auditory single task), a postural control task (posture single task) and combined postural control and speech identification tasks (dual task) to assess the effects of multitasking. The difficulty levels of the listening and postural control tasks were manipulated by altering the level of the words (25 or 30 dB SPL) and the mobility of the platform (stable or moving). The sound level was increased for adults with a hearing impairment. In the dual-task, listening performance decreased, especially for middle-aged and older adults, while postural control improved. These results suggest that even when cognitive control demands for listening are minimal, interaction with postural control occurs. Correlational analysis revealed that hearing loss was a better predictor than age of speech identification and postural control.

Muscle synergy and kinematic synergy analyses during sit-to-stand motions in hallux valgus patients before and after treatment with Kinesio taping.

OBJECTIVES: To explore the impact of hallux valgus (HV) on lower limb neuromuscular control strategies during the sit-to-stand (STS) movement, and to evaluate the effects of Kinesio taping (KT) intervention on these control strategies in HV patients. METHODS: We included 14 young healthy controls (HY), 13 patients in the HV group (HV), and 11 patients in the HV group (HVI) who underwent a Kinesio taping (KT) intervention during sit-to-stand (STS) motions. We extracted muscle and kinematic synergies from EMG and motion capture data using non-negative matrix factorization (NNMF). In addition, we calculated the center of pressure (COP) and ground reaction forces (GRF) to assess balance performance. RESULTS: There were no significant differences in the numbers of muscle and kinematic synergies between groups. In the HV group, knee flexors and ankle plantar flexors were abnormally activated, and muscle synergy D was differentiated. Muscle synergy D was not differentiated in the HVI group. CONCLUSION: Abnormal activation of knee flexors and plantar flexors led to the differentiation of module D in HV patients, which can be used as an indicator of the progress of HV rehabilitation. KT intervention improved motor control mechanisms in HV patients.

Impact of Standing and Sitting Postures on Spinal Curvature and Muscle Mechanical Properties in Young Women: A Photogrammetric and MyotonPro Analysis.

BACKGROUND This study aimed to evaluate the effect of standing and sitting positions on spinal curvatures evaluated using projection moire and muscle tone and stiffness using the MyotonPRO hand-held device in young women. MATERIAL AND METHODS Thirty-three healthy women, aged 21 to 23 years, volunteered in the study. We used the projection moire method to examine spinal curvatures in both positions and the MyotonPRO device to measure the tone and stiffness of muscles in 3 regions. We evaluated the effects of positions (standing vs sitting), regions (cervical, thoracic, and lumbar), and side factor (right vs left) using multivariate analysis. RESULTS The sitting position significantly decreased the lumbosacral and thoracolumbar angles (P<0.001), but had no effect on the superior thoracic angle. Muscle tension and stiffness were the highest (P<0.001) in the cervical region and did not differ between positions (P>0.05) in this region. We found significantly higher muscle tone and stiffness in the thoracic and lumbar regions during sitting than during standing (P<0.001). There was symmetry in the muscle tone and the stiffness between the right and left sides of the spine. CONCLUSIONS The sitting posture decreased lumbosacral and thoracolumbar angles but increased muscle tension and stiffness in the lumbar and thoracic regions only. The symmetry of muscle tone and transverse stiffness in both positions was the normative value. This study provides insight into the adaptive physiological changes in spinal curvature and muscle mechanical properties in young women and serves as an important reference point for clinical studies of women.

Immediate Effect of Wearable Balance Training Device on Muscle Co-Contraction and Postural Control During Standing.

Postural control is one of the primary body functions for fall prevention. Unexpected perturbation-based balance training is effective for improving postural control. However, the effect of perturbation-based training using assistive devices on muscle activity and co-contraction for standing balance is still unclear. This training is also difficult to perform easily because it requires large instruments or expert guidance. The purpose of this study is to demonstrate the effect of perturbation-based balance training using a wearable balance training device (WBTD) on postural control. In this study, fourteen healthy young adult males were assigned to either a WBTD group or a sham group. In the intervention session, participants in the WBTD group were perturbed either left or right direction at random timing by the WBTD during tandem stance balance training. Participants in the Sham group did not receive external perturbation during tandem stance balance training. Before and after the intervention session, participants of both groups underwent unexpected lateral perturbation postural control testing (pre- and post-test). The normalized integral of electromyography (IEMG), co-contraction index (CCI), and center of pressure (COP) parameters were measured in the pre- and post-test. Experimental results showed that the WBTD group in the post-test significantly decreased left Gluteus Medius IEMG, CCI of both Gluteus Medius, and peak [Formula: see text] velocity, compared to those of the pre-test ( [Formula: see text], p =0.024 , p =0.031 , respectively). We conclude that balance training using WBTD could improve flexible postural control adjustment via cooperative muscle activation.

