Transverse Transport in Two-Dimensional Relativistic Systems with Nontrivial Spin Textures.

Using multiple scattering theory, we show that the generally accepted expression of transverse resistivity in magnetic systems that host skyrmions, given by the linear superposition of the ordinary, the anomalous, and the topological Hall effect, is incomplete and must be amended by an additional term, the "noncollinear" Hall effect (NHE). Its angular form is determined by the magnetic texture, the spin-orbit field of the electrons, and the underlying crystal structure, allowing us to disentangle the NHE from the various other Hall contributions. Its magnitude is proportional to the spin-orbit interaction strength. The NHE is an essential term required for decoding two- and three-dimensional spin textures from transport experiments.

Trunk muscle activation patterns during active hip abduction test during remission from recurrent low back pain: an observational study.

BACKGROUND: The active hip abduction test (AHAbd) is widely used to evaluate lumbopelvic stability, but the onset of trunk muscle activation during the test in individuals with recurrent low back pain (rLBP) has not been investigated so far. It is important to investigate the pattern of trunk muscle activation during the AHAbd test to provide insight into the interpretation of observation-based assessment results; this may help to create exercise therapy interventions, from a movement control perspective, for people seeking treatment for rLBP. The purpose of this study was to compare the timing of trunk muscle activation between individuals with and without rLBP and to assess potential differences. METHODS: Seventeen subjects in remission from rLBP and 17 subjects without rLBP were recruited. We performed surface electromyography of the transversus abdominis/internal abdominal oblique, external oblique, erector spinae, and gluteus medius muscles during the AHAbd test on both sides. The onset of trunk muscle activation was calculated relative to the prime mover gluteus medius. The independent-samples t- and Mann-Whitney U tests were used to compare the onset of trunk muscle activation between the two groups. RESULTS: The onset of transversus abdominis/internal abdominal oblique activation on the ipsilateral (right AHAbd: -3.0 ± 16.2 vs. 36.3 ± 20.0 msec, left AHAbd: -7.2 ± 18.6 vs. 29.6 ± 44.3 ms) and contralateral sides (right AHAbd: -11.5 ± 13.9 vs. 24.4 ± 32.3 ms, left AHAbd: -10.1 ± 12.5 vs. 23.3 ± 17.2 ms) and erector spinae on the contralateral side (right AHAbd: 76.1 ± 84.9 vs. 183.9 ± 114.6 ms, left AHAbd: 60.7 ± 70.5 vs. 133.9 ± 98.6 ms) occurred significantly later in individuals with rLBP than in individuals without rLBP (p < 0.01). During the left AHAbd test, the ipsilateral erector spinae was also activated significantly later in individuals with rLBP than in individuals without rLBP (71.1 ± 80.1 vs. 163.8 ± 120.1 ms, p < 0.05). No significant difference was observed in the onset of the external oblique activation on the right and left AHAbd tests (p > 0.05). CONCLUSIONS: Our results suggest that individuals with rLBP possess a trunk muscle activation pattern that is different from that of individuals without rLBP. These findings provide an insight into the underlying muscle activation patterns during the AHAbd test for people with rLBP and may support aggressive early intervention for neuromuscular control.

Point-of-care procalcitonin may predict the need for surgical treatment in patients with small bowel obstruction.

BACKGROUND: The early identification of patients with small bowel obstruction who require surgical treatment could potentially lead to improved patient outcomes. We evaluated the efficacy of point-of-care procalcitonin for predicting surgical treatment among patients with small bowel obstruction. METHODS: This was a prospective observational study. We measured serum procalcitonin levels in patients who presented to the emergency department and were diagnosed with small bowel obstruction from April 1, 2018 through March 31, 2019. Patients were grouped into two groups: the elevated procalcitonin and normal procalcitonin groups. Our primary outcome was surgical treatment. RESULTS: A total of 53 patients with small bowel obstruction were included in the study, and 11 patients (20.8%) were treated operatively. Baseline characteristics were similar, except for age, between the elevated procalcitonin (≥0.12 ng/ml) and normal procalcitonin groups. The elevated procalcitonin level was significantly correlated with surgical treatment and hospital length of stay (p < 0.05). The sensitivity, specificity, and positive likelihood of procalcitonin for the former were 45.5%, 85.7%, and 5.0 respectively. CONCLUSION: The patients with small bowel obstruction who had elevated procalcitonin levels on presentation showed significantly higher rate of surgical treatment than those who had normal procalcitonin levels. Point-of-care procalcitonin might predict the need for surgical treatment in patients with small bowel obstruction and could be used as an additional diagnostic test. Further studies with more patients are needed to investigate the predictive value of point-of-care procalcitonin for surgical treatment.

