Search Results (29)

This study investigated the influence of aerobic capacity on lactate clearance rate and heart rate recovery during ice hockey matches. Considering the growing intensity and anaerobic demands of modern ice hockey, the ability to recover quickly between high-intensity shifts is essential for optimal performance. Thirty-eight amateur ice hockey players (age: 35 ± 5 years; VO₂max: 48.93 ± 3.88 mL·min⁻¹·kg⁻¹) from the Silesian Amateur Hockey League underwent laboratory ramp tests to determine VO₂max, followed by on-ice repeated sprint tests and heart rate monitoring during matches. The results demonstrated significant positive correlations between VO₂max and lactate clearance (ΔLa4–8min [mmol/L]= 2.55 ± 0.58 mmol·L⁻¹; rho = 0.545; p < 0.001), as well as heart rate recovery (Δ%HRmax = 25.88 ± 2.09%; rho = 0.682; p < 0.001). Players with higher VO₂max exhibited a faster reduction in heart rate during recovery periods between shifts and maintained better sprint performance (rho = –0.877; p < 0.001). These findings confirm that higher aerobic capacity enhances both metabolic and autonomic recovery processes, enabling players to sustain high-intensity efforts more effectively during the game. The study highlights the importance of developing aerobic fitness in hockey training to improve recovery efficiency and match performance. Full article

Female university ice hockey players experience elevated and sustained cardiovascular stress during training and competition. There remains limited research on the “exercise dose–response” in female ice hockey players. The purpose of this study was to examine daily and weekly changes in cardiac autonomic activity across a competitive season, and to examine its association with accumulated exercise stress. Twenty-one female ice hockey players wore chest strap heart rate monitors to quantify exercise heart rate dynamics into a training load (TL) metric and time (min) performing high-intensity activity (HIA) during training and competition. Cardiac autonomic activity was expressed as both resting heart rate (RHR) and the root mean squared of successive R-R intervals (rMSSD) and was recorded immediately upon awakening each morning. The association between HRV and both TL (r = −0.420, p = 0.058) and HIA (r = −0.420, p = 0.058) was observed. The association between RHR and both TL (r = 0.109, p = 0.638) and HIA (r = 0.150, p = 0.516) was observed. rMSSD fell below the typical error for ~50% of games. In conclusion, HRV demonstrated greater sensitivity to exercise stress than RHR for quantifying the dose–response to on-ice exercise stress. Full article

Background/Objectives: As short-track speed skaters have to race multiple races to achieve success during competition, optimizing the recovery between efforts is a noteworthy performance determinant. Therefore, we compared three different recovery modalities (active cycling recovery, pneumatic compression boots, and isocapnic breathing protocol) in the context of perceived subjective pain and recovery variables, multiple biochemical and biomechanical indices, CMJ height and power, as well as repeated efforts on the ice track. Methods: Fifteen elite short-track speed skaters (eight males and seven females; age 18.3 ± 1.0 years, height 175.6 ± 7.5 cm, weight 73.7 ± 7.7 kg, 23.8 kg/m², VO₂max 55.5 mL·kg⁻¹·min⁻¹: ♂ 58 20 ± 3.6 mL·kg⁻¹·min⁻¹; and ♀ 53 ± 4.5 mL·kg⁻¹·min⁻¹) completed the study experiment and were included in the analyses. Repeated measures ANOVA with optional post hoc Bonferroni correction was used to assess the association magnitude of changes in variables across the recovery methods. Results: All the investigated protocols were associated with significant changes in multiple recovery indices observed within all the investigated protocols (p ≤ 0.05). However, for this sample, they resulted in analogous effects on subjective variables, hormonal response, creatine kinase, CMJ parameters, and on-ice performance (between-protocol effect: p ≥ 0.002). Changes in creatine kinase were generally higher in males than females (p = 0.05), which might suggest that optimal recovery protocols in short-track are gender-dependent. Conclusions: Since compression and active cycling remain gold standard recovery protocols, a similar response from isocapnic breathing suggests it may be a modality particularly useful in real-world settings. Full article

