Search Results (72)

Background: The study aimed to examine recovery time between sets (30 s vs. 2 min) during elastic band training for jumping, sprinting, COD, and repeated high-intensity efforts in young padel players. Methods: Twelve highly trained male padel players were allocated to one of the two groups randomly (short recovery [SRG] or long recovery [LRG]) and evaluated the triple hop test (3HJ), linear (10 m) and multidirectional (5 + 5 m sprint with a direction change of 45°) tests, and the repeated sprint ability (RSA) test after 3 weeks of training intervention. After 3 weeks, there was a 3-week washout period to cross both groups, and the participants then performed the opposite training program. Both groups performed two sets of four exercises, each with six repetitions, with an elastic band, recovering 30 s (SRG) or 2 min between exercises (LRG). Results: No between-training-program differences were established (p < 0.05). SRG showed a better trend in the 3HJ with the right (effect size (ES) = 0.85), while LRG showed small advantages in the 5 m and 10 m sprints (ES = 0.33 to 0.36). SRG also showed small to moderate improvements in COD on both sides (ES = 0.46 to 0.49), although period effects (p < 0.05) indicated the influence of familiarization. In RSA, LRG showed a slight tendency to improve the mean and the best time (ES = 0.24 to 0.41), while SRG showed an advantage in the percentage of decrement (ES = 0.54). Conclusions: SRG appeared more effective in horizontal jumping, COD, and fatigue resistance during the RSA test, whereas LRG may show small advantages in acceleration and RSA performance. Although the effects were mostly small and not statistically significant, the observed trends could have practical relevance for planning specific training programs focused on power, speed, and fatigue resistance in padel players. Full article

The present article relates to the description of phenomenological relations of amorphous material behavior within the framework of viscoelasticity and elastic-viscoplasticity theory, as well as to the creation of its digital analog. Ultra-high-molecular-weight polyethylene (UHMWPE) is considered in the study. The model is based on the results of a series of experimental studies. Free compression of cylindrical specimens in a wide range of temperatures [−40; +80] °C and strain rates [0.1; 4] mm/min was performed. Cylindrical specimens were also used to determine the thermal expansion coefficient of the material. Dynamic mechanical analysis (DMA) was performed on rectangular specimens using a three-point bending configuration. Maxwell and Anand models were used to describe the material behavior. In the framework of the study, the temperature dependence of a number of parameters was established. This influenced the mathematical formulation of the Anand model, which was adapted by introducing the temperature dependence of the activation energy, the initial deformation resistance, and the strain rate sensitivity coefficient. Testing of the material models was carried out in the process of analyzing the deformation of a spherical bridge bearing with a multi-cycle periodic load. The load corresponded to the movement of a train on a bridge structure, without taking into account vibrations. It is shown that the viscoelastic model does not describe the behavior of the material accurately enough for a quantitative analysis of the stress–strain state of the structure. It is necessary to move on to more complex models of material behavior to minimize the discrepancy between the digital analog and the real structure; it has been established that taking into account plastic deformation while describing UHMWPE would allow this to be performed. Full article

Background: Shoulder exercises using elastic resistance integrated within the kinetic chain appear to modify scapular control strategies; however, a deeper understanding of these mechanisms is still needed. Objectives: We aim to compare three-dimensional scapular kinematics during two exercises performed on different bases of support, under both non-resisted and resisted conditions in asymptomatic adults. Methods: This cross-sectional study analyzed three-dimensional shoulder kinematics in 36 healthy adult male participants during the overhead squat and kneeling position exercises. Movement patterns were evaluated by phase using statistical parametric mapping. Results: Scapular internal/external rotation demonstrated a main effect for exercise type (p = 0.04), a main effect for resistance conditions (p < 0.00), and a significant exercise–resistance interaction (p = 0.04) during arm elevation. During the lowering phase, a main effect was observed for exercise types (p = 0.04) and exercise conditions (p < 0.00). Scapular upward rotation showed a main effect for exercise type (p = 0.02) and resistance conditions (p = 0.04) during arm elevation. During the lowering phase, a significant main effect was observed for exercise type (p = 0.01) and exercise conditions (p < 0.00). Scapular posterior tilt presented a main effect for exercise type (p < 0.00), a main effect for exercise condition (p = 0.01), and an exercise–resistance interaction (p = 0.04) during arm elevation. During the lowering phase, a main effect for exercise type (p < 0.00), a main effect for exercise condition (p = 0.02), and an exercise–resistance interaction (p = 0.00). Conclusions: The resistance and exercises demonstrated different kinematic strategies that helped maintain scapular stability during movement. Full article

