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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

The purpose of this study was to compare the effects of 10 weeks of effort-matched short intervals ( SI; n = 9) or long intervals ( LI; n = 7) in cyclists. The high-intensity interval sessions ( HIT) were performed twice a week interspersed with low-intensity training. There were no differences between groups at pretest. There were no differences between groups in total volume of both HIT and low-intensity training. The SI group achieved a larger relative improvement in VO2max than the LI group (8.7% ± 5.0% vs 2.6% ± 5.2%), respectively, P ≤ 0.05). Mean effect size ( ES) of the relative improvement in all measured parameters, including performance measured as mean power output during 30-s all-out, 5-min all-out, and 40-min all-out tests revealed a moderate-to-large effect of SI training vs LI training ( ES range was 0.86-1.54). These results suggest that the present SI protocol induces superior training adaptations on both the high-power region and lower power region of cyclists' power profile compared with the present LI protocol. [ABSTRACT FROM AUTHOR]

The aim of the present study was to assess the reliability and validity of the Newtest Powertimer 300-series(R) portable contact mat and photocells (Newtest Oy, Finland). The participants were 20 male soccer players aged 19.1±3.5 years. The validity and reliability of the Powertimer (contact mat and photocells) were assessed in a comparison of a laboratory testing method (force platform and photocells) and the Newtest Powertimer system. All participants were tested on 40-m sprint, countermovement jump, and squat jump. The results showed that the Powertimer was a reliable instrument for both jumping and running. The system did not show any marked systematic bias (P < 0.05) and the random error associated with it was negligible. A comparison of the laboratory testing method with the Powertimer revealed that the Powertimer contact mat and photocells had poor validity and the bias in measurement differed from that of the laboratory testing method (P < 0.05). The Newtest Powertimer testing system was shown to be a useful instrument for measuring jump height and running speed. However, if a comparison of overall values of jumping height is intended, it is important to use the same testing system, because different systems give different results. It is also advisable to use this equipment only if no other 'gold standard' equipment is available. [ABSTRACT FROM AUTHOR]

Background: The Keiser 10-rep leg press test protocol employs short inter-repetition rest intervals (2-38 s), raising concerns as to whether athletes perform optimally. Objectives: The aim of this study was to compare the results of the standard Keiser protocol with an identical protocol modified to include a significantly longer inter-repetition rest intervals and to evaluate whether these effects differed between men and women. Methods: A total of 30 athletes (age 17.1 ± 0.9 years, height 177.8 ± 8.8 cm, and body mass 71.9 ± 11.3 kg) performed three separate tests (total of ~900 repetitions) in a Keiser A420 leg press machine, separated by 4 to 8 days. Test day 1 included a 1RM test followed by a 10-repetition force-velocity test with a standard rest intervals. Test days 2 and 3 involved the same test, with either standard short rest intervals or fixed 3 min inter-repetition rest intervals. Results: Increasing inter-repetition rest intervals significantly improved V 0 and P max for men and V 0 and FV slope for women. The benefits of longer rest were notably more pronounced in men, particularly at light to moderate loads, where standard Keiser rest intervals are short (2-9 s). However, extending rest intervals beyond approximately 30 s, as applied at higher loads, provided no additional advantages. Conclusions: Longer rest intervals improved force-velocity metrics more in men than women, with the effect being most pronounced at light to moderate loads where standard protocols utilize short rest intervals (2-9 s). These findings suggest that women recover faster than men under these conditions. However, extending rest beyond 30 s at higher loads provides no additional benefits and is counterproductive at maximal loads.

Purpose: To describe warning signs, monitoring tools, and training- and non-training-related actions taken by world-class endurance coaches in cases of underperformance., Methods: Twelve highly acclaimed male Norwegian coaches known for coaching world-class endurance athletes with a remarkable collection of over 350 Olympic, World, and European Championship medals-primarily with Norwegian athletes-participated in the study. Data collection and analyses followed a 3-step pragmatic qualitative study design, including an initial questionnaire, in-depth interviews, and structured negotiation between researchers and coaches., Results: Reduced performance levels and discrepancies between external (speed or power output) and internal (heart rate, lactate concentrations, and rating of perceived exertion) training-intensity measures in competitions, key training sessions, and testing scenarios, as well as observed changes in emotional state and coach-athlete communication, were highlighted as early warning signs of underperformance. Consistently, daily follow-up, systematic use of training diaries, training-intensity measures, and information from testing scenarios were rated as the most important monitoring tools in both detection and management of underperformance. In cases of underperformance, ruling out medical conditions as underlying causes was followed by a decreased training load (intensity and volume) and actions to reduce life stress to restore athletes' performance levels., Conclusions and Practical Applications: The presented data collectively propose applying both objectively and subjectively measured monitoring tools and systems to the early detection and management of underperformance in endurance athletes. In addition, this should be complemented by the holistic and observational role of the coach.

