Textbooks tell us that the coupling constant of Dirac magnetic monopoles is 34.259. Here I show by using the quark hypothesis that at zero temperature the coupling constant is as high as 308.331. Moreover I show that it is a running coupling constant and is smaller than 0.5 at the Planck temperature.

The purpose of this research has been to analyze the organizational structures of the different federations and entities representing the modalities of trail-running, skyrunning and mountain running and how they have settled in the current sports landscape. The main task of these entities is to act as hosts of the legally established modalities, both internationally and nationally, applying their respective regulations and statutes unilaterally. Through an in-depth review of the different regulations, statutes and current articles of all the organizations that represent the different disciplines, we can observe how a sport modality that seems to be the same is nevertheless distant in its execution (regulations, championships, classifications, systems of points, ...) and that has led to the international level being established in different sport modalities (trail-running and skyrunning) and at the level of the Spanish territory, it has led to an administrative dispute to know who has the powers to approve the sports competitions.

The marathon sport events and those who participate in these have grown over the last years reflecting notably an augmentation of women and master runners participation. The aim of the present narrative review was to briefly present the results of studies on anthropometric, physiological and training characteristics, as well as predictors of performance, in marathon runners. It was observed that performance was better in runners with small body weight, body mass index, body fat percentage, and rate of endomorphy. With regards to physiology, an increased maximal oxygen uptake, anaerobic threshold, and improved running economy could result in faster race time. The training variables that could predict performance involved weekly training volume (distance) and intensity (running speed), as well as history of training (years). A combination of these three broad categories of characteristics may offer an approximate estimation of the race speed considering that other aspects (e.g., nutrition, biomechanic and motivation) influence race performance, too. In summary, the findings of the present study provided an overview of anthropometric, physiological and training characteristics associated with marathon race time; thus, an optimization of any of these characteristics would be expected to improve race time.

Running is a basic form of human locomotion and one of the most popular sports worldwide. While the leg biomechanics of running have been studied extensively, few studies have focused on the upper-body movement. However, an effective arm swing and longitudinal rotation of the shoulders play an important role in running efficiency as they must compensate for the longitudinal torques generated by the legs. The aim of this study is to assess the upper-body rotation using wearable inertial sensors and to elucidate its relation to energy expenditure. Eighty-six junior elite middle and long-distance runners (37 female, 49 male) performed an incremental treadmill test with sensors attached on both shoulders, tibiae and the sacrum. Mean and total horizontal shoulder and pelvis rotation per stride were derived while energy costs were determined using respiratory gas analysis and blood sampling. Results show that shoulder and pelvis rotation increase with running speed. While shoulder rotation is more pronounced in female than in male runners, there is no sex difference for pelvis rotation. Energy cost of running and upper trunk rotation prove to be slightly negatively correlated. In conclusion, upper body rotation appears to be an individual characteristic influenced by a sex-specific body mass distribution.

Objectives The aim of this study was to measure the magnitude of forces in the joints of the lower limb whilst running barefoot and compare them to the forces generated whilst wearing running shoes with a thick midsole.MethodsTwenty-three volunteers who utilised running as their main sport or a training aid ran as training aid were included in this study. Each volunteer would run down a fourteen-meter-long corridor both barefoot and with running shoes. Forces for joints of the lower limb were collected using a Vicon motion analysis system and force plates. The joint forces for the ankles, knees and hips were taken as the largest joint force experienced during the stance phase and then averaged over five running trials.ResultsThere was significant reduction in the joint forces for the ankles, knees, and hips when barefoot running compared to the shod condition.ConclusionBarefoot running could be utilised to prevent both acute and degenerative injuries of the lower limb.

This study investigated the impact of six high-intensity interval training (HIIT) running sessions at 1% or 10% slope on various physiological and performance parameters in 25 men. The partic-ipants underwent assessments of VO2max, time to exhaustion at 1% slope (TLim1%), and time to exhaustion at 10% slope (TLim10%) in the initial three visits. They were then randomly assigned to control (CON), HIIT at 1% slope (GT1%), or HIIT at 10% slope (GT10%) groups. Over three weeks, participants performed six HIIT sessions with equalized workload based on their indi-vidual maximal oxygen uptake (vVO2max). The sessions comprised 50% of TLim, with a 1:1 ratio of exercise to recovery at 50% vVO2max. Results indicated significant improvements in VO2max and peak velocity (VPeak) after HIIT at both slopes. Heart rate (HR) behavior differed between sessions for GT1%, while no significant differences were observed for GT10%. Rating of perceived exertion (RPE) significantly reduced for GT1% after the third session, with a similar trend for GT10%. In summary, six sessions of 1% or 10% slope HIIT effectively enhanced VO2max and VPeak, but there was no improvement in TLim performance, suggesting no adaptive transfer between training groups.

