Objective: To investigate the present situation of pelvic floor muscle strength, and to analyze the factors affecting pelvic floor muscle strength. Methods: The data of patients who were admitted into the general outpatient department of gynecology, Peking University People's Hospital from October 2021 to April 2022 were collected, and the patients who met the exclusion criteria were included in this cross sectional study. The patient's age, height, weight, education level, defecation way and defecation time, birth history, maximum newborn birth weight, occupational physical activity, sedentary time, menopause, family history and disease history were recorded by questionnaire. Morphological indexes such as waist circumference, abdomen circumference and hip circumference were measured with tape measure. Handgrip strength level was measured with grip strength instrument. After performing routine gynecological examinations, the pelvic floor muscle strength was evaluated by palpation with modified Oxford grading scale (MOS). MOS grade>3 was taken as normal group and ≤3 as decreased group. Binary logistic regression was used to investigate the related factors of deceased pelvic floor muscle strength. Results: A total of 929 patients were included in the study, and the average MOS grade was 2.8±1.2. By univariate analysis, birth history, menopausal time, defecation time, handgrip strength level, waist circumference and abdominal circumference were related to the decrease of pelvic floor muscle strength (all P<0.05). By binary logistic regression analysis, the level of handgrip strength (OR=0.913, 95%CI: 0.883-0.945; P<0.001) was correlated with normal pelvic floor muscle strength; waist circumference (OR=1.025, 95%CI: 1.005-1.046; P=0.016), birth history (OR=2.224, 95%CI: 1.570-3.149; P<0.001), sedentary time> 8 hours (OR=2.073, 95%CI: 1.198-3.587; P=0.009) were associated with the decrease of pelvic floor muscle strength. Conclusions: The level of handgrip strength is related to the normal pelvic floor muscle strength of females, while the waist circumference, birth history and sedentary time>8 hours are related to the decrease of pelvic floor muscle strength of females. In order to prevent the decrease of pelvic floor muscle strength, it is necessary to carry out relevant health education, enhance exercise, improve the overall strength level, reduce daily sedentary time, maintain symmetry, and carry out comprehensive overall intervention to improve pelvic floor muscle function.
Adult ; Female ; Humans ; Cross-Sectional Studies ; Gynecology ; Hand Strength ; Muscle Contraction/physiology* ; Muscle Strength/physiology* ; Outpatients ; Pelvic Floor/physiology*

OBJECTIVE: To explore the role of endoplasmic reticulum ryanodine receptor 1 (RyR1) expression and phosphorylation in sepsis- induced diaphragm dysfunction. METHODS: Thirty SPF male SD rats were randomized equally into 5 groups, including a sham-operated group, 3 sepsis model groups observed at 6, 12, or 24 h following cecal ligation and perforation (CLP; CLP-6h, CLP-12h, and CLP-24h groups, respectively), and a CLP-24h group with a single intraperitoneal injection of KN- 93 immediately after the operation (CLP-24h+KN-93 group). At the indicated time points, diaphragm samples were collected for measurement of compound muscle action potential (CMAP), fatigue index of the isolated diaphragm and fitted frequencycontraction curves. The protein expression levels of CaMK Ⅱ, RyR1 and P-RyR1 in the diaphragm were detected using Western blotting. RESULTS: In the rat models of sepsis, the amplitude of diaphragm CMAP decreased and its duration increased with time following CLP, and the changes were the most obvious at 24 h and significantly attenuated by KN-93 treatment (P < 0.05). The diaphragm fatigue index increased progressively following CLP (P < 0.05) irrespective of KN- 93 treatment (P>0.05). The frequency-contraction curve of the diaphragm muscle decreased progressively following CLP, and was significantly lower in CLP-24 h group than in CLP-24 h+KN-93 group (P < 0.05). Compared with that in the sham-operated group, RyR1 expression level in the diaphragm was significantly lowered at 24 h (P < 0.05) but not at 6 or 12 following CLP, irrespective of KN-93 treatment; The expression level of P-RyR1 increased gradually with time after CLP, and was significantly lowered by KN-93 treatment at 24 h following CLP (P < 0.05). The expression level of CaMKⅡ increased significantly at 24 h following CLP, and was obviously lowered by KN-93 treatment (P < 0.05). CONCLUSION Sepsis causes diaphragmatic dysfunction by enhancing CaMK Ⅱ expression and RyR1 receptor phosphorylation in the endoplasmic reticulum of the diaphragm.
Rats ; Male ; Animals ; Diaphragm/metabolism* ; Ryanodine Receptor Calcium Release Channel/metabolism* ; Rats, Sprague-Dawley ; Phosphorylation ; Muscle Contraction/physiology* ; Endoplasmic Reticulum ; Sepsis/metabolism*

