Search Results (726)

This study examined whether the Ringelmann and Köhler effects emerge in adolescent rowing by assessing how crew size influences performance, physiological responses and perceived exertion in youth rowers aged 14–17 years. A total of 136 competitive rowers (mean age = 15.79 ± 1.14 years) completed four three-minute maximal-effort trials on a rowing ergometer under four conditions: individual trials, two-person crews, four-person crews and eight-person crews. Objective performance indicators, including stroke rate, heart rate and perceived exertion (Borg scale), were recorded. Repeated-measures ANOVA indicated that objective performance indicators (distance and power output) remained largely stable across conditions and age groups, although some isolated and non-systematic differences with large intra-subject effect sizes emerged in the younger category (14–15 years), particularly in the two-person crew condition. In contrast, the stroke rate differed consistently across crew sizes, with higher values observed in the eight-person crew condition in both age groups. Cardiovascular responses showed minimal and transient variation between conditions. Perceived exertion differed markedly by age, with older rowers (16–17 years) reporting significantly higher effort during individual trials compared with crew-based conditions, without corresponding gains in objective performance. Overall, although crew size influenced the regulation and perception of effort, the findings do not provide support for a consistent expression of either the Ringelmann or Köhler effects in adolescent rowing, as no systematic performance losses or motivational gains among weaker crew members were evident. These results suggest that developmental differences in self-regulation and effort perception may play a more prominent role than crew size alone in shaping performance responses, with practical implications for training design and crew configuration in youth rowing. Full article

Understanding how contextual variables shape differences in match demands in youth football is essential for optimising performance and player development. Objective: This study aimed to compare physical and competitive performance according to playing position, match location, match result, and opponent quality in the physical and competitive performance of U21 football players from a professional Chilean club. Methods: Twenty male U21 players (19.2 ± 1.2 years) were monitored during 11 official matches using 10 Hz GPS devices (WIMU Pro™) and post-match Rating of Perceived Exertion (RPE). Variables included total distance (TD), high-speed running (HSR > 20 km/h), metres per minute (MM), accelerations/decelerations (N°AC/N°DC > 3 m·s⁻²), player load (PL), and peak velocity (PV). Contextual variables were classified by playing position, home/away, win/loss, and opponent quality (higher vs. lower rank). Results: Significant between-group differences were found across all contextual factors (p < 0.05). Midfielders (MFs) covered greater TD and reported higher RPE, while full-backs (FBs) and wingers (WGs) reached higher HSR and PV. Away and lost matches showed greater RPE, PL, and N°AC/N°DC, alongside more goals conceded. Facing higher-ranked opponents increased RPE and HSR but reduced explosive actions. Conclusions: Physical performance in U21 football is strongly modulated by contextual factors. Coaches should adjust training load and tactical strategies according to match conditions and positional roles to optimise adaptation and competitive readiness in developmental categories. Full article

