Earticle

This study aims to identify the effects of an isometric trunk exercise program on muscle endurance and balance ability in young adults. Fourteen young adults volunteered to participate in this study. Isometric muscle endurance tests (trunk curl in supine, hyperextension of trunk in prone, and arm-supporting side bridge) and one-leg standing test were used to measure muscle endurance and balance of subjects. Isometric trunk exercises were performed for 30 minutes, twice per week for 6 weeks (a total of 12 sessions), including upper and lower abdominal drawing, abdominal bracing, posterior pelvic tilting, supine bridge exercise, and alternating raising of limbs in quadruped position. After the intervention, significant improvements were found for all items of muscle endurance and balance (p<.05). These findings suggest that an isometric trunk exercise program might be favorably used to enhance muscle endurance if the trunk and balance in young adults. Further studies need to support our findings.

PURPOSE: The initiation of the trunk muscles in stroke patients is delayed because the muscles involved in reach arm are activated earlier than the trunk muscles. The objective of this study was to examine the effects of mobility, balance, and trunk control ability through selective trunk exercise (STE) in patients with chronic stroke. METHODS: A randomized pre-test and post-test control group design was initially used, with subjects randomly assigned to the STE group (n=15) and a control group (n=14). All groups underwent physical therapy based on the neuro-developmental therapy (NDT) for 30 minutes a day, five times per week for four weeks. Additionally, the STE group did the trunk exercise for 30 minutes a day, three times per week for four weeks. The timed up and go test (TUG), Berg balance scale (BBS), and trunk impairment scale (TIS) were used for assessment. RESULTS: The scores of the TUG, BBS, dynamic sitting balance subscale, and coordination subscale of TIS improved significantly in both groups but the improvement was more pronounced in the STE group (p<.05). This study showed a large effect on the scores of the TIS coordination subscale (d=.93) (p<.05), TIS dynamic balance subscale (d=.81) (p<.05), TUG (d=.75) (p<.05), and BBS (d=.73) (p<.05). CONCLUSION: The combined STE and NDT program showed improvements in measures of mobility, balance, and trunk control in chronic stroke patients. These results suggest that STE should be considered to be included in the treatment program for patients with chronic stroke.

Objective To investigate the changes of activation of the abdominal muscles depending on exercise angles and whether the activation of rectus abdominis differs according to the location, during curl up and leg raise exercises, by measuring the thickness ratio of abdominal muscles using ultrasonography. Methods We examined 30 normal adults without musculoskeletal problems. Muscle thickness was measured in the upper rectus abdominis (URA), lower rectus abdominis (LRA), obliquus externus (EO), obliquus internus (IO), and transversus abdominis (TrA), at pre-determined angles (30o, 60o, 90o) and additionally at the resting angle (0o). Muscle thickness ratio was calculated by dividing the resting (0o) thickness for each angle, and was used as reflection of muscle activity. Results The muscle thickness ratio was significantly different depending on the angles in URA and LRA. For curl up?URA p=0 (30o<60o), p=0 (60o>90o), p=0.44 (30o<90o) and LRA p=0.01 (30o<60o), p=0 (60o>90)o, p=0.44 (30o>90o), respectively, by one-way ANOVA test?and for leg raise?URA p=0 (30o<60o), p=0 (60o<90o), p=0 (30o<90o) and LRA p=0.01 (30o<60o), p=0 (60o<90o), p=0 (30o<90o), respectively, by one-way ANOVA test?exercises, but not in the lateral abdominal muscles (EO, IO, and TrA). Also, there was no significant difference in the muscle thickness ratio of URA and LRA during both exercises. In the aspect of muscle activity, there was significant difference in the activation of RA muscle by selected angles, but not according to location during both exercises. Conclusion According to this study, exercise angle is thought to be an important contributing factor for strengthening of RA muscle; however, both the exercises are thought to have no property of strengthening RA muscle selectively based on the location.

