Search Results (944)

Background: Sarcopenia and low muscle mass are prevalent and prognostically relevant in patients with lung cancer, yet their diagnosis remains challenging in routine clinical practice. Opportunistic assessment using computed tomography (CT) has emerged as a valuable tool for body composition evaluation. We aimed to assess the utility of thoracic CT at T12 and T4 levels in identifying sarcopenia and low muscle mass and explore their correlation with morphofunctional tools such as bioelectrical impedance vector analysis (BIVA), nutritional ultrasound (NU), and functional performance tests. Methods: In this prospective observational study, 80 patients with lung cancer were evaluated at diagnosis. Body composition was assessed using BIVA-, NU-, and CT-derived parameters at T12 and T4 levels. Functional status was measured using the Timed Up and Go (TUG) and 30-Second Chair Stand Test. Sarcopenia was defined according to EWGSOP2 criteria. Results: Sarcopenia was identified in 20% of patients. CT-derived indices at T12CT demonstrated better diagnostic performance than T4CT. For detecting low muscle mass, the optimal SMI cut-off values were SMI_T12CT < 31.98 cm²/m² and SMI_T4CT < 59.05 cm²/m² in men and SMI_T12CT < 28.23 cm²/m² and SMI_T4CT < 41.69 cm²/m² in women. For sarcopenia diagnosis, the values were SMI_T12CT < 24.78 cm²/m² and SMI_T4CT < 57.23 cm²/m² in men and SMI_T12CT < 21.24 cm²/m² and SMI_T4CT < 49.35 cm²/m² in women. A combined model including SMI_T12CT, RF_CSA, and the 30 s squat test showed high diagnostic accuracy (AUC = 0.826). In multivariable analysis, lower SMA_T12CT was independently associated with risk of sarcopenia (OR = 0.96, 95% CI: 0.92–0.99, p = 0.022), as were older age (OR = 1.23, 95% CI: 1.07–1.47, p = 0.010) and fewer repetitions in the 30 s squat test (OR = 0.78, 95% CI: 0.63–0.91, p = 0.007). Conclusions: CT-derived body composition assessment, particularly at the T12 level, shows good correlation with morphofunctional tools and may offer a reliable and timely alternative for identifying sarcopenia and low muscle mass in patients with lung cancer. Full article

CrossFit performance is influenced by physiological, neuromuscular, and perceptual factors, yet the extent to which these determinants vary by sex or training experience in standardized CrossFit Workouts of the Day (WODs) remains unclear. This study examined whether variables such as lactate accumulation, oxygen uptake dynamics, jump performance loss, and ventilatory responses relate differently to performance when stratified by sex and expertise. Fifteen trained athletes (eight males, seven females; overall mean age 27.7 ± 4.6 years) took part. Assessments included body composition, squat (SJ) and countermovement jumps (CMJ), and maximal oxygen consumption [VO₂max]. On a separate day, they performed Fran (21-15-9 thrusters and pull-ups, Rx or scaled) The prescribed (‘Rx’) version used standardized barbell loads (43 kg for men, 29 kg for women), while the scaled version involved reduced loads or pull-up modifications. Respiratory gas exchange and heart rate were continuously monitored, while blood lactate and jump performance were measured pre- and post-WOD. Workout completion time [s] was the primary outcome. Correlation heatmaps explored associations in the overall sample and by sex and expertise. Mean completion time was 422.1 ± 173.2 s (range: 200–840). Faster performance correlated with higher ventilatory responses [ΔVe, r = −0.60, p = 0.018], greater mean VO₂ (r = −0.62, p = 0.014), superior jump power [CMJ pre, r = −0.65, p = 0.009], and higher post-WOD lactate [r = −0.54, p = 0.036]. Sex-stratified analyses showed that males relied on ventilatory efficiency and neuromuscular power, whereas females were more constrained by performance loss and higher resting perceived exertion (RPE). Experts depended on ventilatory and neuromuscular efficiency, while initiates showed stronger associations with decrements in jump performance and higher RPE. These findings highlight subgroup-specific performance profiles and reinforce the need for tailored training strategies in CrossFit athletes. Full article

