Variations in abdominal muscle activities of obese females during abdominal bracing exercise in different body positions

AIMS

This study evaluated the activities of the Rectus Abdominis (RA) and Transversus Abdominis (TrA) muscles during abdominal bracing exercises (ABE) in different body positions.

METHODOLOGY

Electrical activities of both components of the RA and TrA muscles were assessed respectively in 25 obese females via surface electromyography during ABE in four (4) different body positions (crook lying, side lying, standing, and sitting). Each trial lasted for five (5) seconds with an hour rest period between trials.

RESULTS

Electrical activities of each of the right RA (p = 0.008) and TrA (p = 0.001) muscles significantly varied across the four trials. For the left components of the RA (p = 0.243) and TrA (p = 0.332) muscles, no significant differences were observed across trials. The highest muscular activities were recorded during the standing trial while the crook lying position resulted in the least muscular activities.

CONCLUSION

For the best results, abdominal bracing exercises should be performed in a standing position. The efficacy of adopting these body positions for long-term rehabilitation purposes should be investigated in future studies.

Effect of Muslim Prayer (Salat) positions on the intra-ocular pressure in healthy young individuals

Purpose

There is a lack of research examining the effects of Muslim prayer (Salat) positions on the intra-ocular pressure (IOP). Considering its involvement with postural changes, this study aimed to investigate the changes in the IOP upon assuming Salat positions before, immediately after, and after 2 minutes of prayer in healthy young adults.

Methods

This prospective, observational study recruited healthy young individuals aged between 18 and 30 years. The IOP measurements were obtained in one eye using Auto Kerato-Refracto-Tonometer TRK-1P, Topcon at baseline before assuming prayer positions, immediately after, and after 2 minutes of the prayer.

Results

Forty female participants were recruited, with a mean age of 21 ± 2.9 years, a mean weight of 59.7 ± 14.8 (kg), and a mean body mass index (BMI) of 23.8 ± 5.7 (kg/m2). Only 16% had a BMI ≥25 kg/m2 (n = 15). All participants started with a mean IOP at baseline of 19.35 ± 1.65 mmHg, which increased to 20 ± 2.38 mmHg and declined to 19.85 ± 2.67 mmHg after 2 minutes of Salat. The difference between the mean IOPs at baseline, immediately after, and after 2 minutes of Salat was not significant (p = 0.06). However, there was a significant difference between the baseline IOP measurements and those immediately after Salat (p = 0.02).

Conclusion

A significant difference was found between the IOP measurements at baseline and immediately after Salat; however, this was not clinically significant. Further investigation is warranted to confirm these findings and explore the effect of a longer duration of Salat in glaucoma and glaucoma suspect patients.

Effect of body position and external ankle load on the pendulum test in adults

BACKGROUND

The pendulum test is commonly used to measure passive stiffness about the knee in healthy and clinical populations. While most studies used an upright position, some studies explored different body positions, particularly with children. Additionally, including external ankle load increases the passive motion of the lower leg in children with Down syndrome. Does combining body position and ankle loading affect joint kinematics and muscle activity of the knee extensors during the pendulum test?

METHODS

Twenty young adults participated in this study. Three body positions were included: 90-dgree upright, 45-degree incline, and 0-degree supine. Three load conditions were tested: no load (0%), and ankle loads equal to 3% and 6% of the subject's body mass. This resulted in a total of 9 conditions. Five trials were collected for each condition.

RESULTS

The upright position elicited a greater number of leg swings and a longer duration of the first knee flexion, while the incline position produced a higher relaxation index. Both ankle load conditions (3% and 6%) increased the magnitude of the first flexion excursion and relaxation index, and the 6% condition produced greater kinematic variables than the 3% load condition. Neither body position nor ankle load elicited muscle activity of the quadriceps.

CONCLUSIONS

Body position and external ankle load can affect the kinematics of leg swing during the pendulum test in healthy young adults. Particularly, ankle loads may increase passive motion about the knee. However, we wonder whether small differences across body positions would be clinically relevant.

Gravity assistance enables liver stiffness measurements to detect liver fibrosis under congestive circumstances

BACKGROUND

As survival has been prolonged owing to surgical and medical improvements, liver failure has become a prognostic determinant in patients with congestive heart diseases. Congestive hepatopathy, an abnormal state of the liver as a result of congestion, insidiously proceed toward end-stage liver disease without effective biomarkers evaluating pathological progression. Regular measurements of shear wave elastography cannot qualify liver fibrosis, which is a prognosticator in any type of chronic liver disease, in cases of congestion because congestion makes the liver stiff without fibrosis. We hypothesized that the effects of congestion and fibrosis on liver stiffness can be dissociated by inducing architectural deformation of the liver to expose structural rigidity.

