Trunk muscle activity in healthy subjects during bridging stabilization exercises

Effects of Ankle Position While Performing One- and Two-Leg Floor Bridging Exercises on Core and Lower Extremity Muscle Recruitment

Given there are no known studies which have examined multiple lower extremity muscles between different ankle positions during bridging activities, the objective was to assess how employing two different ankle positions (PF versus DF) while performing five common bridging exercises (three bipedal and two unipedal) used in rehabilitation and athletic performance affect core and select lower extremity muscle EMG recruitment. Twenty healthy subjects performed a 5 s isometric hold during five two- and one-leg bridge exercises: (1) on right leg with left knee to chest (1LB-LFlex); (2) on right leg with left knee extended (1LB-LExt); (3) standard two-leg bridge (2LB); (4) two-leg bridge with resistance band around knees (2LB-ABD); and (5) two-leg bridge with ball between knees (2LB-ADD). Surface electromyographic (EMG) data were collected using a Noraxon Telemyo Direct Transmission System from fourteen muscles: (1) three superficial quadriceps (VM, VL, and RF); (2) three hip abductors (TFL, GMED, and GMAX); (3) medial hamstrings (ST) and lateral hamstrings (BF); (4) hip adductors (ADD); (5) erector spinae (ES); (6) latissimus dorsi (LATS); (7) upper rectus abdominis (RA); and (8) external oblique (EO) and internal oblique (IO). EMG data were normalized by maximum voluntary isometric contractions (MVICs). A paired t-test (p < 0.01) was used to assess differences in normalized mean EMG activities between DF and PF for each exercise. EMG activities were significantly greater in DF than PF for the (a) VM, VL, and RF during 1LB-LFlex; (b) ADD during 1LB-LFlex, 1LB-LExt; (c) EO during 1LB-LFlex; and (d) IO during 1LB-LFex. In contrast, EMG activities were significantly greater in PF than DF for ST and BF during all five bridge exercises. Bridging with PF (feet flat) was most effective in recruiting the hamstrings, while bridging with DF (feet up) was most effective in recruiting the quadriceps, hip adductors, and internal and external obliques.

MRI Compatible Lumbopelvic Movement Measurement System to Validate and Capture Task Performance During Neuroimaging

Research suggests that structural and functional changes within the brain are associated with chronic low back pain, and these cortical alterations might contribute to impaired sensorimotor control of the trunk and hips in this population. However, linking sensorimotor brain changes with altered movement of the trunk and hips during task-based neuroimaging presents significant challenges. An MRI-safe pressure measurement system was developed to ensure proper task completion during neuroimaging by capturing movement patterns of the trunk (sensors under the lower back) and hips (sensors embedded in the foam roll under the knees). Pressure changes were measured outside of the scanner by digital differential pressure sensors to capture time-series data and analog pressure gauges for real-time determination of task performance occurring within an MRI bore during brain imaging. This study examined the concurrent validity of air pressure changes between the digital and analog sensors. The digital and analog data were compared in 23 participants during the performance of modified bilateral and unilateral right and left hip bridges. Spearman's correlations were calculated for each sensor during the three bridging tasks and showed high positive correlations, indicating that over 87% of pressure change from the analog gauge can be explained by the pressure from the digital sensor. Bland-Altman plots showed no bias and mean differences were under three mmHg. This pressure system improves the rigor of future studies by validating the digital data from the system and increasing the capabilities of capturing lumbopelvic task performance occurring inside the scanner bore.

Trunk Muscle Activity and Ratio of Local Muscle to Global Muscle Activity during Supine Bridge Exercises under Unstable Conditions in Young Participants with and without Chronic Low Back Pain

Core exercises on an unstable surface increase trunk muscle activity, especially for local muscle groups. Therefore, there is a possibility that exercises on an unstable surface would be effective in the rehabilitation of non-specific chronic low back pain (NSCLBP). The present study assessed trunk muscle activities during bridge exercise on the floor and two kinds of unstable surfaces, i.e., a balance ball and the BOSU, for individuals with and without NSCLBP. This study enrolled 17 and 18 young participants with and without NSCLBP, respectively. In the balance ball condition, both groups showed a significant increase in erector spinae activity compared to the floor condition, and the increase in activity was significantly greater in the NSCLBP group than in the control group (p = 0.038). On the other hand, neither group showed significant changes in trunk muscle activities in the BOSU condition compared to those in the floor condition. The control group showed a significant increase in internal oblique/transversus abdominis activity under the balance ball condition (p = 0.020), whereas there were no significant changes in these muscle activities between the balance ball and floor conditions in the NSCLBP group. The present study showed that participants with NSCLBP significantly increased muscle activity of the erector spinae, one of the global back muscles, on the balance ball in spite of small effects on muscle activity of the internal oblique/transversus abdominis, which is one of the local abdominal muscles. Therefore, attention should be paid to the application of bridge exercises on the balance ball for individuals with NSCLBP.

Exercise Intensity Progressions and Criteria to Prescribe Core Stability Exercises in Young Physically Active Men: A Smartphone Accelerometer-Based Study

ABSTRACT

Heredia-Elvar, JR, Juan-Recio, C, Prat-Luri, A, Barbado, D, Ríos-Calonge, Jdl, and Vera-Garcia, FJ. Exercise intensity progressions and criteria to prescribe core stability exercises in young physically active men: a smartphone accelerometer-based study. J Strength Cond Res 38(2): 266-273, 2024-The establishment of core stability (CS) exercise intensity progressions in sport and clinical settings is normally based on subjective criteria. Therefore, this study aimed to develop exercise intensity progressions for some of the most common CS exercises through smartphone accelerometry and to analyze the effect of the subjects' lumbopelvic postural control on these progressions. Fifty-seven healthy young physically active male students performed 7 isometric variations of front bridge, back bridge, side bridge, and bird-dog exercises with a smartphone accelerometer placed on the pelvis. Mean pelvic accelerations were calculated during each variation to evaluate the lumbopelvic postural control challenge imposed on the subjects as an index of exercise intensity of difficulty. For the bridge exercises, long bridging produced higher pelvic accelerations than short bridging, bridging with single-leg support was more intense than bridging with double-leg support (even with both legs on a hemisphere ball for the back and front bridge), and the most difficult variations were those performed on a Swiss ball, mainly the variations with single-leg support. For the bird-dog exercise, the 2-point positions were more intense than the 3-point positions, the variations performed with a knee on the hemisphere ball produced higher pelvic accelerations than similar variations performed with the forearm on the hemisphere ball, and the variations with limb motions generated higher pelvic accelerations than similar variations performed without limb motions. Although the CS exercise progressions were very similar across subjects, our results showed the need to individualize the prescription of the CS exercise progressions based on the subjects' lumbopelvic postural control level.

Comparison of trunk muscle activity during lumbar stabilization exercises on stable and unstable surfaces

BACKGROUND

Lumbar stabilization exercises (LSE) provide dynamic trunk stability, promote muscle strength and endurance, and improve low back pain rehabilitation and performance.

OBJECTIVE

To clarify the differences in trunk muscle activity during LSEs on stable and different unstable surfaces.

METHODS

Fifteen healthy males performed three exercises (elbow-toe, hand-knee, and side bridge) on stable (floor) and unstable surfaces. Muscle activity of the bilateral rectus abdominis, internal oblique, external oblique, and erector spinae were recorded. Data were compared using the Friedman test. Pairwise comparisons were performed using Wilcoxon's signed rank test if significant differences were observed.

RESULTS

In the elbow-toe exercise, muscle activity of the rectus abdominis and right internal oblique increased in the following order: floor, low-difficulty, and high-difficulty unstable surface. In the hand-knee exercise, muscle activity of the internal oblique on the lower-extremity elevated side, external oblique, and erector spinae on the upper-extremity elevated side were greater on unstable surface exercise performance. In the side bridge exercise, rectus abdominis muscle activity was highest on a high-difficulty unstable surface.

CONCLUSION

Trunk muscle activity increased during exercise on unstable surfaces. Since the effects of unstable surfaces vary depending on muscle and exercise types, exercise difficulty and surface stability must be considered accordingly.

Ultrasound-guided muscle dissection for lumboperitoneal shunting via lateral abdominal laparotomy

Purpose;Lumboperitoneal shunting (LPS) is a common procedure for treating idiopathic normal pressure hydrocephalus (iNPH), involving two abdominal approaches:anterior abdominal laparotomy and lateral abdominal laparotomy (LAL). While LAL is advantageous in terms of infection risk, it presents challenges such as muscle manipulation and potential deviation from the desired trajectory. This report presents a novel technique that utilizes ultrasound examination of the lateral abdominal wall (UELAW) to visualize the three muscle layers (external oblique, internal oblique, and transversus abdominis) before abdominal manipulation during LAL. Illustrative Case;An 83-year-old iNPH patient underwent LPS with this approach, ensuring precise alignment of the trajectory and successful access to the abdominal cavity. Following the procedure, the patient experienced an improvement in gait disturbance and was discharged without any surgical complications. Conclusion;The use of UELAW during LPS provides clear visualization of the abdominal muscle layers, allowing surgeons to perform the procedure with confidence and accuracy, minimizing the risk of trajectory deviation, and ultimately improving patient outcomes. J. Med. Invest. 71 : 343-345, August, 2024.

