Earticle

The purpose of this study was to learning the effects of sitting posture on lung capacity. Subjects were 45 healthy adults and center of pressure, forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and FEV1/FVC were measured. FVC and FEV1 were significantly high in the order of short lordosis posture, normal posture, and slumped posture. Lung capacity reduced the most with slumped posture. When exercising in sitting posture, it will be effective to inform patients about keeping a normal posture or short lordosis posture using lumbar support.

본 연구의 목적은 룸바 쿠카라차 동작 시 트윈 바가 발의 압력분포 및 자세에 미치는 영향을 규명하는데 있다. 연구 대상자로는 댄스스포츠 전문기관에서 훈련받고 있는 10대 ~ 40대 사이의 자원한 남녀 30명이다. 독립변인은 바의 수로 구분하였고, 종속변인은 압력분포 및 자세이다. 또한 연습하는 동안 안정감과 부담감을 알아보기 위하여 설문지 조사를 하였다. 측정치는 SPSS 23.0을 활용하여 대응표본 t 검증(Paired sample t-test)을 분석하였으며, 이에 따른 결과는 다음과 같다. 첫째, 트윈 바를 사용하였을 때, 양 발바닥의 중앙에서부터 압력 중심 이동 곡선이 시작하였고, 좌우(X), 전후(Y) 방향으로의 이동 길이가 길어졌다. 그리고 양 발바닥의 압력 중심 이동 곡선의 좌우, 전후 불균형이 완화되었다. 둘째, 압력분포 변인의 결과를 종합하였을 때, 원 바를 사용할 때는 첫 번째 발가락의 압력이 높았으나, 트윈 바를 사용할 때는 네 번째, 다섯 번째 발가락의 압력이 높았다. 셋째, 트윈 바를 사용하였을 때, 어깨와 골반의 수평 경사각이 유의하게 증가하였고, 자세의 편측성이 완화되었다. 넷째, 룸바 쿠카라차 동작 시 바의 수에 따라 피험자들이 느끼는 안정감과 부담감은 유의한 차이가 있었다. 결론적으로, 룸바 쿠카라차 동작 시 트윈 바를 사용하는 것은 좌우․전후 대칭적인 동작으로 교정하고, 관절 움직임의 범위를 증가시켜 동작 완성도에 도움을 주었다. 또한 발가락 외측 부분의 사용을 도모하여 내측 족궁의 무너짐은 물론이고 무지외반증을 예방해주는 기능을 하였다. 이러한 결과는 발 변형을 예방하고 동작의 숙련도를 향상시킬 수 있는 훈련방법을 제시한 것으로 의의가 있다고 할 수 있다. 또한 발바닥 부위별 압력 분포 결과는 댄스스포츠화를 개발하는 기초자료로 유용할 것이다.

The purpose of the study is to reveal the effect of the number of bar on foot pressure distribution and posture when practicing cucarachas. The subjects of this study consisted of 30 male and female volunteers enrolled in professional dance sports institution. Independent variables were the number of bar (one or two). Dependent variables were foot pressure distribution and posture. Questionnaire was used to analyze comfort and discomfort during practicing. In accordance with a result, first, the length of changes of central movement of X and Y increased when using the twin bar. These changes appeared at the center of the foot and imbalance was alleviated than before. Second, the first toes had the highest value with the one bar. On the other hand, with the application of the twin bar, the fourth and fifth toes had the highest value with statistical significance. Third, when using the twin bar, the horizontal bank angle of shoulder and pelvis increased significantly and imbalance was alleviated than before. Lastly, there were statistically significant differences for comfort and discomfort depending on the number of bar. In conclusion, practicing method using twin bars corrected posture to have enhanced balance. The twin bar also increased the range of motion of the joints so that it could improve movement performance. These results are meaningful in terms of suggesting educational methods to prevent deformity of foot and improve exercise ability.

