Low-intensity Movement Research Articles

Influence of Brazilian Jiu-Jitsu Belt Graduations on the Performance of Elite Female Combat Athletes

Abstract Introduction. In Brazilian Jiu-jitsu (BJJ), match durations are determined by belt rank according to the rules. However, a detailed understanding of the dynamics in female matches across belt levels is lacking. Gaining this insight could refine training, better meeting the needs of female athletes at each progression stage. Therefore, this study aims to conduct a comparative time-motion analysis of combat phases among elite female practitioners across different belt ranks. Material and Methods. The sample was composed of White (n = 60), Blue (n = 150), Purple (n = 108), Brown (n = 56), and Black (n = 48) belts. All combats were analyzed using a BJJ time-motion protocol according to the sequential actions of the combats (i.e., approach, gripping, attack, defense, transition, guard, mount, side control, low-intensity movements, and total time), p ≤ 0.05. Results. The main results indicated longer time in the black belt division vs. white and blue belts in low-intensity movements [170(63;311.6) s vs. 75.1(39.7; 201.9)s, and 93.1 (34.2; 168.7)s], defensive actions [31(10.2;76.6)s vs. 12.2(50.5; 22.4)s, and 22.4(11; 49.4)s], and approach actions [9.1(5.5;23.3)s vs. 5.2(2.5; 9.9)s, and 4.8(1; 12)s], respectively. Conclusions. No effects were observed in combat-determining domain actions such as gripping, transition actions, side control, and mount, even with differences in the rules, suggesting a progressive reduction in intensity accompanying the increase in total combat time as the rank in BJJ increases.

Intermittent low-intensity and moderate-intensity exercise effects on cognition in community-dwelling older adults: a pilot study exploring biological mechanisms.

To examine the cognitive benefits of 6 months of prescribed intermittent exercise (10-min bouts totaling 150 weekly minutes) in community-dwelling older adults, comparing effects of low-intensity movement (LIM) and moderate-intensity aerobic exercise (aerobic exercise; AE) training; and exploring biological mechanisms of exercise-related cognitive improvement. Twenty-five adults (>60 years old) participated in a 6-month controlled trial and were randomized into LIM or AE intermittent training. Cognition was assessed using a neuropsychological test battery including the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), California Verbal Learning Test, 2nd Edition (CVLT-II), and Delis-Kaplan Executive Function System (D-KEFS). Neuroimaging measures were collected using a 7 T human MRI scanner. Serologic neurotrophic and inflammatory factors were analyzed using Luminex multiplex assays [brain derived neurotrophic factor (BDNF); vascular endothelial growth factor (VEGF)]; interleukin-6 (IL-6), C-reactive protein (CRP), plasminogen activator inhibitor (PAI-1). LIM and AE intermittent training had dissociable effects on cognition, with LIM resulting in improved learning and memory and AE resulting in improved executive functioning. Intervention groups differed on change in cognitive performance on CVLT-II learning and D-KEFS trail making test. Increase in right dorsolateral prefrontal cortex (DLPFC) surface area was linked to executive improvement (i.e., phonemic fluency) regardless of intervention group. A decline in circulating PAI-1 was linked to learning and memory improvement in response to LIM over 6 months. Moderate-intensity AE and LIM intermittent training likely have distinct cognitive benefits, though low-intensity activity is often included as a control group in exercise trials in aging.

The Dynamics of Victory: Exploring the Movement Patterns of Female Brazilian Jiu-Jitsu Athletes in Win-ning and Losing Combats through Time-Motion Analysis

In the quest to understand the dynamics of female Brazilian Jiu-Jitsu (BJJ) combats, this research delves into the world of winning and losing. By comparing time-motion analysis based on different outcomes, our objective was to unveil the movement patterns of victory. Our sample included 209 winning (W) versus 209 losing (L) female international BJJ combats, presenting a comprehensive picture of the combat landscape. Through time-motion analysis, we explored various BJJ combat phases, such as approach, gripping, transition, side control, mounting, attack, defense, low-intensity movement, and total time. The statistical results highlight significant differences between winners and losers in key aspects of the combats. Notably, side control (W= 47.7 [27.8; 96.5]s vs. L= 27.3 [20.3; 41.9]s), mount (W= 40.0 [16.6; 85.9]s vs. L= 15.9 [6.1; 25.6]s), attack (W= 50.1 [28.6; 86.7]s vs. L= 16.6 [7.7; 35.7]s), defense (W= 14.6 [6.6; 38.2]s vs. L= 38.8 [17.7; 77.0]s), and low-intensity movement (W= 55.9 [23.4; 132.2]s vs. L= 111.5 [58.7; 225.6]s) revealed differences between the winners and losers. The implications extend to sports psychology and judo training, providing knowledge for enhancing performance, optimizing training programs, and making strategic decisions during combat. Keywords: sports psychology, technical-tactical analysis, task performance and analysis, judo, martial arts.