Comparing the effectiveness of flexi-bar and stability exercises on postural control in chronic nonspecific low back pain: A randomized controlled study

Objectives

This study aimed to compare the effect of flexi-bar and stabilization exercises on static and dynamic postural control in patients with chronic nonspecific low back pain.

Patients and methods

In this randomized controlled study conducted between November 2019 and March 2020, 38 patients (19 males, 19 females; mean age: 33.8±6.2 years; range, 20 to 45 years) were randomly assigned into flexi-bar (n=19) and stabilization (n=19) groups. Both groups received general physiotherapy for three sessions per week, a total of 10 sessions. Besides, the flexi-bar group received flexi-bar exercises, and the stabilization group received stabilization exercises. Postural sway was assessed with a force platform in three difficult conditions, including open eye, close eye, and one-leg standing and dynamic posture with the modified Star Excursion Balance Test.

Results

After the intervention, both groups showed a significant improvement in static and dynamic postural control (p<0.05). However, no significant differences were found between groups after treatment, while only the phase-plane portrait of opened eyes condition was significantly improved (p=0.03), in the flexi-bar group compared to the stabilization group.

Conclusion

Both flexi-bar and stabilization exercises effectively improved static and dynamic postural control, but none of the exercises was superior to the other. Flexi-bar is recommended as an effective tool in low back pain rehabilitation.

Effect of Bridge Exercise Duration on Lateral Abdominal Muscle Thickness and Gluteus Maximus Activation

CONTEXT

Bridge exercises are extensively used in trunk-strengthening programs. The aim of this study was to investigate the effect of bridging duration on lateral abdominal muscle thickness and gluteus maximus activation.

DESIGN

Cross-sectional.

METHODS

Twenty-five young males participated in this study. Transversus abdominal (TrA), external and internal oblique ultrasound thickness, gluteus maximus electromyographic activation, and sacral tilt angle were simultaneously measured for every second during 30-second bridging exercise. The contraction thickness ratio and root mean squared signal (normalized to maximum isometric contraction signal) during 6 exercise durations (from 0 to 5, 10, 15, 20, 25, and 30 s) were also calculated and compared using analysis of variance designs.

RESULTS

TrA and internal oblique contraction thickness ratio and gluteus maximus root mean squared increased during the first 8 to 10 seconds and remained elevated until the end of the 30-second exercise (P < .05). External oblique contraction thickness ratio declined during exercise (P < .05). Five-second bridging showed less TrA thickness and anteroposterior and mediolateral sacral tilt angle and a lower anteroposterior tilt variability compared with bridges, which lasted more than 10 seconds (P < .05).

CONCLUSIONS

Bridge exercises longer than 10 seconds may be better for promoting TrA recruitment than bridges of shorter duration. Clinicians and exercise specialists could adjust the duration of bridge exercise based on the aims of the exercise program.

Does transversus abdominis function correlate with prone plank and bench bridge holding time in club cricket players?

Background

Bridge and plank holding times are used to evaluate core stability. Transversus abdominis (TA) muscle function is assessed using ultrasound and also provides input on an individual's core stability.

Objectives

A correlation study comparing TA muscle function with bridge and plank holding time in club cricketers.

Methods

Seventeen male, premier league cricketers (age: 22.1 ± 3.3 years) participated in this study. Ultrasound was used to measure bilateral TA, internal oblique (OI) and external oblique (OE) muscle thickness at rest and during abdominal hollowing. Muscle function was measured by means of a Pearson's correlation as the change in muscle thickness from rest to abdominal hollowing and compared to holding time of the bench bridge and prone plank (seconds).

Results

TA muscle thickness was preferentially recruited bilaterally (p=0.00001) during abdominal hollowing. No significant correlations were found between TA muscle function and holding time for the bench bridge (dominant (D): r = 0.03 [95% CI:-0.46-0.50]; non-dominant (ND): r = -0.02 [95% CI:-0.50-0.47]) or prone plank (D: r = -0.16 [95% CI:-0.60-0.34]; ND: r = -0.13 [95% CI:-0.57-0.38]).

Conclusion

Prone plank and bench bridge holding times are not correlated with TA muscle function during abdominal hollowing. Core stability cannot rely on a single test to evaluate its effectiveness. In particular, the contribution of the local and global muscle system to 'core stability' needs to be evaluated independently. Therefore these tests are not sensitive enough to evaluate the contribution of the local muscle system to the global muscle system in a healthy, pain free, sporting population.

An electromyographical comparison of torso muscle activity and ratio during modified side bridge exercises

BACKGROUND

Individualized exercise programs based on personal impairment could lead to successful rehabilitation. An effective way to train spine stability is to find exercises that take advantage of the synergistic relation between local and global stabilization systems.

OBJECTIVE

This study aimed to investigate synergistic relationship between the muscles of the local and global systems during three modified side bridge exercises compared with traditional side bridge (TSB).

METHODS

Twenty healthy participants performed TSB, both leg lift while side-lying (BLLS), torso lift on a 45∘ bench while side-lying (TLBS), and pelvic lift on side-lying (PLS) in random order. Surface electromyography data were analyzed.

RESULTS

The results indicate that PLS was effective as TSB on trunk muscle activity. However, BLLS and TLBS demonstrated significantly less rectus abdominal (RA) muscle activity compared to TSB (p< .001). Additionally, BLLS and TLBS had a higher internal oblique (IO)/RA muscle activity ratio than TSB (p< .001).

CONCLUSIONS

PLS could be a suitable alternative exercise for individuals who are unable to perform TSB, as it can effectively activate trunk muscles. BLLS and TLBS may be appropriate for training the local stability system, while limiting activation of the RA.

Immediate Effects of Stabilization Exercises on Trunk Muscle Activity during Jump Header Shooting: A Pilot Study

This study aimed to clarify trunk muscle activity during jump header shooting and examine the immediate effects of trunk stabilization exercises on trunk muscle activity. Nineteen males who had played soccer for over 5 years were assigned to either the trunk stabilization exercise group or the control group. Muscle activity during jump header shooting was measured before and after intervention. The intervention in the trunk stabilization exercise group was trunk muscle training, whereas that in the control group was sitting. The phases of jump header shooting and the effects of the interventions were compared. In pre-intervention measurements, the internal oblique activity during the push-off phase and early floating phase was significantly greater than that during the late floating phase (p < 0.01667). In pre-intervention measurements, the muscle activity of the internal oblique increased from the push-off phase, prior to the increase in muscle activity of the rectus abdominis and external oblique, whereas the muscle activity of all abdominal muscles increased immediately after take-off. The trunk stabilization exercise intervention decreased the muscle activity of the erector spinae (p < 0.05). There seems to be a certain activation sequence in the abdominals during jump header shooting, and a single application of stabilization exercises could possibly reduce the activation of the back muscles.

Immediate changes in chest mobility and trunk muscle activity during pelvic tilt following different trunk muscle exercises

BACKGROUND

Given the characteristics of the superficial trunk muscles that cross the chest and pelvis, their excessive contraction might limit chest mobility.

OBJECTIVE

To examine the immediate effects of two types of trunk muscle exercises on chest mobility and trunk muscle activities.

METHODS

Fourteen healthy men (age: 21.1 ± 1.0 years, height: 172.7 ± 5.6 cm, weight: 61.0 ± 7.1 kg, body mass index: 20.4 ± 1.7 kg/m2; mean ± SD) randomly performed trunk side flexion and draw-in exercises using a cross-over design. The chest kinematic data and trunk muscle activities were measured before and after each intervention during the following tasks: maximum inspiration/expiration and maximum pelvic anterior/posterior tilt while standing. Two-way repeated measures analysis of variance was used for statistical analysis (P< 0.05).

RESULTS

After the side flexion, upper and lower chest mobility significantly decreased, and superficial trunk muscle activity significantly increased during the maximum pelvic anterior tilt (P< 0.05). Additionally, after the draw-in, upper chest mobility significantly increased during the maximum pelvic anterior tilt (P< 0.05).

CONCLUSIONS

Increased activity of the superficial abdominal muscles might limit chest mobility during maximum pelvic anterior tilt. Conversely, the facilitation of deep trunk muscles might increase upper chest mobility during the maximum pelvic anterior tilt.

