Effect of Transcranial Direct Current Stimulation with Balance Training in a Middle-Aged Population: Randomized Double-Blind Sham-Controlled Trial.

Introduction: The first signs of deteriorated balance impairment begin during middle age. Early intervention could delay the fall risk in older populations; hence, addressing balance deficits during this age is crucial. The authors aimed to determine the effects of transcranial direct current stimulation (tDCS) combined with balance training (BT) on the improvement of static and dynamic balance in a middle-aged population, along with the participants' safety and satisfaction. Methods: Participants (n = 28) were randomized into two groups: active tDCS (active tDCS + BT) and sham tDCS (sham tDCS + BT). Both groups received the intervention thrice a week for 6 weeks. Dynamic and static balance were assessed by sway rate changes with eyes open and closed, and the functional reach test and a postintervention survey were conducted to assess participants' safety and satisfaction. Results: The active tDCS group showed significantly greater static and dynamic balance improvements in sway scores. The surveys demonstrated the safety of the program and satisfaction of 80% of the participants with the combined intervention. Conclusion: tDCS could be used in a middle-aged population as part of regular BT to improve balance and minimize the risk of balance deficits in older populations while ensuring patient safety and satisfaction. This study is a subanalysis of a larger clinical trial that included young adults as well (Clinical trial number: KCT0007414).

Effect of tDCS Combined With Physical Training on Physical Performance in a Healthy Population.

Purpose: The effectiveness of transcranial direct current stimulation (tDCS) combined with physical training has shown inconsistent results through research. Hence, a study utilizing a long-term tDCS application over the primary motor cortex and a large sample size is required to determine whether tDCS combined with physical training can increase physical performance (muscular strength, endurance, and explosive strength) in healthy adults. Material and methods: Fifty-six healthy adults were randomly distributed into two groups: active (active tDCS+ physical training) and sham (sham tDCS + physical training) and received the intervention three times per week for six weeks. Muscle strength was assessed using maximal isometric muscle strength (MIMS) by a digital dynamometer. Muscular endurance and lower limb explosive strength were assessed by using muscle fitness testing (MFT), and the Sargent jump test. Results: The active and sham groups exhibited significant improvement in all measured parameters in intragroup analyses. However, intergroup analyses revealed no significant difference between the groups. Conclusion: Our findings suggest that only physical training improved MIMS in the upper and lower extremities, MFT endurance scores, and lower limb explosive power. Thus, tDCS failed to demonstrate its effectiveness in a healthy population according to the protocol used in this study.

Pain Reduction and Posture Alignment Improvement in Older Adults with Chronic Low Back Pain: A Novel Approach Using Spinal Thermal Massage Bed and Calf Pneumatic Cell Compression.

BACKGROUND Chronic low back pain (CLBP) significantly affects the well-being of older adults, leading to diminished quality of life and heightened stress. Existing treatments have limited effectiveness and potential side effects. This study aimed to explore an integrative approach, employing a combination of spinal thermal massage bed (STMB) and intermittent pneumatic calf compression, as an alternative strategy for managing CLBP, improving body posture, reducing stress, and enhancing quality of life. MATERIAL AND METHODS Twenty-three participants aged 65-80 years completed a 4-week intervention involving eight sessions (2 per week) with the STMB device. Outcome measures included pain level assessed by the visual analog scale, trunk and pelvic tilting angles indicating spine curvature, stress level of the autonomic nervous system, Oswestry Disability Index, and EuroQol five-dimensions QoL questionnaire. RESULTS The study revealed significant reductions in pain intensity between baseline and mid-term scores (p=0.002) and between baseline and post-test scores (p=0.001). Moreover, notable improvements were observed in trunk and pelvic tilting angles (p<0.001) and stress scores between baseline and mid-term scores (p=0.037) and between baseline and post-test scores (p=0.019). However, no significant changes were observed in disability level or QoL. Participants expressed high satisfaction with the intervention, and no serious side effects were reported CONCLUSIONS This study provides compelling evidence supporting the safety and efficacy of combining STMB with intermittent pneumatic calf compression in reducing pain intensity and stress levels and improving trunk and pelvic tilting angles. Clinical trial number: KCT0008212.

