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This scientific short report investigated how successful male coaches perceive gender differences in training characteristics and coaching practice among medal-winning endurance athletes. Ten male Norwegian coaches with a track record of coaching both female and male endurance world-class athletes (total of 269 Olympic, World and European Championship medals) participated in semi-structured interviews. Inductive thematic analysis revealed that all coaches mainly adjusted their key training and coaching principles to the individual athlete, rather than gender. A coach-driven and athlete-centered individualization process was essential to create trust, mutual understanding, and optimal training content. Potential gender/sex differences were perceived in four main themes: sport-specific competition demands, physiological, psychological and interpersonal factors (e.g., gender of the coach). In this context, all coaches described how training and coaching of female athletes differs from that of men, thus considering male athletes as the reference group and male physiology and psychology as the norm. Furthermore, societal factors such as a male-dominant sports culture and underlying gender stereotypes were suggested as amplifiers of gender differences. Accordingly, our report highlights the need for female perspectives in elite sports and invites further in-depth investigations of the identified gender/sex differences within the respective disciplines of training science, physiology, psychology and sociology. Key Words: Coaching, Endurance Training, Gender Differences, Sex Difference, Training Science

John F Moxnes,1 Øyvind Sandbakk,2 Kjell Hausken31Department for Protection, Norwegian Defence Research Establishment, Kjeller, Norway; 2Center for Elite Sports Research, Department of Neuroscience, Norwegian University of Science and Technology, Trondheim, Norway; 3Faculty of Social Sciences, University of Stavanger, Stavanger, NorwayAbstract: The current study adapts the power balance model to simulate cross-country skiing on varying terrain. We assumed that the skier’s locomotive power at a self-chosen pace is a function of speed, which is impacted by friction, incline, air drag, and mass. An elite male skier’s position along the track during ski skating was simulated and compared with his experimental data. As input values in the model, air drag and friction were estimated from the literature based on the skier's mass, snow conditions, and speed. We regard the fit as good, since the difference in racing time between simulations and measurements was 2 seconds of the 815 seconds racing time, with acceptable fit both in uphill and downhill terrain. Using this model, we estimated the influence of changes in various factors such as air drag, friction, and body mass on performance. In conclusion, the power balance model with locomotive power as a function of speed was found to be a valid tool for analyzing performance in cross-country skiing.Keywords: air drag, efficiency, friction coefficient, speed, locomotive power

John F Moxnes,1 Øyvind Sandbakk,2 Kjell Hausken31Department for Protection, Norwegian Defence Research Establishment, Kjeller, Norway; 2Human Movement Science Program, Norwegian University of Science and Technology, Trondheim, Norway; 3Faculty of Social Sciences, University of Stavanger, Stavanger, NorwayAbstract: The current study simulated cross-country skiing on varying terrain by using a power balance model. By applying the hypothetical inductive deductive method, we compared the simulated position along the track with actual skiing on snow, and calculated the theoretical effect of friction and air drag on skiing performance. As input values in the model, air drag and friction were estimated from the literature, whereas the model included relationships between heart rate, metabolic rate, and work rate based on the treadmill roller-ski testing of an elite cross-country skier. We verified this procedure by testing four models of metabolic rate against experimental data on the treadmill. The experimental data corresponded well with the simulations, with the best fit when work rate was increased on uphill and decreased on downhill terrain. The simulations predicted that skiing time increases by 3%–4% when either friction or air drag increases by 10%. In conclusion, the power balance model was found to be a useful tool for predicting how various factors influence racing performance in cross-country skiing.Keywords: skiing, power balance, metabolic rate, work rate, air drag, friction coefficient

In cross-country ski skating, both the G2 and G4 sub-techniques involve one pole push for every second ski push but are used at largely different speed-slope ranges. The aim of this study was to compare temporal and kinematic patterns between G2 and G4 at both identical and different speed-slope conditions. A mixed model was used to analyse spatio-temporal parameters, while a combination of dynamic time warping and statistical parametric mapping was used to compare time traces. Main spatio-temporal parameters, such as cycle time, ski contact time and swing time, differed between G2 and G4 (all p < 0.01). Moreover, two forward and more pronounced acceleration phases of the centre of mass (CoM) were visible in G4 while only one acceleration phase was present in G2. The more continuous propulsion in G2 allows for maintaining a more constant speed at steep slopes and low speeds where this sub-technique is preferred. In contrast, the achievement of high speeds while skiing on flatter terrain seem to require more dynamic motion with shorter, more explosive propulsion periods allowed for in G4. In conclusion, G2 and G4 are two unique movements as characterised by fundamentally different CoM motion and should be denoted as two different sub-techniques. [ABSTRACT FROM AUTHOR]