Effects of Knee Flexion Angles on the Joint Force and Muscle Force during Bridging Exercise: A Musculoskeletal Model Simulation

Bridging exercise is commonly used to increase the strength of the hip extensor and trunk muscles in physical therapy practice. However, the effect of lower limb positioning on the joint and muscle forces during the bridging exercise has not been analyzed. The purpose of this study was to use a musculoskeletal model simulation to examine joint and muscle forces during bridging at three different knee joint angle positions. Fifteen healthy young males (average age: 23.5 ± 2.2 years) participated in this study. Muscle and joint forces of the lumbar spine and hip joint during the bridging exercise were estimated at knee flexion angles of 60°, 90°, and 120° utilizing motion capture data. The lumbar joint force and erector spinae muscle force decreased significantly as the angle of the knee joint increased. The resultant joint forces were 200.0 ± 23.2% of body weight (%BW), 174.6 ± 18.6% BW, and 150.5 ± 15.8% BW at 60°, 90°, and 120° knee flexion angles, respectively. On the other hand, the hip joint force, muscle force of the gluteus maxims, and adductor magnus tended to increase as the angle of the knee joint increased. The resultant joint forces were 274.4 ± 63.7% BW, 303.9 ± 85.8% BW, and 341.1 ± 85.7% BW at a knee flexion angle of 60°, 90°, and 120°, respectively. The muscle force of the biceps femoris decreased significantly with increased knee flexion during the bridging exercise. In conclusion, the knee flexion position during bridging exercise has different effects on the joint and muscle forces around the hip joint and lumbar spine. These findings would help clinicians prescribe an effective bridging exercise that includes optimal lower limb positioning for patients who require training of back and hip extensor muscles.

The Relationship of Trunk Muscle Activation and Core Stability: A Biomechanical Analysis of Pilates-Based Stabilization Exercise

Pilates is an effective exercise method for rehabilitating musculoskeletal disorders as its principles are based on the activation of local muscles. This study aimed to compare the subjects with and without Pilates experience to find out the effect of the experience on the core muscle activity and muscle co-contraction, and to examine the relationship between the core muscle activation level and the kinematic data. This study involved 32 subjects, including 16 experienced Pilates practitioners and 16 non-experienced subjects. The knee stretch on the reformer was performed in three different positions: flat back with a neutral pelvis, round back with posteriorly tilted pelvis (RPP), and extended back anteriorly tilted pelvis (EAP). The electromyography of the internal oblique (IO), rectus abdominis (RA), multifidus (MU), and iliocostalis lumborum (IL) muscles were measured, as well as kinematic data from a 3D motion analysis system. Compared to the non-experienced subjects, the experienced subjects activated the IO muscles more than the RA muscles, and the most significant difference was seen in the RPP position (p < 0.05). The experienced patients activated the MU muscles more often than the IL muscles, with the most significant difference observed in the RPP position and the least significant in the EAP position (p < 0.05). All kinematic data and muscle activity (IO, IO/RA ratio, MU/IL ratio) showed significant differences between the experienced and non-experienced subjects (p < 0.05). The subjects presented a moderate correlation between muscle activation and core stability. It was confirmed that the experienced Pilates practitioners activated the abdominal and low back core muscles effectively, and the stability of the pelvis and trunk were better than that of the non-experienced participants. In addition, the better the trunk stability was maintained, the larger and more accurate movement of the mobility segment was observed.

Differences in myoelectric activity of the lumbar muscles between recurrent and chronic low back pain: a cross-sectional study

Background

Altered lower back muscle activity is proposed as a contributing factor to the reoccurrence and chronicity of low back pain (LBP). This study compared lumbar muscle activity during trunk extension in patients with continuous chronic LBP (CLBP), non-continuous CLBP, recurrent LBP (RLBP) and healthy subjects.

Methods

In 75 subjects (16 continuous CLBP, 15 non-continuous CLBP, 23 RLBP, 21 healthy controls), surface electromyographic (EMG) activity of the lumbar erector spinae (ES), multifidus (MF), latissimus dorsi (LD) and gluteus maximus (GM) was recorded during the concentric, holding and eccentric phase of a modified Biering Sorenson exercise.

Results

Continuous CLBP patients showed higher EMG activity in the ES and MF muscles compared to healthy controls in the concentric (p = 0.011; p = 0.009 respectively) and the holding phase (p = 0.015; p = 0.013). Higher EMG activity was observed in continuous CLBP compared to RLBP in the ES and MF muscles in the holding phase (p = 0.035; p = 0.037), and in the MF in the concentric phase (p = 0.046), but not in the ES (p = 0.062). No differences in muscle activity were established in either the concentric, holding, and eccentric phase for the LD and GM muscles. No differences were found between non-continuous CLBP and the other groups.

Conclusions

An enhanced muscle activity of the lumbar muscles during the concentric and holding phase was observed during trunk extension in patients with continuous CLBP compared to patients with RLBP and healthy subjects. No differences between groups are present in the GM and LD muscles during concentric and holding phases and for any muscle in the eccentric phase.

A self-oblique exercise that activates the coordinated activity of abdominal and hip muscles-A pilot study

The importance of an interaction between trunk stability muscles and hip muscle function has been suggested. However, reported exercises rarely act on the trunk and hip muscles simultaneously. Here, we devised an abdominal oblique and hip muscle exercise, the Self-oblique exercise (SOE). We examined whether SOE activated abdominal and hip muscles in the supine and half-kneeling positions, compared with abdominal crunch (AC) and plank exercises; and whether participants could modulate the exercise load. Participants were 20 healthy males with some sports experience such as football and baseball on average 10.5 ± 4.0 years. Participants applied self-pressure to their right thighs using the contralateral upper limb with 40% or 70% of the maximum force in Supine SOE and Half- kneeling SOE. The following abdominal and hip muscles were measured using surface electromyography: bilateral external obliques (EO), bilateral internal obliques (IO), right rectus abdominis, right gluteus medius (GMed), and right adductor longus (ADD). All evaluated muscle groups showed significant differences between exercises (p < 0.001). Supine SOE-70% showed 80.4% maximal voluntary contraction (MVC) for left EO (p < 0.017), 61.4% MVC for right IO (p < 0.027), 24.3% MVC for GMed (p < 0.002), and 42.4% MVC for ADD (p < 0.004); these were significantly greatest among all exercises. Muscle activity during Supine SOE-70% was greater than that during Supine SOE-40%. Similarly, Half-kneeling SOE-40% promoted abdominal and hip muscle exertion, and showed more significant activity in GMed (p < 0.006) and ADD (p < 0.001) than AC and plank. SOE could activate abdominal and hip muscles depends on the pressure applied by upper limb. Also, SOE allows participants to modulate the exercise load in a self-controlled step by step manner. Modulation of the exercise load is difficult in AC or plank compared to SOE, and AC or plank cannot obtain simultaneous oblique and hip muscle activity. SOE could be practiced anywhere, in various positions, without any tools.

The effects of pressure biofeedback on hip and trunk muscle activity and lumbopelvic alignment during one-leg standing

BACKGROUND: During one-leg standing (OLS), optimum activity of the gluteus medius (Gmed), multifidus (MF), and quadratus lumborum (QL) muscles relies upon maintaining neutral lumbopelvic alignment. However, no studies have examined how using pressure biofeedback during OLS affects the activity of these muscles and the concomitant alignment of the pelvis and trunk. OBJECTIVES: The purpose of this study was to investigate the effect of pressure biofeedback on the activity of the Gmed, MF, and QL and the femoropelvic and trunk lean angles during OLS. METHODS: Twenty-four healthy males performed OLS with (PB+) and without (PB-) pressure biofeedback. For all OLS conditions, a pressure sensor was placed between the lateral surface of the humerus on the non-supporting side and the wall. Under the PB- condition, participants performed preferred OLS while the examiner measured the maximum pressure caused by trunk lean. Under the PB+ condition, participants were asked to perform at a threshold of 50% of the maximal pressure (PB+ 1 condition) and with minimal change in pressure (PB+ 2 condition). Muscle activities of MF, QL, and Gmed as well as the femoropelvic and trunk lean angles were measured under various OLS conditions. RESULTS: The activity of the Gmed, MF, and QL was greater under both PB+ conditions than under the PB- condition (p< 0.05). Also, both PB+ conditions resulted in a greater femoropelvic angle and reduced trunk lean angle. There were no significant differences in muscle activity, femoropelvic angle, or trunk lean angle between PB+ 1 and PB+ 2 (p> 0.05). CONCLUSIONS: These results suggest that pressure biofeedback is a useful modality for increasing the activity of the Gmed and trunk muscles, especially the MF muscle on the non-supporting leg side, and for preventing compensatory movements such as trunk deviation and pelvic lateral deviation during OLS.

