Abdominal Activity Research Articles

Effects of Shoulder Abduction in Opposite Directions on EMG Activity in the Abdominal Muscles during Single Leg Raising in the Supine Position on the Foam Roller in Healthy Subjects

Purpose: The purpose of this study was to examine the electromyographic (EMG) activity of the abdominal muscles and to compare the activity ratios of the bilateral rectus abdominis (RA) to oblique abdominal muscles during shoulder abduction in opposite directions with single leg raising (SLR) performed in the supine position on a foam roller. Methods: Fifteen healthy subjects were recruited to the study. Each subject lay on the foam roller and performed left single leg raising with right or left shoulder 90° abduction (Abd); performed in a random order. Surface EMG recordings of selected abdominal muscles (i.e., the RA, external oblique abdominis [EO], internal oblique abdominis [IO], and transverse abdominis [TrA]) were normalized to maximum voluntary isometric contraction. EO/RA and IO and TrA/RA ratios were determined with surface EMG. Data were analyzed by Independent t-test. The statistical significance level was p<0.05. Results: The results were as follows: (1) the right RA, left EO, and right IO and TrA muscle activities increased significantly at the left SLR with left Abd compared to the left SLR with right Abd (p<0.05); and (2) the ratio of right EO/RA activity increased significantly at the left SLR with right Abd compared to left Abd (p<0.05). Conclusion: These findings suggest that left SLR with left Abd on a foam roller is an appropriate exercise for activation of specific oblique abdominal muscles.

The Effects of Various Exercise-Based Interventions on Non-Specific Chronic Low Back Pain: A Systemic Review on Persian Studies

Introduction: Conservative treatment of patients with non-specific chronic low back pain (NCLBP); especially as exercise-based interventions, is a main part of rehabilitation program for such patients. This review study was designed to investigate the influences of exercise-based therapeutic intervention on patients with NCLBP in Persian studies. Materials and Methods: ISC (Islamic World Science Citation Center), Magiran, IranMedex, SID, and MedLib were selected as searching motor engines by using keywords including NCLBP, exercise-based therapy, Therapeutic exercise, Exercise therapy, and Corrective exercise training. Studies which used patients with acute or specific low back pain as subjects were excluded from the review process. Results: From 35 articles found, ten articles included in our study. They mainly concentrated on the effects of core stabilizing exercises and Pilates training on pain intensity, disability, function, balance, lumbar flexor and extensor muscles’ endurance, and electrical activity of abdominal and spinal muscles in individuals with NCLBP. Positive effect of core stabilizing exercises and Pilates training method on above-mentioned variables is confirmed in the literature. Conclusion: Exercise-based therapeutic interventions; especially as core stabilizing exercises or Pilates training can lead to reducing pain and improving function in patients with NCLBP; although designing and implementing clinical trials studies is essential due to relative poor quality of present articles to achieve more valid results.

Traditional posterior load carriage: effects of load mass and size on torso kinematics, kinetics, muscle activity and movement stability

Traditional posterior load carriage (PLC), done without the use of an assistive device (e.g. backpack), has been associated with low back pain (LBP) development. This study evaluated the effects of important task demands, related to load mass and size, on potential mechanisms linking traditional PLC with LBP. Nine healthy participants completed PLC tasks with three load masses (20%, 35% and 50% of individual body mass) and three load sizes (small, medium and large). Torso kinematics, kinetics, muscle activity and slip risk were evaluated during PLC on a walkway, and torso movement stability was quantified during PLC on a treadmill. Increasing load mass caused increased torso flexion, L5/S1 flexion moment, abdominal muscle activity and torso movement stability in the frontal plane. Increasing load size also caused higher torso flexion, peak torso angular velocity and acceleration, and abdominal muscle activity. Complex interactive effects of load mass and size were found on paraspinal muscle activity and slip risk. Specific task demands, related to load mass and size, may thus influence the risk of LBP during PLC.

Bracing of the trunk and neck has a differential effect on head control during gait.