Effects of Virtual Reality Pilates Training on Duration of Posture Maintenance and Flow in Young, Healthy Individuals: Randomized Crossover Trial.

This study explored the use of virtual reality (VR) technology to enhance the effectiveness and duration of low-intensity movements and postures in Pilates-derived exercises. We postulate that by leveraging the flow state in VR, individuals can engage in these exercises for longer periods while maintaining a high level of flow. The purpose of this study was to compare differences in posture maintenance and flow between VR Pilates training and conventional Pilates training, and the correlation between the 2 factors. The 18 participants in each group received either VR training or conventional training and were switched to the other training type after a 2-day wash-out period. Each group performed Pilates movements in a VR environment and a conventional environment, divided into 4 types. After training sessions, participants were evaluated for flow using a self-report questionnaire. In addition, a sports video analysis program was used to measure the duration of posture maintenance in 2 video-recorded sessions. Repeated-measures ANOVA and correlation analysis were performed on the measured duration of posture maintenance and flow scores. In all cases, the statistical significance level was set at P<.05. Results for the duration of posture maintenance verification by type showed that simple behavior (F1,16=17.631; P<.001), upper body-arm coordination behavior (F1,16=6.083; P=.04), upper body-leg coordination behavior (F1,16=8.359; P<.001), and whole-body coordination behavior (F1,16=8.426; P<.001) all showed an interaction effect at P<.05. Flow (F1,16=15.250; P<.001) also showed an interaction effect. In addition, significant correlations were determined between duration of all types of posture maintenance and flow in the VR training group at P<.05. Our results indicate that VR Pilates training may be more useful than conventional Pilates training in improving the duration of posture maintenance and that it promotes a significantly higher degree of flow when compared with conventional Pilates training.

Hybrid Resnet and Bidirectional LSTM-Based Deep Learning Model for Cardiovascular Disease Detection Using PPG Signals

Hypertension is the major root cause of blood pressure (BP) which in turn causes different cardiovascular diseases (CVDs). Hence BP need to be regularly monitored for preventing CVDs since it can be diagnosed and controlled through constant observation. Photoplethysmography (PPG) is identified as an important low-cost technology for facilitating a convenient and effective process in the early detection of CVDs. Different cardiovascular parameters such as blood oxygen saturation, heart rate, blood pressure, etc can be determined using the PPG technology. These cardiovascular parameters when given as input to the deep learning model is determined to diagnosis CVDs with maximized accuracy to an expected level. In this paper, Hybrid ResNet and Bidirectional LSTM-based Deep Learning Model (HRBLDLM) is proposed for diagnosing CVDs from PPG signals with due help in supporting the physicians during the process of continuous monitoring. This deep learning model mainly concentrated on the diagnosis of stage 1 hypertension, stage 2 hypertension, prehypertension, and normal CVDs with maximized accuracy using PPG signals. The PPG signals determined from PPG-BP dataset for investigation were recorded using IoT-based wearable patient monitoring (WPM) devices during the physical activity that includes high intensity, medium and low intensity movements involved driving, sitting and walking. The experiments conducted for this proposed deep learning model using PPG-BP dataset confirmed a better classification accuracy of 99.62% on par with the baseline PPG-based deep learning models contributed for detecting CVDs.

Revisiting the physical activity paradox: the role of cardiorespiratory fitness in workers with high aerobic demands.