Objectives: To examine three elastic band resistance training (EB-RT) modalities—high-velocity (HVRT), accentuated eccentric (Aecc), and maximal strength (Max)—on bone health, strength, redox-inflammatory profile, and neuroplasticity in sedentary older adults. Methods: Sixty-one participants (69.41 ± 4.61 years) were randomly assigned to HVRT (n = 21), Aecc (n = 13), Max (n = 10), or passive controls (n = 17). Training was conducted three times a week for 16 weeks. Sessions included four sets of alternating upper- and lower-limb EB exercises, with intensity guided by the OMNI–RES EB scale. HVRT emphasized explosive concentric actions [~70% one-repetition maximum (1RM); 3–4 rating of perceived exertion in the first repetition (RPE-1)]. Aecc performed 5 s eccentric overload [>100% 1RM; 7–8 RPE-1]. Max employed controlled 2 s concentric/eccentric actions [~80–85% 1RM; 7–8 RPE-1]. Results: All training groups improved isokinetic strength (p < 0.01, g = 0.91–2.40). HVRT increased brain-derived neurotrophic factor (BDNF) (p = 0.019, g = 0.42) and glutathione peroxidase (GPx) (p < 0.001, g = 0.31). Aecc elicited the strongest osteoanabolic and antioxidant effects (P1NP, p = 0.001, g = 1.21; β-CTX, p < 0.001, g = 1.82; F2-isoprostanes, p = 0.007, g = 0.94). Max induced moderate bone turnover benefits (P1NP, p = 0.005, g = 1.08; β-CTX, p < 0.001, g = 1.12), but no GPx or BDNF gains. Controls maintained or declined all variables. Conclusions: EB-RT over 16 weeks improved most outcomes overall, showing modality-specific trends: HVRT favored neuroplasticity, Aecc enhanced redox-inflammatory and bone remodeling responses, and Max improved strength and bone health. These findings support elastic band resistance training as a safe and individualized strategy for healthy aging. Full article

This study investigated the effects of lightweight wearable resistance on the kinetics and kinematics of squat jumps (SJ) and countermovement jumps (CMJ) with 2%, 4%, and 6% body mass (BM). Twenty male athletes (age: 18.05 ± 0.6 years; weight: 76.4 ± 7.6 kg; height: 182.4 ± 5 cm) were assessed on a force plate. Key variables included jump height (JH), concentric (ConT) and eccentric (EccT) phase durations, concentric impulse (CI), mean force (CMF), mean velocity (CMV), mean power (CMP), and relative metrics. Elastic utilization ratios (EUR) were calculated to quantify stretch-shortening cycle enhancement. Load led to decrements in both jumps but with varying sensitivity. With 2% BM the CMJ significantly reduced JH (−8.6%), EccT (−7%), CMV (−4.1%), rCI (−4.1%), rPP (−4.4%), and velocity at PP (−4.8%), whereas variables in the SJ were non-significant until 4–6% BM. EURs observed the greatest differences with 2% BM with JH, CMV, rCMP, and VPP all significantly decreasing (p < 0.05). The varying sensitivity to load across variables observed in the two jumps supports the hypothesis that SJ and CMJ offer distinct diagnostic insights due to varying MTU contraction dynamics and neural factors. This has implications for WR use in training. Further, absolute metrics showed limited load sensitivity. However, when accounting for body mass, relative metrics revealed substantial declines. This indicates absolute values can misrepresent the effects of WR loading. Full article

This study introduces MIRANDA, a computer vision system, and RELAPP, a complementary force measurement system, developed for characterizing viscoelastic materials. Our aim was to evaluate their combined ability to predict key rheological parameters and demonstrate their utility in material analysis, offering an alternative to traditional methods. We analyzed five distinct flour dough samples, correlating MIRANDA and RELAPP variables with established rheological reference values. Support Vector Machine (SVM) regression models were trained using MIRANDA’s stable TR and elasticity data to predict industrially relevant parameters: baking strength (W), tenacity (P), extensibility (L), and final viscosity (RVU) from Chopin alveograph and viscosimeter. The predictive models showed promising results, with R² values of 0.594 (p = 0) for W, 0.575 (p = 0) for P, and 0.612 (p = 0.03763) for viscosity, all statistically significant. While these findings are promising, it is important to note that the small sample size may limit the generalizability of these models. The synergy between the systems was evident, exemplified by strong positive correlations, such as between MIRANDA’s Elasticity and RELAPP’s c_exp (parameter ‘c’ of its mathematical model m1, r = 0.858) and final resistive force (r = 0.839). Despite the limited sample size, these findings highlight MIRANDA’s versatility and speed for efficient material characterization. MIRANDA and RELAPP offer significant industrial implications for viscoelastic materials, including accelerating development cycles and enhancing continuous quality control. This approach has strong potential to reduce reliance on slower, traditional methods, warranting further validation with larger datasets. Full article

