Search Results (68)

Aim: The present study aimed to evaluate the agreement between calf circumference (CC) and dual-energy X-ray absorptiometry (DEXA) in assessing muscle mass, and to determine how possible discrepancies influence the diagnosis of malnutrition and its relationship with frailty and disability in older adults. Methods: We analyzed cross-sectional data from 1048 adults aged 65 years and older who participated in the 2001–2002 National Health and Nutrition Examination Survey (NHANES). Malnutrition was defined using the Global Leadership Initiative on Malnutrition (GLIM) criteria, and muscle mass was estimated using both DEXA and CC. Agreement between the two assessment methods was tested with Kappa statistics, while multivariable logistic regression models were used to explore the associations between malnutrition (as determined by each method) and frailty or disability, controlling for age, sex, physical activity, polypharmacy, and urinary albumin levels. Results: CC and DEXA-based appendicular skeletal muscle mass (ASM) showed a moderate correlation (r = 0.592). The prevalence of malnutrition was 10.3% when defined by CC and 9.1% when defined by DEXA (κ = 0.635, p = 0.001). In both cases, malnutrition was significantly associated with frailty (OR: 1.56; 95% CI: 1.240, 1.970, p < 0.001), but not with disability. Adjusting for albumin levels did not substantially change these associations. Conclusions: CC and DEXA demonstrate moderate concordance in estimating ASM. While this level of agreement slightly affects malnutrition prevalence estimates, it does not alter the observed relationship between malnutrition and frailty or disability in older adults. Full article

Powered ankle exoskeletons have become efficient ability-enhancing and rehabilitation tools that support human body movements. Traditionally, the control schemes for ankle exoskeletons were implemented relying on precise physical and kinematic models. However, this approach resulted in poor coordination of human–machine coupled motion and an increase in the wearer’s energy consumption. To solve the cooperative control issue between the wearer and the ankle exoskeleton, this work introduces an adaptive impedance control method for the ankle exoskeleton that is based on the surface electromyography (sEMG) of the calf muscles. The proposed method achieves cooperative control by leveraging an experience-based fuzzy rule interpolation (E-FRI) approach to dynamically adjust the impedance model parameters. This adaptive mechanism is driven by the wearer’s calf sEMG signals, which capture the wearer’s movement state. The adaptive impedance model then computes the desired torque for the ankle exoskeleton. To validate and evaluate the system, the control method was implemented on a simplified ankle exoskeleton. Experimental validation with five healthy participants (age 19 ± 1.35 years) demonstrated significant improvements over conventional fixed-impedance approaches: mean RMS reductions of 19.7% in gastrocnemius activation and 21.4% in soleus activation during treadmill walking. This study establish a new paradigm for responsive exoskeleton control through symbiotic integration of neuromuscular signals and adaptive fuzzy inference, offering critical implications for rehabilitation robotics and assistive mobility technologies. Full article

Chronic venous insufficiency (CVI) is a common peripheral vascular condition characterised by the retrograde blood flow in the lower extremities and its consequences such as oedema and other complications. Clinical severity of CVI is assessed according to the CEAP (Clinical, Etiological, Anatomic, and Physiopathologic) classification, which recognises seven grades of increasing clinical severity (C₀–C₆). Compression therapy aims to accelerate vein, lymph, and microcirculation flow and therefore reduce chronic nonbacterial inflammation and oedema of the extremities. In accordance with the elasticity and stiffness, compression bandages and garments are divided into short-stretch and long-stretch compression materials. Compression therapy is applicable in all stages of CVI. Moreover, compression therapy in conjunction with physical therapy and lifestyle modifications is more effective in reducing oedema, preventing venous distension, and reducing venous wall tension, all while improving calf muscle pump function. Physical therapy in CVI treatment combines everyday lifestyle modifications, physical activity, medical exercise, sports activity, hydrotherapy, and electrotherapy. Therefore, physical therapy is used either for prevention or either for therapeutic purposes in CVI. For grades CEAP C₀–C_2, preventive measures consist of education and counselling, medical exercise and general fitness, and sports and physical activities. However, for therapy in grades CEAP C₃–C₆, medical exercise and a specific rehabilitation programme, manual lymphatic drainage and massage, balneotherapy, and electrotherapy are recommended. Full article