The purpose of this study was to examine the impact of caffeinated chewing gum on the physical performance of elite ice hockey players after a jet lag intervention. Fourteen national-level (age: 25.2 ± 5.4; height: 176.5 ± 5.3; weight: 78.1 ± 13.4) ice hockey players were tested late at night after a full day awake schedule with jet lag. A randomised, double-blind experimental design was employed in which participants either chewed caffeinated gum (CAF) containing 3 mg/kg caffeine or a caffeine-free placebo gum (PLA) for 10 min prior to undertaking a series of on-ice and off-ice tests. The off-ice tests included grip force, the counter-movement jump (CMJ), and the squat jump (SJ). The on-ice tests included a 35 m sprint, the S-Shape agility test, and the Yo-Yo intermittent recovery test (Yo-Yo IR1 test). The CMJ height (CAF: 47.2 ± 4.4; PL: 45.9 ± 3.5; p = 0.035; Cohen’s d = 0.32) and SJ height (CAF: 46.7 ± 4.1; PL: 44.9 ± 3.8; p = 0.047; Cohen’s d = 0.44) were found to be significantly higher in the CAF than in the PL trial. However, there were no significant differences (p > 0.05) in grip force, as well as in the 35 m sprint, the S-Shape agility test, and the Yo-Yo IR1 test. The present study found that, following a jet lag intervention, although the consumption of caffeinated gum resulted in an increase in vertical jump height, it had no impact on performance in the ice tests. The results of this study may help coaches and athletes consider the need for caffeine supplementation when experiencing jet lag. Full article

Respiratory muscle training (RMT) improves endurance performance, balance, and ability to repeat high-intensity exercise bouts, providing a rationale to be applied in short-track speedskating. To establish a preferable RMT method for short-track speedskating, the influence of inspiratory pressure threshold loading (IPTL) and voluntary isocapnic hyperpnoea (VIH) on cardiopulmonary indices and athletic performance was investigated. Sixteen elite short-track speedskaters completed 6 weeks of RMT based on IPTL or VIH. Wingate Anaerobic Tests (WAnTs), cardiopulmonary exercise tests (CPETs), spirometry assessments, and on-ice time trials were performed before and after RMT intervention. Repeated measures ANOVA was used to assess the differences between each method’s influence. No statistically significant (p > 0.05) differences between RMT methods were found in performance during the WAnT, CPET, or specific on-ice time trials. Spirometry measures were similar between both methods. Significant effects were found for the interaction between maximum breathing frequency during CPET (BFmax) and method (p = 0.009), as well as for the interaction between BFMax, method, and sex (p = 0.040). BFmax decreased for IPTL and increased for VIH. The interaction between method and sex revealed that BFmax increased only in males performing VIH. Our findings suggest that IPTL and VIH lead to analogous effects in the study participants, highlighting a negligible practical disparity in the impact of different RMT methods in elite short-track speedskaters. Full article

This real-life data collection aimed to expand an existing reference database regarding an extensively evaluated ice hockey-specific complex test (IHCT). One hundred and thirty-eight third-league professional ice hockey field players (mean ± SD; age: 26.4 ± 5.24 years; forwards: n = 94, defenders: n = 44) were investigated. IHCT data were collected over eight seasons from three third-league teams. The IHCT included parameters for the load (e.g., 10 m and 30 m sprint times, transition and weave agility times with and without a puck, slap and wrist shots on goal) and stress (e.g., lactate, heart rate). The only relevant (p < 0.002, η_p² ≥ 0.10) difference between forwards and defenders for performance was found for 30 m backward sprint without a puck (p < 0.001, η_p² = 0.10, d = 0.74). As expected, in this regard, defenders performed better than forwards. Significant differences were also found in 10 m backward sprint without a puck (p = 0.005), weave agility with a puck (p = 0.014), heart rate recovery minute 10 (p = 0.057), and goals after the test (p = 0.041). This study provides expanded position-specific third-league reference data for the IHCT. On this basis, coaches are able to evaluate players’ performance (forwards vs. defenders) and the effect of the training periods. Further research is necessary to extend this database to first- and second-league players in order to enhance the scope of the IHCT. Full article