Background: Obesity, defined as an abnormal accumulation of body fat, is becoming a global epidemic. Individuals with obesity may present with increased abdominal fat, which is associated with hypertension, altered respiratory mechanics, higher resting heart rate, and may contribute to an increased cardiovascular risk. Physiological parameters, such as heart rate, blood pressure, respiratory rate, and oxygen saturation, can change hours before the occurrence of a clinically relevant adverse event. Thus, physiological parameters can be considered good predictors of clinical deterioration. Obesity is also associated with physical dysfunctions that can impair physical performance. The non-pharmacological therapeutic strategy for the treatment of obesity involves lifestyle modifications, including a healthy diet and regular physical exercise. Whole-body vibration (WBV) exercise, a type of physical activity, has demonstrated benefits in several specific populations, including obese individuals. Objectives: The objective of this study was to evaluate the immediate effects of a single whole-body vibration (WBV) exercise session, consisting of 15 sets, using a vibration platform (VP) with alternating vertical or lateral displacement, on physiological parameters, perceived exertion, strength, and functionality in obese adults. Methods: Seventy-two obese adult participants were randomly divided into three groups (vertical group, alternating lateral group, and placebo group). Physiological parameters were assessed before, during, and after the intervention, in addition to perceived exertion, functionality, and muscle strength. Results: When comparing the results before and after the intervention, the heart rate–pressure product increased significantly in the alternating lateral group (p = 0.005), and heart rate increased significantly (p = 0.0001) and then decreased significantly (p = 0.030) only in the alternating lateral group. Post hoc analysis revealed a significant increase in perceived exertion in the lateral alternation group, from the period before the intervention to the 10th set (p = 0.006) and from the period before to the period after the intervention (p = 0.011). In the vertical group, a significant increase was observed from the period before the intervention to the 10th set (p = 0.020). Conclusions: In conclusion, considering all the findings of this study, whole-body vibration (WBV) exercise promoted some immediate changes in physiological parameters and perception of effort in obese adults. WBV exercise with the alternating vibration platform induced significant fluctuations in heart rate and increased the heart rate–blood pressure product, although with values within the normal range. Perception of effort increased in all groups. Considering the absence of discrepant changes in physiological parameters, impact on the cardiovascular system, and fatigue, the WBV exercise intervention in side-alternating or vertical vibration vibratory platforms can be considered a viable non-conventional exercise option for the obese population. Full article

Although green housing is widely regarded as an effective solution to energy and environmental challenges, its actual rate of adoption remains lower than expected. In the context of increasingly prominent sustainable development goals, promoting residents’ adoption of green housing has become a key issue in advancing sustainable transformation within the housing sector. Consequently, enhancing residents’ willingness to adopt green housing is critical to its broader diffusion. Drawing on diffusion of innovation theory, attitude theory, and perceived value theory, this study develops a multidimensional integrated model to identify factors influencing the adoption of green housing. The model examines how the innovation attributes of green housing and residents’ psychological evaluations jointly shape adoption intention. A questionnaire survey was conducted among 387 residents in Nanjing, China, and the data were analysed using partial least squares modelling. The results indicate that the five attributes derived from diffusion of innovation theory are significant antecedents of residents’ attitudes. Relative advantage, compatibility, trialability, and observability exert significant positive effects on residents’ attitudes toward adopting green housing, with relative advantage emerging as the most influential factor. Complexity has a negative, though comparatively weaker, effect on residents’ attitudes toward green housing adoption. Residents’ attitudes and perceived value are identified as significant predictors of green housing adoption intention. These findings contribute to a clearer understanding of residents’ green housing adoption intentions for both researchers and practitioners. More importantly, the study offers general policy and managerial implications for governments and developers seeking to enhance the uptake of green housing. Full article

Background. This study aimed to quantify differences in the internal training load (ITL) of an elite rink hockey (RH) team across days within and between three types of microcycles: pre-season, in-season regular, and in-season congested, to provide insights to optimise microcycle scheduling. Methods. One international-level male RH team comprising seven outfielders (29.6 ± 4.7 years; height, 178.9 ± 2.3 cm; body mass, 77.8 ± 5.7 kg) and one goalkeeper (32 years; height, 180.4 cm; body mass, 83.6 kg) was monitored for 21 microcycles. The ITL was assessed using the session rate of perceived exertion (sRPE) and quantified as time based on a triphasic classification commonly utilised in team sports: low-intensity training (LIT, <80% heart rate maximum (HRmax)), medium-intensity training (MIT, 80–90% HRmax), and high-intensity training (HIT, >90% HRmax). Generalized estimating equations were used to examine differences across within-microcycle training days and between seasonal phases, with linear mixed models applied as sensitivity analyses. Results. Across all phases, significant day-to-day variations in ITL were observed within microcycles (all p < 0.001), with both subjective (sRPE) and objective (LIT–HIT) ITLs progressively decreasing as match days (MDs) approached, showing moderate-to-large population-averaged effects with 95% confidence intervals consistently not crossing zero. The pre-season exhibited the highest overall ITL (p < 0.001), characterised by a substantially greater sRPE and increased time spent across all intensity zones, with the largest magnitudes observed for LIT and MIT compared with the in-season phases. Conclusions. Findings suggest that an international-level RH team progressively reduced the ITL as MDs approached with the highest loads scheduled earlier within microcycles. Moreover, the pre-season had the highest ITLs. This ITL distribution may provide useful guidance for RH coaches and support staff in optimising microcycle planning. Full article

