Efficient data labeling strategies for automated muscle segmentation in lower leg MRIs of Charcot-Marie-Tooth disease patients.

We aimed to develop efficient data labeling strategies for ground truth segmentation in lower-leg magnetic resonance imaging (MRI) of patients with Charcot-Marie-Tooth disease (CMT) and to develop an automated muscle segmentation model using different labeling approaches. The impact of using unlabeled data on model performance was further examined. Using axial T1-weighted MRIs of 120 patients with CMT (60 each with mild and severe intramuscular fat infiltration), we compared the performance of segmentation models obtained using several different labeling strategies. The effect of leveraging unlabeled data on segmentation performance was evaluated by comparing the performances of few-supervised, semi-supervised (mean teacher model), and fully-supervised learning models. We employed a 2D U-Net architecture and assessed its performance by comparing the average Dice coefficients (ADC) using paired t-tests with Bonferroni correction. Among few-supervised models utilizing 10% labeled data, labeling three slices (the uppermost, central, and lowermost slices) per subject exhibited a significantly higher ADC (90.84±3.46%) compared with other strategies using a single image slice per subject (uppermost, 87.79±4.41%; central, 89.42±4.07%; lowermost, 89.29±4.71%, p < 0.0001) or all slices per subject (85.97±9.82%, p < 0.0001). Moreover, semi-supervised learning significantly enhanced the segmentation performance. The semi-supervised model using the three-slices strategy showed the highest segmentation performance (91.03±3.67%) among 10% labeled set models. Fully-supervised model showed an ADC of 91.39±3.76. A three-slice-based labeling strategy for ground truth segmentation is the most efficient method for developing automated muscle segmentation models of CMT lower leg MRI. Additionally, semi-supervised learning with unlabeled data significantly enhances segmentation performance.

Exploring the role of calf circumference as a predisposing factor for intra-hospital delirium: investigating potential gender differences: revealing potential gender variances.

BACKGROUND: Malnutrition and sarcopenia significantly increase the risk of intra-hospital delirium, particularly among older adults. Given the potential correlation between calf circumference (CC) and these conditions, CC emerges as a promising predisposing factor for delirium. This study aims to investigate the independent association between delirium and anthropometric parameters, focusing on evaluating CC's predictive capacity for intra-hospital delirium risk. Additionally, it aims to compare CC's predictive performance with the widely used Mini Nutritional Assessment (MNA), while also considering potential gender disparities. METHODS: This is a retrospective study which enrolled patients aged ≥ 65 years from September 2021 to March 2022 at the Padova Hospital (Italy). Physical characteristics, intra-hospital delirium incidence, and body composition were assessed. Sarcopenia was diagnosed using the 2019 European Consensus criteria. RESULTS: Among 207 subjects, delirium affected 19% of patients. CC showed a significant association with intra-hospital delirium among the analyzed anthropometric parameters. ROC curves indicated that CC's predictive capacity for delirium onset was comparable to MNA (p = 0.98), particularly in women. In a multivariable logistic regression model, female gender and higher cognitive and CC scores emerged as protective factors against delirium onset, with each unit increase in CC associated with a 24% reduction in the odds of delirium. Conversely, sarcopenia did not significantly influence delirium onset. CONCLUSIONS: CC shows promise as a predisposing factor for intra-hospital delirium, similar to MNA, albeit with significant gender differences. CC could serve as a valuable tool for assessing delirium risk among female patients. Further validation of these findings is necessary through larger-scale studies.

Unilateral Plyometric Jump Training Shows Significantly More Effective than Bilateral Training in Improving Both Time to Stabilization and Peak Landing Force in Single-Leg Lend and Hold Test: A Randomized Multi-Arm Study Conducted Among Young Male Basketball Players.