Activation of Anterolateral Abdominal Muscles During Sling Bridge Exercises: Comparison of Different Pelvic Positions.

CONTEXT: Inappropriate activation of the anterolateral abdominal muscles affects the stability of the lumbopelvic zone and increases the appearance of pain and lesion in the area. Therefore, ways to improve its effective contraction are crucial in rehabilitation. The aim of this study was to compare the activation of the transverse abdominis (TrA), internal oblique (IO), and external oblique (EO) muscles in 3 different pelvic positions (down pelvis [DP], horizontal pelvis [HP], and up pelvis [UP]) during sling bridge exercise (SBE) to determinate which position is more effective to promote a correct contraction of the anterolateral abdominal muscles. DESIGN: Cross-sectional study. METHODS: Fifteen participants performed 3 variations (DP, HP, and UP) of a one-legged exercise called "supine pelvic lift" on a sling device. The thicknesses of the TrA, IO, and EO were recorded at rest and at the 3 positions using ultrasound imaging. Thickness, change ratio, lateral slide of TrA, and preferential and contraction activation ratio of TrA, IO, and EO were analyzed. RESULTS: TrA and IO showed greater activation (P = .01) in the UP position than the other pelvic positions. In addition, UP position decreased the activation of the EO (P = .01). CONCLUSION: Based on the results of this study, SBE in the UP position has the potential to improve normal contraction patterns of the musculature and can be used in future intervention of the lumbopelvic zone.

Immediate effect of sling exercises combined with mechanic vibration and oscillation mobilization in chronic nonspecific low back pain patients: a randomized controlled trial.

PURPOSE: This study determined whether the combined application of sling exercises (SE) with targeted vibration and oscillations using a device called the Vibraoscillator (VO) is effective in reducing pain intensity, increasing range of motion (ROM), and enhancing back-related functions in patients with chronic nonspecific low back pain (CNLBP). MATERIALS AND METHODS: Thirty-six participants were randomized into experimental (SE + VO) and control (SE) groups. Both groups received the intervention twice a week for 4 weeks. The pain was assessed using the Numerical Rating Scale (NRS), ROM was measured using the Modified-Modified Schober's Test (MMST), and the level of disability was evaluated using the Oswestry Disability Scale (ODI). In addition, the global perceived effect (GPE) was determined. RESULTS: NRS and ODI scores significantly improved after the intervention in the experimental group. Only lumbar spine extension improved significantly in the case of ROM. The GPE satisfaction rate was 14.5% higher in the experimental group than in the control group. CONCLUSION: Based on the findings obtained in this study, the combined use of VO and SE in patients with CNLBP was effective in reducing pain, improving ROM, and reducing physical disability in comparison with the treatment of only SE.IMPLICATIONS FOR REHABILITATIONChronic nonspecific low back pain is a major public health problem because it affects almost every person at least once in their lifetime.A new device called a Vibraoscillator generates horizontal vibrations and vertical oscillation movements targeted to a specific area of treatment to promote the neurofacilitation of the targeted zone, aiming for a more focused treatment than general vibrations.This device, in combination with sling exercises, is hypothesized to reduce pain and increase the mobility of the targeted zone and back-related functions in these patients.Based on our findings, the combined use of these interventions twice a week for 4 weeks was effective in reducing pain and improving the range of movement, which consequently reduced physical disability in patients with chronic nonspecific low back pain.

Effects of transcranial direct current stimulation on physical and mental health in older adults with chronic musculoskeletal pain: a randomized controlled trial.