Abstract The interaction of acute exercise and the central nervous system evokes increasing interest in interdisciplinary research fields of neuroscience. Novel approaches allow to monitor large-scale brain networks from mobile electroencephalography (EEG) applying graph theory, but it is yet uncertain whether brain graphs extracted after exercise are reliable. We therefore aimed to investigate brain graph reliability extracted from resting state EEG data before and after submaximal exercise twice within one week in male participants. To obtain graph measures, we extracted global small-world-index (SWI), clustering coefficient (CC) and characteristic path length (PL) based on weighted phase leg index (wPLI) and spectral coherence (Coh) calculation. For reliability analysis, Intraclass-Correlation-Coefficient (ICC) and Coefficient of Variation (CoV) were computed for graph measures before (REST) and after POST) exercise. Overall results revealed poor to excellent measures at PRE and good to excellent ICCs at POST in the theta, alpha-1 and alpha-2, beta-1 and beta-2 frequency band. Based on bootstrap-analysis, a positive effect of exercise on reliability of wPLI based measures was observed, while exercise induced a negative effect on reliability of Coh-based graph measures. Findings indicate that brain graphs are a reliable tool to analyze brain networks in exercise contexts, which might be related to the neuroregulating effect of exercise inducing functional connections within the connectome. Relative and absolute reliability demonstrated good to excellent reliability after exercise. Chosen graph measures may not only allow analysis of acute, but also longitudinal studies in exercise-scientific contexts.

The purpose of this study was to compare the effect of two different methods of organizing endurance training in elite cross-country skiers approaching the competition period. During the 5-week intervention period, one group performed block periodization ( BP; n = 10) with 5 and 3 high-intensity sessions ( HIT) during the first and third training week. One HIT was performed during the remaining weeks in BP, while the group performing traditional training organization ( TRAD, n = 9) performed two weekly HIT except during the third week where they performed three HIT. HIT were interspersed with low-intensity training ( LIT) and both groups performed similar total amount of both HIT and LIT during the intervention. BP achieved a larger relative increase in peak power output and power output at a blood lactate concentration of 4 mmol/L than TRAD (4 ± 4 vs −3 ± 6% and 11 ± 10 vs 2 ± 4%, respectively, both P < 0.01). BP also increased maximal oxygen uptake by 2 ± 2% ( P < 0.05), while no changes occurred in TRAD. The effect sizes of the relative improvement in these measurements revealed moderate effects of BP vs TRAD training. The present study suggests that block periodization of endurance training have superior effects on several endurance and performance indices compared with traditional organization. [ABSTRACT FROM AUTHOR]

Three dominant techniques are used for downhill turning in cross-country skiing. In this study, kinematic, kinetic, and temporal characteristics of these techniques are described and related to skier strength and power. Twelve elite female cross-country skiers performed six consecutive turns of standardized geometry while being monitored by a Global Navigation Satellite System. Overall time was used as an indicator of performance. Skiing and turning parameters were determined from skier trajectories; the proportional use of each technique was determined from video analysis. Leg strength and power were determined by isometric squats and countermovement jumps on a force plate. Snow plowing, parallel skidding, and step turning were utilized for all turns. Faster skiers employed less snow plowing and more step turning, more rapid deceleration and earlier initiation of step turning at higher speed ( r = 0.80-0.93; all P < 0.01). Better performance was significantly correlated to higher mean speed and shorter trajectory ( r = 0.99/0.65; both P < 0.05) and to countermovement jump characteristics of peak force, time to peak force, and rate of force development ( r = −0.71/0.78/−0.83; all P < 0.05). In conclusion, faster skiers used step turning to a greater extent and exhibited higher maximal leg power, which enabled them to combine high speeds with shorter trajectories during turns. [ABSTRACT FROM AUTHOR]