Enhancing peak landing forces and ensuring faster stabilization in the lower limbs during jumping activities can significantly improve performance and decrease the risk of injury among basketball players. This study aimed to compare the effects of unilateral (uPJT) and bilateral plyometric jump training (bPJT) programs on various performance measures, including countermovement jump (CMJ), squat jump (SJ), and single-leg land and hold (SLLH) test outcomes, assessed using force plates. A randomized multi-arm study design was employed, comprising two experimental groups (n = 25; uPJT and n = 25; bPJT) and one control group (n = 25), conducted with youth male regional-level basketball players (16.3 ± 0.6 years old). Participants underwent assessment twice, both before and after an 8-week intervention training period. The uPJT program exclusively involved plyometric drills (e.g., vertical jump exercises; horizontal jump exercises) focusing on single-leg exercises, whereas the bPJT program utilized drills involving both legs simultaneously. The outcomes analyzed included CMJ peak landing force, CMJ peak power, SJ peak force, SJ maximum negative displacement, SLLH time to stabilization, and SLLH peak landing force. The control group exhibited significantly greater SLLH time to stabilization compared to both the uPJT (p < 0.001) and bPJT (p < 0.030) groups. Additionally, time to stabilization was also significantly higher in bPJT than in uPJT (p = 0.042). Comparisons between groups in regards SLLH peak landing force after intervention revealed that the value was significantly smaller in uPJT than in bPJT (p = 0.043) and control (p < 0.001). In the remaining outcomes of CMJ and SJ, both uPJT and bPJT showed significant improvement compared to the control group (p > 0.05), although there was no significant difference between them. In conclusion, our study suggests that utilizing uPJT is equally effective as bPJT in enhancing performance in bilateral jump tests. However, it significantly outperforms bPJT in improving time to stabilization and peak landing forces during single-leg land and hold test. uPJT could be advantageous not for maximizing performance but also for potentially decreasing injury risk by enhancing control and balance during single-leg actions, which are common in basketball.

Characteristics of lymphoedema, in particular midline lymphoedema, after treatment for prostate cancer: a retrospective study.

BACKGROUND: Patients undergoing treatment for prostate cancer may develop lymphoedema of the midline region. This has a substantial impact on a patient's quality of life and its diagnosis is often delayed or missed. Therefore, the purpose of this study is to compare the characteristics of patients with leg and midline lymphoedema to patients with only leg lymphoedema. METHODS: We retrospectively collected patient-, cancer-, lymphoedema- and lymphoedema treatment-related data of 109 men with lymphoedema after treatment for prostate cancer. First, 42 characteristics were compared between both groups. Second, factors predicting presence of midline lymphoedema were explored by multivariable analyses. RESULTS: The mean age of the patients with lymphoedema was 68 ( ±7) years and mean BMI is 28 (±4) kg/m2. Median duration of lymphoedema before the first consultation was 27 (9;55) months. Based on univariable analyses, patients with leg and midline lymphoedema had more frequently upper leg lymphoedema (89% (31/35) vs. 69% (51/74), p = 0.026), skin fibrosis (34% (12/35) vs. 16% (12/74), p = 0.034) and lymphatic reconstructive surgery (9% (3/35) vs. 0% (0/71), p = 0.020) than patients with only leg lymphoedema. Additionally, patients with leg and midline lymphoedema reported less frequently lower leg lymphoedema (77% (27/35) vs. 95% (70/74), p = 0.007). Based on the multivariable analysis, not having lower leg lymphoedema, skin fibrosis, performing self-bandaging and self-manual lymphatic drainage appear to be predictors for having midline lymphoedema. CONCLUSIONS: If patients with lymphoedema after prostate cancer do not have lower leg lymphoedema, have skin fibrosis, perform self-bandaging or self-manual lymphatic drainage, they possibly have midline lymphoedema.

The combined effects of temperature and posture on regional blood flow and haemodynamics.