PURPOSE: We investigated the effects of transcranial direct current stimulation (tDCS) combined with physical therapy (PT) on pain levels, physical activity levels, quality of life, and depression in older adults with chronic musculoskeletal pain. METHODS: Twenty-five older adults (9 males and 16 females), aged between 66 and 86 years (active group 77.2 ± 3.9; sham group 76.6 ± 6.2), volunteers were randomly allocated in the active (active tDCS + PT) and sham groups (sham tDCS + PT), and received the intervention three times per week for 8 weeks. Pain level, physical activity level, depression state, and quality of life were assessed based on the Visual Analog Scale (VAS), Physical Activity Scale for the Elderly (PASE), Beck Depression Inventory (BDI) scale, and Short-Form 36 Health Survey Questionnaire (SF-36), respectively. Measurements were conducted four times: at baseline, mid-intervention, post-intervention, and 1-month follow-up. RESULTS: As a result, at 8 weeks, the active group yielded greater improvements in VAS, BDI, and SF-36 scores than the sham tDCS group. At follow-up, the tDCS group led to a greater improvement in VAS, PASE, and SF-36 scores compared to sham tDCS group (p < 0.05). CONCLUSION: Our results suggest a beneficial effect of tDCS combined with PT in older adults with chronic musculoskeletal pain in the reduction of pain sensation, increment of physical activity level, increment of the quality of life, and reduction of depression incidents. This opens the possibility the possibility of using tDCS as a regular treatment for this population's physical and mental health.

The Effects of tDCS with NDT on the Improvement of Motor Development in Cerebral Palsy.

We investigated the effects of transcranial direct current stimulation (tDCS) over the primary motor cortex (M1) with neurodevelopmental treatment (NDT) on the improvement of motor development and reduction of spasticity in children with cerebral palsy (CP). Twenty-four children with CP were allocated to two groups: the tDCS + NDT group and the only NDT group, done 3 times per week for 5 weeks. The Gross Motor Function Measurement (GMFM-88) and Box and Block Test (BBT) were used to assess changes in motor development, and the Modified Ashworth Scale (MAS) was used to evaluate changes in spasticity. All measurements were carried out at 3 time points: baseline, post-intervention, and 1 month follow-up. We found improvements in the GMFM-88 total scores and in each individual GMFM-88 dimension scores, favoring the tDCS + NDT group over the only NDT group. The BBT scores improved only in the tDCS + NDT group. In addition, the MAS scores reduced in the hemibody with significant motor impairment only in the tDCS + NDT group. The present findings suggest that tDCS combined with NDT can be considered a promising intervention for children with CP, as it can enhance motor development and reduce spasticity in this population.

Influence of Anterior-Posterior External Surface Perturbation on Trunk Stability During Abdominal Stabilization Strategies While Sitting.

BACKGROUND Spinal and pelvic injuries during an unexpected perturbation are closely related to spinal stability, which is known to be controlled by abdominal stabilization maneuvers. This study aimed to evaluate the effects of unexpected perturbations on trunk stability and abdominal stabilization strategies in 42 sedentary adults while sitting. MATERIAL AND METHODS Abdominal stabilization strategies consisted of bracing and hollowing maneuvers. Abdominal bracing maneuvers (ABM) were focused on the abdominal wall muscles [inferior oblique (IO), exterior oblique (EO)], and abdominal hollowing maneuvers (AHM) were focused on deep muscle (TrA) activation. The subjects were instructed in abdominal stabilization maneuvers. Afterward, subjects were seated in a chair that could be moved forward or backward suddenly with the support surface. RESULTS Angular displacements of the upper thorax, lower thorax, and lumbopelvic during unexpected perturbation, with different abdominal stabilization maneuvers, were measured. During forward perturbation (d=0.71, F=10.324, P=0.001) and backward perturbation in high speed (d=0.62, F=9.265, P=0.011), there were significant differences in angular displacements of the upper thorax between hollowing and bracing maneuvers. Additionally, significant differences were found in the lumbopelvic angular displacement between the hollowing and bracing maneuvers (d=0.62, F=4.071, P=0.044). CONCLUSIONS Our findings indicate that the ABM is a better stabilizing technique for the upper thorax, and the AHM is a better stabilizing technique for the lumbopelvic region during unexpected perturbations at high speed in the seated position.

