Validity conditions of approximations for a target-mediated drug disposition model: A novel first-order approximation and its comparison to other approximations.

Target-mediated drug disposition (TMDD) is a phenomenon characterized by a drug's high-affinity binding to a target molecule, which significantly influences its pharmacokinetic profile within an organism. The comprehensive TMDD model delineates this interaction, yet it may become overly complex and computationally demanding in the absence of specific concentration data for the target or its complexes. Consequently, simplified TMDD models employing quasi-steady state approximations (QSSAs) have been introduced; however, the precise conditions under which these models yield accurate results require further elucidation. Here, we establish the validity of three simplified TMDD models: the Michaelis-Menten model reduced with the standard QSSA (mTMDD), the QSS model reduced with the total QSSA (qTMDD), and a first-order approximation of the total QSSA (pTMDD). Specifically, we find that mTMDD is applicable only when initial drug concentrations substantially exceed total target concentrations, while qTMDD can be used for all drug concentrations. Notably, pTMDD offers a simpler and faster alternative to qTMDD, with broader applicability than mTMDD. These findings are confirmed with antibody-drug conjugate real-world data. Our findings provide a framework for selecting appropriate simplified TMDD models while ensuring accuracy, potentially enhancing drug development and facilitating safer, more personalized treatments.

Altered muscle recruitment patterns during isometric shoulder abduction in individuals with chronic upper trapezius pain: a cross sectional study.

BACKGROUND: Upper trapezius (UT) pain with myofascial trigger points (MTrPs) can affect movement at the glenohumeral joint as well as at the scapulothoracic joint. The investigation of muscle recruitment patterns can discern motor control strategies. The purpose of this study was to compare shoulder muscle recruitment patterns and muscle activity according to various loads between individuals with and without chronic UT pain. METHODS: In this cross-sectional study, twenty-four participants that had UT pain with MTrPs and sex, age, body weight matched 24 controls with no UT pain were recruited. Surface EMG electrodes were attached to the UT, the serratus anterior (SA), the lower trapezius (LT) and the middle deltoid (MD). All participants performed isometric shoulder abduction with a load of 25%, 50%, or 75% of the maximum strength at 60° of shoulder abduction. The EMG activity, the activity ratio (SA/UT, LT/UT, MD/UT), and the relative contribution of each muscle activity were calculated. RESULTS: MD activity was significantly decreased in the UT pain group compared to that in the control group (p < 0.05). The EMG activity ratio of SA/UT (p < 0.025) and the relative contribution of SA activity to shoulder abduction (p < 0.05) were significantly greater in the UT pain group than in the control group in the 25% loading condition. CONCLUSION: The results of present study showed that UT pain with MTrPs may increase the relative contribution of SA activity and decrease MD activity at low loads. Altered recruitment patterns of scapular upward rotators can be altered in the proper scapular position, which results in decreased MD activity. Clinicians should consider altered recruitment patterns when managing UT pain. TRIAL REGISTRATION: Clinical Research Information Service: Clinical Research Information Service (KCT0007370; 08/06/2022).

Effects of 4-week downhill treadmill walking on the vertebral angle and postural muscle activity in participants with thoracic kyphosis and forward head posture: A comparative longitudinal study.

BACKGROUND: Maintaining correct posture and optimal spine function has become an important issue due to the increased use of computers and smartphones. OBJECTIVE: To investigate the effect of a 4-week downhill treadmill exercise (DTWE) program on participants with thoracic kyphosis and forward head posture (FHP). METHODS: Twenty-eight male participants were randomly assigned to the DTWE (n= 14) or standard treadmill walking exercise (STWE) (n= 14) group. They performed 30-minute exercise three times a week for 4 weeks. The vertebral angle was measured using a three-dimensional (3D) motion analysis system. Surface electromyography (EMG) was performed to record muscle activity in the thoracic erector spinae (TES), sternocleidomastoid muscle (SCM), and cervical erector spinae (CES). RESULTS: The DTWE group showed significant increases in the craniovertebral angle (CVA) and TES EMG activity and significant decreases in the thoracic kyphosis angle and SCM and CES EMG activity compared with those shown by the STWE group following the intervention (p< 0.05). However, lumbar lordosis or pelvic tilt angles did not differ significantly between the groups after the intervention (p> 0.05). CONCLUSIONS: DTWE can be effective in reducing thoracic kyphosis and FHP without causing compensatory movements of the lumbar spine and pelvis.