Under simultaneous ambient temperature and postural stressors, integrated regional blood flow responses are required to maintain blood pressure and thermoregulatory homeostasis. The aim of the present study was to assess the effect of ambient temperature and body posture on regional regulation of microvascular blood flow, specifically in the arms and legs. Participants (N = 11) attended two sessions in which they experienced transient ambient conditions, in a climatic chamber. During each 60-min trial, ambient temperature increased from 15.7 (0.6) °C to 38.9 (0.6) °C followed by a linear decrease, and the participants were either standing or in a supine position throughout the trial; relative humidity in the chamber was maintained at 25.9 (6.6) %. Laser doppler flowmetry of the forearm (SkBFarm) and calf (SkBFcalf), and haemodynamic responses (heart rate, HR; stroke volume, SV; cardiac output, CO; blood pressure, BP), were measured continuously. Analyses of heart rate variability and wavelet transform were also conducted. SkBFarm increased significantly at higher ambient temperatures (p = 0.003), but not SkBFcalf. The standing posture caused lower overall SkBF in both regions throughout the protocol, regardless of temperature (p < 0.001). HR and BP were significantly elevated, and SV significantly lowered, in response to separate and combined effects of higher ambient temperatures and a standing position (all p < 0.05); CO remained unchanged. Mechanistic analyses identified greater sympathetic nerve activation, and higher calf myogenic activation at peak temperatures, in the standing condition. Mechanistically and functionally, arm vasculature responds to modulation from both thermoregulation and baroreceptor activity. The legs, meanwhile, are more sensitive to baroreflex regulatory mechanisms.

Exclusive extragenital lichen sclerosis in a child presenting in a lichen planus distribution.

Lichen sclerosus (LS) is a chronic inflammatory dermatosis primarily affecting the genitalia, commonly characterized by pearly-white papules and plaques. Although predominantly affecting females, LS can manifest across all age groups, with a bimodal distribution observed in prepubescent girls and postmenopausal women. This case report presents an unusual instance of exclusive extragenital LS in a 10-year-old girl, showcasing hyperpigmented patches and wrinkled plaques resembling lichen planus on her forearms and lower legs. Histopathological analysis confirmed LS, revealing distinctive epidermal changes and lymphocytic infiltrates. The absence of mucosal involvement and unique clinical presentation differentiated this case from typical LS manifestations. Treatment with topical clobetasol propionate demonstrated significant improvement in pruritus. Extragenital LS is infrequent, particularly among children, and its diagnosis necessitates a comprehensive clinicopathological correlation. The reported case contributes valuable insights into this uncommon variant, emphasizing the importance of accurate diagnosis and tailored treatment strategies. Additionally, it highlights the efficacy of high-potency topical corticosteroids in managing this condition.

Unique enlargement of human soleus muscle for bipedalism at the expense of the ease of leg swing.

Humans exhibit unique skeletal muscle morphologies that are known to matter in upright bipedalism. However, their relevance to the ease of leg swing, which limits locomotion performance, remains unclear. Here, we aimed to examine muscle mass distribution within the human leg and the effect of each muscle on the ease of leg swing. We calculated the mass, center of mass position, and moment of inertia around the hip extension-flexion axis for all leg muscles by using a publicly available dataset of the 3D reconstruction of the musculoskeletal components in human male and female legs. The leg muscles showed a top-heavy-bottom-light tapering trend; muscles far from the hip joint tended to have smaller masses. Interestingly, however, the soleus exhibited sizable mass for its location. Consequently, the moment of inertia of the soleus was exceptionally greatest, accounting for approximately one-quarter of that of all muscles. These results indicate that compared to the other muscles the soleus muscle has a much larger effect on the leg moment of inertia and uniquely makes humans difficult to swing the leg, although the leg muscles basically show the top-heavy bottom-light tapering trend favoring the leg swing. Our findings highlight a novel functional consequence of human body evolution, suggesting that muscular enlargement for postural stability and endurance capacity has compromised the locomotion speed during the adaptation to bipedalism.

The functions of leg muscles, structures and mechanisms in running.