In contrast to leisure time physical activity, occupational physical activity may have adverse health effects-a phenomenon known as the "Physical activity paradox". Characteristics such as long duration, low intensity, static and restricted movement, body position and insufficient recovery are possible explanations as to why physical activity in the occupational context may "wear one out" rather than provide health benefits. We emphasise the role of low cardiorespiratory fitness as a potential contributor to the physical activity paradox, and present data suggesting that only 25% to 50% of Swedish workers in occupations with higher aerobic demands may have "sufficient" cardiorespiratory fitness to maintain good health during their employment. More research is needed to fully understand the complexity of the role of other confounding factors when examining the relationship between cardiorespiratory fitness and occupational workload. However, we believe that there is an increasing need for general awareness amongst Swedish authorities, employees and employers of the potential health consequences of low levels of cardiorespiratory fitness, especially among workers with high occupational workloads. Importantly, when developing interventions targeting the working situation and/or cardiorespiratory fitness levels among workers, researchers should actively involve the relevant population in the design of the study in order to maximize the effect of the interventions on health outcomes.

Effect of 8-week Shoulder External Rotation Exercise with Low Intensity and Slow Movement on Infraspinatus.

Generally, low-intensity training is recommended as selective training of the infraspinatus muscle. This study aimed to investigate whether an 8-week intervention of low-intensity, slow-movement, external rotation exercise of the shoulder led to an increase in muscle strength with shoulder external rotation and cross-sectional area (CSA) infraspinatus muscle. Sixteen healthy male volunteers were randomly assigned to the low-intensity and slow-movement (LS) group (N = 8) or the normal-intensity and normal-speed (NN) group (N = 8). The LS and NN groups performed shoulder external rotation exercises with low intensity and slow movement, and normal intensity and normal speed, respectively. The exercise session consisted of three sets of 10 repetitions, which were performed three times per week for 8 weeks. We measured the CSA of the infraspinatus and muscle strength of the shoulder external rotation before and after the 8-week intervention. A significant increase in infraspinatus CSA from baseline to 8 weeks was found in the LS group (7.3% of baseline) but not in the NN group. No significant differences were found in the muscle strength of shoulder external rotation. Our results suggest that low-intensity exercise of the infraspinatus is effective for muscle hypertrophy when performed with slow movement. This finding may help patients who should avoid excessive stress in the early phase of rehabilitation.

A study protocol for a randomized controlled trial to assess the efficacy of Baduanjin exercise on older adults with sarcopenia in China

BackgroundAccompanied by the decline of physiological functions, the decrease of physical activity, and comorbidities, older adults are susceptible to sarcopenia because of accelerated loss of muscle mass. Resistance training is recommended by different clinical practice guidelines. However, most older adults have difficulty in taking recommended high-load resistance training programs, and there are limited exercise options form them. Baduanjin, a traditional Chinese mind-body exercise with relatively low intensity and simple movements, has the potential benefits of improving physical functions and may be feasible in treating sarcopenia and preventing its adverse health outcomes in older patients. With the emergence of the concept of gut-muscle axis, this study aims to determine the efficacy of Baduanjin exercise on Chinese older adults with sarcopenia and explore its underlying mechanism.MethodsThis is a 24-week, assessor-blinded, randomized controlled trial. Individuals aged 60 to 84 years old will be screened for sarcopenia. 90 participants with sarcopenia will be enrolled and randomly assigned (1:1) into the Baduanjin exercise or resistance training group, and 20 participants without sarcopenia will be set as the non-sarcopenia control group. The primary outcome is the scores of Short Physical Performance Battery. The secondary outcomes are body composition, handgrip strength, walking speed, global cognitive function, and incidence of falls. These outcomes will be assessed at baseline, the 12th week and the 24th week. While stool samples from participants will be collected at baseline and the 24th week for analyzing the abundance of gut microbiome. Data will be analyzed in an intention-to-treat protocol.DiscussionThe results of this study will determine whether Baduanjin exercise can be an alternative non-pharmacological approach for older adults with sarcopenia. If they can show positive significance, it will promote Baduanjin exercise in clinical practice among these patients and inform further research involving exercise interventions on the optimal types, timing, and intensity to ameliorate sarcopenia for elderly people.Trial registrationChinese Clinical Trial Registry; Registration number: ChiCTR2100051871; Prospectively registered on October 8th, 2021.