This study examined the effects of trunk stabilization exercise on balance and trunk control in children with spastic diplegia. Four children with ambulatory spastic diplegia participated in the trunk stabilization exercise program using a Both Sides Utilized (BOSU) ball, 30 minutes a day, two times a week for eight weeks. Outcome variables included the pediatric balance scale, trunk control movement scale and multifidus thickness using ultrasound image. After trunk stabilization exercise, there was statistically no significant improvement in pediatric balance scale, trunk control movement scale and multifidus thickness. However, individual outcomes were observed with some positive changes. Balance, trunk control movement, and thickness of multifidus were found to be improved. Trunk stabilization exercise using a BOSU ball could improve trunk control and increase the thickness of multifidus in children with spastic diplegia. Further investigation is needed to evaluate subjects according to type of cerebral palsy and to understand the relationship between postural control and gait.

Purpose: The present study was to investigate effects of scapular position and pain on a trunk stabilization exercise with gym ball for patients with arthroscopic rotator cuff repair. Methods: Subjects were patients after 2 weeks of rotator cuff repairs. Subjects were randomly assigned to conservative treatment group (CTG, n=10) or trunk stabilization with gym ball group (SBG, n=10), and participated one of those groups for 2 weeks. Measurements about pain and scapular position were assessed in before and after treatment programs. Results: Pain reduced in both rest and night in SBG compared to CTG. In the case of scapular position, decreased scapular retraction (increased protraction) was found in CTG and vice versa in SBG. Reduced scapular anterior tilting was also found on SBG. Conclusion: The present study showed that early performed trunk stabilization with gym ball could bring a scapular alignment that increases subacromial space and reduces pain. This suggests early trunk stabilization with gym ball programs to restore shoulder functions for patients with rotator cuff repair.

Purpose: This study aimed to investigate the effect of active vibration exercise on trunk muscle activity, balance, and activities of daily living in patients with chronic stroke. Methods: Twenty-four patients with chronic stroke were randomly assigned to an experimental (n=12) or a control (n=12) group. The experimental group performed an active vibration exercise workout for 20 minutes a day five times a week for 4 weeks using a flexi-bar. Trunk muscle activity was measured using surface electromyography. Balance was measured using the Berg balance scale. Activities of daily living were measured using the functional independence measure. Results: The intragroup comparison showed significant differences in the rectus abdominis, internal oblique, and external oblique muscle activity values, Berg balance scale score, and functional independence measurement values in the experimental group. The intergroup comparison showed that differences in the rectus abdominis and internal oblique external oblique muscle values, Berg balance scale score, and functional independence measurement value for the experimental group were significantly related to those in the control group. Conclusion: Based on these results, this study proved that the active vibration exercise effectively improved trunk muscle activity, balance, and activities of daily living in patients with chronic stroke.

Purpose: This study was conducted to evaluate the effects of neck and trunk stabilization exercise on static and dynamic balance in older adults. Methods: A total of 30 older adults participated in this study. Participants were randomly assigned to the neck and trunk stabilization exercise group (NTSG) (n=15) or the trunk stabilization exercise group (TSG) (n=15). The NTSG performed a trunk stabilization exercise added to a neck stabilization exercise that included biofeedback. Both groups received training for 30 minutes per day three times per week for eight weeks. The anterior, posterior limit of stability and sway length was used to measure static balance ability, while the timed up and go (TUG) test was used to measure dynamic balance ability. Results: Participants showed significant differences in sway length, anterior limit of stability, posterior limit of stability, and the results of the TUG test between their pre- and post mediation evaluations (p<0.05). The NTSG showed a more significant increase than the TSG (p<0.05). Conclusion: According to the results of this study, both exercises effectively improved static and dynamic balance ability. However, the neck and trunk stabilization exercise is more efficient for increasing the balance ability of older adults.