Active Chemical Sampling Using Jet Discharge Inspired by Crayfish: CFD Simulations of the Flow Fields Generated by the Jet Discharge Device.

Here, we report on computational fluid dynamics (CFD) simulations conducted to develop a chemical sample collection device inspired by crayfish. The sensitivity of chemical sensors can be improved when used with a sniffing device. By collecting fluid samples from the surroundings, all solute species are also collected for the sensor. Crayfish generate jet-like water currents for this purpose. Compared to simply sucking water, food smells dissolved in the surrounding water can be more efficiently collected using the inflow induced by the jet discharge because of the smaller decay of the inflow velocity with the distance. Moreover, the angular range of water sample collection can be adjusted by changing the directions of the jet discharge. In our previous work, a chemical sample collection device that mimics the jet discharge of crayfish has been proposed. Here, we report CFD simulations of the flow fields generated by the device. By carefully configuring the simulation setups, we have obtained simulation results in which the angular ranges of the chemical sample collection in real experiments is well reproduced. Although there are still some discrepancies between the simulation and experimental results, such simulations will facilitate the process of designing such devices.

Detection of Gas Drifting Near the Ground by Drone Hovering Over: Using Airflow Generated by Two Connected Quadcopters.

This paper describes the utilization of the downwashes of multicopters for gas-sensing applications. Multirotor drones are an attractive platform for sensing applications. Their high maneuverability enables swift scanning of a target area with onboard sensors. When equipped with a gas sensor and used for gas-sensing applications, however, the strong downwash produced by the rotors poses a problem. When a multicopter is hovering at a low altitude, gas puffs leaked from a gas source on the ground are all blown away. Here, we propose to use two multicopters connected by a rod or a string and place a gas sensor at the midpoint of the rod/string. The downwash generated by each multicopter spreads radially after it impinges on the ground. When two multicopters are connected, the airflows spreading radially along the ground from the two multicopters impinge at the center and are deflected in the upward direction. Gas puffs wafting near the ground surface between the two multicopters are carried by this upward airflow to the gas sensor. Experimental results are presented to show the soundness of the proposed method. The connected quadcopters hovering over an ethanol gas source was able to detect the gas even with a moderate cross-flow.

Posteroanterior Segmental Displacement of the Lumbar Spine: Assessment Using Ultrasound in Asymptomatic Men.

OBJECTIVE: This study aimed to assess posteroanterior (PA) segmental displacement of the lumbar spine using ultrasound (US). METHODS: Eight asymptomatic male participants (20.1 ± 0.4 years) were included in this study. The relative depth between the tip of the L4 and L3 spinous processes from the US probe (mm) was measured using US in the following 7 conditions, which were without PA force, applying PA force of 9.8 newton (N), 19.6 N, 29.4 N, 39.2 N, 49.0 N, and 58.8 N to both sides of the L4 costal processes. The measurements were repeated twice within a day. The intraclass correlation coefficient, standard error of measurement (SEM), and minimal detectable change (MDC) were calculated. A repeated-measures analysis of variance was also used to determine the influence of PA force on the relative depth. RESULTS: The intraclass correlation coefficients for the intrarater reliability of the 7 conditions were 0.95 (SEM: 0.43 mm, MDC: 1.19 mm), 0.93 (SEM: 0.45 mm, MDC: 1.25 mm), 0.93 (SEM: 0.47 mm, MDC: 1.30 mm), 0.95 (SEM: 0.37 mm, MDC: 1.02 mm), 0.95 (SEM: 0.40 mm, MDC: 1.10 mm), 0.96 (SEM: 0.38 mm, MDC: 1.04 mm), and 0.95 (SEM: 0.42 mm, MDC: 1.15 mm), respectively. The intrarater reliability of the relative depth using US was reliable. There was no significant change in the relative depth among the 7 conditions (F = 0.88, P = .41). Incrementally greater PA force was not related to greater intersegmental translation. CONCLUSION: Our US method could not detect PA segmental displacement of the lumbar spine.

Non-surgical management in hemodynamically unstable blunt traumatic pericardial effusion: A feasible option for treatment.