본 연구는 머리 젖힘 각도의 변화에 따라 물 삼킴 시 목뿔위근육과 목뿔아래근육의 근 활성화 수준의 변화를 확인하였 다. 삼킴에 문제가 없는 건강한 성인 여성 여섯 명(모든 대상자의 연령: 21세)이 본 연구에 참여하였다. 대상자들이 3가지 자세 (바른 자세, 30도 머리 젖힘, 최대로 머리 젖힘)에서 3mL 물 삼킴 시 목뿔위근육과 목뿔아래근육의 활성도를 표면 근 전도를 이용하여 측정하였다. 30도 머리 젖힘과 완전 머리 젖힘 자세에서 물 삼킴 시 목뿔위근육의 활성도는 바른 자세에서 삼킴 시보다 각각 74.9%와 102.4%가 증가하였으나 차이는 통계적으로 유의하지 않았다 (p=0.046, 0.028). 30도 머리 젖힘과 완전 머리 젖힘 자세에서 물 삼킴 시 목뿔아래근육의 활성도 또한 바른 자세에서 삼킴 시보다 각각 32.6%와 47.2% 증가하였으나 차이는 통계적으로 유의하지 않았다 (p=0.028, 0.028). 목뿔위근육과 목뿔아래근육의 활성화 수준은 머리 젖힘 각도의 증가와 관련하여 증가하는 경향을 나타내었다. 이는 삼킴 관련 근육의 약화를 보이는 연하장애 환자들의 체계 적인 근력 강화 프로그램을 개발하는데 고려될 수 있을 것이다. 본 연구는 향후에 진행될 연구의 가능성과 방향을 확인하기 위하여 계획된 예비연구이다. 머리 젖힘 각도가 증가함에 따라 삼킴 관련 근육들의 활성화수준의 변화를 확인하기 위하여 보다 많은 인원을 대상으로 한 연구가 진행되어야 할 것이다.

This study investigated changes in the suprahyoid and infrahyoid muscle activation levels during water swallowing, according to the degree of head extension. Six healthy adult women who have no swallowing problems participated in this study. The subjects were instructed to swallow 3 mL of water in three positions (erect posture, 30ﾟ head extension, and full head extension). As they did, the activation levels of the suprahyoid and infrahyoid muscles were measured using surface electromyography. When swallowing water in 30ﾟ and full extended head positions, the activation level of the suprahyoid muscles increased by 74.9% and 102.4%, respectively, compared to the level when in erect posture. However, the difference was not statistically significant (p=0.046, 0.028). The activation levels of the infrahyoid muscle when swallowing water while in the 30ﾟ and fully extended head positions were also increased by 32.6% and 47.2%, respectively, compared to those when in the erect posture. However, the difference was also not statistically significant (p=0.028, 0.028). The activation levels of the suprahyoid and infrahyoid muscles tends to increase when swallowing with respect to head extension angle; this could be considered in developing a systematic muscle strengthening program for patients with conditions involving swallowing-related muscle weakness. This was a preliminary study aimed to confirm the possibility and direction of future studies. A larger sample group should be investigated to confirm the activation levels of swallowing-related muscles as the angle of head extension increases.

This study is based on the empirical knowledge in the field that junior elite players in the period of growth. In other words they had a good result in the muscular strength and power by heavy weight through the correct weight training action and posture correction improvement by bar training. The experiment participants of this study is all the junior elite players, they turned out to be the condition of uncorrect posture through the advance examination. In this condition, physical strength program for the muscular strength and power could bring an effect decrease and a injury doubling. Although the effect about the muscular strength and power advance was not made in this study, but a positive result in height and the vertabral alignment change appeared. So if we more attempt the revision of basic posture instead of the unvaried and hasty physical strength program, more effective muscular strength and power improvement could be expected.

