Search Results (143)

This study investigated the effects of a single-night sleep extension protocol on physical performance and cognitive function in physically active university students across different times of day. Using a within-subjects, counterbalanced crossover design, 24 physically active university students (17 males, 7 females; age: 22.7 ± 1.6 years) completed performance assessments under normal-sleep and sleep-extension conditions. Participants’ sleep was monitored via wrist actigraphy, and a comprehensive assessment battery comprising vertical jumps, Y-Balance tests, medicine-ball throws, 5 m shuttle-run tests, reaction-time tests, and digit-cancellation tests was administered at baseline (8 PM), morning (8 AM), and afternoon (4 PM). Sleep extension increased total sleep time by approximately 55 min (531.3 ± 56.8 min vs. 476.5 ± 64.2 min; p < 0.001, d = 0.91). Significant improvements were observed in 5 m shuttle-run performance at 8 AM (best distance: 102.8 ± 11.9 m vs. 93.3 ± 8.5 m, p < 0.001, d = 0.93; fatigue index: 13.1 ± 8.3% vs. 21.2 ± 9.5%, p < 0.001, d = 0.90), squat-jump heights (28.2 ± 8.0 cm vs. 26.3 ± 7.2 cm, p = 0.005, d = 0.25), simple reaction time (252.8 ± 55.3 ms vs. 296.4 ± 75.2 ms, p < 0.001, d = 0.66), and digit-cancellation performance (67.6 ± 12.6 vs. 63.0 ± 10.0 targets, p = 0.006, d = 0.40). Sleep extension significantly enhances both physical and cognitive performance in physically active individuals, with effects more pronounced during morning hours, partially attenuating typical circadian performance decline and establishing sleep extension as an effective, non-pharmacological strategy for optimizing performance capabilities. Full article

Background: This study aimed to compare the immediate effects of small-sided games (SSGs) and running-based high-intensity interval training (HIITrb) on serum brain-derived neurotrophic factor (BDNF) levels, cognitive performance, and enjoyment in young, male soccer players. Methods: Twenty-four soccer players [age: 19.2 ± 0.8 years] completed one session each of four-a-side SSG or HIITrb in a randomized, counterbalanced, and crossover design, with a one-week washout period. Blood samples and Trail Making Tests (TMTs) A and B were measured before and after exercise. Heart rate (HR) was monitored throughout the games, and ratings of perceived exertion (RPE) and enjoyment were collected at the end of the measurements. Results: The results show no significant effects of time (p > 0.775), group (p > 0.276) or time × group interaction (p > 0.199) on BDNF levels. For TMT-A, the time effect (p = 0.866) and group effect (p = 0.057) were not significant; however, the time × group interaction was significant (p < 0.019), indicating a superior performance in the SSG compared to HIITrb. In the TMT-B, significant effects were observed for both time (p < 0.001) and group (p < 0.001), while the time × group interaction effect was not statistically significant (p > 0.061). Furthermore, enjoyment levels did not differ significantly between conditions (p = 0.976). Conclusions: These findings suggest that four-a-side SSG may enhance processing speed compared to HIITrb without changes in serum BDNF levels. Coaches may consider using 4v4 SSG formats in early training sessions or warm-ups to stimulate processing speed and mental readiness in young soccer players. Full article

Background/Objectives: Power indices may provide valuable information for performance and injury prevention in soccer players, so increasing the knowledge about them seems essential. Therefore, this study aimed to establish limb-specific normative values for flywheel-derived power indices in professional soccer players, while accounting for limb performance or ability, to explore the relationships between power indices across variables and to compare the power outcomes related to these indices between injured and non-injured players within four months post-assessment. Methods: Twenty-two male professional soccer players (age: 26.6 ± 4.6 years; competitive level: Belgian second division) were recruited from a single elite-tier club to participate in this cross-sectional diagnostic study. Participants underwent a standardized assessment protocol, executed in a rotational inertial device, comprising six unilateral exercises focused on the lower limbs: hip-dominant quadriceps (Qhip), knee-dominant quadriceps (Qknee), hip-dominant hamstrings (Hhip), knee-dominant hamstrings (Hknee), adductor (Add), and abductor (Abd). The testing session incorporated a randomized, counterbalanced design, with each exercise comprising two sets of eight maximal concentric–eccentric repetitions per limb. Leg dominance was operationally defined as the self-reported preferred limb for ball-striking tasks. Power indices were calculated from these exercises. Results: No significant differences in flywheel-derived power indices were found between limbs or between injured and non-injured players. However, significant correlations between indices were found in all power variables, with the Qhip:Qknee and Hhip:Hknee concentric ratios emerging as the most clinically actionable biomarkers for rapid screening. Conclusions: These results suggest the necessity of including more variables for injury prediction. Moreover, power indices could be considered based on the classification of limbs as “strong” or “weak”. Full article