Introduction: Nowadays, there is evidence regarding a beneficial effect of heat on neuromuscular strength and muscle hypertrophy development. The aim of this study is to evaluate the effects of a 4-week passive sauna bathing program to extreme heat (100 ± 2 °C) as a support for a resistance strength training program on maximal strength and body composition. Methods: 30 young male subjects participated in the study. They were randomly assigned to a Hyperthermia group (HG, n = 14; age: 20.48 (19.12–22–30) years; weight: 76.30 (71.00–79.00) Kg; BMI: 23.92 (22.93–24.87) Kg/m²), or to a Normothermia group (NG, n = 15; age: 19.95 (19.10–21–94) years; weight: 61.70 (59.45–72.90) Kg; BMI: 21.56 (20.42–23.26) Kg/m²). All participants followed the same lower limb strength training program (2 exercises; 4 sets of 10 repetitions at 75% 1RM with progressive loading). Additionally, HG underwent two weekly sessions of exposure to extreme heat in a sauna (100 ± 2 °C and 24 ± 1% relative humidity, four sets of 10 min, 2 days per week). The intervention lasted for 4 weeks, followed by a 4-week deconditioning period. Maximum isometric knee flexion-extension strength, maximum counter-resistance strength, as well as body composition and anthropometric variables were assessed. Results: The HG group significantly increased body weight (p < 0.05) and muscle mass (p < 0.05), while their sum of six skinfolds (Σ6 skinfolds) significantly decreased (p < 0.05). Both groups improved their 1RM squat performance following the intervention program (p < 0.05; HG: r = 0.86; NG: r = 0.89). However, only the HG group continued to improve their squat 1RM after the deconditioning period (p < 0.001; r = 0.93), as well as their leg press 1RM (p < 0.01; r = 0.94). Maximal isometric strength increased only in the NG group at the end of the training program, with a significant increase in knee flexion torque (p < 0.05; r = 0.76). In contrast, the HG group showed significant increases in isometric strength after the deconditioning period in both knee extension (p < 0.05; r = 0.76) and knee flexion (p < 0.05; r = 0.75). Conclusions: A four-week period of passive sauna bathing at extreme heat appears to alter the chronology of strength responses. It also seems to induce favorable responses in terms of strength development and body composition. Full article

Background: The multifactorial nature of CrossFit performance remains incompletely understood, particularly regarding sex- and experience-related physiological and biomechanical factors. Methods: Fifteen trained athletes (8 males, 7 females) completed assessments of anthropometry, estimated one-repetition maximums (bench press, back squat, deadlift), squat jump (SJ), maximal oxygen uptake (VO₂max), ventilatory responses ($\dot{\mathrm{V}}$E), and heart rate (HR). Spearman, Pearson, and partial correlations were calculated with Holm and false discovery rate (FDR) corrections. Results: Males displayed greater body mass, lean and muscle mass, maximal strength, and aerobic capacity than females (all Holm-adjusted p < 0.01). Experienced athletes completed Fran faster than beginners despite broadly similar anthropometric and aerobic profiles. In the pooled sample, WOD time showed moderate negative relationships with estimated 1RM back squat (ρ = −0.54), deadlift (ρ = −0.56), and bench press (ρ = −0.65) before correction; none remained significant after Holm/FDR adjustment, and partial correlations controlling for training years were further attenuated. Conclusions: This exploratory study provides preliminary evidence suggesting that maximal strength may contribute to Fran performance, whereas conventional aerobic measures were less influential. However, given the very small sample (n = 15, 8 males and 7 females) and the fact that no relationships remained statistically significant after correction for multiple testing, the results must be regarded as preliminary, hypothesis-generating evidence only, requiring confirmation in larger and adequately powered studies. Full article