Effectiveness of non-immersive virtual reality exercises for balance and gait improvement in older adults: A meta-analysis.

BACKGROUND: Virtual reality (VR)-based physical exercise is an innovative and effective intervention strategy for healthcare in older adults. OBJECTIVE: This meta-analysis aimed to clarify the effects of VR-based balance exercise programs on various balancing abilities of older adults. In addition, the effect size of each variable was computed by total exercise time, sensor type, avatar presence, and feedback type to determine influencing factors that lead to the success of VR-based rehabilitation programs. METHODS: The databases searched were PubMed/Medline, CINAHL, NDSL, and Google Scholar. Inclusion criteria were: (1) independent older adults; (2) non-immersive VR exercise; (3) randomized controlled design; (4) both balance and gait data; and (5) written in English and Korean. The studies without information to compute effect sizes were excluded. Standardized mean difference was used to analyze the effect size (d). RESULTS: Twenty-five studies were finally included in this study. The main findings of this meta-analysis were as follows: (1) Non-immersive VR-based balance exercises are moderately and largely effective for improving overall balance function, (2) VR balance exercise was more effective for static balance than for gait, (3) VR exercise is more effective when avatars are presented and KP is provided as feedback. CONCLUSION: Total exercise time and mode of feedback are influencing factors that affect the effectiveness of VR-based balance exercises.

Comparison of shoulder functions between assembly workers with and without subacromial pain syndrome.

BACKGROUND: The occurrence of subacromial pain syndrome (SPS) is associated with the frequent handling and lifting of heavy loads and excessive repetitive work. Thus, assembly workers have a high prevalence of SPS. OBJECTIVE: The purpose of this study was to investigate differences in shoulder ROM, muscle strength, asymmetry ratio, function, productivity, and depression between workers with and without SPS. METHODS: Sixty-seven male workers (35 workers with SPS and 32 workers without SPS) participated in this study. Shoulder internal rotation (SIR), shoulder external rotation (SER), shoulder abduction (SAB), shoulder horizontal adduction ROM and SIR, SER, elbow flexion (EF), scapular depression and adduction, scapular protraction strength were measured. The asymmetry ratio was calculated using the asymmetry ratio formula; shoulder functions were measured using the shoulder pain and disability index (SPADI), disabilities of the arm, shoulder, and hand (DASH), and visual analogue scale (VAS); and Endicott work productivity scale (EWPS). RESULTS: The SPADI (p = 0.001), DASH (p = 0.001), and VAS (p = 0.001) values of workers with SPS were higher than those of workers without SPS. Also, workers with SPS had lower SIR (p = 0.001) and SAB (p = 0.002) ROM compared to workers without SPS. In addition, workers with SPS exhibited lower SIR (p = 0.012) strength than workers without SPS. Workers with SPS had higher asymmetry ratio in SIR (p = 0.015), SER (p = 0.005), and EF (p = 0.008) strength than workers without SPS. CONCLUSIONS: The SIR, SAB ROM, SIR strength, and the asymmetry ratio of SIR, SER, EF strengths could provide an important baseline comparison for the workers with SPS.

Respiratory Parameters as Predictors of Balance and Gait Ability in Patients with Stroke at Discharge.

