Background: As ways to optimize the mobilization of postural stability muscles for sitting up motions, arm reaching motions and head raising motions have important effects. Objectives: This study was conducted to investigate the effects of reaching to sit-up training on the trunk muscle activity, postural ability, and balance ability of patients with hemiplegia due to stroke. Design: Randomized controlled trial. Methods: This study was conducted with 18 stroke patients who met the selection criteria divided into two groups: a study group of 9 patents and a control group of 9 patients. The study group carried out reaching to sit-up training, which can promote trunk muscles and improve control through trunk interactions. The control group received general physical therapy intervention Results: The activity of the trunk muscle was significantly different before and after intervention in study and control group. The functional reaching test showed significant changes in both the study group and the control group. The timed up and go test showed a significant change in the study group. Conclusion: Reaching to sit-up training for 4 weeks showed increases in trunk muscle activity in stroke patients and was effective in improving balance ability.

Background: Various functional tests such as upper quarter Y-balance test (UQYBT) are used to evaluate shoulder stability and mobility in clinical or sports fields. Previous studies have been conducted to determine the correlation between the scapular or trunk muscle and UQYBT. However, the correlation between UQYBT and hip flexor, which can be considered as a core muscle, has not been confirmed. Objects: To verify the relationship between the UQYBT and scapular muscle (scapular protractor and lower trapezius [LT]), trunk muscle, and hip flexor strengths in healthy male participants. Methods: A total of 37 healthy male participants were recruited and underwent UQYBT in the push-up posture. The isometric strength of the scapular protractor, LT, trunk flexor and extensor, and hip flexors were measured using a smart KEMA strength sensor (KOREATECH Inc.). Results: The superolateral direction of the UQYBT was moderately to strongly related to trunk extensor (r = 0.443, p < 0.01), scapular protractor (r = 0.412, p < 0.05), LT (r = 0.436, p < 0.01), and both sides of the hip flexors (supporting-side: r = 0.669, p < 0.01; non-supporting- side: r = 0.641, p < 0.01). The inferolateral direction of the UQYBT was moderately related to the scapular protractor (r = 0.429, p < 0.01), LT (r = 0.511, p < 0.01), and both sides of hip flexors (supporting-side: r = 0.481, p < 0.01; non-supporting-side: r = 0.521, p < 0.01). The medial direction of the UQYBT was moderately to strongly related with the scapular protractor (r = 0.522, p < 0.01), LT (r = 0.541, p < 0.01), and both sides of hip flexors (supporting-side: r = 0.605, p < 0.01; non-supporting-side: r = 0.561, p < 0.01). Conclusion: This study showed that the strength of the scapular muscles, trunk muscles, and hip flexor muscles correlated to the UQYBT. Therefore, the strength of not only the scapular and trunk muscles but also the hip flexor muscles should be considered to improve the UQYBT.

Background: The Trunk Stabilization Exercise and Respiratory Muscle Exercise may help address the complex biomechanical and neuromuscular issues that contribute to shoulder joint disorders and can help improve patient outcomes in terms of pain relief, range of motion, and functional ability. Objectives: To investigated the effects of conventional physical therapy, trunk stabilization exercise, and respiratory muscle exercise, on the Range of Motion (ROM), ULF and balance in patients with shoulder joint disorder. Design: A randomized controlled trial. Methods: This study randomly allocated 18 subjects to the control group, 19 to the trunk stabilization exercise group, and 19 to the respiratory muscle exercise group, while all interventions were performed five times a week for four weeks. The result measurement involved the ROM, the upper limb function test (ULT), and balance tests. Results: The respiratory muscles exercise group indicated significant improvement in ROM and balance tests than the trunk stabilization exercise group and control group. Conclusion: The respiratory muscle exercise is a more effective way to improve ROM and balance ability than trunk stabilization exercise for patients with shoulder joint disorder.