Patient-specific functional electrical stimulation strategy based on muscle synergy and walking posture analysis for gait rehabilitation of stroke patients.

OBJECTIVE: To evaluate a novel multi-channel functional electrical stimulation (FES) rehabilitation method based on the evaluation of patient-specific walking dysfunction. METHODS: This study investigated a novel multi-channel FES-based rehabilitation method that analysed the patient's muscle synergy and walking posture. A patient-specific FES profile was produced in the pre-evaluation stage by comparing the muscle synergy and walking posture of the patient with those of healthy control subjects. During the rehabilitation phase, this profile was used to determine an appropriate FES pulse width and amplitude for stimulating the patient's muscles as they walked across a flat surface. RESULTS: Two stroke patients with hemiplegic symptoms participated in a clinical evaluation of the proposed method involving a 4-week course of rehabilitation. An evaluation of the rehabilitation results based on a comparison of the pre- and post-rehabilitation muscle synergy and walking posture revealed that the rehabilitation enhanced the muscle synergy similarity between the patients and healthy control subjects and their quantitative walking performance, as measured by a 10-m walk test and walking speed, by up to 23.38% and 30.00%, respectively. CONCLUSION: These results indicated that the proposed rehabilitation method improved walking ability by improving muscle coordination and adequately supporting weakened muscles in stroke patients.

Effects of Transcranial Direct Current Stimulation Over the Dorsolateral Prefrontal Cortex (PFC) on Cognitive-Motor Dual Control Skills.

This randomized crossover study investigated whether anodal transcranial direct current stimulation (tDCS) over the dorsolateral prefontal cortex (dlPFC) modulates memory-guided finger isometric maintenance during single motor and dual cognitive-motor tasks, based on electroencephalogram (EEG) signals. Twenty-three healthy participants (14 female; M age = 29.130 years, SD = 10.918) underwent both sham and 2-mA stimulation sessions over the dlPFC for 20 minutes, with a minimum washout period of seven days. We analyzed finger-force isometric maintenance and event-related spectral perturbation (ERSP) of the EEG during early and later phases of both tasks. We observed a significant motor accuracy improvement (p = .014) and significant variation of force output (p = .027) with significant decrease in ERSP on the dorsomedial prefrontal cortex (dmPFC) (early phase, p = .027; later phase, p = .023) only after 2 mA stimulation. Thus, anodal tDCS over the dlPFC may improve memory-guided force control during cognitive-motor dual tasks.

Effectiveness of Simulated Horseback Riding for Patients With Chronic Low Back Pain: A Randomized Controlled Trial.

CONTEXT: A simulated horseback riding (SHR) exercise is effective for improvement of pain and functional disability, but its comparative effectiveness with the other is unknown. OBJECTIVE: The authors aimed to demonstrate the effect of a SHR exercise in people with chronic low back pain. DESIGN: A randomized controlled trial. SETTINGS: Community and university campus. PARTICIPANTS: A total of 48 participants with chronic low back pain were divided into 2 groups, and SHR exercises (n = 24) or stabilization (STB) exercises (n = 24) were performed. INTERVENTIONS: The exercises were performed for 30 minutes, 2 days per week for 8 weeks. MAIN OUTCOME MEASURES: Numeric rating scale, functional disabilities (Oswestry disability index and Roland-Morris disability), and fear-avoidance beliefs questionnaire (FABQ) scores were measured at baseline and at 4 weeks, 8 weeks, and 6 months. RESULTS: A 2-way repeated analysis of variance identified that between-group comparisons showed significant differences in the FABQ related to work scale (F = 21.422; P = .01). There were no significant differences in the numeric rating scale (F = 1.696; P = .21), Oswestry disability index (F = 1.848; P = .20), Roland-Morris disability (F = 0.069; P = .80), and FABQ related to physical scale (F = 1.579; P = .24). In within-group comparisons, both groups presented significant differences in numeric rating scale (both SHR and STB after 4 wk), Oswestry disability index (both SHR and STB after 6 mo), and Roland-Morris disability (SHR after 6 mo and STB after 8 wk) compared with baseline values. In FABQ-related physical (SHR after 4 wk) and work scales (SHR after 6 mo), there were only significant differences in the SHR compared with baseline values. CONCLUSIONS: SHR exercise for 8 weeks had a greater effect than STB exercise for reducing work-related FABQ. The SHR exercise performed in a seated position could substantially decrease pain-related fear disability in young adults with chronic low back pain.