During gait, the trunk and neck are believed to play an important role in dissipating the transmission of forces from the ground to the head. This attenuation process is important to ensure head control is maintained. The aim of the present study was to assess the impact of externally restricting the motion of the trunk and/or neck segments on acceleration patterns of the upper body and head and related trunk muscle activity. Twelve healthy adults performed three walking trials on a flat, straight 65-m walkway, under four different bracing conditions: 1) control-no brace; 2) neck-braced; 3) trunk-braced; and 4) neck-trunk braced. Three-dimensional acceleration from the head, neck (C7) and lower trunk (L3) were collected, as was muscle activity from trunk. Results revealed that, when the neck and/or trunk were singularly braced, an overall decrease in the ability of the trunk to attenuate gait-related oscillations was observed, which led to increases in the amplitude of vertical acceleration for all segments. However, when the trunk and neck were braced together, acceleration amplitude across all segments decreased in line with increased attenuation from the neck to the head. Bracing was also reflected by increased activity in erector spinae, decreased abdominal muscle activity and lower trunk muscle coactivation. Overall, it would appear that the neuromuscular system of young, healthy individuals was able to maintain a consistent pattern of head acceleration, irrespective of the level of bracing, and that priority was placed over the control of vertical head accelerations during these gait tasks.

A user's guide to intra-abdominal pressure measurement.

The intra-abdominal pressure (IAP) measurement is a key to diagnosing and managing critically ill medical and surgical patients. There are an increasing number of techniques that allow us to measure the IAP at the bedside. This paper reviews these techniques. IAP should be measured at end-expiration, with the patient in the supine position and ensuring that there is no abdominal muscle activity. The intravesicular IAP measurement is convenient and considered the gold standard. The level where the mid-axillary line crosses the iliac crest is the recommended zero reference for the transvesicular IAP measurement; moreover, marking this level on the patient increases reproducibility. Protocols for IAP measurement should be developed for each ICU based on the locally available tools and equipment. IAP measurement techniques are safe, reproducible and accurate and do not increase the risk of urinary tract infection. Continuous IAP measurement may offer benefits in specific situations in the future. In conclusion, the IAP measurement is a reliable and essential adjunct to the management of patients at risk of intra-abdominal hypertension.

Comparison of deep and superficial abdominal muscle activity between experienced Pilates and resistance exercise instructors and controls during stabilization exercise.

Pilates and resistance exercises are used for lumbar stabilization training. However, it is unclear which exercise is more effective for lumbar stabilization. In our study, we aimed to compare surface muscle activity and deep muscle thickness during relaxation and spinal stabilization exercise in experienced Pilates and resistance exercise instructors. This study is a retrospective case control study set in the Exercise Prescription Laboratory and Sports Medicine Center. The participants included Pilates instructors (mean years of experience, 3.20±1.76; n=10), resistance exercise instructors (mean years of experience, 2.53±0.63; n=10), and controls (n=10). The participants performed 4 different stabilization exercises: abdominal drawing-in maneuver, bridging, roll-up, and one-leg raise. During the stabilization exercises, surface muscle activity was measured with electromyography, whereas deep muscle thickness was measured by ultrasound imaging. During the 4 stabilization exercises, the thickness of the transverse abdominis (TrA) was significantly greater in the Pilates-trained group than the other 2 other groups. The internal oblique (IO) thickness was significantly greater in the Pilates- and resistance-trained group than the control group, during the 4 exercises. However, the surface muscle activities were similar between the groups. Both Pilates and resistance exercise instructors had greater activation of deep muscles, such as the TrA and IO, than the control subjects. Pilates and resistance exercise are both effective for increasing abdominal deep muscle thickness.

Evaluating Abdominal and Lower-Back Muscle Activity While Performing Core Exercises on a Stability Ball and a Dynamic Office Chair.