The influence of playing formations and team ranking on the physical performance of professional soccer players is an open question that needs to be explored. The present study aimed to investigate the impact of these factors on the physical exertion of Serie A soccer players. We analyzed match data from 375 players, categorizing teams based on their final ranking and comparing performance across different playing formations. Krustal-Wallies test, and Dunn test with Bonferroni adjustment, revealed that high-ranking (HR) teams exhibited a higher percentage of high-intensity (HI) accelerations compared to mid-ranking teams, suggesting the critical role of HI efforts in achieving favorable match outcomes. Moreover, the 4-3-3 playing formation was associated with greater acceleration demands than other formations, particularly in HR teams. Our study also established benchmarks for various performance metrics, enabling coaches to assess player performance and identify potential signs of overtraining. These findings contribute to a deeper understanding of the physical demands in soccer and offer practical implications for coaches and players in optimizing training and performance strategies.

The central nervous system (CNS) controls movements and regulates joint stiffness with muscle coactivation, but until now few studies have examined muscle pairs during running. This study aims to investigate differences in lower limb muscle coactivation during gait at different speeds from walking to running. Nineteen healthy runners walked and ran at speeds ranging from 0.8 km/h to 9.3 km/h. Twelve lower limb muscles' coactivation was calculated using the time-varying multi-muscle coactivation function (TMCf) with global, flexor-extension, and rostro-caudal approaches. Spatiotemporal and kinematic parameters were also measured. We found that TMCf, spatiotemporal and kinematic parameters were significantly affected by gait speed for all approaches. Significant differences were observed in the main parameters of each coactivation approach, and in the spatiotemporal, and kinematic parameters at the transition between walking and running. Positive and negative strong correlations were found between global coactivation parameters and center of mass displacements, as well as some spatiotemporal parameters, regardless of gait speed. Our findings suggest that walking and running have different coactivation patterns and kinematic characteristics, with the whole-limb stiffness exerted more synchronously and stably in running. The coactivation indexes and kinematic parameters could be the result of global coactivation, which is a sensory-control integration process used by the CNS to deal with more demanding and potentially unstable tasks like running.

Instep weights cause mechanical changes, modifying muscle activity and changing ground plantar support. 30 semi-professional sprinters, randomized in 3 groups [no-weight, Ascending (50, 100, 150 and 200g), Descending (200, 150, 100 and 50g)] run 6 consecutive 50-meter series at maximum speed (first and sixth without weights); partial, total times and speed were analyzed. Instep weights were safe and well tolerated. 6th series speed decreased except in men’s ascending group, who achieved a lower time in sixth compared to first series. Weights presented in ascending order in men during warm-up could improve running time. Instep weights neuromuscular effects could compensate men’s tiredness in last series; weights could be included in training methodologies. Men training weights presented in ascending order may provide better results.

By applying a running average (with a window-size= d), we could transform Discrete data to broad-range, Continuous values. When we have more than 2 columns and one of them is containing data about the tags of classification (Class Column), we could compare and sort the features (Non-class Columns) based on the R2 coefficient of the regression for running averages. The parameters tuning could help us to select the best features (the non-class columns which have the best correlation with the Class Column). “Window size” and “Ordering” could be tuned to achieve the goal. this optimization problem is hard and we need an Algorithm (or Heuristics) for simplifying this tuning. We demonstrate a novel heuristics, Called Simulated Distillation (SimulaD), which could help us to gain a somehow good results with this optimization problem.

