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Background: Understanding the relationship between the functional state of the musculoskeletal system and skating performance in ice hockey players is essential, as it can provide valuable insights for the development of training programs tailored to the specific needs of athletes. This study investigated the relationship between functional movement patterns, dynamic balance, and ice speed and agility in young elite male ice hockey players., Methods: The study involved sixty elite male ice hockey players aged 14 to 18 years, with an average age of 15.9 ± 0.85 years and training experience ranging from 7 to 9 years. Functional movement patterns were evaluated using the Functional Movement Screen ™ (FMS TM ). Dynamic balance was assessed using the lower quarter Y-Balance test (YBT-LQ). Fitness tests on ice were conducted using a professional Smart Speed measurement system., Results: Negative correlations were found between the in-line lunge and the results of the 5-m forward (rho = -0.31, p = 0.018) and 5-m backward (rho = -0.27, p = 0.040), as well as between the hurdle step and the 30-m forward skating test result (rho = -0.26, p = 0.043). Positive correlations were observed between shoulder mobility and both forward (5-m: rho = 0.27, p = 0.035) and backward skating results (5-m: rho = 0.35, p = 0.006; 30-m: rho = 0.26, p = 0.047), and between active straight leg rise and both the 5-m forward skating (rho = 0.38, p = 0.002) and agility tests (rho = 0.39, p = 0.002). The study also revealed positive correlations between the magnitude of asymmetries in the anterior reach distance of the right and left legs and the results of 5-m forward (rho = 0.34, p = 0.009) and backward skating (rho = 0.32, p = 0.013). Additionally, a positive correlation was found between the agility test and the magnitude of asymmetries in the posteromedial reach distance (r = 0.32, p = 0.012) as well as the composite YBT score (r = 0.28, p = 0.031). Negative correlations were found between normalized reach distances in the YBT-LQ and performance outcomes in both forward and backward skating, as well as in the agility test, indicating that greater reach distance corresponds to faster skating., Conclusions: These findings suggest the potential impact of balance and hip mobility on skating speed and agility and emphasize the importance of symmetry for optimal performance among ice hockey players., Competing Interests: The authors declare that they have no competing interests., (© 2024 Grabara and Bieniec.)

The aim of this current work is to identify three different gears of cross-country skiing utilizing embedded inertial measurement units and a suitable deep learning model. The cross-country style studied was the skating style during the uphill, which involved three different gears: symmetric gear pushing with poles on both sides (G3) and two asymmetric gears pushing with poles on the right side (G2R) or to the left side (G2L). To monitor the technique, inertial measurement units (IMUs) were affixed to the skis, recording acceleration and Euler angle data during the uphill tests performed by two experienced skiers using the gears under study. The initiation and termination points of the tests were controlled via Bluetooth by a smartphone using a custom application developed with Android Studio. Data were collected on the smartphone and stored on the SD memory cards included in each IMU. Convolutional neural networks combined with long short-term memory were utilized to classify and extract spatio-temporal features. The performance of the model in cross-user evaluations demonstrated an overall accuracy of 90%, and it achieved an accuracy of 98% in the cross-scene evaluations for individual users. These results indicate a promising performance of the developed system in distinguishing between different ski gears within skating styles, providing a valuable tool to enhance ski training and analysis.

This study examines the associations between force and velocity characteristics of forward skating and off-ice speed, agility, and power of highly trained teenage ice hockey players. Players attending the Quebec ice hockey federation's off-season evaluation camp were invited to participate in this study. Final sample consists of 107 highly trained teenage ice hockey players (Males: n = 38; 13.83 ± 0.38 years; Females: n = 69: 14.75 ± 0.90 years). Individual force-velocity profiles (F-V) were determined during a 44 m skating sprint. Off-ice speed, agility, and power were measured using 30 m sprint, 5-10-5 agility, and standing long jump. Associations between F-V mechanical capabilities and off-ice indicators were analyzed with correlational analyses and multivariate analysis of covariance (MANCOVA). Results of pooled data indicate that the three off-ice measures had moderate associations with F 0 and V 0 and large associations with P max . Associations with Rf max , D rf, and S fv were moderate to small. F 0 had stronger associations with off-ice performance in female players while V 0 was more important with male players. MANCOVA identified 5-10-5 times as the better predictor for F 0 while 30 m sprints times better predicted V 0. To maximize physical attributes of skating ability, practitioners are encouraged to focus on a general physical preparation for highly trained teenage players. Prioritizing types of exercises that use change of direction or acceleration and linear speed should have distinct effects on F 0 and V 0 on the ice., (© 2024 The Author(s). European Journal of Sport Science published by Wiley‐VCH GmbH on behalf of European College of Sport Science.)

Background: Precise identification of motion phases in long-track speed skating is critical to characterize and optimize performance. This study aimed to estimate the intra- and inter-rater reliability of movement phase identification using inertial measurement units (IMUs) in long-track speed skating., Methods: We analyzed 15 skaters using IMUs attached to specific body locations during a 500m skate, focusing on the stance phase, and identifying three movement events: Onset, Edge-flip, and Push-off. Reliability was assessed using intraclass correlation coefficients (ICC) and Bland-Altman analysis., Results: Results showed high intra- and inter-rater reliability (ICC [1,1]: 0.86 to 0.99; ICC [2,1]: 0.81 to 0.99) across all events. Absolute error ranged from 0.56 to 6.15 ms and from 0.92 to 26.29 ms for intra- and inter-rater reliability, respectively. Minimally detectable change (MDC) ranged from 17.56 to 62.22 ms and from 33.23 to 131.25 ms for intra- and inter-rater reliability, respectively., Discussion: Despite some additive and proportional errors, the overall error range was within acceptable limits, indicating negligible systematic errors. The measurement error range was small, demonstrating the accuracy of IMUs. IMUs demonstrate high reliability in movement phase identification during speed skating, endorsing their application in sports science for enhanced kinematic studies and training., Competing Interests: The authors declare there are no competing interests., (©2024 Iizuka et al.)

A comprehensive analysis of cross-country skiing races is a pivotal step in establishing effective training objectives and tactical strategies. This study aimed to develop a method of classifying sub-techniques and analyzing skiing characteristics during cross-country skiing skating style timed races on snow using high-precision kinematic GNSS devices. The study involved attaching GNSS devices to the heads of two athletes during skating style timed races on cross-country ski courses. These devices provided precise positional data and recorded vertical and horizontal head movements and velocity over ground (VOG). Based on these data, sub-techniques were classified by defining waveform patterns for G2, G3, G4, and G6P (G6 with poling action). The validity of the classification was verified by comparing the GNSS data with video analysis, a process that yielded classification accuracies ranging from 95.0% to 98.8% for G2, G3, G4, and G6P. Notably, G4 emerged as the fastest technique, with sub-technique selection varying among skiers and being influenced by skiing velocity and course inclination. The study's findings have practical implications for athletes and coaches as they demonstrate that high-precision kinematic GNSS devices can accurately classify sub-techniques and detect skiing characteristics during skating style cross-country skiing races, thereby providing valuable insights for training and strategy development.

Elite athletes in speed roller skates perceive skating to be a more demanding exercise for the groin when compared to other cyclic disciplines, increasing their risk of injury. The objective of this study was to monitor the kinematic and electromyographic parameters of roller speed skaters, linearly, on a treadmill, and to compare different skating speeds, one at 20 km/h and one at 32 km/h, at a 1° inclination. The acquisition was carried out by placing an inertial sensor at the level of the first sacral vertebra, and eight surface electromyographic probes on both lower limbs. The kinematic and electromyographic analysis on the treadmill showed that a higher speed requires more muscle activation, in terms of maximum and average values and co-activation, as it not only increases the intrinsic muscle demand in the district, but also the athlete's ability to coordinate the skating technique. The present study allows us to indicate not only how individual muscle districts are activated during skating on a surface different from the road, but also how different speeds affect the overall district load distributions concerning effective force, which is essential for the physiotherapist and kinesiologist for preventive and conditional purposes, while also considering possible variations in the skating technique in linear advancement.

