Reliability and Validity of a Cervical Muscle Strength Test using a Load-cell-type Strength Measurement Sensor

Jeong-Hoon Lee,Jong-Gil Seo,Byeong-Jin Kim,Jae-Seop Oh 한국임상움직임치료학회 2021 한국임상움직임치료학회지 Vol.1 No.2

Background : Cervical disorder is caused by abnormal cervical movement patterns and cervical muscle imbalance, which are interrelated and result in neck pain and forward head position. In individuals with postural problems, measuring cervical muscle strength allows quantitative assessment of musculoskeletal damage and the effects of neck pain. Various devices have been used to measure cervical muscle strength. However, no studies have assessed cervical muscle strength using a load cell capable of measuring muscle strength in various postures and acquiring biofeedback in real time. Objectives : To evaluate the reliability and validity of a device designed to measure cervical muscle strength in the craniocervical and cervicothoracic regions using a load cell device fixed to a support plate. Methods : The participants were 15 individuals with neck pain. Superficial cervical muscle strength in cervicothoracic flexion (CTF) and cervicothoracic extension (CTE), as well as deep cervical muscle strength in craniocervical flexion (CCF) and craniocervical extension (CCE), were measured using an Hand-held dynamometer (HHD) and fixed-base isometric (load cell) dynamometry. The reliability and validity of the outcome measures using the two devices (HHD and load cell) in four positions were analyzed using intra-class coefficient (ICC) models 3 and 2. Results : Load cell measurements showed excellent intra-rater and inter-rater reliability. HHD measurements exhibited excellent intra-rater and inter-rater reliability. The load cell and HHD measurements showed moderate to excellent validity. Conclusions : The findings revealed excellent validity and reliability of load cell and HHD measurements of muscle strength. Thus, the load cell device can be used as an effective tool for assessing cervical strength. Also, the load cell can express muscle strength in Kilogramme rather than Newton. Therefore, the load cell can be used to measure muscle strength more easily than HHD.

Symmetrical load lifting beside the body compared to in front of the body

Murali Subramaniyam,Seung Nam Min,Heeran Lee,Sangho Park,Se Jin Park 대한인간공학회 2014 대한인간공학회 학술대회논문집 Vol.2014 No.5

This study investigated the lifting loads beside the body compared to in front of the body. Lumbar spinal load during manual lifting is considered an important risk factor for the occurrence of work related back pain. The lumbar spinal load can be expected to increase while manual lifting in front of body compared to beside the body. The horizontal distance of the combined load relative to the low back can be reduced to zero with manual lifting beside the body. Many researchers want to collect quantitative data like low back muscle activities and lumbar loads for preventing back pain. Twenty healthy young men symmetrically lifted hand loads beside the body and in front of the body. The hand loads considered were 0, 6.5, 11.5, and 16.5 kg. Using digital human modeling (DHM) software magnitude of the low-back loads was estimated. The estimated lumbar spinal loads were moment, compression, and joint shear about L4/L5. Subjects’ anthropometric details were used to model digital human in the DHM software. The electromyography was used to measure the symmetry of erector spinae muscle activity (between right and left side) during manual lifting with in front of body and beside body. Specifically, muscle activities obtained with surface electromyography were processed with standard root-mean-square (RMS) amplitude calculations. Finally, the foot balance during manual lifting for the selected postures was measured with foot analyzer. The overall foot balance in the front, back, right, and left side of the body were estimated. Extensor moment was increased with hand loads when lifting in front of the body. Flexor moment was increased with hand loads when lifting beside the body. For the in front of the body lifting technique, the lumbar spinal load values were significantly (p < 0.05) greater than lifting beside the body. There was a significant difference (p < 0.05) in the lumbar spinal loads between the selected postures and for the hand loads. The RMS of erector spinae muscle was significantly (p < 0.05) greater when lifting in front of the body. The comparison of RMS values between the sides of the erector spinae muscle activity reveals that the left side muscle activity was greater than the right side. The foot balance map reveals that significantly (p < 0.05) greater force produced by the left side foot compared with right side to maintain balance when increased hand loads. And also there was a significant (p < 0.05) interaction effect between lifting posture and hand loads in the right side foot balance. The current study showed that lifting a symmetrical load beside the body did reduce lumbar spinal loads and erector spinae muscle activities; this was probably due to the reduced horizontal distance between the hand loads and low back (L4/L5).