The actions of the major human leg muscles are well established; however, the functions of these muscle actions during steady running remain unclear. Here, leg structures and mechanisms are considered in terms of their functions in meeting the task of a vehicle acting as an effective machine, supporting body weight during translation with low mechanical work demand and in supplying mechanical work economically. Legs are modelled as a sequence of linkages that predict muscle actions and reveal the varying muscle functions within the integrated leg. Work avoidance is achieved with isometric muscles and linkages that promote a sliding of the hip over the ground contact, resulting in an approximately horizontal path of the centre of mass. Economical work supply requires, for muscle with constrained power, shortening over the entire stance duration; this function is achieved by the hamstrings without disrupting the linkages resulting in work avoidance. In late stance, the two functions occur through coactivation of antagonistic muscles, providing one answer to Lombard's paradox. Quadriceps and hamstring tensions result in opposing moments about both hip and knee joints, but by doing so perform the independent yet complementary roles of work avoidance during translating weight support and economical work supply.

Comparative Analysis of Muscle Activity and Circulatory Dynamics: A Crossover Study Using Leg Exercise Apparatus and Ergometer.

Background and Objectives: Bedridden patients are at a high risk of venous thromboembolism (VTE). Passive devices such as elastic compression stockings and intermittent pneumatic compression are common. Leg exercise apparatus (LEX) is an active device designed to prevent VTE by effectively contracting the soleus muscle and is therefore expected to be effective in preventing disuse of the lower limbs. However, few studies have been conducted on the kinematic properties of LEX. Therefore, this study aimed to compare the exercise characteristics of LEX with those of an ergometer, which is commonly used as a lower-limb exercise device, and examine its effect on the two domains of muscle activity and circulatory dynamics. Materials and Methods: This study used a crossover design in which each participant performed both exercises to evaluate the exercise characteristics of each device. Fifteen healthy adults performed exercises with LEX and an ergometer (Terasu Erugo, SDG Co., Ltd., Tokyo, Japan) for 5 min each and rested for 10 min after each exercise. Muscle activity was measured using surface electromyography (Clinical DTS, Noraxon, Scottsdale, AZ, USA), and circulatory dynamics were recorded using a non-invasive impedance cardiac output meter (Physioflow Enduro, Manatec Biomedical, Paris, France). The primary outcome was the mean percentage of maximum voluntary contraction (%MVC) of the soleus muscle during exercise. Results: The mean %MVC of the soleus muscle was significantly higher in the LEX group, whereas no significant differences were observed across the periods and sequences. Heart rate, stroke volume, and cardiac output increased during exercise and decreased thereafter; however, the differences between the devices were not significant. Conclusions: LEX may not only have a higher thromboprophylaxis effect, but also a higher effect on preventing muscle atrophy as a lower-extremity exercise device. Additionally, LEX could potentially be used safely in patients who need to be monitored for changes in circulatory dynamics.

Comparison of accuracy and speed between plaster casting, high-cost and low-cost 3D scanners to capture foot, ankle and lower leg morphology of children requiring ankle-foot orthoses.

BACKGROUND: Traditional plaster-cast fabrication of an ankle-foot orthosis (AFO), although robust, is time-consuming and cumbersome. 3D scanning is quickly gaining attention as an alternative to plaster casting the foot and ankle region for AFO fabrication. The aim of this study was to assess the accuracy and speed of two high-performing 3D scanners compared with plaster casting in pediatric patients requiring an AFO. METHODS: Ten participants (mean age 10.0 ± 3.9 years) prescribed AFOs for a movement disorder were 3D scanned with the high-cost Artec Eva (Eva) and low-cost Structure Sensor II (SSII) using one-person (1p) and two-person (2p) protocols. Accuracy and speed for both 3D scanners were compared with corresponding plaster cast measures (≤5% acceptable difference). Bland and Altman plots were generated to show mean bias and limits of agreement. RESULTS: Overall, Eva and SSII were accurate for foot, ankle, and lower leg key clinical landmarks (Eva-1p: 4.4 ± 7.3%; Eva-2p: 3.2 ± 7.5%; SSII-1p: 0.6 ± 7.4%; SSII-2p: 0.7 ± 8.2%). Bland and Altman plots for the SSII demonstrated lower biases for 1p (bias 0.5 mm, LoA: -12.4-13.5 mm) and 2p (0.4 mm, LoA: -11.4-12.2 mm) protocols compared with Eva for 1p (bias 2.3 mm, LoA: -8.0-12.7 mm) and 2p (1.8 mm, LoA: -10.7-14.3 mm) protocols. The SSII 2p protocol was the fastest 3D scanning method (26.4 ± 11.1 s). CONCLUSIONS: The high-cost Eva and low-cost SSII 3D scanners using the 1p and 2p protocols produced comparable accuracy and faster capture of key clinical landmarks compared with plaster cast measures for the fabrication of AFOs in pediatric patients.