Background: Sprint skating is essential for competitive success in hockey. Previous studies have highlighted various measures of lower-body strength and power as key factors influencing sprint performance. However, while these studies have indicated a significant association between the ability to exert greater force and impulse into the ice surface, and the capacity to achieve faster sprint skating speeds, the direct relationship between these factors remains largely inferred., Research Question: What are the relationships between insole plantar force variables, sprint skating performance, and their association with physical capacity measures, in national-level male hockey athletes?, Methods: Athletes (n=13) performed 25 m sprint skating trials with insole force sensors and completed: ankle dorsiflexion and hip abduction range-of-motion (ROM), countermovement jump (CMJ), seated single-leg jump, and 10-5 repeated-hop test (RHT) assessments., Results: Relationships were assessed using Kendall's Tau rank correlations (τ), with significant relationships identified between mean relative weight acceptance impulse [WAI] and 0-5 m (τ=0.47) and total distance (τ=0.46) times. Additionally, significant associations were observed between mean relative WAI and: CMJ relative eccentric deceleration impulse (τ=0.44), CMJ eccentric peak velocity (τ=-0.46) and RHT concentric impulse (τ=-0.56). Finally, significant relationships were identified between mean relative PI for all strides and the 10-20 m split, with peak velocity (PV) (τ=-0.58 to -0.73); and between ankle dorsiflexion ROM and PV (τ=-0.57)., Significance: Athletes with faster initial acceleration and overall sprint performance times demonstrated lower relative WAI during their strides and employed a jump strategy that optimized concentric impulse with a rapid eccentric phase. To attain a high PV the athletes appeared to require a stride that maximized glide and minimized vertical force, with greater ankle dorsiflexion ROM potentially facilitating this., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Purpose: Optimal ankle dorsiflexion range of motion plays a vital role in attaining the essential crouched posture necessary for excelling in speed skating. The purpose of this study was to determine how the ankle dorsiflexion angle evolves throughout a day of training and to identify the factors that influence this angle., Methods: Thirty short-track speed skaters, from 2 teams, participated in this study. The maximum ankle dorsiflexion angle was obtained in a lunge position facing a wall, using a digital inclinometer. All measures were obtained 3 times per side, 6 times per day, on 2 training days separated by at least a week. We conducted multiple tests to study the impact of repetition, day, side, team level, sex, and moment on the ankle dorsiflexion angle., Results: The 3 times repeated measures and the 2 days of training did not have a significant influence on the results. There was a statistically significant difference between the first time point of the day and the 5 other time points for both ankles. Moreover, the influence of sex and team level was not statistically significant., Conclusions: The results indicate that there are significant changes in ankle dorsiflexion range of motion but only after the first warm-up of the day. Such findings could enable team staff to enhance athletes' precompetition preparation and tailor ankle mobility training regimens more effectively.

A common theory of motor control posits that movement is controlled by muscle synergies. However, the behavior of these synergies during highly complex movements remains largely unexplored. Skateboarding is a hardly researched sport that requires rapid motor control to perform tricks. The objectives of this study were to investigate three key areas: (i) whether motor complexity differs between skateboard tricks, (ii) the inter-participant variability in synergies, and (iii) whether synergies are shared between different tricks. Electromyography data from eight muscles per leg were collected from seven experienced skateboarders performing three different tricks (Ollie, Kickflip, 360°-flip). Synergies were extracted using non-negative matrix factorization. The number of synergies (NoS) was determined using two criteria based on the total variance accounted for (tVAF > 90% and adding an additional synergy does not increase tVAF > 1%). In summary: (i) NoS and tVAF did not significantly differ between tricks, indicating similar motor complexity. (ii) High inter-participant variability exists across participants, potentially caused by the low number of constraints given to perform the tricks. (iii) Shared synergies were observed in every comparison of two tricks. Furthermore, each participant exhibited at least one synergy vector, which corresponds to the fundamental 'jumping' task, that was shared through all three tricks., (© 2024. The Author(s).)

Abstract: Keiner, M, Kierot, M, Stendahl, M, Brauner, T, and Suchomel, TJ. Maximum strength and power as determinants of match skating performance in elite youth ice hockey players. J Strength Cond Res 38(6): 1090-1094, 2024-Maximum strength has a strong influence on speed-strength performances such as sprints and jumps. Important for sports practice is whether these findings are also reflected in game performance. Therefore, the aim of this study was to explore the influence of maximum strength and power performance on linear on-ice skating performance in testing and during game play. A cross-sectional study was conducted, and 24 highly trained male youth ice hockey players participated. Jump performances (countermovement jump [CMJ], drop jumps), maximum strength (1 repetition maximum [1RM] squat and isometric trap bar pull [ITBP]), and on-ice linear sprints (15 m [LS15], 30 m [LS30], flying 15 m [FLY15]) were measured. Match performances (among others: peak skating speed) were collected of 4 regular league games using a local positioning system. Correlation coefficient and explained variance were calculated ( ρ ≤ 0.05). Correlations between maximum strength and jump with on-ice linear sprint performance showed 1-35% explained variance. Correlations between "off ice" test (CMJ, relative 1RM) and game data (peak skating speed) showed 22-30% explained variance, respectively, while ITBP and DJ missed significant level. Between linear sprint and game performance showed 15-59% explained variance. In this study, a clear influence of 1RM in squatting and CMJ performance on on-ice linear sprint as well as in-game peak skating speed was observed. These findings show that strength and jumping performance can be valuable tests within a comprehensive test battery and indicate the relevance of strength and jumping tasks within the regular exercise program to improve in-game skating performance., (Copyright © 2024 National Strength and Conditioning Association.)

Background: The inclusion of skateboarding in the Olympics suggests that athletes and coaches are seeking ways to enhance their chances of succeeding on the world stage. Understanding what constitutes performance, and what physical, neuromuscular, and biomechanical capacities underlie it, is likely critical to success., Objective: The aim was to overview the current literature and identify knowledge gaps related to competitive skateboarding performance and associated physical, technical, and tactical demands of Olympic skateboarding disciplines., Methods: A systematic scoping review was performed considering the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (Extension for Scoping Reviews) guidelines. Data sources were MEDLINE (Ovid), Scopus, SPORTDiscus, and PubMed. We included all peer-reviewed literature after 1970 describing the physiological, neuromuscular, biomechanical, and/or tactical aspects of skateboarding., Results: Nineteen original articles explored the physiological (n = 9), biomechanical (n = 8), and technical (n = 10) demands of skateboarding. No research explored the tactical demands of competition. Moreover, although competitive males (n = 2 studies) and females (n = 1 study) were recruited as participants, no research directly related skateboarding demands to performance success in competitive environments., Conclusions: Ultimately, what constitutes and distinguishes competitive skateboarding is unexplored. There is some evidence indicating aspects of the sport require flexibility and elevated and fast force output of the lower limbs, which may be valuable when attempting to maximise ollie height. Nonetheless, a lack of ecological validity, such as using static ollie tests as opposed to rolling, restricted our ability to provide practical recommendations, and inconsistency of terminology complicated delineating discipline-specific outcomes. Future researchers should first look to objectively identify what skaters do in competition before assessing what qualities enable their performance., (© 2024. The Author(s).)

Purpose: In this study, we compared the influence of movement specificity during velocity-load jump testing to predict on-ice acceleration performance in elite speed skaters., Methods: Elite long-track speed skaters (N = 27) performed velocity-load testing with 3 external loads during unilateral horizontal jumping, lateral jumping, and bilateral vertical countermovement jumping. For the unilateral tests, external load conditions were set to 10 N, 7.5% and 15% of external load relative to body weight. For the countermovement jumping, load conditions were body weight and 30% and 60% of external load relative to body weight. On-ice performance measures were obtained during maximal 50-m accelerations from a standing start, including maximal skating speed, maximal acceleration capacity, and maximum horizontal power. The 100-m split time from a 500-m race was also obtained. Regularized regression models were used to identify the most important predictors of on-ice acceleration performance. In addition to regularized regression coefficients, Pearson correlation coefficients (r) were calculated for all variables retained by the model to assess interrelationships between single predictors and on-ice performance measures., Results: The countermovement jump with 30% of body mass demonstrated the strongest association with maximal skating speed, maximum horizontal power, and 100-m time (regularized regression coefficient = .16-.49, r = .84-.97, P < .001). Horizontal jump with 15% of body mass was the strongest predictor of maximal acceleration capacity performance (regularized regression coefficient = .08, r = .83, P < .001)., Conclusions: The findings of this study suggest that mechanical specificity rather than movement specificity was more relevant for predicting on-ice acceleration performance.