Lower limb functional degeneration has become prevalent, notably reducing the core strength that drives motor control. Squats are frequently used in lower limb training, improving overall muscle strength. However, performing continuously with improper techniques can lead to dynamic knee instability. It worsens with little to no motivation to perform these power training motions. Hence, it is crucial to have a gaming-based exercise tracking system to adaptively enhance the user experience without causing injury or falls. In this work, 28 healthy subjects performed exergame-based squat training, and dynamic kinematic features were recorded. The five features acquired from a depth camera-based inertial measurement unit (IMU) (1—Knee shakiness, 2—Knee distance, and 3—Squat depth) and an Anima forceplate sensor (4—Sway velocity and 5—Sway area) were assessed using a Spearman correlation coefficient-based feature selection method. An input vector that defines knee instability is used to train and test the Long Short-Term Memory (LSTM) and Support Vector Machine (SVM) models for binary classification. The results showed that knee instability events can be successfully classified and achieved a high accuracy of 96% in both models with sets 1, 2, 3, 4, and 5 and 1, 2, and 3. The feature selection results indicate that the LSTM network with the proposed combination of input features from multimodal sensors can successfully perform real-time tracking of knee instability. Furthermore, the findings demonstrate that this multimodal approach yields improved classifier performance with enhanced accuracy compared to using features from a single modality during lower limb therapy. Full article

Linear velocity is commonly used to estimate 1-repetition maximum (1RM) from a load–velocity profile (LVP), as well as prescribe training intensity. However, no study has assessed angular velocity, which may be more representative of joint motion. The purpose of this study was to compare the prediction of 1RM from linear velocity (1RM_linear) and angular velocity (1RM_angular) LVPs in men and women. Fourteen recreationally trained college-aged subjects (7 males, 7 females) completed 1RM testing on day 1, then a randomized submaximal (30–90% 1RM) squat protocol on day 2. Linear velocity was measured with a linear position transducer, while angular velocity was recorded using an accelerometer affixed to the thigh. 1RM_angular was not significantly different from actual 1RM (p = 0.951), with a trivial effect size (d = 0.02), and nearly perfect correlation with actual 1RM (r = 0.984). 1RM_linear had a near perfect correlation with actual 1RM (r = 0.991) but was significantly different than actual 1RM (p < 0.001) with a large effect size (d = 1.56). Additionally, 1RM_angular had a significantly (p = 0.020) lower absolute error (6.7 ± 5.3 kg) than 1RM_linear (12.9 ± 8.2 kg). Regardless of prediction method, males (12.9 ± 8.2 kg) had a greater absolute error in 1RM prediction than females (6.7 ± 5.2 kg). During submaximal loads, a significant load × gender interaction was observed for linear velocity (p < 0.001), with men showing faster velocities at 30% (p = 0.009) and 40% (p = 0.044) 1RM, with no significant interaction (p = 0.304) of main effect of gender (p = 0.116). Angular velocity may provide strength and conditioning coaches a more accurate 1RM prediction during submaximal sets of back squat than using linear velocity; however, neither meet all criteria to be considered highly valid. Lastly, the gender differences in linear velocity at submaximal exercises suggest gender-specific considerations in velocity-based training particularly at lighter loads. Full article

Background/Objectives: This study aimed to investigate the anthropometric characteristics, motor performance, and isokinetic strength profiles of elite Portuguese female handball players, as well as to examine the relationships among these variables. Methods: Sixteen national-team female handball players with an average age of 20.25 ± 0.45 years, height of 171.13 ± 8.13 cm and body mass of 72.24 ± 10.96 kg volunteered. Evaluations were conducted in two sessions within one week (24–48 h apart). The first comprised anthropometric and motor performance tests, while the second focused on isokinetic strength assessments of the upper and lower limbs. Pearson correlations assessed variable associations (p < 0.05). Results: Direct correlations were found between height and arm span (r = 0.910) and between internal rotation total work and internal rotation average power (r = 0.960). The 9 m jump throw was associated with the 7 m standing throw (r = 0.670). External rotation peak torque correlated with squat jump performance (r = 0.540) and the 7 m standing throw (r = 0.760) and 9 m jump throw (r = 0.568). Internal rotation peak torque associated with squat jump performance (r = 0.674) and the 7 m standing throw (r = 0.550). Knee extension peak torque correlated with squat jump performance (r = 0.650), while knee extension total work was strongly associated with external rotation total work (r = 0.870). Knee flexion total work was associated with knee flexion peak torque (r = 0.910). Conclusions: The integrated analysis of anthropometric, motor and isokinetic variables revealed distinct strength–performance associations in female handball players, highlighting the role of upper- and lower-limb muscle function in jumping and throwing. Full article