Obesity is associated with reduced cardiorespiratory fitness and altered metabolic responses. However, the acute effects of forward and backward locomotion training in individuals with a body mass index (BMI) ≥ 30 remain underexplored. This study investigated this population’s cardiorespiratory, metabolic–perceptual, and muscle electromyography (EMG) responses to forward and backward locomotion at different speeds. Twenty-eight male participants were divided into four seven-member groups, following a randomized crossover design with a Latin Square-like counterbalancing approach. Participants completed four 10 min walking conditions (3 km/h forward, 3 km/h backward, 4 km/h forward, and 4 km/h backward) on separate days, with cardiorespiratory parameters (e.g., VO₂, VCO₂, and heart rate), metabolic responses (e.g., lactate and energy expenditure), and lower-limb muscle EMG activity measured. Statistical analysis using two-way repeated measures (MANOVA) revealed significant direction effects (p < 0.05) on VO₂, VCO₂, heart rate, energy expenditure, Borg RPE, final lactate, and the EMG activity of quadriceps, hamstrings, and tibialis anterior, but not on pre-lactate or soleus activity (p > 0.05). These findings provide valuable insights for optimizing exercise programs in obese individuals, supporting tailored movement strategies to enhance physiological outcomes. Full article

Objectives: Transcranial alternating current stimulation (tACS) can enhance primary motor cortex (M1) excitability and improve motor skill when delivered unilaterally to the dominant hemisphere. However, the impact of tACS on contralateral M1 excitability both during and after application has not been studied. The purpose of this study was to examine the effects of tACS delivered to the dominant left M1 on the excitability of the unstimulated contralateral non-dominant right M1. Methods: This study implemented a double-blind, randomized, SHAM-controlled, within-subjects, crossover experimental design. Eighteen young adults completed a tACS condition and a SHAM condition on two different days in counterbalanced order with a week washout period between days. Transcranial magnetic stimulation (TMS) was utilized to assess excitability of the contralateral right M1 while tACS was delivered to the left M1. TMS was administered in five test blocks (termed Pre, D5, D10, D15, and Post) relative to a 20 min application of tACS (70 Hz, 1 mA current strength). The Pre and Post TMS test blocks were conducted before and immediately after tACS was applied to the left M1, whereas the TMS test blocks performed during tACS were completed at time points starting at the 5, 10, and 15 min marks of the 20 min stimulation period. The primary dependent variable was the 1 mV motor evoked potential (MEP) amplitude. MEP data were analyzed with a 2 condition (tACS, SHAM) × 5 test (Pre, D5, D10, D15, Post) within-subjects ANOVA. Results: The main effect for condition (p = 0.704) and condition × test interaction (p = 0.349) were both non-statistically significant. There was a significant main effect for test (p = 0.003); however, post hoc analysis indicated that none of the pairwise comparisons were statistically significant. Conclusions: Overall, the findings indicate that tACS applied to the left M1 does not significantly modulate contralateral right M1 excitability during or immediately after stimulation, at least when utilizing the present tACS parameters. Full article

Workplace integration in hierarchical collectivist societies is shaped by structured social mechanisms rather than collectivist values alone. While collectivism is often assumed to foster inclusiveness, its structural manifestations regulate workplace inclusion through feedback loops of hierarchical loyalty, trust building, and kinship-based exclusivity. This study employs causal loop diagrams (CLDs) to conceptually map how cultural structures regulate workplace inclusion—not to assert empirical causality, but to illustrate the culturally grounded feedback loops in Indonesia and the Philippines. The findings identify the reinforcing loops that sustain hierarchical exclusivity in Indonesia and a counterbalancing loop that facilitates immediate kinship-based trust in the Philippines. By conceptualizing workplace inclusion as an emergent property of interdependent social mechanisms, this study highlights how structured exclusivity stabilizes hierarchical workplaces while limiting adaptability. Unlike frameworks that treat collectivism as a static cultural trait, CLDs provide a dynamic lens to analyze how workplace inclusion evolves through structured feedback loops—revealing how structured exclusivity in collectivist systems governs trust, inclusion, and legitimacy not through ideology alone, but through relational sponsorship, time-dependent trust, and group-based gatekeeping. These insights contribute to cross-cultural management and organizational studies by demonstrating how structured exclusion functions as a self-reinforcing mechanism. The findings have implications for multinational corporations, policymakers, and organizational leaders seeking to design adaptive strategies for workplace integration in hierarchical collectivist environments. While both countries are analyzed, Indonesia serves as the primary site of investigation, with the Philippines providing a contrast to illuminate structured exclusivity mechanisms in hierarchical collectivist contexts. Full article