The effectiveness of combining strength-specific training with endurance training to enhance the performance of endurance runners remains uncertain. This study aimed to analyze effect of practising maximum-strength (MAX), explosive strength (EXP) or both combined (COMB) on seven runners’ performance-indicators: vertical jump (VJ), one-repetition-maximum-squat (1RM), peak-velocity/peak-running-speed (PV), lactate-threshold (over incremental-test-protocols, LT), middle-distance-time-trial (TT), maximum-oxygen-consumption (VO2max), running-economy (RE). Systematic-review (Scopus, Wed of Science, Sports Discuss, PubMed) with meta-analysis was conducted following PRISMA standards. Inclusion-criteria (PICOS) were: recreational or well-trained athletes aged 18-45 performing concurrent-training ≥five-week. Used search-terms were related to different types of strength/endurance, participants’ age, sport-modality. 20 manuscripts were selected, quality-assessed with PEDro. MAX training is more effective than EXP, COMB in improving VJ, 1RM, PV, while COMB is more effective than MAX, EXP to enhance TT. MAX is more effective than EXP in improving LT. Concurrent-workouts do not provide additional benefits to VO2max. It is unknown which strength-modality (MAX, EXP or COMB) is more effective in improving RE. Concurrent-training is more effective than single-mode-endurance-training for enhancing specific performance-variables in adult-endurance-runners. Middle-, long-distance-runners may consider incorporating MAX-training to target specific goals, e.g., improving VJ, 1RM, LT, PV while utilizing COMB-training to enhance TT. Certain variables may benefit from EXP. New randomized-controlled-trials are required to confirm these findings.

Physical activity is considered a promising preventive intervention to reduce the risk of developing Alzheimer’s disease (AD). However, the positive effect of exercise therapy has not been proven conclusively yet, likely due to confounding factors such as varying activity regimens and life or disease stages. To examine the impact of different routines of physical exercise in the early disease stages, we subjected young 5xFAD and wild-type mice to 1-day (acute) and 30-day (chronic) voluntary wheel running and compared them with age-matched sedentary controls. We observed a significant increase in brain lactate levels in acutely trained 5xFAD mice relative to all other experimental groups. Subsequent brain RNA-seq analysis did not reveal major differences in transcriptomic regulation between training durations in 5xFAD mice. In contrast, acute training yielded substantial gene expression changes in wild-type animals relative to their chronically trained and sedentary counterparts. The comparison of 5xFAD and wild-type mice showed the highest transcriptional differences in the chronic and sedentary groups, whereas acute training was associated with much fewer differentially expressed genes. In conclusion, our results suggest that different training durations did not affect the global transcriptome of 3-month-old 5xFAD mice, whereas acute running seemed to induce a similar transcriptional stress state in wild-type animals as already known for 5xFAD mice.

Smartwatches are one of the most relevant fitness trends of the past two decades, and they collect increasing amounts of health and movement data. The accuracy of these data may be questionable and requires further investigation. Therefore, the aim of the present study is to validate smartwatches for use in triathlon training. Ten different smartwatches were tested for accuracy in measuring heart rate, distance (via global navigation satellite systems, GNSS), swim stroke rates and the number of swim laps in a 50 m Olympic-size pool. The optical heart rate measurement function of each smartwatch was compared to that of a chest strap. Thirty participants (15 females, 15 males) ran five 3-minute intervals on a motorised treadmill to evaluate the accuracy of the heart rate measurements. Moreover, for each smartwatch, running und cycling distance tracking was tested over six runs of 4,000 m on a 400 m tartan stadium track, six hilly outdoor runs over 3.4 km, and four repetitions of a 36.8 km road bike course, respectively. Three swimming protocols ranging from 200 m to 400 m were performed in triplicate in a 50 m Olympic-size pool, evaluating tracked distance and detected number of strokes. The mean absolute percentage errors (MAPEs) for the average heart rate measurements varied between 3.1% and 8.3%, with the coefficient of determination ranging from 0.22 to 0.79. MAPE results ranged from 0.8% to 12.1% for the 4,000 m run on the 400 m track, from 0.2% to 7.5% for the 3.4 km outdoor run, and from 0.0% to 4.2% for the 36.8 km bike ride. For the swimming tests, in contrast, the deviations from the true distance varied greatly, starting at a 0.0% MAPE for the 400 m freestyle and reaching 91.7% for the 200 m medley with style changes every 25 m. In summary, for some of the smartwatches, the measurement results deviated substantially from the true values. Measurements taken while road cycling over longer distances with only a few curves were in relative terms more accurate than for outdoor runs and even more accurate than for the 400 m track. In the swimming exercises, the accuracy of the measured distances was severely deteriorated by the medley changes among the majority of the smartwatches. Altogether, the results of this study should help in assessing the accuracy and thus suitability of smartwatches for general triathlon training.

