Surface electromyography analysis of core stabilizing muscles during isometric shoulder contractions in athletes with low back pain.

BACKGROUND: The study was carried out in the athletes with and without Low Back Pain (LBP) to determine the surface electromyography activity of core stabilizing muscles while performing isometric shoulder and trunk contractions. STUDY DESIGN: Cross-sectional study. METHODS: This study enlisted the participation of 40 athletes. Group A included 20 athletes (18 males and 2 females) without LBP, and Group B included 20 athletes (12 males and 8 females) with LBP. Athletes with LBP were assessed using the Modified Oswestry Disability Questionnaire (MODQ) and Visual Analog Scale (VAS) to determine their level of disability and pain severity, respectively. EMG activity of the rectus abdominis, external oblique, longissimus, and multifidus was recorded in both groups as they performed bilateral isometric shoulder and trunk contractions. RESULTS: In the LBP group, EMG activity of the rectus abdominis and external oblique muscles was significantly lower (P < 0.05). The LBP group had significantly more multifidus activity (P = 0.03) than the NLBP group. Among all the exercises, bilateral isometric shoulder extension contraction activated the rectus abdominis, right external oblique, and longissimus group of muscles significantly more (P < 0.05) in both groups. In both groups, bilateral isometric shoulder flexion contraction resulted in significantly higher multifidus muscle activation (P = 0.002). CONCLUSION: The activation of core stabilizing muscles was altered in athletes with LBP. When athletes are unable to contract and activate trunk muscles owing to pain, upper extremity exercises can be used to activate these muscles.

Core musculature co-contraction during suspension training exercises.

Suspension training reportedly enhances core musculature co-contraction. This study investigated whether the use of a suspension trainer increases core musculature co-activation during exercises vs. its floor counterpart. Participants were 25 healthy volunteers (16 men, 9 women; age: 27.24 ± 4.02 years). Wireless electromyography electrodes were placed bilaterally at the rectus abdominis (RA), erector spinae (ES), and abdominal obliques (OB). Test order (push-up, bridge, and prone plank) was randomized (exercise and condition) with a 3-min rest period between tests. Co-contraction ratios between muscle groups were estimated by root mean square. Ratios (RA/ES, RA/OB, ES/OB) were analyzed using paired t-tests (P ≤ .05). For all floor exercises, co-contraction of core musculature was significantly higher than suspension trainer. During suspension training, perturbations due to increased agonist activation without similar increases in antagonists may be too intense for untrained or injured individuals. Individuals lacking muscle control to recruit muscles concurrently may benefit from mastering traditional floor exercises to promote joint stiffness and stability before suspension trainer exercises.

Application of Feedback Type on Performance of Abdominal Drawing-In Maneuver in Healthy Adults: A Quasi-Experimental Study of Motor Control and Motor Learning.

OBJECTIVE: The aim of this study was to compare the effects of verbal, tactile-verbal, and visual feedback on muscle activation of the lumbar stabilizers relative to extremity movers during an abdominal drawing-in maneuver when feedback is withheld. METHODS: This quasi-experimental study equally divided 54 healthy adults into 3 feedback groups (verbal, tactile-verbal, and visual) who trained twice per week over a 4-week period to perform supine abdominal drawing-in maneuvers. The percentage of maximum voluntary isometric contraction of rectus abdominis, multifidus (MF), erector spinae, and hamstrings (HS) as an outcome measure was acquired using surface electromyography. A 2-way factorial analysis of variance with bootstrapping allowed for comparison of post-pre difference scores across the interaction of feedback and muscle groups. RESULTS: Hamstring activation decreased in those receiving tactile-verbal feedback relative to an increase in participants given visual feedback. Furthermore, when using verbal feedback, HS activity increased relative to a decline in rectus abdominis, and when presenting visual feedback, HS activity increased relative to a decrease in MF. However, no post-pre changes were seen across muscles with tactile-verbal feedback. CONCLUSION: Although tactile-verbal feedback did not increase MF recruitment, it produced less HS activity than visual feedback. Undesirable HS recruitment may reflect boredom or feedback dependency.

