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*

OBJECTIVETo determine the anthropometric parameters and the isometric muscle strength in a working population sample in China, and to investigate the relationship between muscle strength and individual attributes, such as age, gender, height and weight.

METHODSThe study population consisted of 146 male and 47 female people including workers, administrators and college students. Four types of muscle strength, i.e., handgrip, arm lift, shoulder lift, and torso pull, were measured.

RESULTSLeft handgrip, right handgrip, arm lift, shoulder lift and torso pull of male workers were (42.07 +/- 7.20), (43.92 +/- 7.14), (26.79 +/- 4.64), (33.79 +/- 6.88), (88.56 +/- 17.98) kg, respectively while those of female workers were (21.29 +/- 5.09), (23.26 +/- 5.47), (13.29 +/- 3.37), (18.52 +/- 4.01), (41.06 +/- 12.04) kg, respectively. The female's strength was about 50% lower than the male's. The strength in the 40 approximately years old group was higher than that in other age groups. There were significant positive correlation between the gender and the isometric strength as well as between the body weight and the isometric strength. If the body weight served as the corrected parameter, there was no significant difference in the handgrip among the groups (P < 0.05), but the torso pull of male workers > college students > administrators. All relative muscle strengths except the torso pull were similar for all age groups.

CONCLUSIONThe body weight as the independent variable can be used for establishing the predictive equation of the muscle strength. Calculation of the relative muscle strength can relieve the interference of the body weight for the muscle strength.

Adolescent ; Adult ; Anthropometry ; Female ; Hand Strength ; physiology ; Humans ; Male ; Middle Aged ; Muscle Contraction ; physiology ; Muscle Strength ; physiology ; Muscle Strength Dynamometer ; Pilot Projects ; Transactional Analysis ; Work Capacity Evaluation

OBJECTIVES: To investigate the link between cigarette smoking and muscle strength in Japanese men. METHODS: We used data on 4249 Japanese men, aged 43.3+/-13.9 years, in this cross-sectional investigation study. Grip strength and leg strength were measured as indicators of overall muscle strength. Meanwhile, subjects' cigarette smoking habits were recorded by trained medical staff. The effect of cigarette smoking on muscle strength was evaluated. RESULTS: A total of 1618 men (38.1%) were smokers and 1481 men (34.9%) exercised regularly. Significant differences in muscle strength were noted between men with and without a Brinkman index of 400 or greater, after adjusting for age. After adjusting for age, height, body weight and exercise habits, associations between the Brinkman index and leg strength and the ratio of leg strength to body weight were attenuated. CONCLUSIONS: Cigarette smoking might be negatively associated with muscle strength, especially grip strength in Japanese men.
Adult ; Body Weight ; Exercise ; Hand Strength/physiology ; Humans ; Japan ; Male ; Middle Aged ; Muscle Strength/*physiology ; *Smoking

Biomechanical evaluation of neck muscles has important significance in the diagnosis and treatment for cervical spondylosis, the neck muscle strength and soft tissue stiffness test is two aspects of biomechanical testing. Isometric muscle testing operation is relatively simple, the cost is lower, which can evaluate the muscle force below grade 3. However, isokinetic muscle strength testing can assess the muscle strength of joint motion in any position. It is hard to distinguish stiffness difference in different soft tissues when the load-displacement curve is used to evaluate the local soft tissue stiffness. Elasticity imaging technique can not only show the elastic differences of different tissues by images, but also quantify the elastic modulus of subcutaneous tissues and muscles respectively. Nevertheless, it is difficult to observe the flexibility of the cervical spine by means of the analysis of the whole neck stiffness. In a word, a variety of test method will conduce not only the biomechanical evaluation of neck muscles, but also making an effective biomechanics mathematical model of neck muscles. Besides, isokinetic muscle testing and the elasticity imaging technology still need further validation and optimization before they are better applied to neck muscles biomechanical testing.
Biomechanical Phenomena ; Humans ; Muscle Strength ; Neck Muscles ; physiology

