Bio-Medical Materials and Engineering 24 (2014) 245–254 DOI 10.3233/BME-130805 IOS Press
245
Activity Analysis of Trunk and Leg Muscles During Whole Body Tilt Exercise Chang Ho Yu a, Sun Hye Shinb, Ho Choon Jeong c, Deung Young God and Tae Kyu Kwon a,e* a
Division of Biomedical Engineering, Chonbuk National University, Deokjin-Dong 1-Ga, Jeonju, Jeonbuk 561-756, South Korea b Department of Healthcare Engineering, Chonbuk National University, Deokjin-Dong 1-Ga, Jeonju, Jeonbuk 561-756, South Korea c CyberMedic Co, Iksan, Jeonbuk, South Korea d Department of Junior Secondary School Special Education, Kangnam University, 40 Gangnam-ro, Giheung-gu, Yongin, Gyeonggi 446-702, South Korea e Bioengineering Research Center for the Aged, Chonbuk National University, Jeonju, Jeonbuk 561756, South Korea
Abstract. The objectives were to assess the trunk and leg muscle activities during the trunk tilt exercise by a 3D dynamic exercise device capable of active and passive movements, to study the evaluation of Root Mean Squire (RMS), and to investigation the influence of the trunk positions on these muscle activities. Eighteen healthy volunteers were selected. None of the subjects had any history of lumber and trunk muscle problems. Rotation capability was enabled for the investigation of A (anterior), R (right), P (posterior), L (left), AR (anterior right), AL (anterior left), PR (posterior right), PL (posterior left) tilt directions. EMG signals of trunk (rectus abdominis, external obliques, latissimus dorsi, erector spinae) muscles and leg (rectus femoris, Biceps femoris, Tibialis Anterior, gastrocnemius) muscles were taken out. Root Mean Squire (RMS) values were calculated. The results of this study indicate that different exercise patterns can be applied depending on the exercise types, which are appropriate and necessary to each user. We believe that the human body can be maintained in equilibrium through the interaction between the position and movement execution of the human body, contributing to the improvement of body balance control. Further quantitative data collection and analysis related to the development of various spinal stabilization exercise programs is required. In the near future, we will conduct a study concerning the effects of trunk tilt exercise in active and passive modes on the strength of the tilting muscles and postural balancing ability. Keywords: Trunk stabilization exercise, whole body tilt, active Tilt, passive tilt, EMG
1. Introduction Eighty percent of people in a modern society, who spend most of their time sitting, are experienced back pain; 15% of these people suffered chronic low back pain. Moreover, low back pain creates many problems in regard to the patients’ physical function and moving capacity which limits the patients’ working ability to a great extent, leading to great social economic loss[1-2]. In other words, low back pain is a common disease among humans, and it is one of the main causes of labor losses [3-5]. Spine *Corresponding author. E-mail: [email protected] 0959-2989/14/$27.50 © 2014 – IOS Press and the authors. All rights reserved
246
C.H. Yu et al. / Activity analysis of trunk and leg muscles during whole body tilt exercise
stabilization is defined as a person’s ability to make large or subtle movements of the spinal joints, both consciously and unconsciously [6, 7]. Currently, it is known to be an essential approach for the treatment of patients with low back pain [8- 9]. Spinal stability is believed to play an important role in the prevention and rehabilitation of lumbar spine injury. Therefore, exercises for improving spinal stability are performed widely in sports and rehabilitation. Spinal stabilization exercises include the pelvic tilt exercise, which can activate areas around the spine; naval contraction, where selective abdominal muscle contraction is possible without any movement in the spine; and other exercises using mats, treatment with tables, balls, dumbbells, balance plates, etc. [10-13]. In recent years, isometric exercises have been used to achieve spinal stabilization through the trunk tilt movement in a standing position by using three-dimensional (3D) motion. These exercises contribute to both low back pain reduction and postural balance through strengthening of the trunk muscles. Many studies about these exercises are currently being conducted. Koh et al. [14] analyzed the results regarding the balancing ability of older women and the changes in the thickness of the transversus abdominis muscle and multifidus muscle brought about by an 8week lumbar stabilization exercise program by using a 3D Pegasus system. It is reported that the exercise contributed to positive effects on isometric strength as well as the enhancement of balancing ability. Kim et al. (2011) [15] conducted an experiment for chronic low back pain patients in their 20s by dividing them into 2 groups: a lumbar stabilization exercise group using typical exercise balls, and a group using a 3D air balance system (SNS Korea Co., Korea). After the 2 groups completed the lumbar stabilization training, the visual pain scale scores, limitation on daily life, weight shift angles in 8 directions, and postural disturbance during weight shift were assessed. Then, the effects of these 4 variables on the patients’ postural sway and weight distribution were analyzed. According to the results, in terms of the patients’ muscle balance during active weight shift in the left, right, and