This investigation was designed to analyse the kinematics and kinetics of cross-country skiing at different velocities with the herringbone technique on a steep incline. Eleven elite male cross-country skiers performed this technique at maximal, high, and moderate velocities on a snow-covered 15° incline. They positioned their skis laterally (25 to 30°) with a slight inside tilt and planted their poles laterally (8 to 12°) with most leg thrust force exerted on the inside forefoot. Although 77% of the total propulsive force was generated by the legs, the ratio between propulsive and total force was approximately fourfold higher for the poles. The cycle rate increased with velocity (1.20 to 1.60 Hz), whereas the cycle length increased from moderate up to high velocity, but then remained the same at maximal velocity (2.0 to 2.3 m). In conclusion, with the herringbone technique, the skis were angled laterally without gliding, with the forces distributed mainly on the inside forefoot to enable grip for propulsion. The skiers utilized high cycle rates with major propulsion by the legs, highlighting the importance of high peak and rapid generation of leg forces. [ABSTRACT FROM AUTHOR]

Greater gender differences have been found in exercise modes where the upper body is involved. Therefore, the present study investigated the influence of poling on gender differences in endurance performance by elite cross-country skiers. Initially, the performance of eight male and eight female sprint skiers was compared during four different types of exercise involving different degrees of poling: double poling ( DP), G3 skating, and diagonal stride ( DIA) techniques during treadmill roller skiing, and treadmill running ( RUN). Thereafter, DP was examined for physiological and kinematic parameters. The relative gender differences associated with the DP, G3, DIA and RUN performances were approximately 20%, 17%, 14%, and 12%, respectively. Thus, the type of exercise exerted an overall effect on the relative gender differences ( P < 0.05). In connection with DP, the men achieved 63%, 16%, and 8% higher VO2peak than the women in absolute terms and with normalization for total and fat-free body mass (all P < 0.05). The DP VO2peak in percentage of VO2max in RUN was higher in men ( P < 0.05). The gender difference in DP peak cycle length was 23% ( P < 0.05). In conclusion, the present investigation demonstrates that the gender difference in performance by elite sprint skiers is enhanced when the contribution from poling increases. [ABSTRACT FROM AUTHOR]

The purpose of the present study was to examine the effect of frequency on efficiency and performance during G3 roller ski skating. Eight well-trained male cross-country skiers performed three submaximal 5-min speeds (10, 13, and 16 km/h) and a time-to-exhaustion ( TTE) performance (at 20 km/h) using the G3 skating technique using freely chosen, high, and low frequency at all four speeds. All tests were done using roller skis on a large treadmill at 5% incline. Gross efficiency ( GE) was calculated as power divided by metabolic rate. Power was calculated as the sum of power against frictional forces and power against gravity. Metabolic rate was calculated from oxygen consumption and blood lactate concentration. Freely chosen frequency increased from 60 to 70 strokes/min as speed increased from 10 to 20 km/h. GE increased with power. At high power (20 km/h performance test), both efficiency and performance were significantly reduced by high frequency. In regard to choice of frequency during G3 roller ski skating, cross-country skiers seems to be self-optimized both in relation to energy saving (efficiency) and performance ( TTE). [ABSTRACT FROM AUTHOR]

This study looks at how emotions were associated with ski jumping competitions in world cup for four athletes representing the Norwegian national team in Nordic combined. The athletes documented their emotional experiences during competition rounds (trial-, and competition rounds) and non-competitive episodes (the period just after the competition round). The results in this study show that there is no clear relationship between emotions and performance between- and within the different episodes among the athletes. However, both hedonic emotions and eudaimonic emotions were experienced at high levels across all the measured episodes. Eudaimonic emotions were significantly higher during competing episodes (trial- and competition round) compared with non-competing episodes. Anger and sadness were higher after both trial jumps and competing jumps, whereas the opposite pattern was found for fear: more fear was experienced during jumps than after jumps. The results are discussed in regard of applied implications and possible future research. [ABSTRACT FROM AUTHOR]

This article looks at how emotions are associated with performance during cross-country skiing competitions among 10 senior Norwegian national level athletes. The results in this study show that there is a relatively similar emotional distribution pattern found among the athletes who are most satisfied with their performance compared to the less satisfied ones. However, the intensity in their emotions is different. The most satisfied athletes have higher intensity in their eudaimonic and hedonic emotions, while the negative emotions "sad" and "scared" are higher among the less satisfied athletes. The emotion "angry" is not significantly different between the two groups of athletes, and significantly higher in intensity compared to "sad" and "scared". The emotions in this study explain 53 % of the variance in subjective performance. The results are discussed in regard of applied implications and possible future research. [ABSTRACT FROM AUTHOR]