Background/Objectives: Parkinson’s disease (PD) is a progressive neurodegenerative disorder characterized by motor symptoms such as tremor, bradykinesia, rigidity, and postural instability. In the absence of disease-modifying therapies, exercise remains one of the few interventions shown to effectively reduce fall risk and improve mobility. However, it remains unclear whether skeletal muscle ATP metabolism is impaired in PD, and whether the benefits of exercise arise primarily from improvements in central motor control or peripheral metabolic adaptations. Methods: Fourteen individuals with PD and five healthy controls underwent kinetic ³¹P Magnetic Resonance Spectroscopy (MRS) to assess resting muscle ATP synthesis and dynamic ³¹P MRS during in-magnet exercise to evaluate oxidative phosphorylation in active muscle. Results: At rest, ATP synthesis rates mediated by ATPase and creatine kinase (CK) were on average 46 ± 23% and 24 ± 9% lower, respectively, in the PD group compared to controls (p < 0.005), suggesting peripheral mitochondrial dysfunction. During plantar flexion exercise at 15% of lean body mass, range of motion (ROM) was reduced by 22 ± 5% in PD participants (p = 0.01). Despite this, post-exercise recovery of phosphocreatine (PCr) and inorganic phosphate (Pi) was similar between groups. Recovery time constants for PCr and Pi correlated with participants’ total weekly exercise time, indicating a metabolic adaptation to regular physical activity. Modest ROM improvements were observed in both groups following calf-raise exercise training. Conclusions: Reduced skeletal muscle ATP metabolism may contribute to peripheral weakness in PD. Regular exercise appears to promote adaptive metabolic responses, highlighting the need for therapeutic strategies targeting both central and peripheral components of PD. Full article

Background: Sarcopenia is a critical complication in hemodialysis patients, associated with poor clinical outcomes, increased morbidity, and reduced quality of life. Despite this, its significance, prevalence, and risk factor data in developing countries remain limited. Objective: This study aimed to determine the prevalence of sarcopenia and identify its independent risk factors in patients undergoing maintenance hemodialysis, while evaluating its impact on physical performance, nutritional intake, and quality of life. Methods: A multicenter cross-sectional study was conducted across three hemodialysis units in Tunisia. Sarcopenia was diagnosed using EWGSOP2 (European Working Group on Sarcopenia in Older People 2) criteria based on muscle strength, muscle mass, and physical performance. Handgrip dynamometry, mid-arm and calf circumferences, gait speed, Short Physical Performance Battery (SPPB), and Timed Up and Go (TUG) test were employed. Nutritional intake was assessed using a 7-day food history. Quality of life and functional status were evaluated using the SF-36 and Barthel Index, respectively. Logistic regression was used to identify independent predictors of sarcopenia. Results: Among 118 patients (mean age 56.74 ± 14.44 years), the prevalence of sarcopenia was 42.4% (n = 50). Sarcopenic individuals exhibited significantly poorer physical performance than their non-sarcopenic counterparts. Marked reductions were observed in handgrip strength (p < 0.001, d = −1.60, very large), SPPB scores (p < 0.001, d = −1.55, very large), and increased TUG time (p < 0.001, d = 1.46, very large), indicating substantial functional impairment. Limb circumferences were also significantly lower in the sarcopenic group, including calf circumference (p = 0.002, d = −1.39, large) and mid-arm circumference (p = 0.013, d = −0.87, large). Gait speed was slower (p = 0.010, d = −0.40, small to moderate). Health-related quality of life was significantly compromised in sarcopenic individuals, with lower SF-36 total scores (p = 0.001, d = −1.96, very large) and reduced functional independence as measured by the Barthel Index (p = 0.010, d = −0.97, large). Hemoglobin levels were also significantly lower in the sarcopenic group (p = 0.048, d = −0.96, large). Dietary assessment revealed lower fiber intake (p = 0.006, d = 1.80, very large) and reduced magnesium consumption (p = 0.020, d = 0.94, large) among individuals with sarcopenia. In the multivariate logistic regression analysis, diabetes mellitus (OR = 2.14, 95% CI: 1.30–3.67, p < 0.001) and longer duration of hemodialysis (OR = 1.56, 95% CI: 1.20–2.71, p = 0.028) were identified as independent predictors of sarcopenia. A lower SPPB score (OR = 0.48, 95% CI: 0.35–0.65, p < 0.001) was associated with sarcopenia. Conclusion: Sarcopenia is highly common among hemodialysis patients and is independently linked to diabetes, treatment duration, and reduced physical performance. It significantly affects the quality of life and ability to perform daily activities. Routine screening with simple functional tests is crucial, especially in high-risk patients. Early intervention should include physical rehabilitation, nutritional support, and strict blood sugar management to decrease sarcopenia-related complications. Full article