Objectives: Elastic band training is a popular alternative to traditional resistance methods, but its effects on sport-specific performance in team athletes remain inconsistent. This systematic review and meta-analysis aim to evaluate the efficacy of elastic band training on muscular strength, linear sprint, change of direction (COD), and jump height in team sport athletes. Methods: Following PRISMA guidelines, a comprehensive search was conducted in PubMed, Web of Science, and Scopus for randomized controlled trials and quasi-experimental studies. The quantitative synthesis included studies comparing elastic band training interventions with control groups receiving routine training, habitual physical activity, or no additional resistance training intervention. Data were extracted using a standardized form, and a meta-analysis was performed using a random-effects model. Standardized mean differences (SMDs) and 95% confidence intervals (CIs) were calculated to determine the pooled effect of the intervention on key performance indicators. A total of 729 athletes were included. Results: The meta-analysis showed a statistically significant positive effect of elastic band training on lower limb explosive power (SMD = 1.43, p = 0.01), change of direction performance (SMD = −2.54, p = 0.01), and sprint performance (SMD = −1.64, p = 0.01). Conclusions: Elastic band training is a highly effective and practical method for significantly improving key physical performance indicators, including explosive power, COD, and sprint ability, in team sport athletes. Its portability and adaptability make it a valuable alternative or complement to conventional resistance training. Full article

Objective: this systematic review with a meta-analysis aimed to evaluate the available body of published peer-reviewed randomized controlled trial (RCT) studies on the effects of different doses and types of strength training (ST) on body composition, physical performance, and protein or calcium intake in older people with osteosarcopenia. Method: a systematic literature search was conducted between July 2024 and August 2025 using five databases: PubMed, Medline, CINAHL Complete, Scopus, and Web of Science. PRISMA, TESTEX, RoB 2, and GRADE tools assessed methodological quality and certainty of evidence. Hedge’s g effect sizes were calculated for the abovementioned variables for the meta-analysis. Results: the protocol was registered in PROSPERO (code: CRD42025643858). Of 141 registers, seven RCTs with 349 participants were included. Seven overall and two subgroup meta-analyses showed significant increases in skeletal muscle mass index (SMMI; p < 0.01), maximal isometric handgrip strength (MIHS; p = 0.03), and protein intake (p = 0.03). There were no significant differences in bone mineral density (BMD), body fat percentage (BFP), gait speed, and calcium intake. However, meta-analysis by subgroups showed significant decreases in BFP (p = 0.01) in favor of elastic band training versus resistance training, with no significant differences in BMD. Conclusions: ST in older people with osteosarcopenia conditions increases SMMI, MIHS, and protein intake. Full article

Background: Aging is associated with reduced joint flexibility and balance, which increases the risk of falls, especially during stair descent where motor control is critical. Stretching has been shown to improve ankle range of motion and gait speed. This study investigated the effects of a 4-week training program combining stretching plus resistance training (RT) with elastic bands on functional capacity and ankle stability during stair descent in older women. Methods: Twenty-four active older women (mean age: 73.1 ± 0.97 years) were randomly assigned to static stretching (SS), dynamic stretching (DS) and control (CG) groups. All participants completed two weekly 60 min sessions consisting of progressive RT preceded by three different warm-ups. The SS and DS groups completed static or dynamic stretching, while the CG walked. Assessments included 30s-Chair Stand (30s-CS), Handgrip Strength (HGS), Time Up and Go (TUG), Chair Sit and Reach (CSR), Rating of Perceived Exertion (RPE), and ankle kinematics during stair descent. Results: All groups improved 30s-CS and TUG (p < 0.05). Only the SS group improved CSR in both legs and the ankle dorsiflexion angle during stair descent at final foot contact (p = 0.002). RPE increased over time across all groups (p < 0.0001); however, the SS and DS groups reported lower exertion than the CG group in first–second weeks (p = 0.0001–0.003). Conclusions: SS prior to progressive RT improved flexibility and ankle kinematics during stair descent, thus reducing the perception of effort particularly during the initial training phase. These findings indicate the effectiveness of SS as a warm-up strategy for increasing ROM and potentially reducing the risk of falls in this population. Full article