INTRODUCTION: Little is known about the outcomes of deliberate non-surgical management for hemodynamically unstable patients with blunt traumatic pericardial effusion. We evaluated the efficacy of management with pericardiocentesis or subxiphoid pericardial window in hemodynamically unstable patients who reach the hospital alive with blunt traumatic pericardial effusion. METHODS: We conducted a review of a consecutive series of patients with pericardial effusion following blunt trauma who arrived at Fukui Prefectural Hospital between January 1, 2009 and December 31, 2017. All patients with traumatic pericardial effusion were included, irrespective of the type of blunt trauma. RESULTS: Eleven patients were identified arrived to the Emergency Department with a pericardial effusion after blunt trauma. Of the eleven patients, five patients had cardiopulmonary arrest on arrival and none survived. Of the other six patients who reached the hospital alive, five were hemodynamically unstable and clinically diagnosed with cardiac tamponade. One patient was hemodynamically stable and managed conservatively without pericardiocentesis or pericardial window. Otherwise, two patients were managed with pericardiocentesis alone. One patient was managed with pericardial window alone. One was managed with both pericardiocentesis and pericardial window. The remaining patient underwent median sternotomy because of unsuccessful pericardial drainage tube insertion. All six patients who reached the hospital alive survived. Five patients did not require surgical repair. CONCLUSION: The results of the present study suggested that non-surgical management of hemodynamically unstable patients who reach hospital alive with blunt pericardial effusion may be a feasible option for treatment.

Displaced anterior pelvic fracture on initial pelvic radiography predicts massive hemorrhage.

INTRODUCTION: Massive hemorrhage is often associated with unstable pelvic fractures with posterior ring injury. Initial pelvic radiography alone may not detect these posterior lesions. We examined whether the presence of an anterior pelvic fracture on initial pelvic radiography alone may identify patients who are at a high risk of major hemorrhage. MATERIALS AND METHODS: A total of 288 patients with pelvic fractures were admitted to the Fukui Prefectural Hospital during an 11-year period. After excluding 33 patients who were in cardiopulmonary arrest on arrival and nine with concomitant abdominal organ injuries requiring emergency laparotomy, 246 eligible patients were retrospectively reviewed. Anterior pelvic fractures were defined as displacement of the obturator ring, obturator ring with laterality, or displacement of the pubic symphysis on pelvic radiography. RESULTS: Massive hemorrhage was identified in 106 of 246 patients. Patients with massive hemorrhage had a higher frequency of anterior pelvic fractures on pelvic radiography and higher frequency of posterior pelvic fractures on computed tomography than those without massive hemorrhage. Logistic regression analysis identified displacement of the obturator ring by ≥5mm, obturator ring with laterality of ≥5mm, and displacement of the pubic symphysis by ≥4mm on pelvic radiography as predictors of massive pelvic hemorrhage. CONCLUSION: The results of the present study suggested that the presence of displaced anterior lesions of the pelvic ring on pelvic radiography alone, without the use of computed tomography during the initial treatment stage, may promptly identify patients at high risk of massive pelvic hemorrhage who require intervention for hemorrhage control.

Application of Convolutional Long Short-Term Memory Neural Networks to Signals Collected from a Sensor Network for Autonomous Gas Source Localization in Outdoor Environments.

Convolutional Long Short-Term Memory Neural Networks (CNN-LSTM) are a variant of recurrent neural networks (RNN) that can extract spatial features in addition to classifying or making predictions from sequential data. In this paper, we analyzed the use of CNN-LSTM for gas source localization (GSL) in outdoor environments using time series data from a gas sensor network and anemometer. CNN-LSTM is used to estimate the location of a gas source despite the challenges created from inconsistent airflow and gas distribution in outdoor environments. To train CNN-LSTM for GSL, we used temporal data taken from a 5 × 6 metal oxide semiconductor (MOX) gas sensor array, spaced 1.5 m apart, and an anemometer placed in the center of the sensor array in an open area outdoors. The output of the CNN-LSTM is one of thirty cells approximating the location of a gas source. We show that by using CNN-LSTM, we were able to determine the location of a gas source from sequential data. In addition, we compared several artificial neural network (ANN) architectures as well as trained them without wind vector data to estimate the complexity of the task. We found that ANN is a promising prospect for GSL tasks.

