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Changes in intra-abdominal pressure and spontaneous breath volume by magnitude of lifting effort: Highly trained athletes versus healthy men

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Abstract

Intra-abdominal pressure (IAP) is closely related to breathing behavior during lifting. Abdominal muscles contribute to both IAP development and respiratory function. The purpose of this study was to examine whether spontaneous breath volume and IAP altered with increased isometric lifting effort, and to compare the effect of different abdominal muscle strengths on these parameters. Maximal IAP during the Valsalva maneuver (maxIAP) and maximal isometric trunk flexor strength were measured in 10 highly trained judo athletes (trained) and 11 healthy men (controls). They performed isometric lifting with 0 (rest), 30, 45, 60, 75, 90, and 100% of maximal lifting effort (MLE). Natural inspiratory and expiratory volumes were calculated from air-flow data immediately before and after the start of lifting. IAP, measured using an intra-rectal pressure transducer during lifting, was normalized by maxIAP (%maxIAP). Trained athletes had higher maxIAP and stronger trunk flexor muscles than controls. A significant main effect of lifting effort was found on %maxIAP and respiratory volume. An interaction (lifting effort by group) was found only for %maxIAP. No significant group main effect or interaction was found for respiratory volume. Inspiratory volume increased significantly from tidal volume to above 60 and 45% of MLE in trained athletes and controls, respectively. Expiratory volume decreased significantly from tidal volume at above 30% of MLE in both the groups. These results suggest that spontaneous breath volume and IAP development are coupled with increased lifting effort, and strong abdominal muscles can modify IAP development and inspiratory behavior during lifting.

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... High peak pressures occur during everyday activities, such as sports or coughing. Pressures of more than 200 mmHg can develop for less than 1 s [4,5]. One third of our patients cough more than 400 times in the first 24 h postoperatively [6]. ...
... The exact parameters applied in each experimental series (ES [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] are listed on the left half of Table 2. On the right side of Table 2 the investigated variations for each series are specified. Here, each associated series is marked with an "x". ...
... (4) The paper properly credits the meaningful contributions of co-authors and co-researchers. (5) The results are appropriately placed in the context of prior and existing research. (6) All sources used are properly disclosed. ...
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Purpose Incisional hernias often follow open abdominal surgery. A small-stitch–small-bite suture might close the incision durably. We analyzed specific details of this closure technique and assessed their influence on the closure stability. Methods The effects of cyclic loads, simulating coughs were investigated on a bench test. We prepared porcine bellies in the median line and bovine flanks parallel to the muscle fibers with 15 cm long incisions. Then we punched round or rhomboid defects with a diameter of 5–10 cm into the center of the incision. Monomax® 2–0 and Maxon® 1 and 2–0 were used as suture materials. We tested the durability of the closure with pressure impacts of 210 mmHg repeated 425 times. Throughout the experiments, we modified the suturing technique, the surgeon, the tissue tension, the defect size and shape and the suture diameter. Results Standardizing the suture technique improved the durability of the closure significantly. Any other variations showed minor influences after standardization. All incisions with round defects up to 7.5 cm width withstood 425 impacts using standardized suturing. Unstandardized sutures failed in all cases. When closing an incision with a 10 cm wide defect, the tissues ruptured frequently next to the suture line. We defined criteria to standardize this suturing technique. For the first time, we developed a suture factor related to the durability of a sutured tissue closure. We integrated the suture factor into the concept of biomechanically durable repairs. Conclusions Suturing the abdominal wall with a standardized suturing technique improves its durability significantly.
... Thirteen studies reported IAP from the VM alone, with 6 of these studies also reporting IAP during resistance exercise without being instructed to perform a VM (14,22,28,38,39,51). Two studies reported IAP from a VM during resistance exercise (12,40). ...
... Two studies reported IAP from a VM during resistance exercise (12,40). Of the 14 available studies, 6 were in maleonly cohorts (11)(12)(13)22,28,39), 6 studies combined males and females (7,9,14,15,40,51), and 2 studies did not report sex (18,38). Two studies examining IAP from the VM were undertaken in trained individuals (weightlifters and judo fighters) (14,28), whereas most studies were performed in individuals who did not participate in regular resistance training or activities involving exposure to heavy trunk loads, that is, body contact sports. ...
... Of the 14 available studies, 6 were in maleonly cohorts (11)(12)(13)22,28,39), 6 studies combined males and females (7,9,14,15,40,51), and 2 studies did not report sex (18,38). Two studies examining IAP from the VM were undertaken in trained individuals (weightlifters and judo fighters) (14,28), whereas most studies were performed in individuals who did not participate in regular resistance training or activities involving exposure to heavy trunk loads, that is, body contact sports. Measurement of IAP was most commonly performed intragastrically (9 studies) (7,(11)(12)(13)(14)(15)22,38,51) with 2 studies measuring intrarectally (28,39), 2 by telemetry tablet (18,40), and 1 intravesically (9). ...
Article
During resistance exercise, a brief Valsalva maneuver (VM) is unavoidable when lifting heavy loads (>80% of maximal voluntary contraction) or when lifting lighter loads to failure. It has been proposed that the performance of the VM during resistance exercise increases the stability of the spine due to augmented intra-abdominal pressure (IAP). However, resistance trainers are often advised to avoid the VM during resistance exercise due to potential adverse vascular events. The aim of this review was to establish the effect of the VM on IAP and to evaluate if the VM during resistance exercise is a safe practice. Relevant databases were searched to examine the effect of the VM on: 1) IAP; and 2) hemodynamics during resistance exercise and reported adverse events. The data show that the VM alone increases IAP and that the VM augment IAP during various resistance exercises. An incremental rise in IAP was observed as the lifting intensity and effort increased, with IAP tending to be lower compared with peak IAP from the VM alone. The VM was associated with an increase in blood pressure during resistance exercise, but the VM alone was associated with greater haemodynamic changes. In conclusion, the VM effectively increases IAP, which may assist with spine stability and trunk rigidity during resistance exercise. The health risks associated with the VM during resistance exercise remain unconfirmed.
... The relative IAP generated during activities requiring less effort can then be calculated as a percentage of IAP STRAIN . 12 This could provide a context for understanding the effect of IAP on a particular individual. ...
... Observing the highest IAP during seated strain is consistent with the work of others. 8,12,18 Statistical Analyses Median (interquartile range) values for absolute IAP for the original population from which this current study population was derived have been previously published. 10 In the current study, we present mean, SD, and minimal and maximal values for absolute IAP values (Table 1). ...
... To our knowledge, only one prior study described relative IAP and used Valsalva to characterize maximal IAP. 12 In this study of male judo athletes and controls, athletes had higher measures of muscular fitness and maximal IAP than controls. Although the absolute IAP during progressive lifting was not different between groups, the relative IAP was significantly lower in athletes; that is, they required lower relative IAP to achieve a similar lifting effort. ...
Article
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Objectives: Intra-abdominal pressure (IAP) increases during physical activity. Activities with high IAP are often restricted for women because of potential pelvic floor overloading. Researchers categorize high IAP activities using absolute values (in centimeters of water). Although essential for descriptive purposes, absolute IAP may not be ideal for individualized exercise recommendations. For oxygen consumption, a well-established measure of fitness, exercise scientists use a percentage of the maximal value observed during exercise to create relative exercise intensity prescriptions for an individual. Relative exercise intensity correlates inversely to the maximal value observed. We explore whether this approach and response pattern extend to IAP observed during exercise. Methods: Fifty-five women completed 16 exercises while wearing a vaginal sensor to measure IAP. The highest mean IAP occurred during seated Valsalva/strain (IAPSTRAIN). We calculated relative IAP (in percent) for each participant by dividing the maximal IAP during each exercise by IAPSTRAIN. We examined relationships between relative IAP and IAPSTRAIN for each activity using Pearson r correlations. Results: Mean age was 30.4 ± 9.4 years, and body mass index was 22.4 ± 2.6 kg/m. For most women, IAP was greater during strain than during exercises. Relative IAPs negatively correlated with IAPSTRAIN. Excluding one exercise because of small sample sizes, r for all others ranged from -0.35 to -0.80, all statistically significant. Conclusions: The relative IAP responses to many exercises exhibit an inverse relationship to the highest IAP values during strain, consistent with other variables measured during exercise. Relative IAP may provide an alternative to absolute IAP in understanding IAP's effect on pelvic floor health.
... One of the ways for changing IAP during a given task is controlling lung volume by changing breathing state. Intraabdominal pressure has been shown to vary with breathing state and lung volume (11,14,15). This is because the diaphragm contraction intensity is proportional to the lung volume (i.e., depth of inspiration) (2,7) and plays a significant role in producing high IAP (7,11). ...
... Intraabdominal pressure has been shown to vary with breathing state and lung volume (11,14,15). This is because the diaphragm contraction intensity is proportional to the lung volume (i.e., depth of inspiration) (2,7) and plays a significant role in producing high IAP (7,11). To test the aforementioned hypothesis, this study investigated IAP and muscle strength of hip and knee extensor and flexor in 3 different breath-hold conditions (i.e., 3 different depths of inspiration). ...
... Intra-abdominal pressure was obtained using a sterilizing pressure transducer (MPC-500; Millar Instruments, Houston, TX, USA). The transducer was placed in the rectum about 15 cm from the anus in accordance with previous studies (11,21). Before the test, the pressure transducer was calibrated with a transducer control unit (TCB-500; Millar Instruments). ...
Article
Tayashiki, K, Kanehisa, H, and Miyamoto, N. Does intra-abdominal pressure have a causal effect on muscle strength of hip and knee joints? J Strength Cond Res XX(X): 000-000, 2018-It remains unclear whether intra-abdominal pressure (IAP) has a causal effect on lower-limb muscle strength. This study aimed to clarify whether or not changes in IAP, induced by changing breathing state, influence muscle strength of hip and knee extensor and flexor. Eighteen healthy males (age: 22.0 ± 2.2 years, height: 1.71 ± 0.03 m, and body mass: 68.1 ± 6.1 kg) performed maximal voluntary isometric contractions (MVICs) of hip and knee extensor and flexor during breath-hold at full inspiration (inspiratory condition) or expiration (expiratory condition), or during normal breath-hold (normal condition). Intra-abdominal pressure was obtained by a pressure transducer placed in the rectum and determined at the time at which the developed torque reached to the maximum. The IAP during each MVIC was significantly greater in inspiratory condition than in expiratory condition (p < 0.05). The maximal torque of hip extensor was significantly greater in inspiratory condition than in expiratory condition (p < 0.05). By contrast, the maximal torque of each of hip flexor, knee extensor, and knee flexor was not different among the 3 breath-hold conditions. The IAP was significantly correlated with the maximal torque of hip extensor in each breath-hold condition. The current results suggest that a sufficient increase in IAP has a causal effect to specifically improve muscle strength of hip extensor.
... Finally, 16 studies were included after all the eligibility processes had been completed (Table 1). One study performed the measurement of ITP and IAP simultaneously [18], 8 studies measured IAP by itself [19][20][21][22][23][24][25][26] and 7 studies measured ITP by itself [7,9,16,17,[27][28][29] (Table 2). From seven studies that measured ITP, 3 of them measured mouth pressure, which is commonly presented as ITP, and two studies [17,27] used mouth pressure as the exercise intensity measure (instead of the lifted load). ...
... [34]. Therefore, regarding the progressivity of exercise selection (from easier to more difficult), we recommend considering not only the exercise technique [35] and lifted load [22,23] but also the exercise effect on body pressures; for example, highintensity squats should be incorporated in resistance training programmes after mastering less challenging exercise tasks. Thus, high loaded squats should be recommended only in a resistance-trained population. ...