Background: Core muscle weakness occurs due to trunk asymmetry and spinal malalignment after stroke. Core exercise is being implemented to improve trunk control and sitting position in stroke patients. Objectives: To investigated the effects of core muscle electrical stimulation on trunk control and dynamic balance in stroke patients. Design: Quasi-experimental study. Methods: A total of 30 stroke patients were recruited and divided into two groups: experimental group (core muscle electrical stimulation group) and control group (sham core muscle electrical stimulation group). Trunk impairment scale (TIS) was used to measure trunk control. BioRescue was used to measure sitting dynamic balance. Results: In both groups, all TIS scores and sitting dynamic balance abilities were improved increased significantly after intervention (P<.05). Changes in TIS scores and sitting dynamic balance abilities were significantly greater in the experimental group than the control group (P<.05). Conclusion: It was found that core muscle electrical stimulation can be used as an effective method for trunk control and balance recovery in stroke patients.

Background: Inspiratory muscle training can improve inspiratory strength and endurance through threshold loading. In addition, trunk stabilization exercises can improve trunk strength and respiratory function. Objectives: The purpose of this study is to investigate the effect of application of inspiratory muscle training and trunk stabilization exercise on pulmonary function and inspiratory muscle activation in college students. Design: Randomized controlled trials. Methods: In this study, 24 college students were randomly divided into two groups: inspiratory muscle training and trunk stabilization exercise (experimental group, n=12), and trunk stabilization exercise (control group, n=12). Inspiratory muscle activity was measured using a surface electromyography. Pulmonary function was measured using a spirometer and a peak expiratory flow meter. Results: In the experimental group, the muscle activity of both upper trapezius and latissimus dorsi muscles increased significantly after the intervention. In the experimental group, both upper trapezius muscle activity was significantly increased than in the control group. In the experimental group, all the pulmonary function significantly increased after the intervention. Conclusion: In this study, when the inspiratory muscle training was additionally applied to the trunk stabilization exercise in college students in their twenty, it was possible to improve the inspiratory muscle activity and pulmonary function.

Background: Low back pain (LBP) is a representative disease, and LBP is characterized by muscle dysfunction that provides stability to the lumbar spine. This causes physical functional problems such as decreased posture control ability by reducing the muscular endurance and balance of the lumbar spine. Pelvic compression using instruments, which has been used during recent stabilization exercises, focuses on the anterior superior iliac spine of the pelvis and puts pressure on the sacroiliac joint during exercise, making the pelvis more symmetrical and stable. Currently, research has been actively conducted on the use of pelvic compression belts and non-elastic pelvic belts; however, few studies have conducted research on the application effect of pelvic compression using instruments. Objects: This study aimed to investigate whether there is a difference in trunk muscular endurance and dynamic and static balance ability levels by applying pelvic stabilization through a pelvic compression device between the LBP group and the non-LBP group. Methods: Thirty-nine subjects currently enrolled in Daejeon University were divided into 20 subjects with LBP group and 19 subjects without LBP (NLBP group), and the groups were compared with and without pelvic compression. The trunk muscular endurance test was performed with 4 movements, the dynamic balance test was performed using a Y-balance test, and the static balance test was performed using a Wii balance board. Results: There was a significant difference the LBP group and the NLBP group after pelvic compression was applied to all tests (p < 0.05). In the static and dynamic balance ability test after pelvic compression was applied, there was a significant difference in the LBP group than in the NLBP group (p < 0.05). Conclusion: These results show that pelvic compression using instruments has a positive effect on both those with and without LBP and that it has a greater impact on balance ability when applied to those with LBP.

Background: Bird dog exercise (BDE) is one of the lumbar stabilization exercises that rehabilitate low back pain by co-contraction of the local and global muscles. Previous studies have reported the effect of various type of BDEs (for example, practicing the exercises on various surfaces and changing the limb movement) for muscle co-contraction. Objects: This study aimed to investigate the effect of knee joint flexion position of the raised lower limb on abdominal and back muscle activity during BDE in patients with chronic low back pain (CLBP). Methods: Thirteen males participated in this study (age: 32.54 ± 4.48 years, height: 177.38 ± 7.17 cm). Surface electromyographic (SEMG) data of the internal abdominal oblique (IO), external abdominal oblique (EO), lumbar multifidus (MF), and thoracic part of the iliocostalis lumborum (ICLT) were collected in two knee joint flexion positions (90° flexion versus 0° flexion) during BDE. The SEMG data were expressed as a percentage of root mean square mean values obtained in the maximal voluntary isometric contraction. Results: Greater muscle activity of the IO (p = 0.001), MF (p = 0.009), and ICLT (p = 0.021) of the raised lower limb side and the EO (p = 0.001) and MF (p = 0.009) of the contralateral side were demonstrated in the knee joint flexion position compared to the knee joint extension position. Greater local/global activity ratios of the abdominal muscle (i.e., IO and EO) of the raised lower limb (p = 0.002) and the back muscle (i.e., MF and ICLT) of the contralateral side (p = 0.028) were also noted in the knee joint flexion position. Conclusion: BDE with a knee joint flexion position might be recommended as an alternative lumbar stabilization exercise to enhance muscle activity in both the raised lower limb and the contralateral sides of the trunk for individuals with CLBP