Feasibility and acceptability of general practitioners using sit-stand desks: a feasibility trial.

OBJECTIVES: The primary aim of this study was to investigate the feasibility and acceptability of general practitioners (GPs) using sit-stand desks to facilitate standing during consultations. A further aim was to examine the views of patients about GPs standing for their consultations. DESIGN: A pre-post single-group experimental trial design. SETTING: General practices in England, UK. PARTICIPANTS: 42 GPs (working a minimum of five clinical sessions per week) and 301 patients (aged ≥18 years). INTERVENTIONS: The intervention consisted of each GP having a sit-stand desk (Opløft Sit-Stand Platform) installed in their consultation room for 4 working weeks. Sit-stand desks allow users to switch, in a few seconds, between a sitting and standing position and vice versa, by adjusting the height of the desk. MAIN OUTCOME MEASURES: To test feasibility and acceptability, GPs reported their views about using sit-stand desks at work at baseline and follow-up. Sitting time and physical activity were also measured via accelerometer at baseline and follow-up. Patients who attended a consultation where their GP was standing were asked to complete an exit questionnaire about the perceived impact on the consultation. RESULTS: Most GPs reported using their sit-stand desk daily (n=28, 75.7%). 16 GPs (44.4%) used their sit-stand desk during face-to-face consultations every day. Most GPs and patients did not view that GPs standing during face-to-face consultations impacted the doctor-patient relationship (GPs; 73.5%, patients; 83.7%). GPs' sitting time during work was 121 min per day lower (95% CI: -165 to -77.58) at follow-up compared with baseline. CONCLUSIONS: Use of sit-stand desks is acceptable within general practice and may reduce sitting time in GPs. This may benefit GPs and help reduce sitting time in patients. TRIAL REGISTRATION NUMBER: ISRCTN76982860.

Surface electromyography analysis of ankle flexor and extensor activity under different standing stability levels.

Background: To observe the activation strategies of the ankle muscles using surface electromyography (sEMG) during single-leg standing (SLS) and both-leg standing (BLS) on flat ground (FG), soft mat (SM), and BOSU ball (BB) surfaces. Methods: Thirty healthy young adults participated in the study. The muscle activities of the tibialis anterior (TA) and gastrocnemius medial (GM) were measured on the three surfaces during SLS and BLS. Electromyographic evaluations of the TA and GM were recorded during maximum voluntary isometric contractions (MVIC). Muscle activation was evaluated using MVIC%, and muscle co-contraction was evaluated using the co-contraction index (CI). Results: A statistically significant increase was observed in the MVIC% of the TA, GM, and CI on the three surfaces during SLS compared to BLS, except for the comparison of CI on BB between SLS and BLS (t = -1.35, p = 0.19). The MVIC% of the TA and GM during SLS and BLS on BB was significantly increased in comparison with FG and SM. The CI during BLS on BB increased compared to FG (t = 3.19, p < 0.01) and SM (t = 4.64, p < 0.01). The CI during BLS on SM (t = -1.46, p = 0.15) decreased when compared to FG but without statistical significance. Conclusions: SLS and unstable surfaces can induce greater muscle activation, and SLS can have a greater influence on ankle muscles.

Correlation Between Coronal Position Sequence of Lumbar and WOMAC Score in Knee Osteoarthritis (KOA) in Standard Standing Position.