Hip and Core Muscle Activation During High-Load Core Stabilization Exercises

BACKGROUND

There is some evidence that high-load lumbar stabilization exercises, such as back bridge, can recruit both local and global muscles.

HYPOTHESIS

Therapeutic exercises would optimize gluteus maximus (GMax), gluteus medius (GMed), multifidus (MF), and transversus abdominis (TrA) activation, while minimizing the activation of the tensor fascia latae (TFL) and erector spinae (ES) muscles in healthy individuals.

DESIGN

Cross-sectional study.

SETTING

Research laboratory.

LEVEL OF EVIDENCE

Level 4.

METHODS

In this cross-sectional study, surface electromyography (EMG) of GMax, GMed, TFL, TrA, MF, and ES was used to quantify the gluteal-to-TFL muscle activation (GTA) index and a ratio of local to global (L/G) lumbar muscles during (1) the elbow-toe exercise in the prone position, (2) the elbow-toe with right left lifted, (3) the hand-knee with left arm and right leg lifted, (4) the back bridge, (5) the back bridge with right leg lifted, (6) the back bridge with left leg lifted, (7) the side bridge with left leg lifted, (8) the side bridge with right leg lifted, and (9) the elbow-toe with right leg horizontally lifted exercises in healthy individuals (20 men, 20 women; age, 25 ± 4 years).

RESULTS

The back bridge exercise with left leg lift generated the highest L/G muscles activity ratio (L/G = 3.35) while the hand-knee exercise yielded the lowest L/G muscles activity ratio (L/G = 1.21). The side bridge exercise with left elbow and foot and lifting the right leg (GTA = 63.78), hand-knee exercise (GTA = 49.62), back bridge (GTA = 28.05), and elbow-toe exercise with left leg horizontally lifted (GTA = 23.02) generated the highest GTA indices, respectively. Meanwhile, the normalized EMG amplitude for GMax was significantly less than the TFL, for elbow-toe exercise (P < 0.001), back bridge with left leg lift (P = 0.001), side bridge exercise with the right elbow and foot and lifting the left leg (P = 0.002), and elbow-toe exercise with right leg horizontally lifted (P < 0.001).

CONCLUSION

The highest GTA indexes were observed during (1) the side bridge lifting the dominant leg and (2) the hand-knee horizontally lifting dominant leg, respectively. The L/G ratio was highest during (1) the back bridge lifting nondominant leg, (2) back bridge, and (3) back bridge lifting dominant leg, respectively. This study supports the use of back bridge exercises to strengthen the MF and side bridges to improve gluteal muscle activation.

CLINICAL RELEVANCE

The highest GTA index was observed in the side bridge lifting the right leg. Highest L/G ratio was in the back bridge with nondominant leg lifted. This study supports the use of back bridge exercises to strengthen the MF. This study supports the use of side bridges to improve gluteal muscle activation.

Acute Responses of Core Muscle Activity during Bridge Exercises on the Floor vs. the Suspension System

This study aimed to compare the neuromuscular activation of selected core musculature in supine and prone bridge exercises under stable versus suspended conditions. Forty-three healthy male participants were recruited to measure the electromyographic activities of the rectus abdominis (RA), lumbar multifidus (LM), thoracic erector spinae (TES), rectus femoris (RF), gluteus maximus (GM), and biceps femoris (BF) during supine and prone bridge exercises under six conditions: control, both arms and feet on the floor (Prone_con and Supine_con); arms on the floor and feet on the suspension system (Prone-Feet_suspension and Supine-Feet_suspension); and arms on the suspension system and feet on the floor (Prone-Arm_suspension and Supine-Arm_suspension). Prone-Arm_suspension yielded significantly higher activities in the RA, RF, TES, and LM than Prone-Feet_suspension (p < 0.01) and Prone_con (p < 0.001). Moreover, Supine-Feet_suspension elicited significantly higher activities in the RA, RF, TES, LM, and BF than Supine-Arm_suspension (p < 0.01) and Supine_con (p < 0.001). Furthermore, Supine-Feet_suspension elicited significantly higher activities in the RF, TES, and BF than Supine_con (p < 0.01). Therefore, if the RA and/or RF were the target training muscles, then Prone-Arm_suspension was recommended. However, if the TES, LM, and/or BF were the target training muscles, then Supine-Feet_suspension was recommended.

Effects of Visual Biofeedback on Symmetrical Movements During Bridge Exercise With Sling

CONTEXT

Asymmetrical movements of trunk and lower-extremity are common during the bridge exercise on the unstable condition. However, no studies have investigated whether visual biofeedback of pressing pressure on the unstable surface changes muscle activation patterns of trunk and hip extensors and pelvic rotation during the bridge exercise.

OBJECTIVE

To investigate how visual biofeedback of pressing pressure influences symmetrical activity of lumbar and hip extensor and pelvic rotation.

DESIGN

Cross-sectional study.

SETTING

Laboratory.

PARTICIPANTS

Twenty healthy males participated in this study.

INTERVENTIONS

The participants performed 2 versions of the bridge exercise: the standard bridge exercise and the bridge exercise with visual biofeedback using amount of pressing pressure on the sling.

MAIN OUTCOME MEASURES

Surface electromyography was used to measure the symmetry (ie, the difference between dominant and nondominant sides) of muscle activation in the bilateral erector spinae, gluteus maximus, and hamstring muscles, and motion sensors were used to assess pelvic rotation. Symmetry of pressing pressure was measured using a tension meter.

RESULTS

The differences between the dominant and nondominant pressing pressures and differences between the electromyography activity of the dominant and nondominant erector spinae, gluteus maximus, and hamstring were significantly smaller during the bridge exercise with visual biofeedback than during the standard bridge exercise (P < .05). In addition, there was significantly less pelvic rotation during the bridge exercise with visual biofeedback than during the standard bridge exercise (P < .05).

CONCLUSIONS

The present findings suggest that visual biofeedback strategy may be a useful method for enhancing the symmetrical activation of the erector spinae, gluteus maximus, and hamstring and for reducing pelvic rotation during the bridge exercise on the unstable surface.

Lumbar Intervertebral Disc Degeneration Does Not Affect Muscle Synergy for Rowing Activities

Rowers with disc degeneration may have motor control dysfunction during rowing. This study is aimed at clarifying the trunk and lower extremity muscle synergy during rowing and at comparing the muscle synergy between elite rowers with and without lumbar intervertebral disc degeneration. Twelve elite collegiate rowers (with disc degeneration, n = 6; without disc degeneration, n = 6) were included in this study. Midline sagittal images obtained by lumbar T2-weighted magnetic resonance imaging were used to evaluate disc degeneration. Participants with one or more degenerated discs were classified into the disc degeneration group. A 2000 m race trial using a rowing ergometer was conducted. Surface electrodes were attached to the right rectus abdominis, external oblique, internal oblique, latissimus dorsi, multifidus, erector spinae, rectus femoris, and biceps femoris. The activity of the muscles was measured during one stroke immediately after 20% and 80% of the rowing trial. Nonnegative matrix factorization was used to extract the muscle synergies from the electromyographic data. To compare the muscle synergies, a scalar product (SP) evaluating synergy coincidence was calculated, and the muscle synergies were considered identical at SP > 75%. Both groups had only one module in the 20% and 80% time points of the trial. At the 20% time point of the 2000 m rowing trial, the SP of the module was 99.8%. At the 80% time point, the SP of the module was 99.9%. The SP results indicate that, at 20% and 80% time points, both groups had the same module. The module showed a high contribution in all muscles. The activation coefficients indicated that the module was always highly activated throughout the rowing stroke in both groups. The trunk and lower extremity muscles are mobilized through the rowing stroke and maintain coordination during rowing. There was no difference in the muscle synergy between the rowers with and without lumbar intervertebral disc degeneration.

Effects of upper-extremity movements on electromyographic activities of selected trunk muscles during leaning forward

BACKGROUND

Leaning forward has been accepted as a foundational approach to facilitate trunk-stabilizing muscles in the abdominal and lumbopelvic regions for patients with back pain during rehabilitation. However, how trunk muscles are activated and recruited during leaning forward performed under dynamic upper-extremity motion conditions is not completely understood.

OBJECTIVE

To determine whether activation of selected trunk muscles changes depending on shoulder movements during leaning forward exercise in healthy young adults.

METHODS

Twenty-four healthy adults (6 men and 18 women) participated in this study. The participants performed 3 types of leaning forward exercises: leaning forward alone (leaning forward 1), leaning forward with horizontal shoulder abduction (leaning forward 2), and leaning forward with shoulder flexion (leaning forward 3). Surface electromyography (EMG) was used to record activation of the erector spinae (ES), multifidus (MF), rectus abdominis (RA), and internal oblique (IO) on the dominant side.