Background/Objectives: Vitamin D deficiency is linked to muscle loss and fat changes in older adults, but data regarding palliative patients are limited. Ultrasound offers a practical tool to assess these changes. This study explores the relationship between vitamin D levels and ultrasound-measured muscle, fat, and their ratio in older adult palliative patients. Methods: This prospective cross-sectional study was conducted in a tertiary palliative care unit (June–September 2024). A total of 187 patients were grouped by serum vitamin D levels (<50 vs. ≥50 nmol/L). Demographic and clinical variables included sex, BMI, Activities of Daily Living (ADLs), calf circumference (CC), and comorbidities. Ultrasonography assessed muscle thickness (MT), subcutaneous fat thickness (SFT), and cross-sectional area (CSA) of Rectus Femoris (RF) and Biceps Brachii (BB). MT/SFT ratio was calculated. Logistic regression identified independent predictors. Results: Mean age was 75.1 ± 14.4 years; 55.6% of participants were female. Vitamin D deficiency (67.9%) was significantly associated with female sex (p = 0.037), ADL dependency (p < 0.001), lower BMI (p = 0.020), and reduced CC (p = 0.006). RF-MT, RF-SFT, RF-CSA, BB-MT, and BB-CSA were lower in the deficient group. RF-MT/SFT ratio was higher (p = 0.049). ADL dependency (p = 0.002) and RF-MT/SFT (p = 0.015) were independent predictors. Conclusions: Vitamin D deficiency was linked to a higher muscle-to-fat ratio, mainly due to fat loss rather than muscle gain. This may misrepresent muscle preservation and should be interpreted cautiously. Although vitamin D levels appear to be associated with physical function, additional prospective cohort and interventional supplementation studies are warranted to determine whether routine screening and targeted vitamin D supplementation can effectively support physical function in this population. Full article

Background: The medial (MG) and lateral gastrocnemius (LG) muscles exhibit differential activation patterns during plantar flexion tasks. However, the influence of range of motion (ROM), exercise type (unilateral vs. bilateral), and limb dominance on muscle activity during heel raise exercises (HREs) remains unclear. Methods: Nineteen physically active adults performed unilateral and bilateral HREs under two ankle ROM conditions: neutral (NROM) and full (FROM). Surface electromyography (EMG) was collected from both legs during each condition and normalized to peak values recorded during overground sprinting. Results: MG activity was significantly higher during the FROM than the NROM, in both the dominant leg (F = 11.55, p < 0.01, η² = 0.47) and the non-dominant leg (F = 6.63, p < 0.05, η² = 0.31), and was not affected by exercise type. In contrast, LG activity increased significantly during unilateral versus bilateral HREs, especially in the dominant leg during the FROM (F = 17.47, p < 0.01, η² = 0.52) and in the non-dominant leg (F = 5.44, p < 0.05, η² = 0.25). Activation ratios (MG:LG) differed significantly between dominant and non-dominant legs only in the unilateral FROM (p = 0.03). MG activation during the unilateral FROM was comparable to sprinting values, highlighting its high neuromuscular demand. Conclusion: The MG and LG respond differently to exercise parameters. The MG is primarily influenced by ROM, whereas the LG is sensitive to both exercise type and limb dominance. These findings emphasize the importance of ROM manipulation and unilateral training to target specific gastrocnemius regions. FROM and unilateral execution optimize gastrocnemius activation, with implications for rehabilitation and performance programs targeting calf musculature. Full article