Combining robotics and functional electrical stimulation for assist-as-needed support of leg movements in stroke patients: A feasibility study.

PURPOSE: Rehabilitation technology can be used to provide intensive training in the early phases after stroke. The current study aims to assess the feasibility of combining robotics and functional electrical stimulation (FES), with an assist-as-needed approach to support actively-initiated leg movements in (sub-)acute stroke patients. METHOD: Nine subacute stroke patients performed repetitions of ankle dorsiflexion and/or knee extension movements, with and without assistance. The assist-as-needed algorithm determined the amount and type of support needed per repetition. The number of repetitions and range of motion with and without assistance were compared with descriptive statistics. Fatigue scores were obtained using the visual analogue scale (score 0-10). RESULTS: Support was required in 44 % of the repetitions for ankle dorsiflexion and in 5 % of the repetitions of knee extension, The median fatigue score was 2.0 (IQR: 0.2) and 4.0 (IQR: 1.5) for knee and ankle, respectively, indicating mild to moderate perceived fatigue. CONCLUSION: This study demonstrated the feasibility of assist-as-needed assistance through combined robotic and FES support of leg movements in stroke patients. It proved particularly useful for ankle dorsiflexion. Future research should focus on implementing this approach in a clinical setting, to assess clinical applicability and potential effects on leg function.

Infection of Mycoplasma hominis in the left lower leg amputation wound of a patient with diabetes: a case report.

BACKGROUND: Mycoplasma hominis is typically found on the mucosal epithelium of the human genital tract, with infections being rare. However, when the mucosal barrier is compromised or in individuals with weakened immune systems, this microorganism can trigger infections in both intragenital and extragenital sites. This study offers a comprehensive overview of infections caused by the rare pathogen M. hominis. This overview helps laboratories identify M. hominis infections in a timely manner, thereby enabling earlier clinical intervention for patients. CASE PRESENTATION: A 75-year-old Taiwanese man with type 2 diabetes mellitus initially underwent a left lower extremity amputation following a severe infection caused by necrotizing fasciitis. Subsequently, a poorly healing wound developed at the site of amputation. Upon culturing the wound abscess, M. hominis was isolated and identified as the causative agent. CONCLUSIONS: Through this case, we present clinical and microbiological observations along with a review of the literature to deepen our understanding of M. hominis. Our findings can be used to develop laboratory diagnostic protocols and innovative therapeutic approaches.

Benefits of home-based foot neuromuscular electrical stimulation on self-reported function, leg pain and other leg symptoms among community-dwelling older adults: a sham-controlled randomised clinical trial.

INTRODUCTION: Lower leg pain and symptoms, and poor leg circulation are common in older adults. These can significantly affect their function and quality of life. Neuromuscular electrical stimulation (NMES) applied via the feet as 'foot NMES' activates the leg musculovenous pump. This study investigated the effects of foot NMES administered at home using Revitive® among community-dwelling older adults with lower leg pain and/or other lower leg symptoms such as cramps, or sensations of tired, aching, and heavy feeling legs. METHODS: A randomised placebo-controlled study with three groups (2 NMES, 1 Sham) and three assessments (baseline, week 8, week 12 follow-up) was carried out. Self-reported function using Canadian occupational performance measure (COPM), leg pain, overall leg symptoms score (heaviness, tiredness, aching, or cramps), and ankle blood flow were assessed. Analysis of covariance (ANCOVA) and logistic regression were used to compare the groups. Statistical significance was set at p < 0.05 (two-sided 5%). RESULTS: Out of 129 participants enrolled, 114 completed the study. The improvement in all outcomes were statistically significant for the NMES interventions compared to Sham at both week 8 (p < 0.01) and week 12 (p < 0.05). The improvement in COPM met the minimal clinically important difference (MCID) for the NMES interventions compared to Sham at both week 8 (p < 0.005) and week 12 (p < 0.05). Improvement in leg pain met MCID at week 8 compared to Sham (p < 0.05). Ankle blood flow increased approximately 3-fold during treatment compared to Sham. Compliance with the interventions was high and no device-related adverse events were reported. CONCLUSIONS: The home-based foot NMES is safe, and significantly improved self-reported function, leg pain and overall leg symptoms, and increased ankle blood flow compared to a Sham among older adults. TRIAL REGISTRATION: The trial was prospectively registered in ISRCTN on 17/06/2019 with registration number ISRCTN10576209. It can be accessed at https://www.isrctn.com/ISRCTN10576209 .

