Background: A decrease in physical activity has been observed due to the global pandemic, resulting in the onset and progression of musculoskeletal disorders as chronic diseases. Objectives: This study aimed to assess the difference in the degree of contraction of the lower limb muscles between the existing vertical vibration method and a new cross-vibration method. Design: Randomized controlled trial. Methods: The exercise program using whole-body vibration equipment was conducted for 12 sessions, 25 min per session, three times per week for 4 weeks. Results: The changes over time showed a significant difference in cross-alternating vibrations (P<.05), except for the lateral gastrocnemius and tibialis anterior, with no significant difference in sonic vertical vibration (P>.05). The interaction between time and group was significant for all muscles (P<.05), except for the biceps femoris, with differences between before the program and at 2 and 4 weeks after the program revealed in the post-hoc analysis. Conclusion: Future studies should further evaluate the use of CAV exercise devices as auxiliary equipment in exercise by assessing different groups and variations in intensity.

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.

Purpose: 본 연구의 목적은 4주기간동안 횡격막 호흡을 적용한 기구 필라테스 운동이 20대 성인의 유연성, 복부 근 두께, 근육량, 체지방, 호흡에 미치는 영향에 대해 알아보고자 하는 것이다. Methods: 근골격계 질환이 없는 대상자 35명을 대상으로 수행하였으며, 횡격막 호흡을 하는 그룹과 횡격막 호흡을 하지 않는 그룹으로 나누었으며, 두 그룹 모두 필라테스를 수행하였다. 실험에 사용한 기기로는 Ultrasonography(US), Pulmonary function tests(FEV1 / FVC), Bioeletic Impedance Analysis, Sit and reach test를 사용하였다. 정규성 검증을 실시한 후, 반복측정분산분석 (repeated measures of ANOVA)를 사용하여 운동 전, 호흡을 적용한 운동, 호흡 비적용 운동을 비교하였다. 사후 분석을 위해 Fisher’s LSD를 실시하였다. Results: 필라테스 운동은 복근의 두께와 유연성에 긍정적인 영향을 미쳤습니다. SaR test는 운동 전과 호흡을 적용한 운동과 호흡을 적용하지 않은 운동 사이에 유의한 유의성을 보였다(P <0.05). 근육두께 측정 TRA, EO, IO 모두 운동 전보다 호흡 적용 운동과 비호흡 운동에서 유의한 차이가 있었고(P <0.05), TRA와 IO에서는 추가 시간 사이에 유의한 차이가 없었다. 호흡하지 않는 운동(P >0.05). 그러나 EO에서는 호흡운동을 추가한 시간과 호흡운동을 하지 않은 시간 사이에 유의한 차이가 있었다( P <0.05). Conlusion: 결론적으로, 횡격막 호흡을 이용한 필라테스 운동과 횡격막 호흡이 없는 필라테스 운동은 복근의 두께와 유연성에 긍정적인 영향을 미치는 것으로 나타났다. 그러나 횡격막 호흡과 비횡격막 호흡 사이에는 큰 차이가 없었다.

본 연구의 목적은 필라테스 브릿지 동작 시 소도구의 적용과 발의 불안정성 차이에 따른 신체 근육의 근전도를 비교·분석하는데 있었다. 본 연구의 대상자는 20대 남성 18명을 대상으로 실시하였고(연령, 22.3±2.1세; 신장, 173.89±4.51cm; 체중, 72.61±4.13kg; 신체질량지수, 24.03±1.31kg/m2), 필라테스 브릿지는 소도구 적용(도구 없음, 링, 짐볼)과 발의 불안정성(기본 바닥, 폼롤러, 보수볼) 차이에 따른 9 가지 동작을 수행하였으며, 표면전극 부착 부위는 신체 우측의 상복직근, 하복직근, 외복사근, 장내전근, 대 퇴직근, 외측광근, 전경골근, 및 대퇴이두근으로 설정하였다. 본 연구의 결과는 다음과 같다. 필라테스 브릿지 동작 시 짐볼의 적용이 신체 근육의 근활성도에 효과적인 소도구로 검증되었고, 보수볼의 적용이 신체 근육의 근활성도에 가장 높은 발의 불안정성으로 검증되었다. 이상의 결과를 종합해보면, 필라테스 브릿지 동작 시 짐볼과 보수볼의 적용이 신체 근육의 근활성도에 지대한 영향력을 미친 것으로 나타났다. 따라서 본 연구의 결과는 신체 근력 강화를 위한 효율적인 필라테스 브릿지 운동을 제시할 수 있을 것으로 기대된다.