Background/Objectives: Whole-body vibration (WBV) has been widely studied for its effects on neuromuscular activation, circulation, and balance. This study investigates the effect of wearing frequency of vibrating sneakers (18 Hz) on lower limb muscle activation during walking and squatting in middle-aged Koreans (40–60 years old). The objective is to assess whether WBV footwear enhances muscle engagement in both active and sedentary individuals. Methods: A 16-week randomized controlled trial was conducted with 64 participants divided into exercise (walking 30 min, three times a week) and non-exercise groups. Each group was further divided into wearing and non-wearing vibrating sneaker subgroups. Muscle activation of the quadriceps and gastrocnemius was measured using surface electromyography before and after the intervention. Results: Participants wearing vibrating sneakers showed significantly increased quadriceps and gastrocnemius activation during squatting and walking compared to non-wearers (p < 0.05). The exercise group wearing WBV sneakers exhibited greater improvements in muscle activation than the non-exercise group, indicating that WBV enhances the benefits of regular walking. However, no significant differences were observed in some lower leg muscles, suggesting that WBV effects may vary based on movement type and muscle group. Conclusions: Findings suggest that WBV sneakers (18 Hz) can enhance muscle activation during dynamic movements, potentially offering a low-impact training alternative for improving lower limb strength. These results provide valuable insights for exercise professionals, rehabilitation specialists, and wearable sensor developers, highlighting the potential of WBV footwear in neuromuscular conditioning and injury prevention. Full article

This study examined the physiological and performance adaptations of association football (soccer) players during a six-week transitional (off-season) period following the competitive season through a remotely supervised, periodized training program. Fifteen male players (19.57 ± 1.14 years; training experience: 13.60 ± 1.81 years) from the Greek Super League 2 completed pre- and post-intervention laboratory assessments, including anthropometry, cardiopulmonary function, isokinetic strength, and jump performance. The program integrated high-intensity interval training, aerobic conditioning, and individualized resistance training, adjusted according to test results. Anthropometric parameters remained stable. Maximal oxygen uptake (VO₂max) increased significantly by 2.8% (56.31 ± 3.87 vs. 57.91 ± 3.02 mL/kg/min), while anaerobic threshold time and velocity declined by 6.2% (472.87 ± 35.06 vs. 443.33 ± 24.69 sec) and anaerobic threshold velocity fell by 6.1% (15.97 ± 1.17 vs. 15.00 ± 0.91 km/h), indicating a partial preservation of aerobic capacity but reductions in submaximal endurance. Isokinetic strength of the quadriceps and hamstrings was maintained across angular velocities, but squat jump height decreased significantly by 4.3% (p = 0.033), suggesting a loss of concentric-only explosive power despite stable countermovement jump performance. These findings indicate that targeted off-season training can maintain overall physical readiness, body composition, and VO₂max, but may require additional endurance and concentric power elements to preserve all performance qualities essential for the competitive season. Overall, the program effectively preserved most performance variables with only minor decrements, representing a favorable outcome for the off-season; however, if greater asymmetries, deficits, or other training targets are identified, more specific adjustments to training intensities, such as the inclusion of additional endurance and concentric-only power elements, may be required to achieve significant improvements. Full article