RESULTS

There was a significant main effect of exercise type on the activation of the IO, RA, and MF muscles. Activation of the IO and MF during leaning forward 1 was significantly decreased compared to activation in leaning forward 2 and 3; the activation of IO and RA showed the greatest increase during leaning forward 3. Furthermore, the IO/RA ratio was significantly increased during leaning forward 2 and 3 in comparison to leaning forward 1; the MF/ES ratio was also significantly increased during leaning forward 3, compared with leaning forward 1.

CONCLUSION

The integration of shoulder movements during leaning forward exercises could be effective in the facilitation of EMG activity of IO and MF muscles, especially with shoulder flexion.

The effects of the three-dimensional active trunk training exercise on trunk control ability, trunk muscle strength, and balance ability in sub-acute stroke patients: A randomized controlled pilot study

BACKGROUND

Trunk control ability has been identified as an important early predictor of functional recovery after stroke.

OBJECTIVE

Our study aimed to investigate the effects of three-dimensional active trunk training exercise on trunk control ability, trunk muscle strength, and balance ability in sub-acute stroke patients.

METHODS

Twenty-four sub-acute stroke patients were randomly assigned to an experimental (n= 12) or control (n= 12) group. The experimental group (EG) performed three-dimensional active trunk training exercises using the Space Balance 3D system, while the control group (CG) performed only general trunk training exercises five times per week, for a total of three weeks. The Trunk Impairment Scale (TIS), trunk muscle strength, balance ability using the Space Balance 3D system, and Brunel Balance Assessment (BBA) scores were assessed before and after the intervention.

RESULTS

Pre-to-post intervention improvement was noted in all outcome measures for both groups (p< 0.05). Post intervention, the TIS, trunk muscle strength, static balance, and BBA scores were significantly higher in the EG than those in the CG (p< 0.05).

CONCLUSION

Our study suggests that the three-dimensional active trunk training exercise may be more effective compared to the general trunk training exercise in improving trunk control ability, trunk muscle strength, and balance ability in sub-acute stroke patients.

Change in Regional Activity of the Quadratus Lumborum During Bridge Exercises

CONTEXT

The quadratus lumborum (QL) is expected to contribute to segmental motor control of the lumbar spine to prevent low back pain. It has different layers (anterior [QL-a] and posterior [QL-p] layers), whose functional differences are becoming apparent. However, the difference between the QL-a and QL-p activities during bridge exercises utilized in rehabilitation is unclear.

OBJECTIVE

To compare QL-a and QL-p activities during bridge exercises.

DESIGN

Repeated-measurement design was used to assess electromyographic activity of trunk muscles recorded during 14 types of bridge exercises.

SETTING

University laboratory.

PARTICIPANTS

A total of 13 healthy men with no history of lumbar spine disorders participated.

INTERVENTION

The participants performed 14 types of bridge exercises (3, 3, and 8 types of side bridge, back bridge, and front bridge [FB], respectively).

MAIN OUTCOME MEASURES

Fine-wire electromyography was used for QL-a and QL-p activity measurements during bridge exercises.

RESULTS

Both QL-a and QL-p showed the highest activity during the side bridge with hip abduction  (47.3% [29.5%] and 43.0% [32.9%] maximal voluntary isometric contraction, respectively). The activity of the QL-a was significantly higher than that of the QL-p during back bridge with ipsilateral leg lift and FB elbow-toe with ipsilateral arm and contralateral leg lift (P < .05). With regard to the QL-p, the activity of the FB hand-knee with contralateral arm and ipsilateral leg lift, the FB elbow-knee with contralateral arm and ipsilateral leg lift, and the FB elbow-toe with contralateral arm and ipsilateral leg lift were significantly higher than that of the FB elbow-knee and FB elbow-toe (P < .05).

CONCLUSION

This study indicates different regional activities; the QL-a activated during the back bridge with ipsilateral leg lift and FB with ipsilateral arm lift, and the QL-p activated during the FB with ipsilateral leg lift. These results have implications for the rehabilitation of low back pain or lumbar scoliosis patients based on QL recruitment.

Abdominal muscle activation: An EMG study of the Sahrmann five-level core stability test

Background

Sahrmann five-level core stability test protocol has been used to evaluate the ability of the core muscles to stabilize the spine. However, validation studies on the Sahrmann protocol are limited.

Objective

The purpose of this study was to compare the different levels of Sahrmann five-level core stability (levels 1-5) on the muscle activity of rectus abdominis (RA), external oblique (EO), and transverse abdominis/internal oblique (TrA/IO).

Methods

Twenty-two asymptomatic male participants aged 21.3 6 ± 1 .59 years were recruited. Participants were instructed to perform maximum voluntary contraction (MVC) and five levels of Sahrmann five-level core stability test guided with a pressure biofeedback unit (PBU). The surface electromyography (EMG) data of each muscle during five levels of Sahrmann five-level core stability test were normalized as a percentage of MVC.

Results

Results showed significant differences in the normalized EMGs of RA [ χ 2 (4) = 64.80, p < 0 .001], EO [ χ 2 (4) = 58.11, p < 0 .001], and TrA/IO [ χ 2 (4) = 56.00, p < 0 .001] between the five levels of Sahrmann five-level core stability test. Post-hoc analysis revealed Sahrmann levels 5 and 3 have significantly higher abdominal EMG signals than levels 4, 2, and 1 ( p < 0 .001).

Conclusion

In conclusion, the Sahrmann five-level core stability test differs according to the level of Sahrmann tests. Significantly higher abdominal muscle activities were observed during levels 3 and 5. Therefore, the classification exchange in levels 3 and 4 of the Sahrmann five-level core stability test should be reconsidered in the future.

The Effect of Additional External Resistance on Inter-Set Changes in Abdominal Muscle Thickness during Bridging Exercise

Bridging exercises with abdominal hollowing are often used as a regimen for improving spinal stability. Lately, this type of training has become very popular among elite athletes, creating a need for more demanding exercises. The purpose of this study was to investigate whether the use of additional external resistance is beneficial for abdominal muscle recruitment during bridge exercise. Tissue movement of the transversus abdominis (TrA) and the rectus abdominis (RA) was recorded with the use of two synchronized ultrasonic devices, in 20 healthy college students. From the hook-lying position participants were examined in eight different exercise conditions: a) rest, b) abdominal drawing-in maneuver (ADIM), c) bridge, d) bridge- ADIM, e) bridge with 10KG, f) bridge- ADIM with 10KG, g) bridge with 20KG and h) bridge-ADIM with 20KG. Analysis of variance (ANOVA) showed a statistically significant increase in TrA thickness when performing the bridge exercise combined with ADIM compared to rest mode (p < .05). RA thickness decreased when the ADIM was performed, compared to rest (p < 0.05). No significant difference in TrA and RA thickness when exercising with and without external resistance was observed (p > 0.05). The main outcome of this study was that external loading provided some extra level of difficulty, yet it was not beneficial for abdominal muscle recruitment, when performing a supine bridge exercise.

Progressions of core stabilization exercises based on postural control challenge assessment

PURPOSE

The intensity progression of core stabilization exercises (CSEs) is usually based on personal criteria rather than on objective parameters. To develop exercise progressions for four of the most common CSEs based on the postural control challenge imposed on the participants, and to analyze the effect of participants' sex and postural control level on these progressions.

METHODS

Seventy-six males and females performed five variations of front bridge, back bridge, side bridge and bird-dog exercises on two force platforms. The mean velocity of the center of pressure displacement was calculated to assess exercise intensity through the measurement of the participants' body sway (PBS).

RESULTS

In general, long bridges produced higher PBS than short bridges, bridging with single leg support produced higher PBS than bridging with double leg support and bridging on a hemisphere ball produced higher PBS than bridging on the floor. The most difficult bridging variations were those performed on a hemisphere ball with single leg support. Regarding the bird-dog, two-point positions produced higher PBS than three-point positions and the positions performed on a hemisphere ball produced higher PBS than those performed on the floor.

CONCLUSION

The CSE progressions obtained by males and females were very similar. However, the participants with high trunk control showed less significant differences between exercise variations than the participants with low trunk control, which shows the need to individualize the progressions according to the participants' training level. Overall, this study provides useful information to guide the prescription of CSE progressions in young physically active individuals.

Trunk muscle activity during trunk stabilizing exercise with isometric hip rotation using electromyography and ultrasound

INTRODUCTION

The purpose of this study was to clarify the muscle activation during trunk stabilizing exercise with isometric hip rotation in healthy males by comparing that with abdominal crunch (AC) and active straight leg raise (ASLR). Electromyography and ultrasound imaging were used to simultaneously measure muscle activity and thickness of the internal oblique (IO), the external oblique (EO), transverse abdominis (TrA) and multifidus (MF) on the right side during exercise.