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).)

Purpose: To investigate the training and development process of a multiple-Grand-Slam finalist., Methods: A mixed-methods case-study design was used to capture the quantitative and qualitative aspects related to the training and successful development process. We used a 3-step data-collection process and pragmatic analyses of (1) training history based on logs, plans, and questionnaires; (2) in-depth semistructured interviews with the player's head coach/father, physical coach, and team administrator/mother; and (3) systematic quality assurance through negotiation among researchers and all key informants, including the player., Results: The player's exceptional performance level was achieved by a progressive, nonlinear increase in annual training load during childhood and early youth, stabilizing at 800 sessions and 1250 to 1300 hours per year at the age of 19. The annual tennis-specific training plateaued at ∼750 hours from the age of 15, and 60 to 80 matches were played in most of the analyzed years. Point-play accounted for approximately 50% of the total amount of specific tennis training, clearly ahead of ground strokes (∼30%), serve/return (∼15%), and smash/volley (∼5%). Physical-conditioning hours increased 5-fold from 12 to 19 years, before stabilizing at ∼500 hours at senior age. Key success factors included the athlete's multidimensional sports talent, discipline, and inner drive; a highly dedicated father and tennis-enthusiastic family; and strong support from a complementary and interdisciplinary performance team., Conclusion: This study provides novel information regarding the training and development process for a world-leading tennis player, providing a point of departure for the development of future talents.

Purpose: To compare designs of training sessions applied by world-class cross-country skiers during their most successful junior and senior season., Methods: Retrospective analysis of self-reported training characteristics (ie, training form, intensity, and exercise mode) among 8 male and 7 female world-class cross-country skiers was conducted., Results: Total number of sessions (441 [71] vs 519 [34], P < .001, large effect) and mean duration (1.5 [0.1] h vs 1.7 [0.1] h, P < .001, moderate effect) increased from junior to senior age. More double-session days were performed at senior age (124 [50] vs 197 [29] d, P < .001, large). The number (310 [64] vs 393 [64], P < .001, large effect) and duration (1.3 [0.1] h vs 1.5 [0.1] h, P < .001, moderate effect) of low-intensity training sessions increased from junior to senior age. Regarding intensive training, most emphasis was put on high-intensity training sessions lasting 20 to 39 minutes with <5-minute intervals at junior age, while 40 to 59 minutes of moderate-intensity training with 5- to 9-minute intervals was predominant at senior age. More MIXED (combined moderate- and high-intensity) sessions (9 [7] vs 14 [7], P = .023, moderate effect) and longer races (0.5 [0.1] h vs 0.6 [0.1] h, P = 0.29, moderate effect) compensated for fewer high-intensity training sessions at senior age (36 [17] vs 25 [10], P = .027, moderate effect). Duration of strength-training sessions increased significantly (0.6 [0.1] vs 0.8 [0.2] h, P = 0.30, moderate effect), while other training forms remained unchanged., Conclusions: World-class cross-country skiers increased their training volume from junior to senior age primarily by more and longer low-intensity training sessions and more often training twice per day. Concurrently, the most frequent intensive sessions were modified from high- to moderate-intensity training, lasted longer, and contained longer intervals.