Purpose: The aim of this study was to identify the effects of Pilates mat exercise may improve trunk muscle thickness and balance in healthy adults. Methods: Eighteen healthy adults participated in this study. They were randomly assigned to one of two groups: Pilates mat exercise group (n=9) and the control group (n=9). Subjects in Pilates mat exercise group performed the exercises three days per week for 6 weeks, which consisted of warm up, main workout, and cool down. Trunk muscle thickness of the rectus abdominis (RA), internal oblique (IO), external oblique (EO), transverse abdominis (TrA), multifidus (MF), and erector spine (ES) were measured using an ultrasonography. Balance ability was evaluated using Romberg test and limits of stability (LOS). Measurements were performed before training, 3 weeks after training, and 6 weeks after training. Results: There was a significant difference of RA, EO, IO, MF, and ES according to the main effect of time (p<0.05). There was a significant difference of EO, MF, ES, Romberg, and LOS according to interaction effect between the time and group (p<0.05). There was a significant difference only for LOS according to the main effect of the group (p<0.05). Conclusion: Pilates mat exercise did increase trunk muscle thickness and balance. However, the effect with respect to trunk thickness was limited. Pilates mat exercise appears to be more effective in improving muscles related to trunk extension and balance.

Background: Prolonged sitting, low physical activity, and trunk muscle weakness in university students increase the risk of low back pain (LBP), which can alter gait and lower-limb muscle activation. Purpose: To investigate the effects of a 4-week trunk stabilization exercise program on spatiotemporal gait parameters, lower-limb muscle activation, and functional disability in university students with LBP. Study design: Single-group pre-post intervention study. Methods: Twenty-seven university students with LBP performed 16 trunk stabilization exercises once daily for 40 minutes, 5 days per week, for 4 weeks. Gait was assessed using a pressure-sensing walkway to obtain stance phase, single-limb stance, and stride length. Surface electromyography recorded activation of six lower-limb muscles during gait and was normalized to maximum voluntary isometric contraction. Functional disability was evaluated using the Korean version of the Oswestry Disability Index (K-ODI). Pre-post differences were analyzed using repeated measures ANOVA. Results: Stance phase duration significantly decreased, whereas single-limb stance and stride length significantly increased (p<.01). Soleus and biceps femoris activity increased (p<.01), while rectus femoris, tibialis anterior, and popliteus activity decreased (p<.05); gastrocnemius showed a non-significant increase. K-ODI scores decreased from 29.40+/-5.60 to 23.62+/-5.01 (p<.01). Conclusions: A 4-week trunk stabilization program improved gait efficiency, reorganized lower-limb neuromuscular activation, and reduced functional disability in young adults with LBP. Trunk stabilization may be used as a practical, non-invasive intervention in university populations.

Purpose: This study examined the effects of a four-week trunk stabilization exercise (TSE) program on the gait parameters, lower-limb joint motion, and pain intensity of university students with low back pain (LBP). Methods: Twenty-seven students with moderate disability levels (Korean Oswestry Disability Index: 21-40%) participated. The TSE program consisted of 16 stabilization exercises performed for 40 minutes per day, five times per week, using video-guided self-training. The gait parameters, including the step length and step width, were assessed using a pressure-sensing walkway system. The lower-limb joint angles during the swing phase were analyzed using smartphone video recordings processed in ImageJ, focusing on the hip flexion, knee flexion, and ankle dorsiflexion peaks. The pain intensity was measured using the Visual Analogue Scale (VAS). All measurements were conducted under identical pre- and post-intervention conditions using a standardized fatigue protocol. The pre-post comparisons were analyzed using paired t-tests with effect sizes (Cohen's d). Results: The step length increased significantly, whereas the step width decreased after the intervention, indicating improved gait efficiency and mediolateral stability. Hip flexion during the swing phase increased significantly, while the changes in knee and ankle joint angles were not statistically significant. The pain intensity (VAS) showed a significant reduction. The effect sizes ranged from small to large, with the largest effects observed for the step length and pain reduction. Conclusion: The four-week TSE program effectively improved the gait symmetry, enhanced proximal joint mobility, and reduced pain in university students with LBP. These findings suggest that stabilization-based exercises are an efficient and accessible intervention for restoring neuromuscular control and may help prevent chronicity.

