Objective: To estimate the possible associations between posture and physical activity (PA). Design: A systematic review and meta-analysis. Data sources: The search was conducted in seven databases (PubMed, Web of Science, SportDiscus, EMBASE, Scopus, Cochrane Library, and CINAHL) for studies published from inception to January 2023. Eligibility criteria for selecting studies: Studies were required to meet following criteria: (1) study design: cross-sectional, case control and cohort studies. (2) Participants: people of all ages without any diagnosed diseases. (3) Exposure and outcome: studies that examined the possible effect or correlations between PA, physical inactivity, physical exertion and human body posture. Results: Sixteen cross-sectional studies, two cohort studies and one case control study involving a total of 16772 participants aged from 6 to 79 years were included. Correlational studies showed that there was a significant relationship between PA and posture (C = 0.100, CI 95% = 0.012–0.186). However, regression studies demonstrated that there was not a significant association between PA and posture (C = 1.00, CI 95% = 0.998–1.002). Three studies investigated the association between PA and the lumbar lordosis and showed that there was not a significant association between the lordosis and PA (CI 95%: -0.253–0.048, P = 0.180). In addition, four studies showed that there were not any associations between scoliosis and PA (CI 95%: 0.819, 1.123, P = 0.607). The evidence of heterogeneity and publication bias was found among all analyzed data (P < 0.05). Also, meta regression was used for age and BMI and the results were not significant. Conclusion: Although a weak correlation was shown to exist between PA and human posture, the odds ratio indicated that there was not a significant association between PA and human posture. The lack of a significant relationship may indicate that multiple biopsychosocial factors may be involved in human posture. In summary, our study highlights the need for caution when interpreting the results of meta-analyses, particularly when there is significant heterogeneity and publication bias in the included studies.

Objective: Osteoarthritis (OA) of the knee is one of the most common global joint disorders, especially in aging population, and is among leading health-related concerns of societies. Therefore, this systematic review and meta-analysis was done to investigate the results related to the effects of exercise interventions on knee repositioning sense in patients with knee OA. Methods: An extensive search was independently performed in electronic databases including PubMed, MEDLINE, Web of Science, SCOPUS, and Google Scholar, to identify randomized clinical trials (RCTs) conducted on knee OA and to evaluate knee repositioning sense before and after different exercise interventions. After extracting relevant data from eligible studies, results of the studies were pooled using a random-effects model of meta-analysis. The Physiotherapy Evidence Database (PEDro) of clinical trials was used for quality assessment of eligible studies. Results: Among 2702 studies identified in the initial search, 17 studies were eligible for final systematic review and meta-analysis. The results showed that the patients who participated in different exercise interventions had significantly less knee repositioning error (mean differences: -1.141 degrees (95%CI: -1.510, -0.772, P < .001) compared to those who did not undergo exercise interventions. The eligible studies exhibited publication bias (Intercept: -6.69, P = .002), and the data showed significant heterogeneity (I2 = 85.633%, Q = 153.125, P < .001). Moreover, meta regression showed more prolonged exercise duration might have more effects on knee repositioning error (Coefficient=-0.860, 95% CI=-1.705, -0.016, Z=-2.00, P = .045). Conclusion: There is strong evidence that exercise interventions may effectively reduce knee repositioning error. Moreover, it seems that more prolonged exercise duration may be associated with the greater effect size.

Proper posture is essential for healthy living. Maintaining an ideal upright posture is one of the most critical indicators of the health of the musculoskeletal and movement systems. The current study compared the effectiveness of 6 weeks of NASM-based exercise training and eccentric-based exercise programs on body image and upper-quarter posture in schoolgirls with hyperkyphosis. In this randomized, controlled study, two intervention groups that received 6 weeks of NASM and eccentric-based exercise were compared with a control group that did nothing but continue their daily activities. For the purpose of conducting the experiment, 14 subjects were assigned to two groups (eccentric-based and control), and 12 subjects were assigned to the NASM group by using a simple blocked randomization method. The body esteem scale questionnaire was used to assess participants’ body image in the groups. Likewise, the photogrammetric technique and Kyphometer were used to gather data from all groups before and after six weeks of targeted corrective exercises. Differences in responses to workouts across groups were investigated using analysis of variance-covariance (ANCOVA) followed by post hoc Bonferroni tests. The results from the ANCOVA analysis indicated significant differences between the experimental and control groups regarding the effects of time*group on kyphosis (P < 0.001), shoulder angle (P < 0.001), and forward head posture (P < 0.001). Nonetheless, there was no significant difference between the considered groups regarding body image (P = 0.617). Based on the Bonferroni test, we found a significant difference between the control and eccentric-based groups for postural parameters measured during the study (P < 0.001). Similarly, both the control and NASM groups demonstrated significant differences for all variables(P < 0.001), except the body image. However, we could not find any statistical difference between the NASM training group and the eccentric-based exercise group concerning the upper quarter postural variables that were mentioned before. This study demonstrates that compared with a control group, schoolgirls with hyper-kyphosis who received a six-week intervention of eccentric-based and NASM- based exercises had significantly improved postural parameters but not body image. Despite these advantages, the improved kyphosis, shoulder angle, and forward head posture did not differ significantly between the NASM-based and eccentric-based exercise groups.