Associating neuromotor outcomes at 12 months with wearable sensor measures collected during early infancy in rural Guatemala.

BACKGROUND: Sensitive measures to predict neuromotor outcomes from data collected early in infancy are lacking. Measures derived from the recordings of infant movement using wearable sensors may be a useful new technique. METHODS: We collected full-day leg movement of 41 infants in rural Guatemala across 3 visits between birth and 6 months of age using wearable sensors. Average leg movement rate and fuzzy entropy, a measure to describe the complexity of signals, of the leg movements' peak acceleration time series and the time series itself were derived. We tested the three measures for the predictability of infants' developmental outcome, Bayley Scales of Infant and Toddler Development III motor, language, or cognitive composite score assessed at 12 months of age. We performed quantile regressions with clustered standard errors, accounting for the multiple visits for each infant. RESULTS: Fuzzy entropy was associated with the motor composite score at the 0.5 quantiles; this association was not found for the other two measures. Also, no leg movement characteristic was associated with language or cognitive composite scores. CONCLUSION: We propose that the entropy of leg movement associated peak accelerations calculated from the wearable sensor data collected for a full-day can be considered as one predictor for infants' motor developmental outcome assessed with Bayley Scales of Infant and Toddler Development III at 12 months of age.

In vitro and in vivo optimized reconstruction for low-keV virtual monoenergetic photon-counting detector CT angiography of lower legs.

BACKGROUND: Lower extremity peripheral artery disease frequently presents with calcifications which reduces the accuracy of computed tomography (CT) angiography, especially below-the-knee. Photon-counting detector (PCD)-CT offers improved spatial resolution and less calcium blooming. We aimed to identify the optimal reconstruction parameters for PCD-CT angiography of the lower legs. METHODS: Tubes with different diameters (1-5 mm) were filled with different iodine concentrations and scanned in a water container. Images were reconstructed with 0.4 mm isotropic resolution using a quantitative kernel at all available sharpness levels (Qr36 to Qr76) and using different levels of quantum iterative reconstruction (QIR-2-4). Noise and image sharpness were determined for all reconstructions. Additionally, CT angiograms of 20 patients, reconstructed with a medium (Qr44), sharp (Qr60), and ultrasharp (Qr72) kernel at QIR-2-4, were evaluated by three readers assessing noise, delineation of plaques and vessel walls, and overall quality. RESULTS: In the phantom study, increased kernel sharpness led to higher image noise (e.g., 16, 38, 77 HU for Qr44, Qr60, Qr72, and QIR-3). Image sharpness increased with increasing kernel sharpness, reaching a plateau at the medium-high level 60. Higher QIR levels decreased image noise (e.g., 51, 38, 25 HU at QIR-2-4 and Qr60) without reducing vessel sharpness. The qualitative in vivo results confirmed these findings: the sharp kernel (Qr60) with the highest QIR yielded the best overall quality. CONCLUSION: The combination of a sharpness level optimized reconstruction kernel (Qr60) and the highest QIR level yield the best image quality for PCD-CT angiography of the lower legs when reconstructed at 0.4-mm resolution. RELEVANCE STATEMENT: Using high-resolution PCD-CT angiography with optimized reconstruction parameters might improve diagnostic accuracy and confidence in peripheral artery disease of the lower legs. KEY POINTS: Effective exploitation of the potential of PCD-CT angiography requires optimized reconstruction parameters. Too soft or too sharp reconstruction kernels reduce image quality. The highest level of quantum iterative reconstruction provides the best image quality.