Article
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The Valsalva manoeuvre, intra-abdominal pressure (IAP) and intrathoracic pressure (ITP) play important roles in resistance training and common daily activities. The purpose of this review is to summarize the ITP and IAP responses to resistance exercises and to determine which exercises elicit the highest or lowest body pressure values under high-intensity resistance exercise. The PubMed, Scopus and Web of Science databases were searched until November 1, 2018. A combination of the following search terms was used: Valsalva manoeuvre, hold breath, controlled breathing, controlled breath, abdominal pressure, intrathoracic pressure AND weight training, resistance exercise, power lifting. The search process yielded 1125 studies, of which 16 were accepted according to the selection criteria and methodological quality. The highest IAP was recorded during squats (over 200 mmHg) followed by deadlift, slide row and leg press (161-176 mmHg), and the lowest IAP was found during bench press (79±44 mmHg). The highest ITP was elicited by the leg press, deadlift and box lift (105-130 mmHg), which were higher than during the bench press (95±37 mmHg) and slide row (88±32 mmHg). We recommend the bench press and slide row as exercises useful for beginners and individuals with hypertension. Untrained individuals should not use heavy squats, deadlift, box lift and clean exercises until they have undergone progressive adaptation for lifting high loads resulting in high IAP and ITP. The values of IAP and ITP during high-intensity exercise seem to be determined mutually by the position of the human body and the external load.
... Our recent study showed that the maximal intra-abdominal pressure (IAP) during abdominal bracing was greater than during trunk flexion, trunk extension, and abdominal hollowing exercises . IAP is considered to be an important factor not only for enhancing the stability and stiffness of the spine (Essendrop et al. 2002;Essendrop and Schibye 2004), but also for generating muscle force during kinetic chain activities such as lifting (Kawabata et al. 2010). Taking these findings into account together with the aforementioned concept of core stabilization training, it is likely that a training program that includes abdominal bracing can be an efficacious modality for improving the strength and power of the trunk and lower limb muscles by increasing IAP. ...
... Hodges et al. (2001) found that, when IAP was electrically increased, a trunk extensor moment also increased. IAP production is considered to be an important factor for force production during kinetic chain activities such as lifting (Kawabata et al. 2010). In addition, the rate of IAP rise plays an important role in stabilizing the lumbar spine during fast movements (Kawabata et al. 2014). ...
Article
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Purpose It is unknown whether maximal voluntary co-contraction of abdominal muscles, called abdominal bracing, can be a training maneuver for improving strength and power of trunk and lower limb muscles. The present study aimed to elucidate this. Methods Twenty young adult men (23.3 ± 1.8 years) were allocated to training (TG, n = 11) or control (CG, n = 9) group. TG conducted an 8-week training program (3 days/week) consisting of 2-s maximal abdominal bracing followed by 2-s muscle relaxation (5 × 10 repetitions/day). Maximal voluntary isometric strength during trunk flexion and extension, hip extension, and knee extension, maximal lifting power from sitting position, and the thicknesses of abdominal muscles were measured before and after the intervention. In addition, surface electromyograms from trunk and lower limb muscles and intra-abdominal pressure (IAP) during the maximal abdominal bracing and maximal lifting tasks were also determined. Results After the intervention, TG showed significant increases in isometric trunk extension (+14.4 %) and hip extension (+34.7 %) strength and maximal lifting power (+15.6 %), while CG did not show any changes in strength and power variables. Furthermore, TG had significant gains in the muscle thickness of the oblique internal (+22.4 %), maximal IAP during abdominal bracing (+36.8 %), and the rate of IAP rise during lifting task (+58.8 %), without corresponding changes in CG. Conclusion The current study indicates that a training style with maximal voluntary co-contraction of abdominal muscles can be an effective maneuver for increasing strength and power during movements involving trunk and hip extensions, without using external load.
... The disadvantage is the high purchase price (Pfeifer and Oliveira, 2006). Such IAP recording has been reported in many studies exploring IAP changes in various postural situations (Kawabata et al., 2010;Sapsford et al., 2013). IAP measurement has also been combined with simultaneous electromyography or ultrasound assessments of core muscles. ...
... The participants voluntarily expand the abdominal wall towards all four sensors, keeping the abdominal cavity pressurized during the entire respiratory cycle . With this scenario, the participant must be able to combine the respiratory and postural functions of the diaphragm, which is a frequent problem in clinical practice (Kawabata et al., 2010;Shirley et al., 2003). It is speculated that individuals unable to do so maybe in a greater risk of developing LBP in the future (Ostwal and Wani, 2014;O'Sullivan and Beales, 2007). ...
Article
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Background: The abdominal muscles play an important respiratory and stabilization role, and in coordination with other muscles regulate the intra-abdominal pressure stabilizing the spine. The evaluation of postural trunk muscle function is critical in clinical assessments of patients with musculoskeletal pain and dysfunction. This study evaluates the relationship between intra-abdominal pressure measured as anorectal pressure with objective abdominal wall tension recorded by mechanical-pneumatic-electronic sensors. Methods: In a cross-sectional observational study, thirty-one asymptomatic participants (mean age = 26.77 ± 3.01 years) underwent testing to measure intra-abdominal pressure via anorectal manometry, along with abdominal wall tension measured by sensors attached to a trunk brace (DNS Brace). They were evaluated in five different standing postural-respiratory situations: resting breathing, Valsalva maneuver, Müller’s maneuver, instructed breathing, loaded breathing when holding a dumbbell. Findings: Strong correlations were demonstrated between anorectal manometry and DNS Brace measurements in all scenarios; and DNS Brace values significantly predicted intra-abdominal pressure values for all scenarios: resting breathing (r = 0.735, r2 = 0.541, p < 0.001), Valsalva maneuver (r = 0.836, r2 = 0.699, p < 0.001), Müller’s maneuver (r = 0.651, r2 = 0.423, p < 0.001), instructed breathing (r = 0.708, r2 = 0.501, p < 0.001), and loaded breathing (r = 0.921, r2 = 0.848, p < 0.001). Interpretation: Intra-abdominal pressure is strongly correlated with, and predicted by abdominal wall tension monitored above the inguinal ligament and in the area of superior trigonum lumbale. This study demonstrates that intra-abdominal pressure can be evaluated indirectly by monitoring the abdominal wall tension.
... It is well known that the intraabdominal pressure (IAP) shows very wide variations in certain physiological or pathological condition such as changing the position of standing in supine exercise, coughing, sneezing, Valsalva maneuver [1]. Thus, different studies in the literature, report abdominal pressure values between 16 mmHg, 20 mmHg in standing 25-30 mmHg during exercise to lift a weight of 5 kg and the highest values of 06 mmHg -171 mmHg was recorded during coughing, sneezing or jumping. ...
... It is known that intra-abdominal pressure is maintained to normal or even slightly increased, even there are abdominal or parietal factors witch act positively. This is due to the degree of elasticity of the abdominal muscle wall which are able to take on some of the positive charges until reaching a critical point (usually IAP >15 mmHg) after, the intra-abdominal pressure increases suddenly [1]. Thus the degree of myorelaxation corresponding TOF ratio<2 was not enough to significantly alter the intra-abdominal pressure, exceeding this threshold instead led to sudden increases in intra-abdominal pressure in all analyzed. ...
Article
Aim: The purpose of the study is to verify the hypothesis that there is a correlation between the degrees of myorelaxation obtained by neuromuscular blockage during general anesthesia with changes in IAP values. Material and methods: The present study was carried out in surgery department, during September 2016 - October 2016. The plot consisted of 9 patients who undergone surgeries in the extra-abdominal area: 2 total thyroidectomies, 3 subtotal thyroidectomies, 3 simple mastectomy and one axilo-femoral bypass. Results: By comparing the results obtained in the nine cases, it was observed a statistically insignificant increase of intraabdominal pressure at train of four ratio values of 0, 1 or 2, intraabdominal pressure instead showed statistically significant variations in train of four ratio values of 3 or 4, observed especially at the reversal of anesthesia and patient waking up. Conclusions: Train of four ratio is an accurate indicator of the degree of neuromuscular blockage. Train of four ratio values of 0-2 changed statistically insignificant the intra-abdominal pressure. Increase train of four ratio over 3 led to sudden increases in intra-abdominal pressure.
... It has been suggested that extension torque is caused by the pressure acting on the diaphragm and pelvic floor (i.e., IAP production) (McGill et al. 1990;Stokes et al. 2010). Furthermore, IAP is considered as an important factor for enhancing the stability and stiffness of the spine and generating force/torque of limb muscles during kinetic chain activities involving trunk and hip extension such as lifting (Kawabata et al. 2010). Considering these aspects, it is reasonable to assume that high IAP is a factor for achieving high maximal voluntary hip extension torque. ...
... First, we did not control breathing of the subjects during the MVCs. It is known that force (Ikeda et al. 2009) as well as IAP (Hagins et al. 2006;Kawabata et al. 2010;McGill et al. 1990) during a given task is influenced by breathing state. Thus, there is a possibility that the observed association between IAP and MVC hip extension torque might involve the influence of breathing state. ...
Article
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Purpose: Muscle size of the hamstring and gluteus maximus (GM) as well as intra-abdominal pressure (IAP) are considered as factors affecting the torque development during hip extension. This study examined the associations of torque development during maximal voluntary isometric hip extension with IAP and muscle size of the hamstring and GM. Methods: Anatomical cross-sectional area (ACSA) of the hamstring and thickness of GM were determined in 20 healthy young males using an ultrasonography apparatus (Experiment 1). Torque and IAP were simultaneously measured while subjects performed maximal voluntary isometric hip extension. The IAP was measured using a pressure transducer placed in the rectum and determined at the time at which the developed torque reached to the maximal. In Experiment 2, torque and IAP were measured during maximal voluntary isometric hip flexion in 18 healthy young males. Results: The maximal hip extension torque was significantly correlated with the IAP (r = 0.504, P = 0.024), not with the ACSA of the hamstring (r = 0.307, P = 0.188) or the thickness of GM (r = 0.405, P = 0.076). The relationship was still significant even when the ACSA of the hamstring and the thickness of GM were adjusted statistically (r = 0.486, P = 0.041). The maximal hip flexion torque was not significantly correlated with the IAP (r = -0.118, P = 0.642). Conclusion: The current results suggest that IAP can contribute independently of the muscle size of the agonists to maximal voluntary hip extension torque.
... The most notable observation of the use of IAP to control force production is the Valsalva manoeuvre. This is commonly employed by athletes to increase lumbar stability and force production by increasing IAP during resistance exercises (Hagins, Pietrek, Sheikhzadeh, & Nordin, 2006;Kawabata, Shima, Hamada, Nakamura, & Nishizono, 2010;Tayashiki et al., 2018). The Valsalva manoeuvre involves a forced exhalation against a closed glottis to pressurise the trunk and intra-abdominal cavity (Hackett & Chow, 2013). ...
... There are a small number of studies that have attempted to determine the effect of other systems of martial arts training on the control of IAP. Kawabata et al. (2010) compared maximal isometric trunk flexor strength and IAP during isometric lifting tasks and found that trained judo practitioners had higher maximum IAP and stronger trunk flexor muscles than untrained controls. IAP was measured with an intra-rectal pressure transducer. ...
Thesis
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Introduction: The extent to which martial arts practitioners utilise respiratory pressures and neuromuscular activation during force production is not well known. This study investigated whether Chinese wushu (kung fu) practitioners utilise a greater proportion of intra-abdominal pressure (IAP) and neuromuscular activation of the respiratory and pelvic floor muscles to increase their force production compared to healthy control participants. Methods: Nine trained wushu practitioners and nine healthy untrained control participants were instrumented with skin-surface electromyography (EMG) electrodes on the sternocleidomastoid (EMGscm), rectus abdominis (EMGra) and the group formed by the transverse abdominal and internal oblique muscles (EMGtra/io). A multipair oesophageal EMG electrode catheter measured EMG of the crural diaphragm (EMGdi) along with gastric (Pg: a surrogate measure of IAP), transdiaphragmatic (Pdi), and oesophageal (Pe) pressures. Participants performed two tasks to measure force production: Standing Isometric Push and Standing Isometric Resistance. Participants were familiarised with the tasks and performed a minimum of three efforts for each task. Within-day, between-trial reproducibility intraclass correlation coefficients (ICC) for pressure, force and EMG were > 0.67 for trained and > 0.53 for control participants in the Standing Isometric Push task. ICC were also > 0.86 for trained and > 0.71 for control participants in the Standing Isometric Resistance task. Results: Compared to the control group, the trained group produced higher levels of force, lower Pe, and higher Pdi in both tasks (P < 0.05). The trained group produced higher Pg and higher EMGtra/io in the Standing Isometric Push task, and higher EMGdi in the Standing Isometric Resistance task (P < 0.05). The trained group had an earlier onset of Pg with respect to the onset of force production than the control group (P < 0.05). The relative contribution of Pg/Pe and Pdi/Pe were higher for the trained group (P < 0.05). Significant positive correlations were found between Pg and absolute force production in both groups (P < 0.05). Conclusions: Trained wushu practitioners appear to utilise IAP to a greater extent than untrained controls with similar physical activity levels to produce higher levels of force. These findings may have implications in a wide range of sports and activities, as these methods may be adapted and taught to individuals to improve performance, prevent injury or aid in rehabilitation.