Background: Lunge exercises are lower extremity rehabilitation and strengthening exercises for patients and athletes. Most studies have shown the effectiveness of the forward and backward lunge exercises for treating patellofemoral pain and anterior cruciate ligament injuries (by increasing lower extremity muscle activity) and improving kinematics. Objects: However, it is not known how the two different lunge movements affect trunk muscle activities in healthy individuals. The purpose of this study was to investigate the electromyographic activity of the rectus abdominis and erector spinae muscles during forward and backward lunge exercises in healthy participants. Methods: Twelve healthy participants were recruited. Electromyographic activity of the rectus abdominis and erector spinae was recorded using surface electrodes during forward and backward lunges, and subsequently normalized to the respective reference voluntary isometric contractions of each muscle. Results: Activity of the erector spinae was significantly higher than that of the rectus abdominis during all stages of the backward lunge (p < 0.05). The activity of the erector spinae was significantly greater during the backward than forward lunge at all stages (p < 0.05). Conclusion: Backward lunging is better able to enhance trunk motor control and activate the erector spinae muscles.

Background: Stroke patients have weak trunk muscle strength due to brain injury, so a single type of exercise is advised for restoring functionality. However, even after intervention, the problem still lies and it is suggested that another intervention method should be applied with exercise in order to deal with such problem. Objectives: To Investigate the effect of bridge exercise combined with functional electrical stimulation (FES) on trunk muscle activity and balance in stroke patients. Design: Randomized controlled trial. Methods: From July to August 2020, twenty stroke patients was sampled, ten patients who mediated bridge exercises combined with functional electrical stimulation were assigned to experiment group I, and ten patients who mediated general bridge exercises were assigned to experiment groupⅡ. For the pre-test, using surface EMG were measured paralyzed rectus abdominis, erector spinae, transverse abdominis/internal oblique muscle activity, and using trunk impairment scale were measured balance. In order to find out immediate effect after intervention, post-test was measured immediately same way pre-test. Results: Change in balance didn’t show significant difference within and between groups, but muscle activity of trunk was significant difference rectus abdominis and erector spinae within groups I (P<.01), also between groups was significant difference (P<.05). Conclusion: Bridge exercise combined with FES could improve trunk function more effectively than general bridge exercise due to physiological effect of functional electrical stimulation.

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: The flexion-relaxation phenomenon (FRP) refers to a sudden onset of activity in the erector spinae muscles that recedes or fades during full forward flexion of the trunk. Lumbar spine and hip flexion are associated with many daily physical activities that also impact trunk flexion. Shorter hamstring muscles result in a reduction of pelvic mobility that eventually culminates in low back pain (LBP). Many studies have explored the FRP in relation to LBP. However, few studies have investigated the influence of hamstring muscle length on the FRP in relation to the erector spinae muscles during trunk flexion. Objects: This study aimed to investigate the influence of hamstring muscle length on the FRP in relation to the erector spinae muscles during trunk flexion. Methods: Thirty subjects were divided into three groups according to hamstring length measured through an active knee extension test. The 30 participants consisted of 10 subjects who had a popliteal angle of 20˚ or less (Group 1), 10 subjects who had a popliteal angle of 21˚–39˚ (Group 2), and 10 subjects who had a popliteal angle of 40˚ or more (Group 3). A one-way analysis of variance was used to compare the difference in muscle activity of the erector spinae muscles during trunk flexion. Results: The subjects with a shorter hamstring length had significantly higher muscle activity in their erector spinae muscles during trunk flexion and full trunk flexion (p < 0.05). The subjects with a shorter hamstring length also had a significantly higher flexion-relaxation ratio (p < 0.05). Conclusion: The results of this study demonstrate that differences in hamstring muscle length can influence the FRP in relation to the erector spinae muscles. This finding suggests that the shortening of the hamstring might be associated with LBP.