METHODS

Twenty healthy participants performed the following exercises in supine position: isometric right or left hip internal/external rotation, AC, and ASLR. Muscle activity was normalized to maximum voluntary contraction (MVC), and muscle thickness was normalized to resting muscle thickness.

RESULTS

Muscle activation and thickness of IO, MF and TrA increased significantly during the isometric hip rotation compared with other exercises. Muscle activation during the trunk stabilizing exercise with ipsilateral isometric hip internal rotation was 21% in IO, 26% in MF, and with ipsilateral hip external rotation was 12% of MVC in EO.

CONCLUSION

These findings suggest that trunk stabilizing exercise with isometric hip rotation exercise may be a more safe and effective exercise to promote trunk muscle activity than AC and ASLR. These findings would be beneficial for therapists engaged in prevention and treatment of low back pain.

The effect of the trunk and gluteus maximus muscle activities according to support surface and hip joint rotation during bridge exercise

[Purpose] The purposes of this study were to strengthen gluteus maximus and trunk muscles depending upon the hip joint direction by bridging exercise on an unstable and stable surface, and to suggest an intervention method for efficient and selective exercise. [Participants and Methods] The test measured the muscle activities with the external rotation and internal rotation of 25 degrees and hip joint neutral position of 0 degree on a stable and unstable surface each exercise 3 times for 9 seconds. [Results] External oblique abdominis showed a higher muscle activity on the unstable surface and internal rotation. Erector spinae showed no significant difference on the surfaces and demonstrated the highest muscle activity at the internal rotation. Gluteus maximus showed a higher muscle activity on the stable surface and external rotation and the interaction effect between the surface and the angle indicated a statistical significance as well. [Conclusion] Muscle activities appear different depending upon the change of surface and joint angle, and it can be said that the correct mobilization of muscle fiber relying on the muscle arrangement direction and muscle contraction direction is the most important factor for gluteus maximus.

Effects of pulse ultrasound and kneading massage in managing individual with incessant pain at lower region of back using random allocation

The study examined the effect of pulsed therapeutic ultrasound in management of patients with incessant pain at lower region of the back (PWIPLB) in comparison with kneading massage (KM). Fifty PWIPLB recruited purposively were randomly assigned into ultrasound group (USG) and KM group (KMG) equally. Subjects received back extension exercises as baseline treatment. USG received pulse ultrasound (PUS) while KMG was treated using KM. The treatments were administered 2 times weekly for a 6-week period. Severity of pain (SP) and inability of patient (IoP) were evaluated at baseline, 3rd week and 6th week of treatment. Values of the variables obtained were classified and the implications were summarised. A significant change was observed in precompared with posttreatment SP (F=32.6, P=0.000) and IoP (F=2.5, P<0.021) in USG. A significant change was observed in precompared with posttreatment IoP (F=4.1, P<0.05) but not in SP (F=2.9, P<0.086). In the 6th week, there was a significant reduction of SP in the USG relative to SP in the KMG (F=11.98, P=0.000), and there was improvement significantly in the IoP in the KMG relative to that in the USG (F=2.58, P=0.05). PUS may be better than KM in management of SP but KM is better than PUS in IoP with PWCPLB.

Do Verbal and Tactile Cueing Selectively Alter Gluteus Maximus and Hamstring Recruitment During a Supine Bridging Exercise in Active Females? A Randomized Controlled Trial

Context: Hip extension with hamstring-dominant rather than gluteus maximus-dominant recruitment may increase anterior femoracetabular forces and contribute to conditions that cause hip pain. Cueing methods during hip extension exercises may facilitate greater gluteus maximus recruitment. Objective: We examined whether specific verbal and tactile cues facilitate gluteus maximus recruitment while inhibiting hamstring recruitment during a bridging exercise. Design: Randomized controlled trial. Setting: Biomechanics laboratory. Participants: 30 young adult women (age 24 [3] y; BMI 22.2 [2.4] kg/m2). Intervention: Participants were tested over 2 sessions, 1 week apart, while performing 5 repetitions of a bridging exercise. At their second visit, participants in the experimental group received verbal and tactile cues intended to facilitate gluteus maximus recruitment and inhibit hamstring recruitment. Control group participants received no additional cues beyond original instructions. Main Outcome Measures: Gluteus maximus and hamstring recruitment were measured with surface electromyography, normalized to maximal voluntary isometric contractions (MVICs). Results: Gluteus maximus recruitment was unchanged in the control group and increased from 16.8 to 33.0% MVIC in the cueing group (F = 33.369, P < .001). Hamstring recruitment was unchanged in the control group but also increased from 16.5 to 29.8% MVIC in the cueing group (F = 6.400, P = .02). The effect size of the change in gluteus maximus recruitment in the cueing group (Cohen’s d = 1.5, 95% CI = 0.9 to 2.2) was not significantly greater than the effect size in hamstring recruitment (Cohen’s d = 0.8, 95% CI = 0.1 to 1.5). Conclusions: Verbal and tactile cues hypothesized to facilitate gluteus maximus recruitment yielded comparable increases in both gluteus maximus and hamstring recruitment. If one intends to promote hip extension by facilitating gluteus maximus recruitment while inhibiting hamstring recruitment during bridging exercises, the cueing methods employed in this study may not produce desired effects.

Effect of modified bridge exercise on trunk muscle activity in healthy adults: a cross sectional study

•

Bridge exercise with unstable surface increases trunk muscle activities.

•

Bridge exercise with hip abduction increases trunk muscles activities.

•

Modified bridge exercises are useful for co-activation of trunk muscles.

Design

This is a cross-sectional study.

Setting

University research laboratory.

Participants

Fifteen healthy adults (mean age: 27.47 years) volunteered for this study.

Intervention

The individuals performed standard bridge exercise and modified bridge exercises with right leg-lift (single-leg-lift bridge exercise, single-leg-lift bridge exercise on an unstable surface, and single-leg-lift hip abduction bridge exercise).

Main outcome measures

During the bridge exercises, electromyography of the rectus abdominis, internal oblique, erector spinae, and multifidus muscles was recorded using a wireless surface electromyography system. Two-way repeated-measures analysis of variance (exercise by side) with post hoc pairwise comparisons using Bonferroni correction was used to compare the electromyography data collected from each muscle.

Results

Bilateral internal oblique muscle activities showed significantly greater during single-leg-lift bridge exercise (95% confidence interval: right internal oblique = −8.99 to −1.08, left internal oblique = −6.84 to −0.10), single-leg-lift bridge exercise on an unstable surface (95% confidence interval: right internal oblique = −7.32 to −1.78, left internal oblique = −5.34 to −0.99), and single-leg-lift hip abduction bridge exercise (95% confidence interval: right internal oblique = −17.13 to −0.89, left internal oblique = −8.56 to −0.60) compared with standard bridge exercise. Bilateral rectus abdominis showed greater electromyography activity during single-leg-lift bridge exercise on an unstable surface (95% confidence interval: right rectus abdominis = −9.33 to −1.13, left rectus abdominis = −4.80 to −0.64) and single-leg-lift hip abduction bridge exercise (95% confidence interval: right rectus abdominis = −14.12 to −1.84, left rectus abdominis = −6.68 to −0.16) compared with standard bridge exercise. In addition, the right rectus abdominis muscle activity was greater during single-leg-lift hip abduction bridge exercise compared with single-leg-lift bridge exercise on an unstable surface (95% confidence interval = −7.51 to −0.89). For erector spinae, muscle activity was greater in right side compared with left side during all exercises (95% confidence interval: standard bridge exercise = 0.19–4.53, single-leg-lift bridge exercise = 0.24–10.49, single-leg-lift bridge exercise on an unstable surface = 0.74–8.55, single-leg-lift hip abduction bridge exercise = 0.47–11.43). There was no significant interaction and main effect for multifidus.

Conclusions

Adding hip abduction and unstable conditions to bridge exercises may be useful strategy to facilitate the co-activation of trunk muscles.

Wearing an Inflatable Vest Alters Muscle Activation and Trunk Angle While Paddling a Surfboard

Low back pain is a commonly reported problem among recreational surfers. Some individuals report that wearing a vest with an inflatable bladder that alters trunk angle may help to alleviate pain. The purpose of this study was to determine whether such a vest has an effect on muscle activation and extension of the lower back. Twelve recreational surfers completed 12 paddling trials at 1.1 m/s in a swim flume on both a shortboard and a longboard on 2 separate days. Three conditions of no vest, vest uninflated, and vest inflated were presented to participants in random order. Surface EMG and trunk angle were acquired via wireless sensors placed over the right erector spinae, mid-trapezius, upper trapezius, and latissimus dorsi. Wearing the inflated vest affected muscle activation: erector spinae and mid-trapezius demonstrated a significant decrease in activation relative to wearing no vest (12% and 18% respectively, p < .05). Trunk extension was also significantly reduced when the vest was inflated (18% reduction, p < .05). Results were similar for both the short and longboard, though this effect was greater while paddling the larger board. These results suggest that a properly inflated vest can alter trunk extension and muscle activity while paddling a surfboard in water.