... We suggest that in the case of PUE, this increased hydrostatic transmural pressure is caused by increased systemic blood pressure resulting from amplified abdominal muscle contractions. Changes in thoracic and intra-abdominal pressure caused by muscle contractions have been previously documented in humans (Kawabata et al., 2010) and cetaceans (Slijper, 1962;Lillie et al., 2017). Additionally, effects of the mammalian dive response (Scholander, 1940;Davis and Williams, 2012) and stress related peripheral vasoconstriction and tachycardia (Bonanno, 2011) may contribute to detrimental systemic blood pressure, but the effects are not well-understood and there may be compensatory mechanisms. ...
... The bulging of the rectus abdominis muscle during agonal PUE may further accentuate weak points within the rectus sheath, such as the site of emissary vessels. The increased abdominal pressure caused by the increased intensity/effort during isometric contractions (Harman et al., 1988;Hagins et al., 2004;Kawabata et al., 2010) provides additional opportunity for herniation. In humans, the inhalation form of breath control has been shown to produce greater intraabdominal pressure than other forms of breath hold (Hagins FIGURE 8 | Acute abdominal hernias in a bycaught bottlenose dolphin (with the peritoneum reflected back). ...
Article
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Peracute underwater entrapment (PUE) is a recognized cause of death associated with anthropogenic trauma in marine mammals. We describe internal lesions likely resulting from extreme agonal exertion in bottlenose dolphins due to entanglement and forced submergence in fishing gear during PUE. We reviewed necropsy findings from bottlenose dolphins with known PUE statuses in Virginia, United States from 2016–2019 (n = 31) for the presence of five lesions: pulmonary petechiae, pulmonary perivascular edema, hemorrhagic pulmonary lymph, separation of the rectus abdominis muscles, and acute abdominal hernias. Of the 31 cases, 23 were considered PUE cases due to the presence of external ligature marks consistent with entanglement in fishing gear. Of the animals examined, pulmonary perivascular edema, pulmonary petechiae, and hemorrhagic pulmonary lymph were found in both PUE and non-PUE cases. Though found in one non-PUE case, pulmonary perivascular edema was significantly related to PUE. There was no significant relationship between PUE and pulmonary petechiae or hemorrhagic pulmonary lymph. Rectus abdominis muscle separations and acute abdominal hernias were only found in PUE cases and nine animals exhibited either one (n = 7) or both (n = 2) of these traumatic lesions. Although these two lesions were relatively rare, there was a statistically significant relationship between the presence of one or both of the lesions and positive PUE status. This study suggests that pulmonary perivascular edema, acute hernias and separations of the rectus abdominis muscles may be useful for diagnosing PUE in the absence of external fishery interaction lesions, and highlights the severity of agonal fisheries interactions.
... A possible explanation for the aforementioned improvements of maximal hip extension torque and physical performance involving hip extension is a traininginduced change in intra-abdominal pressure (IAP). IAP has been suggested to play an important role for stabilization of core and force generation during movement involving lower limb such as lifting (Essendrop et al. 2004;Harman et al. 1988;Kawabata et al. 2010;McGill et al. 1990). Nevertheless, Hagins et al. (2006) reported that when comparing IAP and force during lifting task between two breath-hold conditions (i.e., inspiratory and expiratory states), IAP was greater in inspiratory condition than in expiratory condition, whereas no significant difference was observed in maximal lifting force (Hagins et al. 2006). ...
... The diaphragm contraction intensity is proportional to the lung volume (i.e., depth of inspiration) (Depalo et al. 2004;Hodges et al. 2001) and plays a significant role in producing high IAP. Indeed, IAP has been shown to vary with breathing state and lung volume (Hagins et al. 2004;Kawabata et al. 2010;McGill et al. 1990;Miyamoto et al. 1999). Therefore, to test the aforementioned hypothesis, we investigated IAP and torque during hip extension and flexion MVC tasks in three different breath-hold conditions. ...
Article
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Purpose: Intra-abdominal pressure (IAP) has been recently shown to be associated specifically with maximal voluntary isometric contraction (MVC) torque of hip extension, although the causal relationship remains unclear. The present study aimed to elucidate whether IAP has a causal effect on hip extension MVC torque. Methods: IAP during hip extension MVC was changed by controlling the lung volume (i.e., depth of inspiration). Twelve healthy males conducted MVCs of hip extension during breath-hold at full inspiration (inspiratory condition) or expiration (expiratory condition), or during normal breath-hold (normal condition). IAP during MVCs was measured a pressure transducer placed in the rectum. Results: The IAP during hip extension MVC was significantly higher in inspiratory condition (132.0 ± 46.1 mmHg) than in the other two conditions and also higher in normal condition (104.6 ± 35.9 mmHg) than in expiratory condition (77.0 ± 39.1 mmHg). The hip extension MVC torque was significantly higher in inspiratory condition (297.7 ± 82.7 N m) than in expiratory condition (266.4 ± 84.5 N m). In each condition, the hip extension MVC torque correlated with IAP during the MVC task. Conclusion: The current results suggest that IAP has a positive causal effect on hip extension MVC torque and that a sufficient increase in IAP directly leads to an enhancement of hip extension MVC torque.
... Although it has not been widely studied in aerobic performance [Verges et al. 2007;HajGhanbari et al. 2012], optimizing the respiratory function can play a crucial role in combat sports such as wrestling and judo, not only for its role in regulating the acid-base balance, but also in helping to distribute energy to all muscle groups [Tocilj, Erceg, Karnincic 2015]. Moreover, the intra-abdominal pressure and the strength of the respiratory muscles are closely related to the behavior of breathing during the Valsalva maneuver associated with weightlifting in highly trained judo athletes, including a coupling between respiratory muscle and peripheral force production [Kawabata et al. 2010]. Therefore, the respiratory muscles could play a critical role in judo performance because of their major involvement in posture [Cavaggioni et al. 2015; Barbado et al. 2016;Tukel et al. 2017]. ...
... Several limitations of the present study should be acknowledged. Firstly, the inspiratory muscle strength measurements were taken using volitional, non-invasive techniques, which are better tolerated by participants than the use of balloon catheter systems [Taylor, How, Romer 2006;Kawabata et al. 2010]. Although other techniques such as magnetic stimulation and balloon catheters provide more detailed information on respiratory muscle function, maximal volitional maneuvers have been shown reliable and valid for the measurement of inspiratory muscle strength [Romer, Polkey 2008;McConnell, Griffiths 2010]. ...
Article
Background. Respiratory muscles may play an important role in combat sports such as judo in order to meet the high ventilatory demand and to contribute to postural control. Problem and aim. To determine the influence of inspiratory muscle exercise (IMW) as specific respiratory muscle warm-up in a randomized controlled cross-over trial. Methods. 11 judo athletes were assigned to three different warm-up protocols and the effects of IMW on Special Judo Fitness Test (SJFT) were assessed. Each judoka completed three different IMW protocols: uchi-komi warm up (control); warm-up plus IMW (2 sets of 15 breaths with a 60% maximum inspiratory mouth pressure load); uchi-komi warm-up plus sham IMW warm-up (2 sets of 15 breaths with a 15% maximum inspiratory mouth pressure load). The SJFT performance was assessed following each type of warm-up protocol as well as heart rate (HR) and the rate of perceived exertion (RPE). Results. There was no effect of the warm-up protocol on total number of throws (p = 0.141), HR after the test (p = 0.676), HR 1 min after the test (p = 0.543) and performance index (p = 0.240) of the SJFT. However, RPE differed between conditions (p = 0.037), post-hoc Bonferroni tests indicating only a tendency for higher values in the high load IMW condition compared to the control (p = 0.061) and placebo (p = 0.095) conditions. Conclusion. High load IMW did not improve SJFT performance in elite judokas.
... Though a transducer may have excellent reliability on bench testing, many factors may cause variation in IAP measured in women doing l different activities in succession', such as displacement, signal density, awkward or unfamiliar tasks, body position, different degrees of effort, or different techniques used to accomplish a task. (7)(8)(9)(10). ...
Article
In the urodynamics laboratory setting, a wireless pressure transducer, developed to facilitate research exploring intra-abdominal pressure (IAP) and pelvic floor disorders, was highly accurate. We aimed to study reproducibility of IAP measured using this transducer in women during activities performed in an exercise science laboratory. Fifty-seven women (mean ± SD, age 30.4 ±9.3 years; body mass index, 22.4 ± 2.68 kg/m) completed 2 standardized activity sessions using the same transducer at least 3 days apart. Pressure data for 31 activities were transmitted wirelessly to a base station and analyzed for mean net maximal IAP, area under the curve, and first moment of the area. Activities included typical exercises, lifting 13.6 to 18.2 kg, and simulated household tasks. Analysis for test-retest reliability included Bland-Altman plots with absolute limits of agreement, Wilcoxon signed rank tests to assess significant differences between sessions, intraclass correlations, and κ statistics to assess intersession agreement in highest versus other quintiles of maximal IAP. Few activities exhibited significant differences between sessions in maximal IAP, or in area under the curve and first moment of the area values. For 13 activities, the agreement between repeat measures of maximal IAP was better than ±10 cm H20; for 20 activities, better than ±15 cm H20. The absolute limits of agreement increased with mean IAP. The highest quintile of IAP demonstrated fair/substantial agreement between sessions in 25 of 30 activities. Reproducibility of IAP depends on the activity undertaken. Interventions geared toward lowering IAP should account for this, maximize efforts to improve IAP reproducibility.
... Along with pelvic tilt, pelvic or lumbar stiffness can be significant factors in forward flexion ROM (31). Pelvic stiffness can be affected by intra-abdominal pressure (IAP) and trunk muscle activity, factors that are directly modified by breathing condition (16,29). Intra-abdominal pressure is the highest with full inhalations (11) and correlated with diaphragmatic activity (7,11). ...
Article
Two protocols were undertaken to help clarify the effects of breathing techniques on hamstrings (hip flexion) range of motion (ROM). The protocols examined effects of breathing conditions on ROM and trunk muscle activity. Protocol 1: Thirty recreationally active participants (15 male, 15 female, 20-25 years) were monitored for changes in single-leg raise (SLR) ROM with 7 breathing conditions prior to or during a passive supine SLR stretch. Breathing conditions included pre-stretch inhale, pre-stretch exhale, inhale during stretch, exhale during stretch, neutral, hyperventilation and hypoventilation prior to stretch. Protocol 2: Eighteen recreationally active participants (9 male, 9 female, 20-25 years) were monitored for electromyographic (EMG) activity of the rectus abdominus, external obliques, lower abdominal stabilizers, and lower erector spinae while performing the 7 breathing conditions prior to or during a passive SLR stretch. Control exhibited less ROM (p=0.008) than the pre-stretch inhale (7.7%), inhale during stretch (10.9%) and hypoventilation (11.2%) conditions with females. Protocol 2: Greater overall muscle activity in the pre-stretch exhale condition was found compared to inhale-during stretch (43.1%↓; p=0.029) and hypoventilation (51.2%↓; p=0.049) conditions. As the inhale during stretch and hypoventilation conditions produced the lowest levels of muscle activity for both sexes, as well as the highest ROM for the females, it can be assumed that both mechanical and neural factors affect female SLR ROM. Lesser male ROM might be attributed to anatomical differences such as greater joint stiffness. The breathing techniques may have affected intra-abdominal pressure, trunk muscle co-contractions and sympathetic neural activity to enhance female ROM.