The Effect of Respiratory Phase on Abdominal Muscle Activity During Stable and Unstable Sitting Positions in Individuals With and Without Chronic Low Back Pain.

OBJECTIVE: The aim was to assess the abdominal muscle activities during inspiration and expiration at different sitting positions in individuals with and without chronic low back pain (CLBP). METHODS: This study was conducted on 36 participants (18 with CLBP and 18 healthy controls). Ultrasound imaging was used to assess thickness changes of the transverse abdominis, internal oblique, rectus abdominis, and external oblique muscles. Muscle thickness was measured during inspiration and expiration under 3 different stability levels: sitting on a chair, sitting on a gym ball, and sitting on a gym ball with lifting the left foot. The muscle thickness measured in these positions was normalized to the actual muscle thickness at rest in supine lying and presented as a percentage of thickness change. RESULTS: Both groups displayed greater abdominal muscle activities as the stability of the surface decreased during both respiratory phases. However, compared with the healthy controls, the CLBP group showed smaller muscle thickness changes in all abdominal muscles, except the external oblique, in both respiration phases while sitting on a gym ball with lifting the left foot. The CLBP group displayed overactivity of the rectus abdominis muscle relative to the healthy controls while sitting on a chair in both respiratory phases. CONCLUSION: The findings of the study indicate that as the stability of the support surface decreases, individuals with CLBP had more difficulty activating all abdominal muscles in a similar manner compared to healthy controls in both respiratory phases, which might affect both respiration and postural stability.

Simultaneous Changes in Abdominal Adipose and Muscle Tissues Following Treatments by High-Intensity Focused Electromagnetic (HIFEM) Technology-Based Device: Computed Tomography Evaluation

Objective: This study investigates the effects of high-intensity focused electromagnetic technology for induction of changes in abdominal muscles and abdominal subcutaneous fat. Methods: 22 male and female subjects (aged 34 to 64, mean BMI, 23.5kg/m2) underwent 8 treatments of the abdomen (2 per week) with a high-intensity focused electromagnetic field device. Subjects were scanned by computed tomography (CT) at baseline and 1 month after the eighth treatment. Sub-umbilical and epi-umbilical slices were used to measure the thickness of subcutaneous fat and abdominal muscles and the abdominal separation. In addition, standardized photographs, weight, and circumference measurements were collected. Results: While comparing baseline to follow-up measurements, CT data showed on average 17.5% (-3.1±1.9mm) reduction in subcutaneous fat and simultaneous 14.8% (+1.5±0.8mm) thickening of the rectus abdominis muscle. Subjects lost on average 3.9±3.1cm in the waist circumference. Most of the waist reduction effect was achieved after the fourth treatment. The width of abdominal separation decreased by 9.5% (-2.0±1.7mm). All results were highly significant (P<0.01) while weight change was insignificant (P<0.05). Digital photographs showed aesthetic improvement in most subjects. The treatments were painless and without adverse events. Conclusion: Results suggest that the investigated device is effective for abdominal body sculpting. This technology produced rectus muscle hypertrophy and a reduction in subcutaneous abdominal fat. Data suggests 4 treatments as the ideal protocol delivering 86% of the observed improvement. J Drugs Dermatol. 2019;18(11):1098-1102.

Electromyographic evaluation of trunk core muscles during Pilates exercise on different supporting bases.

OBJECTIVE: To evaluate the electromyographic (EMG) activity of the rectus abdominis (RA) and internal oblique (IO) muscles during Pilates exercise on different trunk supporting bases. METHODS: Sixteen female Pilates practitioners participated in the study. EMG of the RA and OI muscles was evaluated during the double leg stretch (DLS) exercise on three different supporting bases - mat, long box, and short box. Trunk stability varies according to the size and type of the base. To normalize the data, the RMS value (EMG) obtained during the DLS exercise was divided by the RMS value from the torque test - the maximal voluntary isometric contraction (MVIC) - and multiplied by 100 (%MVIC). One-way repeated-measured analysis of variance (ANOVA) and Bonferroni tests were used to compare data concerning the supporting bases and Student t-test regarding the muscles (p < 0.05). RESULTS: The comparison among the bases involving each muscle - RA or IO (p < 0.05) - showed significant difference (%MVIC) between the mat and the short box. No significant difference was observed between the muscles concerning the exercise on the mat (p = 0.9266), on the long box (p = 0.5113) and on the short box (p = 0.2972). CONCLUSION: The short box increased the activity of the rectus abdominis and internal oblique muscles during exercise. The DLS exercise was able to challenge the stability of the trunk and thus recruit its stabilizer and mobilizer muscles at the same intensity.