본 연구의 목적은 무릎 푸시업 플러스 동작 시 슬링과 진동기 적용이 체간 근육의 근활성도 변화에 미치는 영향에 대해 알아보는 것이었다. 본 연구의 대상자는 신체 건강한 20대 남성 10명을 대상으로 실시하였고(연령, 23.00±0.45 세; 신장, 176.60±1.64 cm; 체중, 67.50±1.22 kg; 신체질량지수, 21.65±0.34 kg/m2), 3가지의 기본 무릎 푸시업 플러스 동작, 슬링을 적용한 무릎 푸시업 플러스 동작, 및 진동기를 적용한 무릎 푸시업 플러스 동작을 수행하였으며, 표면전극 부착 부위는 체간 근육의 오른쪽 상부 승모근, 대흉근, 전거근, 복직근, 및 외복사근으로 설정하였다. 본 연구의 결과는 다음과 같다. 승모근, 대흉근, 전거근, 복직근, 및 외복사근의 근활성도는 진동기를 적용한 무릎 푸시업 플러스 동작 시 통계적으 로 가장 높게 나타났다(p<.001). 따라서 본 연구의 결과는 향후 무릎 푸시업 플러스 동작 적용 시 효과적인 체간 근육을 강화시키기 위한 트레이닝 프로그램의 기초자료가 될 것으로 기대된다.

Background: Ipsilateral pelvic elevation has been reported as a common compensatory movement during side-lying hip abduction. It has been reported that pelvic elevation inhibits sufficient contraction of gluteus medius. However, few studies have identified the effects of controlled pelvic elevation on the trunk and hip muscles. Objective: To examine the effects of controlled pelvic elevation using visual biofeedback on the muscle activity of the trunk and hip muscles. Design: Crossover study. Methods: Twelve healthy males performed side-lying hip abduction exercises with and without visual biofeedback for pelvic elevation. Electromyography (EMG) activities of the gluteus medius, quadratus lumborum, and multifidus were analyzed using a wireless EMG system while the ipsilateral pelvic elevation angle was measured using a motion sensor during side-lying hip abduction exercises. Results: EMG activities of the gluteus medius (p = .002), quadratus lumborum (p = .022), and multifidus (p = .020) were significantly increased and ipsilateral pelvic elevation was significantly decreased (p = .001) during side-lying hip abduction with visual biofeedback compared to without visual biofeedback. Conclusions: The results of this study suggest that the application of biofeedback for pelvic motion could improve the trunk and hip muscle activation pattern and decrease compensatory pelvic motion during side-lying hip abduction exercise.

Background: Round shoulder posture, results from excessive flexed posture of the thorax, is defined as a position of scapular protraction, anterior tipping, and downward rotation. However, previous studies have focused on only passive position of the thorax during scapular posterior tilting (SPT) and have not reported on SPT combined with correction of flexed posture. Objects: The aim of this study was to compare effects of SPT and SPT with prone trunk extension (SPT + PTE) on activities of the lower trapezius, serratus anterior, and thoracic erector spinae and degree of posture in subjects with round shoulder and flexed posture. Methods: Fifteen subjects with round shoulder and flexed posture were recruited. The caliper was used to measure the degree of round shoulder and flexed posture. Electromyography was performed to collect data of muscle activities. Paired t-test was used to compare two exercise (α=.05). Results: When SPT + PTE was applied, the degree of round shoulder posture (p=.001) and flexed posture (p=.039) significantly decreased compared with that when SPT was applied. The lower trapezius activity significantly increased in the SPT + PTE condition compared with that in the SPT condition (p=.026). There were no significant differences in serratus anterior activity between SPT + PTE and SPT. The thoracic erector spinae activity significantly increased in the SPT + PTE condition compared with that in the SPT condition (p=.014). Conclusion: SPT + PTE might be one of the effective methods to enhance activities of lower trapezius and thoracic erector spinae, and to reduce round shoulder posture and flexed posture in subjects with round shoulder and flexed posture.