The purpose of this study was to evaluate the ability of a dynamic office chair to activate the core muscles while participants performed exercises sitting on the chair compared to a stability ball. Prolonged sitting has become an accepted part of the modern office. However, epidemiological evidence suggests that sedentary postures are linked to many adverse effects on health. The concept of dynamic or active sitting is intended to promote movement while sitting to reduce the time spent in prolonged, static postures. Sixteen participants performed four pelvic rotation exercises (front-back, side-side, circular, and leg lift) on both a dynamic office chair and a stability ball. Muscle activity from 12 torso muscles were evaluated with surface electromyography. For all exercises, trunk muscle activity on the chair was comparable to that on a stability ball. The right external oblique was the only muscle to produce greater peak activity (p = .019) when using the ball compared to the chair (21.4 ± 14.0 percent maximal voluntary excitations (%MVE) and 14.7 ± 10.8 %MVE for the ball and chair, respectively). The left thoracic erector spinae produced greater average activity (p = .044) on the chair than on the ball. These findings suggest that this dynamic sitting approach could be an effective tool for core muscle activation while promoting movement and exercise while sitting at work. Muscle activations on the dynamic chair are comparable to those on a stability ball, and dynamic office chairs can promote movement and exercise while sitting at work.

Recovery of balance is impaired and abdominal muscle activity is increased in chronic obstructive pulmonary disease

Recovery of balance is impaired and abdominal muscle activity is increased in chronic obstructive pulmonary disease

Disturbed muscular adaptation and changed motor strategies in recurrent low back pain patients during stair walking after experimental back-muscle fatigue

Background: The majority of low back pain (LBP) patients experience no symptoms after 4 weeks but up to 70–80% will relapse within one year and up to 40% develops recurrent LBPand reduced functional capacity.Recurrent LBP thereby is a major cause of dysfunction, decreased quality of life and economical expenditures. The evidence on causality is generally low, but motor control is a potential factor linked with LBP. The trunk-muscle activity is affected by pain but the majority of the evidence is based on investigation of non-functional motor tasks. The transfer of results to functional and complex motor tasks is challenged, since the motor output is a result of the interaction between central and peripheral dynamic mechanisms. Experimental fatigue of the backmuscles in healthy and LBP patients affects the control of the trunk and the muscle activity is earlier affected in patients during exercising towards fatigue. Disturbed control of the muscular control can influence the development of LBP but the underlying mechanisms and consequences on motor control during motor tasks requiring motor planning and higher stability and dynamic force development remains unknown. Purpose: To explore the trunk muscle activity and motor task timing in healthy and recurrent LBP patients during stair ascend and descend before and after lumbarmuscle fatiguing. Methods: 45 participants (25 LBP) performed 10 concurrent ascend and descend steps before and after fatiguing the back extensors by repetitive dynamic exercises to exhaustion. 3 ascending and 3 descending gait phases were detected. The duration of the phases and changes in i-EMG activity from surface EMG-recordings of 3 back-, 3 abdominaland 2 gluteus-muscles before and after fatigue were calculated and compared by ANOVA statistics. Results: The duration of the step tasks were shorter in LBP patients before (P< 0.01) and after (P< 0.01) fatiguing the back extensors. Fatigue furthermore resulted in increased duration during phases with preparation of single-leg weightbearing (P< 0.001) and decreased during the weight bearing phases (P< 0.001). Back extensor fatigue resulted in increased back and abdominal muscle activity in healthy (P< 0.01) and unchanged muscle activity in LBP patients in most phases, but during the descend phase with single-legged weight bearing the activity remained unchanged in healthy and decreased in LBP patients (P< 0.001). Conclusion(s): Back extensor muscle fatigue resulted in increased trunk muscle activity in healthy and unchanged trunk muscle activity in LBP patients during stair stepping and the patients could be at higher risk of inappropriate load of potential painful structures. In phases with high stability demands the patients utilized movement strategies that in short-term might reduce the stability demands, but the long-term structural consequence is unknown. Furthermore it remains unknown if these strategies will affect recurrent LBP patients during other functional motor tasks and more research is needed to explore these questions. Implications: Affected control of the spine in high stability demands is important in evaluation of recurrent LBP patients. More research is needed to explore the basic mechanisms and the potential role of motor control during functional motor tasks in LBP development.