... It has been considered that the reproducibility of indirect IAP measurements is influenced by not only body position but also respiratory artifacts in vivo [17]. Kawabata et al. [14] reported that the magnitude of the increase of IAP with increasing lifting effort was affected by the change in respiratory volume. In the current study, therefore, the subjects were asked to stop breathing at the end of resting expiration at the start of and during the IAP measurements in order to avoid any irregularities in breathing during the IAP measurements. ...
Article
This study examined the difference in intra-abdominal pressure (IAP) between abdominal bracing and hollowing in relation to trunk muscular activities. IAP with a pressure transducer placed in the rectum and surface electromyograms for rectus abdominis, external oblique, internal oblique, and erector spinae during the 2 tasks were obtained in 7 young adult men. The difference between IAP at rest and its peak value (ΔIAPmax) showed high intra- and inter-day repeatability, and was significantly greater in abdominal bracing (116.4±15.0 mmHg) than in abdominal hollowing (9.9±4.5 mmHg). The trunk muscular activities at ΔIAPmax were significantly higher in abdominal bracing than in abdominal hollowing, and in the internal oblique than in the other 3 muscles. In both abdominal bracing and hollowing, the changes in IAP during the tasks were linearly correlated with those in trunk muscular activities, but the slope of the regression line for the relationship differed between the 2 tasks. The current results indicate that 1) abdominal bracing is an effective maneuver to elevate IAP compared with abdominal hollowing, and 2) in the 2 tasks, the changes in IAP are linked with those in trunk muscular activities, but the association is task-specific. © Georg Thieme Verlag KG Stuttgart · New York.
... For example, weightlifting (isotonic resistance training) is associated with an intense and forceful breathing pattern often referred to as the Valsalva maneuver. This breathing pattern includes several phases, beginning with a forceful inhalation followed by a brief pause during which the glottis may be tightly sealed to prevent air leakage, and then a forceful exhalation through an open glottis (Ikeda et al. 2009;Kawabata et al. 2010;Talasz et al. 2011). Hence, presumably forceful breathing (i.e., Valsalva maneuver) requires rapid adjustments of the airway during forceful inhalation and exhalation as well as brief, relatively high supralaryngeal muscle forces assisting with the glottal closure to withstand the high subglottal air pressures. ...
Article
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Exercise mode (i.e., resistance training, endurance training) is known to yield mode‐specific effects on strength and endurance of muscles that are directly targeted during the exercise. Such mode‐specific effects can also be observed in indirectly involved (i.e., nontargeted) muscles. Mode‐specific muscle performance changes of nontargeted muscles, however, have only been investigated within the skeletal system. Therefore, as a first step, this study aimed to determine if bulbar muscle performance (tongue strength [TS], tongue endurance [TE]) differs between weightlifters and runners and if group differences are tongue region‐specific. The Iowa Oral Performance Instrument (IOPI) was used to measure TS and TE of the anterior and posterior tongue regions in 21 weightlifters and 23 runners. In weightlifters anterior TS was significantly greater than posterior TS (P = 0.008), whereas in runners anterior and posterior TS were comparable. Furthermore, weightlifters produced significantly greater anterior TS than runners (P = 0.001). Finally, TE was overall significantly greater in runners than in weightlifters (P = 0.001). Findings suggest that exercise mode may differentially impact performance patterns of nontargeted bulbar muscles. More research is warranted to better understand the mechanisms underlying tongue muscle performance differences between weightlifters and runners. This study aimed to determine if bulbar muscle performance (tongue strength, tongue endurance) differs between weightlifters and runners and if group differences are tongue region‐specific. The findings suggest that exercise mode may differentially impact performance patterns of nontargeted bulbar muscles. More research is warranted to better understand the mechanisms underlying tongue muscle performance differences between weightlifters and runners.
... [1] Kawabata et al. measured the increase in intra-abdominal pressure during voluntary Valsalva in 10 highly trained male judo athletes and 11 healthy men, who performed standardized isometric lifting efforts. [2] The study showed that there was an increase in the maximal intra-abdominal pressure during Valsalva up to a mean of 204 ± 50 mmHg in trained male athletes and 140 ± 37 mmHg in healthy men, measured in standing position using intrarectal transducer. [3] Cobb et al. measured maximum intra-abdominal pressure at 64 mmHg (mean -39.7 mmHg, minimum -20 mmHg, and SD -11 mmHg) in healthy volunteers during Valsalva maneuver at rest, in supine position. ...
Article
A 54-year-old male presented to the outpatient surgery clinic with chronic intermittent right inguinal pain. An unenhanced computed tomography (CT) scan during Valsalve maneuver was performed, which demonstrated aortoiliac narrowing. Kinking of the duodenum and renal vasculature, and flattening of the inferior vena cava and iliac vasculature were also noted. A CT angiogram was subsequently performed without Valsalva maneuver which demonstrated complete resolution of the vascular and enteric findings. The case demonstrates that transient aortoiliac narrowing can also occur during voluntary Valsalva maneuver. Awareness of this entity is important so that patients can be reassured about the transient physiologic nature of these findings.
... The pressure transducer was fi tted with a rubber probe cover (P249, Nikkiso-YSI Co., Ltd., Musashino, Japan) to prevent contamination. In line with a prior study, the probe cover was pierced with small holes in several places to prevent any trapped air from acting as a pressure buff er [ 13 ] . The transducer and the connector linking the transducer and pressure sensor were waterproofed using waterproof plastic and tape in order to prevent the danger of electrical leakage. ...
Article
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The present study aimed to determine the intra-abdominal pressure during front crawl swimming at different velocities in competitive swimmers and to clarify the relationships between stroke indices and changes in intra-abdominal pressure. The subjects were 7 highly trained competitive collegiate male swimmers. Intra-abdominal pressure was measured during front crawl swimming at 1.0, 1.2 and 1.4 m · s-1 and during the Valsalva maneuver. Intra-abdominal pressure was taken as the difference between minimum and maximum values, and the mean of 6 stable front crawl stroke cycles was used. Stroke rate and stroke length were also measured as stroke indices. There were significant differences in stroke rate among all velocities (P<0.05). However, there was no significant difference in stroke length by velocity. Significant within-subject correlations between intra-abdominal pressure and stroke rate or stroke length (P<0.01) were observed, although there were no significant correlations between intra-abdominal pressure and stroke indices when controlling for swimming velocity. These findings do not appear to support the effectiveness of trunk training performed by competitive swimmers aimed at increasing intra-abdominal pressure.
... Physical therapists focused on changes in the transverses abdominis muscle (TrA) thickness and showed that training of the TrA, which is rarely activated on a daily base, utilizing breathing with abdominal pressure can achieve strengthening of TrA contraction [5]. Researchers of sports and urology had tried to study in various ways [6] [7] [8] [9] [10]. However, their physical approach did not refer to the mental effects of breathing. ...
... Various measurement procedures have been used to investigate the postural-respiratory function of the abdominal muscles and related IAP changes. Esohpageal, gastric [20], intravesical [21], anal [22,23], and vaginal [24] probes can measure IAP, yet these methods are often time consuming and uncomfortable for patients. Electromyography [23] and ultrasound [25] assessments have also been used to analyze activity of the abdominal muscles, but these methods can be burdensome, technically demanding to perform while the former poses serious difficulty regarding its reproducibility and hence interpretation. ...
Article
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BACKGROUND: The abdominal muscles play an important respiratory and stabilization role, and in coordination with other muscles regulate intra-abdominal pressure (IAP) to stabilize the spine. OBJECTIVE: To examine a new, non-invasive method to measure activation of the abdominal wall and compare changes in muscle activation during respiration while breathing under a load, and during instructed breathing. METHODS: Thirty-five healthy individuals completed this observational crossover study. Two capacitive force sensors registered the abdominal wall force during resting breathing stereotype, instructed breathing stereotype and under a load. RESULTS: Mean abdominal wall force increased significantly on both sensors when holding the load compared to resting breathing (Upper Sensor: P< 0.0005, d=-0.46, Lower Sensor: P< 0.0005, d=-0.56). The pressure on both sensors also significantly increased during instructed breathing compared to resting breathing (US: P< 0.0005, d=-0.76, LS: P< 0.0005, d=-0.78). CONCLUSIONS: The use of capacitive force-sensors represent a new, non-invasive method to measure abdominal wall activity. Clinically, belts with capacitive force sensors can be used as a feedback tool to train abdominal wall activation.
... Putative mechanisms include improved technique, muscular strength and endurance as a result of physical training (James et al. 2017(James et al. , 2018Machado et al. 2010). In addition, the greater ability of trained martial arts practitioners to produce and resist forces to aid combat performance may also be due to enhanced neuromuscular activation and control of the respiratory, abdominal and pelvic floor musculature leading to higher intra-abdominal pressures (Essendrop et al. 2004;Kawabata et al. 2010). This may result from specialised forms of breath control training found in many traditional martial arts systems. ...
Article
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Purpose The mechanisms that explain the ability of trained martial arts practitioners to produce and resist greater forces than untrained individuals to aid combat performance are not fully understood. We investigated whether the greater ability of trained martial arts practitioners to produce and resist forces was associated with an enhanced control of respiratory pressures and neuromuscular activation of the respiratory, abdominal, and pelvic floor musculature. Methods Nine trained martial arts practitioners and nine untrained controls were instrumented with skin-surface electromyography (EMG) on the sternocleidomastoid, rectus abdominis, and the group formed by the transverse abdominal and internal oblique muscles (EMGtra/io). A multipair oesophageal EMG electrode catheter measured gastric (Pg), transdiaphragmatic (Pdi), and oesophageal (Pe) pressures and EMG of the crural diaphragm (EMGdi). Participants performed Standing Isometric Unilateral Chest Press (1) and Standing Posture Control (2) tasks. Results The trained group produced higher forces normalised to body mass2/3 (0.033 ± 0.01 vs. 0.025 ± 0.007 N/kg2/3 mean force in Task 1), lower Pe, and higher Pdi in both tasks. Additionally, they produced higher Pg (73 ± 42 vs. 49 ± 19 cmH2O mean Pg) and EMGtra/io in Task 1 and higher EMGdi in Task 2. The onset of Pg with respect to the onset of force production was earlier, and the relative contributions of Pg/Pe and Pdi/Pe were higher in the trained group in both tasks. Conclusion Our findings demonstrate that trained martial arts practitioners utilised a greater contribution of abdominal and diaphragm musculature to chest wall recruitment and higher Pdi to produce and resist higher forces.
... E. Intrarectal measurement Another method is performed via the rectum. Advantage of this method is that the patient can move and do some physical activities, while the IAP is measured (42). According to Dolan et al., 20% of women refuse to undergo this examination because of fear and they prefer intravaginal measuring (43). ...
Article
Intra-abdominal pressure is a hydraulic pressure within the abdominal cavity. Previous studies confirmed its direct association with both spinal stability and spinal unloading. The literature review part of the paper summarizes intra-abdominal pressure physiology and pathophysiology and explains the underlying mechanisms of Intra-abdominal pressure regulation and its effects on the human body, especially spinal stability. Current methods of invasive and non-invasive intra-abdominal pressure measurement are described in detail. Second part of a paper presents a case report of a competitive athlete suffering from low back pain. The functional assessment and treatment focused on quality of patient’s trunk stabilization. Training following principles of Dynamic Neuromuscular Stabilization resulted in better ability to activate abdominal wall muscles which is a critical mechanism of Intra-abdominal pressure regulation and in this case caused significant low back pain reduction. The effect of the therapy was evaluated by DNS Brace which measures activity of the abdominal wall, thus Intra-abdominal pressure indirectly, along with clinical Dynamic Neuromuscular Stabilization assessment tests. https://doi.org/10.24040/sjss.2021.7.2.3-18
... However, maximum pressures during coughing and vomiting were 233 mm Hg and 290 mm Hg, enough to well exceed this patient's diastolic blood pressure [6] . In another study, both control and trained judo athletes were capable of exerting 140 mm Hg and 204 mm Hg of intra-abdominal pressure respectively during an isometric lifting effort [7] . ...