Background: Lumbopelvic stability is highly important for exercise therapy for patients with low back pain and shoulder dysfunction. It can be attained using a pelvic compression belt. Previous studies showed that external pelvic compression (EPC) enhances form closure by reducing sacroiliac joint laxity and selectively strengthens force closure and motor control by reducing the compensatory activity of the stabilizer. In addition, when the pelvic compression belt was placed directly on the anterior superior iliac spine, the laxity of the sacroiliac cephalic joint could be significantly reduced. Objects: This study aimed to compare the effects of EPC on lumbopelvic and shoulder muscle surface electromyography (EMG) activities during push-up plus (PUP) and deadlift (DL) exercise, trunk extensor strength during DL exercise. Methods: Thirty-eight subjects (21 men and 17 women) volunteered to participate in this study. The subjects were instructed to perform PUP and DL with and without the EPC. EMG data were collect from serratus anterior (SA), pectoralis major (PM), erector spinae (ES), and multifidus (MF). Trunk extensor strength were tested in DL exercise. The data were collected during 3 repetitions of all exercise and the mean of root mean square was used for analysis. Results: The EMG activities of the SA and PM were significantly increased in PUP with pelvic compression as compared with PUP without pelvic compression (p<.05). In DL exercise, a significant improvement in trunk extensor strength was observed during DL exercise with pelvic compression (p<.05). Conclusion: The results of this study indicate that lumbopelvic stabilization reinforced with external pelvic compression may be propitious to strengthen PUP in more-active SA and PM muscles. Applying EPC can improve the trunk extensor strength during DL exercise. Our study shows that EPC was beneficial to improve the PUP and DL exercise efficiency.

Background: Improvement of lumbo-pelvic stability can reduce the compensatory action of the quadratus lumborum (QL) and selectively strengthen the gluteus medius (GM) during side-lying hip abduction (SHA). There are abdominal draw-in maneuver (ADIM) and abdominal bracing (AB) as active ways, and pelvic compression belt (PCB) as a passive way to increase of lumbo-pelvic stability. It is necessary to compare how these stabilization methods affect the selective strengthening of the GM. Objects: To investigate the effects of ADIM, AB, and PCB during SHA on the electromyography (EMG) activity of the GM, QL, external oblique (EO) and internal oblique (IO), and the GM/QL EMG activity ratio. Methods: A total of 20 healthy male adults participated in the study. The subjects performed three conditions in side-lying in random order: SHA with ADIM (SHA-ADIM), SHA with AB (SHA-AB), and SHA with PCB (SHA-PCB). To compare the differences among the three conditions, the EMG activities of the GM, QL, EO and IO, and GM/QL EMG activity ratio were analyzed using one-way repeated ANOVA. Results: The EMG activity of the QL was significantly higher in SHA-AB than in SHA-ADIM and SHA-PCB. The GM/QL activity ratio was significantly higher in SHA-PCB than in SHA-ADIM and SHA-AB. In addition, the figure for SHA-ADIM was significantly higher than that for SHA-AB. In the case of the EO, the figure for SHA-AB was significantly higher than corresponding values for the other two conditions. The figure for SHA-ADIM was significantly higher than that for SHA-PCB. The EMG activity of the IO was significantly higher in SHA-AH than in SHA-PCB. Conclusion: It can be suggested that wearing the PCB can more selectively strengthen the GM than to perform ADIM and AB during SHA. In addition, the ADIM can be recommended when there is a need to strengthen abdominal muscles during SHA.

The aim of the present study was to investigate the effects of unilateral shoulder bag weight and heel heights on trunk muscle activities. This study recruited 40 healthy women in their twenties. Electromyography activities of rectus abdominis muscle, external abdominal oblique muscle, internal abdominal oblique muscle and erector spinae muscle during standing position were measured using a surface electromyography system. The overall muscle activities of the trunk muscles were significantly increased in the contralateral trunk muscles (p<.05). Inaddition, the trunk muscles overall activities on the contralateral side without the shoulder bag was positive correlation with the heel height and unilateral shoulder bag weight (p<.05). Both high-heeled wear and unilateral shoulder bags are fashion items that cause asymmetry in the trunk muscles of women in their twenties. These findings suggest that the increase in the weight and heel height of the unilateral shoulder bag in women cause asymmetry of trunk muscle activities.