The superiority of Variable Resistance Training (VRT) over traditional Constant Resistance Training (CRT) for enhancing lower-limb performance is debated, with previous meta-analyses limited by aggregating disparate exercises. This systematic review and meta-analysis, the first to focus exclusively on the squat, compared the acute and long-term effects of VRT versus CRT on maximal strength and explosive power. Following PRISMA guidelines, 20 studies were analyzed (literature search up to 15 June 2025), with Hedges’ g used for effect size (ES) calculation. Results demonstrated VRT’s superiority for both acute (ES = 0.34) and long-term adaptations. Acutely, effects peaked with an 8–12 min recovery (ES = 0.43). Long-term, VRT produced greater gains in maximal strength (ES = 0.31) and explosive power (ES = 0.17). Subgroup analyses on maximal strength revealed that elastic bands were highly effective (ES = 0.67), particularly in trained individuals (ES = 0.35), males (ES = 0.41), within cycles < 8 weeks (ES = 0.44), and at frequencies of ≤2 sessions/week (ES = 0.45). For explosive power, chains were most effective (ES = 0.37), significantly improving jumping performance but not sprinting. In conclusion, VRT is a more effective modality for squat training; optimal programs should utilize elastic bands for strength and chains for power, with strength-focused blocks being short-term (<8 weeks) and lower-frequency (≤2 sessions/week) for trained individuals. Full article

Background: This study aimed to investigate how barbell type (elastic vs. inelastic) and lifting speed affect postural stability and lower limb muscle activation during the single-leg deadlift (SLDL), a common unilateral exercise in rehabilitation and performance training. Methods: Twenty-seven healthy adults performed SLDLs using both elastic and inelastic barbells under three lifting speeds (normal, fast, and power). Center of pressure (COP) displacement in the anterior–posterior (AP) and medial–lateral (ML) directions and electromyographic (EMG) activity of eight lower limb muscles were measured. Results: COP displacement was significantly lower when using elastic barbells (AP: F = 6.509, p = 0.017, η² = 0.200, ω² = 0.164; ML: F = 9.996, p = 0.004, η² = 0.278, ω² = 0.243). EMG activation was significantly higher for the gluteus medius, biceps femoris, semitendinosus, and gastrocnemius (all p < 0.01), especially under power conditions. Significant interactions between barbell type and speed were found for the gluteus medius (F = 13.737, p < 0.001, η² = 0.346, ω² = 0.176), semitendinosus (F = 6.757, p = 0.002, η² = 0.206, ω² = 0.080), and tibialis anterior (F = 3.617, p = 0.034, η² = 0.122, ω² = 0.029). Conclusions: The findings suggest that elastic barbells improve postural control and enhance neuromuscular activation during the SLDL, particularly at higher speeds. These results support the integration of elastic resistance in dynamic balance and injury prevention programs. Full article

Concrete in cold areas is often subjected to a freeze–thaw cycle period, and a harsh environment will seriously damage the structure of concrete and shorten its life. The frost resistance of concrete is primarily evaluated by relative dynamic elastic modulus and mass loss rate. To predict the frost resistance of concrete more accurately, based on the four ensemble learning models of random forest (RF), adaptive boosting (AdaBoost), categorical boosting (CatBoost), and extreme gradient boosting (XGBoost), this paper optimises the ensemble learning models by using a dynamic multi-stage optimisation algorithm (DMSOA). These models are trained using 7090 datasets, which use nine features as input variables; relative dynamic elastic modulus (RDEM) and mass loss rate (MLR) as prediction indices; and six indices of the coefficient of determination (R²), mean square error (MSE), root mean square error (RMSE), mean absolute error (MAE), correlation coefficient (CC), and standard deviation ratio (SDR) are selected to evaluate the models. The results show that the DMSOA-CatBoost model exhibits the best prediction performance. The R² of RDEM and MLR are 0.864 and 0.885, respectively, which are 6.40% and 11.15% higher than those of the original CatBoost model. Moreover, the model performs better in error control, with significantly lower MSE, RMSE, and MAE and stronger generalization ability. Additionally, compared with the two mainstream optimisation algorithms (SCA and AOA), DMSOA-CatBoost also has obvious advantages in prediction accuracy and stability. Related work in this paper has a certain significance for improving the durability and quality of concrete, which is conducive to predicting the performance of concrete in cold conditions faster and more accurately to optimise the concrete mix ratio whilst saving on engineering cost. Full article