Hand-Eye Coordination and its Relationship with Anthropometric characteristics of Professional Football Players based on their Playing Position

Football is the most popular sport characterized by high and low intensity movements with repeated physical contact. Anthropometric characteristics, coordination motor skills, and functional movement abilities are part of important determinants of success in a football game. This study investigated the relationship between hand-eye coordination and anthropometric characteristics of professional football players based on their playing position. A correlational research design was utilised for this study. The population for this study comprised of 29 professional football players who are members of a professional football club in Nigeria. The participants comprised of 12 forwards, 6 midfielders, 4 goalkeepers and 7 defenders. The weight, height, waist circumference, and hip circumference measurements were obtained using standardised procedures. The body mass index and waist to hip ratio scores of the participants were calculated. The alternate hand wall toss test was used to determine the hand-eye coordination of the participants. Pearson’s product moment correlation and linear regression were used to analyse the results. The level of significance was set at p &lt; 0.05. A significant negative strong correlation was observed between waist to hip ratio and coordination among midfielders (r = -0.841, p = 0.036). There was no significant correlation between waist to hip ratio and coordination among forwards, defenders, and goalkeepers. In addition, there was no significant correlation between body mass index and coordination as well as waist circumference and coordination among football players in all the playing positions. Waist to hip ratio is an important anthropometric measure that can affect the coordination of midfielders in a football team. This should be considered by the coaches and football regulatory bodies before players are assigned to playing positions in the game of football. Position-specific training programmes should be encouraged to enhance football players' performance.

How active can preschoolers be at home? Parents' and grandparents' perceptions of children's day-to-day activity, with implications for physical activity policy

BackgroundThe importance of physical activity in early childhood for establishing long-term health is well understood, yet with the exception of recent WHO guidelines, public health initiatives rarely focus on children below school age. Moreover, little is known about how domestic spaces and day-to-day caring activities influence preschool-age children's physical activity. To examine this, we explore caregivers' perceptions of young children's activities within and outside the home, and we consider how lived experiences of caregiving align (or not) with current physical activity policy. MethodsSemi-structured interviews with 49 parents and grandparents from 16 families were conducted in Oregon, USA; each family had a child aged 3–5 years. Questions focused on caregivers' perceptions of and involvement with children's body weights, activities, and food practices. The interviews were analysed using thematic analysis. Our analysis drew on a materialities framework, attending to relationships between children, caregivers, spaces in and around the home, and everyday activities. ResultsFour themes were developed: appropriateness of outside versus inside spaces for physical activity; making accommodations for physical activity in the home; active spaces of care, referring to relationships among space, activity type, and caregiver attention; and mundane movement, or the low-intensity movement of everyday life. Together, the results highlight that children's day-to-day activities cut across a spectrum of movement, mediated by available spaces and caregiving affordances. ConclusionsAttending to the full spectrum of children's movements highlights how children's activities interlink with family routines, available indoor and outdoor spaces, and the intended uses of these spaces. These interplays between space, care, and physical activity enacted at the household level should inform an integrated, systems-level public health approach to increasing health and well-being for preschool-age children. Suggestions for improvement include coordinating policy development across multiple fields (e.g., housing design, urban planning) that structure the activities of children and their caregivers across ‘home’ and ‘outside’ spaces.

Micro-expression recognition based on facial action learning with muscle movement constraints

As a spontaneous facial expression, micro-expression reveals the psychological responses of human beings. However, micro-expression recognition (MER) is highly susceptible to noise interference due to the short existing time and low-intensity of facial actions. Research on facial action coding systems explores the correlation between emotional states and facial actions, which provides more discriminative features. Therefore, based on the exploration of correlation information, the goal of our work is to propose a spatiotemporal network that is robust to low-intensity muscle movements for the MER task. Firstly, a multi-scale weighted module is proposed to encode the spatial global context, which is obtained by merging features of different resolutions preserved from the backbone network. Secondly, we propose a multi-task-based facial action learning module using the constraints of the correlation between muscle movement and micro-expressions to encode local action features. Besides, a clustering constraint term is introduced to restrict the feature distribution of similar actions to improve categories’ separability in feature space. Finally, the global context and local action features are stacked as high-quality spatial descriptions to predict micro-expressions by passing through the Convolutional Long Short-Term Memory (ConvLSTM) network. The proposed method is proved to outperform other mainstream methods through comparative experiments on the SMIC, CASME-I, and CASME-II datasets.

Free-Living Motor Activity Monitoring in Ataxia-Telangiectasia.