INTRODUCTION: Sagittal sequences of the spine have been shown to correlate with knee osteoarthritis (KOA), but coronal sequences and KOA have never been studied before. The study required patients to use a standard standing posture and aimed to explore the relationship between coronal position of lumbar spine and WOMAC score in KOA. METHODS: This is a cross-sectional observational study. Data on a total of 268 patients with KOA were collected. Patients were photographed in a standard standing position and lumbar-sacrum offset distance (L-SOD) and lumbar-knee offset distance (ΔL-KOD) were calculated. Patients were then divided into different groups according to different critical values and differences were compared. RESULTS: In the L-SOD of L1-3, WOMAC function (P = 0.021, P = 0.032, P = 0.001) and total score (P = 0.039, P = 0.034, P < 0.001) were different. In the L-SOD of L3-4, WOMAC pain score were different (P = 0.001, P = 0.032). At a cutoff of 13 mm, ΔL-KOD of L1-2 showed significant differences in pain part (P = 0.025, P = 0.039) and total score (P = 0.036, P = 0.050). There were significant differences in pain (P = 0.023, P = 0.027, P = 0.022), function (P = 0.048, P = 0.038, P = 0.047), and total score (P = 0.030, P = 0.027, P = 0.029) of L3-5. In the 18-mm cutoff group, only L1 and L2 have differences in the pain part (P = 0.050, P = 0.038). CONCLUSION: Coronal balance of the lumbar spine is associated with knee pain and function. The pelvis plays an important role in maintaining the coronal balance. Both the lumbar spine and the knee joint should be considered when developing the surgical strategy.

As a result of population aging, the number of patients suffering from both knee osteoarthritis (KOA) and degenerative diseases of the lumbar spine is increasing. It has been reported that patients with KOA have less symptomatic recovery after lumbar surgery, and that patients with lumbar degenerative disease have less symptomatic improvement after knee surgery than those without lumbar disease. So the knee and lumbar must be interacting in some way. Previous studies have confirmed the correlation between lumbar sagittal position sequence and KOA. However, no studies have been conducted on coronal sequences and KOA of the lumbar spine. We believe that it is because patients are required to stand naturally when taking coronal x-rays, and natural standing will lead to individual differences in the distance between the feet of patients, thereby preventing analysis. In our study, for the first time, we used a uniform stance to avoid this effect. The advantage of uniform stance is that individual differences can be excluded, and the same patient can be compared before and after treatment (because the natural stance of the patient's feet will be different before and after treatment), which is greatly conducive to the study. Our research found that the offset of the lumbar spine in the coronal position and the distance between the central vertical line of the lumbar spine and the bilateral knee joint are significantly correlated with knee pain and function. This may have some guiding significance for lumbar and knee surgery. For lumbar surgery (such as degenerative scoliosis), previous studies have suggested that short segment fixation is sufficient for patients with small Cobb angle. However, according to our conclusion, this may cause accelerated knee joint degeneration in the patient's later stages, which requires the surgeon to comprehensively evaluate the condition of the patient's knee and lumbar spine, and then formulate surgical strategies. The same is true for knee surgery: previous studies have shown no significant correlation between knee deformity and pain. Therefore, for patients with knee deformity and accompanying pain, knee surgery may not be the best choice, and it is more important to correct the deviation of the spine.

Effect of short foot exercise on lower-limb motor control function during single-leg standing in university students with flatfoot: A randomized controlled trial.

INTRODUCTION: Intrinsic foot muscles (IFMs) play an important role in lower-limb motor control, including biomechanics and neuromuscular control function. Short foot exercise (SFE) and toe curl exercise (TC) are methods used to train the IFMs, but their effect on lower-limb motor control has not been reported in previous studies. This study evaluated the effects of SFE and TC on lower-limb motor control function during single-leg standing (SLS). TRIAL DESIGN: Randomized control trial. METHOD: Thirty-six participants with flatfoot were randomly assigned to the SFE or TC group and performed exercise for 8 weeks. The assessment items were navicular drop test, toe grip strength (TGS), plantar sensation, and SLS. In the SLS assessment, we measured the mean center of pressure (COP) amplitude in the anteroposterior (AP) and mediolateral (ML) directions, onset time of gluteus maximus (G. max) and gluteus medius (G. med), angle of forefoot/hindfoot protonation and hip adduction, and lateral pelvic shift. Mixed-model repeated-measures analysis of variance and Bonferroni corrections were performed in statistical analysis. RESULTS: The SFE group showed significant differences between pre- and post-intervention for TGS (p < 0.001), COP ML (p = 0.039), and onset times of G. max (p = 0.015), and G. med (p < 0.001). The TC group showed no significant differences in all assessment items. CONCLUSION: Our finding suggests that SFE contributes to lower neuromuscular control function in people with flatfoot. TRIAL REGISTRATION: UMIN000049963.

Intersession reliability of center of pressure measurement during bipedal standing with different foot placement angles.