Pulmonary complications are frequent in stroke, contributing to both mortality and morbidity rates. Respiratory parameters in such patients encompass both pulmonary function and respiratory muscle strength. Identifying respiratory function variables that influence the balance and gait ability of patients with stroke is crucial for enhancing their recovery in these aspects. However, no study has assessed predictions for a comprehensive array of balance and gait abilities in such patients. We aimed to examine whether initial respiratory muscle strength and pulmonary function can predict balance and gait ability at discharge from a rehabilitation program. Thirty-one patients with stroke were included in this prospective observational study. Multiple regression models with a forward selection procedure were employed to identify respiratory parameters (including peak expiratory flow and maximal expiratory pressure) that contributed to the results of balance assessments and gait evaluations at the time of discharge. The peak expiratory flow (PEF) served as a predictor explaining 42.0% of the variance. Similarly, the maximal expiratory pressure (MEP) was a predictor variable explaining 32.0% of the variance. PEF and MEP assessments at the initial stage as predictive factors for both balance and gait ability are important in stroke management.

Effect of intensive training with a spring-assisted hand orthosis on movement smoothness in upper extremity following stroke: a pilot clinical trial.

BACKGROUND: A commercial splinting system is designed to permit quick training in opening and closing the affected hand in order to overcome the disadvantages of previous approaches. OBJECTIVE: The purpose of this study was to assess the feasibility of intensive training using a spring-assisted hand orthosis on upper extremity in individuals with chronic hemiparetic stroke. DESIGN: Five participants for the experimental group and 5 for the control group were recruited from a local rehabilitation hospital. Subjects in the experimental group participated in 4 weeks of training using a SaeboFlex orthosis for 1 hour per day, 5 times per week. Each subject in the control group wore the same orthosis for 1 hour per day without participating in upper extremity training. Outcome measures included the Fugl-Meyer Assessment, Box and Block Test, and Action Research Arm Test; kinematic parameters were collected using a 3-D motion analysis system. RESULTS: The Fugl-Meyer assessment and the Box and Block Test score were increased significantly in the experimental group after the intervention. The resultant velocity of the wrist joint for the reach-to-grasp task decreased significantly, and the resultant velocity of the shoulder joint while performing a reach-to-grasp task at acromion height decreased significantly in the experimental group. CONCLUSION: A pilot clinical study of spring-assisted dynamic hand orthosis training is feasible in recovering the movement of the hemiparetic upper extremity.

Effect of the manual stretching maneuver for hallux valgus.

BACKGROUND: Hallux valgus (HV), which is one of the most common musculoskeletal abnormalities of the foot, is defined as the medial deviation of the first metatarsophalangeal (MTP) joint and the lateral deviation of the great toe. OBJECTS: This study aimed to investigate the immediate effects of a manual stretching maneuver (MSM) in subjects with HV. METHODS: Twenty-five subjects with a total of 25 feet with mild HV participated in the study. The MSM, consisting of global stretching of the foot and toes, traction of the hallux, local stretching for hallux, and mobilization of the MTP joint of the hallux. The HV angle between the line of the first metatarsal bone and the proximal phalanx were measured using a goniometer. The cross-sectional area (CSA) of the AbdH was measured using ultrasonography. Zebris FDM was used to measure the static plantar pressure and the movement of the center of pressure (COP) standing on one foot. The dependent variables before and after treatment were compared using paired t-tests. The significance level was set at .05. RESULTS: The HV angle significantly decreased from 20.25° to 16.96°. The CSA of the AbdH significantly increased from 14.00 mm2 to 16.11 mm2. The peak pressure on the hallux and 1st, 2nd and 3rd metatarsals increased significantly. The contact area and total pressure on the hallux significantly increased. The sway of the COP on the length of the minor axis and velocity significantly decreased. CONCLUSION: This study suggests that the MSM can be effective in decreasing the HV angle in subjects with mild HV. However, further longitudinal clinical studies are required to investigate the long-term effects of the MSM in subjects with HV.

Block and Random Practice: A Wii Fit Dynamic Balance Training in Older Adults.