diagonal directions, lumbar stabilization exercise using the 3D air balance system was more effective for coordinated movements than that performed using exercise balls. Moreover, 3D exercise was effective for the reduction of posture sway during active weight shift. The 3D isometric exercise equipment examined in existing studies is divided into two movements: a self-generated active movement in the angle and direction steered by the user, and a passive movement generated by the driving of the equipment. However, the exercise equipment used in the current study enables the conversion between active and passive movements. Active and passive movements stimulate different locations of muscle mass and physical characteristics; however, only the effects of 3D exercise equipment on muscle strength were discussed in the research to date regardless the different modes of exercise. Therefore, in this study, we aimed to compare and analyze the differences in trunk muscle strength caused by the body tilt movements with active and passive exercise modes. 2. Experimental methods 2.1. Subjects In this study, eighteen healthy volunteers (18 males, height 176±2.3 cm; mass 69.9±2.7 kg; age 24.7±0.5 years) were investigated. Conforming to the Declaration of Helsinki (1964), written informed consent was obtained from all subjects. None of the subjects had any history of lumber and trunk muscle problems. The investigation was performed in a device for trunk muscle diagnosis and treatment (SpaceBlance 3D, CyberMedic Co. & Chonbuk National Univ., Korea ; Fig.1(a)).
C.H. Yu et al. / Activity analysis of trunk and leg muscles during whole body tilt exercise
247
Fig. 1.(a) 3D dynamic exercise device (SpaceBalance 3D, CyberMedic Co. &Chonbuk National Univ., Korea), (b) Explanation of 8 tilting directions during the trunk tilt exercise modes of the SpaceBalance 3D. (c) Passive tilt mode of the SpaceBalance 3D. (d) Active tilt mode of the SpaceBalance 3D
2.2. System configuration As shown in Fig. 1.(b), the trunk and leg muscles generated by tilting in 8 different directions such as A (anterior), R (right), P (posterior), L (left), AR (anterior right), AL (anterior left), PR (posterior right), PL (posterior left) were measured during the trunk tilt exercise modes of a 3D dynamic exercise device. This device applies forces on the trunk by tilting the whole body from a neutral upright position. Subjects are fixed at their feet and hips, but the trunk remains unsupported. During the different tilt positions, the subject has to simply stabilize his or her upper body in the body axis. For this investigation, subjects held their arms crossed against their chests. Exact body and arm positioning throughout the whole investigation was controlled by the examiner. This 3D dynamic equipment was capable of moving 100 degrees in the A-P direction, 180 degrees in the L-R direction, 100 degrees in the AR- PL direction and 100 degrees in the AL-PR direction since it can be rotated in 3D space. For the recording of the EMG signals, an 8-channel surface EMG system was used (Bignoli system, Delsys. Inc., USA). All raw EMG signals were band pass-filtered between 6 to 400 Hz and amplified. The sampling rate was 1000 Hz and the signals were converted from an analogue voltage to a digital signal at 1000Hz (A/D conversion) before being transformed into a personal computer. The electrode was attached after removing the keratinous skin layer with sterilization alcohol to reduce the skin resistance against the surface EMG signals. We measured trunk (rectus abdominis, external obliques, latissimus dorsi, erector spinae) muscles and leg (rectus femoris, Biceps femoris, Tibialis Anterior, gastrocnemius) muscles during these exercise. Root mean squire (RMS) values were used for the analysis method. RMS values were calculated to quantify the amplitude of the EMG signals. 2.3. Experimental equipment and procedures This device (Space Blance 3D, CyberMedic Co. &Chonbuk National Univ., Korea) has active and passive tilt modes according to the driven approach in Fig. 1(c), and (d). This device is divided into two exercise modes: a self-generated active movement in the angle and direction steered by the user (active tilt mode), and a passive movement generated by the driving of the equipment (passive tilt
248
C.H. Yu et al. / Activity analysis of trunk and leg muscles during whole body tilt exercise
mode). Our experimental procedures were conducted by explaining the analysis of trunk and leg muscle activities generated by 30 degrees in 8 tilting directions with both the active and passive tilt modes. The applied tilting directions are A (anterior), R (right), P (posterior), L (left), AR (anterior right), AL (anterior left), PR (posterior right), and PL (posterior left).The subject then maintained their COG (center of gravity) to the appointed 8 tilting directions twice for 10 sec, respectively. 20 seconds of relaxation was allotted during targeting change. To recover the muscular strength, 20 minutes of relaxation was allotted between the active tile and passive tile modes. As shown in Fig. 2, the electrode was attached after removing the keratinous skin layer with sterilization alcohol to reduce the skin resistance against the surface EMG signals. The trunk (rectus abdominis, external obliques, latissimus dorsi, erector spinae) muscles and leg (rectus femoris, Biceps femoris, Tibialis Anterior, gastrocnemius) muscles were measured during these exercise.