Purpose: The purpose of this study was to evaluate the effects of a devised posture management program based on the Theory of Planned Behavior in adolescents with mild idiopathic scoliosis. Methods: A quasi-experimental study was conducted. It involved a nonequivalent comparison group design with pretest and posttest. Forty-four female adolescents with mild idiopathic scoliosis participated; data from 35 participants (20 for the test group, 15 for the control group) were used for the final analyses. The devised posture management program ran for 6 weeks. Posture management behavioral determinants (attitude, subjective norms, perceived behavioral control, and behavioral intention) as cognitive outcomes and muscular strength and flexibility as physical outcomes were measured three times: at baseline, week 6 and week 8. Cobb’s angle as another physical outcome was measured twice: at baseline and week 8. Descriptive analysis, repeated measures analysis of variance and t test were used for data analyses. Results: Attitude, perceived control, and behavioral intention were consistently enhanced by the posture management program. The intervention increased flexibility and muscular strength and decreased Cobb’s angle, which reduced spinal curvature. Frequency of posture management exercise showed a gradual increase in the test group. Conclusion: The results indicate that the posture management program is effective in maintaining posture management behavior in adolescents with mild idiopathic scoliosis for both cognitive and physical outcomes. The posture management program should be helpful in expanding the role of school nurses in improving the health status of adolescents with mild idiopathic scoliosis.

Objective: To evaluate the effectiveness of a squatting posture grading system established to screen for limited ankle dorsiflexion.Methods: The squat posture grading system categorizes subjects’ squat posture into three grades. Grade 1 is defined as being able to maintain a squatting posture with heels on the ground in full ankle dorsiflexion without effort. Grade 2 is defined as being able to perform the same position, but unable to maintain the position for more than 5 seconds or requiring trunk and leg muscle efforts to maintain the position. Grade 3 is defined as being unable to maintain the same position and falling backwards immediately if attempted to touch the ground with heels. Next, subjects’ ankle dorsiflexion angles were directly measured in knee flexed and extended position by goniometer.Results: Out of the 92 total subjects, 35 were in grade 1, 18 were in grade 2, and 39 were in grade 3. The average ankle dorsiflexion angle with knee flexed position were 23.13° for grade 1, 16.03° for grade 2, and 9.31° for grade 3. The average ankle dorsiflexion angle with knee extended position were 15.16° for grade 1, 7.92° for grade 2, and 3.40° for grade 3. Ankle dorsiflexion angles showed a significant decrease from grade 1 to 3 (p<0.05).Conclusion: The squatting posture grading system defined in this study effectively graded the subjects based on the difference in their average ankle dorsiflexion angle. This system could be used as a quick screening method for limited ankle dorsiflexion.

The surgical navigation system enhances surgical safety and accuracy by providing precise guidance. However, traditional pose estimation algorithms lack real-time performance and accuracy. To address this issue, a multi-average Long Short Term Memory (LSTM) prediction network is designed to maintain sensitivity in estimating the position of surgical instruments and track their random motion trends. Additionally, the spatial coordinates of positioning markers are applied back to the imaging plane, reducing the recognition range and improving algorithm running speed. Experimental results show that the average time of estimation is less than 1ms while ensuring the prediction effect.

Background The way the body is positioned during recumbent cycle exercise has a significant impact on exercise performance. This type of exercise not only improves cardiovascular endurance but also strengthens the lower limbs. Purpose This study aimed to investigate the impact of body posture during recumbent cycle exercise on the Peak Systolic Flow Velocity (PSV), Pulsatility Index (PI), and rate of perceived exertion (Borg scale) of the common carotid artery. Study design A pre-post cross-sectional design Methods The participants comprised 15 adults without a history of hyperlipidemia or coronary artery disease, who had not previously engaged in recumbent cycle exercise (mean age 22.9±2.0). Doppler ultrasonography was utilized to measure PSV and PI. Data analysis involved one-way repeated measures ANOVA (p<0.05), with post-hoc testing conducted using Bonferroni post hoc analysis (α=0.017). Results Three distinct body postures were assumed during the recumbent cycle exercise: sitting at a hip joint angle of 100° (100° Trunk posture; TP), leaning against the backrest at a hip joint angle of 130° (130° TP), and leaning against the backrest at a hip joint angle of 160° (160° TP). Statistically significant differences were observed in the mean values of PSV and Borg scale among the three postures (p<0.05), while no significant difference was noted in the mean PI values (p=0.533). Bonferroni post hoc analysis indicated significant differences in PSV between 100° TP and 160° TP (p=0.001) and between 130° TP and 160° TP (p=0.001), with no significant difference between 100° TP and 130° TP (p=0.729). Borg scale demonstrated significant differences between 100° TP and 160° TP (p=0.001) and between 130° TP and 160° TP (p=0.001), but no significant difference between 100° TP and 130° TP (p=0.626). Conclusions In conclusion, recumbent cycle exercise to enhance cerebral blood flow is recommended in the order of 160° TP, followed by 130° TP.

