Search

Background: Lower limb strength is crucial for stability and functional movement, such as walking, running, squatting, and balance, with the gluteus maximus (Gmax) being pivotal. Squat exercises are commonly used to strengthen the Gmax; however, the impact of ankle position on muscle activation during squats is not well understood. Objects: This study examined Gmax and lower limb muscle activation patterns in three ankle positions during squats, aiming to optimize rehabilitation strategies and enhance exercise prescriptions. Methods: Surface electromyography recorded the activation levels of the Gmax, vastus medialis oblique (VMO), vastus lateralis oblique (VLO), and biceps femoris (BF) across three ankle positions: neutral (NEU), dorsiflexion (DF), and plantarflexion (PF). A repeated-measures design was employed, involving 30 healthy adults (26 males and 4 females) aged 18–30 years. Muscle activation patterns were statistically analyzed to identify significant variations across these conditions, with the significance level set at p < 0.05. Results: During squats, DF of the ankle joint significantly increased Gmax activation compared with PF and NEU positions, indicating that an ankle position closer to DF may enhance hip extension. In contrast, PF was associated with heightened activation of the VMO and VLO, suggesting that this position may be beneficial for exercises focusing on knee stability. No significant changes were observed in the BF activation across the ankle positions, indicative of its limited involvement in response to variations in ankle positioning. Conclusion: These results underscore the importance of ankle joint positioning in modulating lower-limb muscle engagement during squatting. Ankle DF may be recommended to maximize Gmax activation, which is beneficial for hip-focused strengthening, whereas PF may supports knee stability by targeting quadriceps activation. This study provides evidence for adjusting ankle positioning during squat exercises to optimize specific rehabilitation and performance outcomes.

Background: In modern society, the use of computers accounts for a large proportion of our daily lives. Although substantial research is being actively conducted on musculoskeletal diseases resulting from computer use, there has been a recent surge in interest in improving the working environment for prevention. Objects: This study aimed to examine the effects of posture correction feedback (PCF) on changes in neck posture and muscle activation during computer typing. Methods: The participants performed a computer typing task in two sessions, each lasting 16 minutes. The participant’s dominant side was photographed and analyzed using ImageJ software to verify neck posture. Surface electromyography (EMG) was used to confirm the participant’s cervical erector spinae (CES) and upper trapezius muscle activities. The EMG signal was analyzed using the percentage of reference voluntary contraction and amplitude probability distribution function (APDF). In the second session, visual and auditory feedback for posture correction was provided if the neck was flexed by more than 15° in the initial position during computer typing. A 20-minute rest period was provided between the two sessions. Results: The neck angle (p = 0.014), CES muscle activity (p = 0.008), and APDF (p = 0.015) showed significant differences depending on the presence of the PCF. Furthermore, significant differences were observed regarding the CES muscle activity (p = 0.001) and APDF (p = 0.002) over time. Conclusion: Our study showed that the feedback system can correct poor posture and reduces unnecessary muscle activation during computer work. The improved neck posture and reduced CES muscle activity observed in this study suggest that neck pain can be prevented. Based on these results, we suggest that the PCF system can be used to prevent neck pain.

Background: Despite the fact that aquatic exercise is one of the most popular alternative treatment methods for children with cerebral palsy (CP), there are few research regarding its effectiveness. Objects: The purpose of this study was to examine the effects of aquatic exercise on upper extremity function and postural control during reaching in children with CP. Methods: Ten participants (eight males and two females; 4–10 years; Gross Motor Function Classification System levels II–IV) with spastic diplegia were recruited to this study. The aquatic exercise program consisted of four modified movements that were selected from the Halliwick 10-point program to enhance upper extremity and trunk movements. The participants attended treatment two times a week for 6 weeks, averaging 35 minutes each session. The Box and Block Test (BBT), transferring pennies in the Bruininks-Oseretsky Test (BOT), and pediatric reaching test (PRT) scores were used as clinical measures. Three-dimensional motion analysis system was used to collect and analyze kinematic data. Differences in BBT and BOT values among pre-treatment, post-treatment, and retention (after 3 weeks) were analyzed using a Friedman test. In addition, the PRT scores and variables (movement time, hand velocity, straightness ratio, and number of movement units) from the three-dimensional motion analysis were tested using a Wilcoxon signed-rank test. The significance level was established at p < 0.05. When the results appeared to be statistically significant, a post-hoc test for multiple comparisons was performed with the Wilcoxon signed-rank test. Results: All clinical measures, which included BBT, transferring pennies of BOT, and PRT, were significantly increased between pre-intervention and post-intervention scores and between pre-intervention and retention scores after treatment (p = 0.001). Three-dimensional motion analysis mostly were significantly improved after treatment (p = 0.001). Conclusion: Aquatic exercise may help to improve body function, activity, and participation in children with varying types of physical disabilities.