Purpose: To compare the effectiveness of blocked and random practice schedules of balance training in dynamic balance abilities of older adults using Wii Fit balance game tasks. Method: Forty-one participants who were not receiving hospice care or living in a nursing home participated. Three Wii Fit balance tasks (tasks A, B, and C) were selected for training, and one task (task D) was selected as the transfer test among the nine tasks in the Wii Fit balance game software. Scores for tasks A and D were evaluated. Completion times for tasks B and C were evaluated. Moved distance for the functional reach test (FRT), completion time for the timed up and go test (TUG), and performance score for the Tinetti performance-oriented mobility assessment (POMA) were also tested as clinical balance assessment outcomes. Results: The training significantly improved the performance outcomes of clinical balance assessments and task D. There were no significant group × time interaction effects and no significant main effects by group during the acquisition and retention periods of tasks A, B, and C. However, significant main effects by time were observed for tasks A, B, and C. Conclusions: When dynamic balance training such as the Wii Fit balance system is administered to older adults in a clinical setting, either a block or a random practice schedule can be effectively used to improve the dynamic balance skills. Wii Fit-based balance training is clinically effective for improving the dynamic balance ability.

Immediate effect of insoles on balance in older adults.

BACKGROUND: In recent years, fall prevention in older adults has received considerable attention in healthcare. Among many interventions, insoles are considered cost-effective and easily adopted tools to improve balance in older people. Numerous studies have verified the immediate effects of insoles on balance in older adults. However, there is still lack of consensus regarding the immediate benefits of using insoles on balance improvement. RESEARCH QUESTION: Given this, a meta-analysis was conducted to provide more conclusive evidence about the immediate effect of insoles on balance in older adults and answer the question: "Do insoles influence balance in older people?" METHODS: PubMed, NDSL, Medline, Google Scholar, and Web of Science were searched from March to August 2018. The key terms were "insole", "elderly", "gait", "balance", "shoe", "foot", and "postural". Finally, seven primary studies were selected for this meta-analysis. The balance related outcomes were coded to compute effect sizes and the overall effect size of the standardized mean differences was analyzed. Moderating variables included kinematic variables of balance, static and dynamic balance, and type of insole. RESULTS: The overall effect size of insoles was medium (d = 0.618), which suggests that insoles are beneficial for older adults for improving balance. More specifically, this study revealed that textured and vibration insoles were the most effective types of insoles. SIGNIFICANCE: This finding supports the idea that augmented tactile and mechanical sensory input from insoles can enhance the postural control mechanisms in older adults with age-related deterioration of sensory mechanisms. The use of insoles may lead to a reduction in the rate of falls which are related to decreased quality of life in older adults.

Locomotor imagery training improves gait performance in people with chronic hemiparetic stroke: a controlled clinical trial.

OBJECTIVE: The purpose of this study was to evaluate whether locomotor imagery training leads to clinical improvements in gait after stroke. DESIGN: Pretest-posttest matched control design. PARTICIPANTS: A total of 24 people with chronic hemiparetic stroke (13 for experimental and 11 for control) were recruited in this study. INTERVENTIONS: The subjects in the experimental group participated in videotape-based locomotor imagery training five days a week for four weeks. They also conducted regular physical therapy. OUTCOME MEASURES: Kinematic gait parameters were collected using a three-dimensional motion analysis system. Functional gait performance was assessed using clinical measures: Activities-specific Balance Confidence Scale, Berg Balance Test, Dynamic Gait Index and modified Emory Functional Ambulation Profile. RESULTS: After training, walking velocity increased 0.07 +/- 0.06 m/s in the experimental group and 0.01 +/- 0.07 m/s in the control group. In the experimental group, the affected and less affected limb stride lengths increased by 0.09 +/- 0.12 m and 0.10 +/- 0.07 m respectively, whereas in the control group they decreased by 0.00 +/- 0.04 m and increased by 0.02 +/- 0.06 m, respectively. Kinematic parameters in the lower extremity joints during walking were more improved after the training in the experimental group. Confidence in balance, postural control, dynamic balance and performance time for different environmental walking situations were also improved more in the experimental group. CONCLUSION: Locomotor imagery training can be considered as a useful option for restoration of ambulation for individuals with chronic hemiparetic stroke who are unable to participate in physical gait training.