Background: There is no cure for mitochondrial diseases which manifest in numerous ways including fatigue, muscle weakness, and exercise intolerance. Medical treatment varies and focuses on managing symptoms. Photobiomodulation (PBM) can decrease mitochondrial damage thereby increasing energy production and decreasing cell death. This pilot study will apply PBM to people with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) to examine the safety of application, and if changes occur in symptoms and signs after cross-over application/withdrawal of a sham or active PBM treatment including a two-week period of washout. Methods: This study is an exploratory, prospective series N-of-1 (single patient) studies. The protocol is guided by the CONSORT extension for reporting N-of-1 trials (CENT 2015), chosen due to the rarity of mitochondrial diseases, the fluctuating symptomology, and heterogeneity of the clinical presentation. The primary outcome is patient-reported fatigue assessed using the Checklist of Individual Strength and with concomitant evaluation of safety. Secondary measures are of depression, anxiety and stress, sleepiness, physical activity, blood lactate and creatine kinase, physical measures of sit-to-stand, and heel raise capability. Mitochondrial function will be evaluated using hydrogen magnetic resonance spectroscopy for lactate. PBM will be a participant-administered, home-based therapy using a multiple diode flexible array (BeniLight iLED-Pro Multi-Wave Multi-Pulse belt; 465 nm, 660 nm, 850 nm; average irradiance 5.23 mW/cm²; total joules: 770.1 J/treatment, all sites; 5 KHz; 20% duty ratio) over the anterior thigh muscles, posterior calf muscles and abdomen for 10 min to each site, three times/week. The safety of the intervention will be assessed. Descriptive statistics, causal analyses of time series data and dynamic modelling will be applied as relevant to the variables collected. Hydrogen magnetic resonance spectra will be acquired and averaged to obtain the content of the targeted hydrogen levels. Discussion: The study will provide guidance on whether and how to progress to a larger, randomised cohort study with sham control. Full article

Injuries to the soleus muscle are often unrecognized, which increases the risk of complete tearing. Consequently, it results in the need for a long break in sports. This is mainly because the soleus muscle is complex, and the clinical signs of injury are difficult to capture, which can mimic Achilles tendinopathy and tennis player’s calves. This muscle has a complex connective tissue structure with three intramuscular tendons, which makes it challenging to interpret pathological muscle conditions. Injuries to the soleus muscle can be acute or chronic and are usually considered to be a minor discomfort by both the patient and the sports medicine physician, leading to a relatively quick return to sports activity with a high risk of re-injury. This narrative literature review aims to explore the diagnostic challenges and treatment failures associated with soleus muscle injuries, highlighting the critical lack of standardized protocols and a comprehensive understanding of the nuances of these injuries, which requires the collection of qualitative data from clinical case studies, quantitative data from imaging studies and rehabilitation outcomes, and expert opinion to formulate evidence-based guidelines to improve patient management. Calf muscle pain symptoms should not be ignored because the injury may become chronic, and the lack of treatment adequate to the actual cause of the pain increases the risk of the injury deepening, including complete rupture. High-resolution ultrasonography and magnetic resonance imaging are recommended methods for differentially diagnosing soleus muscle injury in conjunction with physical examination to make a precise and reliable diagnosis. A soleus muscle injury case report and a comprehensive proposal for conservative treatment supplement our literature review. Full article