Limited data exist on the underlying physiological phenomena of aerobic training; the impulse oscillometry method, allowing the assessment of small airways and lung periphery in addition to standard lung function testing, might be a useful addition to rehabilitation programs. Background/Objectives: This study aimed to determine the immediate effect of a structured low-intensity aerobic training program on small airway function in healthy volunteers to explore potential implications for long-term COPD care. Methods: Thirty-six healthy volunteers were recruited between May 2024 and January 2025; each participant underwent a lung function testing session, followed by low/moderate-intensity aerobic exercise, and, after 15 min, by a second impulse oscillometry assessment. Results: There was a statistically significant reduction in airway resistance following the physical exertion for the whole group (mean difference 0.03 kPa/L/s, 95%CI 0–0.6 kPa/L/s); significantly lower values were recorded for the reactance component X5 (0.02 kPa/L/s, 95%CI 0–0.4 kPa/L/s) for the normal weight subgoup (n = 24). These results, corroborated with literature data, suggest optimization of the distribution of the airflow and possibly alteration of the elastic properties of the thoracic structures following even low-intensity effort. Conclusions: Low-intensity upper body strength and aerobic training seem to have an immediate respiratory beneficial effect on healthy volunteers manifested as a reduction in airway resistance. The underlying mechanism might be related to improved contractility of respiratory muscles, but changes in lung parenchyma elasticity may also be involved, possibly reflecting modifications of ventilation heterogeneity. Impulse oscillometry may be superior to spirometry in monitoring the effects of aerobic training, considering the additional data it provides, and could be used to optimize and personalize rehabilitation protocols. Full article

(1) Background: Limited research has examined elastic resistance preconditioning effects on post-activation performance enhancement (PAPE) using the rate of perceived exertion (RPE) as an intensity indicator. This pilot study aimed to evaluate the application of RPE to the elastic resistance push-press (ERPP) exercise performed at maximum velocity for its effects on PAPE. (2) Methods: Twenty-four trained, healthy young adults participated in this study and performed both a conventional warm-up and a warm-up combined with six repetitions of an elastic resistance push-press (ERPP) at 85% 1RM/RPE of the first repetition (RPE-1) of 6 out of 10. The pre-post variables assessed were push-ups, a countermovement jump (CMJ), and 10 and 20 m sprints. A repeated-measures ANOVA was conducted. Additionally, between-subject variability was adjusted for individual performance. (3) Results: In the push-up, a significant improvement (p ≤ 0.05) of 20.41% in mean propulsive velocity was observed among the less strong participants. A medium effect size improvement (d = 0.47; p = 0.13) was observed in CMJ performance (7.93%) among the less strong participants. Significant improvements were noted in sprint performance over 10 m (8.07%) and 20 m (6.23%) in the ERPP group compared with the standard warm-up, particularly in the less strong participants. The stronger participants exhibited no significant changes in either variable. (4) Conclusions: We concluded that ERPP effectively induced PAPE in the less strong participants. Additionally, RPE-1 is proposed as a tool to monitor intensity in elastic band resistance to induce PAPE. Full article

Background and Objectives: Individuals with chronic obstructive pulmonary disease (COPD) often exhibit some degree of intolerance to physical exercise and several limitations in daily activities. Therefore, the objective of this study was to conduct a scoping review on the characteristics—frequency, intensity, time, and type (FITT)—and the effects of exercise programs on quality of life and functional capacity in individuals with COPD. Materials and Methods: The present review included 21 studies that were scoping-reviewed to describe their main findings and training characteristics. Results: The participants across studies ranged in age from ~39 to 76 years with mild to very severe COPD stages. The results showed that, among all studies, eleven used cardiorespiratory training (e.g., walking or cycling), five used strength training (e.g., exercises with elastic bands or traditional resistance training), and five implemented combined training (i.e., cardiorespiratory and strength exercises). Conclusions: Overall, all training protocols improved aerobic capacity (cardiorespiratory training), strength (resistance training), and both capacities together (combined training). In conclusion, this review provided complementary insights to existing exercise prescription guidelines, particularly concerning cardiorespiratory, strength, and combined training in individuals with COPD. However, the methodologies of the training protocols varied widely, and detailed descriptions of FITT components were often incomplete or lacking clarity, especially regarding the specific exercises used. Future research should include more comprehensive spirometry variables such as forced expiratory volume 1 or forced vital capacity, as these are critical for determining COPD stages. Thus, there is a clear need for more high-quality research with robust methodological design in the context of exercise interventions for individuals with COPD. Full article