Performance of calf circumference in identifying sarcopenia in older patients with chronic low back pain: a retrospective cross-sectional study.

BACKGROUND: Calf circumference is currently recommended as a case-finding marker for sarcopenia, but its usefulness has not been determined in chronic pain conditions. Therefore, the present study aimed to evaluate the predictive performance of calf circumference in diagnosing sarcopenia in older patients with chronic low back pain. METHODS: Ambulatory adult patients aged ≥ 65 years with chronic low back pain were enrolled. A diagnosis of sarcopenia was established based on the criteria outlined by the Asian Working Group for Sarcopenia in 2019. Patient demographics, pain-related factors, clinical factors, and sarcopenia-related measurements were compared between non-sarcopenic and sarcopenic patients. Linear regression analysis was used to evaluate the correlation of calf circumference with muscle mass, strength, and physical performance. Also, a receiver operating characteristic curve analysis for calf circumference in predicting sarcopenia was conducted; and area under the curve (AUC) values, along with their corresponding 95% confidence intervals (CI), were calculated. RESULTS: Data from 592 patients were included in the analysis. Eighty-five patients were diagnosed with sarcopenia (14.3%), 71 of whom had severe sarcopenia (11.9%). A higher prevalence of sarcopenia was observed in female patients (9.0% vs. 16.7%, p = 0.016). After adjusting for age, BMI, and comorbidities, calf circumference correlated positively with muscle mass but not with muscle strength and physical performance. The AUC values for sarcopenia were 0.754 (95% CI = 0.636-0.871, p = 0.001) in males and 0.721 (95% CI = 0.657-0.786, p < 0.001) in females. The cut-offs for calf circumference in predicting sarcopenia were 34 cm (sensitivity 67.1%, specificity 70.6%) in males, and 31 cm (sensitivity 82.5%, specificity 51.5%) in females. CONCLUSIONS: Even though sex differences in its predictive value for sarcopenia should be considered, our findings suggest that calf circumference can be used as an indicator for predicting muscle mass and may serve as a potential marker for identifying sarcopenia in older patients with chronic low back pain.

Effects of a passive upper-body exoskeleton on whole-body kinematics, leg muscle activity, and discomfort during a carrying task.

OBJECTIVE: To compare whole-body kinematics, leg muscle activity, and discomfort while performing a 10-min carrying task with and without a passive upper-body exoskeleton (CarrySuitⓇ), for both males and females. BACKGROUND: Diverse commercial passive exoskeletons have appeared on the market claiming to assist lifting or carrying task. However, evidence of their impact on kinematics, muscle activity, and discomfort while performing these tasks are necessary to determine their benefits and/or limitations. METHOD: Sixteen females and fourteen males carried a 15kg load with and without a passive exoskeleton during 10-min over a round trip route, in two non-consecutive days. Whole-body kinematics and leg muscle activity were evaluated for each condition. In addition, leg discomfort ratings were quantified before and immediately after the task. RESULTS: The gastrocnemius and vastus lateralis muscle activity remained constant over the task with the exoskeleton. Without the exoskeleton a small decrease of gastrocnemius median activation was observed regardless of sex, and a small increase in static vastus lateralis activation was observed only for females. Several differences in sagittal, frontal, and transverse movements' ranges of motion were found between conditions and over the task. With the exoskeleton, ROM in the sagittal plane increased over time for the right ankle and pelvis for both sexes, and knees for males only. Thorax ROMs in the three planes were higher for females only when using the exoskeleton. Leg discomfort was lower with the exoskeleton than without. CONCLUSION: The results revealed a positive impact on range of motion, leg muscle activity, and discomfort of the tested exoskeleton.