Desempenho muscular respiratório após 12 sessões de treinamento utilizando o aparelho Reformer do método Pilates / Rendimiento muscular respiratorio después de 12 sesiones de entrenamiento utilizando el aparato Reformer del método Pilates / Respiratory muscle performance after 12 sessions of training using the apparatus Reformer of Pilates method

RESUMO Analisar o desempenho muscular respiratório em praticantes de exercícios utilizando o aparelho Reformer do Método Pilates após um treinamento de 12 sessões. O estudo foi realizado com 24 voluntárias, adultas jovens, saudáveis, não tabagistas e não praticantes de exercício físico regular, divididas em Grupo Controle (GC) e Grupo Treinado (GT). Os dois grupos foram submetidos às avaliações inicial e final para análise do desempenho dos músculos respiratórios por meio da manovacuometria e da eletromiografia do músculo reto abdominal. Utilizou-se o teste de Shapiro-Wilk para verificar a normalidade dos dados. A análise de variância two-way foi empregada para as comparações entre os grupos (GT e GC) e os momentos (inicial e final). Para comparações múltiplas, utilizou-se o teste post-hoc de Scheffé. Os GC e GT foram pareados para idade e IMC e, para verificação de diferenças entre os grupos, utilizou-se o teste t pareado. Considerou-se p<0,05 para significância. Houve diferença significante (p=0,039) entre os valores iniciais (116,6 ± 12,8) e finais (120 ± 12,8) de PImáx no GT, assim como entre os valores iniciais (75,3 ± 12,4) e finais (89,3 ± 13,7) de PEmáx nesse mesmo grupo (p=0,0005). Para a eletromiografia houve diferença significante (p=0,03) entre o momento inicial (42,1 ± 15,8) e final (76,7 ± 37,1) do GT para o músculo reto abdominal esquerdo. Conclui-se que as doze sessões de Pilates utilizando o aparelho Reformer melhoraram o desempenho muscular respiratório, aumentando a força da musculatura inspiratória e expiratória.

RESUMEN Evaluar el rendimiento de los músculos respiratorios en practicantes de ejercicios utilizando el método Reformer de Pilates después de un entrenamiento de 12 sesiones. Este estudio se realizó con 24 voluntarios, adultos jóvenes, sanos, no fumadores y no deportistas regulares, siendo divididos en grupo control (GC) y grupo entrenado (GE). El GE participó en un programa de entrenamiento ejecutando 6 ejercicios en el aparato Reformer. Ambos grupos se sometieron a evaluaciones iniciales y finales para analizar el rendimiento de los músculos respiratorios mediante la manovacuometría y la electromiografía del músculo recto abdominal. La prueba de Shapiro-Wilk se utilizó para verificar la normalidad de los datos. Se utilizó el análisis de varianza two-way para las comparaciones entre los grupos (GE y GC) y los momentos (inicial y final). Para comparaciones múltiples, se utilizó la prueba post-hoc de Scheffé. El GC y el GE se emparejaron por edad e IMC mediante la prueba t pareada. Se consideró el valor de significación p<0,05. Se observó una diferencia significativa (p=0,039) entre los valores iniciales (116,6 ± 12,8) y finales (120 ± 12,8) de PImax en el grupo entrenado, así como entre los valores de iniciales (75,3 ± 12,4) y finales (89,3 ± 13,7) de PEmax en el mismo grupo (p=0,0005). En la electromiografía, se observó una diferencia significativa (p=0,03) entre los momentos inicial (42,1 ± 15,8) y final (76,7 ± 37,1) del GE para el músculo recto abdominal izquierdo. Se concluye que las 12 sesiones de Pilates utilizando el aparato Reformer mejoran el rendimiento de los músculos respiratorios, aumentando la fuerza muscular inspiratoria y espiratoria.