With disease-modifying approaches under evaluation in ataxia-telangiectasia and other ataxias, there is a need for objective and reliable biomarkers of free-living motor function. In this study, we test the hypothesis that metrics derived from a single wrist sensor worn at home provide accurate, reliable, and interpretable information about neurological disease severity in children with A-T.A total of 15 children with A-T and 15 age- and sex-matched controls wore a sensor with a triaxial accelerometer on their dominant wrist for 1 week at home. Activity intensity measures, derived from the sensor data, were compared with in-person neurological evaluation on the Brief Ataxia Rating Scale (BARS) and performance on a validated computer mouse task.Children with A-T were inactive the same proportion of each day as controls but produced more low intensity movements (p < 0.01; Cohen’s d = 1.48) and fewer high intensity movements (p < 0.001; Cohen’s d = 1.71). The range of activity intensities was markedly reduced in A-T compared to controls (p < 0.0001; Cohen’s d = 2.72). The activity metrics correlated strongly with arm, gait, and total clinical severity (r: 0.71–0.87; p < 0.0001), correlated with specific computer task motor features (r: 0.67–0.92; p < 0.01), demonstrated high reliability (r: 0.86–0.93; p < 0.00001), and were not significantly influenced by age in the healthy control group.Motor activity metrics from a single, inexpensive wrist sensor during free-living behavior provide accurate and reliable information about diagnosis, neurological disease severity, and motor performance. These low-burden measurements are applicable independent of ambulatory status and are potential digital behavioral biomarkers in A-T.

Once-Weekly Whole-Body Electromyostimulation Increases Strength, Stability and Body Composition in Amateur Golfers. A Randomized Controlled Study.

Whole-body electromyostimulation (WB-EMS), an innovative training technology, is considered as a joint-friendly, highly customizable and particularly time-effective option for improving muscle strength and stability, body composition and pain relief. The aim of the present study was to determine the effect of 16 weeks of once-weekly WB-EMS on maximum isometric trunk (MITS), leg extensor strength (MILES), lean body mass (LBM) and body-fat content. A cohort of 54 male amateur golfers, 18 to 70 years old and largely representative for healthy adults, were randomly assigned to a WB-EMS (n = 27) or a control group (CG: n = 27). Bipolar low-frequency WB-EMS combined with low-intensity movements was conducted once per week for 20 min at the participants’ locations, while the CG maintained their habitual activity. The intention to treat analysis with multiple imputation was applied. After 16 weeks of once-weekly WB-EMS application with an attendance rate close to 100%, we observed significant WB-EMS effects on MITS (p < 0.001), MILES (p = 0.001), LBM (p = 0.034), but not body-fat content (p = 0.080) and low-back pain (LBP: p ≥ 0.078). In summary, the commercial setting of once-weekly WB-EMS application is effective to enhance stability, maximum strength, body composition and, to a lower extent, LBP in amateur golfers widely representative for a healthy male cohort.

The Relationships between Internal and External Load Measures for Division I College Football Practice.

The aim of this study is to explore the relationships between internal and external load measures in American football. Thirty football players wore a portable integrated monitor unit for 10 weeks during the fall football season. Relationships between internal and external load measurements were determined. Internal load consisted of heart rate zones and heart rate-derived measures and session Ratings of Perceived Exertion (sRPE). External load consisted of distance in different speed zones, total distance traveled, and accelerations. There were many significant positive relationships, but the meaningful relationships (r > 0.5) were between heart rate-derived measures of load (Training Impulse and heart rate reserve) and low-intensity movement and total distance. Only accelerations between 1 and 1.99 m·s−2 were moderately correlated to heart rate-derived internal load. RPE values alone did not correlate strong enough with any of the measure but sRPE training load (sRPE-TL) correlated to most external values. Overall, moderate correlations were present between heart rate-derived internal load to total distance and lower intensity movement. sRPE-TL values had high correlations but were highly dependent on duration, not perceived exertion. When addressing load in American football, duration of the session is a key component in determining internal load as HR data and sRPE alone do not correlate highly with external loads.