OBJECTIVE: To evaluate the antidiarrheal effect of ethanol extract of Glycyrrhiza uralensis Fisch root (GFR) in vivo and jejunal contraction in vitro. METHODS: In vivo, 50 mice were divided into negative control, positive control (verapamil), low-, medium- and high-dose GFR (250, 500, 1,000 mg/kg) groups by a random number table, 10 mice in each group. The antidiarrheal activity was evaluated in castor oil-induced diarrhea mice model by evacuation index (EI). In vitro, the effects of GFR (0.01, 0.03, 0.1, 0.3, 1, 3, and 10 g/L) on the spontaneous contraction of isolated smooth muscle of rabbit jejunum and contraction of pretreated by Acetylcholine (ACh, 10 µmol/L) and KCl (60 mmol/L) were observed for 200 s. In addition, CaCl₂ was accumulated to further study its mechanism after pretreating jejunal smooth muscle with GFR (1 and 3 g/L) or verapamil (0.03 and 0.1 µmol/L) in a Ca²⁺-free-high-K⁺ solution containing ethylene diamine tetraacetic acid (EDTA). RESULTS: GFR (500 and 1,000 mg/kg) significantly reduced EI in castor oil-induced diarrhea model mice (P<0.01). Meanwhile, GFR (0.01, 0.03, 0.1, 0.3, 1, 3, and 10 g/L) inhibited the spontaneous contraction of rabbit jejunum (P<0.05 or P<0.01). Contraction of jejunums samples pretreated by ACh and KCl with 50% effective concentration (EC₅₀) values was 1.05 (0.71-1.24), 0.34 (0.29-0.41) and 0.15 (0.11-0.20) g/L, respectively. In addition, GFR moved the concentration-effect curve of CaCl₂ down to the right, showing a similar effect to verapamil. CONCLUSIONS GFR can effectively against diarrhea and inhibit intestinal contraction, and these antidiarrheal effects may be based on blocking L-type Ca²⁺ channels and muscarinic receptors.
Mice ; Rabbits ; Animals ; Antidiarrheals/adverse effects* ; Jejunum ; Glycyrrhiza uralensis ; Castor Oil/adverse effects* ; Calcium Chloride/adverse effects* ; Diarrhea/drug therapy* ; Plant Extracts/adverse effects* ; Verapamil/adverse effects* ; Muscle Contraction

Lower limb ankle exoskeletons have been used to improve walking efficiency and assist the elderly and patients with motor dysfunction in daily activities or rehabilitation training, while the assistance patterns may influence the wearer's lower limb muscle activities and coordination patterns. In this paper, we aim to evaluate the effects of different ankle exoskeleton assistance patterns on wearer's lower limb muscle activities and coordination patterns. A tethered ankle exoskeleton with nine assistance patterns that combined with differenet actuation timing values and torque magnitude levels was used to assist human walking. Lower limb muscle surface electromyography signals were collected from 7 participants walking on a treadmill at a speed of 1.25 m/s. Results showed that the soleus muscle activities were significantly reduced during assisted walking. In one assistance pattern with peak time in 49% of stride and peak torque at 0.7 N·m/kg, the soleus muscle activity was decreased by (38.5 ± 10.8)%. Compared with actuation timing, the assistance torque magnitude had a more significant influence on soleus muscle activity. In all assistance patterns, the eight lower limb muscle activities could be decomposed to five basic muscle synergies. The muscle synergies changed little under assistance with appropriate actuation timing and torque magnitude. Besides, co-contraction indexs of soleus and tibialis anterior, rectus femoris and semitendinosus under exoskeleton assistance were higher than normal walking. Our results are expected to help to understand how healthy wearers adjust their neuromuscular control mechanisms to adapt to different exoskeleton assistance patterns, and provide reference to select appropriate assistance to improve walking efficiency.
Aged ; Ankle/physiology* ; Ankle Joint/physiology* ; Biomechanical Phenomena/physiology* ; Electromyography ; Exoskeleton Device ; Gait/physiology* ; Humans ; Muscle Contraction ; Muscle, Skeletal/physiology* ; Walking/physiology*