Purpose: To compare training characteristics and aerobic power (VO 2max ) between the most successful junior and senior seasons of world-class cross-country (XC) skiers and to identify differences between sexes and among sprint and distance skiers. Methods: Retrospective analysis was conducted on self-reported training and VO 2max tests of ten male and seven female world-class XC-skiers, collectively holding 38 Olympic medals. Training was categorized by form (endurance, strength, speed, other) and mode (specific, unspecific) and was divided into low- (LIT), moderate- (MIT), and high-intensity training (HIT). Results: Total training increased by 203 ± 130 h (35% ± 31%, p < .001, large effect) and 78 ± 69 sessions (21% ± 24%, p < .001, very large effect). Junior training volume (658 ± 107 h) did not correlate with senior volume (861 ± 74 h) but correlated negatively with changes in volume ( r = -.822, p < .001). No sex differences were observed related to total volume, but distance skiers increased their total volume more than sprint skiers ( p = .037, large effect). Endurance training increased by 197 ± 117 h ( p < .001; large effect) tied to increased low-intensity training (186 ± 115 h, p < .001; large effect) and moderate-intensity training (13 ± 7 h, p < .001; large effect). Training intensity distribution (% LIT/MIT/HIT) was 91/3/6 in junior and 92/4/4 in senior season. Women demonstrated greater increase of unspecific modes (100 ± 58 vs. 37 ± 44 h, p = .022; large effect) and strength training (25 ± 23 vs. -3 ± 17 h, p = .010, large effect). Men improved absolute (8% ± 5%; p = .009; large effect) and relative VO 2max (6% ± 4%; p = .016; large effect) from junior to senior, while women only increased relative VO 2max (7% ± 5%, p = .012; large effect). Conclusion: This study provides novel information regarding changes in training characteristics and aerobic power from junior to senior age in world-class XC-skiers. Overall, the enhanced training volume during this transition was primarily driven by increased LIT and MIT and the exceptionally high relative VO 2max at junior age further increased in both sexes., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Walther, Haugen, Solli, Tønnessen and Sandbakk.)

Background: Although walking is the most common exercise modality in daily life for most humans, running and cycling are the most applied exercise modalities during maximal oxygen uptake (VO2max) testing. The aim of this study was to assess the reliability and validity of walking as exercise modality during VO2max testing., Methods: Sixteen participants (25±3 years, 172±9 cm, 69±15 kg, and VO2max 50±4 mL/kg/min) performed four incremental running- and walking VO2max tests (two tests in each condition) within 2-3 weeks. During the walking condition, the speed was set to 7 km/h, and the treadmill incline increased by 2.5% each min until exhaustion. Results from these tests were validated against a running protocol with 5.3% treadmill incline where the speed increased by 1 km/h each min until exhaustion., Results: The walking protocol achieved similar reliability values for absolute and relative VO2max when compared to the running condition. No significant differences in VO2max were observed between test session 1 and 2 for any of the tests. Significantly higher absolute VO2max (3.39±0.77 vs. 3.50±0.84 L/min; trivial difference) were observed in the running versus walking condition, while no significant differences in relative VO2max, BLa or Borg were detected. CVs for absolute and relative VO2max between the analyzed exercise modalities were ~5%., Conclusions: Although the present participants achieved 2-3% lower VO2max when the walking test protocol was applied, walking seems to be a promising exercise-modality alternative during VO2max testing in clinical settings.

Background: Elite sport is continuously evolving. World records keep falling and athletes from a longer list of countries are involved., Purpose: This commentary was designed to provide insights into present and future trends associated with world-class endurance training based on the perspectives, experience, and knowledge of an expert panel of 25 applied sport scientists., Results: The key drivers of development observed in the past 10-15 years were related to (1) more accessible scientific knowledge for coaches and athletes combined with (2) better integration of practical and scientific exchange across multidisciplinary perspectives within professionalized elite athlete support structures, as well as (3) utilization of new technological advances. Based on these perspectives, we discerned and exemplified the main trends in the practice of endurance sports into the following categories: better understanding of sport-specific demands; improved competition execution; larger, more specific, and more precise training loads; improved training quality; and a more professional and healthier lifestyle. The main areas expected to drive future improvements were associated with more extensive use of advanced technology for monitoring and prescribing training and recovery, more precise use of environmental and nutritional interventions, better understanding of athlete-equipment interactions, and greater emphasis on preventing injuries and illnesses., Conclusions: These expert insights can serve as a platform and inspiration to develop new hypotheses and ideas, encourage future collaboration between researchers and sport practitioners, and, perhaps most important, stimulate curiosity and further collaborative studies about the training, physiology, and performance of endurance athletes.