Background/Objectives: High-intensity functional training (HIFT) combines multijoint aerobic and resistance exercises. Despite its popularity, limited research has investigated dietary or supplementation strategies to enhance adaptations to HIFT. Hence, this study aimed to examine the effects of egg white and whey protein supplementation during HIFT on physical performance in trained individuals. Methods: Thirty recreationally trained volunteers (20 males, 10 females), aged 23–55, underwent 6 weeks of HIFT (three times/week) while receiving 0.6 g/kg/day of egg white protein, whey protein, or maltodextrin (placebo) in a researcher-blinded, randomized, triple-crossover, and counterbalanced design, with 2 weeks of washout between supplements. Participants followed isoenergetic diets providing 1.0 g/kg/day of protein. Before and after each intervention, VO₂max, the maximal strength (1 RM) and force–velocity relationship of shoulder press, the peak torque and strength endurance of knee extensors and flexors, and the strength endurance of core muscles were measured. The training session load was monitored during each intervention period’s first and last weeks. Data were analyzed by three-way ANOVA (supplement × time × sex), with repeated measures on supplement and time. Results: The duration, energy expenditure, training load score, and cardio load of each training session increased from the beginning to the end of each training period by 2–11% (p < 0.05). The 1 RM of shoulder press and strength endurance of core muscles increased by 3–6% (p < 0.001). Protein supplementation did not affect any of these outcomes. Conclusions: Short-term HIFT improved exercise capacity, upper-body strength, and core endurance. However, increasing protein intake from 1.0 to 1.6 g/kg/day did not further enhance performance. Full article

Background/Objectives: Thrombocytopenia–absent radius (TAR) syndrome is a rare genetic disorder characterized by the bilateral absence of the radius and thrombocytopenia, often leading to functional limitations and gait asymmetries. Prosthetic devices are sometimes employed to improve mobility and posture, but their impact on gait mechanics in pediatric patients remains poorly understood. Methods: The methodology used is based on a study that evaluated the gait parameters of a 10-year-old child with TAR syndrome under static and dynamic conditions, both with and without the use of a custom-designed upper limb prosthesis. The analysis focused on assessing the prosthesis’s impact on gait symmetry and biomechanics. A key aspect of the methodology involved studying the distribution of pressure forces on the ground during walking using the FreeMed EXTREME Maxi baropodometric platform. Results: Gait analysis demonstrated asymmetries between the left and right feet. In the absence of the prosthesis, the patient exhibited excessive forward loading and uneven pressure distributions. The use of a custom prosthesis, particularly with counterbalancing features, improved gait symmetry but led to increased reliance on the left foot. This foot experienced higher pressures (738–852 g/cm²) and longer ground contact times (690–865 ms) compared to the right foot (619–748 g/cm² and 673–771 ms). The left foot displayed elevated forefoot pressures (61–65%), while the right foot bore weight laterally (66–74%). Conclusions: The custom prosthesis influenced gait mechanics by redistributing plantar pressures and modifying ground contact times, partially improving gait symmetry. However, compensatory strategies, such as increased loading on the left foot, could contribute to musculoskeletal strain over time. Individualized rehabilitation programs and prosthetic designs are essential for optimizing gait mechanics, improving mobility, and minimizing long-term complications in TAR syndrome patients. Full article

Background/Objectives: The purpose of the study was to investigate the effects of a priming training session with either a light or heavy load snatch and clean pulls on weightlifting performance. Methods: Twelve well-trained weightlifters (seven males and five females) participated in the study. The athletes followed a counterbalanced study design comparing three treatments, including a day of rest (control) and two priming sessions involving two different weightlifting derivatives—the snatch and the clean pulls—which were performed either with 80% of the one-repetition maximum (1-RM) (LP) or with 110% of the 1-RM (HP). Twenty-four hours later, the 1-RM strength test for the snatch and clean and jerk, as well as the barbell kinematic characteristics at 100% of the 1-RM in the snatch and clean and jerk, were measured. The rate of perceived exertion (RPE) was measured following the priming sessions. Results: Performance in snatch remained unchanged following the LP and HP. However, performance in the clean and jerk increased significantly by 3.1% following the HP compared to the control. No significant differences were observed in barbell kinematics. The RPE was significantly higher for HP compared to LP. Conclusions: These results suggest that an HP performed 24 h prior to the 1-RM evaluation in weightlifting may have significantly increased performance in the clean and jerk. These changes may not be explained by barbell kinematics. Full article

