Explore the vast range of titles available.

This paper proposes a nonlinear correlation-based wavelet scale selection technology to select the effective wavelet scales for the estimation of handgrip force from surface electromyograms (SEMG). The SEMG signal corresponding to gripping force was collected from extensor and flexor forearm muscles during the force-varying analysis task. We performed a computational sensitivity analysis on the initial nonlinear SEMG-handgrip force model. To explore the nonlinear correlation between ten wavelet scales and handgrip force, a large-scale iteration based on the Monte Carlo simulation was conducted. To choose a suitable combination of scales, we proposed a rule to combine wavelet scales based on the sensitivity of each scale and selected the appropriate combination of wavelet scales based on sequence combination analysis (SCA). The results of SCA indicated that the scale combination VI is suitable for estimating force from the extensors and the combination V is suitable for the flexors. The proposed method was compared to two former methods through prolonged static and force-varying contraction tasks. The experiment results showed that the root mean square errors derived by the proposed method for both static and force-varying contraction tasks were less than 20%. The accuracy and robustness of the handgrip force derived by the proposed method is better than that obtained by the former methods.

Purpose This study investigated the significance of the Global Leadership Initiative on Malnutrition (GLIM) for patients with resected biliary tract cancers. Methods The subjects of this retrospective analysis were 114 patients who underwent radical surgery for cholangiocarcinoma between 2018 and 2023. We analyzed both handgrip force and skeletal muscle area and classified patients as having GLIM malnutrition or modified GLIM malcondition. We also evaluated clinicopathological factors, short-term outcomes, and prognoses. Results The GLIM criteria identified 47 patients (41.2%) with malnutrition and 13 patients (11.4%) with modified GLIM malcondition. Overall survival ( P  = 0.009) and recurrence-free survival ( P  = 0.016) were significantly different between the well-nourished and malnourished patients according to the GLIM criteria. Furthermore, modified GLIM criteria malcondition was a significant prognostic factor for both recurrence-free and overall survival ( P  = 0.002 and P  < 0.001, respectively). Multivariate analysis identified a higher carcinoembryonic antigen level and modified GLIM malcondition as predictors of overall and recurrence-free survival. Pathological stage ≥ III was also a predictor of recurrence-free survival. On comparing the prognoses of modified GLIM malcondition and GLIM malnutrition using the Akaike Information Criteria, the modified GLIM malcondition was identified as a stronger prognostic factor. Conclusion A modified GLIM malcondition can be a highly useful prognostic marker for patients with resected biliary tract cancer.

Infant crying can elicit sensitive caregiving as well as hostility and harsh parenting responses. In the current study (N = 42 females) with a double-blind experimental design, we tested the effect of intranasal oxytocin administration on the use of excessive force using a hand-grip dynamometer during listening to infant cry sounds. Participants’ experiences with harsh parental discipline during childhood were found to moderate the effect of oxytocin administration on the use of excessive force. Participants’ whose parents did not discipline them harshly used less excessive force in the oxytocin condition, but for participants who were disciplined harshly there was no difference between the oxytocin and placebo condition. Such effects were not found during listening to infant laughter. We conclude that early caregiving experiences constitute an important moderator of the prosocial and/or stress-reducing effects of oxytocin. Oxytocin administration may increase trust and cooperation in individuals with supportive backgrounds, but not generate this effect in individuals who as a consequence of unfavorable early caregiving experiences may have a bias toward negative interpretation of social cues.

Various myoelectric prostheses controlled by electromyography (EMG) signals have been developed. However, there have been few studies that provide fast and accurate methods to predict handgrip force from EMG signals. Rapid and precise handgrip force prediction is required, especially for the real-time control system of myoelectric prostheses. In this study, extreme learning machine (ELM) is applied to predict handgrip force from surface EMG signals of forearm muscles. Furthermore, ELM is compared with support vector machine (SVM) and multiple nonlinear regression (MNLR). The below 10 % of the surface EMG and handgrip force signals were cut away, and then the root mean square feature extracted from the modified surface EMG signals was taken as input vector for these three kinds of predicting mechanisms. For the testing dataset, ELM achieved a slightly larger root mean squared error than SVM did and a smaller one than MNLR did. Meanwhile, all three methods showed high correlation coefficients. For the total processing time, ELM and MNLR consumed much less time than SVM did. Experimental results demonstrate that ELM possesses a relatively good accuracy and little consumed time, although SVM is effective for handgrip force estimation in terms of accuracy. Overall, ELM has a promising potential for predicting handgrip force rapidly and precisely.