Objective: To evaluate the effectiveness of communication and coordination combined with designing a progressive and individualised sport-specific training program for reducing injury prevalence in youth female and male football and handball players transitioning to a sports academy high school. An additional aim was to investigate the characteristics of the reported injuries., Methods: Forty-two Norwegian athletes were randomised into an intervention or control group. Mean age, height, weight and BMI was 15.5 ± 0.5 years, 178.6 cm ± 6.3 cm, 71.3 ± 9.8 kg, 22.3 ± 2.7 BMI for the intervention group (IG) ( n  = 23), and 15.4 ± 0.5 years, 175.6 cm ± 6.6 cm, 67.1 ± 9.8 kg, 21.7 ± 2.4 BMI for the control group (CG) ( n  = 19). During the summer holiday, the intervention group received weekly progressive, individualised sport-specific training programs and weekly follow-up telephone calls from the researchers. All athletes completed a baseline questionnaire and a physical test battery. Training data and injuries were recorded prospectively for 22 weeks using the Oslo Sports Trauma Research Center Questionnaire on Health Problems (OSTRC-H2). A two-way chi-square ( χ 2 ) test of independence was conducted to examine the relationship between groups and injury., Results: Average weekly prevalence of all injuries was 11% (95% CI: 8%-14%) in IG and 19% (95% CI: 13%-26%) in CG. Average weekly prevalence of substantial injuries was 7% (95% CI: 3%-10%) in IG and 10% (95% CI: 6%-13%) in CG. The between-group difference in injuries was significant: χ 2 (1, N  = 375) = 4.865, p  = .031, φ  = .114, with 1.8 times higher injury risk in CG vs. IG during the first 12 weeks after enrolment., Conclusions: For student athletes transitioning to a sports academy high school, progressive individualised, sport-specific training programs reduced the prevalence of all-complaint injuries following enrolment. Clubs and schools should prioritise time and resources to implement similar interventions in periods where student athletes have less supervision, such as the summer holidays, to facilitate an optimal transition to a sports academy high school., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2023 Nyhus Hagum, Tønnessen, Hisdal and Shalfawi.)

Background: Despite its small population, Norway wins a disproportionately large number of medals in international competitions. Therefore, it has been thought that the Norwegian sports model and sports school programs are influential in developing young Norwegian athletes to achieve such results. Today, more than 110 Norwegian private and public schools offer the elite sports program in Norway. Most student athletes attending those schools combine their high school education with elite sports, where they attend training sessions at both school and clubs. The number of people involved with the student athlete on a daily basis (i.e., other student athletes, club coaches, school coaches, schoolteachers, parents, and health personnel) indicate the importance of optimal communication and coordination. However, to the authors' knowledge, no previous studies have explored communication and coordination among this population group. Therefore, the primary objective of this study was to use a holistic analysis of team dynamics using the Relational Coordination Survey as a measure to explore the relational coordination within and between student athletes, club coaches, and school coaches. A secondary objective of this study was to explore student athletes', club coaches', and school coaches' relational coordination with schoolteachers, parents, and health personnel. In addition, the study aimed to explore differences in student athletes' relational coordination with their significant others according to sport, school, performance level, sex, and school year., Methods: The quality of relational coordination was measured by a cross-sectional questionnaire of student athletes ( n = 345), club coaches ( n = 42), and school coaches ( n = 25) concerning training load and life load. Multiple one-way analyses of variance were used to assess differences between groups., Results: The results show that student athletes, club coaches, and school coaches perceived moderate to weak relational coordination with parents, schoolteachers, and health personnel. Student athletes' relational coordination score with parents was the only strong score observed. Furthermore, the results reveal notable differences in student athletes' relational coordination with the roles according to their characteristics., Conclusions: The findings suggest a potential for enhancing relationships and communication within and between the significant roles involved with student athletes. The results further indicate that those involved with the student athlete should consider a holistic approach to enhance communication and coordination, including physical, psychological, and other life factors, for optimal student athlete management and development. More resources are necessary to facilitate effective communication and coordination regarding the student athlete's total load.

Purpose: The concept of training quality reflects that the effect of training is dependent on more than the mere product of training load (eg, duration, intensity, frequency). The aims of this commentary are to (1) propose a practice-oriented framework to describe training quality and its general and context-dependent characteristics and (2) discuss how athletes and coaches can work to improve training quality., Conclusions: Training quality can be viewed from different perspectives. The holistic dimension includes the entire training process (goal setting, gap analysis, application of training principles and methods, etc), while a narrower dimension encompasses the specific training sessions and how they are executed in relation to the intended purpose. To capture the varying contexts, we define training quality as the degree of excellence related to how the training process or training sessions are executed to optimize adaptations and, thereby, improve overall performance. Although training quality is challenging to quantify, we argue that identification and assessment of quality indicators will increase our scientific understanding and consequently help coaches and athletes to improve training quality. We propose that the physical, technical, and psychological factors of training quality can be improved through an individualized learning process of systematic planning, execution, and debriefing. However, assessment tools should be identified and scientifically validated across different training sessions and sports. We encourage further interventions to improve training quality.