Background Obesity has been suggested as a social issue, but problems in the foot and ankle have not been clearly identified in people with obesity. Purpose To compare foot posture, joint position sense, dynamic balance ability, and plantar pressure in obesity group (OG) and normal weight group (NWG) Study design Cross-sectional study Methods This study included 52 adults (26 for OG and 26 for NWG). All subjects had their foot posture index-6 and joint position sense (20° of inversion, 20° of plantar flexion, 10° of eversion, and 10° of dorsiflexion) measured, as well as their dynamic balance ability using a dynamic balance test and plantar pressure of the medial forefoot during the dynamic balance test. These variables were compared between OG and NWG. Results OG showed significantly larger joint position sense error for eversion and increased plantar pressure of the medial forefoot during the dynamic balance test in the posteromedial direction. Significant differences were unobserved in other variables between the two groups. Conclusions Adults with obesity have deficits in joint position sense and increased plantar pressure of the medial forefoot.

Objective To investigate the correlation between the Foot Posture Index (FPI) (including talar head palpation, curvature at the lateral malleoli, inversion/eversion of the calcaneus, talonavicular bulging, congruence of the medical longitudinal arch, and abduction/adduction of the forefoot on the rare foot), plantar pressure distribution, and pediatric flatfoot radiographic findings. Methods Nineteen children with flatfoot (age, 9.32±2.67 years) were included as the study group. Eight segments of plantar pressure were measured with the GaitView platform pressure pad and the FPI was measured in children. The four angles were measured on foot radiographs. We analyzed the correlation between the FPI, plantar pressure characteristics, and the radiographic angles in children with flatfoot. Results The ratio of hallux segment pressure and the second through fifth toe segment pressure was correlated with the FPI (r=0.385, p=0.017). The FPI was correlated with the lateral talo-first metatarsal angle (r=0.422, p=0.008) and calcaneal pitch (r=?0.411, p=0.01). Conclusion Our results show a correlation between the FPI and plantar pressure. The FPI and pediatric flatfoot radiography are useful tools to evaluate pediatric flatfoot.

The Paris Agreement signatories have committed to limit global average temperature increase above pre-industrial levels to below 2℃. Reporting of the greenhouse gas (GHG) inventory is regulated by the United Nations Framework Convention on Climate Change. Currently, countries are transitioning from the Measurement, Reporting, and Verification reporting system to the Enhanced Transparency Framework (ETF) reporting system. Under the ETF, countries are required to use the 2006 guidelines (GL). This study explored how replacing the 1996 GL with the 2006 GL or the 2019 Refinement impacts the overall GHG inventory from the livestock sector, with Korea as a case study. The result affirmed that changes in guideline led to changes in total estimated emissions. Moving from the 1996 GL to the 2019 Refinement resulted in more significant differences in estimated emissions than moving to the 2006 GL in terms of source-based emissions, annual inventory, or trend. Notably, guidelines’ changes also impacted the proportion of each source’s contribution to total estimated emissions. While applying the most recent guidelines is expected to produce more accurate estimations, consistency with the previous inventory calculated with previously used guidelines should be maintained. Additionally, the changes in the contribution of each source clarifies that although enteric fermentation is the largest contributor of GHGs, relevant mitigations are likely less feasible compared to those related to manure management. This is because of naturally occurring biological processes. Thus, mitigations in manure management are suggested.