Purpose：Herein, aimed to explore routines to improve students' physical health.Methods:We explored the integration of extracurricular fitness running "Lerun" into college physical education curriculum. Firstly, experimental and the referring groups were selected by experimental method, in which only the experimental group was intervened in combination with extracurricular fitness running "Lerun". After two experiments, the experimental and referring groups were compared in terms of physical fitness (speed, strength, endurance, flexibility, explosive force, etc.), sports skills, body shape, cardiopulmonary function, etc. Results:After T-test, significant differences (p<0.05) between these two groups prove that the students' physical health status of experimental group is better than that of the referring group. Conclusion：It manifests that integrating extracurricular fitness running "Lerun" into college physical education curriculum is an effective means to improve students' physical health.

(1) Background: Foot strike pattern and cadence are two important variables that are related to sport performance and injury risks; the objective of this study is to analyse the foot strike pattern and cadence of the male elite athlete that participated in the Tokyo Olympic Games marathon. (2) Methods: Two independent researchers analysed the foot strike pattern of the first 51 participants in the 5km, and the cadence of the finalists in three different segments of the race. Descriptive statistics were presented for the main variables of this study. A repeated measures ANOVA was used to study the differences in cadence between different sections of the race (p&lt;0.05). (3) Results: Average of the cadence of the eight finalists was 185.5 steps per minute (SD ± 5.1). No differences between sections of the race were found. The more most common foot strike pattern was midfoot strike pattern, followed by rearfoot strike pattern, and forefoot strike pattern. The results of cadence are in line with previous studies that analysed elite athletes, with the values being higher than other research involving recreational runners. (4) Conclusions: elite marathon runners mostly run with a running non-rearfoot strike pattern and a cadence of over 185 steps per minute.

The overarching purpose of this review was to highlight the utility of different aerobic field tests in terms of the parameters they provide, with a specific focus on shuttle running and all-out testing. Various field tests are discussed in detail and are categorised according to linear continuous running tests (e.g. 12-minute Cooper Test, University of Montreal Track Test [UMTT], 1200/1600 m time trials, 3-minute all-out test for running [3MT]), intermittent shuttle running tests (e.g. yo-yo inter-mittent recovery test level 1 [YYIR1], 30-15 intermittent fitness test [IFT], and the intermittent all-out shuttle test [IAOST]), and continuous shuttle running tests (e.g. 1.2 km shuttle run test [1.2SRT], maximal multi-stage 20-m shuttle test [MSR], 25-m, 30 m and 50-m 3-minute all-out shuttle test [AOST]). Readers will be guided through the theoretical and practical underpinnings of the 3MT methodology, where the all-out testing methodology is stationed within the testing paradigm, and how to practically implement and interpret the results thereof.

The need to carry different items, which become an extra load, is a characteristic of trail running. The aim of this study is to determine physiological-metabolic changes produced by running with extra load. Four male well-trained trail runners completed three treadmill maximal metabolic tests carrying different loads (0% (L0), 5% (L5), and 10% (L10) of their body mass) in a weighted vest. Gasses exchange was monitored to assess ventilatory thresholds 1 (VT1), and 2 (VT2), zone of maximal fat oxidation, and peak oxygen consumption (VO2peak). Heart rate (HR), power and velocity (V) were tracked for comparing their behavior. A repeated measures ANOVA showed significant differences in V (p&lt;.001; ηp2= 0.910) as a limitation for reaching peak velocity (Vpeak) with L10 respect to L0 (p=0.001), and L5 (p=0.011). Power expression showed differences (p=0.068; ηp2= 0.592). It tended to be greater with L10 than L0 (p=0.057), despite achieving lower V. VT2 tended to occur at different %VO2peak (p=0.069; ηp2= 0.591). L5 VT2 was reached at higher %VO2peak than L0 (p=0.062), and L10 (p=0.071). ANOVA also showed a tendency to signification for V at this point (p= 0.098; ηp2= 0.538). In conclusion, L10 seems to limit Vpeak while L5 may delay VT2 expression.