예측된 그리고 예측되진 않은 갑작스런 상지로의 부하 적용시 요통 환자와 정상인의 압력 중심 이동 및 근활성 개시에 미치는 영향

채윤원,Chae, Yun-Won 대한물리치료학회 2006 대한물리치료학회지 Vol.18 No.4

Purpose: This study was to compare the effect of center of pressure(COP) displacement and muscle activation onset during expected and unexpected sudden limb loading in subjects with low back pain and healthy control subjects. Most studies of COP displacement and muscle activation onset on postural task focused on sudden trunk loading or gross limb movements. Investigation of the COP displacement and muscle activation onset during expected and unexpected sudden upper limb loading deserves similar attention. Methods: For this study, 14 subjects with low back pain and 12 healthy control subjects are participated. Force plate and surface EMG measures were used to determine COP displacement and muscle activation onset under expected and unexpected sudden upper limb loading. Results: COP displacement and muscle activation onset under unexpected sudden upper limb loading were similar in subjects with low back pain and healthy control subjects. However, COP displacement and muscle activation onset under expected sudden upper limb loading were shortened in healthy control subject but not among the subjects with low back pain. Conclusion: The results provide evidence for impaired feed-forward control in subjects with low back pain.

스미스 머신을 이용한 스쿼트 운동시 중량 부하가 운동역학적 변인과 하지 근육 활성도에 미치는 영향

이성도 ( Seong Do Lee ),이정호 ( Jung Ho Lee ),박은정 ( Eun Jung Park ),이기광 ( Ki Kwang Lee ),손지훈 ( Jee Hoon Sohn ),류재진 ( Jae Jin Ryue ),유연주 ( Yeon Ju Yu ),김용운 ( Yong Woon Kim ),김석범 ( Suk Bum Kim ) 한국스포츠정책과학원(구 한국스포츠개발원) 2011 체육과학연구 Vol.22 No.2

이 연구는 고정된 바벨의 궤적을 제공하는 스미스 머신을 이용한 스쿼트 운동시 다양한 중량 부하가 운동형상학적, 운동역학적, 근육 활성도에 미치는 변화 양상을 조사하고자 하였다. 다양한 중량 부하는 최대중량(1RM)의 100%, 90%, 80%, 70%, 60% 5가지 종류의 부하를 선정하였다. 웨이트 트레이닝 경험이 있는 체육 전공 남자 대학생 10명을 대상으로 스미스 머신에서 스쿼트 동작을 실시하였으며, 중량별 부하는 무선표본하여 적용하였다. 변인을 산출하기 위하여 3차원 동작 분석기, 지면반력기, 근전도를 활용하였으며, 8개의 근육(대퇴직근, 내측광근, 외측광근, 대퇴이두근, 전경골근, 내측비복근, 복직근, 척추기립근)을 선정하였다. 분석 구간은 스쿼드 동작시 신체의 하강, 상승, 전 구간으로 구별하였다. 연구결과 부하의 증가는 발목관절의 최대 각도에 영향을 주지 않은 반면 무릎관절, 고관절의 있어 최대 각도가 작아지는 경향을 보였다. 하지관절의 최대 모멘트는 발목관절, 무릎관절, 고관절에 있어 고관절이 부하의 영향을 가장 많이 받는 것으로 조사되었다. 전후 지면반력은 부하의 영향을 받지 않는 것으로 조사되었다. 근육 활성도에 있어 하강, 상승 구간에 있어 대퇴이두근, 내, 외측광근은 부하의 증가에 따라 근육활동이 증가하는 경향을 나타내었지만, 80%RM- 100%RM 부하 사이에서는 차이가 없는 것으로 나타났다. 상승 구간시 척추기립근에 있어 60%와 100%RM 사이에 있어서 부하간 차이가 있었으나 70%RM 이상의 부하 사이에서는 차이가 없는 것으로 조사되었다. The aim of this study was to investigate kinematic, kinetic and EMG pattern during squat exercise in Smith machine with different loads. We added to subjects different loads (100%RM, 90%RM, 80%RM, 70%RM and 60%RM). Ten healthy male subjects who majored physical education were recruited for this study. Subjects performed consecutive cycles randomly loaded by a barbell. We calculated using three dimensional motion capture system, force plate, surface EMG for caculating variables and we selected eight muscles (rectus femoris, vastus meadialis, vastus lateris, biceps femoris, tibialis anterior, medial gastrocnemius, rectus abdominis and erector spine). We divided squat motion to three phase (Downward, Upward, one cycle). This result were that added loads did not affect to peak ankle joint but affect to peak knee joint and peak hip joint. Peak angle of these joint tended to decrease. The peak ankle angle was not affect by added loading while the added loading were decreased peak angle at the knee and hip joint. Peak moment at hip joint was largely influenced by adding loading among lower extremity joints. There was not significant difference in anterior-posterior GRF. According to add loading, muscle activations of vastus meadialis, vastus lateris and biceps femoris muscle tended to increase while there were not on the basis of 80%RM loading in the upward and downward phases. In the upward phase, erector spine muscle was significant difference between 60%RM and 100%RM loading. However, there was also not on the basis of 70%RM loading.