Article
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Computed tomography (CT) being performed with Valsalva is an efficacious and common technique performed to evaluate for abdominal hernias. In certain circumstances, Valsalva can generate sufficient intra-abdominal pressure to cause aortoiliac compression that can raise concerns for possible aortic atresia. Repeat CT without Valsalva generally demonstrates that these changes are transitory, and no further intervention is typically required. Given the ever-growing number of CTs with Valsalva being performed for hernia evaluation, clinicians involved in interpreting abdominal CTs should be aware of this concerning appearing but ultimately benign phenomenon.
... A gradual increase in intra-abdominal pressure has been found during sustained lifting, reaching levels around 20 mmHg when the subjects were exhausted after around 8 minutes (64). Intra-abdominal pressures >100 mmHg have been measured during heavy lifting in a stooping position, especially during rapid lifts (65), and intra-abdominal pressures around 120 mmHg have been measured during lifting for a few seconds using maximal force (66). Sudden trunk loading during simulated patient handling situations where the patient fell resulted in peak intra-abdominal pressures of 153 mmHg and 120 mmHg among well-trained men and women, respectively (67). ...
Article
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Objectives: The aim of this review was to evaluate the epidemiologic evidence for (i) a causal effect of occupational mechanical exposures on incidence of inguinal hernia, and (ii) a prognostic effect of such exposures on hernia recurrence and persistent pain after inguinal hernia repair. Methods: We performed a literature search in Medline, Embase, and Web of Science up to 3 November 2011. Central information was extracted from included studies, and strengths and limitations were discussed. Results: All 23 included studies focused on effects of (work) activities that hardly reflected specific occupational risk factors. Eight studies provided information on risk by occupation or occupational activities. Increased risk was reported in six studies, but inflationary bias was likely. The negative findings in two studies might well be explained by bias towards the null due to crude exposure and/or outcome assessment. Three studies on single strenuous events primarily reflected patients` beliefs regarding risk factors. Information on prognosis with respect to recurrence was found in seven studies. The studies used crude exposure assessment, and two were also underpowered. Four suggested an increased risk. Six studies on prognosis with respect to persistent pain (one of which also concerned recurrence) were practically non-informative for the purpose of this review. Conclusions: There is insufficient epidemiologic evidence to draw meaningful conclusions about (i) the existence of causal associations between specific occupational mechanical exposures and the development of inguinal hernia, and (ii) the influence of these exposures on prognosis after inguinal hernia repair with respect to hernia recurrence and persistent pain.
Article
Many surgeons recommend rest and restricting activities to their patients after surgery. The aim of this review is to summarize the literature regarding types of activities gynecologic surgeons restrict and intra-abdominal pressure during specific activities and to provide an overview of negative effects of sedentary behavior (rest). We searched PubMed and Scopus for years 1970 until present and excluded studies that described recovery of activities of daily living after surgery as well as those that assessed intra-abdominal pressure for other reasons such as abdominal compartment syndrome and hypertension. For our review of intra-abdominal pressure, we excluded studies that did not include a generally healthy population, or did not report maximal intra-abdominal pressures. We identified no randomized trial or prospective cohort study that studied the association between postoperative activity and surgical success after pelvic floor repair. The ranges of intra-abdominal pressures during specific activities are large and such pressures during activities commonly restricted and not restricted after surgery overlap considerably. There is little concordance in mean peak intra-abdominal pressures across studies. Intra-abdominal pressure depends on many factors, but not least the manner in which it is measured and reported. Given trends towards shorter hospital stays and off work intervals, which both predispose women to higher levels of physical activity, we urge research efforts towards understanding the role of physical activity on recurrence of pelvic organ prolapse and urinary incontinence after surgery.
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We aimed to examine the association between several breathing patterns and postures on abdominal muscle activation and intra-abdominal pressure (IAP). Fourteen healthy men performed four active breathing tasks: quiet nasal breathing (Q-Bre), nasal diaphragmatic breathing (Dia-Bre), completely forced expiration (Forced-Expi), and exertional nasal inhalation with abdominal muscles in isometric contraction (Exertion-Inspi) in the elbow-toe and supine posture. Breathing volume, IAP, and transverse abdominis-internal oblique muscle (TrA-IO) and external oblique muscle (EO) activity were recorded. Abdominal muscle activity and IAP were significantly associated with breathing pattern and postures during the expiratory phase. In the inspiratory phase, TrA-IO activity were significantly associated with breathing pattern and EO activity with posture. TrA-IO activity significantly increased in Forced-Expi in the supine posture (47.6% of the maximum voluntary contraction) and Exertion-Inspi in the elbow-toe posture (35.7%), while no differences were found for Dia-Bre or Q-Bre (<20%). EO activity increased in the elbow-toe posture (22.5–30.6%) compared with that in the supine posture (<5%) for all breathing tasks. IAP values were low for all tasks (<15%) except Forced-Expi (24.9%). Breathing pattern, including posture, is a crucial element for determining abdominal muscle activity in exercise instruction.
Article
A brief Valsalva manoeuvre, lasting 2-3 s, performed by young healthy men during strength exercise reduces transmural pressure acting on intrathoracic arteries. In this study, we sought to verify this finding in older men. Twenty normotensive, prehypertensive and moderately hypertensive otherwise healthy men 46-69 years old performed knee extensions combined with inspiration or with brief Valsalva manoeuvre performed at 10, 20 and 40 mmHg mouth pressure. Same respiratory manoeuvres were also performed at rest. Non-invasively measured blood pressure, knee angle, respiratory airflow and mouth pressure were continuously registered. In comparison to inspiration, estimated transmural pressure acting on thoracic arteries changed slightly and insignificantly during brief Valsalva manoeuvre at 10 and 20 mmHg mouth pressure. At 40 mmHg mouth pressure, transmural pressure declined at rest (-8·8 ± 11·4 mmHg) and during knee extension (-12·1 ± 11·9 mmHg). This decline ensued, as peak systolic pressure increase caused by this manoeuvre, was distinctly <40 mmHg. Only a main effect of mouth pressure was revealed (P<0·001) and neither exercise nor interaction between these factors, what suggests that transmural pressure decline, depended mainly on intrathoracic pressure developed during brief Valsalva manoeuvre. Resting blood pressure did not influence the effect of brief Valsalva manoeuvre on transmural pressure.
Article
Purpose Intra-abdominal pressure (IAP) and breathing behaviour are important preparative pre-lifting actions for functional stability during lifting. This study aimed to examine spontaneous changes in the peak rate of IAP development (Rate-IAP), peak IAP (Peak-IAP), the time of Rate- and Peak-IAP occurrence and respiratory volume in response to dynamic load lifting. Methods Eleven healthy men performed quick dynamic deadlifting using 30, 45, 60 and 75 % of the isometric maximal lifting effort (iMLE). IAP was measured using an intrarectal pressure transducer. The spontaneous respiratory volume was calculated from air flow data using pneumotachography. The lifting motion onset was determined from the hip joint motion using an electrogoniometer. Results From 30 to 75 % of the iMLE, Rate-IAP occurred early from 2 ± 28 to −179 ± 16 ms (P
Article
Pelvic floor disorders affect 24% of US women, and elevated intra-abdominal pressure may cause pelvic injury through musculoskeletal strain. Activity restrictions meant to reduce pelvic strain after traumatic events, such as childbirth, have shown little benefit to patients. Reported high variability in abdominal pressure suggests that technique plays a substantial role in pressure generation. Understanding these techniques could inform evidence-based recommendations for protective pelvic care. We hypothesized use of a motion-capture methodology could identify four major contributors to elevated pressure: gravity, acceleration, abdominal muscle contraction, and respiration. Twelve women completed nineteen activities while instrumented for whole body motion capture, abdominal pressure, hip acceleration, and respiration volume. Correlation and partial least squares regression were utilized to determine primary technique factors that increase abdominal pressure. The partial least squares model identified two principal components that explained 59.63% of relative intra-abdominal pressure variability. The first component was primarily loaded by hip acceleration and relative respiration volume, and the second component was primarily loaded by flexion moments of the abdomen and thorax. While reducing abdominal muscle use has been a primary strategy in protective pelvic floor care, the influence of hip acceleration and breathing patterns should be considered with similar importance in future work.
Article
Case control, repeated-measures, experimental laboratory study. To determine if, during a whole-body lifting task, individuals with low back pain (LBP) breathe differently than age-matched controls. Breath control may be optimized to provide increased intersegmental control of the lumbar spine through the generation of intra-abdominal pressure. Consequently, impairments in respiratory and trunk muscle coordination during lifting tasks may contribute to the occurrence or maintenance of LBP. Participants without LBP (n = 30) were matched by gender and age with those presenting with chronic mechanical LBP (n = 32) of at least 1 year in duration. Participants completed a total of 8 self-paced lifts of a crate from the floor to a table, with the crate empty during 4 of the lifts and loaded to 25% of the participant's body weight during 4 of the lifts. The amount of volume in the lungs, measured as a percentage of the individual's vital capacity (%VC), was identified at 9 points during the lifting task. A 2 × 2 × 2 × 9 (group by gender by load by time) mixed-model analysis of covariance (ANCOVA), with age as the covariate, was used to identify differences among conditions and groups of %VC used during the lift. Individuals with LBP performed the lifting task with more volume in their lungs (48.2 %VC) than healthy peers (40.9 %VC). Age significantly affected %VC used during the lift: with increasing age, participants with LBP increased inspired volume and participants without LBP decreased inspired volume. Individuals with LBP performed a lifting task with more inhaled lung volume than individuals without LBP. These findings are consistent with the theoretical link between breath control, intra-abdominal pressure, and lumbar segmental control.
Article
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Unexpected ventral and dorsal perturbations and expected, self-induced ventral perturbations were delivered to the trunk by suddenly loading a vest strapped to the torso. Six male subjects were measured for intra-abdominal pressure (IAP) and intra-muscular electromyography of the transversus abdominis (TrA), obliquus internus abdominis (OI), obliquus externus abdominis (OE) and rectus abdominis (RA) muscles. Erector spinae (ES) activity was recorded using surface electromyography. Displacements of the trunk and head were registered using a video-based system. Unexpected ventral loading produced activity in TrA, OI, OE and RA, and an IAP increase well in advance of activity from ES. Expected ventral loading produced pre-activation of all muscles and an increased IAP prior to the perturbation. The TrA was always the first muscle active in both the unexpected and self-loading conditions. Of the two ventral loading conditions, forward displacement of the trunk was significantly reduced during the self-loading. Unexpected dorsal loading produced coincident activation of TrA, OI, OE, RA and ES. These results indicate a response of the trunk muscles to sudden expected and unexpected ventral loadings other than the anticipated immediate extensor torque production through ES activation. It is suggested that the increase in IAP is a mechanism designed to improve the stability of the trunk through a stiffening of the whole segment.
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The increased intra-abdominal pressure (IAP) commonly observed when the spine is loaded during physical activities is hypothesized to increase lumbar spine stability. The mechanical stability of the lumbar spine is an important consideration in low back injury prevention and rehabilitation strategies. This study examined the effects of raised IAP and an abdominal belt on lumbar spine stability. Two hypotheses were tested: (1) An increase in IAP leads to increased lumbar spine stability, (2) Wearing an abdominal belt increases spine stability. Ten volunteers were placed in a semi-seated position in a jig that restricted hip motion leaving the upper torso free to move in any direction. The determination of lumbar spine stability was accomplished by measuring the instantaneous trunk stiffness in response to a sudden load release. The quick release method was applied in isometric trunk flexion, extension, and lateral bending. Activity of 12 major trunk muscles was monitored with electromyography and the IAP was measured with an intra-gastric pressure transducer. A two-factor repeated measures design was used (P < 0.05), in which the spine stability was evaluated under combinations of the following two factors: belt or no belt and three levels of IAP (0, 40, and 80% of maximum). The belt and raised IAP increased trunk stiffness in all directions, but the results in extension lacked statistical significance. In flexion, trunk stiffness increased by 21% and 42% due to 40% and 80% IAP levels respectively; in lateral bending, trunk stiffness increased by 16% and 30%. The belt added between 9% and 57% to the trunk stiffness depending on the IAP level and the direction of exertion. In all three directions, the EMG activity of all 12 trunk muscles increased significantly due to the elevated IAP. The belt had no effect on the activity of any of the muscles with the exception of the thoracic erector spinae in extension and the lumbar erector spinae in flexion, whose activities decreased. The results indicate that both wearing an abdominal belt and raised IAP can each independently, or in combination, increase lumbar spine stability. However, the benefits of the belt must be interpreted with caution in the context of the decreased activation of a few trunk extensor muscles.
