Background Slump sitting is a common posture in workplaces. There is limited evidence that poor posture impacts the mental state. This study aims to investigate whether slump posture results in more mental fatigue during computer typing, compared with normal posture and also to compare the effectiveness of stretching exercises with tDCS in fatigue monitoring. Methods The sample size for this study is set at 36 participants with slump posture and 36 participants with normal posture. In the first step, to find out the differences between normal and poor posture, they will be asked to perform the typewriting task for 60 min. During the first and last 3 min of typing, mental fatigue as the primary outcome using EEG signals and further measures including kinematic behavior of neck, visual analog fatigue scale, and musculoskeletal discomfort will be assessed. Post-experiment task performance will be calculated based on typing speed and typing errors. In the next step, to compare the effect of tDCS and stretching exercises on the outcome measures, the slump posture group will receive these interventions in two separate sessions before the typing task. Discussion With the assumption of showing significant differences in terms of outcome measures between slump and normal posture groups and also by showing the possible changes of the measures, by using either tDCS as a central modality or stretching exercises as a peripheral modality; the findings may provide evidence to indicate that poor posture has adverse effect on mental state and to introduce the effective method to overcome mental fatigue and promote work productivity. Trial registration Registered on the Iranian Registry of Clinical Trials on 21 September 2022, IRCT Identifier: IRCT20161026030516N2.

Background The Lumbar Spine Instability Questionnaire (LSIQ) is a self-reported measure of clinical instability of the lumbar spine. This study aimed to translate and culturally adapt the LSIQ into Persian language (LSIQ-P) and to evaluate its reliability and validity in a sample of patients with chronic non-specific low back pain (LBP). Methods In a cross-sectional study, the LSIQ was translated using guidelines. Participants with chronic non-specific LBP, aged ≥ 18 years old, answered an online survey consisting of LSIQ-P, the Persian Functional Rating Index (FRI), and the pain Numeric Rating Scale (NRS). Construct validity, internal consistency reliability, test–retest reliability, standard error of measurement (SEM), smallest detectable change (SDC), discriminant validity, and factor analysis were evaluated. Results The LSIQ was successfully adapted into Persian. A sample of 100 participants with LBP and 100 healthy subjects completed the survey. Floor and ceiling effects were not observed. Cronbach’s alpha = 0.767 and ICCagreement = 0.78 indicated good internal consistency and test–retest reliability. The SEM and SDC were 1.53 and 4.24, respectively. Construct validity of LSIQ-P was confirmed with significant correlation with Persian FRI (r = 0.44, p < 0.001) and pain NRS (r = 0.30, p = 0.003). An evidence of discriminant validity was demonstrated by significant difference in LSIQ-P total scores between the patients with LBP and healthy subjects, and between the patients with high total score ≥ 9 and those with low total score < 9 on the LSIQ-P. The LSIQ-P was found a multidimensional instrument with eight items appeared being redundant. Conclusions The Persian LSIQ showed satisfactory metric characteristics of reliability and validity. Further studies are required to elucidate the internal structure of the LSIQ-P.

Background Slumped sitting is a common poor posture which may cause mental fatigue and some disturbances in social activity. The management of slump posture often focuses on some biomechanical recommendations. To date, almost limited studies have explored the non-biomechanical factors such as the central component including mental fatigue of poor posture. Therefore, utilizing the quantitative electroencephalography (QEEG) to find out the changes after a prolonged repetitive task might be considered as a tool for tracking the central part in poor posture individuals. Accordingly, this study was designed to find out the differences of EEG parameters between normal and poor posture individuals; also, in the second step, to explore the effect of stretching exercises and tDCS to monitor the mentioned parameters during a continuous activity of typing in subjects with slump posture. Methods A sample of 60 volunteers will participate in this study and they will be assigned to two equal groups of people with normal and slump postures. In the first and last 3 minutes of 60 minutes of continuous typing, these people will be assessed for outcome measures of mental fatigue through QEEG and visual analog fatigue scale, the typing performances (i.e. speed and errors of typing), musculoskeletal discomfort and kinematic behavior of neck. Furthermore, the effects of stretching exercises and transcortical stimulation on the outcome measures in slump posture group will be evaluated. Discussion With the assumption of providing individuals' differences in terms of outcome measures in normal and slump posture and also by showing the possible changes of the measures, due to either tDCS as a central modality or stretching exercises as a peripheral modality; we might conclude that first, a central component is critical for evaluation in poor posture and second, may provide evidence to introduce the effective method to overcome mental fatigue and promote work productivity. Trial registration Registered on the Iranian Registry of Clinical Trials on 21 September 2022, IRCT Identifier: IRCT20161026030516N2