Background: Patients with low back pain (LBP) experience misalignments in the center of pressure (COP) and muscle imbalances due to frequent onesided posture adjustments to avoid pain. Objectives: To identify the effects of Squat Exercises with Vertical Whole-Body Vibration on the Center of Pressure and Trunk Muscle Activity. Design: Randomized controlled trial. Methods: Thirty LBP patients with an imbalance in the COP were sampled and randomly assigned to an experimental group of 15 patients who under went an intervention involving squat exercises with vertical WBV and a control group of 15 patients who were treated via a walking intervention. As pretests before the interventions, the subjects’ COP was identified by measuring their stability index (ST), and erector spinae, rectus abdominis, transverse abdominis, gluteus medius muscle activity was analyzed by determining the % reference voluntary contraction (%RVC) value using surface electromyography while sit to stand. After four weeks, a post test was conducted to remeasure the same variables using the same methods. Results: Statistically significant differences were found in the ST (P<.01) and trunk muscle (P<.05, P<.001) in the experimental group before and after the intervention. In terms of the differences between the left- and right-side (RL) muscle activity, only the transverse abdominis (TrA) and gluteus medius (GM) exhibited statistically significant increase (P<.05). A comparison of the groups showed statistically significant differences in the TrA with respect to muscle activity (P<.05) and in the RLTrA and RLGM in terms ofthe difference between left- and right-side muscle activity (P<.01). Conclusion: Squat exercises with vertical WBV produced effective changes in the COP of patients with LBP by reducing muscle imbalances through the delivery of a uniform force. In particular, strengthening the TrA and reducing an imbalance in the GM were determined to be important factors in improving the COP.

Background: Backpacks are one of the most widely used accessories in modern society. However, previous studies have shown that carrying a backpack can cause various musculoskeletal problems. Objectives: To investigate the effects of a body-adhesive backpack on craniovertebral angle, sagittal shoulder angle and the muscle fatigue in the upper extremity. Design: Randomized cross-over design. Methods: For this study, 36 healthy university students participated in this study. The experiment was conducted three times using common backpack, and body-adhesive backpack condition. The angles of the cervical spine and shoulder joints of the subjects were calculated without the backpack. Electrodes were placed at upper trapezius, lower trapezius, rectus abdominis and erector spinae to check for muscle fatigue. Subjects carried a backpack and walked on a treadmill for 15 minutes at 4 km/h. The muscle fatigue signal was also measured while walking. After walking, the craniovertebral and sagittal shoulder angles were measured again while subjects carried backpack. Results: As a result of this study, body-adhesive backpack condition showed significant decrease and significant increase in craniovertebral angle and sagittal shoulder angle than common backpack (P<.05). Body-adhesive backpack condition showed significant decrease in upper trapezius, lower trapezius, erector spinae, and rectus abdominis when compared to a common backpack (P<.05). Conclusion: This study suggests that a body-adhesive backpack is more beneficial in correcting body posture than a common backpack.

본 연구의 목적은 정적 스쿼트 동작 시 발란스 보드와 전신 진동자극기 적용이 신체 근육의 근활성도 변화에 어떠한 영향을 미치는지 검증하는 것이었다. 본 연구의 대상자는 20대 남성 20명을 대상으로 실시하였고(연령, 21.90±0.36 세; 신장, 174.30±1.09 cm; 체중, 66.50±1.00 kg; 신체질량지수, 21.90±0.31 kg/m2), 3가지의 기본 정적 스쿼트 동작, 발란스 보드를 적용한 정적 스쿼트 동작 및 전신 진동자극기를 적용한 정적 스쿼트 동작을 수행하였으며, 표면전극을 부착한 부위는 신체 근육의 우측 복직근, 내복사근, 외복사근, 대퇴직근, 외측광근 및 내측광근으로 설정하였다. 실험을 통해 획득된 본 연구의 결과 는 다음과 같다. 복직근, 내복사근 및 외복사근의 근활성도는 발란스 보드와 전신 진동자극기를 적용한 정적 스쿼트 동작 시 통계적으로 높게 나타났고(p=.001, p=.004, p=.000), 대퇴직근, 외측광근 및 내측광근의 근활성도는 전신 진동자극기를 적용한 정적 스쿼트 동작에서 통계적으로 가장 높게 나타났다(p=.000). 본 연구의 결과는 향후 정적 스쿼트 훈련 적용 시 효과적인 신체 근육을 강화시키기 위한 프로그램의 기초 자료가 될 것으로 기대된다.