Tape measure-based real-time feedback during the abdominal draw-in maneuver facilitates isolated transverse abdominal contraction.

[Purpose] Although the abdominal draw-in maneuver improves delayed onset of transverse abdomen in patients with low back pain, it is difficult to perform. We investigated whether the maneuver with tape measure-based feedback was more effective in facilitating isolated transverse abdominal muscle contractions than that without feedback in healthy participants. [Participants and Methods] Twenty healthy males performed the maneuver without feedback (control condition) and then with feedback using a tape measure (tape measure condition) in the crook lying, sitting, and standing positions. A B-mode ultrasonography imaging system was used to determine lateral abdominal muscle thicknesses, the percent changes from before the maneuver were calculated for each condition, and the main effects and interactions for each tested muscle were determined. [Results] The percent change in the thickness of the transverse abdominal muscle was significantly greater under the tape measure condition than under the control condition. The percent change in internal oblique thickness during the maneuver was significantly greater in the standing position than in the crook lying or sitting positions. Significant condition-by-position interactions were not observed for any of the examined muscles. [Conclusion] The abdominal draw-in maneuver with tape measure-based feedback may be more effective at facilitating isolated transverse abdominal contractions in all the positions than that without feedback.

Clinical characteristics of external iliac artery branch injury in pelvic trauma.

INTRODUCTION: The clinical characteristics of an injury of external iliac artery branches in blunt pelvic trauma have not yet been sufficiently studied. We evaluated the relationship between injury characteristics and the presence of an injury to external iliac artery branches in blunt pelvic trauma. MATERIALS AND METHODS: A retrospective review of patients admitted with blunt pelvic trauma was conducted over an 11-year period. Charts were reviewed for age, gender, injury characteristics, injury severity score, length of stay in the intensive care unit, transfusion requirements, and fracture pattern. RESULTS: Of 286 blunt pelvic trauma patients, 90 patients (31%) underwent pelvic angiography. Of those patients, 10 (11%) had the injuries of the branches of external iliac artery and 88 (97%) had the injuries of the branches of internal iliac artery. Those patients with external iliac artery branch injuries were significantly associated with hemodynamic instability, when compared to those without external iliac artery branch injuries. There were no significant differences between the patients with and without external iliac artery branch injury with regard to the anatomical characteristics of pelvic trauma. CONCLUSION: Blunt pelvic trauma with hemodynamic instability may be associated with concomitant external iliac artery branch injury.

Comparison of abdominal muscle activity and peak expiratory flow between forced vital capacity and fast expiration exercise.

[Purpose] The purpose of this investigation was to compare the activities of the abdominal muscles and peak expiratory flow between forced vital capacity and fast expiration exercise. [Subjects and Methods] Fifteen healthy male participated in this study. Peak expiratory flow and electromyographic activities of the rectus abdominis, external oblique, and internal oblique/transversus abdominis muscles were measured during forced vital capacity and fast expiration exercise and then peak amplitude and its appearance time were obtained. [Results] Peak expiratory flow values were significantly higher during fast expiration exercise than during forced vital capacity. The internal oblique/transversus abdominis muscles showed significantly higher peak amplitude during fast expiration exercise than during forced vital capacity. However, there were no significant differences between forced vital capacity and fast expiration exercise in the rectus abdominis and external oblique muscles. There was no difference in the appearance time of the peak amplitude between forced vital capacity and fast expiration exercise in any muscle. [Conclusion] Fast expiration exercise might be beneficial for increasing expiratory speed and neuromuscular activation of the internal oblique/transversus abdominis muscles compared to forced vital capacity. These findings could be considered when recommending a variation of expiratory muscle strength training as part of pulmonary rehabilitation programs.

Influence of the ultrasound transducer tilt on muscle thickness and echo intensity of the rectus femoris muscle of healthy subjects.

[Purpose] This study aimed to assess the influence of ultrasound (US) transducer tilt on muscle thickness and echo intensity of the rectus femoris muscle (RF) in healthy subjects. [Subjects and Methods] Fourteen healthy male subjects (20.8 ± 0.8 years) participated in this study. Transducer tilt was measured during US, with a digital angle gauge. Muscle thickness and echo intensity were measured in 4 transducer tilt conditions: reference angle; +3°; +6°; and +9° cranial from the reference angle. [Results] All differences in transducer tilt relative to the reference condition were larger than the minimal detectable change (MDC) of the reference condition. All differences in muscle thickness relative to the reference condition were not larger than the MDC of the reference condition. All differences in the echo intensity relative to the reference condition, except between the reference and the +3° condition, were larger than the MDC of the reference condition. [Conclusion] Our results indicated that an examiner should maintain a precise transducer tilt during repeated US measurements to quantify the minimal change in the echo intensity of the RF.