AIM

To establish a strategy measuring liver stiffness as a reflection of architectural rigidity under congestion.

METHODS

Two-dimensional shear wave elastography (2dSWE) was measured in the supine (Sp) and left decubitus (Ld) positions in 298 consecutive cases as they were subjected to an ultrasound study for various liver diseases. Regions of interest were placed at twelve sites, and the median and robust coefficient of variation were calculated. Numerical data were compared using the Mann-Whitney U or Kruskal-Wallis test followed by Dunn's post-hoc multiple comparisons. The inferior vena cava (IVC) diameters at different body positions were compared using the Wilcoxon matched pairs signed rank test. The number of cases with cardiothoracic ratios greater than or not greater than 50% was compared using Fisher's exact test. A correlation of 2dSWE between different body positions was evaluated by calculating Spearman correlation coefficients.

RESULTS

The IVC diameter was significantly reduced in Ld in subjects with higher 2dSWE values in Ld (LdSWE) than in Sp (SpSWE) (P = 0.007, (average ± SD) 13.9 ± 3.6 vs 13.1 ± 3.4 mm) but not in those with lower LdSWE values (P = 0.32, 13.3 ± 3.5 vs 13.0 ± 3.5 mm). In 81 subjects, SpSWE was increased or decreased in Ld beyond the magnitude of robust coefficient of variation, which suggests that body postural changes induced an alteration of liver stiffness significantly larger than the technical dispersion. Among these subjects, all 37 with normal SpSWE had a higher LdSWE than SpSWE (Normal-to-Hard, SpSWE - LdSWE (∆2dSWE): (minimum-maximum) -0.74 - -0.08 m/sec), whereas in 44 residual subjects with abnormal SpSWE, LdSWE was higher in 27 subjects (Hard-to-Hard, -0.74 - -0.05 m/sec) and lower in 17 subjects (Hard-to-Soft, 0.04 - 0.52 m/sec) than SpSWE. SpSWE was significantly correlated with ∆2dSWE only in Hard-to-Soft (P < 0.0001). ∆2dSWE was larger in each lobe than in the entire liver. When Hard-to-Hard and Hard-to-Soft values were examined for each lobe, fibrosis-4 or platelet counts were significantly higher or lower only for Hard-to-Soft vs Normal-to-Hard cases.

CONCLUSION

Gravity alters the hepatic architecture during body postural changes, causing outflow blockage in hepatic veins. A rigid liver is resistant to structural deformation. Stiff-liver softening in the Ld position suggests a fibrous liver.

Influence of position and stimulation parameters on intracortical inhibition and facilitation in human tongue motor cortex

Paired-pulse transcranial magnetic stimulation (ppTMS) can be used to assess short-interval intracortical inhibitory (SICI) and facilitatory (ICF) networks. Many methodological parameters may however influence the outcome. The aim of the study was to examine the influence of body positions (recline and supine), inter-stimulus intervals (ISI) between the test stimulus (TS) and conditioning stimulus (CS) and intensities of the TS and CS on the degree of SICI and ICF. In studies 1 and 2, fourteen and seventeen healthy volunteers participated respectively. ppTMS was applied over the "hot-spot" of the tongue motor cortex and motor evoked potentials (MEPs) were recorded from contralateral tongue muscles. In study 1, single pulse and three ppTMS ISIs, 2, 10, and 15ms, were applied 8 times each in three blocks (TS: 120%, 140% and 160% of resting motor threshold (rMT); CS: 80% of rMT) in two different body positions (recline and supine) randomly. In study 2, single pulse and four ppTMS ISIs, 2, 2.5, 3, and 3.5ms, were applied 8 times each in randomized order in two blocks (CS: 70% and 80% of rMT; TS: 120% of rMT). There was a significant effect of body position (P=0.049), TS intensities (P<0.001) and ISIs (P<0.001) and interaction between intensity and ISIs (P=0.042) in study 1. In study 2, there was a significant effect of ISI (P<0.001) but not CS intensity (P=0.984) on MEP amplitude. These results may be applied in future studies on the mechanisms of cortical plasticity in the tongue motor pathways using ppTMS and SICI and ICF.