Purpose: We investigated to identify the effect of robo-horseback riding exercise (RHRE) on trunk muscle activity ratios for patients with low back pain. Methods: Twelve patients with low back pain and twelve healthy adults were recruited for this study. Subjects performed the RHRE with the neutral spine position. The amplitude of electromyography activity was recorded from the selected trunk muscles (internal oblique [IO], rectus abdominis [RA], multifidus [MF], the thoracic part of the iliocostalis lumborum [ICLT]). The ratios of the relative local muscle activity to the global muscle activity in abdominal and lumbar parts were calculated. Results: There were significant differences in the change values of the IO/RA and the MF/ICLT between low back pain (LBP) patients and healthy adults. The IO/RA ratio and the MF/ICLT ratio showed significant increase in LBP patients after training. Conclusion: The RHRE improved the trunk muscle activity ratio in patients with low back pain. The information presented here is important for investigators who use lumbar stabilization exercises as a rehabilitation exercise.

Background: Scapular downward rotation syndrome (SDRS) is a common scapular alignment impairment that causes insufficient upward rotation and muscle imbalance, shortened levator scapulae (LS) and rhomboid, and lengthened serratus anterior (SA) and trapezius. A modified shrug exercise (MSE), performing a shrug exercise with the shoulders at $150^{\circ}$ abduction, is known as an effective exercise to increase scapular stabilizer muscle activation. Previous studies revealed that scapular exercise are more effective when combined with trunk stabilization exercises in decreasing scapular winging and increasing scapular stabilizer muscle activation. Objects: The purpose of our study was to clarify the effect of MSE with or without trunk stabilization exercises in subjects with SDRS. Methods: Eighteen volunteer subjects (male=10, female=8) with SDRS were recruited for this experiment. All subjects performed MSE under 3 different conditions: (1) MSE, (2) MSE with an abdominal draw-in maneuver (ADIM), and (3) MSE with an abdominal expansion maneuver (AEM). The muscle thickness of the lower trapezius (LT) and the SA were measured using an ultrasonography in each condition. Electromyography (EMG) data were collected from the LT, LS, SA, and upper trapezius (UT) muscle activities. Data were statistically analysed using one-way repeated analysis of variance at a significance level of .05. Results: The muscle thickness of the LT and the SA were the significant different in the MSE, MSE with ADIM (MSE+ADIM) and MSE with AEM (MSE+AEM) conditions (p<.05) In both LT and SA, the order of thick muscle thickness was MSE+AEM, MSE+ADIM, and MSE alone. No significant differences were found in the EMG activities of the SA, UT, LS, and LT in all condition. Conclusion: In conclusion, MSE is more beneficial to people with SDRS when combined with trunk stabilization exercises by increased thickness of scapular stabilizer muscles.

Objective: To investigate the effect of performing three different bridge exercise conditions on the activities of four different muscles using surface electromyography (sEMG) in healthy young adults. Design: Cross-sectional study. Methods: A total of 20 healthy young adults (10 males, 10 females) voluntarily participated in this study. All subjects randomly performed three different bridge conditions as follows: general bridge exercise, isometric hip abduction (IHAB) with a blue Theraband (Hygenic Corp., USA), and isometric hip adduction (IHAD) with a Swiss ball (Hygenic Corp.). The muscle activities of bilateral erector spinae (ES), gluteus maximus (GM), biceps femoris (BF), and external oblique (EO) muscles during the bridge exercises were measured using sEMG. Subjects performed each of the three bridge conditions three times in random order and mean values were obtained. Results: For bilateral ES and BF, there was a significant increase in muscle activity in the IHAD condition compared to the general bridge and IHAB condition (p<0.05). For bilateral GM, there was a significant increase in muscle activity in the IHAB condition compared to the general bridge condition (p<0.05) and there was a significant increase in muscle activity in the IHAB condition compared to IHAD condition (p<0.05). For left EO, a significant increase was observed in the IHAD condition compared to the general bridge condition (p<0.05). Conclusions: ES and BF muscle activity increases were observed with hip adduction and increased GM activity was observed with hip abduction. These findings may be applicable within the clinical field for selective trunk and lower extremity muscle activation and advanced rehabilitation purposes.