Blunt thoracic aortic injury with small pseudoaneurysm may be managed by nonoperative treatment.

OBJECTIVE: The efficacy of nonoperative management of blunt thoracic aortic injury (BTAI) was evaluated in patients with pseudoaneurysm. METHODS: A retrospective review was done for patients with BTAI at Fukui Prefectural Hospital during a 9-year period. Charts were reviewed for age, gender, Injury Severity Score, Abbreviated Injury Scale for each body area, initial type of aortic injury, site of aortic injury, type of definitive management, complications, and outcomes. RESULTS: Eighteen patients with BTAI were treated at Fukui Prefectural Hospital. Of 18 patients with pseudoaneurysm, seven patients were hemodynamically unstable and four patients died because of associated injuries; there were no aortic-related deaths. All 14 surviving patients were followed up for an average of 40.9 months. Only two patients with pseudoaneurysm required operative management because of the progression of the pseudoaneurysm. The pseudoaneurysm/normal aortic diameter ratio of those with any intervention was higher than that of those with nonoperative management. CONCLUSIONS: BTAI with pseudoaneurysm can be managed nonoperatively, with about 10% risk of progression to require surgical repair.

Characteristics and diagnostic pitfalls of spontaneous visceral artery dissection in the emergency department.

BACKGROUND: Spontaneous visceral artery dissection (VAD) is a rare disease that mainly occurs in the superior mesenteric artery and celiac artery. However, VAD has been detected more frequently in the past several years because of the increasing use of computed tomography (CT) for the evaluation of abdominal symptoms. A prompt diagnosis and referral to a specialist should be made, because VAD occasionally causes critical bowel ischemia. However, there is no well-established management approach. We performed a retrospective analysis to evaluate the characteristics and prognoses of patients diagnosed with VAD. METHODS: We retrospectively examined data on patients who visited the Emergency Department (ED) at Fukui Prefectural Hospital, and were diagnosed with VAD using enhanced CT scanning from April 2004 to March 2015. All data were collected from the hospital's electronic medical records. We analyzed the clinical characteristics, comorbidity, risk factors, imaging findings, and treatment of patients. RESULTS: Fifty-six patients were identified (superior mesenteric artery: 40 patients, celiac artery: 16 patients). The median age of the patients was 54 years (range, 32-86 years) and 89.3% were men. The majority of the patients complained of abdominal pain (37 patients, 66%). Thirty-nine of the patients (69.6%) were hospitalized. All hospitalized patients received conservative treatment initially. Three patients received endovascular therapy, and 2 patients received surgery. No fatal cases were observed. Twenty-eight patients presented with ED at their initial visit, and 8 cases (29%) were undiagnosed on their initial visit by emergency physicians, though enhanced CT scans were obtained. CONCLUSION: Patients with VAD often present with sudden onset abdominal pain. Most patients were managed successfully with conservative treatment. No fatal cases were observed; however, some cases were missed, even with an enhanced CT scan. It is necessary to include VAD among the differential diagnoses of acute abdominal pain. Patients with VAD should be referred to a specialist, because this disease occasionally causes critical bowel ischemia, necessitating surgical intervention.

Effects of fast expiration exercises without pressure on the respiratory muscle strength of healthy subjects.

[Purpose] The aim of this investigation was to determine the effects of 4 weeks of fast expiration exercises performed without pressure on respiratory muscle strength. [Subjects and Methods] Respiratory muscle strength of the training group that performed fast expiration exercises (n=12) was compared with that of a control group that performed no exercises (n=12). The fast expiration exercises were performed using a peak expiratory flow meter device and consisted of 20 fast expiration exercises performed 3 times per week for 4 weeks. Maximal expiratory and inspiratory pressures were evaluated as respiratory muscle strength using a spirometer pre- and post- intervention. [Results] There were significant increases in maximal expiratory pressure from 76.9 ± 29.1 to 96.1 ± 37.5 cmH2O and maximal inspiratory pressure from 80.8 ± 36.6 to 95.3 ± 37.6 cmH2O in the training group, but there was no significant difference in respiratory muscle strength between pre- and post-intervention in the control group. [Conclusion] Fast expiration exercises may be beneficial for increasing respiratory muscle strength. The findings of this study should be considered when prescribing a variation of the expiratory muscle strength training, as part of a pulmonary rehabilitation program.