Fig. 2.Muscle measured in upper and lower limbs for verifying muscular activities
2.4. Data analysis Data analysis was completed using the statistical software program SPSS PASW statistics 18(SPSS Inc., Chicago, IL, USA) for Windows Ver. 12.0. The Kolmogorov-Smirnov test (K–S test) was used to evaluate the differences in EMG activity between the active mode and passive mode for changes in the measured parameters. A P value of less than 0.05 was considered statistically significant. 3. Results 3.1. Analysis of trunk muscle activities Figures 3–6 illustrate trunk muscle activities according to the active and passive movements generated by tilting in 8 directions. The y-axes represent Root Mean Square (RMS) values converted from the electromyography (EMG) data, and the x-axes indicate the 8 directions. Figure 3 represents the RMS values of the left and right sides of the rectus abdominis. In the case of the left rectus abdominis, muscle activity maintaining the active tilt mode in the P and PL directions was higher than that in the passive tilt mode. In the case of the right rectus abdominis, muscle activity in the active tilt mode in the P and PR directions was significantly higher. Rectus abdominis muscle activities during the active and passive tilt modes demonstrated significantly higher RMS values in the
C.H. Yu et al. / Activity analysis of trunk and leg muscles during whole body tilt exercise
249
P direction than those in the A direction, regardless whether the muscle was in the active or passive mode. Figure 4 illustrates the RMS values of the left and right external oblique. In the case of the left external oblique, maintaining the passive tilt mode in the AR and AL directions resulted in significantly higher values, whereas in the case of the right external oblique, maintaining the passive tilt mode in the PL direction resulted in higher values (p < 0.05). In terms of external oblique muscle activity in both the active and passive tilt modes by direction, tilting in the PR and R directions caused much higher values of muscle activity than tilting in the PL and L directions in the case of the left muscle. In contrast, in the case of the right muscle, the opposite tendency was observed: tilting in the PL and L directions caused much higher values than tilting in the PR and R directions.
Fig. 3.Rectus abdominis of RMS in passive and active tilt training in eight directions
Fig. 4.External oblique of RMS in passive and active tilt training in eight directions
According to the RMS values of the left and right latissimus dorsi shown in Figure 5, muscle activities in the passive tilt mode showed higher values in all directions except for the A and PL directions in the case of the left latissimus dorsi. Muscle activities in the passive tilt mode were higher in the P, L, and AL directions in the case of the right latissimus dorsi. However, there were no significant differences in the muscle activities in different directions.