PURPOSE: Bridge exercises are broadly used to develop trunk co-activation patterns that promote spine stability. This study was to analyze the trunk muscle activity during bridge exercise with various shoulder support surface(stable, sling, Swiss ball). METHODS: The subjects were 20 healthy subjects in their twenties. Subjects were performed bridge exercise on 4 different shoulder support surfaces using stable and labile instruments. 1) Bridge exercise on a stable surface. 2) Bridge exercise with their shoulder on a stable bench. 3) Bridge exercise with their shoulder on a sling. 4) Bridge exercise with their shoulder on a Swiss ball. Rectus abdominis, erector spinae, internal oblique, external oblique muscle activities were measured using electromyography. RESULTS: There were significant differences in RA, EO muscles between performing each of the 4 exercises(p<.05). RA and EO was recorded the highest activity during the bridge exercise with their shoulder on a sling. The lowest activity was recorded during conventional supine bridge on a stable surface. There were no differences found for the EO/RA and IO/RA ratio. The EO/RA and IO/RA ratio was the highest in the bridge exercise with their shoulders resting on a stable bench. CONCLUSION: These findings suggest that change of shoulder support surface during bridge exercise may be useful for enhancing the trunk stability.

Purpose: This study examined the effects of trunk side shift exercise on the Cobb's angle. Methods: Fifty-eight subjects (control group=30, scoliosis group=28) were enrolled in this study. The idiopathic scoliosis groups were divided randomly into two groups, a side shift exercise (SSE) group, and a trunk stabilization exercise (TSE) group. The SSE group performed side shift exercise on the developed chair training for eight weeks. The TSE group performed trunk stabilization exercise. A oneway ANOVA test was carried out to compare the results within the idiopathic scoliosis patient group before and after the exercises based on the different exercise methods. Results: The Cobb's angles were compared among control group and SSE group and TSE group. As a result, there was a significant difference from SSE group and TSE group(p=0.000), but there were no significant differences between the SSE and TSE groups (p=0.085). Conclusion: Side shift exercises are effective in improving the Cobb's angle. Therefore, the use of the side shift exercise chair designed in this study can replace general exercise either at work or during studies. Therefore, this method is easily accessible for busy modern students who are exposed to scoliosis or spinal disorders due to a pattern of inactivity.

Purpose: The purpose of this study was to examine the effect of sling exercise on pain, trunk strength, and balance in patients with chronic low back pain in their 40s and 50s. Methods: Twenty patients with chronic low back pain were divided into two groups, 10 patients in the exercise group using a sling and 10 patients in the waist stabilization exercise group, applying a random assignment, draw-out method, and sling exercise was applied for 50 minutes a day, 3 times a week, for a total of 5 weeks. For data analysis, a corresponding t-test was performed for within-group changes and an independent t-test was performed for inter-group changes, and the significance level was α=0.05. Results: After 5 weeks, there were significant differences in all items of within-group changes, and the inter-group changes after 5 weeks demonstrated significant differences in pain, trunk flexion strength, and balance. Conclusion: The results of this study showed that exercise using a sling had positive effects on pain, trunk flexion strength, and balance changes in chronic low back pain patients. It is suggested that sling exercise can be used as an intervention method for pain reduction and functional improvement of patients with chronic low back pain in clinical practice.

Purpose: This study examined the effect of vibration exercise on the thickness of the oblique extrinsic, oblique abdominal, and biceps muscles, which are trunk muscles, targeting children with spastic cerebral palsy. Methods: The participants in this study were 20 children (8 male and 12 female) with cerebral palsy aged 5-10 years. They were classified into two groups using a randomized allocation method, and the trunk muscle thickness was measured using an ultrasound-imaging device before and six weeks after the experiment. A paired t-test was used for the within-group changes, and an independent t-test was used for the inter-group changes. The significance level was set to α=0.05. Results: There was a significant increase in the inter-group change in the experimental group and control group in the intra-group change in the external oblique muscle and internal oblique muscle. After six weeks, there was a significant increase in the experimental group compared to the control group. Conclusion: Vibration exercise had a positive effect on the trunk muscle thickness of children with cerebral palsy. Vibration exercise produced a significant difference in the changes in the trunk muscle thickness in children with cerebral palsy compared to no vibration exercise. These results may provide basic data for future research and as a training method for strengthening the trunk muscles in clinical trials.