Evaluation of limbs muscle function is one of the difficult tasks in forensic clinical medicine. Recently, there are more and more cases needed to be evaluated on the limbs muscle function in forensic clinical appraisal. Thus the assessment methods for muscle function have been concerned increasingly. This paper introduces the classification of muscle function and the type of muscle contraction, reviews the assessment methods for muscle function and their application value, such as manual muscle test, simple instrumental muscle test, isokinetic muscle test and electrophysiological test. It has also proposed to evaluate the muscle function with multiple methods comprehensively.
Biomechanical Phenomena ; Electromyography/methods* ; Exercise Test/methods* ; Extremities/physiology* ; Forensic Medicine ; Humans ; Isometric Contraction/physiology* ; Muscle Contraction/physiology* ; Muscle Strength/physiology* ; Muscle Tonus ; Muscle, Skeletal/physiology* ; Muscles/physiology*

OBJECTIVE: To study the objectivity and reliability of needle electromyography and nerve conduction for detection of musculus extensor digitorum brevis strength, which may provide a basis for establishing a quantitative detection of muscle strength in forensic clinical study. METHODS: Forty-four healthy people were enrolled as the subjects, and during toe dorsiflexion, the following items including needle electromyography indexes, motor unit potential (MUP) amplitude, MUP count, recruitment reaction type, and nerve conduction detection indexes, compound muscle action potential (CMAP) amplitude, CMAP latent period and motor nerve conduction velocity (MNCV), were simultaneously detected under the cooperation and disguise condition. RESULTS: Under the cooperation condition, regardless of the same operator or different operators, there were good test-retest reliabilities in MUP amplitude, CMAP amplitude, CMAP latent period and MNCV, while there were normal test-retest reliabilities in MUP count and recruitment reaction type and the repeatability of the same operator was slightly better than the repeatability between different operators. Under the disguise condition, test-retest reliabilities of MUP amplitude, CMAP amplitude, CMAP latent period and MNCV were relatively high, while test-retest reliabilities of MUP count and recruitment reaction type were relatively low. CONCLUSION There are good test-retest reliabilities in MUP amplitude, CMAP amplitude, CMAP latent period and MNCV, which can be conducive to comparison between different operators and results at various times; MUP count and recruitment reaction type, which can be easily affected by subjectivity of operators and examinees, can be used to differentiate whether an examinee disguises or not. The indexes used to objectively judge muscle strength remain to be further investigated.
Electrodes, Implanted ; Electromyography ; Humans ; Muscle Strength/physiology* ; Muscle, Skeletal/innervation* ; Neural Conduction/physiology* ; Reproducibility of Results ; Toes

BACKGROUNDSkeletal muscle dysfunction is one of important systemic manifestations of chronic obstructive pulmonary disease (COPD) and is associated with mortality in patients with COPD, thus quantifying its strength is of great clinical interest and of particular value. Quadriceps maximal volitional contraction (MVC) is often used for the routine measurements of this muscle's strength; while twitch tension (TwQ) evoked by magnetic stimulation of the femoral nerve has been employed for measurement of quadriceps strength non-volitionally. We aimed to investigate the prevalence and severity of skeletal muscle dysfunction in COPD patients by measurement of quadriceps strength with volitional and non-volitional techniques, and to probe into some methodological issues.

METHODSWe recruited 71 COPD patients and 60 control subjects. Quadriceps strength was measured with both maximality of TwQ and MVC force. The reproducibility for TwQ and MVC was investigated using within-occasion variability from three repeated maneuvers.

RESULTSMaximal TwQ was achieved in 121 participants at a mean of 90% of the stimulator's maximum output. The mean maximality of TwQ was decrease by about 44% - 47% in COPD patients as compared with controls (P < 0.05), so was MVC. There was a significant correlation between quadriceps TwQ and MVC, and the mean ratio of TwQ/MVC was 0.29 in controls and 0.33 in patients. The coefficient of variation showed that TwQ yielded lower within-occasion variability than MVC in both groups.

CONCLUSIONSQuadriceps strength is commonly and substantially impaired in patients with COPD, in terms of MVC as well as TwQ. The magnetic stimulation of the femoral nerve presents a higher reproducibility and is a better technique for measurement of quadriceps strength for the general population, especially for those who are too unwell to perform a full MVC; while it may not be applied to subjects who are over-weighted.