Most sports and leisure activities involve repetitive movements in the upper limb, which are typically linked to pain and discomfort in the neck and shoulder area. Movement variability is generally expressed by changes in movement parameters from one movement to another and is a time-dependent feature of repetitive activities. The purpose of this study was to examine the effect of repeated movement-induced fatigue on biomechanical coordination and variability in athletes with and without chronic shoulder pain (CSP). In this controlled laboratory study, 24 overhead athletes in two groups of athletes with (N = 12) and without (N = 12) CSP were recruited. Biomechanical and Electromyographical data were recorded while the athletes were asked to perform repeating reaching tasks (RRT). Kinematic data was recorded every 30 s of the minutes of the repetitive pointing task (RPT). The kinematic and electromyography data were recorded at the first 30 s of “Fatigue-Terminal” (FT) and the last 30 s of “No-Fatigue” (NF) in the repetitive pointing task (RPT). Raw data was analyzed by using MATLAB code to extract the relevant coordination and movement variability data. Different fatigue conditions led to significant kinematic changes during the repetitive pointing task. In the CSP group, trunk lateral flexion decreased after fatigue, while it increased in the CON group (p < 0.013). Trunk rotation and shoulder elevation angles were smaller before fatigue than after in both groups (p < 0.001). Variability in joint angles, including trunk lateral flexion and elbow flexion, increased after fatigue, indicating less stability in movement patterns (p < 0.001). The coordination between trunk movement and shoulder elevation was altered post-fatigue, with significant changes in EMG variability for muscles like the Lower Trapezius and Long Head of the Biceps (p < 0.001). Results of our study indicate that both groups were able to accomplish fatigue, but they employed different movement strategies. The CSP group primarily focused on controlling the shoulder joint, while the CON group utilized both the shoulder and elbow joints in their strategy. This difference suggests that individuals in the CSP group who experienced chronic pain may have developed a strategy to minimize pain and fatigue during the task. Specifically, the CSP group’s approach appeared to involve adjustments in movement patterns to manage the task despite fatigue. This adaptation contrasts with the CON group’s more complex movement strategy, which involved greater variability and adjustments in both the shoulder and elbow joints.

Scapulothoracic motion during arm elevation involves scapular posterior tilt (PT), upward rotation (UR), and external rotation (ER). Abnormal scapular kinematics are common in people with chronic shoulder pain, potentially exacerbating symptoms and impairing function. Push-ups, a common exercise for shoulder rehabilitation, may influence scapular motion but have not been extensively studied in this context. Thus, this study aimed to investigate the effect of hand position on scapular kinematics during a push-up exercise in athletes with and without chronic shoulder pain (CSP). Twenty-four male overhead athletes were allocated into two groups: CSP (n = 12) and Control (CON; n = 12). Scapular kinematics in three planes (PT, UR, and ER) were measured using a Vicon motion capture system during push-ups in three hand positions (internal rotation, IR; neutral rotation, NR; and external rotation, ER). Measurements were taken in the concentric phase of the push-up. Statistical analyses using repeated-measures ANOVA assessed the effects of hand position and elbow extension on scapular kinematics between the two groups. For PT of the scapula, in the IR hand position, participants from both the CON and CSP groups showed similar decreases (CON group = from 25.74° to -16.10°; P < 0.001). In the NR hand condition, the CON group decreased PT from 16.12° to -15.98° (P < 0.001), but there was no significant change in the CSP group. In the ER hand condition, for the CON group, PT decreased from 18.63° to -9.38° (P < 0.026), with no significant change observed in the CSP group. For UR of the scapula, the CON group showed significant decreases in the IR hand condition (from 15.37° to -2.28°; P < 0.019), while the CSP showed minimal changes. In the IR hand condition, the ER of the scapula increased from 20.44° to 25.13° (P < 0.003) in the CON group. At the same time, the CSP showed smaller changes. In the NR hand condition, ER of the scapula in the CON group decreased from 24.79° to 9.38° (P < 0.001), with no significant change observed in the CSP group. Scapular kinematics (UR, PT, and ER) differed significantly across hand rotation conditions and groups. The CON group exhibited more pronounced changes in these kinematic measures, while the CSP group showed limited variation. This may indicate an association between chronic pain and movement restriction. These findings emphasize the need for targeted rehabilitation strategies that consider these kinematic differences.