Background: Childhood overweight and obesity are increasing public health concerns globally, with a high prevalence in Chile, particularly in rural areas. Excess weight may impair physical fitness, affecting children’s overall health and development. Objectives: This study aimed to compare the physical fitness of schoolchildren with normal weight (NW) and overweight/obesity (OW/OB) from a rural school in Maule, Chile. Methods: A total of 87 students (boys and girls, aged 9–14 years) were evaluated and classified into NW and OW/OB groups based on their body mass index. Physical fitness was assessed using the 6 min walk test (6MWT) for cardiovascular endurance, handgrip strength (HGS) and squat jump (SJ) for muscular strength, 20 m sprint for speed, and 4 × 10 m shuttle run for agility. Results: Significant differences were found between groups in most physical fitness components. The NW group covered 11.13% more distance in the 6MWT than the OW/OB group (p < 0.001; d = 1.28). NW children also performed better in the 20 m sprint (p = 0.023; d = 1.02) and the 4 × 10 m shuttle run (p < 0.001; d = 0.72). SJ was higher in the NW group (p = 0.004; d = 0.45). No significant differences were found in HGS (p = 0.893; d = 0.01). Conclusions: Children with normal weight demonstrated better physical fitness compared to their overweight or obese peers. These findings support the need for targeted strategies to prevent overweight and obesity in rural schoolchildren to improve physical health and functional capacities. Full article

Background: Age-related declines in skeletal muscle quality and quantity contribute to frailty and sarcopenia, leading to physical dysfunction in older adults. In particular, the selective atrophy of fast-twitch fibers is closely linked to reduced lower limb strength and increased fall risk. This study aimed to evaluate the effects of habitual body weight resistance training on muscle fiber recruitment patterns during maximal voluntary contraction (MVC) and squatting movements using spectral characteristics of surface electromyography (EMG). Methods: Fifty healthy community-dwelling older adults (28 males, 22 females; aged 64–84 years) were categorized into exercise and non-exercise groups based on training habits. Surface EMG signals were recorded from the rectus femoris muscle during MVC, normal squat, half-squat, and squat movements. Power spectral density (PSD) was analyzed using Welch’s method and divided into frequency bands: type I (20–60 Hz), type IIa(1) (60–115 Hz), type IIa(2) (115–170 Hz), and type IIx (170–350 Hz). Results: While statistical significance was limited, the exercise group tended to show higher ratio PSDs in type IIa and IIx bands, and lower PSDs in the type I band during MVC. During half-squats, the non-exercise group exhibited higher contributions above 60 Hz, suggesting inefficient fast-twitch fiber recruitment. Conclusions: Habitual body weight resistance training may influence muscle fiber recruitment patterns in older adults. EMG spectral analysis offers a non-invasive means to detect age- and training-related neuromuscular adaptations. Full article

Objective: This study aimed to evaluate the effects of Cistanche deserticola Y.C. Ma (CD) supplementation on muscle strength and recovery in individuals with and without resistance training experience. Methods: A randomized, double-blind, placebo-controlled trial was conducted with 48 male participants, including 24 resistance-trained and 24 untrained individuals. Participants were stratified by training status and randomly assigned to either the CD or placebo (PLAC) group. All subjects completed a standardized resistance training program three times per week for eight weeks. The CD group received 5 g of CD extract twice daily, while the PLAC group consumed a matched placebo. Assessments included one-repetition maximum (1RM) for bench press and squat, maximal voluntary isometric contraction (MVIC), and repetitions to failure (RTF). Blood biomarkers including serum testosterone, cortisol, C-reactive protein (CRP), and creatine kinase (CK) were also measured. Results: No significant differences in dietary energy intake or macro-nutrient composition were observed based on two 5-day dietary records collected before baseline testing and at the end of the intervention. Among untrained individuals, the CD group showed significantly greater improvements in 1RM bench press and squat compared with the PLAC group (p < 0.05), with MVIC and RTF also significantly increased (p < 0.01). Serum cortisol levels were reduced (p < 0.05), and significant improvements were observed in testosterone, CRP, and CK (p < 0.01). In trained individuals, CD supplementation led to significant increases in 1RM squat and MVIC (p < 0.05), along with improvements in testosterone and cortisol levels (p < 0.05) and marked reductions in CRP and CK (p < 0.01). Conclusions: Daily supplementation with 5 g of CD extract for eight consecutive weeks significantly enhanced muscle strength and endurance in males with different training backgrounds and facilitated post-exercise recovery by modulating hormonal responses and reducing stress levels and inflammation. These findings provide experimental evidence supporting the application of CD in sports nutrition. Full article