Tree ring evidence of slope movements preceding catastrophic landslides

Catastrophic landslides represent one of the most dangerous natural hazards. Detailed knowledge about the pre-landslide behaviour of the affected slope is crucial for effective modelling of the landslide origin in the future or even for creating an early warning system. As precise retrospective reconstruction of slope movements in the pre-landslide period is very limited, dendrogeomorphic methods can be effective tools for these purposes due to the high sensitivity of trees to slope movements and the spatial aspects of data provided by the position of affected trees. This study presents the results of tree ring-based analysis of slope movements preceding three selected catastrophic landslides of different types in the Outer Western Carpathians (Girova 2010—translational rockslide; Brodska 1997—earthflow; Hluboce 2006—rotational rockslide). Three aspects of pre-landslide slope movements were analysed in detail (frequency, intensity, spatial distribution). In total, 300 tree ring series from 150 trees disturbed by pre-landslide movements were used for these purposes. The Girova landslide was preceded by an increasing frequency and intensity of movements but without any spatial pattern. The Brodska landslide was preceded by a low frequency of low-intensity movements without any temporal trends but with significant clustering several years before the landslide. The Hluboce landslide was preceded by a decreasing frequency of movements with increasing intensity and concentration in the source zone. The character of pre-landslide movements is probably influenced by the presence of old landslide structures on the affected slope and by the mechanism of the movements themselves.

24-hour accelerometry in COPD: Exploring physical activity, sedentary behavior, sleep and clinical characteristics.

BackgroundThe constructs and interdependency of physical behaviors are not well described and the complexity of physical activity (PA) data analysis remains unexplored in COPD. This study examined the interrelationships of 24-hour physical behaviors and investigated their associations with participant characteristics for individuals with mild–moderate airflow obstruction and healthy control subjects.Patients and methodsVigorous PA (VPA), moderate-to-vigorous PA (MVPA), light PA (LPA), stationary time (ST), average movement intensity (vector magnitude counts per minute), and sleep duration for 109 individuals with COPD and 135 healthy controls were obtained by wrist-worn accelerometry. Principal components analysis (PCA) examined interrelationships of physical behaviors to identify distinct behavioral constructs. Using the PCA component loadings, linear regressions examined associations with participant (+, positive correlation; -, negative correlation), and were compared between COPD and healthy control groups.ResultsFor both groups PCA revealed ST, LPA, and average movement intensity as distinct behavioral constructs to MVPA and VPA, labeled “low-intensity movement” and “high-intensity movement,” respectively. Sleep was also found to be its own distinct behavioral construct. Results from linear regressions supported the identification of distinct behavioral constructs from PCA. In COPD, low-intensity movement was associated with limitations with mobility (−), daily activities (−), health status (+), and body mass index (BMI) (−) independent of high-intensity movement and sleep. High-intensity movement was associated with age (−) and self-care limitations (−) independent of low-intensity movement and sleep. Sleep was associated with gender (0= female, 1= male; [−]), lung function (−), and percentage body fat (+) independent of low-intensity and high-intensity movement.ConclusionDistinct behavioral constructs comprising the 24-hour day were identified as “low-intensity movement,” “high-intensity movement,” and “sleep” with each construct independently associated with different participant characteristics. Future research should determine whether modifying these behaviors improves health outcomes in COPD.

Effect of fatigue on the movement activities of senior male Zimbabwean national rugby sevens players

The objective of the study was to determine the effect of fatigue on the percentage of time sevens rugby players spend on the movement activities during the two different halves of match play and to compare the percentage of time starter and substitute players spend on high and low-intensity movement activities. Sixty-one time-motion analyses data-sets of twelve (12) senior male elite Zimbabwean rugby sevens players with a mean age of 27.8 years were gathered at two International Sevens rugby tournaments. Time-motion analysis data were captured at 10 Hz with a minimaxX GPS device. Results indicated that starter players covered a significantly greater distance (r = 0.26) than substitute players. However, substitute players covered a significantly greater relative distance (distance per minute) (r = 0.33) than the starter players. Hence, the substitute players had less rest during match play and therefore a higher work-to-rest ratio than the starter players. No large practically significant differences found between the high intensity movement activities of the players during the two halves of match play, suggesting that fatigue did not affect the players’ movement activities. The results therefore suggest that the use of substitute players may support the ability of teams to increase the players work rate.

Fast and behavior-selective exploitation of a marine fish targeted by anglers.