Effects of 4-week self-cross body stretching with scapular stabilization on shoulder motions and horizontal adductor strength in subjects with limited shoulder horizontal adduction: cross body stretching with stabilization.

BACKGROUND: Posterior shoulder tightness is related to shoulder conditions such as shoulder impingement and limited shoulder horizontal adduction (SHA). The purpose of this study was to compare the effects of self-cross body stretching (CBS) with and without scapular stabilization (SS) on SHA and shoulder internal rotation (SIR) range of motion (ROM) and shoulder horizontal adductor strength (SHAS) in subjects with limited SHA. METHODS: Twenty-six subjects (14 males, 12 females) with limited SHA was participated in this study. The SS group and without stabilization (WS) group were assigned randomly. The SS group performed self-CBS with SS by applying belt just under the subject's axilla. The subjects were asked to perform self-CBS 4 times a week for 4 weeks. SHA and SIR RM were measured by Clinometer smartphone application, and SHAS by hand-held dynamometer before and after 4-week self-CBS. RESULTS: 2 × 2 mixed analysis of variance (ANOVA) was used to identify the significance. If there was an interaction effect, t-test was used to confirm the simple effect. There was a significant interaction in SHA ROM and SHAS. The post-test value of SHA ROM was significantly greater in SS group than WS group (P<0.0125). In SHAS, there was no significant difference between groups (P>0.0125). CONCLUSIONS: SS during self-CBS could enhance to improve SHA, SIR ROM, and SHAS in individuals with limited SHA.

Cortical effect and functional recovery by the electromyography-triggered neuromuscular stimulation in chronic stroke patients.

We investigated the effect of electromyography (EMG)-triggered neuromuscular electrical stimulation (NMES; EMG-stim) on functional recovery of the hemiparetic hand and the related cortical activation pattern in chronic stroke patients. We enrolled 14 stroke patients, who were randomly assigned to the EMG-stim (n=7) or the control groups (n=7). The EMG-stim was applied to the wrist extensor of the EMG-stim group for two sessions (30 min/session) a day, five times per week for 10 weeks. Four functional tests (box and block, strength, the accuracy index, and the on/offset time of muscle contraction) and functional MRI (fMRI) were performed before and after treatment. fMRI was measured at 1.5 T in parallel with timed finger flexion-extension movements at a fixed rate. Following treatment, the EMG-stim group showed a significant improvement in all functional tests. The main cortical activation change with such functional improvement was shifted from the ipsilateral sensorimotor cortex (SMC) to the contralateral SMC. We demonstrated that 10-week EMG-stim can induce functional recovery and change of cortical activation pattern in the hemiparetic hand of chronic stroke patients.

The application of client-centred occupational therapy for Korean children with developmental disabilities.

The aim of this paper was to investigate the effectiveness of client-centred occupational therapy using the Canadian Occupational Performance Measure (COPM) and the Assessment of Motor and Process Skills (AMPS). Eight girls and 23 boys from Korea, with developmental disabilities and from 3 to 10 years of age participated in this study. Each child participated in 20 to 24 sessions of client-centred occupational therapy. Both the COPM and the AMPS change scores demonstrated statistically significant improvement (p < 0.01) in occupational performance. Significant correlations were found between COPM - Performance and AMPS - Motor skills (r(s) = 0.64, p < 0.05), and COPM - Satisfaction and AMPS - Process skills (r(s) = 0.62, p < 0.05) in a group positive towards client-centred occupational therapy. The COPM was a valuable tool in guiding and measuring the client-centred occupational therapy for children with developmental disabilities. The small sample size of 31 children limits the generalizability of the study's results. Future research needs to use a larger and more diverse sample of children to further validate the effectiveness of client-centred occupational therapy.

Effects of the Schroth exercise on idiopathic scoliosis: a meta-analysis.