Abstract: Dietze-Hermosa, MS, Montalvo, S, Gonzalez, MP, and Dorgo, S. The impact of an 8-week, resisted, sprint training program on ice skating performance in male youth ice hockey players. J Strength Cond Res 38(5): 957-965, 2024-The purposes of this randomized control study were to (a) compare the effects of an on-ice versus an overground resisted sprint training intervention and a control condition and (b) identify changes in ice skating kinematics and kinetics after training intervention participation. Twenty-four youth ice hockey players were randomly allocated into 3 groups: (a) on-ice resisted sprint training (on-ice RST); (b) overground resisted sprint training (overground RST); and (c) body weight resistance training (control). During the 8-week intervention, the 2 RST groups engaged in sled towing methods, whereas the control group engaged in a body weight resistance training program twice a week. A series of individual, repeated-measures analysis of variances with post hoc pairwise comparisons were conducted for variables of interest. An interaction effect was noted for ice skating s-cornering agility drill completion time ( p = 0.01; ηp2 = 0.36), ice skating 30-m top speed completion time ( p = 0.04; ηp2 = 0.27), step length ( p = 0.04; ηp2 = 0.26), and knee angle at touchdown ( p = 0.03; ηp2 = 0.30). The on-ice RST group displayed superior improvements across ice skating tests compared with the control group. Data show that on-ice RST has the greatest transfer effect to ice skating metrics; however, improvements in certain ice skating metrics can be observed with overground training also., (Copyright © 2024 National Strength and Conditioning Association.)

Skateboarding, once regarded primarily as a means of transportation and entertainment for youth, has become a recognized professional sport, gaining global popularity. With its recent inclusion in the Olympics, a growing imperative exists to comprehensively understand biomechanics explaining skateboarding performance. This literature review seeks to consolidate knowledge within this domain, focusing on experimental and modeling studies about skateboard riding and tricks. The criteria for study selection encompassed content relevance and publication year, spanning from the last two decades and extending further back to 1980 following cross-referencing of seminal works. Peer-reviewed journal articles, conference proceedings, and books were considered, with comprehensive searches conducted on electronic databases, including SCOPUS, PubMed, Scielo, and Taylor & Francis. Comprehending the biomechanical facets of skateboarding is essential in promoting its use and ensuring safety among all practitioners. Insights into factors such as body kinetics, kinematics, and muscle activation represent a foundational step toward understanding the nuances of this sport with implications for both clinical and biomechanical research. Modern data collection systems such as inertial measurement units (IMU) and electromyography (EMG) offer unprecedented insights into human performance during skateboarding, such as joint range of motion, coordination, and muscle activation, whether in casual riding or executing complex tricks and maneuvers. Developing robust modeling approaches also holds promise for enhancing skateboarding training and performance. Crucially, these models can serve as the initial framework for understanding injury mechanisms and implementing strategies to improve performance and mitigate injury risks.

Ice hockey is an intense team sport characterized by repeated bursts of fast-paced skating, rapid changes in speed and direction and frequent physical encounters. These are performed in on-ice shifts of ~30-80 s interspersed with longer sequences of passive recovery, resulting in about 15-25 min on-ice time per player. Nearly 50% of the distance is covered at high-intensity skating speeds and with an accentuated intense activity pattern in forwards compared to defensemen. During ice hockey match-play, both aerobic and anaerobic energy systems are significantly challenged, with the heart rate increasing toward maximum levels during each shift, and with great reliance on both glycolytic and phosphagen ATP provision. The high-intensity activity pattern favors muscle glycogen as fuel, leading to pronounced reductions despite the relatively brief playing time, including severe depletion of a substantial proportion of individual fast- and slow-twitch fibers. Player-tracking suggests that the ability to perform high-intensity skating is compromised in the final stages of a game, which is supported by post-game reductions in repeated-sprint ability. Muscle glycogen degradation, in particular in individual fibers, as well as potential dehydration and hyperthermia, may be prime candidates implicated in exacerbated fatigue during the final stages of a game, whereas multiple factors likely interact to impair exercise tolerance during each shift. This includes pronounced PCr degradation, with potential inadequate resynthesis in a proportion of fast-twitch fibers in situations of repeated intense actions. Finally, the recovery pattern is inadequately described, but seems less long-lasting than in other team sports., (© 2022 The Authors. Scandinavian Journal of Medicine & Science In Sports published by John Wiley & Sons Ltd.)

This paper studies the tactical decision-making model of short track speed skating based on deep reinforcement learning, so as to improve the competitive performance of corresponding short track speed skaters. Short track speed skating, a traditional discipline in the Winter Olympics since its establishment in 1988, has consistently garnered attention. As artificial intelligence continues to advance, the utilization of deep learning methods to enhance athletes' tactical decision-making capabilities has become increasingly prevalent. Traditional tactical decision techniques often rely on the experience and knowledge of coaches and video analysis methods that require a lot of time and effort. Consequently, this study proposes a scientific simulation environment for short track speed skating, that accurately simulates the physical attributes of the venue, the physiological fitness of the athletes, and the rules of the competition. The Double Deep Q-Network (DDQN) model is enhanced and utilized, with improvements to the reward function and the distinct description of four tactics. This enables agents to learn optimal tactical decisions in various competitive states with a simulation environment. Experimental results demonstrate that this approach effectively enhances the competition performance and physiological fitness allocation of short track speed skaters.

Mechanical power is a key performance indicator in long track speed skating. Maximal power output in athletic performance can be achieved when mechanical properties of muscles, such as the force-length relationship, are optimized. The purpose of this study was to determine the in vivo operating range of vastus lateralis (VL) fascicle lengths during speed skating imitation and compare the fascicle lengths to those that define the VL force-length relationship. Sixteen sub-elite long track speed skaters (7 females and 9 males; body mass: 72.5 [11.5] kg; age: 22.1 [2.7] years) performed maximal voluntary isometric knee extensions at nine different knee joint positions (20-120°) on the left leg to obtain the maximal vastus lateralis (VL) force-length relationship. Participants then performed a speed skating imitation exercise, the turn-cable, at three progressive perceived efforts (50%, 75%, 100%) to identify the VL fascicle excursion during a complete imitation skating stroke. Fascicle lengths and knee joint angles were examined at initial-contact, peak EMG, and take-off. Fascicles between initial contact and peak EMG covered the descending limb of both the maximal and submaximal force-length relationships while operating over the plateau region from peak EMG to take-off. We conclude that the VL works at sub-optimal length during the gliding phase of skating, but at optimal length for maximal force production during the crucial push-off phase where propulsion is provided., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Objective: Skater's cramp is a debilitating disorder in expert speedskaters and recent evidence from muscle and movement studies nominate it is a task-specific dystonia (TSD). Building on these studies we investigated clinical features and personality in skater's cramp, hypothesizing that similar to other TSDs, trait emotionality would be higher in affected skaters., Methods: In a cross-sectional study we employed the HEXACO inventory to examine the personality of a cohort of skaters with skater's cramp (n = 26) compared to age, sex, and experience-matched controls (n = 28). Affected skaters were selected based on relevant clinical features important to the diagnosis of TSD., Results: Sentimentality (a sub-factor of emotionality) was higher in affected skaters, but only in the male population. Extraversion was lower in skaters with skater's cramp. Clinical findings resembled other forms of TSD., Discussion: Higher sentimentality is in line with previous studies in TSD. Lower Extraversion in affected skaters was an unexpected finding that may be a new feature of skater's cramp and TSD. Due to our small sample size and cross-sectional design, these findings are preliminary, but offer tentative evidence of personality differences in skater's cramp in line with TSD., Competing Interests: Declaration of Competing Interest None., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Purpose: Short-track speed skating race distances of 500, 1000, and 1500 m that last ∼40 seconds to ∼2.5 minutes and require a maximal intensity at speeds beyond maximal oxygen uptake (VO2max). Recently, the anaerobic speed reserve (ASR) has been applied by scientists and coaches in middle-distance sports to deepen understanding of 1- to 5-minute event performance where different physiological profiles (speed, hybrid, and endurance) can have success., Methods: World-class (women, n = 2; men, n = 3) and international-level (women, n = 4; men, n = 5) short-track speed skaters completed maximal aerobic speed and maximal skating speed tests. ASR characteristics were compared between profiles and associated with on-ice performance., Results: World-class athletes raced at a lower %ASR in the 1000- (3.1%; large; almost certainly) and 1500-m (1.8%; large; possibly) events than international athletes. Men's and women's speed profiles operated at a higher %ASR in the 500-m than hybrid and endurance profiles, whereas in the 1500-m, endurance profiles worked at a substantially lower %ASR than hybrid and speed profiles. Women's 500-m performance is very largely associated with maximal skating speed, while women's maximal aerobic speed appears to be a key determining factor in the 1000- and 1500-m performance., Conclusion: World-class short-track speed skaters can be developed in speed, hybrid, and endurance profiles but achieve their performance differently by leveraging their strongest characteristics. These results show nuanced differences between men's and women's 500-, 1000- and 1500-m event performance across ASR profile that unlock new insights for individualizing athlete performance in these disciplines.