The potential of laser-based powder bed fusion (L-PBF) technology for producing functional components relies on its capability of maintaining or even improving the mechanical properties of the processed material. This improvement is associated with the microstructure resulting from the high thermal gradient and fast cooling rate. However, this microstructural advantage may be counterbalanced by the lack of full density, which could be tolerated to a certain degree for applications such as biomedical implants and medical equipment. In this study, medical-grade 316L stainless steel specimens with porosities ranging from 1.7 to 9.1% were additively manufactured by L-PBF using different combinations of laser power and scanning speeds. Tribological properties were evaluated by pin-on-disc testing in dry conditions against a silicon nitride test body and analyzed in the context of microstructural characterization by optical and electron microscopy. The results reveal that higher porosity allows for a diminishing wear rate, which is explained by the capacity of the pores to retain wear debris related with the three-body abrasion. This research provides practical insights into the design of medical wear-resistant components, thereby enhancing our understanding of the potential of L-PBF in the fields of materials science and biomedical engineering. Full article

The purpose of this study was to compare the mechanical properties of a non-cushioned minimalistic shoe and cushioned shoe during walking at 6 and running at 10 and 14 km∙h⁻¹ in habituated female runners. Twelve habituated female runners completed two trials (cushioned shoe vs. minimalist shoe) with three within-trial speeds (6, 10, and 14 km∙h⁻¹) in a counter-balanced design. Flexible pressure insole sensors were used to determine kinetic variables (peak vertical impact force, average loading rate, active vertical peak force, time to active peak vertical force, and impulse) and spatiotemporal variables (stride duration, cadence, ground contact time, swing time, and time to midstance). Cushioned running shoes exhibited greater energy absorption (690%), recovered energy (920%), and heat dissipation (350%). The cushioned shoes significantly reduced peak vertical impact (~12%) and average loading rate (~11%) at running speeds 10–14 km∙h⁻¹. However, these effects were not observed during walking, nor did the cushioned shoes influence peak active force, impulse, stride duration, ground contact or swing time. Cushioned running shoes provide significant benefits in energy absorption, energy recovery, and heat dissipation, which decrease impact-related forces and loading rates in female runners without changing the spatiotemporal variables of gait. Full article

Backgrounds and Objectives: Obesity presents a significant global public health challenge and is associated with declines in both general and food-related inhibitory control, crucial for maintaining a healthy weight and preventing obesity progression. An increasing body of research suggests that acute aerobic exercise may improve inhibitory function. However, the effects and underlying mechanisms of acute aerobic exercise on both general and food-related inhibition in obese adults remain unclear. This study aimed to explore the potential impacts and underlying neuroelectronic mechanisms of a single session of aerobic exercise at varying intensities on general and food-related inhibitory functions among young adult males with obesity. Design: A within-subject design comprising three sessions (control, low-intensity exercise, moderate-intensity exercise) × three picture types (high-calorie food, low-calorie food, neutral picture) was employed. Methods: Eighteen young adult males with obesity [body mass index (BMI): 34.60 ± 4.21 kg/m², aged 24.50 ± 5.13 years (Mean ± SD)] were recruited. They participated in three intervention sessions: acute aerobic exercise at low [40–50% maximal Heart Rate (HR_max)], moderate (65–70% HR_max), and a control session (sitting rest), separated by five-day intervals in a counterbalanced order. Following each session, participants performed a food-related Go/No-go task, and EEG recordings (N2 and P3 components) were conducted within 15 min. Results: Moderate-intensity exercise elicited larger N2 amplitudes compared to the control session across different picture types and task conditions. However, there was no significant effect on behavioral indicators or P3 amplitude across sessions. Additionally, food stimuli (both high- and low-calorie) resulted in lower No-go accuracy and smaller N2 amplitudes compared to neutral stimuli. Conclusions: Acute moderate-intensity exercise might influence general and food-related inhibitory function in obese individuals at the neuroelectric stage, potentially by enhancing attentional resources for managing cognitive control and conflict detection. Moreover, reduced N2 amplitudes and No-go accuracy in response to food stimuli compared to non-food stimuli indicate a diminished ability to allocate attentional and neural resources to manage food-related conflicts. However, due to the relatively small sample size, caution is advised when generalizing these findings to the broader population. The pilot test indicated that obese participants had difficulty sustaining high-intensity exercise at 80–90% of their maximum heart rate for a continuous or 20 min period, highlighting potential challenges in exercise adherence at high intensities within this population. Future research is needed to utilize interdisciplinary approaches and multimodal technologies to clarify how exercise influences food-related cognition, appetite regulation, and brain mechanisms in obesity, aiming to better contribute to the prevention and treatment of obesity. Full article