Reliability and Practicality of the Core Score: Four Dynamic Core Stability Tests Performed in a Physician Office Setting

OBJECTIVE

Pilot study to determine the practicality and inter-rater reliability of the "Core Score," a composite measure of 4 clinical core stability tests.

DESIGN

Repeated measures.

SETTING

Academic hospital physician clinic.

PARTICIPANTS

23 healthy volunteers with mean age of 32 years (12 females, 11 males).

ASSESSMENT OF VARIABLES

All subjects performed 4 core stability maneuvers under direct observation from 3 independent physicians in sequence.

MAIN OUTCOME MEASURES

Inter-rater reliability and time necessary to perform examination.

RESULTS

The Core Score scale is 0 to 12, with 12 reflecting the best core stability. The mean composite score of all 4 tests for all subjects was 9.54 (SD, 1.897; range, 4-12). The intraclass correlation coefficients (ICC 1,1) for inter-rater reliability for the composite Core Score and 4 individual tests were 0.68 (Core Score), 0.14 (single-leg squat), 0.40 (supine bridge), 0.69 (side bridge), and 0.46 (prone bridge). The time required for a single examiner to assess a given subject's core stability in all 4 maneuvers averaged 4 minutes (range, 2-6 minutes).

CONCLUSIONS

Even without specialized equipment, a clinically practical and moderately reliable measure of core stability may be possible. Further research is necessary to optimize this measure for clinical application.

CLINICAL RELEVANCE

Despite the known value of core stability to athletes and patients with low back pain, there is currently no reliable and practical means for rating core stability in a typical office-based practice. This pilot study provides a starting point for future reliability research on clinical core stability assessments.

Responsiveness of the bridge maneuvers in subjects with symptomatic lumbar spondylolisthesis: A prospective cohort study

BACKGROUND AND PURPOSE

To date no study was made on the responsiveness of Bridge tests (BTs) in subjects with low back pain and spondylolisthesis (SPL) submitted to a physical therapy program. The objective of this study is to examine the responsiveness of the BTs in subjects with symptomatic lumbar SPL.

METHODS

One hundred twenty patients with symptomatic SPL received physical therapy treatments for a number of sessions depending on the individual patient's needs. Each session included supervised exercises and the teaching of home exercises aiming to improve the lumbar stability, for about 1 hr in total. At the beginning and immediately after the last session of treatment, participants completed the Oswestry Disability Index - Italian version and the Pain Numerical Rating Scale, and performed the supine bridging (SBT) and the prone bridging (PBT). The global perception of effectiveness was measured with a seven-point Likert scale Global Perceived Effect questionnaire.

RESULTS

The mean post-treatment change score (95% confidence interval [CI]) was 18.2 s (14.5; 21.9) for the PBT and 43.9 s (35.1; 52.8) for the SBT, all p < .001. The area under the receiver operating characteristic curve for the PBT was 0.83 (95% CI 0.74-0.91) and for the SBT was 0.703 (95% CI 0.61-0.80). The optimal cutoff points were 19.5 s for the PBT and 62.5 s for the SBT. Logistic regression revealed that PBT (odds ratio = 0.952) was associated with the type of SPL. The final regression model explained 36.4% (R²  = 0.36; p = .001) of the variability.

DISCUSSION

Bridge maneuvers proved to be responsive, because their results were significantly related to pain and disability changes. BTs may be suggested to detect clinical changes after physical therapy treatment in symptomatic SPL. Copyright © 2017 John Wiley & Sons, Ltd.

Anatomical Correlation of Core Muscle Activation in Different Yogic Postures

Faulty postures due to sedentary lifestyle cause weakening of core muscles which contributes to increased incidence of musculoskeletal disorders (MSDs). Although a few research studies have quantified the core muscle activity in various yogic exercises used in rehabilitation programs, evidence correlating it to functional anatomy is scarce. Such information is important for exercise prescription when formulating treatment plans for MSDs. Therefore, the objective of this review article is to examine the literature and analyze the muscle activity produced across various yoga postures to determine which type of yoga posture elicits the highest activation for the core muscle in individuals. Literature search was performed using the following electronic databases: Cochrane Library, NCBI, PubMed, Google Scholar, EMBASE, and web of science. The search terms contained: Core muscle activation and yogic posture OR yoga and rehabilitation OR intervention AND Electromyography. Activation of specific core muscle involved asanas which depended on trunk and pelvic movements. Description of specific yogic exercise as they relate to core muscles activation is described. This information should help in planning yogic exercises that challenge the muscle groups without causing loads that may be detrimental to recovery and pain-free movement. Knowledge of activation of muscles in various yogic postures can assist health-care practitioners to make appropriate decisions for the designing of safe and effective evidence-based yoga intervention for MSDs.

Effects of 3-Dimensional Lumbar Stabilization Training for Balance in Chronic Hemiplegic Stroke Patients: A Randomized Controlled Trial

Objective

To investigate the effects of the newly developed Spine Balance 3D system on the balance and gait abilities of hemiplegic stroke patients.

Methods

Twenty-eight hemiplegic patients with chronic stroke were randomly assigned to an experimental (n=14) or control group (n=14). The experimental and control groups performed balance training by using the newly developed Spine Balance 3D system and the well-known Biodex Balance System 30 minutes per day, three times a week for 7 weeks. The Berg Balance Scale (BBS), 10-m walking test (10mWT), Timed Up and Go Test (TUG), Functional Reach Test (FRT), the Korean version of the Fall Efficacy Scale-International (KFES-I), trunk muscle strength and stability were evaluated before and after 7 weeks of intervention.

Results

The 10mWT improved significantly (p=0.001) in the experimental group (using the Spine Balance 3D system) but not in the control group, and core muscle strength, which we checked using Spine Balance 3D system evaluation program, improved more in the experimental group as well. The results of the BBS, FRT, TUG, KFES-I, and Biodex Balance System evaluation program improved in both groups after 7 weeks of balance training.

Conclusion

We suggest that the newly-developed Spine Balance 3D system can be a more useful therapeutic tool for gait and dynamic balance rehabilitation in hemiplegic patients than a conventional 2D-based balance training system. A large-scale randomized controlled study is needed to prove the effect of this system.

The effects of forced breathing exercise on the lumbar stabilization in chronic low back pain patients

[Purpose] This study was conducted to investigate the effects of forced breathing exercise on the trunk functions of chronic low back pain patients. [Subjects and Methods] Twenty-four patients with chronic low back pain were randomly divided into groups of respiratory effort and trunk stabilization exercises. The exercises were performed for 45 minutes, 3 times per week for 6 weeks. Spinal stabilization was measured as the compensation of thesagittal angle joint in relation to the lumbar external load. [Results] After the intervention, the forced breathing and stabilization exercise groups showed a significant difference in lumbar spine stabilization between the first and second stress tests and the control group also showed a significant difference after the intervention. The M1 and M2 tests of lumbar spine stabilization revealed no significant differences between the groups. [Conclusion] The results of this research demonstrate that forced breathing exercise therapy is effective at improving the trunk stability and daily living activities of chronic low back pain patients.

Pelvic floor muscle contraction and abdominal hollowing during walking can selectively activate local trunk stabilizing muscles

BACKGROUND

Trunk muscle exercises are widely performed, and many studies have been performed to examine their effects on low back pains. However, the effect of trunk muscles activations during walking with pelvic floor muscle contraction (PFMC) and abdominal hollowing (AH) has not been clarified.

OBJECT

To investigate whether walking with PFMC and AH is more effective for promoting local trunk muscle activation than walking without PFMC and AH.

METHODS

Twenty healthy men (28.9 ± 3.14 years, 177.2 ± 4.25 cm, 72.1 ± 6.39 kg, body mass index 22.78 ± 2.38 kg/m2) were participated in this study. Surface electrodes were attached over the multifidus (MF), lumbar erector spinae (LES), thoracic erector spinae (TES), transverse abdominus-internal oblique abdominals (TrA-IO), external oblique abdominals (EO), and rectus abdominus (RA). The amplitudes of electromyographic signals were measured during a normal walking with and without PFMC and AH.

RESULT

PFMC and AH while walking was found to result in significant bilateral increases in the normalized maximum voluntary contraction (MVC) of MFs and TrA-IOs (p< 0.05). Ratios of local muscle activity to global muscle activities were increased while performing PFMC and AH during normal walking. Bilateral TrA-IO/EO activity ratios were significantly increased by PFMC and AH (p< 0.05).

CONCLUSION

Performance of the PFMC and AH during walking resulted in significantly more recruitment of local trunk muscles. This study suggests that PFMC and AH during normal daily walking improves activation of muscles responsible for spinal dynamic stabilization and might be useful if integrated into low back disability and pain physical rehabilitation efforts.