250
C.H. Yu et al. / Activity analysis of trunk and leg muscles during whole body tilt exercise
Fig. 5.Latissimus dorsi of RMS in passive and active tilt training in eight directions
Fig. 6.Erector spinae of RMS in passive and active tilt training in eight directions
3.2. Analysis of leg muscle activities As shown in Fig. 7, there was no significant tilting mode-related difference in the muscle activities of the left rectus femoris. In the case of the right rectus femoris, the muscle activities generated by maintaining the passive tilting mode in the PR and PL directions were significantly lower than those generated by maintaining the active tilting mode in the same directions (p
245
Activity Analysis of Trunk and Leg Muscles During Whole Body Tilt Exercise Chang Ho Yu a, Sun Hye Shinb, Ho Choon Jeong c, Deung Young God and Tae Kyu Kwon a,e* a
Division of Biomedical Engineering, Chonbuk National University, Deokjin-Dong 1-Ga, Jeonju, Jeonbuk 561-756, South Korea b Department of Healthcare Engineering, Chonbuk National University, Deokjin-Dong 1-Ga, Jeonju, Jeonbuk 561-756, South Korea c CyberMedic Co, Iksan, Jeonbuk, South Korea d Department of Junior Secondary School Special Education, Kangnam University, 40 Gangnam-ro, Giheung-gu, Yongin, Gyeonggi 446-702, South Korea e Bioengineering Research Center for the Aged, Chonbuk National University, Jeonju, Jeonbuk 561756, South Korea
Abstract. The objectives were to assess the trunk and leg muscle activities during the trunk tilt exercise by a 3D dynamic exercise device capable of active and passive movements, to study the evaluation of Root Mean Squire (RMS), and to investigation the influence of the trunk positions on these muscle activities. Eighteen healthy volunteers were selected. None of the subjects had any history of lumber and trunk muscle problems. Rotation capability was enabled for the investigation of A (anterior), R (right), P (posterior), L (left), AR (anterior right), AL (anterior left), PR (posterior right), PL (posterior left) tilt directions. EMG signals of trunk (rectus abdominis, external obliques, latissimus dorsi, erector spinae) muscles and leg (rectus femoris, Biceps femoris, Tibialis Anterior, gastrocnemius) muscles were taken out. Root Mean Squire (RMS) values were calculated. The results of this study indicate that different exercise patterns can be applied depending on the exercise types, which are appropriate and necessary to each user. We believe that the human body can be maintained in equilibrium through the interaction between the position and movement execution of the human body, contributing to the improvement of body balance control. Further quantitative data collection and analysis related to the development of various spinal stabilization exercise programs is required. In the near future, we will conduct a study concerning the effects of trunk tilt exercise in active and passive modes on the strength of the tilting muscles and postural balancing ability. Keywords: Trunk stabilization exercise, whole body tilt, active Tilt, passive tilt, EMG
1. Introduction Eighty percent of people in a modern society, who spend most of their time sitting, are experienced back pain; 15% of these people suffered chronic low back pain. Moreover, low back pain creates many problems in regard to the patients’ physical function and moving capacity which limits the patients’ working ability to a great extent, leading to great social economic loss[1-2]. In other words, low back pain is a common disease among humans, and it is one of the main causes of labor losses [3-5]. Spine *Corresponding author. E-mail: [email protected] 0959-2989/14/$27.50 © 2014 – IOS Press and the authors. All rights reserved
246
C.H. Yu et al. / Activity analysis of trunk and leg muscles during whole body tilt exercise
stabilization is defined as a person’s ability to make large or subtle movements of the spinal joints, both consciously and unconsciously [6, 7]. Currently, it is known to be an essential approach for the treatment of patients with low back pain [8- 9]. Spinal stability is believed to play an important role in the prevention and rehabilitation of lumbar spine injury. Therefore, exercises for improving spinal stability are performed widely in sports and rehabilitation. Spinal stabilization exercises include the pelvic tilt exercise, which can activate areas around the spine; naval contraction, where selective abdominal muscle contraction is possible without any movement in the spine; and other exercises using mats, treatment with tables, balls, dumbbells, balance plates, etc. [10-13]. In recent years, isometric exercises have been used to achieve spinal stabilization through the trunk tilt movement in a standing position by using three-dimensional (3D) motion. These exercises contribute to both low back pain reduction and postural balance through strengthening of the trunk muscles. Many studies about these exercises are currently being conducted. Koh et al. [14] analyzed the results regarding the balancing ability of older women and the changes in the thickness of the transversus abdominis muscle and multifidus muscle brought about by an 8week lumbar stabilization exercise program by using a 3D Pegasus system. It is reported that the exercise contributed to positive effects on isometric strength as well as the enhancement of balancing ability. Kim et al. (2011) [15] conducted an experiment for chronic low back pain patients in their 20s by dividing them into 2 groups: a lumbar stabilization exercise group using typical exercise balls, and a group using a 3D air balance system (SNS Korea Co., Korea). After the 2 groups completed the lumbar stabilization training, the visual pain scale scores, limitation on daily life, weight shift angles