In this review we integrate the scientific literature and results-proven practice and outline a novel framework for understanding the training and development of elite long-distance performance. Herein, we describe how fundamental training characteristics and well-known training principles are applied. World-leading track runners (i.e., 5000 and 10,000 m) and marathon specialists participate in 9 ± 3 and 6 ± 2 (mean ± SD) annual competitions, respectively. The weekly running distance in the mid-preparation period is in the range 160-220 km for marathoners and 130-190 km for track runners. These differences are mainly explained by more running kilometers on each session for marathon runners. Both groups perform 11-14 sessions per week, and ≥ 80% of the total running volume is performed at low intensity throughout the training year. The training intensity distribution vary across mesocycles and differ between marathon and track runners, but common for both groups is that volume of race-pace running increases as the main competition approaches. The tapering process starts 7-10 days prior to the main competition. While the African runners live and train at high altitude (2000-2500 m above sea level) most of the year, most lowland athletes apply relatively long altitude camps during the preparation period. Overall, this review offers unique insights into the training characteristics of world-class distance runners by integrating scientific literature and results-proven practice, providing a point of departure for future studies related to the training and development in the Olympic long-distance events., (© 2022. The Author(s).)

This cross-sectional study examined self-reported weekly training volume and perceived training distress in Norwegian student athletes according to gender, type of sport, school program, and school year. The Norwegian version of the Multicomponent Training Distress Scale (MTDS-N) was completed by 608 student athletes (M age = 17.29 ± .94). Univariate and multivariate techniques were used in data analyses. Results revealed significant differences in weekly training volume between sport types. No significant differences in weekly training volume were found for gender, school year, or school program. However, a multivariate effect was found for gender, with females perceiving higher levels of training distress than males. A multivariate interaction effect between school year and training volume was also observed. We recommend that practitioners use a conceptual framework to periodize training and monitor training distress in student athletes, particularly in females, to preserve physiological and psychological well-being and ensure a progressive training overload leading to positive performance development., Competing Interests: The authors have declared that no competing interests exist.

Purpose: To describe the training volume, intensity distribution, and use of swimming styles during a Paralympic cycle in a multiple swimming champion with paraplegia., Methods: The female Paralympic swimmer was 23-26 years of age and had a body mass of 60 to 62 kg and a body height of 174 cm. She has a spinal cord injury at the Th6 level, competed in the S5/SB4 Para swimming classes, and uses a wheelchair for mobility. Training time, as well as distance in the different intensity zones and swimming styles, was registered with the "workouts for swim coaches" software throughout a full Paralympic cycle., Results: The Para swimmer performed a total of 388, 524, 471, and 656 annual hours of swimming, corresponding to 1126, 1504, 1463, and 1993 km, in the 2012-13, 2013-14, 2014-15, and 2015-16 seasons, respectively. In addition, she performed 1 to 3 weekly dry-land strength sessions and 4 to 6 weekly dry-land basic skill sessions. She conducted 91% to 94% of the swimming distance in each macrocycle at low intensity, 2% to 4% at moderate intensity, and 3% to 6% at high intensity. She performed 78% to 84% of the swimming distance in each macrocycle in the freestyle swimming technique and the remaining 16% to 22% in the backstroke, breaststroke, and butterfly techniques., Conclusion: This case study exemplifies how a female Paralympic swimmer with paraplegia progressed her training in the seasons leading up to the Paralympic Games, reaching an annual training distance of 2000 km, which is similar to that of able-bodied swimmers.

Despite an increasing amount of research devoted to middle-distance training (herein the 800 and 1500 m events), information regarding the training methodologies of world-class runners is limited. Therefore, the objective of this review was to integrate scientific and best practice literature and outline a novel framework for understanding the training and development of elite middle-distance performance. Herein, we describe how well-known training principles and fundamental training characteristics are applied by world-leading middle-distance coaches and athletes to meet the physiological and neuromuscular demands of 800 and 1500 m. Large diversities in physiological profiles and training emerge among middle-distance runners, justifying a categorization into types across a continuum (400-800 m types, 800 m specialists, 800-1500 m types, 1500 m specialists and 1500-5000 m types). Larger running volumes (120-170 vs. 50-120 km·week -1 during the preparation period) and higher aerobic/anaerobic training distribution (90/10 vs. 60/40% of the annual running sessions below vs. at or above anaerobic threshold) distinguish 1500- and 800-m runners. Lactate tolerance and lactate production training are regularly included interval sessions by middle-distance runners, particularly among 800-m athletes. In addition, 800-m runners perform more strength, power and plyometric training than 1500-m runners. Although the literature is biased towards men and "long-distance thinking," this review provides a point of departure for scientists and practitioners to further explore and quantify the training and development of elite 800- and 1500-m running performance and serves as a position statement for outlining current state-of-the-art middle-distance training recommendations., (© 2021. The Author(s).)