들기 작업시 중량물의 비대칭 무게중심 및 상체 옆으로 기울임에 따른 허리근육의 Peak EMG 진폭 비교

한승조(Han, Seung-Jo),김선욱(Kim, Sun-Uk) 한국산학기술학회 2012 한국산학기술학회논문지 Vol.13 No.10

본 연구의 목적은 중량물 들기 작업시 비대칭 무게중심과 상체 옆으로 기울임 여부가 어떻게 L5/S1 주변 허 리 근육의 Peak EMG 진폭에 영향을 미치는지를 알아보는 것이다. 요통을 포함한 근골격계질환은 무겁지 않은 물체 의 지속적인 반복 취급뿐만 아니라, 일회성의 커다란 부하도 신체 조직의 부담으로 작용하여 발생할 수 있다. 11명의 20대 대학생 남성은 15.8kg의 물체를 들어올리는 Task를 3회 실행하였다. 이 때 대칭 무게중심의 물체를 상체를 기울 이지 않고 들어 올리는 경우, 비대칭 무게중심의 물체를 상체를 기울이지 않고 들어 올리는 조건, 그리고 비대칭 무 게중심의 물체를 상체를 기울여서 들어 올리는 경우에 따라 6개의 L5/S1 주변의 근육들로부터 Peak EMG 진폭이 수 집되어 분석되었다. 결과는 비대칭 무게중심을 지닌 물체 취급시 무게중심에서 먼 쪽의 허리 근육에서 Peak EMG 진 폭이 발생하고, 그 진폭의 크기는 대칭 무게중심 물체를 취급하는 경우보다 크게 나타났다. 또한, 비대칭 무게중심의 물체를 취급할 경우 물체나 상체를 물체의 무게중심 방향으로 기울이는 것은 기울이지 않을 때보다 대측성 등근육에 서 Peak EMG 진폭 증가시켰다. 이러한 연구 결과는 비대칭 무게중심의 중량물을 들어 올리는 작업에서 요통 발생을 예방하기 위한 행정적인 조치로써 가능하면 상체를 전두면 기준으로 기울이지 않는 작업자 자세 조언이 필요함을 말 해준다. This study was aimed at the relationship between peak EMG amplitude on low back muscles acting on L5/S1 and load center of gravity, trunk lateral bending while lifting an object. Musculoskeletal disorders including low back pain can occur even when handling heavy objects only once as well as when doing non-heavy materials repeatedly. 11 male subjects with average 23 age were required to lift a 15.8kg object symmetrically three times. Peak EMG amplitudes on 6 muscles related with L5/S1 were recorded and analyzed. The lifting conditions consisted of lifting symmetric load with no trunk lateral bending, asymmetric load with no trunk lateral bending, and asymmetric load with trunk lateral bending to the load center of gravity within an object. The results showed that peak EMG amplitude on back muscles contralateral to load center of gravity was observed greater in comparison with the symmetric load. Also, in case of lifting asymmetric load the posture with trunk lateral bending increased peak EMG amplitude on muscles contralateral to load center of gravity more than with no trunk lateral bending. This research can be used as one administrative intervention in order to reduce the low back pain incidence with suggesting workers that they keep the trunk not bending to load center of gravity if possible when lifting a heavy asymmetric object.