Correlation Between Abdominal Muscle Thickness and Maximal Expiratory Pressure.

OBJECTIVES: The activity of abdominal muscles mainly produces high expiratory pressure. These include the rectus abdominis, external oblique, internal oblique, and transverse abdominis muscles. The purpose of this study was to determine whether maximal expiratory pressure is associated with each abdominal muscle thickness at rest. METHODS: Thirty-nine healthy male volunteers (mean age ± SD, 20.7 ± 2.7 years) participated in the study. The thickness of the right rectus abdominis, external oblique, internal oblique, and transverse abdominis muscles was measured by B-mode sonography in the supine position. The maximal expiratory pressure was obtained with a spirometer in the sitting position. The correlations between each abdominal muscle thickness and maximal expiratory pressure were determined by the Pearson correlation coefficient. RESULTS: The correlation coefficient between the rectus abdominis muscle and maximal expiratory pressure was 0.571 (P< .001). Correlation coefficients between the external oblique, internal oblique, and transverse abdominis muscles and maximal expiratory pressure were 0.297 (P = .066), 0.267 (P = .100), and 0.022 (P = .894), respectively. CONCLUSIONS: Our results indicate that the rectus abdominis muscle thickness might be more highly correlated with expiratory pressure production than the external oblique, internal oblique, and transverse abdominis muscle thickness.

Effect of abduction and external rotation of the hip joint on muscle onset time during prone hip extension with knee flexion.

[Purpose] This study investigated the effect of hip position on muscle onset time during prone hip extension with knee flexion. [Subjects] The study included 21 healthy male volunteers. [Methods] Muscle onset times of the right gluteus maximus, right hamstrings, bilateral lumbar erector spinae, and bilateral lumbar multifidus were measured using surface electromyography during right hip extension with knee flexion in the prone position. Measurements were made with the hip in 3 positions: (1) neutral, (2) abduction, and (3) abduction and external rotation. [Results] Gluteus maximus onset relative to the hamstrings was significantly earlier with hip abduction and with hip abduction and external rotation compared with that with the hip in the neutral position. Gluteus maximus onset relative to the hamstrings was significantly earlier with hip abduction and external rotation compared with that with hip abduction. The bilateral multifidus and left lumbar erector spinae onset times relative to the hamstrings were significantly earlier with hip abduction and external rotation compared with those with hip abduction and with the hip in the neutral position. [Conclusion] Abduction and external rotation of the hip during prone hip extension with knee flexion is effective for advancing the onset times of the gluteus maximus, bilateral multifidus, and contralateral lumbar erector spinae.

Correlation between Peak Expiratory Flow and Abdominal Muscle Thickness.

[Purpose] The purpose of this study was to determine whether forced expiration is correlated with abdominal muscle thickness. [Subjects] Twenty-three healthy male volunteers participated in this study. [Methods] The peak expiratory flow (PEF) was obtained using a peak flow meter with subjects in the sitting position. The thicknesses of the right rectus abdominis, external oblique, internal oblique, and transverse abdominis muscles were measured using B-mode ultrasonography at the end of a relaxed expiration in the supine position. [Results] Among the abdominal muscles, only the thickness of the external oblique muscle displayed a significant correlation with PEF. [Conclusion] It appears that the thickness of the external oblique muscle might be associated with PEF during forced expiration.

Slow Expiration Reduces External Oblique Muscle Activity during Maximum Trunk Flexion.

[Purpose] The purpose of this study was to demonstrate the effects of expiration on abdominal muscle activity during maximum trunk flexion. [Subjects] Twenty-one healthy university students (10 men, 11 women) participated in this study. [Methods] Electromyography (EMG) was used to quantify the activity of the right rectus abdominis, external oblique, and internal oblique muscles. The paired t-test was used to examine the significance of differences in the abdominal muscles between maximum trunk flexion with breath holding and slow expiration. [Results] There was a significantly lower EMG activity in the external oblique muscle during maximum trunk flexion with slow expiration. [Conclusion] The results of this study indicate that slow expiration reduces external oblique muscle activity during maximum trunk flexion performed by healthy young subjects.