INTRODUCTION: The purpose of this study was to examine the effects of the Schroth exercise on idiopathic scoliosis. The overall effect size was analyzed in 15 primary studies and a subgroup analysis of the standardized mean differences of effect sizes from 15 primary studies was also conducted. EVIDENCE ACQUISITION: We used PUBMED, MEDLINE, NDSL, EMBASE, and Web of Science. The key terms used in these searches were "Schroth," "scoliosis-specific exercise," "scoliosis," and "idiopathic scoliosis." EVIDENCE SYNTHESIS: Cobb's angle, asymmetry, angle of trunk rotation (ATR), strength of back extensor, strength of trunk flexor, quality of life (QOL), balance, chest expansion, and pulmonary function were coded as outcome measures for computing effect sizes. Potential moderating variables of the Schroth exercise included: 1) pre-intervention severity of the scoliosis; 2) duration; and 3) specific types of Schroth exercise. CONCLUSIONS: The overall effect size of the Schroth exercise is high (g=0.724). In addition, Schroth exercise may be more beneficial for scoliosis patients who have a 10 to 30° Cobb's angle than for those with a greater than 30° Cobb's angle. Patients should practice the exercise for at least one month to have a better effect. Thus, therapists should consider patients' initial curve status and exercise duration before prescribing the Schroth exercise program. Core muscle strength was most influenced, and structural deformity also changed after the Schroth exercise. In sum, the Schroth exercise is a recommended treatment method for scoliosis patients.

Event-related Desynchronization of Mu Rhythms During Concentric and Eccentric Contractions.

The purpose of this study was to compare the electroencephalographic (EEG) patterns and reaction times (RTs) of muscle activation between concentric and eccentric biceps brachii contractions under the RT paradigm and to evaluate how the EEG patterns and RTs changed with practice. Sixteen subjects performed 3 sets of 30 repetitions of submaximal voluntary concentric and eccentric biceps contractions. RT, event-related desynchronization (ERD) patterns of mu rhythm onset, and ERD amplitudes were selectively analyzed. Mental demand decreased as familiarity with the motor action increased due to practice regardless of contraction type. However, the 2 types of muscle contractions still have differences in brain activity regardless of decreased mental demand: eccentric contractions require earlier preparation than concentric contractions.

Predictors of dysfunction and health-related quality of life in the flexion pattern subgroup of patients with chronic lower back pain: The STROBE study.

Findings about predictors of chronic lower-back pain (CLBP) were inconsistent and inconclusive in previous studies because patients with CLBP are heterogeneous. Subgrouping patients with CLBP, according to a CLBP classification system, might thus clarify the research findings. CLBP in the direction of lumbar flexion movement, that is, the flexion pattern, is common in clinical situations. Therefore, the purpose of this study was to determine the predictors of dysfunction (pain, disability) and health-related quality of life in the flexion pattern subgroup of patients with CLBP.A cross-sectional study of prospectively collected data. One hundred eight subjects in the flexion pattern subgroup of CLBP. Thirteen variables were measured: the visual analog scale (VAS), the Oswestry Disability Index (ODI), the Short Form-36 (SF-36), the Beck Depression Inventory (BDI), hip internal rotation range of motion, hip flexion range of motion, knee extension range of motion, knee extension with dorsiflexion range of motion, ratio forward flexion, knee extension strength, hip extension strength, hip flexion strength, and lumbopelvic stability.The models for predictors of lower-back pain in the CLBP flexion pattern subgroup included knee extension and the BDI as predictor variables that accounted for 8.1% of the variance in the VAS (P < .05); predictors for disability included the BDI, age, and hip flexion strength, which accounted for 21.2% of the variance in the ODI (P < .05); predictors for health-related quality of life included the BDI, sex, knee extension with dorsiflexion range of motion, and age, which accounted for 38.8% of the variance in the SF-36 (P < .05) in multiple regression models with a stepwise selection procedure.The current results suggest that knee extension, the BDI, age, hip flexion strength, knee extension with dorsiflexion, and sex should be considered when determining appropriate prediction, prevention, and intervention in the flexion pattern subgroup of patients with CLBP.