Body weight support (BWS) and incline running (IR) are commonly used either during rehabilitation or during training separately, with many positive effects on athletes’ performance and rehabilitation. The aim of this study is to investigate the effect of BWS and IR. In eighteen healthy men (age: 20.3 ± 1.2 yr, body weight: 70.2 ± 4.8 kg, body height: 179.6 ± 5.4 cm), the changes in electromyographic activity (EMGA) during a 10-min run with BWS (15% or 30% of body weight; in different occasions) and IR at 7%, as well as jumping performance and gait spatiotemporal parameters were evaluated. Lower Rating of Perceived Exertion and a significant decrease in VL (33,4%), SOL (17%), and GL EMGA (28.5%, p &lt; 0.05) but not in GM (10.5%, p &gt; 0.05), were observed during BWS30% at 7% slope compared to flat running. Also, low-frequency fatigue of the quadriceps was induced only after running without BWS at 7% slope (P = 0.011). No changes were found in jumping performance (p = 0.246) and gait spatiotemporal parameters (p &gt; 0.05) except for flight time (p &lt; 0.006). In conclusion, compared to normal flat running, BWS reduces electromyographic activity and fatigue during slope running.

(1) Background: This report examines the unique demands of off-road triathlon (XT) by presenting physiological, field, and race data from a national champion off-road triathlete using several years of laboratory and field data to detail training and race intensity. (2) Methods: Laboratory and field data were collected when the athlete was at near peak fitness and included oxygen consumption (VO2), heart rate (HR), power output (W), and blood lactate (BLC) during cycling and running, while HR, cycling W, and running metrics were obtained from training and race data files over a period of seven years. Intensity was described using % HR max zones (Z) 1 &lt; 75%, 2 = 75 - 87%, and Zone 3 &gt; 87%, and W. An ordinary least squares analysis was used to model differences between event types. (3) Results: Weather conditions were not different across events. XT events had twice the elevation change (p&lt;0.01) and two-three times greater W’ (p&lt; 0.001) than road triathlon (ROAD), but similar HR intensity profiles (max, avg, and zones); both events are predominately performed at &gt; Z2 or higher intensity. Championship XT events were longer (p&lt;0.01) , with higher kJ expenditure (p&lt;0.001). OLS modelling suggested three variables were strongly related (R2 = 0.84; p &lt; 0.0001) to cycling performance: event type (XT vs ROAD), total meters climbed, and total bike duration. Championship XT runs were slower than either regional (p&lt;0.05) or ROAD (p&lt;0.01) runs, but HR intensity profiles similar. OLS modelling indicates that slower running is linked to either greater total bike kJ expenditure (R2 = 0.57; p&lt;0.001), or total meters gained (R2 = 0.52; p&lt;0.001). Race simulation data support these findings but failed to produce meaningful differences in running. Conclusions: XT race demands are unique and mirror MTB and trail running demands. XT athletes must be mindful of developing anaerobic fitness, technical ability, and aerobic fitness, all of which contribute to off-road cycling economy. It is unclear whether XT cycling affects subsequent running performance different from ROAD cycling.

Running on a non-motorized, curved-deck treadmill is thought to improve gait mechanics. It is not known, though, if the change in gait carries over to running on a motorized treadmill or level ground. To determine the effect of running on a curved non-motorized treadmill (CNT) on gait characteristics measured during a subsequent bout of running on a traditional motorized treadmill (TMT). Sixteen healthy college-aged participants, age (mean±SD) 20.4±1.6 years volunteered to have their gait analyzed while running on a TMT and CNT. After familiarization and warm-up on both treadmills, each subject completed five, 4-minute bouts of running alternating between traditional motorized and curved non-motorized treadmills: TMT-1, CNT-1, TMT-2, CNT-2, and TMT-3. Variables of interest included step length (m), stride length (m), imbalance score (%), and step angle (°) and were measured using Optogait gait analysis equipment. Differences in gait char acteristics among TMT-1, TMT-2, and TMT-3 can be attributed to running on the CNT. The results show that running on a CNT resulted in significant changes in gait characteristics. These findings suggest that running on a CNT can significantly alter gait characteristics may result in improvements in running gait that persist to subsequent running on a TMT.