Ischemic stroke is a serious neurological disease involving multiple complex physiological processes, including vascular obstruction, brain tissue ischemia, impaired energy metabolism, cell death, impaired ion pump function, and inflammatory response. In recent years, there has been significant interest in cell membrane-functionalized biomimetic nanoparticles as a novel therapeutic approach. This review comprehensively explores the mechanisms and importance of using these nanoparticles to treat acute ischemic stroke with a special emphasis on their potential for actively targeting therapies through cell membranes. We provide an overview of the pathophysiology of ischemic stroke and present advances in the study of biomimetic nanoparticles, emphasizing their potential for drug delivery and precision-targeted therapy. This paper focuses on bio-nanoparticles encapsulated in bionic cell membranes to target ischemic stroke treatment. It highlights the mechanism of action and research progress regarding different types of cell membrane-functionalized bi-onic nanoparticles such as erythrocytes, neutrophils, platelets, exosomes, macrophages, and neural stem cells in treating ischemic stroke while emphasizing their potential to improve brain tissue’s ischemic state and attenuate neurological damage and dysfunction. Through an in-depth exploration of the potential benefits provided by cell membrane-functionalized biomimetic nanoparticles to improve brain tissue’s ischemic state while reducing neurological injury and dysfunction, this study also provides comprehensive research on neural stem cells’ potential along with that of cell membrane-functionalized biomimetic nanoparticles to ameliorate neurological injury and dysfunction. However, it is undeniable that there are still some challenges and limitations in terms of biocompatibility, safety, and practical applications for clinical translation. Full article

The electrochemical sensing potential of two isostructural one-dimensional nickel(II) and cobalt(II) coordination polymers with 4,4′-bipyridine (4,4′-bpy) and 6-oxonicotinate (6-Onic), namely, {[Ni(4,4′-bpy)(H₂O)₄](6-Onic)₂×2H₂O}_n and {[Co(4,4′-bpy)(H₂O)₄](6-Onic)₂×2H₂O}_n, was investigated along with the polymers’ potential applications in the catalytic oxidation of methanol. The highly oxidative species from redox pairs Ni(II)/Ni(III) and Co(II)/Co(III) in these compounds represent catalytically active centres for oxidation of small molecules. A glassy carbon electrode (GCE) modified with a Ni polymer showed stability and reproducibility in 0.1 M NaOH, while the oxidation current inc 2reased with the increasing methanol concentration, suggesting that the Ni-polymer-modified electrode possess good sensing ability with respect to methanol. The GC electrode modified with the Co polymer is not reproducible and cannot be used for electroanalytical purposes under these experimental conditions. The GC electrode modified with the Ni polymer was successfully applied in the determination of methanol. This method showed favourable linear concentration dependence with a good sensitivity of 2.65 and 11.0 mA mM⁻¹, a wide concentration range (0.001–4 mM), and a detection limit of 0.8 μM, which indicates its excellent application potential for methanol oxidation and thus its determination. Full article

Landfast ice has undergone a dramatic decline in recent decades, imposing potential effects on ice travel for coastal populations, habitats for marine biota, and ice use for industries. The mapping of landfast ice deformation and the investigation of corresponding causes of changes are urgent tasks that can provide substantial data to support the maintenance of the stability of the Arctic ecosystem and the development of human activities on ice. This work aims to investigate the time-series deformation characteristics of landfast ice at multi-year scales and the corresponding influence factors. For the landfast ice deformation monitoring technique, we first combined the small baseline subset approach with ascending and descending Sentinel-1 images to obtain the line-of-sight deformations for two flight directions, and then we derived the 2D deformation fields comprising the vertical and horizontal directions for the corresponding periods by introducing a transform model. The vertical deformation results were mostly within the interval [−65, 23] cm, while the horizontal displacement was largely within the range of [−26, 78] cm. Moreover, the magnitude of deformation observed in 2019 was evidently greater than those in 2020 and 2021. In accordance with the available data, we speculate that the westerly wind and eastward-flowing ocean currents are the dominant reasons for the variation in the horizontal direction in Cambridge Bay, while the factors causing spatial differences in the vertical direction are the sea-level tilt and ice growth. For the interannual variation, the leading cause is the difference in sea-level tilt. These results can assist in predicting the future deformation of landfast ice and provide a reference for on-ice activities. Full article

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. Full article

Hockey skating objective assessment can help coaches detect players’ performance drop early and avoid fatigue-induced injuries. This study aimed to calculate and experimentally validate the 3D angles of lower limb joints of hockey skaters obtained by inertial measurement units and explore the effectiveness of the on-ice distinctive features measured using these wearable sensors in differentiating low- and high-calibre skaters. Twelve able-bodied individuals, six high-calibre and six low-calibre skaters, were recruited to skate forward on a synthetic ice surface. Five IMUs were placed on their dominant leg and pelvis. The 3D lower-limb joint angles were obtained by IMUs and experimentally validated against those obtained by a motion capture system with a maximum root mean square error of 5 deg. Additionally, among twelve joint angle-based distinctive features identified in other on-ice studies, only three were significantly different (p-value < 0.05) between high- and low-calibre skaters in this synthetic ice experiment. This study thus indicated that skating on synthetic ice alters the skating patterns such that the on-ice distinctive features can no longer differentiate between low- and high-calibre skating joint angles. This wearable technology has the potential to help skating coaches keep track of the players’ progress by assessing the skaters’ performance, wheresoever. Full article