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This study investigated the effect of inspiratory muscle strength training (IMST) on inspiratory motor drive [mouth occlusion pressure at 0.1 s (P(0.1))] and respiratory-related evoked potentials (RREP). It was hypothesized that, if IMST increased inspiratory muscle strength, inspiratory motor drive would decrease. If motor drive were related to the RREP, it was further hypothesized that an IMST-related decrease in drive would change RREP latency and/or amplitude. Twenty-three subjects received IMST at 75% of their maximal inspiratory pressure (Pi(max)) with the use of a pressure threshold valve. IMST consisted of four sets of six breaths daily for 4 wk. P(0.1) and the RREP were recorded before and after IMST. Posttraining, Pi(max) increased significantly by 36.0 +/- 2.7%. P(0.1) decreased significantly by 21.9 +/- 5.2%. The increase in Pi(max) was significantly correlated to the decrease in P(0.1). RREP peaks P(1a), N(f), P(1), and N(1) were identified pre- and post-IMST, and there was no difference in either amplitude or latency for those peaks. These results demonstrate that high-intensity IMST significantly increased Pi(max), decreased P(0.1), but did not change the RREP.
Article
This study examined changes in intra-abdominal pressure and trunk activation during drop jump and the influence of those factors on performance. Intra-abdominal pressure (IAP) and surface electromyography (EMG) activity from the rectus abdominis (RA), transversus abdominisinternal oblique (TrA-IO) and erector spinae (ES) muscles were measured in seven males (22.3±1.0 years) during double-leg drop jumps from a 0.4 m height. Development of IAP (ΔIAP) and normalized rmsEMGs were calculated in the pre-contact, impact and push-off phases, after divided by ground reaction force data. TrA-IO activation which occurred prior to ground contact were the earliest and strongest compared to other muscles activation during each phase. ΔIAP during the impact phase coincided with the peak vertical force. There were significant positive correlations between ΔIAP, TrA-IO activation and vertical force per weight. In addition, the contact time correlated negatively with ΔIAP, TrA-IO activation and vertical force per weight. These findings indicate that ΔIAP and TrA-IO activation may contribute to trunk stability and efficient landing during double-leg drop jump.
Article
To evaluate the effects of abdominal belts on lifting performance, muscle activation, intra-abdominal pressure and intra-muscular pressure of the erector spinae muscles. Simultaneous measurement of intra-abdominal pressure, intra-muscular pressure of the erector spinae muscles was performed during the Valsalva maneuver and some isometric lift exertions. While several hypotheses have been suggested regarding the biomechanics of belts and performance has been found to increase when lifting with belts, very little is known about the modulating effects on trunk stiffness. At present, there is no reason to believe that spine tolerance to loads increases with belts. An abdominal belt designed for weightlifting was used. Intra-abdominal pressure, intra-muscular pressure of the erector spinae muscles and myoelectric activities of trunk muscles (erector spinae, rectus abdominis and external oblique) were measured simultaneously during the Valsalva maneuver as well as three types of isometric lifting exertions (arm, leg and torso lift). A paired t-test was used to analyze for statistical differences between the two conditions (without-belt and with-belt) in intra-abdominal pressure, intra-muscular pressure of the erector spinae muscles and in the integrated EMG of the trunk muscles. Intra-muscular pressure of the erector spinae muscles increased significantly by wearing the abdominal belt during Valsalva maneuvers and during maximum isometric lifting exertions, while maximum isometric lifting capacity and peak intra-abdominal pressure were not affected. Integrated EMG of rectus abdominis increased significantly by wearing the abdominal belt during Valsalva maneuvers (after full inspiration) and during isometric leg lifting. Wearing abdominal belts raises intra-muscular pressure of the erector spinae muscles and appears to stiffen the trunk. Assuming that increased intra-muscular pressure of the erector spinae muscles stabilizes the lumbar spine, wearing abdominal belts may contribute to the stabilization during lifting exertions.
Article
The aim was to investigate possible relationships between activities of the individual muscles of the ventrolateral abdominal wall and the development of pressure within the abdominal cavity. Intra-muscular activity was recorded bilaterally from transversus abdominis, obliquus internus, obliquus externus and rectus abdominis with fine-wire electrodes guided into place using real-time ultrasound. Intra-abdominal pressure was measured intragastrically using a micro tip pressure transducer. Six males were studied during loading and movement tasks with varied levels of intra-abdominal pressure. During both maximal voluntary isometric trunk flexion and extension, transversus abdominis activity and intra-abdominal pressure remained constant, while all other abdominal muscles showed a marked reduction during extension. When maximal isometric trunk flexor or extensor torques were imposed upon a maximal Valsalva manoeuvre, transversus abdominis activity and intra-abdominal pressure remained comparable within and across conditions, whereas obliquus internus, obliquus externus and rectus abdominis activities either markedly increased (flexion) or decreased (extension). Trunk twisting movements showed reciprocal patterns of activity between the left and right sides of transversus abdominis, indicating an ability for torque development. During trunk flexion--extension, transversus abdominis showed less distinguished changes of activity possibly relating to a general stabilizing function. In varied pulsed Valsalva manoeuvres, changes in peak intra-abdominal pressure were correlated with mean amplitude electromyograms of all abdominal muscles, excluding rectus abdominis. It is concluded that the co-ordinative patterns shown between the muscles of the ventrolateral abdominal wall are task specific based upon demands of movement, torque and stabilization. It appears that transversus abdominis is the abdominal muscle whose activity is most consistently related to changes in intra-abdominal pressure.
Article
The purpose of this study was to determine whether abdominal belts such as those prescribed to industrial workers reduced trunk muscle activity and/or increased intra-abdominal pressure (IAP). In this study, six subjects lifted loads (72.7 to 90.9 kg) both with and without wearing a weightlifter belt. In addition, further trial conditions required that subjects lifted both with the breath held or continuously expiring on lifting effort. Dynamic hand loads were recorded together with intra-abdominal pressure (IAP) and abdominal, intercostal and low back EMG. Every subject demonstrated an increase in IAP when wearing the belt during both breathing conditions: 99 mmHg with no belt; 120 mmHg wearing belt (p less than 0.0001). However, it was also found that significant increases in IAP occurred (p less than 0.017) when the breath was held versus exhaling with or without the belt. One would expect that if the belt relieved either the direct compressive load on the spine or assisted IAP to produce an extensor moment then this would be reflected in diminished extensor muscle activity. Erector spinae activity tended to be lower with the breath held suggesting a reduced load on the lumbar spine although wearing a belt did not augment this reduction. In the case studies with subjects wearing an ergogenic corset designed for use by industrial manual materials handlers, perceptions of improved trunk stability were reported. However, the muscle activity and IAP results of this study during short duration lifting tasks make it difficult to justify the prescription of abdominal belts to workers.
Article
The aim of this study was to compare trunk muscle strength and intra-abdominal pressure during lifting in low-back patients and in healthy controls. Twenty male workers with 2-18 year history (median 5.5 years) of low-back pain went through strength tests of trunk flexion and extension and a series of standardized lifts. The intra-abdominal pressure (IAP) and the EMG activity of the oblique abdominal muscles and of the erector spinae muscles were recorded. The results were compared with those in 20 healthy men exposed to similar loads at work and at leisure. The low-back patients had reduced abdominal muscle strength (-25%) compared with the healthy controls. The IAP during lifting was the same in the two groups despite the difference in abdominal muscle strength. The trunk extension strength was the same in the two groups. The oblique abdominal muscles were only moderately activated during lifting (5-15% of maximum activity with 25 kg) both in low-back patients and in healthy controls. The erector spinae muscle was strongly activated during lifting (40-60% of maximum activity with 25 kg) both in low-back patients and in healthy controls. During backlifting the duration of erector spinae activity varied. Back patients had extended activity compared with the healthy controls. Stiffness seemed to affect the duration of activity in both groups. The oblique abdominal muscles seem to be of no decisive importance to the IAP.
Article
The intra-abdominal pressure (IAP) has been regarded as important for stabilization and relief of the lumbar spine when exposed to heavy loads, such as when lifting. Previous trials, however, have failed to increase the IAP by abdominal muscle training. Twenty healthy subjects, 20 low-back patients and 10 weight-lifters, were tested with various breathing techniques in order to elucidate the causal factors of the IAP rise during lifting and the effects respiration. Those with high IAP and low IAP as well as those with great variations in IAP underwent an extended program. The intra-abdominal and intrathoracic pressures and the EMG of the oblique abdominal, the erector spinae and--in some cases--the puborectalis muscles, were recorded. The transdiaphragmatic pressure was calculated both during lifting and during the Mueller manoeuvre. The IAP rise during lifting seems to be correlated to a good coordination between the muscles surrounding the abdominal cavity. Of these, the diaphragm seems to be the most important for the IAP level. Closure of the glottis seems to help the diaphragm to maintain the IAP rise, otherwise the respiration type seems to be less important for the IAP during lifting.
Article
The aim of the work is to establish guidelines for force applications by all normal female workers which can be used to assess the acceptability of existing working conditions, and to assist in the design of new working procedures. A significant relationship between lumbar stress and increase in intra-abdominal pressure has been established for females which is sufficiently sound for use when investigating load handling by women in industry. Female occupations with differing incidences of posterior trunk injuries have been identified and it has been shown that the lumbar stresses sustained by the high- and low-risk groups are different. This difference has been used to create a provisional level of lumbar stress for female which, if exceeded sufficiently often, might increase the risk of a back injury. Force limits for a fit young female population based on this provisional level are, on average, between 45 and 60% of the corresponding male limit values. It is hoped to confirm these findings in the near future.
Article
Intra-abdominal pressures were measured simultaneously with a wireless radio pill and two wire-connected pressure transducers introduced orally and rectally respectively. Measurements were made on 8 men during common postures, simple activities and static and dynamic lifting. An acceptable correspondence was found in wave forms of the generated pressure curves in time and shape. The three systems showed, however, a less good agreement in recorded peak differences, i.e. highest and lowest pressure responses to each task. The radio pill is simple to use, but more difficult to calibrate and expensive, compared to the wire-connected methods, which however are less attractive for use in the work environment.
Article
A study of 12 women undergoing laparoscopy revealed that measurement of rectal pressure at a depth greater than 10 cm accurately reflects changes in intra-abdominal pressure. Measuring rectal pressure at a depth of less than 10 cm results in overestimation of intra-abdominal pressure changes. The diagnostic implications of this effect are discussed.
Article
Muscles of the torso have been implicated to play a role in stabilization of the low back, and to assist in ventilation. This motivated an investigation to combine a load challenge to the low back with a breathing challenge, similar to that which a worker might experience when shovelling snow. Perhaps modulation of muscle activity needed to facilitate breathing may compromise the margin of safety of tissues that depend on constant muscle activity for support. Eight young healthy males dynamically lifted, and isometrically held, large loads (73-95 kg) and breathed a 10% CO2 gas mixture to elevate breathing (both with and without hand-held loads). Individual tissue forces were calculated using an anatomically detailed, dynamic model of the torso that was sensitive to individual variation by utilizing myoelectric signals, intra-abdominal pressure, ventilation rate and spine kinematics, obtained from each subject, as input. For large loads in the hands, most subjects appeared to stabilize the trunk with large muscle forces relegating the responsibility of creating lung air flow to the diaphragm. When reasonably small low-back demands were coupled with a breathing challenge and higher ventilation rates two out of eight subjects demonstrated entrainment of abdominal activity to breathing that resulted in additional cyclic low-back compressive loading of the order of 1000 N. Ergonomists should consider the additional tissue loading from physiologically demanding tasks and the related ventilation challenge, together with the tissue loads required to support external objects and maintain body posture.