Harvesting of wild-living animals is often intensive and may selectively target heritable behavioral traits. We studied the exploitation dynamics and the vulnerability consequences of individual heterogeneity in movement-related behaviors in free-ranging pearly razorfish (Xyrichthys novacula). Using underwater-video recording, we firstly document a fast and high exploitation rate of about 60% of the adult population removed in just few days after the opening of the season. Subsequently, we tagged a sample of individuals with acoustic transmitters and studied whether behavioral traits were significant predictors of the vulnerability to angling. Tagged individuals revealed repeatable behaviors in several home range-related traits, suggesting the presence of spatial behavioral types. The individuals surviving the experimental fishery showed only localized and low-intensity movement patterns. Our study provides new insights for understanding the harvesting pressures and selective properties acting on behavioral traits of recreational fishing. Many fish stocks around the globe are today predominantly exploited by recreational fisheries. The fisheries-induced change in fish behavior described here may be therefore widespread, and has the potential to alter food-webs, profitability of the fisheries and to affect stock assessment by eroding catchability in the long-term.

Fluctuations in Activity Demands Across Game Quarters in Professional and Semiprofessional Male Basketball.

Examination of activity demands and stoppage durations across game periods provides useful insight concerning fatigue, tactical strategies, and playing pace in team sports such as basketball. Therefore, the aims of this study were to quantify and compare game activity fluctuations across quarters in professional and semiprofessional basketball players. Video-based time-motion analyses were conducted across multiple games. Frequencies, total durations (in seconds), total distances (in meters), and mean velocities (in meters per second) were calculated for low-intensity movement (≤3 m·s), high-intensity movement (>3 m·s), shuffling, and dribbling activity. Frequencies were determined for jumping and upper-body activity; stoppage durations were also calculated. Separate repeated-measures analysis of variance and Cohen's d were used to identify significant differences and quantify the effect sizes between game quarters for all outcome measures, respectively. Pearson correlation analyses were performed to determine the relationship between stoppage duration and all activity measures. The results showed significantly (p ≤ 0.05) reduced dribbling (3.09 ± 0.03 m·s vs. 2.81 ± 0.01 m·s) and total (2.22 ± 0.04 m·s vs. 2.09 ± 0.03 m·s) activity velocities during the third compared with the first quarter in professional players. Furthermore, effect size analyses showed greater decreases in high-intensity (professional: d = 1.7-5.4; semiprofessional: d = 0.3-1.7), shuffling (professional: d = 2.3-3.2; semiprofessional: d = 1.4-2.1), and total (professional: d = 1.0-4.9; semiprofessional: d = 0.3-0.8) activity and increases in dribbling (professional: d = 1.4-4.7; semiprofessional: d = 2.5-2.8) with game progression in professional players. In semiprofessional players, stoppage duration was significantly (p ≤ 0.05) related to various low-intensity (R = 0.64-0.72), high-intensity (R = 0.65-0.72), and total (R = 0.63-0.73) activity measures. Although not directly measured, the observed game activity fluctuations were likely because of a combination of physiological (e.g., muscle glycogen depletion, dehydration), tactical (e.g., ball control, game pace), and game-related (e.g., time-outs, player fouls) factors. Basketball coaches can use the provided data to (a) develop more precise training plans and management strategies, (b) elevate semiprofessional player performance closer to the professional level, and (c) incorporate tactical strategies to maximize the benefits of stoppages.

Circadian behaviour of Tectus (Trochus) niloticus in the southwest Pacific inferred from accelerometry.

BackgroundBehaviour and time spent active and inactive are key factors in animal ecology, with important consequences for bioenergetics. For the first time, here, we equipped the gastropod Tectus (= Trochus) niloticus with accelerometers to describe activity rhythms at two sites in the Southwest Pacific with different temperature regimes: New Caledonia and Vanuatu.ResultsBased on a 24-hour cycle, T. niloticus activity began at dusk and gradually stopped during the night, before sunrise. This nocturnal behaviour was characterised by short (duration <30 s), low intensity (acceleration < 0.12 ɡ) movements and was probably associated with foraging behaviour. We assumed that activity ceased once the animal was satiated. Our analysis of two size groups in Vanuatu (80–90 mm vs. 120–140 mm, basal shell diameter) revealed a size effect; smaller specimens displayed greater activity, reflected by more intense and longer movements while migrating at night toward the edge of the reef. This nocturnal behaviour is not uncommon for grazing gastropods and is mainly associated with attempting to avoid visual predators whilst feeding.ConclusionsThe use of accelerometers coupled with light and temperature sensors provided detailed information on topshell behaviour and physiology under natural conditions. These data provide a foundation for identifying potential changes in the fine-scale behaviour of T. niloticus in response to environmental changes, which is essential in animal ecology and stock conservation.