Aged ; Female ; Femoral Nerve ; physiology ; Humans ; Male ; Middle Aged ; Muscle Strength ; physiology ; Pulmonary Disease, Chronic Obstructive ; physiopathology ; Quadriceps Muscle ; physiology

OBJECTIVES: To explore the changes of elbow flexor muscle strength after musculocutaneous nerve injury and its correlation with needle electromyography (nEMG) parameters. METHODS: Thirty cases of elbow flexor weakness caused by unilateral brachial plexus injury (involving musculocutaneous nerve) were collected. The elbow flexor muscle strength was evaluated by manual muscle test (MMT) based on Lovett Scale. All subjects were divided into Group A (grade 1 and grade 2, 16 cases) and Group B (grade 3 and grade 4, 14 cases) according to their elbow flexor muscle strength of injured side. The biceps brachii of the injured side and the healthy side were examined by nEMG. The latency and amplitude of the compound muscle action potential (CMAP) were recorded. The type of recruitment response, the mean number of turns and the mean amplitude of recruitment potential were recorded when the subjects performed maximal voluntary contraction. The quantitative elbow flexor muscle strength was measured by portable microFET 2 Manual Muscle Tester. The percentage of residual elbow flexor muscle strength (the ratio of quantitative muscle strength of the injured side to the healthy side) was calculated. The differences of nEMG parameters, quantitative muscle strength and residual elbow flexor muscle strength between the two groups and between the injured side and the healthy side were compared. The correlation between elbow flexor manual muscle strength classification, quantitative muscle strength and nEMG parameters was analyzed. RESULTS: After musculocutaneous nerve injury, the percentage of residual elbow flexor muscle strength in Group B was 23.43% and that in Group A was 4.13%. Elbow flexor manual muscle strength classification was significantly correlated with the type of recruitment response, and the correlation coefficient was 0.886 (P<0.05). The quantitative elbow flexor muscle strength was correlated with the latency and amplitude of CMAP, the mean number of turns and the mean amplitude of recruitment potential, and the correlation coefficients were -0.528, 0.588, 0.465 and 0.426 (P<0.05), respectively. CONCLUSIONS The percentage of residual elbow flexor muscle strength can be used as the basis of muscle strength classification, and the comprehensive application of nEMG parameters can be used to infer quantitative elbow flexor muscle strength.
Humans ; Elbow ; Electromyography ; Musculocutaneous Nerve ; Elbow Joint/physiology* ; Muscle, Skeletal ; Muscle Strength ; Peripheral Nerve Injuries

OBJECTIVE: To study the influence of different positions in the isokinetic muscle test of knees by CON-TREX Biomechanical Test and Training System, so as to select the suitable conditions for forensic identification of muscle strength test. METHODS: Fifty-two healthy volunteers joined the isokinetic muscle strength test in unfixed and fixed position, respectively and in two kinds of angular speed (60 degrees/s and 30 degrees/s). The differences of peak torque (PT) and peak torque angle (PTA) between bilateral knee flexor and extensor were statistically analyzed. RESULTS: In the unfixed position, under the two speed, there was statistically significant difference in PT between bilateral knee flexor and extensor (P < 0.05); while in the fixed position, under the two speed, there was no statistically significant difference (P > 0.05). In any kind of conditions, the PTA of bilateral knee flexor and extensor did not have statistically significant difference (P > 0.05). CONCLUSION The position of the subject influences the results of PT. So the position of subject in knees isokinetic muscle test should be regulated.
Humans ; Knee ; Knee Joint ; Muscle Strength ; Muscle, Skeletal/physiology* ; Muscles ; Posture ; Torque

Muscle strength training plays an important role in improving limb movement function, preventing muscle atrophy and promoting muscle function recovery in patients with various bone and joint diseases. The sports function of elbow joint is closely related to people's daily life activity ability. At present, Chinese muscle strength training devices are depended on import. Therefore, it is of great significance to develop muscle strength training devices. Based on the concepts and characteristics of isometric training, isotonic training, passive training and isokinetic training, in the upper computer, the servo driver and servo motor are controlled through the LabView interface, and the real-time torque is detected by the torque sensor, realizing four training modes. The main parameters of the multi-mode elbow joint muscle strength training device meet the requirements, and the trainers have a good experience.
Elbow Joint ; physiology ; Humans ; Muscle Strength ; Muscle, Skeletal ; Resistance Training ; Torque