Abstract: Han, J, Liu, M, Shi, J, and Li, Y. Construction of a machine learning model to estimate physiological variables of speed skating athletes under hypoxic training conditions. J Strength Cond Res 37(7): 1543-1550, 2023-Monitoring changes in athletes' physiological variables is essential to create a safe and effective hypoxic training plan for speed skating athletes. This research aims to develop a machine learning estimation model to estimate physiological variables of athletes under hypoxic training conditions based on their physiological measurements collected at sea level. The research team recruited 64 professional speed skating athletes to participate in a 10-week training program, including 3 weeks of sea-level training, followed by 4 weeks of hypoxic training and then a 3-week sea-level recovery period. We measured several physiological variables that could reflect the athletes' oxygen transport capacity in the first 7 weeks, including red blood cell (RBC) count and hemoglobin (Hb) concentration. The physiological variables were measured once a week and then modeled as a mathematical model to estimate measurements' changes using the maximum likelihood method. The mathematical model was then used to construct a machine learning model. Furthermore, the original data (measured once per week) were used to construct a polynomial model using curve fitting. We calculated and compared the mean absolute error between estimated values of the 2 models and measured values. Our results show that the machine learning model estimated RBC count and Hb concentration accurately. The errors of the estimated values were within 5% of the measured values. Compared with the curve fitting polynomial model, the accuracy of the machine learning model in estimating hypoxic training's physiological variables is higher. This study successfully constructed a machine learning model that used physiological variables measured at the sea level to estimate the physiological variables during hypoxic training., (Copyright © 2023 National Strength and Conditioning Association.)

Objective: Skater's cramp is a movement disorder in speed skaters. We investigated whether affected skaters matched the disease profile of task-specific dystonia, specifically whether there was evidence of maladaptive muscle activity occurring simultaneously with aberrant movements (jerking). We further examined different skating intensities, positing no change would be more indicative of task-specific dystonia., Methods: We analyzed video, kinematic and muscle activity in 14 affected skaters. We measured the angular velocity and electromyographic activity of normalized speed skating strokes using one dimensional statistical non-parametric mapping. Skaters were matched with comparably skilled controls, and filled out a bespoke clinical questionnaire., Results: Skaters' impacted leg showed over-activation in the peroneus longus, tibialis anterior and gastrocnemius that coincided with higher foot movement compared to their healthy leg and controls. This pattern persisted regardless of skating intensity. Clinical features indicated it was task-specific and painless with common trigger factors including stress, equipment change, and falling., Conclusions: We showed aberrant muscular and kinematic activity in a movement disorder in speed skaters indicative of task-specific dystonia., Significance: Understanding skater's cramp as a task-specific dystonia could reduce the damage that misdiagnosis and unsuccessful invasive operations have caused. Our quantitative method has value in testing future treatment efficacy., (Copyright © 2023 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Purpose: In short-track speed skating, athletes need to possess specific physiological capabilities to perform explosive starts and to finish races with faster lap times than their opponents. Repeated-sprint training in hypoxia (RSH) can enhance repeated-sprint ability and high-intensity performance. This study aimed to evaluate the relationship between on- and off-ice performance indicators for training and testing purposes and how these are optimized with RSH in world-class short-track speed skaters including world and Olympic champions., Methods: RSH training was administered for 3 consecutive weeks, 3 times per week, at 3500 m of simulated altitude. Testing sessions (on-ice: 3-lap, 27-lap; off-ice: cycling incremental test, 7-s and 30-s Wingate) were performed immediately before and 2 and 4 weeks after RSH to determine the time course of decay., Results: On-ice top speed showed a small and possibly beneficial change of ∼0.9% for the women and large and almost certain ∼0.7% improvement for the men 2 weeks post-RSH. Cycling peak power showed a moderate and probable ∼5.4% improvement for the men 2 weeks after RSH. These adaptations reverted to baseline 4 weeks post-RSH. Wingate average power showed a small and possibly beneficial gain (∼3.4%) in performance 4 weeks post-RSH., Conclusion: Although scientific controls could not be added due to the extremely high caliber of these athletes and low sample size of the national team, this study suggests that cycling RSH can be added immediately after on-ice training and can transfer into meaningful improvements on the ice in both male and female skaters.

Drafting is distinctive for team pursuit races in long-track speed skating. This study aims to compare the impact of drafting on physical intensity (heart rate [HR]) and perceived intensity (ratings of perceived exertion [RPE]) per drafting position. Eighteen skilled male ( n  = 9) and female ( n  = 9) skaters (20.0 ± 4.8 years) skated three trials, in first, second or third position, with consistent average velocity (F 2,10  = 2.30, p  = 0.15, η p 2  = 0.32). Differences in HR and RPE (Borg CR-10 scale) were compared within-subjects (three positions) using a repeated-measures ANOVA ( p  < 0.05). Compared to the first position, HR was lower in the second (benefit 3.2%) and third (benefit 4.7%) position and lower in third compared to second position (benefit 1.5%), observed in 10 skaters (F 2,28  = 28.9, p  < 0.001, η p 2 = 0.67). RPE was lower when comparing second (benefit 18.5%) and third (benefit 16.8%) position to first (F 1.3,22.1  = 7.02, p  < 0.05, η p 2 = 0.29) and similar for third and second positions., observed in 8 skaters. Even though the physical intensity was lower when drafting in third versus second position, the perceived intensity was equal. There were large interindividual differences between skaters. Coaches are advised to adopt a multidimensional, tailored approach when selecting and training skaters for a team pursuit.

Aerobic capacity is important for speed skaters to achieve good results in middle-long distance events. The technical characteristics of speed skating cause intermittent blood flow blockage in the lower limbs. Therefore, an athlete's aerobic capacity on ice may differ from that measured by cycling or running. Now, the on-ice aerobic capacity lacks methods for conducting aerobic capacity tests on ice. Objective: The objective of this study was to develop a method for measuring on-ice aerobic capacity for young athletes and to compare it with the VO 2max test on cycling. Methods: This study established a test method for the on-ice aerobic capacity of young, high-level speed skaters with incremental load (on-ice incremental skating test, OIST) through expert interviews and literature review. In the first part, OIST was used to test the aerobic abilities of 65 youth professional speed skaters (51 males and 14 females) on ice and to explore the correlation with their specific performance. The second part compares the relationship between aerobic capacity on ice and aerobic capacity on bicycle of 18 young high-level male athletes. The third part establishes the regression formula of ice ventilation threshold heart rate. The OIST established in this study can evaluate the on-ice aerobic capacity of athletes from National Level and Level 1&2 in China. The athletes' on-ice aerobic capacity indicators were significantly lower than those of the cycling test. However, the values of absolute VO 2max and absolute ventilatory threshold had a high correlation (R = 0.532, p < 0.05; R = 0.584, p < 0.05). The regression formula of ventilatory threshold heart rate on ice = 0.921 × HRmax (Cycling test) -9.243. The OIST established in this study meets the characteristics and requirements of the VO 2max measurement method. The OIST seems to be able to better evaluate the aerobic capacity of athletes skating on ice. The indicators of maximum oxygen uptake and ventilation threshold in OIST were significantly lower than those in the aerobic cycling test, but there was a good correlation. The aerobic cycling test can be used as an important selection index of the ice aerobic capacity of speed skaters. The regression formula will provide an important basis for coaches to accurately monitor the intensity of ice training.

Introduction: Skater's cramp is a career-ending movement disorder in expert speed skaters noted to be a likely task-specific dystonia. In other movement disorders, including task-specific dystonia, studies have found evidence of central dysregulation expressed as higher inter-muscular coherence. We looked at whether inter-muscular coherence was higher in affected skaters as a possible indicator that it is centrally driven, and by extension further evidence it is a task-specific dystonia., Methods: In 14 affected and 14 control skaters we calculated inter-muscular coherence in the theta-band in a stationary task where tonic muscle activation was measured at 10%, 20% and 50% of maximum voluntary contraction. Additionally, we calculated wavelet coherence while skating at key moments in the stroke cycle., Results: Coherence did not differ in the stationary activation task. While skating, coherence was higher in the impacted leg of affected skaters compared to their non-impacted leg, p = .05, η 2  = 0.031, and amplitude of electromyography correlated with coherence in the impacted leg, p = .009, R 2 adjusted  = 0.41. A sub-group of severely affected skaters (n = 6) had higher coherence in the impacted leg compared to the left and right leg of controls, p = .02, Cohen's d = 1.59 and p = .01, Cohen's d = 1.63 respectively. Results were less clear across the entire affected cohort probably due to a diverse case-mix., Conclusion: Our results of higher coherence in certain severe cases of skater's cramp is preliminary evidence of a central dysregulation, making the likelihood it is a task-specific dystonia higher., Competing Interests: Declaration of competing interest None., (Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Abstract: Conners, RT, Whitehead, PN, Dodds, FT, Schott, KD, and Quick, MC. Validation of the polar team pro system for sprint speed with ice hockey players. J Strength Cond Res 36(12): 3468-3472, 2022-Commercially available player tracking sensors such as the Polar Team Pro system (PTPS) have been used to monitor athlete performance. Use during ice hockey practices and games has resulted in seemingly plausible and valid values for internal metrics (heart rate); however, external metrics (distance, speed, and acceleration) seem sporadic and counterintuitive. To determine the validity of the PTPS for measuring sprint speed with collegiate hockey players, 15 NCAA Division I male athletes (21.86 ± 1.04 years, 175.86 ± 6.78 cm, 80.58 ± 4.44 kg) participated in the study. Subjects wore a PTPS strap, at the level of the xiphoid process, and performed 2 sprints of 15.24 m (blue line to blue line) and 35.05 m (red line to the far blue line) in 3 conditions: indoor ice skating, indoor running, and outdoor running. Timing gates (TG) were used to determine sprint times, which allowed for manual calculation of speed. Speed values from the PTPS and TG were compared using paired-samples t -tests, and an alpha level of 0.05, 2-sided, was set a priori as a significance level. For indoor ice skating, PTPS significantly underestimated speeds at both distances ( p < 0.001). However, PTPS significantly overestimated speeds for indoor and outdoor sprints at both distances ( p ≤ 0.001). The PTPS is not accurate for measuring short-distance linear sprint speed or linear sprint speed during indoor ice skating. The inconsistency in speed values needs to be taken into consideration when using the system for science-based training because inaccurate speed values may negatively affect other external performance metrics provided by PTPS., (Copyright © 2020 National Strength and Conditioning Association.)