Background: Patients with chronic stroke often shows decreased trunk muscle activity and trunk performance. To resolve these problems, many trunk stabilizing techniques including the abdominal drawing-in maneuver (ADIM) and the diaphragmatic breathing maneuver (DBM) are used to improve trunk muscle strength. Objects: To compare the effects of the ADIM and the DBM on abdominal muscle thickness, trunk control, and balance in patients with chronic stroke. Methods: This was a randomized controlled trial. Nineteen patients were randomly allocated to the ADIM (n1=10) and DBM (n2=9) groups. The ADIM and DBM techniques were performed three times per week for 4 weeks. The thicknesses of the transversus abdominis (TrA), internal oblique muscle, and external oblique muscles on the paretic and non-paretic sides, Trunk Impairment Scale (TIS) score, and Berg Balance Scale (BBS) score were used to assess changes in motor development after 4 weeks of training. Results: After the training periods, the TrA thickness on the paretic side, TIS score, and BBS score improved significantly in both groups compared to baseline (p<.05). TIS score was significantly greater in the DBM group than in the ADIM group (p<.05). Conclusion: This study demonstrated that ADIM and DBM are beneficial for improving TrA muscle thickness in the paretic side, trunk control, and balance ability. Intergroup comparison revealed that TIS score was significantly improved in the DBM group versus the ADIM group. Thus, DBM may be an effective treatment for low trunk muscle activity and performance in patients with chronic stroke.

The purpose of this study was to investigate the dynamic balance and activity of internal oblique muscle, multifidus muscle, gluteus maximus muscle, biceps femoris muscle during the Y balance test following the wearing of pelvic compression belt. Forty healthy adults were recruited for this test. The dynamic balance score was estimated as the following: (anterior+posteromdial+posterolateral)/(3×leg length)×100. The electromyography signals were measured through %reference voluntary contraction, which was normalized by reference voluntary contraction of Y balance test without wearing the pelvic compression belt. The paired t-test was carried out to compare the dynamic balance score and the activity of the trunk and hip extensor with and without the wearing of pelvic compression belt. The dynamic balance score of the Y balance test when wearing pelvic compression belt was significantly than when measured without wearing the pelvic compression belt (p<.05). The muscle activity of the internal oblique and the multifidus was significantly decreased when wearing pelvic compression belt (p<.05). The muscle activity of the gluteus maximus was significantly increased when wearing pelvic compression belt (p<.05). However, there was no significant difference in hamstring muscle activity, with or without wearing the belt (p>.05). In conclusion, this study shows that the wearing of pelvic compression belt affects trunk muscle and hip extensor muscle activity related to the pelvic mobility and stability and increases dynamic balance and also contributes to the stabilization of the external pelvic stabilization.

The aim of this study was to investigate the effects of different postural correction in the electromyographic (EMG) activity of the trunk and hip muscles during bridging exercises. Twenty-four healthy subjects volunteered for this study. The muscle activity was recorded with surface electrodes over the erector spinae, multifidus, gluteus maximus (GM), and hamstring (Ham) muscles; it was measured by using surface EMG equipment under the following 3 experimental conditions: manual postural correction, verbal correction, and no correction. The maximal voluntary isometric contraction (MVIC) was determined for each muscle group in order to represent each exercise as a percentage of MVIC and allow for standardized comparison between subjects. A one-way analysis of variance was used to determine significant differences in the EMG activities of each muscle between the 3 experimental groups. During bridging exercises, the manual postural correction on normalized EMG activity of the GM muscle during manual guiding was significantly higher than during verbal guiding and without guiding (p<.05). Furthermore, the GM/Ham ratio was significantly higher during manual guiding than during verbal guiding and without guiding (p<.05). These findings suggest that the activities of the hip and trunk muscles may be favorably modified with manual guiding during bridging exercises.