Intra-abdominal pressure (IAP), force and electromyographic (EMG) activity from the abdominal (intra-muscular) and trunk extensor (surface) muscles were measured in seven male subjects during maximal and sub-maximal sagittal lifting and lowering with straight arms and legs. An isokinetic dynamometer was used to provide five constant velocities (0.12-0.96 m.s-1) of lifting (pulling against the resistance of the motor) and lowering (resisting the downward pull of the motor). For the maximal efforts, position-specific lowering force was greater than lifting force at each respective velocity. In contrast, corresponding IAPs during lowering were less than those during lifting. Highest mean force occurred during slow lowering (1547 N at 0.24 m.s-1) while highest IAP occurred during the fastest lifts (17.8 kPa at 0.48-0.96 m.s-1). Among the abdominal muscles, the highest level of activity and the best correlation to variations in IAP (r = 0.970 over velocities) was demonstrated by the transversus abdominis muscle. At each velocity the EMG activity of the primary trunk and hip extensors was less during lowering (eccentric muscle action) than lifting (concentric muscle action) despite higher levels of force (r between -0.896 and -0.851). Sub-maximal efforts resulted in IAP increasing linearly with increasing lifting or lowering force (r = 0.918 and 0.882, respectively). However, at any given force IAP was less during lowering than lifting. This difference was negated if force and IAP were expressed relative to their respective lifting and lowering maxima.(ABSTRACT TRUNCATED AT 250 WORDS)
Article
When lifting heavy loads, trunk muscle contraction converts the abdominal and thoracic cavities into a nearly rigid-walled cylinder that provides increased extrinsic stability and allows partial transfer of load away from the spine. Because twisting is a common mechanism of low-back injuries, this study was undertaken to determine if trunk rotation results in a decrease in the extrinsic stability of the spine. We studied the effects of changes in trunk posture on intra-abdominal pressure generated during a maximum effort Valsalva's maneuver (IAP max) in eight healthy volunteers. IAP max during standing combined with trunk rotation was found to be significantly lower than IAP max during standing straight (p < 0.05). IAP max during forward flexion combined with trunk rotation was significantly lower than during forward flexion (p < 0.01). The results of our study indicate that trunk rotation adversely effects the ability to perform a Valsalva's maneuver. We conclude that extrinsic stability of the spine is at a biomechanical disadvantage when the trunk is rotated and thus may be a contributing factor to twisting-type back injuries.
Article
1. The response of the diaphragm to the postural perturbation produced by rapid flexion of the shoulder to a visual stimulus was evaluated in standing subjects. Gastric, oesophageal and transdiaphragmatic pressures were measured together with intramuscular and oesophageal recordings of electromyographic activity (EMG) in the diaphragm. To assess the mechanics of contraction of the diaphragm, dynamic changes in the length of the diaphragm were measured with ultrasonography. 2. With rapid flexion of the shoulder in response to a visual stimulus, EMG activity in the costal and crural diaphragm occurred about 20 ms prior to the onset of deltoid EMG. This anticipatory contraction occurred irrespective of the phase of respiration in which arm movement began. The onset of diaphragm EMG coincided with that of transversus abdominis. 3. Gastric and transdiaphragmatic pressures increased in association with the rapid arm flexion by 13.8 +/- 1.9 (mean +/- S.E.M.) and 13.5 +/- 1.8 cmH2O, respectively. The increases occurred 49 +/- 4 ms after the onset of diaphragm EMG, but preceded the onset of movement of the limb by 63 +/- 7 ms. 4. Ultrasonographic measurements revealed that the costal diaphragm shortened and then lengthened progressively during the increase in transdiaphragmatic pressure. 5. This study provides definitive evidence that the human diaphragm is involved in the control of postural stability during sudden voluntary movement of the limbs.
Article
Currently, intra-abdominal pressure (IAP) is thought to provide stability to the lumbar spine but the exact principles have yet to be specified. A simplified physical model was constructed and theoretical calculations performed to illustrate a possible intra-abdominal pressure mechanism for stabilizing the spine. The model consisted of an inverted pendulum with linear springs representing abdominal and erector spinae muscle groups. The IAP force was simulated with a pneumatic piston activated with compressed air. The critical load of the model was calculated theoretically based on the minimum potential energy principle and obtained experimentally by increasing weight on the model until the point of buckling. Two distinct mechanisms were simulated separately and in combination. One was antagonistic flexor extensor muscle coactivation and the second was abdominal muscle activation along with generation of IAP. Both mechanisms were effective in stabilizing the model of a lumbar spine. The critical load and therefore the stability of the spine model increased with either increased antagonistic muscle coactivation forces or increased IAP along with increased abdominal spring force. Both mechanisms were also effective in providing mechanical stability to the spine model when activated simultaneously. Theoretical calculation of the critical load agreed very well with experimental results (95.5% average error). The IAP mechanism for stabilizing the lumbar spine appears preferable in tasks that demand trunk extensor moment such as lifting or jumping. This mechanism can increase spine stability without the additional coactivation of erector spinae muscles.
Article
This investigation was designed to examine the relationship between breathing and prehension movements during object manipulation. Seated subjects (n=12) wore a facemask that was attached to a pneumotachometer which measured airflow. Initially, subjects completed baseline trials that were preceded and followed by an object lift. Subsequently, in response to an auditory signal the subjects reached forward, grasped and lifted an instrumented object that weighed either 150 g or 1000 g while their fingertip forces and movements were measured. The auditory signal was triggered by airflow in response to four experimental conditions (1) expiratory onset (2) inspiratory onset (3) mid-inspiration and (4) mid-expiration. Five trials for each of the four conditions were completed with each weight. The results revealed that inspiratory time was longer under baseline conditions after the subjects lifted the 150 g object as compared to the 1000 g object. In addition, the response latency and reach duration were significantly slower for the 150 g object compared to the 1000 g object during the experimental trials. These temporal measures were significantly correlated to inspiratory time for three of the four experimental conditions but no significant relationship with expiratory time was found. Lastly, lifting of the object occurred during expiration during most experimental conditions. We conclude that an adaptive process is formulated for both the motor and respiratory system in response to changes in motor output and/or sensory inputs associated with object manipulation, that might manifest itself in the pattern of breathing subsequent to removal of these stimuli. Furthermore, we suggest that motor inputs associated with the initiation of object manipulation interact with the control of respiratory timing so that the motor and respiratory systems are coupled. We speculate that this relationship may ensure that some motor tasks are performed during expiration to take advantage of changes in intrathoracic pressure that assist in postural maintenance during completion of the task.
Article
We previously found that weight lifters could generate greater inspiratory pressures and had more diaphragm mass than control subjects. We postulated that the weight-lifting activity itself provided a strength-training stimulus to the diaphragm. To evaluate the extent to which the diaphragm is recruited during strenuous nonrespiratory activities, we measured transdiaphragmatic pressure (Pdi) in six healthy subjects during biceps curls, bench press, power lift, and sit-ups. Each maneuver was performed with and without added weight (control), and with and without an abdominal binder. The weighted maneuvers were performed either during inspiration or expiration. Maximal static transdiaphragmatic pressure (Pdi(max)) was measured during a combined inspiratory and expulsive maneuver. Group mean values of Pdi increased during all activities when compared with control (57 +/- 24 versus 18 +/- 10 cm H(2)O [mean +/- SD] [p < 0.001]), as task intensity increased (98 +/- 14 versus 35 +/- 13 cm H(2)O for high- and low-intensity activities, respectively) (p < 0.001), and with abdominal binding (75 +/- 25 versus 59 +/- 25 cm H(2)O) (p < 0.05). Peak levels of Pdi attained during the activities were 126 +/- 11 cm H(2)O or 0.65 +/- 0.09 of Pdi(max). Changes in gastric pressure accounted for 85 +/- 4% of the increase in Pdi during the activities whereas it accounted for only 58 +/- 9% of the rise in Pdi during the control activities (p < 0.001). We conclude that during a range of weight-lifting activities, the diaphragm is recruited and Pdi is raised to a level that may provide a significant strength-training stimulus to the diaphragm.
Article
1. Respiratory activity of the diaphragm and other respiratory muscles is normally co-ordinated with their other functions, such as for postural control of the trunk when the limbs move. The integration may occur by summation of two inputs at the respiratory motoneurons. The present study investigated whether postural activity of the diaphragm changed when respiratory drive increased with hypercapnoea. 2. Electromyographic (EMG) recordings of the diaphragm and other trunk muscles were made with intramuscular electrodes in 13 healthy volunteers. Under control conditions and while breathing through increased dead-space, subjects made rapid repetitive arm movements to disturb the stability of the spine for four periods each lasting 10 s, separated by 50 s. 3. End-tidal CO(2) and ventilation increased for the first 60-120 s of the trial then reached a plateau. During rapid arm movement at the start of dead-space breathing, diaphragm EMG became tonic with superimposed modulation at the frequencies of respiration and arm movement. However, when the arm was moved after 60 s of hypercapnoea, the tonic diaphragm EMG during expiration and the phasic activity with arm movement were reduced or absent. Similar changes occurred for the expiratory muscle transversus abdominis, but not for the erector spinae. The mean amplitude of intra-abdominal pressure and the phasic changes with arm movement were reduced after 60 s of hypercapnoea. 4. The present data suggest that increased central respiratory drive may attenuate the postural commands reaching motoneurons. This attenuation can affect the key inspiratory and expiratory muscles and is likely to be co-ordinated at a pre-motoneuronal site.
Article
The purpose of the present study was to investigate whether increased intra-abdominal pressure (IAP) can be achieved without elevating the overall trunk muscle co-contraction that causes increased spine compression force. Ten subjects performed isometric trunk flexion, extension, and lateral bending exertions while generating 0%, 40% and 80% of their maximal IAP or while co-contracting trunk muscles without consciously raising IAP. An additional three subjects performed a variety of ramp IAP, co-contraction and isometric exertion tasks while holding their breaths and while exhaling. An 18 degree-of-freedom, electromyogram (EMG)-assisted biomechanical model was used to quantify trunk muscle co-contraction with calculations of spine compression force and stability. Spine stability and compression force increased proportionally with increased IAP regardless of whether the subjects intentionally generated IAP or consciously avoided it. This increase was accomplished with significantly greater co-contraction of 12 major trunk muscles. The EMG activation of all muscles was highly correlated with IAP and intra-thoracic pressure (ITP) ( r from 0.59 to 0.95). Activity of the thoracic erector spinae correlated the best with ITP ( r=0.81), which in turn was correlated with IAP ( r=0.91). It was not possible to co-contract trunk muscles without generating IAP and ITP, or conversely to generate IAP without trunk muscle co-contraction and increased ITP.
Article
In this study, sudden load was applied to the trunk and situations with alternating low levels of intra-abdominal pressure (IAP) realistic to work situations were compared. The aim was to see if IAP and the small increases in co-contraction of back muscles that follow are capable of increasing the stiffness of the lumbar spine. Nine subjects participated in ten sudden load situations during which they were asked to hold a box and conduct a percentage of maximal IAP. The hip was fixed and the load was applied horizontally on the trunk. EMG, IAP, and movement of the trunk were measured. It was found that IAP of a size likely to appear in work situations, and the concomitant increase in muscle co-activation increased the spine stiffness. This increase in stiffness decreased the movement caused by the sudden load. These results show that both abdominal- and back muscles may have an important role in stabilising the spine, and in decreasing movements caused by sudden loads likely to appear in numerous work
Article
This study focused on intra-abdominal pressure (IAP) during sudden trunk loads. Ten participants were exposed to heavy, sudden trunk loads as they might occur during patient handling. The aim was to study the development of intra-abdominal pressure when well-trained participants cope with heavy, sudden trunk loads. It is hypothesized that high IAP develops sufficiently fast to be present when the large torques act on the low-back structures. Well-trained sportsmen expose themselves to heavy sudden loads of the trunk without getting injured, but it is unknown how they cope with these loads. Do they use IAP? IAP is believed to play a significant role in spine stability, but this has only been documented in experimental studies with light trunk loads. Ten well-trained judo and jujitsu fighters were exposed to heavy sudden trunk loads through imitated patient handling situations in which the patient fell, and the fighters were to hold the patient and prevent the fall. IAP was measured with a catheter in the stomach. Along with the IAP measurement, the load on the low back during the patient falls was quantified by a three-dimensional dynamic biomechanical calculation of the torques and the compression at the L4/L5 joint. High IAP developed quickly and timed in relation to the external torque when the fighters were exposed to a sudden patient fall. When the trunk load was heavy and sudden, IAP was developed to be present at the time when low-back structures had to cope with the large load. High IAP was developed sufficiently fast to be present when the low-back structures had to cope with the large torques released from the sudden trunk loading.