보행 시 백팩 부하에 따른 시·공간 변인, 몸통과 어깨 근육의 활동성과 피로도

강서정 대한운동학회 2013 아시아 운동학 학술지 Vol.15 No.1

[INTRODUCTION] The purpose of the study was to investigate how different load weights(0, 10, 20, & 30% BodyWeight(BW)) affect spatiotemporal parameters in gait, trunk and shoulder muscles activity and fatigue. [METHOD] Ten healthy male subjects(Age: 26.9±2.2yrs, Height: 179±5.73cm, Weight: 76.2±5.8kg) were participated in the study. In order to get the spatiotemporal parameters, cameras, markers and Visual 3D program were used. The activity and fatigue in four muscles(Upper Trapezius, Lower Trapezius, Rectus Abdominis, & Erector Spinae) were analyzed with using Wireless EMG System. One-way repeated measures ANOVA and LSD(Post-Hoc) were used to analyze the effects of different load weights on spatiotemporal parameters, trunk and shoulder muscles activity and fatigue. [RESULT] Spatiotemporal parameters(velocity, step length, & stride length) did not show any significant difference. Lower Trapezius muscle showed significant differences on different load weights. The fatigues in Rectus Abdominis and Erector Spinae showed significant differences at over 20%BW load weights. [CONCLUSION] The backpack load in over 20%BW caused more fatigues of trunk muscles than shoulder muscles. Therefore, it might be considered in backpack design. [서론] 본 연구의 목적은 보행 수행 시 백팩 부하 변화(0, 10, 20, & 30% BodyWeight(BW))에 따른 몸통과 어깨 근육의 활동성과 피로도, 시․공간 보행 변인의 변화를 분석하고자 하였다. [방법] 건강한 성인 남성 10명(연령: 26.9±2.2세, 키: 179±5.73cm, 체중: 76.2±5.8kg)이 연구에 참여하였다. 시․공간 보행 변인을 얻기 위해 카메라, 마커, Visual 3D 프로그램이 사용되었고, 위등세모근, 아래등세모근, 배곧은근, 척주세움근의 활동성과 피로도 분석을 위해 무선근전도 시스템이 사용되었다. 백팩 부하 변화에 따른 변인의 변화를 분석하기 위해 one-way repeated measures ANOVA가 사용되었고, 사후분석 검정으로 LSD 를 사용하였다. [결과] 백팩 부하 변화에 따라 시․공간 보행 변인은 통계적으로 유의한 변화를 나타내지 않았고, 아래등세모근의 활동성이 백팩 부하 변화에 따라 유의하게 변화하였다. 배곧은근과 척주세움근의 피로도가 백팩 부하 20%BW에서부터 유의하게 변화하였다. [결론] 20%BW 이상의 백팩 부하는 어깨 근육 보다는 몸통 근육인 배곧은근과 척주세움근에 피로를 유발시키는 것으로 나타나 백팩 디자인 시 고려되어야할 사항으로 생각되며, 오랜 시간 20%BW 이상의 부하로 보행을 하는 여행자나 군인들에게 배곧은근과 척주세움근의 강화가 필요할 것으로 사료된다.

예상 부하와 갑작스런 부하에 따른 정상 성인의 복직근과 요부 척추기립근의 근활성도 차이

국중석,김재헌,이준형,박부애,박다솜,유혜인,Kuk, Jung-Seok,Kim, Jae-Hun,Lee, Jun-Hyeong,Park, Boo-Ae,Park, Da-Soom,Yu, Hye-In 대한물리치료과학회 2011 대한물리치료과학회지 Vol.18 No.4

The purpose of this study was to investigate the responses of the trunk muscle during expected and unexpected sudden loadings of the hands on the sagittal plane. Twenty, young healthy adults(male 10, female 10) were participated to two different loading conditions : expected and unexpected sudden loadings. Different weights were dropped in hand : 5lb, 6lb, 7lb for male, and 3lb, 4lb, 5lb for female. EMG activity of rectus abdominalis and erector spine muscle were collected. Rectus abdominalis and lumbar erector spine muscle activity significantly increased in unexpected sudden loadings than expected sudden loadings(p<.05). This results indicate that co-contraction of abdominal and back muscle contribute for dynamic spinal stability during expected or unexpected activities of daily living. Preparatory adjustments can be made which reduce the postural perturbation to sudden load and prevent low back injuries.