Most existing the freeway hard shoulder running (HSR) strategy literature only focuses on the traffic flow with human-driven vehicles (HDVs) but neglects the possible impacts of connected automated vehicles (CAVs) with various penetration rates on the macroscopic traffic flow. The purpose of this paper is to detect whether the effects of mixed traffic flow for the freeway HSR strategy differ the traditional traffic flow or not. An approach based on microscopic simulation with factorial experimental design is adopted in this study, and novel results are obtained from the discussion and statistical analyses of simulation results. The results showed that the penetration rates of CAVs have a positive influence both on the traffic efficiency and safety on freeway HSR regardless of the prevailing traffic flow conditions. Furthermore, the implementation of the HSR strategy has the potential to markedly enhance traffic efficiency across a range of varying traffic demands. However, different speed limits for the HSR can lead to varying degrees of efficiency improvement under different traffic demands. Finally, we find a complex interplay between traffic flow conditions and the impact of HSR on TTC values and overall traffic safety.

Background: Runners have high incidence of repetitive load injuries, and habitual runners often use smartwatches with embedded IMU sensors to track their performance and training. If accelerometer information from such IMUs can provide information about individual tissue loads, then running watches may be used to prevent injuries. Methods: We investigate a combined physics-based simulation and data-based method. 285 running trials from 76 real runners are subjected to physics-based simulation to recover forces in the Achilles tendon and patella ligament, and the collected data are used to train and test a data-based model using elastic net and gradient boosting methods. Results: Correlations up to 0.95 and 0.71 for the patella ligament and Achilles tendon forces, respectively, are obtained, but no single best predictive algorithm can be identified. Conclusions: Prediction of tissues loads based on body-mounted IMUs appears promising but requires further investigation before deployment as a general option for users of running watches to reduce running-related injuries.

Background: Depending on the phase of the menstrual cycle the athlete is in, some kinetic, physiological and fatigue variables will show differences. The aim of this study is to analyze whether there are changes in these variables over the course of the menstrual cycle. Methods: Eight regular female runners and triathletes performed a maximal treadmill test, as well as a submaximal test (6’ stages at 50%, 60% and 80% of maximal aerobic speed) in each of the phases of the menstrual cycle: bleeding phase (day 2.4 ± 0.7), follicular phase (day 10.4 ± 2.2) and luteal phase (day 21.8 ± 2.1). Running dynamics were measured (using RunScribe) at the end of each test, as were lactate concentration, heart rate and fatigue (evaluated on a scale of 0 to 5). Results: Higher shock (G) values were recorded in the bleeding phase and higher vertical spring stiffness (kN/m) in the follicular phase. The phase of the menstrual cycle had a significant effect on average and peak heart rate, which was significantly higher in the follicular phase. Conclusions: Higher vertical spring stiffness was observed in the follicular phase, as well as higher peak and average heart rate.

The rapid penetration of social media has been redefining every facet of the old marketing and customer engagement tactics, not only for the low-end and mass products but also for luxury brands. In this context, brands are dealing with the challenge of keeping the balance between using mass marketing strategies concurrent with accentuating the exclusivity of their offerings. Social media can be considered a boon if brands employ them to reach the right audience and use the right platform by incorporating the right content. In this work, we propose a sector-specific, integrated, and holistic investigation of the social media strategies of luxury brands, together with the impact they generate in terms of the engagement level of the users as an indicator of their success. We provide empirical validation of the method in the sector of luxury fashion brands in the Italian market, providing qualitative and quantitative analysis of the content shared on social media, considering the type, timing, and modality of the sharing. We evaluate consumer-brand engagement in different contexts, including important live events in the field.