Background Cancer-related fatigue (CRF) is the most common and distressing symptom reported by breast cancer survivors. The primary aim of this study was to translate and evaluate psychometrically for the first time a Spanish version of the Piper Fatigue Scale-Revised (S-PFS-R). Methods One hundred and eleven women with stage I–IIIA breast cancer who had completed their primary cancer therapy in the previous 6 months with the exception of hormone therapy completed the S-PFS-R, the Profile of Mood States (POMS) Fatigue (POMS-F) and Vigor subscales (POMS-V), and bilateral force handgrip testing. Data analysis included test–retest reliability, construct validity, criterion-related validity, and exploratory factor analyses. Results Test–retest reliability was satisfactory (r > 0.86), and all subscales showed moderate to high construct validity estimates [corrected item-subscale correlations (Pearson r = ≥ 0.65)]. The exploratory factor analysis revealed four dimensions with 75.5 % of the common variance explained. The S-PFS-R total score positively correlated with the POMS-F subscale (r = 0.50–0.78) and negatively with the POMS-V subscale (r = −0.13 to −0.44) confirming criterion-related validity. Negative correlations among force handgrip testing, subscales, and total scores were weak (r = −0.26 to −0.29). Conclusions The Spanish version of PFS-R shows satisfactory psychometric properties in a sample of breast cancer survivors. This is the first study to translate the PFS-R into Spanish and further testing is warranted.

Performing intra-session recovery is important in rock climbing due to the multiple efforts that climbers are required to make in competitions, as well as repeated climbing trials that they carry out during training sessions. Active recovery has been shown to be a better option than passive recovery. However, the type of active recovery that should be done and the influence of the type and quantity of muscle mass activated are not clear. The aim of this study was to compare the effects of recovering with easy climbing (CR) or walking (WR) on markers of fatigue and climbing performance. For this purpose, 14 subjects participated in this randomly assigned crossover protocol completing three two-minute climbing trials separated by two minutes of active recovery with the assigned method. Seven days later participants carried out the same protocol with the other recovery method. Blood lactate (La(-)), rating of perceived exertion (RPE), and heart rate (HR) were analyzed as markers of fatigue and recovery, while meters climbed (MC) and handgrip force (HF) were analyzed for performance. La- values before the last climbing trial (p < 0.05; d = 0.69) and Peak La- values (p < 0.05; d = 0.77) were lower for CR than for WR. Climbers were able to ascend more meters in the set time when following the CR protocol (p < 0.01; d = 0.6), which shows the important role of the active recovery method carried out on climbing performance. There were no differences in HR, HF or RPE between protocols. A more sport-specific recovery protocol, in addition to moving great muscle mass (e.g. lower limbs), seems to enhance recovery and to facilitate lactate removal. For this reason, CR appears to be a more effective active recovery method than WR in sport rock climbing. Key pointsClimbing recovery improved lactate removal in comparison with walking recovery.Subjects were able to climb more meters in a determined time when easy climbing instead of walking during recoveries.Activating both great muscle mass like that of the lower limbs as well as the main fatigue producing muscles (forearms in climbing) seems more effective for recovering than activating just great muscle mass.

Accumulating evidence suggests that the overall level of cortical activation controlling a voluntary motor task that leads to significant muscle fatigue does not decrease as much as the activation level of the motoneuron pool projecting to the muscle. One possible explanation for this “muscle fatigue>cortical fatigue” phenomenon is that the brain is an organ with built-in redundancies: it has multiple motor centers and parallel pathways, and the center of activation may shift from one location to another when neurons in the previous location become fatigued. This hypothesis was tested by estimating the changes of source locations of high-density (64 channels) scalp electroencephalographic (EEG) signals collected during both fatigue and non-fatigue motor tasks. A current dipole model was used to estimate the EEG sources. The fatigue motor task induced significant muscle fatigue, and the non-fatigue task did not. The EEG signal source that indicated the center of brain activation showed substantial location shifts during the fatigue motor task. The shifts could not be explained by variations of source locations caused by error estimated from the non-fatigue task EEG and simulated data. Compared to the non-fatigue condition, the weighted-center of the source locations for all the participants shifted toward the right hemisphere (ipsilateral to the muscle activation), anterior, and inferior cortical regions under the fatigue condition. Fatigue did not alter dipole (source-signal) strength or the overall level of brain activation. The brain may avoid fatigue by shifting neuron populations that participate in a fatiguing motor task.