ABSTRACT To analyze respiratory muscle performance in exercise practitioners using the Reformer of Pilates method after a 12-session training. This study was carried out with 24 volunteers, healthy young adults, non-smokers and non-regular exercisers, divided into control group (CG) and trained group (TG). The TG participated in a training program executing 6 exercises in the Reformer apparatus. Both groups were submitted to the initial and final evaluations to analyze the performance of the respiratory muscles through the manovacuometry and electromyography of the rectus abdominis muscle. The Shapiro-Wilk test was used to verify the data normality. Two-way analysis of variance was used for the comparisons between the groups (TG and CG) and moments (Initial and Final). For multiple comparisons, the Scheffé post hoc test was used. The groups Control and Trained were paired by age and BMI by paired t test. P <0.05 was considered for significance. A significant difference (p=0039) was observed between the initial (116.6 ± 12.8) and final (120 ± 12.8) values of MIP in the trained group, as well as between baseline values (75.3 ± 12.4) and final (89.3 ± 13.7) of MEP in the same group (p=0.0005). For electromyography, a significant difference (p=0.03) was observed between the initial (42.1 ± 15.8) and final (76.7 ± 37.1) moments of the TG for the left rectus abdominis muscle. The conclusion is that the 12 Pilates sessions using the Reformer apparatus improve respiratory muscle performance, increasing the inspiratory and expiratory muscle strength.

Comparison between the Ki-hap technique and verbal encouragement on activation of abdominal muscles in healthy participants.

The aim of this study was to investigate the comparison between a Ki-hap, defined as a psyching-up technique, and verbal encouragement, defined as a verbal command by a third party, on abdominal muscle activation during performance of the crunch exercise in healthy participants. Ninety participants were randomly allocated to the following three groups: crunch only exercise group (CG, n1 = 30), crunch exercise with Ki-hap group (CKG, n2 = 30), and crunch exercise with Ki-hap and verbal encouragement group (CKVG, n3 = 30). The interventions were conducted over three trials with each group, and measurements involving each participant, were performed by a single examiner. The activation of the rectus abdominis (RA), external oblique (EO), and internal oblique (IO) muscles were evaluated using electromyography (EMG) during performance of the crunch exercise by the CG, CKG, and CKVG. Our results showed a significantly greater increase in the EMG patterns of all muscles during performance of the crunch exercise in the CKG (p < 0.05) compared to those in the CG and CKVG. The results also showed that there was a significantly greater increase in the activation of the EO and IO muscles in the CKVG (p < 0.05) compared with that in the CG. These findings demonstrated that the addition of the Ki-hap technique and verbal encouragement, during performance of the crunch exercise, improves activation of the abdominal muscles.

Ultrasound Evaluation of the Abdominal Wall and Lumbar Multifidus Muscles in Participants Who Practice Pilates: A 1-year Follow-up Case Series.

OBJECTIVE: The purpose of this study was to describe ultrasound (US) changes in muscle thickness produced during automatic activation of the transversus abdominis (TrAb), internal oblique (IO), external oblique (EO), and rectus abdominis (RA), as well as the cross-sectional area (CSA) of the lumbar multifidus (LM), after 1 year of Pilates practice. METHODS: A 1-year follow-up case series study with a convenience sample of 17 participants was performed. Indeed, TrAb, IO, EO, and RA thickness, as well as LM CSA changes during automatic tests were measured by US scanning before and after 1 year of Pilates practice twice per week. Furthermore, quality of life changes using the 36-Item Short Form Health Survey and US measurement comparisons of participants who practiced exercises other than Pilates were described. RESULTS: Statistically significant changes were observed for the RA muscle thickness reduction during the active straight leg raise test (P = .007). Participants who practiced other exercises presented a larger LM CSA and IO thickness, which was statistically significant (P < .05). Statistically significant changes were not observed for the domains of the analyzed 36-Item Short Form Health Survey (P > .05). A direct moderate correlation was observed (r = 0.562, P = .019) between the TrAb thickness before and after a 1-year follow-up. CONCLUSIONS: Long-term Pilates practice may reduce the RA thickness automatic activation during active straight leg raise. Furthermore, LM CSA and IO thickness increases were observed in participants who practice other exercise types in conjunction with Pilates. Despite a moderate positive correlation observed for TrAb thickness, the quality of life did not seem to be modified after long-term Pilates practice.