엎드려 무릎관절 굽힘 자세에서 엉덩관절 폄 동작 시 무게 부하 변화에 따른 큰볼기근과 넙다리두갈래근의 두께 비교

장은미,정다은,Eun-Mi Jang,Da-Eun Jung 대한고유수용성신경근촉진법학회 2023 PNF and Movement Vol.21 No.3

Purpose: This study set out to investigate the effects of prone hip extension with knee flexion (PHEKF) exercises according to external load on the thickness of the gluteus maximus (Gmax) and biceps femoris (BF). Methods: Twenty-three healthy men participated in this study. All subjects randomly practiced PHEKF under the burden of external loads created by sandbags (0 kg, 1 kg, and 2 kg). Rehabilitative ultrasound imaging (RUSI) was used to measure the thickness of the Gmax and BF during the PHEKF with different external loads. Results: The thickness of the Gmax was highest during the 2 kg resistance exercise and lowest at 0 kg. The thickness of the Gmax was significantly increased at 1 kg and 2 kg compared to 0 kg and significantly increased at from 1 kg to 2 kg (p < 0.05). The thickness of the biceps femoris was highest at 0 kg and lowest at 2 kg. The thickness of the biceps femoris muscle was significantly reduced at 1 kg and 2 kg compared to 0 kg (p < 0.05), but there was no significant difference between 1 kg and 2 kg (p > 0.05). Conclusion: The thickness of the Gmax was increased by applying PHEKF with a higher external load, whereas the muscle thickness of the biceps femoris decreased. These results suggest that the application of external loads during PHEKF exercises may be an effective method for selective strengthening of the Gmax.

The Effect of Unstable Support Surface Changes on Upper and Lower Limbs on Core Stabilizing Muscle Activation during Plank Exercise

조성학 대한물리치료학회 2024 대한물리치료학회지 Vol.36 No.3

Purpose: This study aims to suggest effective exercise methods for individual situations by examining changes in trunk muscle activity when plank exercise is performed using unstable support surfaces for the upper and lower limbs, respectively. Methods: Thirty-six adult males were divided into 3 groups. The subjects were divided into three groups of 12 people through a lottery. The first group was the standard plank group (Plank), the second group was the Upper Unstable Plank group (UUP), which provided insta- bility to the upper extremities, and the third group was the Lower Unstable Plank group (LUP), which provided instability to the lower ex- tremities. To compare the activity of trunk muscles during each plank movement, EMG was used to compare the muscle activity of the external oblique (EO), rectus abdominis (RA), and erector spinae (ES) muscles. Muscle thickness of the transverse abdominis (TrA) was measured using ultrasound. Results: This study showed that mean muscle activity of EO and RA was significantly increased in the UUP and LUP groups compared to the Plank group (p < 0.05). ES was not significantly different among the three groups. The mean muscle thickness of TrA was significantly increased in LUP (p < 0.05). Conclusion: According to the results of this study, when providing instability in the plank posture to enhance trunk stability, it is recom- mended to provide instability to the lower extremities rather than the upper extremities.

Effects of Unstable Support Surface and Weight Load on Muscle Activity and Balance During Squat Exercise

Hyeonsu Kim,Keoncheol Lee 대한스포츠물리치료학회 2020 정형스포츠물리치료학회지 Vol.16 No.1

Purpose: The purpose of this study is to find and compare the differences between muscle activity change and balance during unstable support and weight load during the squat exercise. Methods: The subjects were 36 normal adults (18 male and 18 female). It was randomly divided into a stable support group (control group), an unstable support group (experimental group 1), and an unstable support surface weighted group (experimental group 2), and the squat exercise was performed for 4 weeks. Togu jumper (TOGU, Germany) was applied as the unstable support surface, and 4 kg of Kettlebell (Schmidt, China) was applied for the weight load. The squat exercise was conducted three times a week and consisted of 10 minutes of warm-up, 20 minutes of the main exercise, and 10 minutes of down exercise. This exercise was repeated three sets of 15 squats. Results: The result is as follows. First, changes in muscle activity according to the experimental period increased in both the stable and unstable support groups and the unstable support and the largest increase in the weight load group (p<.05). Second, change in the balance ability according to the experiment period was most improved in the unstable support according to the experiment period in the change of Endpoint excursion (EPE) and the Directional control (DCL) than the other two groups (p<.05). Conclusion: Squat exercise is effective as an exercise to improve the strength and balance of leg muscles. As in previous studies, it was found that exercise is more effective on the unstable support than on the stable support and that it is most effective to give weight load on the unstable support.