Objective To evaluate lateral pterygoid muscle(LPM)contraction in the patients with temporomandibular disorders(TMD)based on 3D-T2 weighted imaging(3D-T2WI).Multiplanar reconstruction(MPR)was employed to measure the length of LPM in the images taken in closed-and open-mouth positions. Methods Seventeen TMD patients [age of(29.82±10.70)years,males/females=8/9] and 13 normal volunteers [control,age of(23.54±3.31)years,males/females=6/7] received 3D-T2WI of the temporomandibular joints in closed-and open-mouth positions from November 2019 to April 2020 in Department of Radiology,Hainan Hospital of Chinese PLA General Hospital.According to the position of the discs,the subjects were classified into the following groups:TMD with disc displacement without reduction(TMD-DDwoR),TMD with disc displacement with reduction(TMD-DDwR),TMD without disc displacement(TMDwoDD),and normal control without disc displacement(NCwoDD).MPR was employed to measure the maximal length of the superior belly of LPM.One-way analysis of variance,receiver operating characteristic curve,and permutation test were employed for the statistical analyses. Results The contraction of LPM was significantly shorter in TMD-DDwoR group [(3.36±1.96)mm] than in TMDwoDD group [(7.90±3.95)mm],NCwoDD group [(8.77±3.13)mm](
Adult ; Female ; Humans ; Joint Dislocations ; Magnetic Resonance Imaging ; Male ; Muscle Contraction ; Pterygoid Muscles/diagnostic imaging* ; Temporomandibular Joint Disc ; Temporomandibular Joint Disorders/diagnostic imaging* ; Young Adult

In this paper, a new surface electromyography (sEMG) signal decomposition method based on spatial location is proposed for the high-density sEMG signals in dynamic muscle contraction. Firstly, according to the waveform correlation of each muscle motor units (MU) in each channel, the firing times are extracted, and then the firing times are classified by the spatial location of MU. The MU firing trains are finally obtained. The simulation results show that the accuracy rate of a single MU firing train after classification is more than 91.67%. For real sEMG signals, the accuracy rate to find a same MU by the "two source" method is over (88.3 ± 2.1)%. This paper provides a new idea for dynamic sEMG signal decomposition.
Action Potentials ; Computer Simulation ; Electromyography ; Muscle Contraction ; Muscle, Skeletal

Human motion control system has a high degree of nonlinear characteristics. Through quantitative evaluation of the nonlinear coupling strength between surface electromyogram (sEMG) signals, we can get the functional state of the muscles related to the movement, and then explore the mechanism of human motion control. In this paper, wavelet packet decomposition and : coherence analysis are combined to construct an intermuscular cross-frequency coupling analysis model based on wavelet packet- : coherence. In the elbow flexion and extension state with 30% maximum voluntary contraction force (MVC), sEMG signals of 20 healthy adults were collected. Firstly, the subband components were obtained based on wavelet packet decomposition, and then the : coherence of subband signals was calculated to analyze the coupling characteristics between muscles. The results show that the linear coupling strength (frequency ratio 1:1) of the cooperative and antagonistic pairs is higher than that of the nonlinear coupling (frequency ratio 1:2, 2:1 and 1:3, 3:1) under the elbow flexion motion of 30% MVC; the coupling strength decreases with the increase of frequency ratio for the intermuscular nonlinear coupling, and there is no significant difference between the frequency ratio : and : . The intermuscular coupling in beta and gamma bands is mainly reflected in the linear coupling (1:1), nonlinear coupling of low frequency ratio (1:2, 2:1) between synergetic pair and the linear coupling between antagonistic pairs. The results show that the wavelet packet- : coherence method can qualitatively describe the nonlinear coupling strength between muscles, which provides a theoretical reference for further revealing the mechanism of human motion control and the rehabilitation evaluation of patients with motor dysfunction.
Adult ; Algorithms ; Electromyography ; Humans ; Movement ; Muscle Contraction ; Muscle, Skeletal ; physiology ; Range of Motion, Articular