Abdominal and pelvic floor electromyographic analysis during abdominal hypopressive gymnastics.

INTRODUCTION: Abdominal hypopressive gymnastics appeared as an alternative to traditional abdominal exercises to promote abdominal muscles strength without overloading the pelvic floor muscles (PFM). To determine the activation level of abdominal muscles and PFM and the posture influence in the level of activation in these muscles during abdominal hypopressive gymnastics, we used surface electromyography in young and healthy multipara women. METHODS: This is an observational study with eutrophic nulliparous women aged between 18 and 35 years, with abdominal skinfold less than or equal to 3 cm and active or irregularly active physical activity. Surface electromyography was used for rectus abdominis, external oblique, transversus abdominal/internal oblique (TrA/IO) and PFM assessment in the supine, quadruped and orthostatic (upright standing) positions during abdominal hypopressive gymnastics using normalized electromyographic (%EMG) data. We also analyzed the difference in activation between each muscle and between muscles and positions. RESULTS: Thirty women were evaluated and the mean age was 25.77 years (SD 3.29). The group formed by the TrA/IO muscles and the PFM showed higher %EMG in all the positions assessed, followed by the external oblique and rectus abdominis muscles. A comparison of %EMG of each muscle between the different positions showed differences only in rectus abdominis between the supine and quadruped (p = 0.001) and supine and orthostatic positions (p = 0.004), and in TrA/IO between the supine and orthostatic (p = 0.023) and orthostatic and quadruped positions (p = 0.019). CONCLUSIONS: The results suggest that abdominal hypopressive gymnastics can activate the abdominal muscles and PFM and the position do not have influence on electromyographic activation level of the PFM and external oblique.

Electromyographic activities of the abdominal muscles during 30% and 75% of maximum expiratory pressure.

The aim of this study was to quantify the activities of the rectus abdominis (RA), external oblique (EO), and internal oblique (IO) muscles during 30% and 75% of maximum expiratory pressure (PE max). Fifteen healthy male university students participated in this study. Electromyographic (EMG) activities of the RA, EO, and IO muscles were measured during 30% and 75% of PE max and then normalized relative to maximum voluntary contractions (%MVC). All muscles during 75% of PE max showed significantly higher %MVC compared to that during 30% of PE max (P < 0.01). The EO and IO muscles showed significantly higher %MVC compared to the RA muscle during 30% and 75% of PE max (P < 0.05). Muscle endurance and strength induced by expiratory muscle strength training might be different in each abdominal muscle.

Abdominal muscle activity during breathing in different postural sets in healthy subjects.

OBJECTIVE: This study aims to evaluate the effect of different postural sets on abdominal muscle activity during breathing in healthy subjects. METHODS: Twenty-nine higher education students (20.86 ± 1.48 years; 9 males) breathed at the same rhythm (inspiration: 2 s; expiration: 4 s) in supine, standing, tripod and 4-point-kneeling positions. Surface electromyography was performed to assess the activation intensity of rectus abdominis, external oblique and transversus abdominis/internal oblique muscles during inspiration and expiration. RESULTS: During both breathing phases, the activation intensity of external oblique and transversus abdominis/internal oblique was significantly higher in standing when compared to supine (p ≤ 0.001). No significant differences were found between tripod position and 4-point-kneeling positions. Transversus abdominis/internal oblique activation intensity in these positions was higher than in supine and lower than in standing. CONCLUSIONS: Postural load and gravitational stretch are factors that should be considered in relation to the specific recruitment of abdominal muscles for breathing mechanics.

Electromyographic activity of rectus abdominis muscles during dynamic Pilates abdominal exercises.