Frailty in older adults is a multidimensional syndrome characterized by reduced physiological resilience and heightened vulnerability to adverse outcomes, yet conventional assessments remain largely clinic-based. This study evaluated the feasibility and explanatory utility of smartphone-based digital lifelogs for assessing frailty in community-dwelling older adults. In a prospective observational study, 300 participants (mean age 73.30, SD 5.37 years) from three sites in Seoul, South Korea, used a custom mobile application for two weeks that passively collected sensor-derived gait speed, 30 s sit-to-stand counts, and daily and hourly step counts, alongside self-reported ratings of perceived exertion and subjective health. Frailty Index (FI) scores were computed, and Pearson correlations, hierarchical linear regression, and independent linear regression were applied to examine associations and model explanatory performance. Significant correlations were observed between FI and gait speed, sit-to-stand performance, daily step counts, perceived exertion, and subjective health. Incorporating digital lifelogs significantly improved explained variance in frailty beyond clinical indicators (ΔR² = 0.183), with gait speed and daily step counts emerging as key predictors. A model including only digital lifelogs also significantly associated with frailty (R² = 0.288). These findings suggest that smartphone-based lifelogging offers a feasible, practical, and informative method for two-week monitoring and cross-sectional assessment in community settings. Full article

Using efficient voice alarms to ensure safe evacuation is important during emergencies, especially for the elderly. Factors that have important influence on speech perceptions have been investigated for several years. However, relatively few studies have specifically explored the key factors influencing perceptions of voice alarms in emergency situations. This study investigated the combined effects of speech rate (SR), signal-to-noise ratio (SNR), and reverberation time (RT) on older people’s perception of voice alarms. Thirty older adults were invited to evaluate speech intelligibility, listening difficulty, and perceived urgency after hearing 48 different voice alarm conditions. For comparison, 25 young adults were also recruited in the same experiment. The results for older adults showed that: (1) When SR increased, speech intelligibility significantly decreased, and listening difficulty significantly increased. Perceived urgency reached its maximum at the normal speech rate for older adults, in contrast to young adults, for whom urgency was greatest at the fast speech rate. (2) With the rising SNR, speech intelligibility and perceived urgency significantly increased, and listening difficulty significantly decreased. In contrast, with the rising RT, speech intelligibility and perceived urgency significantly decreased, while listening difficulty significantly increased. (3) RT exerted a relatively stronger independent influence on speech intelligibility and listening difficulty among older adults compared to young adults, which tended not to be substantially moderated by SR or SNR. The interactive effect of SR and RT on perceived urgency was significant for older people, but not significant for young people. These findings provide referential strategies for designing efficient voice alarms for the elderly. Full article

Objective: The purpose of this study was to explore the effects of an acute dose of cannabidiol (CBD) on physical and mental health, as well as running performance in a group of runners. Methods: This study used a randomized, cross-over design where individuals were given CBD (CBD-T) or placebo (PLA-T) capsules on two separate occasions. During their first visit, the subjects consumed 300 mg of either placebo or CBD capsules and were then instructed to sit quietly for 2 h. Then, participants filled out a State Trait Anxiety Inventory (STAI) and completed measures of resting systolic (SBP) and diastolic blood pressure (DBP), heart rate (HR), blood lactate (BL), and heart rate variability (HRV). Next, participants completed a 2-mile treadmill run as fast as possible. During each run, HR, rating of perceived exertion (RPE), and BL were measured during and after the run. Participants completed a gastrointestinal (GI) symptom questionnaire immediately after the 2-mile time trial. Results: Participants (N = 12; 4 males, 8 females) averaged 25.5 years ± 3.34 years of age. Mean CBD-T reported increased feelings of calm (21% p = 0.04) and relaxed (22%, p = 0.02) when compared to PLA-T. There were no differences in the severity of GI symptoms, SBP, DBP, or HRV between the treatments. The CBD-T experienced an 8% reduction in average RPE at mile 1 of the run compared with PLA-T (p = 0.05). There was no significant difference in run performance time. Conclusions: An acute dose of CBD (300 mg) taken 2 h before a 2-mile run may potentially benefit runners in shorter distance competitions by increasing calm and relaxed feelings and reducing perceived effort at the halfway point without impairing performance or increasing gastrointestinal upset. Full article