Physical characteristics of elite male bandy players have not been studied for the last 30 years. Therefore, the purpose of this study was to evaluate the physical characteristics of elite male bandy players with respect to playing positions. A cross-sectional study was performed that included 25 male bandy players from one of the highest-ranked bandy leagues in the world. Body weight, length, isometric mid-thigh pull, countermovement jump, squat jump, unilateral long jump, bilateral long jump, 15- and 30-m sprint, 15-m flying sprint, and VO_2max were tested. Players were divided into forwards, midfielders, and defenders. Forwards had significantly (p = 0.012) higher relative VO_2max than defenders (59.8 ± 4.3 compared to 53.0 ± 5.6 mL/kg/min). No significant differences for any of the other measurements were observed between positions. This is the first study to present the physical characteristics between playing positions in off- and on-ice tests for male bandy players competing at the highest level. Today’s bandy players are heavier and have lower relative VO_2max compared with players in the early 1990s. However, their work capacities have increased since their absolute VO_2max is higher. These results provide benchmark values that can serve as a foundation for strength and conditioning professionals when designing future training programs. Full article

In ice hockey, the butterfly style/stance is a technique distinguished by the goalkeepers (goalie) dropping to their knees to block attempts to score. Although this goalie style has been around for many years, comparisons between on and off-ice attire has not been undertaken. Therefore, this preliminary study compared differences in torso acceleration and energy expenditure by way of the Metabolic Equivalent of Task (MET) during off-ice and on-ice butterfly stances/saves. Seven participants each performed 8 on-ice butterfly saves/stances whilst wearing full hockey attire followed by 8 off-ice butterfly stances without wearing full hockey attire whilst torso acceleration was collected. The off-ice movement significantly increased vertical torso acceleration (p < 0.01, d > 0.90) with increased MET, compared to on-ice motion. Despite no significant difference in anteroposterior and mediolateral torso kinematics, vector magnitudes were significantly greater (p < 0.01, d > 0.90) when the stance was performed off-ice. The increased vertical acceleration observed when goalies performed the movement off-ice could be due to a failure to maintain adequate posture without the support of the external load. The results of this study may help inform off-ice training interventions for ice hockey goalkeeping. Full article

In the field of ice hockey, body mass and height have always played a role in team selection. This study aims to analyze the associations between anthropometry and multiple dimensions of performance among elite adolescent ice hockey players. Methods: 187 adolescent players (males: n = 80, 13.81 years; females: n = 107, 14.96 years) took part in the study, in Camp 1. Off-ice fitness and on-ice skating tests were performed. Camp 2 consists of on-ice tests and match performance with players selected by coaching staff at Camp 1. Camp 2 data came from official matches performance and a combination of skating tests and intrasquad matches. Hockey Quebec’s selection process consists of going from an entire pool of athletes to a team of twenty-five players, through several camps spread over two years. Correlation analyses were conducted to verify associations between anthropometric measures and performances. Results: In Camp 1, heavier-taller male athletes displayed better performances in most off-ice fitness tests, while heavier female athletes tended to display poorer performance. Camp 2 showed no significant correlations in on-ice tests and match performance. However, some tendencies were observed: heavier male players were less involved in blocked shots, and taller females were more agile. Conclusions: Despite off-ice advantages, the taller-heavier prototype does not translate directly to better performance on the ice among elite adolescent players. Coaches should analyze anthropometric characteristics with caution, and place more focus on match-specific abilities to identify talent. Full article

Ice environments pose challenges for conventional underwater acoustic localization techniques due to their multipath and non-linear nature. In this paper, we compare different deep learning networks, such as Transformers, Convolutional Neural Networks (CNNs), Long Short-Term Memory (LSTM) networks, and Vision Transformers (ViTs), for passive localization and tracking of single moving, on-ice acoustic sources using two underwater acoustic vector sensors. We incorporate ordinal classification as a localization approach and compare the results with other standard methods. We conduct experiments passively recording the acoustic signature of an anthropogenic source on the ice and analyze these data. The results demonstrate that Vision Transformers are a strong contender for tracking moving acoustic sources on ice. Additionally, we show that classification as a localization technique can outperform regression for networks more suited for classification, such as the CNN and ViTs. Full article