OBJECTIVE: To assess the electrical behaviour of the upper rectus abdominis (URA) and lower rectus abdominis (LRA) by electromyography (EMG) during the following dynamic Pilates abdominal exercises: roll up, double leg stretch, coordination, crisscross and foot work. The results were compared with EMG findings of traditional abdominal exercises (sit up and crunch). METHODS: Seventeen female subjects (with no experience of the Pilates method) were recruited. The URA and LRA were evaluated while 12 isotonic contractions were performed using the Pilates principles or traditional abdominal exercises. The data were normalised by a maximal voluntary isometric contraction. Normality was accepted, and ANOVA followed by Tukey test was used to determine data differences (P < 0.05). RESULTS: Pilates exercises double leg stretch, coordination, crisscross and foot work promoted greater muscle activation than traditional exercises, mainly in URA. Thus, these exercises have the potential to be prescribed for muscle strengthening programmes.

The Pilates breathing technique increases the electromyographic amplitude level of the deep abdominal muscles in untrained people.

OBJECTIVE: To evaluate the behaviour of the upper rectus abdominis, lower rectus abdominis and transverse abdominis/internal oblique (TrA/IO) by using surface electromyography during trunk flexion with and without the Pilates breathing technique. METHODS: Nineteen female subjects (without experience of the Pilates method) were recruited. The muscles were evaluated while trunk flexion was performed by using the Pilates breathing technique (POW) and Step Barrel device, followed by another contraction without the technique (NORM). Normality was accepted, and the paired t-test was used to determine data differences (p < 0.05). RESULTS: Significant differences were noted in the amplitude level of activation between TrA/IO-POW and TrA/IO-NORM. The activation amplitude level of TrA/IO-POW significantly increased compared with all the other muscles under the NORM condition. CONCLUSION: The breathing technique of the Pilates method associated with trunk flexion increases TrA/IO electrical activity.

Application of Pilates principles increases paraspinal muscle activation.

OBJECTIVE: To analyze the effect of Pilates principles on the EMG activity of abdominal and paraspinal muscles on stable and unstable surfaces. METHODS: Surface EMG data about the rectus abdominis (RA), iliocostalis (IL) and lumbar multifidus (MU) of 19 participants were collected while performing three repetitions of a crunch exercise in the following conditions: 1) with no Pilates technique and stable surface (nP + S); 2) with no Pilates technique and unstable surface (nP + U); 3) with Pilates technique and stable surface (P + S); 4) with Pilates and unstable surface (P + U). The EMG Fanalysis was conducted using a custom-made Matlab(®) 10. RESULTS: There was no condition effect in the RA iEMG with stable and unstable surfaces (F(1,290) = 0 p = 0.98) and with and without principles (F(1,290) = 1.2 p = 0.27). IL iEMG was higher for the stable surface condition (F(1,290) = 32.3 p < 0.001) with Pilates principles (F(1,290) = 21.9 p < 0.001). The MU iEMG was higher for the stable surface condition with and without Pilates principles (F(1,290) = 84.9 p < 0.001).

Antagonist coactivation of trunk stabilizer muscles during Pilates exercises.

The purpose of this study was to compare the antagonist coactivation of the local and global trunk muscles during mat-based exercises of Skilled Modern Pilates. Twelve women performed five exercises and concurrently, surface EMG from internal oblique (OI), multifidus (MU), rectus abdominis (RA) and iliocostalis lumborum (IL) muscles was recorded bilaterally. The percentage of antagonist coactivation between local (OI/MU) and global muscles (RA/IL) was calculated. Individuals new to the practice of these exercises showed differences in coactivation of the trunk muscles between the exercises and these results were not similar bilaterally. Thus, in clinical practice, the therapist should be aware of factors such as compensation and undesirable rotation movements of the trunk. Moreover, the coactivation of global muscles was higher bilaterally in all exercises analyzed. This suggests that the exercises of Skilled Modern Pilates only should be performed after appropriate learning and correct execution of all principles, mainly the Centering Principle.

The influence of short-term kinesiology taping on force-velocity parameters of the rectus abdominis muscle.