The aim of this observational study was to examine the differences between training variables as intended by coaches and perceived by junior speed skaters and to explore how these relate to changes in stress and recovery. During a 4-week preparatory period, intended and perceived training intensity (RPE) and duration (min) were monitored for 2 coaches and their 23 speed skaters, respectively. The training load was calculated by multiplying RPE by duration. Changes in perceived stress and recovery were measured using RESTQ-sport questionnaires before and after 4 weeks. Results included 438 intended training sessions and 378 executed sessions of 14 speed skaters. A moderately higher intended (52:37 h) versus perceived duration (45:16 h) was found, as skaters performed fewer training sessions than anticipated (four sessions). Perceived training load was lower than intended for speed skating sessions (-532 ± 545 AU) and strength sessions (-1276 ± 530 AU) due to lower RPE scores for skating (-0.6 ± 0.7) or shorter and fewer training sessions for strength (-04:13 ± 02:06 hh:mm). All training and RESTQ-sport parameters showed large inter-individual variations. Differences between intended-perceived training variables showed large positive correlations with changes in RESTQ-sport, i.e., for the subscale's success ( r = 0.568), physical recovery ( r = 0.575), self-regulation ( r = 0.598), and personal accomplishment ( r = 0.589). To conclude, speed skaters that approach or exceed the coach's intended training variables demonstrated an increased perception of success, physical recovery, self-regulation, and personal accomplishment.

Abstract: Thompson, KM, Safadie, A, Ford, J, and Burr, JF. Off-ice resisted sprints best predict all-out skating performance in varsity hockey players. J Strength Cond Res 36(9): 2597-2601, 2022-Off-ice fitness testing is commonly used to predict the physiological abilities of ice-hockey players. Although there is a notable association between certain off-ice tests of jump power and anaerobic capacity with on-ice skating acceleration ( r = 0.3-0.7), it is likely that off-ice tests which more closely resemble the demands of skating will have better predictive ability of this skill. The aim of the current study was to compare the suitability of common off-ice fitness tests and off-ice resisted sprints for predicting 15-m on-ice skate time. Male and female varsity-level hockey players performed a battery of common off-ice fitness tests, resisted sprints, and on-ice 15-m sprints over 3 testing days. At least moderate correlations between off-ice tests and on-ice sprints were observed for all common fitness tests (all p ≤ 0.002): Wingate peak power ( r = -0.65), Wingate fatigue rate ( r = -0.53), vertical jump ( r = -0.52), and broad jump ( r = -0.61), with resisted sprint tests showing the strongest associations (off-ice 15-kg resisted sprint ( r = 0.79) and off-ice 30-kg resisted sprint ( r = 0.74)). In multivariate analysis, stepwise regression revealed the 15-kg resisted sprint as the sole meaningful predictor of on-ice sprint time ( R = 0.79, R2 = 0.62; p ≤ 0.001). We conclude that resisted off-ice sprints have better predictive ability of on-ice skate time compared with commonly used off-ice tests. Resisted sprinting can be used by strength and conditioning staff as an indicator of on-ice acceleration ability during periods of limited access to on-ice facilities or as a component of fitness testing., (Copyright © 2020 National Strength and Conditioning Association.)

Abstract: Roete, AJ, Stoter, IK, Lamberts, RP, Elferink-Gemser, MT, and Otter, RTA. Introducing a method to quantify the specificity of training for races in speed skating. J Strength Cond Res 36(7): 1998-2004, 2022-The specificity of training for races is believed to be important for performance development. However, measuring specificity is challenging. This study aimed to develop a method to quantify the specificity of speed skating training for sprint races (i.e., 500 and 1,000 m), and explore the amount of training specificity with a pilot study. On-ice training and races of 10 subelite-to-elite speed skaters were analyzed during 1 season (i.e., 26 weeks). Intensity was mapped using 5 equal zones, between 4 m·s-1 to peak velocity and 50% to peak heart rate. Training specificity was defined as skating in the intensity zone most representative for the race for a similar period as during the race. During the season, eight 500 m races, seven 1,000 m races, and 509 training sessions were analyzed, of which 414 contained heart rate and 375 sessions contained velocity measures. Within-subject analyses were performed. During races, most time was spent in the highest intensity zone (Vz5 and HRz5). In training, the highest velocity zone Vz5 was reached 107 ± 28 times, with 9 ± 3 efforts (0.3 ± 0.1% training) long enough to be considered 500 m specific, 6 ± 5 efforts (0.3 ± 0.3% training) were considered 1,000 m specific. For heart rate, HRz5 was reached 151 ± 89 times in training, 43 ± 33 efforts (1.3 ± 0.9% training) were considered 500 m specific, and 36 ± 23 efforts (3.2 ± 1.7% training) were considered 1,000 m specific. This newly developed method enables the examination of training specificity so that coaches can control whether their intended specificity was reached. It also opens doors to further explore the impact of training specificity on performance development., (Copyright © 2022 National Strength and Conditioning Association.)

A figure skating jump score is determined by the sum of the base value based on the difficulty and grade of execution (GOE) that indicates the performance quality. Therefore, performing a high-quality jump to obtain a high GOE is essential to win a competition. However, the relationship between the GOE and kinematic parameters remains unclear. We analysed the horizontal distance, vertical height, and landing speed of double axel jumps in the Ladies' Short Program at the 2019 World Championships. The highest GOE group had significantly larger horizontal distances than the middle and lower groups, while the landing speed and vertical height were not significantly different. A principal component regression analysis was conducted to clarify the contrast between the three variables affecting the GOE. The results showed that greater horizontal distance and landing speed compared to vertical height (component 1) and greater horizontal distance compared to landing speed (component 3) contributed to higher GOE. We divided skaters into four clusters using these two components and provided general GOE acquisition strategies for each cluster. Finally, to apply our results to the industry, we proposed two new evaluation indicators which are highly correlated with the two components and easy to interpret.

We measured the level of natural antibodies (nAb) to glutamate and GABA reflecting the balance of excitation and inhibition systems and involved in the adaptation processes in athletes receiving normalized physical activity in the dynamics of training (figure skaters, football players, and people actively involved in sports). It was found that each subject has an individual immunological profile and its parameters change in accordance with the training load. The measured levels of nAbs to GABA and glutamate correlate the physical activity of a person. The surveyed football players were divided into 3 groups according to the results of the analysis. Subjects of the first group had reliably high immunological indices in comparison with the control and were at the peak of physical form; in the third group, low immunological indices relative to the control indicated exhaustion and fatigue. The indicators of the second group corresponded to normal and demonstrated the resource of adaptation to load. The developed method can be used for assessing person's readiness for physical activity., (© 2021. Springer Science+Business Media, LLC, part of Springer Nature.)