The relationship between functional MRI (fMRI)-measured brain signal and muscle force and or electromyogram (EMG) is critical in interpreting fMRI data and understanding the control mechanisms of voluntary motor actions. We designed a system that could record joint force and surface EMG online with fMRI data. High-quality force and EMG data were obtained while maintaining the quality of the fMRI brain images. Using this system, we determined the relationship between fMRI-measured brain activation and handgrip force and between fMRI-measured brain signal and EMG of extrinsic finger muscles. Ten volunteers participated in the experiments (only seven subjects' data were analyzed due to excessive noise in the fMRI data of three subjects). The participants exerted 20%, 35%, 50%, 65%, and 80% of the maximal force. During each contraction period, handgrip force, surface EMG of the finger flexor and extensor muscles, and fMRI brain images were acquired. The degree of muscle activation (force and EMG) was directly proportional to the amplitude of the brain signal determined by fMRI in the entire brain and in a number of motor function-related cortical fields, including primary motor, sensory regions, supplementary motor area, premotor, prefrontal, parietal and cingulate cortices, and cerebellum. All the examined brain areas demonstrated a similar relationship between the fMRI signal and force. A stronger fMRI signal during higher force indicates that more cortical output neurons and/or interneurons may participate in generating descending commands and/or processing additional sensory information. The similarity in the relationship between muscle output and fMRI signal in the cortical regions suggests that correlated or networked activation among a number of cortical fields may be necessary for controlling precise static force of finger muscles.

Residual muscle weakness after general anaesthesia, assessed using handgrip strength, was audited in a teaching hospital. The relationships between residual weakness, the use of muscle relaxants and patient characteristics were examined. Handgrip strength was measured preoperatively, one hour postoperatively and one day postoperatively using a hand dynamometer in 151 patients having general anaesthesia. Forty-nine patients received no muscle relaxant, 34 patients received vecuronium and 68 received rocuronium. Patients were managed by their anaesthetist according to that anaesthetist's clinical choice. All patients who received muscle relaxants received neostigmine. One hour postoperatively, there was a decline in handgrip strength of 16% for the no relaxant group, 24% for vecuronium and 29% for rocuronium. The degree of weakness for the relaxant groups was unrelated to age (P=0.89) but was strongly influenced by the patient's sex. Almost all of the increased weakness with relaxants was found in the female patients. The mean decline in handgrip strength in the male patients who received either vecuronium or rocuronium was similar to that seen when relaxants had not been used (P=0.40). One hour postoperatively, female patients showed a marked decrease in handgrip strength after both vecuronium and rocuronium (32% and 34% respectively, combined P=0.01). These results suggest that in usual clinical practice at our institution, female patients are more likely to have residual weakness after muscle relaxants.

Isometric handgrip force, isokinetic knee flexion and extension torque, and anthropometric data were obtained on 67 older men and women (ranging in age from 45 to 75 years, mean 59.7 years). Hydrostatic and skinfold estimates of lean body mass were quite closely correlated with each other in this sample (r = 0.93). Handgrip force, isokinetic knee flexion and extension torque, and lean mass all decreased by 6-8% per decade over the age span examined, although in the men the loss was most marked in terms of handgrip and lean mass, whereas in the women the loss of torque in the knee muscles was dominant. Because of these differences, the handgrip data were only weakly correlated with the isokinetic strength measurements (r = 0.22), and the isokinetic data were more strongly related to lean body mass and body mass. The optimum equation for a field prediction of isokinetic strength in this age group (a combination of age, sex, age-sex interaction and lean body mass) has an error approaching 25%, with a multiple r2 of 0.37, and a standard error of the estimate (s.e.e.) of 24.5%. It is concluded that handgrip data and slow isokinetic torque measurements evaluate relatively independent aspects of the ageing of muscular function.