Objective To assess head posture using cervical spine X-rays to find out whether forward head posture is related to myofascial pain syndrome (MPS) in neck and shoulder.Methods Eighty-eight participants who were diagnosed with MPS in neck and shoulder were evaluated in this study. Four parameters (distance among head, cervical spines, and shoulder, and cervical angle) were measured from lateral view of cervical spine X-ray. The location and number of trigger points in the neck and shoulder and symptom duration were evaluated for each patient.Results Both horizontal distances between C1 vertebral body and C7 spinous process and between the earhole and C7 vertebral body were negatively correlated with cervical angle reflecting cervical lordosis (p<0.05). Younger patients had significantly (p<0.05) less cervical angle with more forward head posture. There was no relationship between MPS (presence, location, and number of trigger points) and radiologic assessments (distance parameters and the cervical angle). Conclusion Forward head posture and reduced cervical lordosis were seen more in younger patients with spontaneous neck pain. However, these abnormalities did not correlate with the location or the number of MPS. Further studies are needed to delineate the mechanism of neck pain in patients with forward head posture.

Objective To estimate the effects of a relatively protruded head and neck posture on postural balance, in computer based worker. Method Th irty participants, who work with computers for over 6 hrs per day (Group I), and thirty participants,who rarely work with computers (Group II), were enrolled. Th e head and neck posture was measured by estimating angles A and B. A being the angle between the tragus of the ear, the lateral canthus of the eye, and horizontal line and B the angle between the C7 spinous process, the tragus of the ear, and the horizontal line. Th e severity of head protrusion with neck extension was assessed by the subtraction of angle A from angle B. We also measured the center of gravity (COG) and postural balance by using computerized dynamic posturography to determine the eff ect of computer-based work on postural balance. Results Results indicated that group I had a relatively more protruded head with extensive neck posture (angle B-A of group I and group II, 28.2±8.3, 32.9±6.0; p<.05). Th e COG of group I tended more toward the anterior than that of group II. Postural imbalance and impaired ability to regulate movement in forward and backward direction were also found. Conclusion The results of this study suggest that forward head postures during computer-based work may contribute to some disturbance in the balance of healthy adults. These results could be applied to education programs regarding correct postures when working at a computer for extended periods of time.

Background Logistics service workers face elevated injury rates, with ankle-related incidents comprising 23% of workplace injuries. Traditional binary foot posture classifications may oversimplify the complex biomechanical relationships affecting dynamic balance performance in occupational settings. Purpose To apply unsupervised machine learning clustering to identify distinct foot posture phenotypes among logistics service workers and compare dynamic balance performance between identified clusters using the Y-Balance Test. Study design Cross-sectional observational study Methods A total of 112 logistics service workers were analyzed using K-means clustering based on age, body mass index, work duration, navicular drop, and resting calcaneal stance position. Silhouette score analysis determined optimal cluster number. Dynamic balance was assessed using the Y-Balance Test, measuring reach distances in anterior, posteromedial, and posterolateral directions. Results Four distinct phenotypes emerged: rearfoot valgus-dominant pronated (n=22), midfoot collapse-dominant pronated (n=32), age-related (n=23), and supinated (n=35) foot types. Significant differences in dynamic balance performance were observed in the posterolateral direction (F=3.900, p=0.011). The supinated phenotype demonstrated superior posterolateral reach performance (77.76±13.63%) compared to midfoot collapse-dominant (66.18±16.37%, p=0.003) and age-related phenotypes (67.78±14.97%, p=0.018). Conclusions Unsupervised machine learning successfully identified naturally occurring foot posture phenotypes with distinct dynamic balance characteristics. Midfoot collapse-dominant pronation demonstrated greater balance impairments than rearfoot valgus patterns, supporting the implementation of phenotype-specific interventions for workplace injury prevention in logistics workers.