This article looks at how psychological variables such as passion, perceived performance, affect, worries and working alliance are associated with athlete burnout and illness and injuries among junior athletes in sport. A sample of 356 junior elite athletes from different sports such as cross country skiing, biathlon, Nordic combined, shooting, ice-hockey, ice-skating, ski jumping, alpine skiing, cycling, track and field, football, orienteering, handball, football and volleyball participated in the investigation. Our results show that harmonic passion, perceived performance, positive and negative affect, worry and working alliance are uniquely associated with athlete burnout, whereas sex, perceived performance and working alliance uniquely are associated with illness and injuries. The results are discussed in regard of applied implications and possible future research. [ABSTRACT FROM AUTHOR]

Background: Our scientific understanding of the mechanistic and practical connections between training session prescriptions, their execution by athletes, and adaptations over time in elite endurance sports remains limited. These connections are fundamental to the art and science of coaching., Objective: By using successful Norwegian endurance coaches as key informants, the aim of this study is to describe and compare best practice session models across different exercise intensities in Olympic endurance sports., Methods: Data collection was based on a four-step pragmatic qualitative study design, involving questionnaires, training logs from successful athletes, and in-depth and semi-structured interviews, followed by negotiation among researchers and coaches to assure our interpretations. Twelve successful and experienced male Norwegian coaches from biathlon, cross-country skiing, long-distance running, road cycling, rowing, speed skating, swimming, and triathlon were chosen as key informants. They had been responsible for the training of world-class endurance athletes who altogether have won > 370 medals in international championships., Results: The duration of low-intensity training (LIT) sessions ranges from 30 min to 7 h across sports, mainly due to modality-specific constraints and load tolerance considerations. Cross-training accounts for a considerable part of LIT sessions in several sports. Moderate (MIT)- and high-intensity training (HIT) sessions are mainly conducted as intervals in specific modalities, but competitions also account for a large proportion of annual HIT in most sports. Interval sessions are characterized by a high accumulated volume, a progressive increase in intensity throughout the session, and a controlled, rather than exhaustive, execution approach. A clear trend towards shorter intervals and lower work: rest ratio with increasing intensity was observed. Overall, the analyzed sports implement considerably more MIT than HIT sessions across the annual cycle., Conclusions: This study provides novel insights on quantitative and qualitative aspects of training session models across intensities employed by successful athletes in Olympic endurance sports. The interval training sessions revealed in this study are generally more voluminous, more controlled, and less exhaustive than most previous recommendations outlined in research literature., Competing Interests: Declarations Funding Open access funding provided by Kristiania University College. Competing Interests The authors declare that they have no conflicts of interest relevant to the content of this article. Availability of Data and Materials All data and materials support the published claims and comply with field standards. To protect the anonymity of the key informants, as well as their athletes, the transcribed interviews cannot be made publicly available. Ethics Approval The study followed the institutional requirements and was pre-approved by the Norwegian Centre for Research Data (reference #605672). Consent to Participate Prior to the study, the coaches provided a written informed consent to participate. Consent for Publication All respondents approved the submitted version of the manuscript for publication. Code Availability Not applicable. Author Contributions All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Espen Tønnessen and Øyvind Sandbakk. The first draft of the manuscript was written by Thomas Haugen and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript. As the authors of this study, we assert that our background provides a high level of expertise and experience in both scientific research and coaching practice arenas, enhancing the qualitative interpretation of these data. Our experience spans over 30 years, during which we have closely collaborated with world-class endurance coaches and athletes, both within the Norwegian Olympic Federation (Olympiatoppen) and various national sports federations. This hands-on involvement includes conducting training analyses alongside coaches, actively participating in training camps, and closely observing the day-to-day practices of top athletes. Additionally, many of us were involved in the development of Olympiatoppen's training diary, intensity scale, and test protocols – all crucial tools in athlete performance tracking. Moreover, we have published more than 150 articles in the field of endurance sports, demonstrating our in-depth understanding of the subject. We contend that this experience uniquely qualifies us to collect and interpret the data presented here., (© 2024. The Author(s).)