Purpose: In long-track speed skating, drafting is a commonly used phenomenon in training; however, it is not allowed in time-trial races. In speed skating, limited research is available on the physical and psychological impact of drafting. The aim of this study was to determine the influence of "skating alone," "leading," or "drafting" on physical intensity (heart rate and blood lactate) and perceived intensity (perceived exertion) of speed skaters., Methods: Twenty-two national-level long-track speed skaters with a mean age of 19.3 (2.6) years skated 5 laps, with similar external intensity in 3 different conditions: skating alone, leading, or drafting. Repeated-measures analysis of variance showed differences between the 3 conditions, heart rate (F2,36 = 10.546, P < .001), lactate (F2,36 = 12.711, P < .001), and rating of perceived exertion (F2,36 = 5.759, P < .01)., Results: Heart rate and lactate concentration were significantly lower (P < .001) when drafting compared with leading (heart rate Δ = 7 [8] beats·min-1, 4.0% [4.7%]; lactate Δ = 2.3 [2.3] mmol/L, 28.2% [29.9%]) or skating alone (heart rate Δ = 8 [7.1] beats·min-1, 4.6% [3.9%]; lactate Δ = 2.8 [2.5] mmol/L, 33.6% [23.6%]). Rating of perceived exertion was significantly lower (P < .01) when drafting (Δ = 0.8 [1.0], 16.5% [20.9%]) or leading (Δ = 0.5 [0.9], 7.7% [20.5%]) versus skating alone., Conclusions: With similar external intensity, physical intensity, as well as perceived intensity, is reduced when drafting in comparison with skating alone. A key finding of this study is the psychological effect: Skating alone was shown to be more demanding than leading, whereas leading and drafting were perceived to be similar in terms of perceived exertion. Knowledge about the reduction of internal intensity for a drafting skater compared with leading or skating alone can be used by coaches and trainers to optimize training conditions.

Mathematical models are used to describe and predict the effects of training on performance. The initial models are structured by impulse-type transfer functions, however, cellular adaptations induced by exercise may exhibit exponential kinetics for their growth and subsequent dissipation. Accumulation of exercise bouts counteracts dissipation and progressively induces structural and functional changes leading to performance improvement. This study examined the suitability of a model with exponential terms (Exp-Model) in elite short-track speed (ST) skaters. Training loads and performance evolution from fifteen athletes (10 males, 5 females) were previously collected over a 3-month training period. Here, we computed the relationship between training loads and performance with Exp-Model and compared with previous results obtained with a variable dose-response model (Imp-Model). Exp-Model showed a higher correlation between actual and modelled performances (R 2  = 0.83 ± 0.08 and 0.76 ± 0.07 for Exp-Model and Imp-Model, respectively). Concerning model parameters, a higher τ A 1 (time constant for growth) value was found (p = 0.0047; d = 1.4; 95% CI [0.4;1.9]) in males compared to females with Exp-model, suggesting that females have a faster adaptative response to training loads. Thus, according to this study, Exp-model may better describe training adaptations in elite ST athletes than Imp-Model.

There has been minimal work examining kinematics of ice hockey wrist shots. The objective was to determine if puck and blade speed were related to trunk rotation during wrist shots in elite and recreational players. Elite (n = 10) and recreational (n = 10) ice hockey players completed wrist shots while skating and from a stationary position on real ice. A 14 camera motion capture system collected kinematic data for the trunk, pelvis, stick, and puck. Dependent variables included peak puck and blade speeds. Independent variables included peak trunk rotation angles, trunk rotation range of motion (ROM), and group (elite vs. recreational). Hierarchical linear models compared relationships between dependent and independent variables for both skating and stationary wrist shots. Greater peak trunk rotation away from the net was related (p < 0.05) to faster puck and blade speeds for skating and stationary wrist shots. This relationship was stronger in the recreational group for skating wrist shots (p < 0.01). Greater trunk rotation ROM was related (p = 0.01) to faster puck and blade speeds for the skating wrist shots only. Coaches should encourage players to increase trunk rotation away from the net during wrist shots, especially in recreational players.

This study aimed to investigate the correlations between players' mechanical capacities determined during off- and on-ice tests. Whole body force-velocity relationships were assessed in elite female ice hockey players ( n  = 17) during jumping [squat jump (SJ)], running (5 and 30 m) and skating (5 and 40 m) sprint tasks. Mechanical capacities estimates include relative maximal theoretical force (F 0rel ), velocity (V 0 ), power (P maxrel ), slope of the linear relationship between force relative to body mass and velocity (S FVrel ), maximal horizontal component of the ground reaction force to the corresponding resultant force (RF max ) and minimal rate of decrease of this ratio (D RF ). On-ice mechanical capacities (F 0rel , P maxrel , RF max and D RF ) largely- to- very largely correlated with 40-m skating split time ( r ranging from 0.82 for D RF to -0.91 for P maxrel ; p  < 0.001). Performance variables (SJ height, 30-m running and 40-m forward skating split time) and P maxrel demonstrated the largest associations between jumping, running and skating tasks ( r ranging from -0.81 for 30-m sprint running time to 0.92 for SJ height; p  < 0.001). Small (V 0 , S FVrel , D RF and force-velocity deficit) to very large (P maxrel ) correlations ( r ranging from 0.58 to 0.72; p  < 0.05) were obtained between mechanical variables inferred from off- and on-ice force-velocity tests. The capacity to generate high amounts of horizontal power and effective horizontal force during the first steps on the ice is paramount for forward skating sprint performance. Mechanical capacities determined during forward skating sprint could be considered in ice hockey testing to identify fitness and/or technical/training requirements.

Background: The demands of elite rink hockey competition are unknown to coaches, although nowadays the explosion of tracking technology makes it possible to fill this research gap. The aims of this study were twofold: firstly, to describe the external load demands involved in a rink hockey match and secondly, to ascertain whether there were differences between exterior (EX) and interior or forward (IN) player positions., Methods: A retrospective observational study was conducted between 2017 and 2018 competitive season. Eight professional players (6 EX and 2 IN) participated voluntarily in the study during 9 official matches. Data logging was performed with a local positioning system and the variables studied were distance covered (DT), distance covered above 18 km/h (HSS), player load (PL), number of high-intensity accelerations (ACC) and number of high-intensity decelerations (DEC)., Results: The average values per player were 4646±1135 m of DT for EX and 4919±1374 for IN, 897±252 m of HSS for EX and 981±313 for IN (mean ±SD); 173±69 and 167.5±57.5 ACC for EX and IN, respectively, and 164±56 and 152.5±42 DEC for EX and IN, respectively (median±IQR); and there were no significant differences (P>0.05), between positions., Conclusions: The findings of this study allow us to ascertain the external load in matches and that EX and IN did not present different physical demands. With this information, coaches can adjust training loads more accurately.

Allisse, M, Bui, HT, Léger, L, Comtois, A-S, and Leone, M. Updating the skating multistage aerobic test and correction for V[Combining Dot Above]O2max prediction using a new skating economy index in elite youth ice hockey players. J Strength Cond Res 34(11): 3182-3189, 2020-A number of field tests, including the skating multistage aerobic test (SMAT), have been developed to predict V[Combining Dot Above]O2max in ice hockey players. The SMAT, like most field tests, assumes that participants who reach a given stage have the same oxygen uptake, which is not usually true. Thus, the objectives of this research are to update the V[Combining Dot Above]O2 values during the SMAT using a portable breath-by-breath metabolic analyzer and to propose a simple index of skating economy to improve the prediction of oxygen uptake. Twenty-six elite hockey players (age 15.8 ± 1.3 years) participated in this study. The oxygen uptake was assessed using a portable metabolic analyzer (K4b) during an on-ice maximal shuttle skate test. To develop an index of skating economy called the skating stride index (SSI), the number of skating strides was compiled for each stage of the test. The SMAT enabled the prediction of the V[Combining Dot Above]O2max (ml·kg·min) from the maximal velocity (m·s) and the SSI (skating strides·kg) using the following regression equation: V[Combining Dot Above]O2max = (14.94 × maximal velocity) + (3.68 × SSI) - 24.98 (r = 0.95, SEE = 1.92). This research allowed for the update of the oxygen uptake values of the SMAT and proposed a simple measure of skating efficiency for a more accurate evaluation of V[Combining Dot Above]O2max in elite youth hockey players. By comparing the highest and lowest observed SSI scores in our sample, it was noted that the V[Combining Dot Above]O2 values can vary by up to 5 ml·kg·min. Our results suggest that skating economy should be included in the prediction of V[Combining Dot Above]O2max to improve prediction accuracy.