Effect of tens on pain threshold: comparison of brief intense mode tens with DNIC

back pain. The study was approved by the Ethics Screening Committee of Tokyo Metropolitan University. We developed two training method. The first was drawin exercise wherein we instructed participants to lower their underwears and draw-in their abdomen using pressure biofeedback beforeMR imaging (draw-in exercise). The second exercise involved participants to maintain the supine position; we then put the LRT band through the big fingers and the first toes and instructed them to extend the LRT band as much as possible (LRT band exercise). Each exercise was to be performed on alternate days. Before exercise, we obtained MRI. The system used was Achieva 3.0 T MRI (Philips Medical Systems, Best, Netherlands). The imaging technique was T2 star (TR= 500ms, TE= 0.703ms, FOV= 480mm). After we scanned, participants did each exercise in MRI. For a duration of 5min, each exercise was performed at an interval of 10 s; MRI was conducted immediately after exercise. The OsiriX imaging software was used for analysis, and we circled region of interest (ROI) transverse abdominalmuscles for each exercise; the mean values in ROI were regarded as MR signal intensities. We compared the results using the t-test after the analysis of variance. The analyses were carried using IBM SPSS ver. 14 with values for p< 0.05 was set as the significance level. Results: In Draw-in exercise, the mean MR signal intensities for transverse abdominal muscles before training was Right side 578.3 (SD 144.6), left side 656.3 (SD 18.6) and the corresponding value after training was Right side 572.7 (SD 125.6), left side 641.8 (SD 142.1). In LRT Band exercise, the mean MR signal intensities for transverse abdominal muscles before training was Right side 582.8 (SD 129.6), left side 649.3 (SD 148.8) and the corresponding value after training was Right side 660.5 (SD 83.3), left side 738.37 (SD 89.4). The activation of transverse abdominal muscles significantly increased in LRT Band exercise Right side (p< 0.02), Left side (p< 0.03). Conclusion(s): The data we collected suggested that the compound motion of trunk and extremities using band is effective as a method to train transverse abdominal muscle. Implications: This result showed the effectiveness of this training method in conditioning the transverse abdominal muscle. The training was easy and safe, so it may be useful for elderly people.

The abdominal drawing-in maneuver to detect activity in the deep abdominal muscles. Is this clinical tool reliable and valid?

The abdominal drawing-in maneuver to detect activity in the deep abdominal muscles. Is this clinical tool reliable and valid?

Comparison of Abdominal and Lumbar Muscles Electromyography Activity During Two Types of Stabilization Exercises

Background:: Stabilization exercises lead to improve muscle performance and can be used to prevent and treat of low back pain. Objectives:: Aim of the present study is to evaluate and compare the level of abdominal and lumbar muscles activity during two types of stabilization exercises. Patients and Methods:: Thirty healthy females aged between 20 - 30 years old participated in this quasi-experimental study. Muscle activity was recorded from Transversus Abdominus (TrA), Internal Oblique (IO) and multifidus on both sides with electromyography (EMG) device during the quadruped and dead bug exercises. EMG data were normalized to the percentage of maximum voluntary isometric contraction and paired t-test was used for statistical analysis. Results:: The mean muscle activity in the right arm reach of quadruped and dead bug exercises showed that right IO and TrA muscles produced greater activity during quadruped exercise (P = 0.015, P = 0.001, respectively). The comparison between the mean muscles activity in the left leg reach of two exercises showed that right and left TrA muscles produced greater activity during left leg reach in quadruped exercise (P = 0.005, P = 0.046, respectively). Also, the comparison between the mean muscle activity in simultaneous movements of left leg and right arm reach in the 2 exercises showed that right TrA muscle was activated at a higher level compared to the other muscles in the quadruped exercise (P = 0.002). Conclusions:: The results showed quadruped exercise can provide stability, coordination, and smoothness of the movements in healthy subjects and all considered muscles participated in this exercise.