Research on world-class athletes in endurance events, such as cycling Grand Tours, has reported extreme levels of total energy expenditure. However, it has been argued that over extended periods, such as months, sustained energy expenditure is capped at approximately 2.5 times the basal metabolic rate. Triathlon is particularly notable for its high energetic demands due to its multimodal nature, requiring athletes to maintain high training volumes. In this case study, we analyzed the total energy expenditure of world-class triathlete Kristian Blummenfelt using doubly labelled water over two specific periods, along with three years of training data. Total energy expenditure ranged from 7,019-8,506 kcal/day. Reported energy intake ranged from 4,899 to 6,360 kcal/day. The annual training volumes for the years 2020-2022 were 1,480, 1,350 and 1,308 hours, respectively, following a pyramidal intensity distribution. Approximately 53% of the entire three-year period matched with the doubly labeled water measurement periods in terms of training volume, indicating that the recorded total energy expenditure is representative of the majority of the observed data. Hence, the greater part of the three-year period likely exceeds the proposed metabolic ceiling for sustained total energy expenditure. This not only questions the validity of the current metabolic limits but also suggests a new perspective on what is physiologically achievable in world-class athletes.

Purpose: To investigate the influence of menstrual-cycle (MC) phase on objective sleep and perceived recovery following high- (HIT) and low-intensity training (LIT) in endurance-trained women., Methods: Fifteen naturally menstruating, endurance-trained women completed standardized HIT and LIT sessions during the early follicular phase (EFP), ovulatory phase (OP), and midluteal phase (MLP) of 2 MCs. Overnight sleep was monitored using a Somnofy sleep monitor after each training session, and perceived recovery was assessed after 24 hours using self-report scales. MC phases were determined using the 3-step method, and noneumenorrheic MCs were retrospectively excluded from analysis., Results: MC phase had a main effect on wake after sleep onset (P ≤ .001), with higher values in MLP (33 [22] min) than EFP (22 [19] min, P = .043) and OP (14 [9] min, P = .001), sleep efficiency (P = .033), with lower values in MLP (87% [6%]) than OP (90% [8%], P = .047), and light sleep (P = .023) with higher values in MLP (59% [6%]) than EFP (54% [7%], P = .037). Session type had a main effect on perceived recovery (P < .018) and perceived muscle soreness (P = .007), indicating lower perceived recovery and higher perceived muscle soreness following HIT compared to LIT (P < .001, P = .018, respectively). No interactions were found between MC phase and session type for any of the measured variables., Conclusions: Objective sleep quality, but not perceived recovery, was influenced by MC phase, as indicated by small impairments to multiple indices of objective sleep during MLP. There were no interactions between MC phase and session type, indicating that the effect of MC on sleep and recovery is consistent regardless of session type.

Background: Perceived stress from schoolwork and perceived teacher care are shown to influence adolescents' life satisfaction. However, there is a need to further explore how levels of perceived school stress affect life satisfaction of Norwegian adolescents across gender and school levels using nationwide data, and whether this association is moderated by perceived teacher care. Hence, this paper sought to: (1) describe perceived school stress, perceived teacher care and satisfaction with life in Norwegian adolescents stratified by gender and school level, (2) examine the association between perceived school stress and satisfaction with life by testing perceived teacher care as a possible moderator and (3) explore the association between perceived teacher care and adolescents' satisfaction with life., Methods: We utilized cross-sectional data from the Norwegian Ungdata Survey from 2021, encompassing adolescents from lower and upper secondary school. Two-thirds of all Norwegian adolescents participated in the Ungdata Survey from 2021. All data is anonymous. The study variables are presented according to lower and upper secondary school as well as gender. Linear regressions were conducted and adjusted for socioeconomic status (SES) by using SPSS., Results: In total, 139,841 adolescents were included. Girls exhibited higher perceived school stress, lower perceived teacher care, and lower life satisfaction than boys in both lower and secondary school (all p < 0.01). Strong inverse associations on satisfaction with life were found in both genders in lower and upper secondary school among those who reported very frequent perceived school stress, with perceived teacher care moderating the relationship (B= -0.67; 95% CI [-0.70 to -0.65], P < 0.01]). Moreover, robust associations were unveiled between high and low levels of perceived teacher care and life satisfaction across gender and school level., Conclusions: Higher perceived school stress was strongly inversely associated with life satisfaction in Norwegian adolescents, in both girls and boys, and in both lower and secondary school. Teacher care was identified as a moderator and seems to play a crucial part in the everyday life of Norwegian adolescents. These implications extend to teacher education, practice, and policy, which should be aware of the pivotal role of perceived teacher care on Norwegian school-based adolescents' life satisfaction., (© 2024. The Author(s).)