INTRODUCTION: The foot placement is a determinant of the base of support and influences standing balance. The reliability of postural stability tests with different foot placement angles is unclear. RESEARCH QUESTION: To determine and compare the intra- and inter-day reliability of the center of pressure-based postural stability while standing with different foot placement angles. METHOD: Twenty-five healthy adults (16 females and 9 males; age: 29 ± 6 years) completed 70 s trials of eyes open and eyes closed stability tests with 0°, 15°, 30°, and 45° angles between the feet while standing on a forceplate in three sessions: two sessions were in the same day, and the third session was one-week apart. The repeatability of measurements was tested using analysis of variance, interclass correlation, and standard error of measurements. RESULT: Throughout the three study sessions, there was no difference in postural stability while participants stood with different foot placement angles. The interclass correlation scores ranged from 0.71 to 0.96, the standard error of measurements ranged from 2.1% to 12.9%, and no significant systematic changes (p < 0.05) occurred between the testing sessions for any foot placements. Standing with a 45° angle between the feet with closed eyes showed higher reliability values than other conditions. The intra-day reliability scores were greater than inter-day reliability. DISCUSSION: The relative reliability of postural stability could be impacted by foot placement angles, which might alter ankle mobility and base of support dimensions. The advantages of larger foot placement angles on improving the relative reliability of postural stability could be better demonstrated in healthy people under challenging conditions such as standing with closed eyes. CONCLUSION: Standing with foot placement angles between 0° and 45° are reliable and a quantitative assessment of the center of pressure could be used to monitor the changes in postural stability between sessions.

Effects of routine physical therapy with and without kinesio taping in improving gross motor function in sitting and standing in spastic diplegic cerebral palsy children.

OBJECTIVE: To determine the effectiveness of Kinesio taping along with routine physical therapy on improving gross motor function in sitting and standing among spastic diplegic Cerebral Palsy children. DESIGN: Randomized controlled trial. SETTINGS: University Teaching Hospital University of Lahore, Lahore. PARTICIPANTS: 53 participants with diagnosed spastic diplegic cerebral palsy were randomly allocated in control and experimental groups. INTERVENTION: 26 Participants were treated by kinesio taping which was applied in a criss-cross manner along with routine physical therapy program while the control group (n = 27) received NDT exercise program that comprises of stretching, functional reaching, weight-bearing exercises and walking. OUTCOME MEASURE: Gross motor function was assessed using 2 components of Gross Motor Function Classification System (GMFCS-88), i.e., sitting as well as standing at the base line and after every 3rd week for 12 weeks follow up. RESULTS: In study and control group the mean score of gross motor function for sitting at baseline was 33.96 ± 3.11 and 31.50 ± 3.32 respectively. After intervention, it changed to 47.70 ± 5.46 and 43.46 ± 1.81 respectively. Mean score for Gross Motor Function calculated at base line in study and control group for standing was 27.37 ± 1.14 and 26 ± 3.01 respectively. At the end of intervention, the score improved to 36.55 ± 4.27 and 33.69 ± 2.46 respectively. CONCLUSION: In comparison to control group, significant increase in gross motor function of intervention group was seen after the 12 weeks of intervention. In this way, over back muscles the application of kinesio tape in a Criss-Cross manner may be helpful. Also it can be used as an additional approach along with routine physical therapy to improve standing and sitting in spastic diplegic children.

Enabled to Stand: A Single-subject Research Design Study Exploring Pediatric Power Wheelchair Standing Device Use.

PURPOSE: To investigate the influence of powered wheelchair standing device (PWSD) use on changes in activity/participation in children with neurodevelopmental conditions. METHODS: A mixed methods A-B-A single-subject research design was replicated with participants. The target behavior was parental perceptions of changes in children's performance of activity/participation goals measured via the Canadian Occupational Performance Measure (COPM). Secondary outcome measures included the COPM with children, an interview, and a 3-measure implementation survey. COPM data related to the target behavior were analyzed using the split-middle celeration line method. RESULTS: Four child-parent dyads participated in the study. All participants achieved statistically and clinically significant increases in COPM performance ratings for the 5 parent-identified activity/participation goals. CONCLUSIONS: For the participant dyads in this study, use of the PWSD appeared to positively influence parental perceptions of improvements in their child's performance of activity/participation goals.

Muscle synergies for multidirectional isometric force generation during maintenance of upright standing posture.