Background: Whole body-electromyostimulation (WB-EMS) is widely used for the rehabilitation and recovery of patients with various neuromusculoskeletal disorders. Objects: To objectively measure changes in lower extremity and abdominal muscles after sit-to-stand dynamic movement training using WB-EMS. Methods: A total of 46 healthy adults (23 experimental and 23 control subjects) performed sit-to-stand exercise; the experimental group with WB-EMS, and the control group without WB-EMS. The muscle activity of the lower extremity, and the muscle thickness of the lower extremity and abdominal muscles were measured before and after the intervention. Results: In terms of electromyographic activity, there was a significant interaction effect for the rectus femoris (RF) muscle (F=30.212, p=.000). With regards to ultrasonographic imaging, the muscle thickness of the RF muscle had a significant interaction effect at the muscle contraction ratio (F=8.071, p=.007). The deep abdominal muscles, such as the transverse abdominal (TrA) and internal oblique (IO) muscles, also showed significant interaction effects at the muscle contraction ratio (F=5.474, p=.024, F=24.151, p=.000, respectively) Conclusion: These findings suggest that WB-EMS may help to improve the muscular activity of the RF muscle, and the muscle thickness of the RF muscle and deep muscles such as the TrA and IO muscles.

본 연구의 목적은 플랭크 운동 시 세라밴드 적용 유·무에 따른 신체 근육의 근활성도를 비교·분석하는데 있었다. 본 연구의 대상자는 건강한 20대 남성 12명을 대상으로 실시하였고(연령, 21.75±0.57 세; 신장, 173.33±1.34cm; 체중, 65.92±1.64kg; 신체질량지수, 21.93±0.46kg/m2), 풀 플랭크, 엘보우 플랭크, 사이드 플랭크, 및 리버스 플랭크 운동은 4가지의 세라밴드(사용 안함(WT), 빨간색(RT), 파란색 (BT), 은색(ST))를 적용하여 수행하였으며, 표면전극 부착 부위는 척추기립근(ES), 삼각근(DA), 외복사근 (EO), 복직근(RA), 대퇴직근(RF), 광배근(LD), 대흉근(PM), 및 대퇴이두근(BF)으로 설정하였다. 본 연구의 결과는 다음과 같다. 풀 플랭크 동작 시 ES, DA의 근활성도는 WT적용 시 가장 높게 나타났고(p<.05), EO, RA, RF, PM의 근활성도는 ST적용 시 가장 높게 나타났다(p<.05). 엘보우 플랭크 동작 시 ES, DA의 근활성도는 WT적용 시 가장 높게 나타났고(p<.05), RF, PM의 근활성도는 ST적용 시 가장 높게 나타났다 (p<.05). 사이드 플랭크 동작 시 ES, EO, RA, RF, LD, PM, BF,의 근활성도는 ST적용 시 가장 높게 나타 났다(p<.05). 그리고 리버스 플랭크 동작 시 DA, EO, RA, RF, LD, PM, BF,의 근활성도는 ST적용 시 가장 높게 나타났다(p<.05). 따라서 본 연구의 결과는 향후 플랭크 운동 적용 시 효과적인 신체근육을 강화시 키기 위한 훈련프로그램의 자료가 될 것으로 기대된다.

Whole body fatigue detection is an important phenomenon and the factors contributing to whole body fatigue can be controlled if a mathematical model is available for its assessment. This research study aims at developing a model that categorizes whole body exertion into fatigued and non-fatigued states based on physiological and perceived variables. For this purpose, logistic regression was used to categorize the fatigued and non-fatigued subject as dichotomous variable. Normalized mean power frequency of eight muscles from 25 subjects was taken as physiological variable along with the heart rate while Borg scale ratings were taken as perceived variables. The logit function was used to develop the logistic regression model. The coefficients of all the variables were found and significance level was checked. The detection accuracy of the model for fatigued and non-fatigues subjects was 83% and 95% respectively. It was observed that the mean power frequency of anterior deltoid and the Borg scale ratings of upper and lower extremities were significant in predicting the whole body fatigued when evaluated dichotomously (p < 0.05). The findings can help in better understanding of the importance of combined physiological and perceived exertion in designing the rest breaks for workers involved in squat lifting tasks in industrial as well as health sectors.