Bilateral Transcranial Direct Stimulation Over the Primary Motor Cortex Alters Motor Modularity of Multiple Muscles.

Transcranial direct current stimulation (tDCS) over the primary motor cortex (M1) has been demonstrated to modulate the motor performance of both healthy individuals and patients with neuromuscular disorders. However, the effect of tDCS on motor control of multiple muscles, which is a prerequisite to change in motor performance, is currently unknown. Using dimensionality reduction analysis, we investigated whether bilateral tDCS over M1 modulates the coordinated activity of 12 muscles. Fifteen healthy men participated in this randomized, double-blind crossover study. Each participant received a 20-min sham and 2-mA stimulation bilaterally over M1 (anode on the right M1 and cathode on the left M1), with a minimum washout period of 4 days. Muscle activation and end-point kinematics were evaluated during a task where participants reached out to a marked target with non-dominant hand as fast as possible, before and immediately after tDCS application. We found decreased similarity in motor modularity and significant changes in muscle activation in a specific motor module, particularly when reaching out to a target placed within arm's length and improved smoothness index of movement only following 2-mA stimulation. These findings indicate that clinicians and researchers need to consider the simultaneous effect of bilateral tDCS over M1 on multiple muscles when they establish tDCS protocol to change in motor performance of patients with neuromuscular deficits.

Noninvasive brain stimulation over M1 and DLPFC cortex enhances the learning of bimanual isometric force control.

Motor learning plays an important role in upper-limb function and the recovery of lost functionality. This study aimed to investigate the relative impact of transcranial direct current stimulation (tDCS) on learning in relation to the left primary motor cortex (M1) and left dorsolateral prefrontal cortex (DLPFC) during bimanual isometric force-control tasks performed with both hands under different task constraints. In a single-blind cross-over design, 20 right-handed participants were randomly assigned to either the M1 group (n = 10; mean age, 22.90 ±â€¯1.66 years, mean ±â€¯standard deviation) or the DLPFC group (n = 10; mean age, 23.20 ±â€¯1.54 years). Each participant received 30 min of tDCS (anodal or sham, applied randomly in two experiments) while performing the bimanual force control tasks. Anodal tDCS of the M1 improved the accuracy of maintenance and rhythmic alteration of force tasks, while anodal tDCS of the DLPFC improved only the maintenance of the force control tasks compared with sham tDCS. Hence, tDCS over the left M1 and DLPFC has a beneficial effect on the learning of bimanual force control.

Effectiveness of therapeutic inflatable ball self-exercises for improving shoulder function and quality of life in breast cancer survivors after sentinel lymph node dissection.