Background: The effects of handlebar width on female cyclists are understudied; therefore, it is necessary to find an optimal handlebar width for women based on anatomical features. Methods: Ten healthy women participants whose muscle activity and movements were measured using four kinds of handlebar widths were observed using EMG and 3D motion analysis systems. Participants cycled at a constant cadence and power output using different handlebar widths in a counterbalanced order. The kinematic results and muscle activation, as a consequence of using different handlebar widths, were compared using a one-way repeated measures ANOVA (α = 0.05). Results: It was discovered that using a medium-width handlebar not only resulted in significantly lower bicep activation compared to narrow and self-selected widths, but also resulted in less triceps and latissimus dorsi activation compared to the self-selected width. Regarding kinematics, using a medium-width handlebar significantly reduced hip ROM, while using a narrow handlebar led to greater hip adduction. Conclusions: Cyclists are advised to use a handlebar width that matches their shoulder width, since this may avoid muscle fatigue while also allowing for better hip posture. However, commercial models are usually wider than female shoulders. Thus, these results provide insights useful for future handlebar design. Full article

Background/Objectives: Galvanic vestibular stimulation (GVS) integrated into virtual reality (VR) environments enhances immersion and mitigates cybersickness. It is well known that GVS can affect standing balance. Most studies have investigated the effects of GVS in VR in seated conditions. The purpose of this study was to evaluate the impact of joint GVS and VR with moving visual stimulus on standing balance. Methods: Using a repeated measures counter-balanced design, motion sickness, postural sway, and velocity utilizing the center of pressure (COP) along the mediolateral (ML) and anteroposterior (AP) axes were obtained in 18 subjects during optokinetic (OPK) stimulus (black and white vertical bars moving from left to the right) in VR across three interventions: GVS in the same direction of visual stimulus—left to right ear (Positive GVS), GVS in the opposite direction of visual stimulus—right to left ear (Negative GVS), and without GVS (Null GVS). Motion sickness symptom scoring was obtained using the Pensacola Diagnostic Index. Results: The PDI score was increased significantly in the Negative GVS. The root mean square and sway range of COP along ML was greater during the Positive GVS and Negative GVS than the Null GVS, while, along AP, it was only greater during Negative GVS. During Positive GVS, mean positive and negative peak velocities, only in ML, were increased and decreased, respectively. During Negative GVS, only negative peak velocities in both ML and AP directions were decreased. Conclusions: This research highlights the importance of testing combined VR and GVS to assess standing balance while mitigating cybersickness. Full article

Background: Caffeine is a widely recognized ergogenic aid for enhancing exercise performance. However, its effect on throwing performance has been less studied, yielding contradictory results. Objectives: The main aim of the study was to analyze the potential ergogenic effects of a moderate dose of caffeine (3 mg·kg⁻¹ body mass) on vertical jump performance and throwing distance during a simulated competition in trained discus and hammer throwers. Methods: In a randomized, counterbalanced, and repeated measures design, 14 well-trained throwers (9 hammer throwers and 5 discus throwers; age 24.8 ± 6.3 years old, training 14.9 ± 5.0 h per week, competing experience 10.5 ± 6.1 years) performed a countermovement jump (CMJ) test, a modified throw, and a complete throw after the ingestion of 3 mg·kg⁻¹ body mass of caffeine or a placebo. Each participant performed three maximal-effort valid modified throws of his/her respective event (i.e., hammer or discus throw), plus three maximal-effort valid official throws (up to five tries, respectively, in case any attempt was called as foul). Throwing distance was measured according to World Athletics regulations using a metal tape, while release speed was assessed with a radar device. After the performance measurements, participants completed a form about side effects prevalence. Results: Caffeine, compared to placebo, increased throw distance (3.0 ± 5.1%, p = 0.048) and speed release (5.7 ± 8.7%, p = 0.03) for the complete throw, and distance (3.6 ± 4.4%, p = 0.01) and speed release (4.8 ± 7.4 %, p = 0.01) for the modified throw. Caffeine ingestion did not significantly improve jump height (1.1 ± 4.3%, p = 0.28), although it improved force and power on braking and the propulsive phases of the CMJ (p < 0.05). Caffeine only increased the prevalence of activeness (p < 0.05). Conclusions: An acute moderate dose of caffeine enhanced hammer and discus throw performance in well-trained throwers during a simulated competitive setting, with minimal adverse side effects. Full article