Background/Objectives: To examine the safety and clinical applicability of a newly developed outdoor-simulated interactive indoor cycling device as a potential exercise modality for cardiac rehabilitation (CR) in patients with cardiovascular disease (CVD). Methods: Twenty patients with CVD with low-to-moderate cardiovascular exercise risk performed a symptom-limited cardiopulmonary exercise stress test (CPET) using a modified Bruce protocol to obtain peak cardiopulmonary responses. After a 30–60 min rest, they rode the outdoor-simulated interactive indoor cycling device for 10 min with continuous gas exchange and electrocardiography monitoring. The treadmill-based CPET results were compared with those from the cycling device, focusing on key cardiopulmonary variables, such as VO₂, HR, METs, and Rating of Perceived Exertion (RPE). Results: The 20 male participants had a mean age of 56.1 years. When treadmill peak values were used as reference, the cycling device elicited responses corresponding to moderate-to-vigorous intensity. In subgroup analysis, treadmill-derived peak VO₂, peak HR, and peak MET values were significantly lower in patients aged ≥60 years compared with those aged <60 years. However, no significant differences were observed in cycling-derived values between the two groups, suggesting that cycling may represent a relatively higher-intensity exercise compared with treadmill in older patients. No significant adverse cardiac events were observed during cycling. Conclusions: The outdoor-simulated interactive indoor cycling device delivered exercise intensity within the therapeutic range recommended for CR in patients with CVD. Furthermore, it appeared to elicit relatively higher exercise intensity in older patients, supporting its potential as a safe and effective alternative exercise modality for CR. Full article

Beyond utilitarian purpose, architecture possesses profound aesthetic value, serving not only as structures to inhabit but as spaces to be perceived, interpreted, and appreciated. Unity and variety are among the predictors that influence aesthetics, traditionally viewed as oppositional but jointly predictive of aesthetic preference. The present research investigates how unity and variety jointly predict aesthetic preference in the domain of Chinese carved windows and how these relationships change from isolated elements to window–background compositions. Two quasi-experimental studies were conducted. Study 1 asked participants to rate ten digitally rendered Chinese windows on unity, variety, and aesthetic preference. Study 2 used the same ten windows embedded in either a stylistically congruent Chinese background or an incongruent Western background. Across both studies (N = 797), results showed that unity and variety were negatively correlated yet both positively associated with aesthetic preference, with unity exerting the stronger predictive influence. The trade-off between unity and variety decreased once windows were placed in backgrounds, and stylistically incongruent Western backgrounds reliably suppressed perceived unity and inflated perceived variety. The findings are consistent with the Unity-in-Variety principle and highlight how architectural context influences unity–variety judgments. The studies provide strategies toward a more nuanced, architecture-specific understanding of unity and variety in aesthetic preference. Full article