Muscle synergies are defined as coordinated recruitment of groups of muscles with specific activation balances and time profiles aimed at generating task-specific motor commands. While muscle synergies in postural control have been investigated primarily in reactive balance conditions, the neuromechanical contribution of muscle synergies during voluntary control of upright standing is still unclear. In this study, muscle synergies were investigated during the generation of isometric force at the trunk during the maintenance of standing posture. Participants were asked to maintain the steady-state upright standing posture while pulling forces of different magnitudes were applied at the level at the waist in eight horizontal directions. Muscle synergies were extracted by nonnegative matrix factorization from sixteen lower limb and trunk muscles. An average of 5-6 muscle synergies were sufficient to account for a wide variety of EMG waveforms associated with changes in the magnitude and direction of pulling forces. A cluster analysis partitioned the muscle synergies of the participants into a large group of clusters according to their similarity, indicating the use of a subjective combination of muscles to generate a multidirectional force vector in standing. Furthermore, we found a participant-specific distribution in the values of cosine directional tuning parameters of synergy amplitude coefficients, suggesting the existence of individual neuromechanical strategies to stabilize the whole-body posture. Our findings provide a starting point for the development of novel diagnostic tools to assess muscle coordination in postural control and lay the foundation for potential applications of muscle synergies in rehabilitation.

Electrocortical activity associated with movement-related fear: a methodological exploration of a threat-conditioning paradigm involving destabilising perturbations during quiet standing.

Musculoskeletal trauma often leads to lasting psychological impacts stemming from concerns of future injuries. Often referred to as kinesiophobia or re-injury anxiety, such concerns have been shown to hinder return to physical activity and are believed to increase the risk for secondary injuries. Screening for re-injury anxiety is currently restricted to subjective questionnaires, which are prone to self-report bias. We introduce a novel approach to objectively identify electrocortical activity associated with the threat of destabilising perturbations. We aimed to explore its feasibility among non-injured persons, with potential future implementation for screening of re-injury anxiety. Twenty-three participants stood blindfolded on a translational balance perturbation platform. Consecutive auditory stimuli were provided as low (neutral stimulus [CS-]) or high (conditioned stimulus [CS+]) tones. For the main experimental protocol (Protocol I), half of the high tones were followed by a perturbation in one of eight unpredictable directions. A separate validation protocol (Protocol II) requiring voluntary squatting without perturbations was performed with 12 participants. Event-related potentials (ERP) were computed from electroencephalography recordings and significant time-domain components were detected using an interval-wise testing procedure. High-amplitude early contingent negative variation (CNV) waves were significantly greater for CS+ compared with CS- trials in all channels for Protocol I (> 521-800ms), most prominently over frontal and central midline locations (P ≤ 0.001). For Protocol II, shorter frontal ERP components were observed (541-609ms). Our test paradigm revealed electrocortical activation possibly associated with movement-related fear. Exploring the discriminative validity of the paradigm among individuals with and without self-reported re-injury anxiety is warranted.

Meta-heuristic optimization algorithms based feature selection for joint moment prediction of sit-to-stand movement using machine learning algorithms.

The sit-to-stand (STS) movement is fundamental in daily activities, involving coordinated motion of the lower extremities and trunk, which leads to the generation of joint moments based on joint angles and limb properties. Traditional methods for determining joint moments often involve sensors or complex mathematical approaches, posing limitations in terms of movement restrictions or expertise requirements. Machine learning (ML) algorithms have emerged as promising tools for joint moment estimation, but the challenge lies in efficiently selecting relevant features from diverse datasets, especially in clinical research settings. This study aims to address this challenge by leveraging metaheuristic optimization algorithms to predict joint moments during STS using minimal input data. Motion analysis data from 20 participants with varied mass and inertia properties are utilized, and joint angles are computed alongside simulations of joint moments. Feature selection is performed using the Manta Ray Foraging Optimization (MRFO), Marine Predators Algorithm (MPA), and Equilibrium Optimizer (EO) algorithms. Subsequently, Decision Tree Regression (DTR), Random Forest Regression (RFR), Extra Tree Regression (ETR), and eXtreme Gradient Boosting Regression (XGBoost Regression) ML algorithms are deployed for joint moment prediction. The results reveal EO-ETR as the most effective algorithm for ankle, knee, and neck joint moment prediction, while MPA-ETR exhibits superior performance for hip joint prediction. This approach demonstrates potential for enhancing accuracy in joint moment estimation with minimal feature input, offering implications for biomechanical research and clinical applications.