Comparison of Abdominal and Lumbar Muscles Electromyography Activity During Two Types of Stabilization Exercises

Background: Stabilization exercises lead to improve muscle performance and can be used to prevent and treat of low back pain. Objectives: Aim of the present study is to evaluate and compare the level of abdominal and lumbar muscles activity during two types of stabilization exercises. Patients and Methods: Thirty healthy females aged between 20 - 30 years old participated in this quasi-experimental study. Muscle activity was recorded from Transversus Abdominus (TrA), Internal Oblique (IO) and multifidus on both sides with electromyography (EMG) device during the quadruped and dead bug exercises. EMG data were normalized to the percentage of maximum voluntary isometric contraction and paired t-test was used for statistical analysis. Results: The mean muscle activity in the right arm reach of quadruped and dead bug exercises showed that right IO and TrA muscles produced greater activity during quadruped exercise (P = 0.015, P = 0.001, respectively). The comparison between the mean muscles activity in the left leg reach of two exercises showed that right and left TrA muscles produced greater activity during left leg reach in quadruped exercise (P = 0.005, P = 0.046, respectively). Also, the comparison between the mean muscle activity in simultaneous movements of left leg and right arm reach in the 2 exercises showed that right TrA muscle was activated at a higher level compared to the other muscles in the quadruped exercise (P = 0.002). Conclusions: The results showed quadruped exercise can provide stability, coordination, and smoothness of the movements in healthy subjects and all considered muscles participated in this exercise.

Serotoninergic Antagonism in the Retrotrapezoid Nucleus Prevents the Expiratory Long‐Term Facilitation Induced by Acute Intermittent Hypoxia

Serotonin (5‐HT) plays an important role in the development of sympathetic and phrenic long‐term facilitation (LTF) elicited by acute intermittent hypoxia (AIH). Herein, we evaluated the role of 5‐HT in the retrotrapezoid nucleus (RTN) on the emergence of active expiratory pattern in response to AIH. Using anesthetized (urethane; 1.2 g/Kg, ip) male Holztmann rats (280‐290 g), we analyzed the changes in the arterial pressure, heart rate and in the diaphragmatic and abdominal (ABD) activities elicited by single and repeated (3 times, 5 min apart) bilateral microinjections of 5‐HT (1mM, 50nl) in the RTN. We also analyzed the effects of bilateral microinjections of ketanserin (5‐HT2A antagonist; 10 µM, 50 nl) in the RTN on the cardiorespiratory changes induced by AIH (10 times of 6‐7% O2, for 45 s, each 5 min). Repeated, but not single, microinjections of 5‐HT in the RTN (n=7) elicited a sustained increase in the abdominal expiratory activity (ΔABD: 85±33%, 60 min after microinjections, P&lt;0.05) that was prevented by previous microinjections of ketanserin. The 5HT2A receptor antagonism in the RTN during AIH exposure also prevented the increase in ABD activity evoked by AIH (ΔEMGABD: 40±9 vs ‐1±1% 60 min after AIH, respectively vehicle and ketanserin; P&lt;0.05). The other cardiorespiratory parameters were not affected by the 5‐HT and the ketanserin microinjections in the RTN. Our results indicate that, in anesthetized conditions, the activation of serotoninergic receptors in the RTN is sufficient to promote a sustained increase in abdominal activity and required for the emergence of expiratory LTF induced by AIH. Supported by FAPESP, CNPq, CAPES and PROPe.

Abdominal Muscle Activity During Exercise Ball, Machine, and Floor Strengthening Exercises

Abdominal Muscle Activity During Exercise Ball, Machine, and Floor Strengthening Exercises

Postural- and respiratory-related activities of abdominal muscles during post-exercise hyperventilation

The present study focuses on the role of superficial abdominal muscles revealed by electromyographic recordings during the maintenance of a bipedal stance perturbed by post-exercise hyperventilation. Twelve healthy subjects performed six 30-s postural tests: one pre-exercise test while breathing quietly, then one test every minute for the 5min immediately following a maximum-intensity, incremental cycling exercise test. Displacement of the centre of pressure in the sagittal plane was monitored over time. Myoelectric activities of the obliquus externus (OE), obliquus internus (OI) and rectus abdominis (RA) muscles were recorded by surface electromyography (EMG). Metabolic parameters were measured with a portable telemetric device. The change in ventilatory drive induced by exercise was accompanied by a significant increase in both postural sway parameters and EMG activities. For OE and OI, the increased EMG activities were prominent during expiration, whereas OI was silent during inspiration. OE and RA were activated during both expiration and inspiration. It is concluded that the compensation of respiratory disturbances of the erect posture appears to be less effective when minute ventilation increases. The patterns of muscle activity suggest that abdominal muscles are controlled differentially and that their functional coordination is dependent on the respiratory demand.