This study compared the external [movement load (ML)] and internal [rating of perceived exertion (RPE), mean and peak heart rate (HRmean, HRpeak)] loads, performance and enjoyment between time-matched (~12 min) traditional (TRAD) and small-sided game (SSG) warm-ups in youth basketball players. Using a counterbalanced crossover design, 24 male players (16.0 ± 0.1 years) performed both warm-up types after reporting fatigue (ROF) and completing an 8 min standardized pre-warm-up. Before and after each warm-up, players completed 20 m sprint and countermovement jump (CMJ) tests; enjoyment (ENJ) was assessed post-warm-up. No significant differences were found between warm-ups for ROF (p = 0.053), RPE (p = 0.259), or HRmean (p = 0.053). However, SSG induced a higher HRpeak than TRAD (p = 0.001), while ML was greater in TRAD (p < 0.001). No interaction, time effect, or typology effect emerged for performance in sprinting and change of direction, although CMJ was higher after TRAD (p = 0.047). Enjoyment did not differ significantly (p = 0.066), although with a large effect size (r = 0.612). The greater ML in TRAD may reflect more dynamic basketball actions compared with SSG, which emphasized static tasks (e.g., screening, boxing out) yet produced higher HRpeak. Coaches may consider SSG warm-ups to replicate game-specific conditions while controlling the external load and maintaining adequate physiological preparation. Full article

To investigate age-related differences in preferred air speed in warm conditions, experiments were conducted in a climate-controlled chamber. 24 young and 24 elderly participants were tested in windless and preferred wind conditions. A resting metabolic rate (RMR) prediction model based on body composition was proposed to examine the effects of individual differences on preferred air speed. Results showed that the elderly exhibited lower RMR than the young, but their mean preferred air speed was 1.3 m/s, significantly higher than that of the young (0.9 m/s), corresponding to their higher mean skin temperatures. Preferred airflow effectively reduced thermal sensation and perceived sweating, thereby improving thermal comfort and airflow acceptance. During airflow exposure, mean skin temperature decreased, while LF/HF index of heart rate variability and skin conductance level increased, indicating enhanced sympathetic activity. These findings suggest that reduced sweat gland function and evaporative heat dissipation cause the elderly to require higher air speeds to achieve thermal neutrality. Their reduced thermal sensitivity further highlights the need for more precise environmental control. RMR exerted a more pronounced influence on the preferred air speed among the elderly, underscoring its significance in designing thermally adaptive environments for aging populations. Full article

Background/Objectives: Creatine monohydrate (CrM) supplementation is well-established for enhancing physical performance and accelerating recovery in several sporting contexts. However, beyond these traditional performance benefits, its effects on sleep metrics and cognitive function have not been thoroughly investigated. This investigation aimed to determine the effect of a loading phase of CrM on sleep metrics, physical performance, psycho-cognitive aspects, and recovery in physically active men. Methods: In a randomized, double-blind, placebo-controlled crossover design, 14 physically active men ingested 20 g/day of CrM or placebo (PL) for 7 days, during which their habitual exercise routines were maintained and standardized across both intervention phases. Sleep metrics were monitored throughout the interventions using wrist-worn actigraphy. On the day following the completion of each supplementation phase, participants rated their sleep quality using the Sleep Subjective Quality (SSQ) scale, and the Hooper questionnaire was used to monitor participants’ well-being status. Physical performance was assessed using the 5 m shuttle run test (5mSRT), which measured total distance (TD), best distance (BD), performance decrement (PD), fatigue index (FI), and the rating of perceived exertion (RPE). Affective valence was determined using the feeling scale (FS) and cognitive function was evaluated using the digit cancellation test (DCT). Recovery and muscle soreness perceptions were evaluated at multiple time points (pre-exercise, 5 min, 24 h, 48 h, and 72 h post-exercise) using the perceived recovery status (PRS) and the delayed onset muscle soreness (DOMS) scales, respectively. Results: During the supplementation, CrM improved sleep quality compared to PL, as measured with the SSQ scale (d = 0.81, p = 0.009), and was associated with an earlier in-bed time (r = 0.60; p = 0.026). However, CrM did not affect sleep latency (t = 0.98; p = 0.35), sleep efficiency (t = 0.018; p = 0.98), or total sleep time (t = 0.25; p = 0.81). After the supplementation phase, CrM resulted in significantly lower muscle soreness scores, as measured by the Hooper questionnaire (d = −0.59; p = 0.046), improved cognitive performance on the DCT (d = 0.77; p = 0.013), and enhanced TD (r = 0.88; p < 0.001) and BD (r = 0.76; p < 0.05) during the 5mSRT. However, CrM did not significantly affect other exercise-related measures such as RPE, fatigue index (FI), or performance decrement (PD) during the 5mSRT, nor did it alter other subjective recovery scales compared to PL, up to 72 h following the end of the supplementation phase (all p > 0.05). Conclusions: A 7-day CrM loading protocol improved subjective sleep quality during the supplementation phase, enhanced cognitive performance, and increased physical output during high-intensity intermittent exercise. CrM also reduced muscle soreness, but did not significantly affect objective sleep parameters, or recovery markers up to 72 h post-exercise. These findings suggest that CrM may offer additional benefits beyond its traditional ergogenic role. Trial Registration: This trial was registered on 18 September 2023 at the Pan African Clinical Trials Registry (PACT) (identifier: PACTR202309597156293). Full article