Background Although high-quality biomechanical evaluations, such as a three-dimensional motion analysis and electromyography, have been performed to verify the relationship between forward head posture (FHP) and shoulder dysfunction, most of the studies have mainly focused on neck and shoulder muscle activity or neck pain. Purpose To investigate the effects of artificial FHP on internal and external rotator strength and range of motion (ROM) of the glenohumeral joint using a dynamometer and inclinometer. Study design The study had a repeated-measures design. Methods ROM and muscle strength data were obtained from 29 participants. A standard incli-nometer and dynamometer were used to measure passive shoulder rotation ROM and muscle strength, respectively. Repeated-measures analysis of variance was used to compare ROM and strength data of the shoulder joint with and without FHP conditions and both shoulder sides. Results There was a significant difference in external rotation ROM values during passive ROM examination in FHP compared to no FHP (p<0.05). The internal rotation ROM value differed significantly according to the shoulder side (p<0.05). There was a significant difference in external rotator maximal strength values between FHP and no FHP (p<0.05). However, the shoulder sides and interaction effects between FHP conditions and shoulder sides for any ROM rotation values were not significant (p>0.05). Conclusions The results of this study indicated that FHP had a negative effect on rotation ROM and muscle strength of the shoulder joint, implying that it may act as a factor causing musculo-skeletal problems in the neck and shoulder region. Therefore, maintaining the correct head posture is important not only for intact of the neck but also for the health of the shoulder joint.

Objective To evaluate the risk of phrenic nerve injury during ultrasound-guided stellate ganglion block (US-SGB) according to sonoanatomy of the phrenic nerve, and determine a safer posture for needle insertion by assessing its relationship with surrounding structure according to positional change.Methods Twenty-nine healthy volunteers were recruited and underwent ultrasound in two postures, i.e., supine position with the neck extension and head rotation, and lateral decubitus position. The transducer was placed at the anterior tubercle of the C6 level to identify phrenic nerve. The cross-sectional area (CSA), depth from skin, distance between phrenic nerve and anterior tubercle of C6 transverse process, and the angle formed by anterior tubercle, posterior tubercle and phrenic nerve were measured.Results The phrenic nerve was clearly identified in the intermuscular fascia layer between the anterior scalene and sternocleidomastoid muscles. The distance between the phrenic nerve and anterior tubercle was 10.33±3.20 mm with the supine position and 9.20±3.31 mm with the lateral decubitus position, respectively. The mean CSA and skin depth of phrenic nerve were not statistically different between the two positions. The angle with the supine position was 48.37o±27.43o, and 58.89o±30.02o with the lateral decubitus position. The difference of angle between the two positions was statistically significant.Conclusion Ultrasound is a useful tool for assessing the phrenic nerve and its anatomical relation with other cervical structures. In addition, lateral decubitus position seems to be safer by providing wider angle for needle insertion than the supine position in US-SGB.

Background Many people do not know they have scapular downward rotation syndrome (SDRS) because they have no pain. However, SDRS may cause secondary issues such as neck pain, shoulder instability, and rotator cuff injury. Thus, individuals with SDRS should perform exercises that are suitable for SDRS. Purpose The purpose of this study was to compare the muscle activity of the pectoralis major (PM) and the serratus anterior (SA) during shoulder-strengthening exercises in the side-lying position, standing position, and supine position using an elastic band to suggest an effective exercise posture for SDRS. Study design Comparative, repeated measures design Methods The subjects were thirty-nine adults with SDRS aged 25 to 40 years old were participated. We conducted a repeated measures analysis of variance by measuring muscle activities in SA, PM, while performing shoulder-strengthening exercises using an elastic band in three postures (side-lying, standing, and supine positions) in random order, using a surface electromyography device. One-way repeated measures analysis of the variance and a Bonferroni post hoc test were used. Results The SA had the highest muscle activity in the order of side-lying position, standing position, and supine position, while the PM had low muscle activity in the side-lying position, supine position, and standing position in that order. Conclusions The SA-intensive strengthening exercise for SDRD using an elastic band in the side-lying position was selected as the appropriate exercise.