3D point cloud in the evaluation of processes that generate instability of the lumbar spine

OBJECTIVE: To integrate patients with lumbar instability in a multisensor platform in the process of assessment and diagnosis, assigning quantitative parameters for the sagittal balance (SB) and muscle function. METHODS: Experimental study involving adult patients diagnosed with diseases that cause alterations in the SB, that were or were not submitted to surgery with posterior instrumentation and fusion. Each patient underwent anthropometric measurements in body composition scale; a kinesiological analysis using a multisensor platform consisting of depth camera to static/dynamic analysis for the quantitative measurement of SB, and surface electromyography to capture the level of abdominal and lumbar muscles activation and through flexion and extension. RESULTS: Seven adult patients: five females (62.5%)and two men (37.5%) with a mean age 48 years. Images with depth cameras resulted in a SB of from -6.4 to +5.3cm (average -5.7cm). In individuals with positive sagittal balance the percentage of activation (PA) of the abdominal muscles was 58.5% and the lower back lumbar was 75.25%; patients with negative SB integrated the PA of the abdominal muscles of 70.25% and lumbar of 65%; the patient with neutral SB exhibited activation of the abdominal muscles of 87.75% and lumbar muscles of 78.25%. CONCLUSIONS: We observed a trend towards positive SB in patients with overweight and obesity by BMI, as well as increased activation of the abdominal muscles. The multi sensor platform is a useful tool for the diagnosis and prognosis of diseases involving sagittal imbalance.

Maximum expiration activates the abdominal muscles during side bridge exercise.

Recent studies have indicated that maximum expiration could be a useful way of performing challenging exercises that include coactivation of the deep and superficial abdominal muscles. However, little is known about the effect of maximum expiration on the activity of the abdominal muscles during lumbar stabilizing exercise. The purpose of our study was to quantify changes in the activities of the abdominal muscles during side bridge exercise in combination with maximum expiration. Experimental laboratory study. The activities of the rectus abdominis (RA), external oblique (EO), and internal oblique (IO) muscles were measured using electromyography in 12 healthy men performing 3 tasks: holding the breath after maximum expiration in the supine position, holding the breath after resting expiration during side bridge exercise, and holding the breath after maximum expiration during side bridge exercise. Significant increases in the activities of the abdominal muscles (RA, EO, and IO) occurred with maximum expiration when compared with resting expiration during side bridge exercise (P <0.05). This is the first study to demonstrate the effect of maximum expiration on abdominal muscle activities during a stabilizing exercise, thus contributing to existing knowledge about therapeutic exercise for alternative core training.

Changes in Activation of Abdominal Muscles at Selected Angles During Trunk Exercise by Using Ultrasonography.

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

Impact of different body positions on bioelectrical activity of the pelvic floor muscles in nulliparous continent women.

We examined pelvic floor muscles (PFM) activity (%MVC) in twenty nulliparous women by body position during exercise as well as the activation of abdominal muscles and the gluteus maximus during voluntary contractions of the PFMs. Pelvic floor muscle activity was recorded using a vaginal probe during five experimental trials. Activation of transversus abdominis, rectus abdominis, and gluteus maximus during voluntary PFM contractions was also assessed. Significant differences in mean normalized amplitudes of baseline PFM activity were revealed between standing and lying (P < 0.00024) and lying and ball-sitting positions (P < 0.0053). Average peak, average time before peak, and average time after peak did not differ significantly during the voluntary contractions of the PFMs. Baseline PFM activity seemed to depend on the body position and was the highest in standing. Pelvic floor muscles activity during voluntary contractions did not differ by position in continent women. Statistically significant differences between the supine lying and sitting positions were only observed during a sustained 60-second contraction of the PFMs.