The effect of resistance exercise direction for hip joint stabilization on lateral abdominal muscle thickness

The aim of this study was to determine the effects of resistance direction in hip joint stabilization exercise on change in lateral abdominal muscle thickness in healthy adults. Twenty-six healthy adults were randomly allocated to either a hip stabilization exercise by hip straight resistance group (n=12) or a hip diagonal resistance group (n=14). The outcome measures included contraction thickness ratio in transversus abdominis (TrA), internal oblique (IO) and external oblique, and TrA lateral slide were assessed during the abdominal drawing-in maneuver by b-mode ultrasound. The researcher measured the abdominal muscle thickness of each participant before the therapist began the intervention and at the moment intervention was applied. There was a significant difference in lateral abdominal muscle thickness between the straight resistance exercise of hip joint group and the diagonal resistance exercise of hip joint group. Significant differences were found between the two groups in the percentage of change of muscle thickness of the TrA (P=0.018) and in the thickness ratio of the TrA (P=0.018). Stability exercise accompanied by diagonal resistance on the hip joint that was applied in this study can induce automatic contraction of the IO and TrA, which provides stability to the lumbar spine.

Magnitude of muscle activity of the lumbar multifidus using the Core-Noodle device with varied upper extremity postures

BACKGROUND

Lumbar Multifidus (LM) exercise is a treatment in patients with low back pain. We designed a new exercise using device ``Core-Noodle'' (Copyright has been observed in Japan).

OBJECTIVE

The purpose of this study was to record the electromyographic (EMG) activity of the lumbar multifidus during a novel exercise.

METHODS

Twenty-one healthy young volunteers performed the LM exercise using Core-Noodle in three conditions: no-weight (NW), 1 kg weight (1W), 2 kg-weight (2W). This exercise was performed in supine with left shoulder abduct 90 degrees and right shoulder flexed 90 degrees. EMG activity was recorded from surface electrodes on the LM and the thoracic part of the iliocostalis lumborum (ICLT), and normalized to values derived from maximal isometric trials (%MVIC). In addition, the ratio of the LM to ICLT (L/G ratio) was calculated to compare selectivity of LM activity. One-way ANOVA and Bonferroni method were used to draw comparisons among the three conditions.

RESULTS

Muscle activation of LM was gradually increased in proportion to the loading dose. L/G ratio increased by weight loading significantly, but slightly decreased at 2W.

CONCLUSIONS

The results suggest that characteristic EMG patterns of LM ``selective contraction'' and ``adjustment of load'' are obtained concurrently.

Effects of a 16-week Pilates exercises training program for isometric trunk extension and flexion strength

OBJECTIVE

To evaluate the effects of Pilates exercises designed to improve isometric trunk extension and flexion strength of muscles in women with chronic low back pain (cLBP).

PARTICIPANTS

Female volunteers with cLBP were divided into an experimental group (EG; n = 27) and a control group (CG; n = 27).

INTERVENTION

Pilates exercises were performed twice per week by the EG; the duration of each session was 60 min. The program lasted for 16 weeks; thus patients underwent a total of 32 exercise sessions.

RESULTS

The maximum isometric waist bending strength of the EG had improved significantly (p = 0.001) after 16 weeks of the Pilates program. The results of trunk flexion muscle endurance tests significantly depended on the trunk extension muscle endurance before the intervention, and at 1 month (r = 0.723, p < 0.001) and 2 months (r = 0.779, p < 0.001) after the Pilates exercise program. At the end of the 16-week exercise program, cLBP intensity decreased by 2.01 ± 0.8 (p < 0.05) in the EG, and this reduction persisted for 1 month after completion of the program.

CONCLUSIONS

At 1 and 2 months after cessation of the Pilates exercise program the pain intensified and the functional state deteriorated much faster than the maximum trunk muscle strength. Therefore, it can be concluded that, to decrease pain and improve functional condition, regular exercise (and not only improved strength and endurance) is required. We established that, although the 16-week lumbar stabilization exercise program increased isometric trunk extension and flexion strength and this increase in strength persisted for 2 months, decreased LBP and improved functional condition endured for only 1 month.

Comparison of EMG activity on abdominal muscles during plank exercise with unilateral and bilateral additional isometric hip adduction

The aim of this study was to investigate the effects of additional isometric hip adduction during the plank exercise on the abdominal muscles. Twenty healthy young men participated in this study. Surface electromyography (EMG) was used to monitor the activity of the bilateral rectus abdominis (RA), the internal oblique (IO), and the external oblique (EO) muscles. The participants performed three types of plank exercise; the standard plank exercise, the plank exercise with bilateral isometric hip adduction, and the plank exercise with unilateral isometric hip adduction. All abdominal muscle activity was significantly increased during the plank exercise combined with the bilateral and unilateral isometric hip adduction compared with the standard plank exercise (p<0.05). Bilateral IO, EO, and left RA muscle activity was significantly increased during the unilateral isometric hip adduction compared with the bilateral isometric hip adduction (p<0.05). These findings suggest that additional isometric hip adduction during the plank exercise could be a useful method to enhance abdominal muscle activity. In particular, the unilateral isometric hip adduction is a more beneficial exercise than the bilateral isometric hip adduction.

The comparison of abdominal muscle activation on unstable surface according to the different trunk stability exercises

[Purpose] This study aimed to determine the effect of abdominal muscle activities and the activation ratio related to trunk stabilization to compare the effects between the abdominal drawing-in maneuver and lumbar stabilization exercises on an unstable base of support. [Subjects and Methods] Study subjects were 20 male and 10 female adults in their 20s without lumbar pain, who were equally and randomly assigned to either the abdominal drawing-in maneuver group and the lumbar stabilization exercise group. Abdominal muscle activation and ratio was measured using a wireless TeleMyo DTS during right leg raise exercises while sitting on a Swiss ball. [Results] Differences in rectus abdominis, external oblique abdominis, and internal oblique abdominis muscle activation were observed before and after treatment. Significant differences were observed between the groups in the muscle activation of the external oblique abdominis and internal oblique abdominis, and the muscle activation ratio of external oblique abdominis/rectus abdominis and internal oblique abdominis/rectus abdominis. [Conclusion] Consequently trunk stability exercise enhances internal oblique abdominis activity and increases trunk stabilization. In addition, the abdominal drawing-in maneuver facilitates the deep muscle more than LSE in abdominal muscle. Therefore, abdominal drawing-in maneuver is more effective than lumbar stabilization exercises in facilitating trunk stabilization.

The Activity of Surface Electromyographic Signal of Selected Muscles during Classic Rehabilitation Exercise

Objectives. Prone bridge, unilateral bridge, supine bridge, and bird-dog are classic rehabilitation exercises, which have been advocated as effective ways to improve core stability among healthy individuals and patients with low back pain. The aim of this study was to investigate the activity of seven selected muscles during rehabilitation exercises through the signal of surface electromyographic. Approaches. We measured the surface electromyographic signals of four lower limb muscles, two abdominal muscles, and one back muscle during rehabilitation exercises of 30 healthy students and then analyzed its activity level using the median frequency method. Results. Different levels of muscle activity during the four rehabilitation exercises were observed. The prone bridge and unilateral bridge caused the greatest muscle fatigue; however, the supine bridge generated the lowest muscle activity. There was no significant difference (P > 0.05) between left and right body side muscles in the median frequency slope during the four rehabilitation exercises of seven muscles. Conclusions. The prone bridge can affect the low back and lower limb muscles of most people. The unilateral bridge was found to stimulate muscles much more active than the supine bridge. The bird-dog does not cause much fatigue to muscles but can make most selected muscles active.

Effects of trajectory exercise using a laser pointer on electromyographic activities of the gluteus maximus and erector spinae during bridging exercises

[Purpose] The purpose of this study was to investigate activities of the hip extensors and erector spinae during bridging exercise by using instruments with a laser pointer on the pelvic belt. [Subjects] Twelve subjects (age, 23 to 33 years) with non-specific low back pain volunteered for this study. [Methods] Subjects performed bridging exercises with and without trajectory exercises by using a laser pointer fixed to a pelvic strap. The erector spinae, gluteus maximus and hamstring activities with and without trajectory exercises using a laser pointer were recorded on using electromyography. [Results] Compared to the without laser pointer group, the group that underwent bridging with trajectory exercises using a laser pointer had significantly higher gluteus maximus activity and significantly lower erector spinae activity. Significantly higher gluteus maximus/erector spinae activity ratios were observed when performing trajectory exercises using a laser pointer during bridging exercises. [Conclusion] This result suggests that trajectory exercises using a laser pointer during a bridging exercise would be effective for improving gluteus maximus activity.