Objective: To assess postural stability, specifically center of body sway during single-leg standing balance, among individuals with and without forward head posture (FHP) during smartphone use. Methods: The research recruited 53 healthy smartphone users, aged 18?25, and categorized them into FHP group comprising 26 subjects and the normal (control) group with 27 subjects. Participants were assigned the task of maintaining balance while engaged in smartphone typing during single-leg standing. The experiment involved four specific conditions according to neck posture and stable of surface. The study meticulously quantified body center of pressure (COP) sway amplitudes using the Nintendo Wii Balance Board. Results: The research revealed that individuals with FHP exhibited significantly greater body sway compared to the control group when using smartphones. Notably, distinct variations were observed in path length sway, anteroposterior (AP), and mediolateral (ML) sway amplitude, particularly evident when maintaining flexed neck positions on a soft surface while engaged with smartphones. Conclusion: These findings strongly suggest that individuals with FHP encounter deteriorated postural stability during smartphone use, particularly in challenging head positions.

Objective To investigate the differences in hyolaryngeal kinematics at rest and during swallowing in the upright sitting (UP) and the lateral decubitus (LD) postures in healthy adults, and delineating any potential advantages of swallowing while in the LD posture.Methods Swallowing was videofluoroscopically evaluated in 20 healthy volunteers in UP and LD postures, based on the movements of hyoid bone, vocal folds, and the bolus head. Parameters included the Penetration-Aspiration Scale (PAS), horizontal and vertical displacement, horizontal and vertical initial position, horizontal and vertical peak position, time to peak position of the hyoid bone and vocal folds, and pharyngeal transit time (PTT). Results Nine participants were rated PAS 2 in the UP and 1 was rated PAS 2 in the LD (p=0.003) at least 1 out of 3 swallows each posture. The hyoid and vocal folds showed more anterior and superior peak and initial positions in the LD. In addition, swallowing resulted in greater vertical and smaller horizontal displacement of the hyoid in LD posture compared with UP. Time to peak position of the hyoid was shorter in LD. The maximal vertical and horizontal displacement of the vocal folds, and PTT were comparable between postures. Conclusion The results showed that the peak and initial positions of the hyoid and larynx and the pattern of hyoid movement varied significantly depending on the body postures. This study suggests that the LD posture was one of the safe feeding postures without any increased risk compared with UP posture.

Objective To compare quantitative muscle activation between erect and slouched sitting postures in the muscles around the scapula, and to investigate the correlation between the angle of thoracic kyphosis and the alteration of muscle activity depending on two different sitting postures.Methods Ten healthy males participated in the study. Unilateral surface electromyography (SEMG) was performed for serratus anterior, middle trapezius (MT), and lower trapezius (LT), which are scapular stabilizer muscles, as well as latissimus dorsi. Participants elevated their shoulders for 3 seconds up to 90o abduction in the scapular plane, tilting 30o anterior in the coronal plane. They were told to hold the position for 10 seconds and voluntary isometric contractions were recorded by SEMG. These movement procedures were conducted for three times each for erect and slouched sitting postures and data were averaged.Results Activities of MT and LT increased significantly more in the slouched sitting posture than in the erect one. There was no significant correlation between kyphotic angle and the area under curve of each muscle.Conclusion Because MT and LT are known as prime movers of scapular rotation, the findings of this study support the notion that slouched sitting posture affects scapular movement. Such scapular dyskinesis during arm elevation leads to scapular stabilizers becoming overactive, and is relevant to muscle fatigue. Thus, slouched sitting posture could be one of the risk factors involved in musculoskeletal pain around scapulae.