Maximal heart rate (HRmax) is a widely used measure of cardiorespiratory fitness. Prediction of HRmax is an alternative to cardiopulmonary exercise testing (CPET), but its accuracy among endurance athletes (EA) requires evaluation. This study aimed to externally validate HRmax prediction models in the EA independently for running and cycling CPET. 4043 runners (age=33.58 (8.12) years; 83.53% males; BMI=23.66 (2.54) kg·m−2) and 1026 cyclists (age=36.88 (9.03) years; 89.67% males; BMI=24.04 (2.65) kg·m−2) underwent maximum CPET. Student t-test, mean absolute percentage error (MAPE), mean absolute error (MAE), and root mean square error (RMSE) were applied to externally validate 8 running and 5 cycling HRmax equations. HRmax was 184.60 (9.79) beats·min−1 and 182.66 (10.28) beats·min−1 respectively for running and cycling, p=0.001. Measured and predicted HRmax differed significantly (p=0.001) for 9 of 13 (69.23%) models. HRmax was overestimated by 8 (61.54%) and underestimated by 5 (38.46%) formulae. Overestimated HRmax ranged 0.08-4.94 beats·min−1 and underestimated HRmax ranged 0.03-4.90 beats·min−1. MAE and RMSE were 0.18-4.94 beats·min−1 and 9.13-10.47, respectively. MAPE ranged 3.95-4.69%. Prediction models do not allow for accurate estimation of HRmax. HRmax was more often underestimated than overestimated. Predicted HRmax can be implemented for EA as a supplemental method but CPET is the preferable approach.

This study profiled morphological and laboratory-derived performance biomechanics by position of American style football players training for the National Football League draft. Fifty-five players were categorized into Big (e.g., lineman; n=17), Big-skill (e.g., tight end; n=11), and Skill (e.g., receiver; n=27) groups. Body fat (BF%), lean body mass (LBM), total body mass, running force and ground contact time (GCT), countermovement jump height (CMJ-JH), CMJ normalized peak power (CMJ-NPP), and reactive strength were measured in a laboratory. Asymmetry was calculated for running force, GCT, and CMJ eccentric and concentric impulse (IMP). MANOVA determined between-group differences, and radar plots for morphological and performance characteristics were created using Z-scores. There was a significant between-group difference, F(26,80)=5.70, p&lt;0.001;Wilk’s Λ=0.123, partial η2=0.649. Fisher’s least squares difference post-hocs showed Skill had greater JH, CMJ-NPP, reactive strength, and running force versus Big but not Big-skill, p&lt;0.05. Big had greater BF%, LBM, total body mass, and GCT than Skill and Big-Skill, p&lt;0.05. Big-skill had greater GCT asymmetry than Skill and Big, p&lt;0.05. Asymmetries in running forces, and CMJ eccentric and concentric IMP were not different, p&gt;0.05. Morphological and performance biomechanics differences are pronounced between Skill and Big. Big-skill possess characteristics from both groups. Laboratory-derived results provide specialized profiles of draft trainees.

A 36-year-old professional marathon runner reported sudden heart palpitations occurring during competitions, with heart rates (HR) of 230 bpm recorded on sports HR monitor (HRM) over 4 years. These episodes subsided upon the cessation of exercise. Electrocardiograms, echocardiography, and cardiac magnetic resonance imaging results were borderline for athlete's heart. Because an electrophysiology study and standard exercise tests provoked no arrhythmia, doctors suspected Munchhausen syndrome. Ultimately, an exercise test that simulated the physical effort during a competition provoked tachyarrhythmia consistent with the HRM readings. This case demonstrates the diagnostic difficulties related to exercise-induced arrhythmia and the diagnostic usefulness of sports HRMs.

This literature review investigates the role of plumage in the hunting tactics of Velociraptor, integrating anatomical analysis and biomechanical modeling. Velociraptor, a swift and agile theropod from the Late Cretaceous, exhibited advanced intelligence and sensory capabilities that contributed to its effective predatory strategies. Recent discoveries have confirmed that Velociraptor was covered in feathers, with quill knobs indicating well-developed plumage. This review explores the potential functions of feathers beyond flight, focusing on their impact on hunting behavior. Evidence suggests that Velociraptor’s plumage likely facilitated camouflage and enhanced aerodynamic control, improving its stealth and maneuverability during high-speed chases. Additionally, feathers might have contributed to stability during incline running, further supporting its adaptability in diverse environments. Velociraptor’s hunting strategies, characterized by agility and precision, were complemented by its feathered anatomy, which may have also played a role in pack hunting and social interactions. Overall, the integration of plumage with Velociraptor’s anatomical features and behavioral adaptations underscores its efficiency as a predator, demonstrating how feathers may have been a critical factor in its successful hunting tactics.