Article
This was a repeated measures study examining 11 asymptomatic subjects while performing dynamic lifting using various postures, loads, and breath control methods. To examine the effects of breath control on magnitude and timing of intra-abdominal pressure during dynamic lifting. Intra-abdominal pressure has been shown to increase consistently during static and dynamic lifting tasks. The relationship between breath control and intra-abdominal pressure during lifting is not clear. Eleven healthy subjects were tested using lifting trials consisting of two levels of posture and load and four levels of breath control (natural breathing, inhalation-hold, exhalation-hold, inhalation-exhalation). Intra-abdominal pressure was measured using a microtip pressure transducer placed within the stomach through the nose. Timing of intra-abdominal pressure was determined relative to lift-off of the weights. Repeated measures analysis of variance was used to determine the effect of breath control, posture, and load on intra-abdominal pressure magnitude and timing. There was a significant effect of breath control (P < 0.018) and load (P < 0.002), but not of posture (P < 0.434), on intra-abdominal pressure magnitude. The inhalation-hold form of breath control produced significantly greater peak intra-abdominal pressure than all other forms of breath control (P < 0.000 for all comparisons). No other comparisons among levels of breath were significantly different. No significant main effects of breath control were found relative to intra-abdominal pressure timing. Breath control is a significant factor in the generation of intra-abdominal pressure magnitude during lifting tasks. The effects of respiration should be controlled in studies analyzing intra-abdominal pressure during lifting.
Article
Ten participants were exposed to heavy sudden trunk loads as they might occur during patient handling. The aim was to observe if well-trained men and women use their full rate of intra-abdominal pressure (IAP) development when exposed to heavy sudden trunk loads. Further, to elucidate to what degree the rectus abdominus muscle is activated when the IAP is developed. Well-trained judo fighters are used to heavy sudden trunk loads and can produce a high IAP. It is unknown whether they use their full potential. IAP can increase the spinal stability and has been suggested to unload the spine. The unloading effect will, however, disappear if the development of the IAP demands substantial activity in the vertical fibers of the abdominal muscles. Five male and five female well-trained judo and jujitsu fighters were exposed to heavy sudden trunk loadings through imitated patient handling situations where the patient fell and the fighters should hold the patient and prevent the fall. IAP was measured with a catheter in the stomach. Along with the IAP measurement, EMG was measured on the abdominal muscles, and the load on the low back was quantified by a three-dimensional dynamic biomechanical calculation of the torques at the L4-L5 joint. The well-trained judo fighters did not use their full potential of the IAP development when exposed to the heavy sudden trunk loads, but the women had to use a higher level of their IAP and extension torque capacity to comply with the heavy loads. The rectus abdominus muscle does not contribute to the IAP development when the trunk is exposed to a sudden heavy load.
Article
Intra-abdominal pressure (IAP) increases during many tasks and has been argued to increase stability and stiffness of the spine. Although several studies have shown a relationship between the IAP increase and spinal stability, it has been impossible to determine whether this augmentation of mechanical support for the spine is due to the increase in IAP or the abdominal muscle activity which contributes to it. The present study determined whether spinal stiffness increased when IAP increased without concurrent activity of the abdominal and back extensor muscles. A sustained increase in IAP was evoked by tetanic stimulation of the phrenic nerves either unilaterally or bilaterally at 20 Hz (for 5 s) via percutaneous electrodes in three subjects. Spinal stiffness was measured as the force required to displace an indentor over the L4 or L2 spinous process with the subjects lying prone. Stiffness was measured as the slope of the regression line fitted to the linear region of the force-displacement curve. Tetanic stimulation of the diaphragm increased IAP by 27-61% of a maximal voluntary pressure increase and increased the stiffness of the spine by 8-31% of resting levels. The increase in spinal stiffness was positively correlated with the size of the IAP increase. IAP increased stiffness at L2 and L4 level. The results of this study provide evidence that the stiffness of the lumbar spine is increased when IAP is elevated.
Article
To investigate the different muscle activation patterns around the abdomino-pelvic cavity in continent women and their effect on pressure generation during a correct pelvic floor muscle (PFM) contraction and a Valsalva maneuver. Thirteen continent women were assessed. Abdominal, chest wall, and PFM activity and vaginal and intra-abdominal pressure (IAP), were recorded during two tasks: PFM contraction and Valsalva whilst bladder base position was monitored on trans-abdominal ultrasound. A correct PFM contraction was defined as one that resulted in bladder base elevation and a Valsalva resulted in bladder base depression. Comparison of the mean of the normalized EMG activity of all the individual muscle groups was significantly different between PFM contraction and Valsalva (P = 0.04). During a correct PFM contraction, the PFM were more active than during Valsalva (P = 0.001). During Valsalva, all the abdominal muscles (IO (P = 0.006), EO (P < 0.001), RA (P = 0.011)), and the chest wall (P < 0.001) were more active than during PFM contraction. The change in IAP was greater during Valsalva (P = 0.001) but there was no difference in the change in vaginal pressure between PFM contraction and Valsalva (P = 0.971). This study demonstrates a difference in muscle activation patterns between a correct PFM contraction and Valsalva maneuver. It is important to include assessment of the abdominal wall, chest wall, and respiration in the clinical evaluation of women performing PFM exercises as abdominal wall bracing combined with an increase in chest wall activity may cause rises in IAP and PFM descent.
Article
Anecdotal evidence suggests that people hold their breath during lifting tasks in order to increase intra-abdominal pressure (IAP) and thereby increase lumbar stability. Studies have shown that voluntary control of the breath influences IAP and that increases in IAP are related to increases in lumbar stability. However, a description of naturally occurring breath control during whole-body lifting tasks in normal healthy subjects is currently not available. Therefore, the specific aims of this study were to: (1) determine the naturally occurring breath patterns during lifting tasks in healthy subjects; (2) determine the effects of different levels of load during lifting tasks on natural breath control patterns in healthy subjects. The present study enrolled 20 healthy subjects to describe inspired volume and categories of airflow direction (inspiration, expiration, or breath hold) during two self-paced lifts of crates loaded at 5, 15, and 25% of body weight. When the breath pattern was examined across all loads there was a significant increase in the magnitude of inspired volume and the frequency of occurrence of inspiration immediately prior to lift-off. When examining the effect of load on breath patterns, there was a significant increase of inspired volume and occurrence of breath holding when lifting the heavy load compared to the medium and light loads. These results suggest that: (1) distinct patterns of natural breath control occur during lifting tasks; and (2) breath control is responsive to the timing and magnitude of load lifted.
Article
Evidence exists linking breath control to increases in intra-abdominal pressure and lumbar stability. Weight-lifting experts use this evidence as a rationale to suggest that increases in lumbar stability afforded by specific forms of breath control can influence the amount of force produced by the trunk. No studies have examined this issue. Therefore, this study determined whether voluntary control of the breath is related to maximal trunk extension force and if maximal force is correlated to intra-abdominal pressure. Thirteen men and 20 women (mean age: 25.6 years (5.5)) performed a maximal isometric trunk exertion in a knee bent posture using voluntary breath conditions: (1) inhalation prior to exertion with hold during exertion; (2) exhalation prior to exertion with hold during the exertion; (3) inhalation prior to the exertion with exhalation during the exertion. A subset of subjects (n=11) were also simultaneously measured for intra-abdominal pressure. Separate repeated measures ANOVA were used to determine the effects of breath conditions on force and intra-abdominal pressure. Pearson coefficients were used to determine the correlation between force and intra-abdominal pressure. Breath control did not significantly affect isometric force production (P=.089) but did affect intra-abdominal pressure (P=.003). Correlations between force and intra-abdominal pressure in each breath condition were low (range: 0.152-0.583). Although breath control was shown to influence intra-abdominal pressure, it does not appear to influence isometric trunk extension force in a knees bent position. Further, the intra-abdominal pressure produced in such efforts appears to be unrelated to the amount of force produced.
Article
Although progressive resistance training of trunk muscles on devices is very common, today, the effects of increasing resistance on trunk muscle activity during dynamic extension and flexion movements on training devices have not been reported yet. Thirty healthy subjects participated in maximal isometric and submaximal dynamic (at 30%, 50% and 70% of maximum mean torque (MMT)) extension and flexion exercises on Tergumed lumbar training devices. The normalized (as a percentage of maximal voluntary isometric contractions (MVIC)) electromyographic activity of 16 abdominal and back muscles was investigated. The results of the present study indicated that in general, with increasing resistance from 30% MMT to 50% MMT and 70% MMT, the activity of all back muscles during the extension exercises and the activity of all abdominal muscles during the flexion exercises increased significantly. To train strength (>60% of MVIC), low intensities (30% and 50% MMT) appeared sufficient to affect the back muscles, but for the abdominals higher resistance (70% MMT) was required. In contrast to the other back muscles, the lumbar multifidus demonstrated high activity levels during both the extension and the flexion exercises. As the lumbar multifidus is demonstrated to be an important muscle in segmental stabilization of the lumbar spine, this finding may help in understanding the efficacy of rehabilitation programs using specific training devices.
Article
The diaphragm and abdominal muscles can be recruited during nonrespiratory maneuvers. With these maneuvers, transdiaphragmatic pressures are elevated to levels that could potentially provide a strength-training stimulus. To determine whether repeated forceful nonrespiratory maneuvers strengthen the diaphragm, four healthy subjects performed sit-ups and biceps curls 3-4 days/wk for 16 wk and four subjects served as controls. The maximal transdiaphragmatic pressure was measured at baseline and after 16 wk of training. Maximum static inspiratory and expiratory mouth pressures and diaphragm thickness derived from ultrasound were measured at baseline and 8 and 16 wk. After training, there were significant increases in diaphragm thickness [2.5 +/- 0.1 to 3.2 +/- 0.1 mm (mean +/- SD) (P < 0.001)], maximal transdiaphragmatic pressure [198 +/- 21 to 256 +/- 23 cmH2O (P < 0.02)], maximum static inspiratory pressure [134 +/- 22 to 171 +/- 16 cmH2O (P < 0.002)], maximum static expiratory pressure [195 +/- 20 to 267 +/- 40 cmH2O (P < 0.002)], and maximum gastric pressure [161 +/- 5 to 212 +/- 40 cmH2O (P < 0.03)]. These parameters were unchanged in the control group. We conclude that nonrespiratory maneuvers can strengthen the inspiratory and expiratory muscles in healthy individuals. Because diaphragm thickness increased with training, the increase in maximal pressures is unlikely due to a learning effect.
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M. Kawabata Á H. Hamada Á I. Nakamura Á H. Nishizono National Institute of Fitness and Sports, 1 Shiromizu, Kanoya, Kagoshima 891-2393, Japan M. Kawabata Rehabilitation Center, Sagamihara Kyodo Hospital, 2-8-18, Hashimoto, Sagamihara, Kanagawa 229-1188, Japan N. Shima (&) Faculty of Human Wellness, Tokai Gakuen University, 21-233, Nishinohora, Ukigai, Miyoshi, Aichi 470-0207, Japan e-mail: shima@tokaigakuen-u.ac.jp References Al-Bilbeisi F, McCool FD (2000) Diaphragm recruitment during nonrespiratory activities. Am J Respir Crit Care Med 162:456– 459
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