in 8 directions, and postural disturbance during weight shift were assessed. Then, the effects of these 4 variables on the patients’ postural sway and weight distribution were analyzed. According to the results, in terms of the patients’ muscle balance during active weight shift in the left, right, and diagonal directions, lumbar stabilization exercise using the 3D air balance system was more effective for coordinated movements than that performed using exercise balls. Moreover, 3D exercise was effective for the reduction of posture sway during active weight shift. The 3D isometric exercise equipment examined in existing studies is divided into two movements: a self-generated active movement in the angle and direction steered by the user, and a passive movement generated by the driving of the equipment. However, the exercise equipment used in the current study enables the conversion between active and passive movements. Active and passive movements stimulate different locations of muscle mass and physical characteristics; however, only the effects of 3D exercise equipment on muscle strength were discussed in the research to date regardless the different modes of exercise. Therefore, in this study, we aimed to compare and analyze the differences in trunk muscle strength caused by the body tilt movements with active and passive exercise modes. 2. Experimental methods 2.1. Subjects In this study, eighteen healthy volunteers (18 males, height 176±2.3 cm; mass 69.9±2.7 kg; age 24.7±0.5 years) were investigated. Conforming to the Declaration of Helsinki (1964), written informed consent was obtained from all subjects. None of the subjects had any history of lumber and trunk muscle problems. The investigation was performed in a device for trunk muscle diagnosis and treatment (SpaceBlance 3D, CyberMedic Co. & Chonbuk National Univ., Korea ; Fig.1(a)).
C.H. Yu et al. / Activity analysis of trunk and leg muscles during whole body tilt exercise
247
Fig. 1.(a) 3D dynamic exercise device (SpaceBalance 3D, CyberMedic Co. &Chonbuk National Univ., Korea), (b) Explanation of 8 tilting directions during the trunk tilt exercise modes of the SpaceBalance 3D. (c) Passive tilt mode of the SpaceBalance 3D. (d) Active tilt mode of the SpaceBalance 3D
2.2. System configuration As shown in Fig. 1.(b), the trunk and leg muscles generated by tilting in 8 different directions such as A (anterior), R (right), P (posterior), L (left), AR (anterior right), AL (anterior left), PR (posterior right), PL (posterior left) were measured during the trunk tilt exercise modes of a 3D dynamic exercise device. This device applies forces on the trunk by tilting the whole body from a neutral upright position. Subjects are fixed at their feet and hips, but the trunk remains unsupported. During the different tilt positions, the subject has to simply stabilize his or her upper body in the body axis. For this investigation, subjects held their arms crossed against their chests. Exact body and arm positioning throughout the whole investigation was controlled by the examiner. This 3D dynamic equipment was capable of moving 100 degrees in the A-P direction, 180 degrees in the L-R direction, 100 degrees in the AR- PL direction and 100 degrees in the AL-PR direction since it can be rotated in 3D space. For the recording of the EMG signals, an 8-channel surface EMG system was used (Bignoli system, Delsys. Inc., USA). All raw EMG signals were band pass-filtered between 6 to 400 Hz and amplified. The sampling rate was 1000 Hz and the signals were converted from an analogue voltage to a digital signal at 1000Hz (A/D conversion) before being transformed into a personal computer. The electrode was attached after removing the keratinous skin layer with sterilization alcohol to reduce the skin resistance against the surface EMG signals. We measured trunk (rectus abdominis, external obliques, latissimus dorsi, erector spinae) muscles and leg (rectus femoris, Biceps femoris, Tibialis Anterior, gastrocnemius) muscles during these exercise. Root mean squire (RMS) values were used for the analysis method. RMS values were calculated to quantify the amplitude of the EMG signals. 2.3. Experimental equipment and procedures This device (Space Blance 3D, CyberMedic Co. &Chonbuk National Univ., Korea) has active and passive tilt modes according to the driven approach in Fig. 1(c), and (d). This device is divided into two exercise modes: a self-generated active movement in the angle and direction steered by the user (active tilt mode), and a passive movement generated by the driving of the equipment (passive tilt
248
C.H. Yu et al. / Activity analysis of trunk and leg muscles during whole body tilt exercise
mode). Our experimental procedures were conducted by explaining the analysis of trunk and leg muscle activities generated by 30 degrees in 8 tilting directions with both the active and passive tilt modes. The applied tilting directions are A (anterior), R (right), P (posterior), L (left), AR (anterior right), AL (anterior left), PR (posterior right), and PL (posterior left).The subject then maintained their COG (center of gravity) to the appointed 8 tilting directions twice for 10 sec, respectively. 20 seconds of relaxation was allotted during targeting change. To recover the muscular strength, 20 minutes of relaxation was allotted between the active tile and passive tile modes. As shown in Fig. 2, the electrode was attached after removing the keratinous skin layer with sterilization alcohol to reduce the skin resistance against the surface EMG signals. The trunk (rectus abdominis, external obliques, latissimus dorsi, erector spinae) muscles and leg (rectus femoris, Biceps femoris, Tibialis Anterior, gastrocnemius) muscles were measured during these exercise.