BACKGROUND: The survival rate of breast cancer survivors (BCSs) is > 90%. Particular issues are upper arm dysfunction caused by surgery and treatments. Physical activity has been recommended to improve shoulder function and quality of life (QoL) in BCSs. However, rehabilitation programs tend not to be continuous. PURPOSE: To explore the effectiveness of therapeutic inflatable ball self-exercise for improving shoulder function and QoL in breast cancer survivors (BCSs) following breast cancer surgery. PATIENTS AND METHODS: Seventy-two BCSs were allocated to two groups, conventional self-exercise (CSE; n = 34; age, 48.9 ± 7.2 years) and therapeutic inflatable ball self-exercise (IBE; n = 38; age, 47.7 ± 8.9 years); 22 in the CSE and 23 in the IBE group completed the interventions. Both groups performed intervention for 12 weeks, three times per week and 15 min a day at least. Measurement was performed three times for shoulder range of motion (ROM), handgrip strength, Shoulder Pain and Disability Index (SPADI), and Functional Assessment of Cancer Therapy-Breast (FACT-B). RESULT: Flexion and extension of shoulder ROM showed significant differences between the two groups at 12 weeks. Flexion and extension of shoulder ROM showed significant differences for t1-t2 (p = 0.02) and t0-t1 (p = 0.04). Abduction showed a significant difference for t0-t1 (p = 0.03), t1-t2 (p = 0.02), and t0-t2 (p = 0.01). CSE (7 points) and IBE (20 points) satisfied the MDC in FACT-B total score. The MDC of the SPADI total score was 13 points in the CSE group and 9 points in the IBE group. CONCLUSION: IBE would be more appropriate to start the rehabilitation for BCSs and CSE would be effective after the pain has improved.

Muscle Synergies for Turning During Human Walking.

Muscle synergy describes reduced set of functional muscle co-activation patterns. We aimed to identify muscle synergies of turning compared with straight walking. Twelve healthy adults (men: 7, women: 5) performed straight walking (SW), left turning (LT), and right turning (RT) at self-selected speeds. By using non-negative matrix factorization (NMF), we extracted muscle synergies from sixteen electromyography (EMG) signals on the right side and assigned similar muscle synergies among SW, LT, and RT into the same cluster by combining k-means clustering and intraclass correlation coefficient (ICC) analysis. We obtained task-specific clusters of muscle synergies extracted from SW, LT, or RT condition and identified the clusters that share synergies among the conditions. The central nervous system produces specific synergies involving turning behaviors and fundamental synergies for walking.

Noninvasive brain stimulation over dorsolateral prefrontal cortex for pain perception and executive function in aging.

OBJECTIVES: Based on the evidence that the dorsolateral prefrontal cortex (DLPFC) is the main region affected by the aging process, and that tDCS modulates cortical excitability, the aim of the study is to prove the feasibility of tDCS for pain perception and executive function of community-dwelling elderly individuals. METHODS: We performed a double-blind, single-arm trial, including a sham period. 5 consecutive anodal tDCS was applied over DLPFC of twenty-four elderly for 20 min during each intervention periods (in order of Sham-1 mA-2 mA). First, we classified chronic non-inflammatory pain sites into three domain (Neck and upper extremity, low back, lower extremity). Then, we used visual analogue scale, pain self-efficacy scale, Tampa scale for kinesiophobia, and Global perceived Effect scale to observe the change in pain perception, as well as Trailing Making Test and Timed Up and Go (dual) to observe the change in executive function. The changes in maximal grip strength and 12-item Short Form survey were measured secondarily. RESULTS: In the results, we observed significant improvement in pain perception and quality of life, while executive function and grip strength did not change significantly. CONCLUSION: Our findings demonstrated the feasibility of tDCS for aging-related pain perception and suggest that further randomized controlled trials with longer duration are necessary to examine the effects on executive function.

Noninvasive Brain Stimulation over the M1 Enhances Bimanual Force Control Ability: A Randomized Double-Blind Sham-Controlled Study.