Fatigue causes the lower limb to land in an injury-prone state, but the underlying neuromuscular control changes remain unclear. This study aims to investigate lower limb muscle synergies during landing in basketball players, both before and after fatigue, to examine alterations in neuromuscular control strategies induced by fatigue. Eighteen male recreational basketball players performed landing tasks pre- and post-fatigue induced by 10 × 10 countermovement jumps. Electromyographic (EMG) data from eight muscles, including the erector spinae (ES), rectus abdominus (RA), gluteus maximus (GM), rectus femoris (RF), biceps femoris (BF), lateral gastrocnemius (LG), soleus (SM), and tibialis anterior (TA) muscles, were analyzed using non-negative matrix factorization to extract muscle synergies. Post-fatigue results revealed significant changes: synergy primitive 1 decreased before landing (18–30% phase) and synergy primitive 2 decreased after landing (60–100% phase). Muscle weights of the LG and SM in synergy module 2 increased. Fatigue reduced synergistic muscle activation levels, compromising joint stability and increasing knee joint loading due to greater reliance on calf muscles. These changes heighten the risk of lower limb injuries. To mitigate fatigue-induced injury risks, athletes should improve thigh muscle endurance and enhance neuromuscular control, fostering better synergy between thigh and calf muscles during fatigued conditions. Full article

High-level (HL) and low-level (LL) competitive aerobics athletes demonstrate different landing patterns during rotational jump landings, resulting in differing risks of lower limb injuries. This research aimed to investigate biomechanical differences between different levels of competitive aerobics athletes during rotational jump landings. The subjects included 15 male HL athletes and 15 LL athletes. This study captured kinematics, kinetics, muscle activation, and muscle force data, calculating joint stiffness, energy dissipation, anterior tibial shear force (ATSF), and patellofemoral joint contact force (PTF). LL athletes demonstrated significantly greater ankle dorsiflexion, inversion, and internal rotation angles; knee abduction angle and moment, internal rotation angle and moment; and smaller ankle plantarflexion moment and knee flexion angle. They also showed lower calf muscle coactivation, PTF, joint stiffness at the knee and hip, and the energy dissipation of the ankle and lower limb; greater thigh muscle coactivation and ATSF. The results show that LL athletes exhibit poorer stability at the ankle and knee joints, with a higher risk of anterior cruciate ligament (ACL) and ankle inversion injuries during rotational jump landings. To lower these risks, LL athletes should increase the flexion angle of the knee, hip, and ankle plantarflexion during landing. Full article

Background/Objectives: The aim of the present study was to assess the effectiveness of flexibility or strengthening exercises to improve flexibility, strength, muscle architecture, and functional performance in older adults with leg tightness and/or suspected sarcopenia. Methods: Ninety adults with leg tightness and/or suspected sarcopenia (age: 66.8 ± 4.9 years) were randomly allocated to two subtypes of intervention at home: resistance-band exercise (RE) or eccentric exercise (ECC) for those with weakness; static or dynamic stretching for those with tightness; and static stretching plus ECC or no exercise for those with both muscle tightness and weakness. The program consisted of 3–6 weekly sessions over eight weeks. Blinded outcome assessments before and after the eight-week program and at the three-month follow-up included mobility performance via Timed Up-and-Go (TUG), and flexibility and strength tests, as well as measurement of stiffness. Results: All groups had increased peak torque after eight weeks and improved TUG at the three-month follow-up (p < 0.05). Improved plantar flexor strength persisted at the three-month follow-up (p = 0.009). In addition, the RE and ECC groups had increased muscle thickness by 4.0 and 8.7% after eight weeks (p < 0.05). Hamstring flexibility increased in all exercise groups, except the RE group. Moreover, all six groups showed improved calf flexibility, whereas no changes in stiffness were noted. Conclusions: Increases in mobility performance, strength, and flexibility appeared due to learning effects and increased physical activity, rather than the specific training impact. However, strength-based programs may be recommended for older adults with suspected sarcopenia, as they provide additional benefits, such as short-lasting muscle hypertrophy. Full article