Purpose: The purpose of this study was to verify the effect of applying clam exercise on improving trunk control and balance ability in stroke patients. Based on this, we tried to provide clinical information. Methods: In this study, 18 patients with chronic stroke were recruited from a rehabilitation hospital. The patients were divided into two groups: a clam exercise group (9 patients) and a control group (9 patients). After 30 minutes of neuro-development therapy, they performed clam exercise or bridge exercise for 3 weeks, 5 times a week for 30 minutes. A trunk impairment scale (TIS) and a postural assessment scale for stroke patients-trunk control (PASS-TC) were performed to evaluate the subjects' ability to control trunk before and after intervention. Balance ability was measured by Balancia before and after intervention. Results: After the training periods, area 95% COP and weight distribution of the affected side were significantly different from the clam exercise group compared to the control group (p<0.05). Conclusion: Based on the results of this study, in can be seen that the clam exercise is effective in improving the balance ability compared to the bridge exercise. Maintaining the standing posture requires muscle strength of the hip abduction and extension, which is the result of the clam exercise selectively strengthening these muscles. Therefore, if you want to provide intervention to improve the balance of stroke patients, it is recommended to perform a clam exercise.

Purpose: This study examined the effects of curl-up using XCO^® on trunk muscle activation in healthy adults. Methods: This study design was a single-blind randomized controlled trial. Twelve participants were enrolled in this study. The subjects were instructed to perform curl-up exercise in STCU (straight curl-up), LTCU (left twist curl-up), RTCU (right twist curl-up), TWCU (twist curl-up), and PPCU (power push curl-up). Electromyography was used to assess the percent maximal voluntary isometric contraction (%MVIC) of the rectus abdominis (RA), external oblique (EO), internal oblique (IO), and erector spinae (ES) muscles. The data were analyzed using two-way ANOVA with a repeated measure. The statistical significance level was set to α=0.05 Results: The IO showed significant differences in the main effect of the group and the interactions between the group and exercise (p<0.05). In particular, the IO represented the interactions between group and exercise in the RTCU and PPCU (p<0.05). The RA, EO, and ES did not show significant interactions between the group and exercise (p>0.05). The RA, IO, and EO showed significant differences in the main effect of the group (p<0.05). The EO showed a significant difference in the main effect of exercise (p<0.05). Conclusion: These findings suggest that XCO^® can be used to increase the muscle activation of the internal oblique, which is the lumbar stabilizing muscle, when XCO^® is combined in the curl-up exercise with rotation. In the future, research on the intensity, frequency, and duration of XCO^® exercise will be needed according to the individual characteristics and preferences.

ABSTRACT Background Although there are many exercises to selectively strengthen the thoracic extensor, general trunk extensor strengthening exercises lead to pain and excessive lumbar extension. Purpose We investigated the most effective exercise among three thoracic extensor strengthening exercises (active prone thoracic extension, active prone thoracic hyper-extension, and active sitting thoracic extension) based on selective activity of the thoracic spine extensors. Study design Comparative, repeated measures design. Methods Sixteen healthy participants performed three thoracic extensor strengthening exercises. Electromyograph (EMG) activity was measured in the longissimus thoracis (LT), iliocostalis thoracis (ICT), and iliocostalis lumborum (ICL) muscles. Results The ICT/ICL and LT/ICL composition ratios were greatest in active sitting thoracic extension compared to other exercises. Conclusions We recommend active sitting thoracic extension exercise for selective strengthening of the thoracic spine extensor.