Objective: This study aimed to determine the acute effects of specific exercises, commonly used in resistance training programs, performed at two intensities (low and high) with equal volume, on blood pressure in individuals with pharmacologically controlled hypertension. Methods: A crossover clinical trial was conducted with 26 participants with hypertension, each completing two resistance training sessions, one low-intensity and one high-intensity, including squats, rows, deadlifts, and bench presses. The exercise intensity for the first session was randomly assigned, and blood pressure was measured using an automated device before and immediately after each exercise. Comparisons between baseline and post-exercise values were analyzed, with a significance level set at 5%. Results: The results showed that systolic blood pressure (SBP) increased during squats, rows, and deadlifts compared to baseline, with the deadlift producing the highest values. For diastolic blood pressure (DBP), no significant differences were observed from baseline, but the squat and deadlift elicited higher values than the rows and bench press. Additionally, high-intensity training resulted in lower DBP values compared to the low-intensity protocol. Conclusion: Resistance exercise increases SBP regardless of intensity, with the squat and deadlift producing the most significant changes, while high-intensity training leads to lower DBP values than low-intensity protocols in the studied participants. Full article

Background: This study compared the acute effect of performing quarter (QS) and parallel (PS) squat with variable resistance (VR) on countermovement jump (CMJ) performance. Methods: Fifteen resistance trained athletes (age: 27.0 ± 3.7 years, bodyweight: 68.4 ± 7.7 kg, height: 169.7 ± 6.9 cm) performed either the QS or PS to induce post-activation performance enhancement on two separate occasions. During each session, participants performed three repetitions of baseline CMJ prior to performing three repetitions of either QS or PS at their three-repetition maximum load. Participants then performed the post-test CMJ after a five-minute recovery period. Results: Both conditions resulted in increased jump height (QS: p < 0.001, g = 0.19, PS: p < 0.001, g = 0.35). Countermovement depth and time to take-off were significantly decreased in QS (p < 0.001, g = 0.63 and p = 0.005, g = 0.30, respectively) but significantly increased in PS (p = 0.027, g = 0.39 and p < 0.001, g = 0.36, respectively). Mean propulsion force was significantly increased in QS (p < 0.001, g = 0.23) but significantly decreased in PS (p = 0.083, g = 0.13). PS resulted in greater change in jump height (p < 0.001, g = 1.34) and time to take-off (p = 0.005, g = 1.25), while QS resulted in greater change in countermovement depth (p < 0.001, g = 2.33) and mean propulsion force (p < 0.001, g = 1.67). Conclusions: The results showed that performing PS and QS with VR was effective in enhancing CMJ height. However, the two conditions resulted in participants adopting different jump strategies when performing the post-test CMJ. Full article

Optokinetic motion capture (OMC) is the gold standard for measuring the kinematics associated with lifting posture. Unfortunately, limitations exist, including cost, portability, and marker occlusion. The purpose of this study is to evaluate the agreement between OMC and inertial measurement units (IMUs) for quantifying joint kinematics during squat–pivot and stoop–twist lifting tasks. Ten unimpaired adults wearing both IMUs and OMC markers performed 24 lifting trials. Correlation coefficients and Root Mean Square Error (RMSE) between IMU and OMC time-series signals were computed for trunk and lower-extremity joints. Peak values obtained from each system during each trial were analyzed via Bland–Altman plots. Results show high correlations for trunk, knee, and ankle flexion angles (>0.9) and ankle rotation angles (>0.7). Moderate correlation was found for trunk axial rotation and lateral flexion angles (0.5–0.7). RMSE was under 9° for each angle. Biases between systems ranged from 0.3° to 16°. Both systems were able to detect statistically significant differences in peak angles between the two postures (p < 0.05). IMUs show promise for recording field data on complex lifting tasks. Full article