Well-coordinated bimanual force control is common in daily life. We investigated the effects of anodal transcranial direct current stimulation (tDCS) over the primary motor cortex on bimanual force control. Under a cross-over study, young adults (n = 19; female = 6, male = 13) completed three bimanual force control tasks at 5%, 25%, and 50% of bimanual maximum voluntary force (BMVF) before and after real or sham tDCS. Real tDCS enhanced accuracy at all BMVF, reduced variability at 5% BMVF, and increased coordination at 5% BMVF. Real tDCS improved force control at 5% and 25% BMVF, and especially increased bimanual coordination at 5% BMVF. These findings might have implications for establishing interventions for patients with hand force control deficits.

Isokinetic knee strength and proprioception before and after anterior cruciate ligament reconstruction: A comparison between home-based and supervised rehabilitation.

BACKGROUND: Rehabilitation after anterior cruciate ligament (ACL) reconstruction focuses on restoring knee deficiencies and function. However, the extent of the clinician's direct supervision that is required to recover knee function is unknown. OBJECTIVE: To investigate differences in isokinetic knee strength improvement, endurance, and proprioception between home-based (HBR) and supervised rehabilitation (SR). METHODS: Thirty participants were randomly allocated to each group after reconstruction. Isokinetic knee strength and proprioception were measured using the Biodex multi-joint and stability systems, respectively, before and after intervention. RESULTS: The SR group showed a significant improvement from baseline, but not the HBR group (SR group, from 1.94 ± 1.44 to 1.02 ± 0.92, p< 0.05; HBR group, from 1.69 ± 0.88 to 1.61 ± 0.90, p> 0.05). There was a significant effect of exercise type on proprioception scores after controlling for pretest values (p< 0.05). No significant difference in isokinetic knee strength was observed between the groups. CONCLUSIONS: HBR recovered knee strength as effectively as the SR, but SR was more effective than HBR for the recovery of proprioception and functional knee movement. This result indicates that guidance from health professionals play an important role in enhancing proprioception for patients following ACL reconstruction.

Comparison of scapular muscle activation during shoulder elevation in older and young adults: A pilot study.

BACKGROUND: The prevalence of degenerative shoulder disease is increasing, and most shoulder diseases are accompanied by changed activation of the scapular muscles. However, the characteristics of scapular muscle activation in older adults have not yet been reported. OBJECTIVE: The aim of this study was to investigate the effect of age and load on scapular muscle activation during shoulder abduction and flexion. METHODS: Eleven older adults (5 men, 6 women; 71.1 ± 5.3 years) and ten young adults (5 men, 5 women; 25.0 ± 2.7 years) performed shoulder elevation (abduction and flexion) with and without a dumbbell. Electromyography were recorded from the upper, middle and lower trapezius, and serratus anterior muscles in the dominant side. Muscle activation was normalized by reference voluntary contractions. RESULTS: During shoulder elevation with a dumbbell load, the activation of the middle trapezius (p= 0.036) in older adults was significantly higher than that in young adults during abduction. The activation of the upper trapezius (p= 0.001) in older adults was significantly higher than that in young adults during flexion. CONCLUSION: The older adults have a higher activation of the upper and middle trapezius during shoulder elevation with a weighted load.

Choice of Muscles for Extracting Consistent Motor Modules: The Effect of Trial-to-Trial Electromyography Repeatability / 医用生物力学

Objective To identify the effect of the repeatability of muscle activations on extraction of consistent motor modules across trials. Methods The activities of sixteen muscles in twelve subjects who consistently walked at a self-selected speed were recorded. The intraclass correlation coefficient (ICC) was used to identify inter-stride repeatability of muscle activities and motor modules. Based on the repeatability of muscle activation, three types of muscle sets were organized. Results The reliable set containing the muscles showed high ICC (>0.4), but the whole-body and mixed sets containing the muscles showed poor ICC (＜0.4). When motor modules were extracted from each set, the reliable set showed the highest repeatability of motor module extraction, but the whole-body and mixed sets presented significantly lower repeatability. Conclusions Greater repeatability of muscle activations result ed in consistent motor modules. Extraction of consistent motor modules was a critical issue, especially in real-time motion recognition based on muscle patterns.