Fig. 2.Muscle measured in upper and lower limbs for verifying muscular activities
2.4. Data analysis Data analysis was completed using the statistical software program SPSS PASW statistics 18(SPSS Inc., Chicago, IL, USA) for Windows Ver. 12.0. The Kolmogorov-Smirnov test (K–S test) was used to evaluate the differences in EMG activity between the active mode and passive mode for changes in the measured parameters. A P value of less than 0.05 was considered statistically significant. 3. Results 3.1. Analysis of trunk muscle activities Figures 3–6 illustrate trunk muscle activities according to the active and passive movements generated by tilting in 8 directions. The y-axes represent Root Mean Square (RMS) values converted from the electromyography (EMG) data, and the x-axes indicate the 8 directions. Figure 3 represents the RMS values of the left and right sides of the rectus abdominis. In the case of the left rectus abdominis, muscle activity maintaining the active tilt mode in the P and PL directions was higher than that in the passive tilt mode. In the case of the right rectus abdominis, muscle activity in the active tilt mode in the P and PR directions was significantly higher. Rectus abdominis muscle activities during the active and passive tilt modes demonstrated significantly higher RMS values in the
C.H. Yu et al. / Activity analysis of trunk and leg muscles during whole body tilt exercise
249
P direction than those in the A direction, regardless whether the muscle was in the active or passive mode. Figure 4 illustrates the RMS values of the left and right external oblique. In the case of the left external oblique, maintaining the passive tilt mode in the AR and AL directions resulted in significantly higher values, whereas in the case of the right external oblique, maintaining the passive tilt mode in the PL direction resulted in higher values (p < 0.05). In terms of external oblique muscle activity in both the active and passive tilt modes by direction, tilting in the PR and R directions caused much higher values of muscle activity than tilting in the PL and L directions in the case of the left muscle. In contrast, in the case of the right muscle, the opposite tendency was observed: tilting in the PL and L directions caused much higher values than tilting in the PR and R directions.
Fig. 3.Rectus abdominis of RMS in passive and active tilt training in eight directions
Fig. 4.External oblique of RMS in passive and active tilt training in eight directions
According to the RMS values of the left and right latissimus dorsi shown in Figure 5, muscle activities in the passive tilt mode showed higher values in all directions except for the A and PL directions in the case of the left latissimus dorsi. Muscle activities in the passive tilt mode were higher in the P, L, and AL directions in the case of the right latissimus dorsi. However, there were no significant differences in the muscle activities in different directions.
250
C.H. Yu et al. / Activity analysis of trunk and leg muscles during whole body tilt exercise
Fig. 5.Latissimus dorsi of RMS in passive and active tilt training in eight directions
Fig. 6.Erector spinae of RMS in passive and active tilt training in eight directions
3.2. Analysis of leg muscle activities As shown in Fig. 7, there was no significant tilting mode-related difference in the muscle activities of the left rectus femoris. In the case of the right rectus femoris, the muscle activities generated by maintaining the passive tilting mode in the PR and PL directions were significantly lower than those generated by maintaining the active tilting mode in the same directions (p