Background: Achilles tendon rupture rehabilitation protocols often emphasize two key factors, namely plantar flexion and load restriction during the early recovery stages. However, we hypothesize that variations in walking speed also play a significant role in affecting the load on the Achilles tendon. This study aims to explore the combined impact of plantar flexion angle and walking speed on the surface electromyography (EMG) activity of the calf muscles. Methods: Surface EMG measurements on 24 healthy volunteers assessed the activity of the calf muscles (gastrocnemius lateralis, gastrocnemius medialis, and soleus). Participants walked on a treadmill using two designs of ankle foot orthoses set at three different angles of the ankle joint (mainly 0°, 15°, or 30° plantar flexion), as well as barefoot and in sports shoes. The tests were performed at full loads of 1, 2 and 4 km/h or with additional measurements at 1 and 2 km/h with a partial load of 20 kg. The walking speed of 4 km/h in sports shoes was used as reference, corresponding to the maximum load on the calf muscles during walking. Results: Both orthoses demonstrated a significant reduction in EMG activity by more than half even at a 0° setting and 1 km/h compared to walking barefoot or in sports shoes. However, as walking speed increased to 2 km/h and especially to 4 km/h, EMG activity significantly increased, approaching the level of walking with sports shoes at 1 km/h. The results indicated that even minor changes in walking speed had a significant impact on muscle activity, underscoring the importance of this parameter. Conclusions: This study suggests that walking speed should be considered a crucial factor in rehabilitation protocols for Achilles tendon ruptures, alongside plantar flexion and load restrictions, to optimize recovery outcomes. Full article

Background: Advanced footwear technology (AFT) has gained popularity among non-elite runners due to its potential benefits in training and competition. This study investigated the training practices and reported outcomes in non-elite runners using AFT. Methods: A cross-sectional observational study was conducted with 61 non-elite runners competing in distances ranging from 5 km to marathons. The survey collected data on demographics, training parameters, footwear usage, perceived changes in running mechanics, and self-reported injuries. Results: The results revealed a significant positive correlation (R = 0.6, p < 0.0001) between years of AFT use and weekly training volume, indicating that more experienced runners are likely to incorporate AFT consistently into their routines. Conversely, a significant negative correlation (R = −0.5, p < 0.0001) was found between training volume and the number of weekly sessions using AFT, suggesting a selective approach to footwear use. Participants reported biomechanical changes, such as increased forefoot support (49%) and higher calf muscle activation (44%), alongside a 16% self-reported injury rate, predominantly affecting the calves. Conclusions: These findings highlight the importance of proper guidance and gradual adaptation to maximize the benefits of AFT while minimizing injury risks. Future research should explore the long-term impact of AFT on performance and injury prevention through longitudinal studies. Full article

Freezing of gait (FOG) is a disabling yet poorly understood paroxysmal gait disorder affecting the vast majority of patients with Parkinson’s disease (PD) as they reach advanced stages of the disorder. Falling is one of the most disabling consequences of a FOG episode; it often results in injury and a future fear of falling, leading to diminished social engagement, a reduction in general fitness, loss of independence, and degradation of overall quality of life. Currently, there is no robust or reliable treatment against FOG in PD. In the absence of reliable and effective treatment for Parkinson’s disease, alleviating the consequences of FOG represents an unmet clinical need, with the first step being reliable FOG prediction. Current methods for FOG prediction and prevention cannot provide real-time readouts and are not sensitive enough to detect changes in walking patterns or balance. To fill this gap, we developed an sEMG system consisting of a soft, wearable garment (pair of shorts and two calf sleeves) embedded with screen-printed electrodes and stretchable traces capable of picking up and recording the electromyography activities from lower limb muscles. Here, we report on the testing of these garments in healthy individuals and in patients with PD FOG. The preliminary testing produced an initial time-to-onset commencement that persisted > 3 s across all patients, resulting in a nearly 3-fold drop in sEMG activity. We believe that these initial studies serve as a solid foundation for further development of smart digital textiles with integrated bio and chemical sensors that will provide AI-enabled, medically oriented data. Full article