Background:Individuals with spinal cord injury (SCI) rely on their upper limbs for body-lifting activity (BLA). While studies have examined the electromyography (EMG) and kinematics of the shoulder joints during BLA, no studies have considered foot position during BLA.Objects:This study compared the effects of different foot positions during BLA on the shoulder muscle activities, peak plantar pressure, knee flexion angle, and rating perceived exertion in individuals with SCI.Methods:The study enrolled 13 mens with motor-complete paraplegic SCI, ASIA (American Spinal Injury Association) A or B. All subjects performed BLA with the feet positioned on the wheelchair footrest and on the floor independently. Surface EMG was used to collect data from the latissimus dorsi, pectoralis major, serratus anterior, and triceps brachii. The peak plantar pressure was measured using pedar-X and the knee flexion angle with Image J. Borg’s rating perceived exertion scale was used to measure the physical activity intensity level. The paired t-test was used to compare the shoulder muscle activities, peak plantar pressure, knee flexion angle, and rating perceived exertion between the two feet positions during BLA.Results:The activity of the latissimus dorsi, pectoralis major, serratus anterior, and triceps brachii and rating perceived exertion decreased significantly and the peak plantar pressure and knee flexion angle increased significantly when performing BLA with the feet positioned on the wheelchair footrest compared with on the floor (p<.05).Conclusion:These findings suggest that individuals with SCI may perform BLA with the feet positioned on the wheelchair footrest for weight-relief lifting to decrease the shoulder muscle activities and the rating perceived exertion and to increase the peak plantar pressure and the knee flexion angle.

본 연구에서는 고강도 운동 후 전신진동이 근피로도 감소와 심박회복율에 미치는 효과를 알아보고자 하였다. 피험자 는 총 20명으로 진동을 제공받는 그룹과 진동을 제공받지 않는 그룹으로 구성되어 있다. 고강도 운동은 경사 8.5도와 보행속도 4km/h를 30분간 제공하였고, 그룹별 진동유무별 의자형 진동기 위에서 30분간 휴식을 취하였다. 전신진동자 극은 10Hz의 진동주파수와 5mm의 진폭을 제공하였다. 진동유무별 피로도 감소와 심박안정화 효과를 검증하기 위해 혈중 젖산농도와 실시간 심박수 변화를 측정하였다. 실험결과, 진동을 제공받는 그룹에서 95.2% 수준의 더 큰 근피로도 감소결과와 50.67%의 더 빠른 심박회복율 결과를 보였다. 이는 고강도 운동 후 전신진동이 근육속 혈관을 지속적으로 자극하여 운동 후 초과산소섭취를 빠르게 해소하고 혈액순환 기능을 증진시켜 피로도를 감소시킨다. 고강도 운동 후 전신진동을 이용한 휴식은 노약자나 여성들에게 운동 후 다른 육체적 활동 없이 마무리운동으로 긍정적 효과를 기대할 수 있다.

While working in an industrial environment which requires extended periods of upright posture; workers tend to develop muscle fatigue due to the constant load on lower-limb muscles. In addition, when working while bending knees; muscle fatigue of lower back and hamstrings is increased due to the abnormal posture. This can lead to damage of muscles, induce musculoskeletal disorders, and reduce long-term working efficiency. Recent medical studies have shown that long-term working in an upright posture can induce musculoskeletal disorders such as foot fatigue, edema, pain and varicose veins. Likewise, medical and rehabilitation expenses have grown due to the increase in musculoskeletal conditions suffered by workers. For this problem, we aim to develop a device that can reduce the physical fatigue on the lower limbs by supporting the weight of workers during the extended periods of upright and bending postures in the industrial environments. In this paper, we have designed and manufactured a wearable weight support system; with a user intention algorithm that the users can maintain various postures. For validation of the developed system, we measured the muscle activity of the users wearing the system with EMG sensors.