The aim of this study was to investigate the size of the change and asymmetry in fatigability of gluteus maximus muscles during endurance training in short-track. The research has taken into account the position of athletes during skating and the problem of fatigue and pain in these muscles. The research covered involved eight female athletes of the Polish National Team in short track, which had been prepared to the Olympic Games in PyeongChang. The surface electromyography (sEMG) system was used to measure fatigue of right and left gluteus maximus muscles, in the modified Biering-Sorensen test. The test was conducted five times during the training: before training, after warmup, and after each of 3 series of the endurance training. Comparing the mean frequency of the surface electromyography power spectrum of the test, statistically significant reduction of the average frequency value of the right muscle from 55.61 ± 7.08 to 48.64 ± 4.48 Hz and left muscle from 58.78 ± 4.98 to 53.18 ± 4.62 Hz was reported, which prove the muscle fatigue. In subsequent series tests, the sEMG signal frequency of begin decrease more than the end of the each measurement, which determines the fatigue threshold. The size of the d Cohen effect in fatigue drops along with subsequent five tests during the training. Skaters has higher frequency reduction of the right lower limb, which indicates its greater fatigue during skateing. The fatigue and asymmetry in muscle observed in short-track has implications for training and performance.

Speed skating is a technical endurance sport. Still, little is known about technical changes in junior speed skaters. Therefore, changes in technique throughout a 1500-m time-trial of elite junior speed skaters is investigated to explore differences between sexes, performance levels and competitive seasons. At (inter)national 1500-m competitions, knee and push-off angles were obtained for 120 elite junior speed skaters (56 female, 64 male, age 17.6±1.1 years) per lap at 250m (lap 1), 650m (lap 2), 1050m (lap 3) and 1450m (lap 4). Additionally, 1500m end-times and lap-times were obtained to divide skaters in faster and slower performance groups and to analyze pacing behavior. Fifteen skaters (8 female, 7 male, age 17.3±1.5 years) were measured again after 1.6±0.6 years. (Repeated measures) ANOVAs were used for statistical analyses (p<0.05). ICC, determined in a pilot study, was 0.55 for knee and 0.76 for push-off angles. Elite junior speed skaters increased their knee angles throughout the race (p<0.005), regardless of sex (p = 0.110) or performance level (p = 0.714). Push-off angles increased from lap 1-3 (p<0.001), in which men showed a larger decay than female skaters (p<0.05), this holds for both performance groups (p = 0.103). Faster skaters had smaller knee and push-off angles than slower skaters (p<0.05). Males showed smaller body angles than females (p<0.001). Faster male and female skaters showed a relative slower start and faster lap 3 compared to slower skaters (p<0.05). Development over competitive seasons showed a shift towards smaller push-off angles (p = 0.038) and less decay in knee angles from lap 2-3 (p = 0.026). The present study shows that technique throughout the 1500m deteriorates. Deterioration in technique is regardless of performance level, even with different pacing behaviors. Differences between sexes were found for push-off angles. The longitudinal development suggests changes in technique towards senior level and highlights the importance of studying juniors separate from seniors., Competing Interests: The authors have declared that no competing interests exist.

Purpose: This study aimed to assess the validity of the first (EMGth1) and second (EMGth2) breakpoints in the EMG signal during skating., Scope: Ten well-trained long track speed skaters performed a maximal incremental skating test on a slide board. EMG signals from six lower limb muscles were recorded during the last 15 s of each stage and converted to Root Mean Square for determination EMGth1 and EMGth2 using mathematical (2 and 3 linear regressions) and visual methods., Conclusions: EMGth1 had a low detection rate (<50%) while EMGth2 could be identified visually in > 80% of cases, in 85% of cases using 2-lines and 63% using 3-lines regression. Quads (VL + VM) and Gluts (GM + GMd) had the highest EMGth2 detection rate for all methods (>70%). EMGth2 from Quads and Gluts detected by the 2-lines and 3-lines regression were not different than the second ventilatory threshold (VT2) (p > 0.05), while the visual method overestimated VT2 (p < 0.01). EMGth2 detected from Quads by the 2-lines regression method presented better correlation with VT2 stage (r = 0.91), lowest bias, and limit of agreement. We conclude that EMG is a valid non-invasive method to detect VT2 during skating when using a mathematical method to determine EMGth2., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Slater, LV, Vriner, M, Schuyten, K, Zapalo, P, and Hart, JM. Sex differences in Y-balance performance in elite figure skaters. J Strength Cond Res 34(5): 1416-1421, 2020-Asymmetrical dynamic balance compared with normative populations have been associated with increased risk of injury in athletes; however, it is unclear if the current data are similar to balance performance in figure skaters. Therefore, the purpose of this study was to compare performance on the Y-balance test between sexes and disciplines in elite figure skaters. Thirty-two senior level figure skaters from 3 different disciplines (singles, dance, and pairs) completed the Y-balance test on the take-off and landing leg. Absolute differences between limbs (cm), normalized differences between limbs (% leg length), and composite scores (CSs; % leg length) were calculated for all skaters. A multivariate analysis of variance was used to identify differences in performance based on discipline and sex. Females had a greater absolute difference between limbs (mean difference = -3.62 cm) and a greater normalized difference between limbs on the posterolateral (PL) reach compared with males (mean difference = -4.26% leg length). Ice dancers had larger CSs on the take-off leg compared with pair skaters (mean difference = 6.42%). These results suggest that male and female figure skaters demonstrate differences in dynamic balance in the PL direction, with female skaters exhibiting decreased reach on the landing leg, which may suggest asymmetrical hip strength in female figure skaters and increase risk of lower extremity injury in the landing leg. Sport performance professionals should consider these sex differences when designing strength programs for elite figure skaters.

Purpose: This study aimed to analyze the development of pacing behavior of athletes during adolescence using a longitudinal design., Methods: Lap times of male short-track speed skaters (140 skaters, 573 race performances) over two or more 1500-m races during Junior World Championships between 2010 and 2018 were analyzed. Races were divided into four sections (laps 1-3, 4-7, 8-11, and 12-14). Using MLwiN (P < 0.05), multilevel prediction models in which repeated measures (level 1) were nested within individual athletes (level 2) were used to analyze the effect of age (15-20 yr), race type (fast, slow), and stage of competition (final, nonfinal) on absolute section times and relative section times (percentage of total time spent in a section)., Results: Between the ages of 15 and 20 yr, total race time decreased (-6.99 s) and skaters reached lower absolute section time in laps 8-11 (-2.33 s) and 12-14 (-3.28 s). The relative section times of laps 1-3 (1.42%) and 4-7 (0.66%) increased and of laps 8-11 (-0.53%) and 12-14 (-1.54%) decreased with age. Fast races were more evenly paced compared with slow races, with slow races having a predominantly slow first half and fast finish. Athletes in finals were faster (2.29 s), specifically in laps 4-7 (0.85 s) and laps 8-11 (0.84 s)., Conclusion: Throughout adolescence, short-track speed skaters develop more conservative pacing behavior, reserving energy during the start of the race in order to achieve a higher velocity in the final section of the race and a decrease in total race time. Coaches should take into consideration that the pacing behavior of young athletes develops during adolescence, prepare athletes for the differences in velocity distribution between race types, and inform them on how to best distribute their efforts over the different stages of competition.

Speed skating is a cyclic sport which involves the hip abductor muscles, impelling the participant forwards, and adductor muscles, in the recovery phase and decelerating the abduction movement eccentrically. This paper has the objective of describing and comparing the abduction/adduction torque-angle curves of speed skating athletes (N=10) with a group of non-practitioners young participants (N=10). Both groups presented similar peak torques and electromyography patterns for tensor fascia lata, gluteus medius, long adductor and adductor magnus. However, athletes showed higher torque-angle curve integral and abduction and adduction peak torques at different hip angles than the control group. These findings suggest an adaptation of their musculotendon actuators and a better capacity to generate mechanical work and power during a propulsion-recovery cycle., Competing Interests: The authors declare that they have no conflict of interest., (© © Georg Thieme Verlag KG Stuttgart · New York.)

Background: Data about injuries among synchronized skating athletes are lacking while physical demands in this sport discipline continue to grow. No injury data among junior synchronized skaters exist. The purpose of this study was to investigate the frequency and pattern of injuries in junior and senior synchronized skaters., Methods: In this descriptive epidemiology study anonymous questionnaires were distributed to synchronized junior and senior skaters. 708 synchronized skaters (393 juniors and 315 seniors) completed the questionnaire. Male skaters were excluded from analysis., Results: Spinal conditions were reported by 148 (37.7%) juniors compared to 149 (47.3%) of senior skaters with statistically significant cumulative incidence (P=0.01); 23% of juniors and 30.2% of senior skaters reported problems with more than one spinal region; 64.4% juniors and 72.1% senior skaters reported at least one non-spinal injury during their synchronized skating career. There were 380 unique injuries reported by junior skaters and 363 by senior skaters. Lower extremity injuries were the most common injuries in both groups of skaters, followed by upper extremity, head and trunk injuries. From all the anatomical regions mentioned, there was only statistically significant difference between the groups in the occurrence of head injuries with senior skaters having 1.9 greater odds ratio to have head injury., Conclusions: This study presents new data on the current injury pattern seen in synchronized skating since the inclusion of new skills. The number of head injuries and spinal conditions show statistically significant cumulative incidence in senior compared to junior skaters.