PURPOSE: The purpose of the study was to evaluate the influence of Kinesio-Tex tape on force-velocity parameters (F-V) of the rectus abdominis muscle immediately following application. METHODS: The study group selected consisted of 52 women with a BMI below 23 [kg/m(2)]. The study involved measuring the force-velocity parameters of trunk flexor muscles twice using the Biodex System 3 Pro Set. Analyzed parameters included peak torque [N/m], total work [J], power [W] and percentage ratio of trunk flexor and extensor peak torque. RESULTS: Comparing the results obtained in both tests, for a majority there were no statistically significant differences found in both the study group and control group. CONCLUSIONS: 1. Short-term Kinesiology Taping on the rectus abdominis muscle does not cause a change in force-velocity parameters of trunk flexors. 2. Isolated application on the rectus abdominis muscle may be insufficient to cause a change in force-velocity parameters following such a short application time.

In vitro anticholinergic and antihistaminic activities of Acorus calamus Linn. leaves extracts.

The present investigation was aimed at determining the effects of hexane, acetone, methanol and aqueous extracts of Acorus calamus leaves (ACHE, ACAE, ACME and ACAQE) on cholinergic and histaminic system using isolated frog rectus abdominis muscle and guinea pig ileum. A dose dependent potentiation of Ach response (anticholinesterase like effect) was found with ACAE and ACME at 0.25, 0.5, 0.75 and 1 mg/ml, but at higher dose of ACAE, ACME, ACAQE and ACHE (5, 20 mg/ml) inhibit the Ach response (antinicotinic effect). These results revealed biphasic effect of Acorus calamus leaves extracts on acetylcholine induced contractile response in isolated frog rectus abdominis muscle preparation (i.e. potentiation effect at lower dose and inhibitory effect at higher dose). Studies on isolated guinea pig ileum demonstrated antihistaminic effect in a dose dependent manner (100-1000 µg/ml) with ACAE, ACME and ACAQE. In addition, the dose dependent inhibition of Ach response (antimuscarinic effect) was observed with ACAE and ACME. In conclusion, Acorus calamus leaves extracts exerts antinicotinic, anticholinesterase like activities in isolated frog rectus abdominis muscle and antihistaminic, antimuscarinic effect in guinea pig ileum. It has been suggested that these observed activities can be further studied for therapeutic potential of Acorus calamus leaves in the treatment of cognitive disorders and asthma.

Muscle activity of the upper and lower rectus abdominis during exercises performed on and off a Swiss ball.

This study sought to examine any differences in upper rectus abdominis (URA) and lower rectus abdominis (LRA) muscle activity during four abdominal exercises, the curl-up, Swiss ball curl-up, Swiss ball jackknife and Swiss ball rollout. Fourteen healthy adults (7 males, 7 females, mean age+/-S.D.=21.8+/-3.8 years) performed abdominal exercises in a randomised order following maximal voluntary isometric contraction. Muscle activity of the URA and LRA was assessed using surface electromyography. Results indicated that activity of the URA was significantly greater than muscle activity of the LRA for the curl-up, Swiss ball curl-up and Swiss ball rollout. LRA muscle activity was greater than URA during the jacknife exercise. Muscle activity during the curl-up was significantly lower than muscle activity during the other exercises. To conclude, muscle activity was greater when exercises were performed on a Swiss ball in comparison to a stable surface and LRA muscle activity was maximized during the Swiss ball jacknife.

Surface electromyography of abdominal and back muscles in patients with active scars.

Among the clinical symptoms caused by active scars in the abdominal region, back pain is very frequent. The muscles underneath such a scar appear to be less active on palpation than on the opposite side. To confirm this, 13 patients and 13 healthy controls were examined by surface electromyography (SEMG). We proceeded with SEMG of the straight abdominal muscles on both sides on lifting the head and the shoulders with the subject supine, and of the erector spinae with the patient prone. The patients with active scars were examined before and immediately after soft tissue treatment. SEMG examination showed increased muscle activity of the rectus abdominis in 6 cases on the side of the active scar and in 7 cases on the opposite side. This asymmetry decreased in 7 cases (p=0.045). Asymmetry was also found in the controls. This asymmetry was, however, significantly lesser than in the patients with an active scar (p=0.029). The discrepancy between palpatory and EMG findings is due to hypotony of the soft tissues on the side of the scar, giving the impression (illusion) that muscular activity is diminished on that side.