Abdominal draw-in maneuver combined with simulated weight bearing increases transversus abdominis and internal oblique thickness.

The abdominal draw-in maneuver (ADIM) is a method commonly used to reestablish neuromuscular control of the deep spine muscles among individuals with musculoskeletal problems. The purpose of this study was to evaluate the effect of ADIM combined with simulated weight-bearing (SWB) activities in the facilitation of the deep spine muscles. The subjects were 30 young healthy individuals. Ultrasound images were used to measure the relative changes in transverse abdominal (TrA), internal oblique (IO) and external oblique (EO) muscle thickness during a simulated weight-bearing ADIM (SWB-ADIM). A paired t-test was used to determine the differences between the ADIM and SWB-ADIM conditions. The results showed that the thickness of the TrA and IO muscles in the SWB-ADIM condition was significantly higher than in the ADIM-alone condition. Our findings suggest that SWB-ADIM is more effective than ADIM alone for improving the deep spine muscles in real-life situations.

The effects of smart phone gaming duration on muscle activation and spinal posture: Pilot study.

This study investigates changes in the posture angles of the neck and trunk, together with changes in the muscle activation of users, at the start of and at 5, 10, and 15 minutes of smartphone use. Eighteen males participated in this study. Surface electromyography (EMG) and a digital camera were used to measure the muscle activation and angular changes of the neck and trunk of participants during smartphone use for a period of 16 minutes. Neck and trunk flexion significantly increased at 5, 10, and 15 minutes (p < 0.05) in comparison with the neck and trunk flexion of participants at the start of smartphone usage. The EMG activation and 10th%amplitude probability distribution function (APDF) values of the bilateral cervical erector spinae at 5-6, 10-11, and 15-16 minutes of usage (p < 0.05) were also significantly greater than at the start of usage. The EMG activation of the bilateral thoracic erector spinae and lower trapezius was significantly decreased at 5-6, 10-11, and 15-16 minutes of usage (p < 0.05). Smartphone use induced more flexed posture on the neck and trunk than other visual display terminal (VDT) work. Smartphone use also changed posture and muscle activation within a relatively short amount of time, just 5 minutes. Pain after 16 minutes of smartphone use was also observed. Thus, clinicians should consider the influences of smartphone use in posture and muscle activity in evaluation, intervention, and prevention of neck and trunk conditions.

Predictors of upper trapezius pain with myofascial trigger points in food service workers: The STROBE study.

Shoulder pain occurs commonly in food service workers (FSWs) who repetitively perform motions of the upper limbs. Myofascial trigger points (MTrPs) on the upper trapezius (UT) are among the most common musculoskeletal shoulder pain syndromes. This study determined the psychological, posture, mobility, and strength factors associated with pain severity in FSWs with UT pain due to MTrPs.In this cross-sectional study, we measured 17 variables in 163 FSWs with UT pain due to MTrPs: a visual analog scale (VAS) pain score, age, sex, Borg rating of perceived exertion (BRPE) scale, beck depression inventory, forward head posture angle, rounded shoulder angle (RSA), shoulder slope angle, scapular downward rotation ratio, cervical lateral-bending side difference angle, cervical rotation side difference angle, glenohumeral internal rotation angle, shoulder horizontal adduction angle, serratus anterior (SA) strength, lower trapezius (LT) strength, bicep strength, and glenohumeral external rotator strength, in 163 FSWs with UT pain due to MTrPs.The model for factors influencing UT pain with MTrPs included SA strength, age, BRPE, LT strength, and RSA as predictor variables that accounted for 68.7% of the variance in VAS (P < .001) in multiple regression models with a stepwise selection procedure. The following were independent variables influencing the VAS in the order of standardized coefficients: SA strength (ß = -0.380), age (ß = 0.287), BRPE (ß = 0.239), LT strength (ß = -0.195), and RSA (ß = 0.125).SA strength, age, BRPE, LT strength, and RSA variables should be considered when evaluating and intervening in UT pain with MTrPs in FSWs.