Douglas, AS and Kennedy, CR. Tracking in-match movement demands using local positioning system in world-class men's ice hockey. J Strength Cond Res 34(3): 639-646, 2020-While the global positioning system has been used in field sports for a decade, local positioning systems are newly available in indoor sports for the tracking of velocity and distance during competition. World-class male ice hockey players (n = 20) were monitored during 5 international matches. Speed and distance outputs were analyzed to determine the differences between positions, periods, and in-shift demands. Defense had a difference between forwards at distances covered at very slow (p < 0.001), slow (p < 0.001), and moderate (p < 0.001) speed. Forwards were found to cover a greater distance at very fast speed (p = 0.001) and sprint speed (p < 0.001). Defense had a decrease in skating distance at very fast (p < 0.001) and sprint skating speeds (p = 0.02). Forwards had an increase in very slow skating (p = 0.02) and a decrease in sprint skating distance (p = 0.02). Game situational differences were found for defense and forwards in average speeds for defense (p < 0.001) and forwards (p < 0.001). Local positioning systems data have the potential to accurately inform coaches of the position-specific demands of game situations and the training needs by position. Specifically, forwards performed more high-intensity skating than defensemen, whereas powerplay and penalty kill situations offered specific demands for the 2 positional groups. Finally, the intensity of skating was reduced in the third period for both defensemen and forwards. Further research can evaluate whether this is related to tactical decisions, or the metabolic cost of ice hockey.

Objective: To examine the therapeutic effects of the lateral push-off skater exercise vs conventional treadmill training on health-related quality of life, cardiorespiratory fitness (CRF), and balance., Design: Single-blinded, randomized controlled trial., Setting: Outpatient clinic at a tertiary hospital., Participants: Patients after minor stroke (N=36) with National Institutes of Health Stroke Scale scores≤3 between 20 and 65 years of age were randomly assigned to the intervention group (n=18) or the control group (n=18)., Interventions: Thirty-minute sessions of the skater exercise were performed 3 times weekly for 12 weeks in the intervention group. Conventional treadmill aerobic exercise was conducted in the control group at the same frequency and duration as the experimental group exercise., Main Outcome Measures: The primary outcome was measured using the European Quality of Life-5 Dimension (EQ-5D). Secondary outcomes included CRF and balance indicators. Assessments were performed at baseline (T0), 12 weeks from T0 (T1), and 16 weeks from T0 (T2)., Results: Significant improvements in EQ-5D, peak oxygen uptake (VO 2 peak), peak oxygen pulse, peak minute ventilation (VE), Dynamic Gait Index (DGI), and Berg Balance Scale (BBS) were found in the intervention group after performing the skater exercise (P<.05, all), and these improvements were sustained at T2 (P<.05, all). Between-group comparisons demonstrated greater improvements in EQ-5D, VO 2 peak, peak oxygen pulse, peak VE, DGI, and BBS in the intervention group than those in the control group at both T1 (P<.05, all) and T2 (P<0.05, all). Correlation analysis showed significant relationships between EQ-5D and VO 2 peak, peak VE, DGI, and BBS (P<.05, all)., Conclusions: The skater exercise improved health-related quality of life, CRF, and balance in patients after minor stroke more effectively than conventional treadmill-based aerobic exercise. We recommend the skater exercise as a high-intensity interval training program for patients after minor stroke., (Copyright © 2019 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.)

The aim of this study was to assess the physiological and neuromuscular responses at critical skating intensity on a slide board and to investigate the correlations between critical cadence (CC) and skating performances on ice. Thirteen well-trained speed skaters (age,19.8 ± 4.2 years; weight, 69.6 ± 9.06 kg) performed a maximal skating incremental test (IT) on a slide board. CC was determined from 3 to 4 trials to exhaustion lasting from 3.1 ± 0.7 to 13.9 ± 3.1 min, using linear and hyperbolic mathematical fittings. A time to exhaustion test at CC (TTE-CC) was performed. CC values (55.3 ± 5.0 ppm) were significantly higher than cadence at the respiratory compensation point (RCP) (53.5 ± 4.0 ppm). Mean duration of TTE-CC was 22.9 ± 4.8 min. Peak values of oxygen uptake, heart rate (HR), ventilation, respiratory exchange ratio (RER), and ratings of perceived exertion (RPE) during TTE-CC were significantly lower ( p < 0.05) than the peak values reached during the IT. Oxygen uptake, HR, ventilation, RER, and RPE significantly increased from 25% to 100% of TTE-CC. Muscle activity (integrated electromyography) significantly increased after 75% of TTE-CC for vastus lateralis and gluteus maximus muscles. Oxygen uptake at CC was better associated to skating performance on 500, 1000, 1500, and 5000 m than peak oxygen uptake at IT and oxygen uptake at RCP. Physiological responses indicate that critical skating intensity on slide board occurred within the heavy exercise domain where oxygen uptake increases but does not reach its maximum. Critical cadence could be used as a better indicator of performance and training prescription for long track speed skating distances.

Context: Pain in sport has been normalized to the point where athletes are expected to ignore pain and remain in the game despite the possible detrimental consequences associated with playing through pain. While rehabilitation specialists may not have an influence on an athlete's competitive nature or the culture of risk they operate in, understanding the consequences of those factors on an athlete's physical well-being is definitely in their area of responsibility., Objective: To explore the factors associated with the experiences of subelite athletes who play through pain in gymnastics, rowing, and speed skating., Design: The authors conducted semistructured interviews with subelite athletes, coaches, and rehabilitation specialists. They recruited coach participants through their provincial sport organization. Athletes of the recruited coaches who were recovering from a musculoskeletal injury and training for a major competition were then recruited. They also recruited rehabilitation specialists who were known to treat subelite athletes independently by e-mail., Setting: An observation session was conducted at the athlete's training facility. Interviews were then conducted either in a room at the university or at a preferred sound-attenuated location suggested by the participant., Participants: The authors studied 5 coaches, 4 subelite athletes, and 3 rehabilitation specialists., Interventions: The authors photographed athletes during a practice shortly before an important competition, and we interviewed all the participants after that competition. Our photographs were used during the interview to stimulate discussion., Results: The participant interviews revealed 3 main themes related to playing through pain. They are: Listening to your body, Decision making, and Who decides., Conclusion: When subelite athletes, striving to be the best in their sport continue to train with the pain of an injury, performance is affected in the short-term and long-term consequences are also possible. Our study provides some insight into the contrasting forces that athletes balance as they decide to continue or to stop.

This study performed an analysis of the push-off forces of elite-short-track speed skaters using a new designed instrumented short-track speed skate with the aim to improve short-track skating performance. Four different skating strokes were distinguished for short-track speed skaters at speed. The strokes differed in stroke time, force level in both normal and lateral directions, and the centre of pressure (COP) on the blade. Within the homogeneous group of male elite speed skaters ( N  = 6), diversity of execution of the force patterns in the four phases of skating was evident, while skating at the same velocities. The male participants ( N  = 6) with a better personal record (PR) kept the COP more to the rear of their blades while hanging into the curve ( r  = 0.82, p  < 0.05), leaving the curve ( r  = 0.86, p  < 0.05), and entering the straight ( r  = 0.76, p  < 0.10). Furthermore, the male skaters with a better PR showed a trend of a lower lateral peak force while entering the curve ( r  = 0.74, p  < 0.10). Females showed a trend towards applying higher body weight normalised lateral forces than the males, while skating at imposed lower velocities.

Sports performance benchmarks useful to select and guide future elites are limited in literature. The present study introduces a method to enable comparison between sports performance of different generations and creates performance benchmarks for the future elites in speed skating. 1500 m Season Best Times (SBT) of Dutch skaters (1043 females, 1812 males, age 13-26 years), who competed in at least six seasons between 1993 and 2013, were corrected for the prevailing world record (WR): rSBT=(SBT/WR)*100%. Regression analyses showed that the calendar year affected SBT (p<0.01), but not rSBT (p>0.05). Based on rSBT, performance groups were defined: elite (rSBT<110%), sub-elite (110%125%). Benchmarks were based on the slowest rSBT per age of the elite group. Of the total skaters performing within the elite benchmarks, the elite performance group represented <20% up to age 16 and <50% up to age 21. An out of sample group (n=299) confirmed the usability of the benchmarks. So, by correcting time-trial performance for the prevailing WR, elite performance benchmarks can be made based on multiple generations of elite skaters. The benchmarks can be used to select and guide future elite skaters from age 13-26 years.