OBJECTIVE: To investigate the protective effect of melatonin against myocardial ischemia reperfusion (IR) injury in isolated rat hearts and explore the underlying mechanisms. METHODS: The isolated hearts from 40 male SD rats were randomly divided into 4 groups (=10): the control group, where the hearts were perfused with KH solution for 175 min; IR group, where the hearts were subjected to global ischemia for 45 min followed by reperfusion for 120 min; IR+melatonin (Mel+IR) group, where melatonin (5 μmol/L) was administered to the hearts 1 min before ischemia and during the first 5 min of reperfusion, followed by 115 min of reperfusion; and IR+2, 3-butanedione monoxime (IR+BDM) group, where the hearts were treated with BDM (20 mmol/L) in the same manner as melatonin treatment. Myocardial injury in the isolated hearts was assessed based on myocardial injury area, caspase-3 activity, and expressions of cytochrome C and cleaved caspase-3 proteins. Cardiac contracture was assessed using HE staining and by detecting lactate dehydrogenase (LDH) activity and the content of cardiac troponin I (cTnI) in the coronary outflow, measurement of left ventricular end-diastolic pressure (LVEDP) and electron microscopy. The content of ATP in the cardiac tissue was also determined. RESULTS: Compared with those in the control group, the isolated hearts in IR group showed significantly larger myocardial injury area and higher caspase-3 activity and the protein expressions of cytochrome C and cleaved caspase-3 with significantly increased LDH activity and cTnI content in the coronary outflow and elevated LVEDP at the end of reperfusion; HE staining showed obvious fractures of the myocardial fibers and the content of ATP was significantly decreased in the cardiac tissue; electron microscopy revealed the development of contraction bands. In the isolated hearts with IR, treatment with Mel or BDM significantly reduced the myocardial injury area, caspase-3 activity, and protein expressions of cytochrome C and cleaved caspase-3, obviously inhibited LDH activity, lowered the content of cTnI and LVEDP, reduced myocardial fiber fracture, and increased ATP content in the cardiac tissue. Both Mel and BDM inhibited the formation of contraction bands in the isolated hearts with IR injury. CONCLUSIONS Mel can alleviate myocardial IR injury in isolated rat hearts by inhibiting cardiac contracture, the mechanism of which may involve the upregulation of ATP in the cardiac myocytes to lessen the tear of membrane and reduce cell content leakage.
Animals ; Heart ; drug effects ; Male ; Melatonin ; pharmacology ; therapeutic use ; Muscle Contraction ; drug effects ; Myocardial Reperfusion Injury ; drug therapy ; Myocytes, Cardiac ; drug effects ; Rats ; Rats, Sprague-Dawley

Objective To develop a convolutional neural network （CNN） that can identify isokinetic knee exercises moment of force-time diagrams under different levels of efforts. Methods The 200 healthy young volunteers performed concentric isokinetic right knee flexion-extension reciprocating exercises with maximal effort as well as half the effort at angular velocities of 30°/s and 60°/s twice, respectively, with an interval of 45 min. The moment of force-time diagrams were collected. The 200 subjects were randomly divided into the training set （140 subjects） and the testing set （60 subjects）. The moment of force-time diagrams from subjects in the training set were used to train CNN model, and then the fully trained model was used to predict types of curves from the testing set. Random sampling of subjects along with subsequent development of models were performed 3 times. Results Under the circumstances of isokinetic knee exercises with maximal effort and half the effort, 2 400 moment of force-time diagrams were produced, respectively. Classification accuracy rates of the CNN models after the 3 trainings were 91.11%, 90.49% and 92.08%, respectively, and the average accuracy rate was 91.23%. Conclusion The CNN models developed in this study have a good effect on differentiating isokinetic moment of force-time diagrams of maximal effort exercises from those made with half the effort, which can contribute to identifying levels of efforts exerted by subjects during isokinetic knee exercises.
Humans ; Knee ; Knee Joint ; Muscle Contraction ; Muscle, Skeletal ; Neural Networks, Computer

BACKGROUND/AIMS: High-resolution methods have advanced esophageal and anorectal manometry interpretation but are incompletely established for intestinal manometry. We characterized normal fasting duodeno-jejunal manometry parameters not measurable by standard techniques using clustered closely-spaced recordings. METHODS: Ten fasting recordings were performed in 8 healthy controls using catheters with 3–4 gastrointestinal manometry clusters with 1–2 cm channel spacing. Migrating motor complex phase III characteristics were quantified. Spatial-temporal contour plots measured propagation direction and velocity of individual contractions. Coupling was defined by pressure peak continuity within clusters. RESULTS: Twenty-three phase III complexes (11 antral, 12 intestinal origin) with 157 (95% CI, 104–211) minute periodicities, 6.99 (6.25–7.74) minute durations, 10.92 (10.68–11.16) cycle/minute frequencies, 73.6 (67.7–79.5) mmHg maximal amplitudes, and 4.20 (3.18–5.22) cm/minute propagation velocities were recorded. Coupling of individual contractions was 39.1% (32.1–46.1); 63.0% (54.4–71.6) of contractions were antegrade and 32.8% (24.1–41.5) were retrograde. Individual phase III contractions propagated > 35 fold faster (2.48 cm/sec; 95% CI, 2.25–2.71) than complexes themselves. Phase III complexes beyond the proximal jejunum were longer in duration (P = 0.025) and had poorer contractile coupling (P = 0.025) than proximal complexes. Coupling was greater with 1 cm channel spacing vs 2 cm (P < 0.001). CONCLUSIONS: Intestinal manometry using clustered closely-spaced pressure ports characterizes novel antegrade and retrograde propagation and coupling properties which degrade in more distal jejunal segments. Coupling is greater with more closely-spaced recordings. Applying similar methods to dysmotility syndromes will define the relevance of these methods.
Catheters ; Fasting ; Intestines ; Jejunum ; Manometry ; Muscle Contraction ; Myoelectric Complex, Migrating ; Periodicity