As data product transactions become increasingly standardized, the operational strategies of data product manufacturers and service providers play a pivotal role in shaping market outcomes. This study develops a game-theoretic framework that incorporates dynamic data updates under alternative power structures to examine the equilibrium performance of pricing, demand, technological investment, update rates, and promotional effort. The results indicate that optimal prices under Stackelberg leadership exceed those in the Nash game, whereas demand, technological investment, update frequency, and promotion are consistently higher in the Nash setting. The effects of these decisions are moderated by end-user preference heterogeneity: when users exhibit stronger promotion preferences, service-provider leadership generates superior outcomes, while stronger quality preferences favor manufacturer leadership. Demand preferences and cost coefficients significantly influence profitability—enhanced preferences improve the leader’s returns, whereas high technological and promotional costs suppress profits for both parties. Cost savings in dynamic updates and increases in perceived value exert strong positive effects on market competitiveness, while higher update investment and data acquisition costs exert negative effects. Overall, this study deepens the theoretical understanding of how power structures interact with dynamic updating and user preferences, providing analytical insights and decision support for optimizing operational strategies in data product markets. Full article

Caffeine, a nervous system stimulant, and sodium bicarbonate, a metabolic buffer, have been shown to improve performance in high-intensity, particularly aerobic, exercises. This randomized, double-blind, placebo-controlled, crossover study compared the acute effects of caffeine and sodium bicarbonate on chest press (CP) and knee extension (KE) performance. Twelve resistance-trained young adults (seven females) completed three testing sessions during which they consumed caffeine (0.003 g/kg of body weight), sodium bicarbonate (0.3 g/kg of body weight), or placebo at 120, 90, and 60 min prior to testing. Testing consisted of six sets of CP and KE for as many repetitions as possible at 70% of the participants’ 1-repetition maximum load. A 60 s recovery between sets, and 2 min recovery was allocated between exercises. Blood pressure and blood lactate were recorded pre-, mid-, and post-test. Heart rate, ratings of perceived exertion (RPE), repetitions, and electromyography (EMG) were recorded for every set. No significant differences were found under any condition for RPE, EMG, and KE repetitions. A main effect for groups revealed was increased CP repetitions with sodium bicarbonate (7.42; 95%CI: 6.8–7.9) versus caffeine (6.7; 95%CI: 6.1–7.3) and control (7.1; 95%CI: 6.4–7.6) conditions. However, post hoc analysis did not achieve significance. Diastolic blood pressure was significantly (p = 0.03) greater with caffeine (79.2 mmHg; 95%CI: 74.6–83.7) than with sodium bicarbonate (72.7 mmHg; 95%CI: 67.5–77.9) and control (74.5 mmHg; 95%CI: 71.7–77.3). Females had significantly lower blood lactate measurements, higher CP repetitions, and lower heart rates, despite similar resting heart rates between the sexes. Caffeine (0.003 g/kg) or sodium bicarbonate (0.3 g/kg) did not provide acute ergogenic effects on CP or KE strength endurance (six sets of CP and KE at 70% 1-repetition maximum load) performance in young adult women and men. Full article