Purpose: To determine the impact of interval training frequency in elite endurance athletes. It was hypothesized that two longer sessions would elicit greater performance improvements and physiological adaptation than four shorter sessions at the same intensity., Methods: Elite cross-country skiers and biathletes were randomly assigned to either a high-frequency group (HF group) (5 M, 1 F, age 22 (19-26), VO 2max 67.8 (65.5-70.2) mL/kg/min) doing four short interval sessions per week or a low-frequency group (LF group) (8 M, 1 F, age 22 (18-23), VO 2max 70.7 (67.0-73.9) mL/kg/min) doing two longer interval sessions. All interval sessions were performed at ~85% of maximum heart rate, and groups were matched for total weekly training volume. Pre- and post-intervention, athletes completed an 8 km rollerski time-trial, maximal oxygen uptake (VO 2max ) test, and an incremental, submaximal exercise test., Results: The LF group had a statistically significant improved time-trial performance following the intervention ( p = 0.04), with no statistically significant changes in the HF group. Similarly, percentage utilization of VO 2max at anaerobic threshold ( p = 0.04) and exercise economy ( p = 0.01) were statistically significantly improved following the intervention in the LF group only. No statistically significant changes in VO 2max were observed in either group., Conclusions: Two longer interval sessions appear superior to four shorter sessions per week in promoting endurance adaptations and performance improvements in elite endurance athletes. Despite matched training volume and exercise intensity, the larger, more concentrated exercise stimulus in the LF group appears to induce more favorable adaptations. The longer time between training sessions in the LF group may also have allowed athletes to recover more effectively and better "absorb" the training. These findings are in line with the "best practice" observed by many of the world's best endurance athletes.

Purpose: To investigate the factors associated with underperformance and the subsequent changes in training characteristics and supportive actions when returning to the world's best cross-country skier., Methods: The participant is the most decorated winter Olympian, with 8 Olympic gold medals, 18 World Championship titles, and 114 World Cup victories. Training data were categorized by training form (endurance, strength, and speed); intensity (low, moderate, and high); and mode (running, cycling, and skiing/roller skiing). In addition, test data were retrospectively analyzed, and interviews were performed with the participant and her support team., Results: After the competitive season, the participant had 8 weeks without systematic training and an evaluation process aiming to detect the factors contributing to underperformance. Here physiological, technical, and psychological challenges were detected. As a consequence, the participant included less high-intensity training (1.2 vs 2.1 sessions/wk, P = .011); more moderate-intensity training (0.9 vs 0.4 sessions/wk, P = .016); and more low-intensity training (6.9 vs 5.9 sessions/wk, P = .036) during the general preparation phase but with similar total endurance training load as previous season. In addition, more strength training (1.6 vs 1.1 h/wk, P = .036) and new ski-specific strength exercises were included. Finally, the athlete's autonomy when planning and adjusting training was increased, nontraining stressors were reduced, more frequent testing was included, systematic mental training was initiated, her nutritional strategy was adjusted, and her asthma treatment was optimized., Conclusions: Overall, the current case study could be used as a framework for the holistic approach to treating an overtraining condition and for generation of new hypothesis in this exiting area.

Despite a voluminous body of research devoted to sprint training, our understanding of the training process leading to a world-class sprint performance is limited. The objective of this review is to integrate scientific and best practice literature regarding the training and development of elite sprint performance. Sprint performance is heavily dependent upon genetic traits, and the annual within-athlete performance differences are lower than the typical variation, the smallest worthwhile change, and the influence of external conditions such as wind, monitoring methodologies, etc. Still, key underlying determinants (e.g., power, technique, and sprint-specific endurance) are trainable. In this review, we describe how well-known training principles (progression, specificity, variation/periodization, and individualization) and varying training methods (e.g., sprinting/running, technical training, strength/power, plyometric training) are used in a sprint training context. Indeed, there is a considerable gap between science and best practice in how training principles and methods are applied. While the vast majority of sprint-related studies are performed on young team sport athletes and focus on brief sprints with maximal intensity and short recoveries, elite sprinters perform sprinting/running over a broad range of distances and with varying intensity and recovery periods. Within best practice, there is a stronger link between choice of training component (i.e., modality, duration, intensity, recovery, session rate) and the intended purpose of the training session compared with the "one-size-fits-all" approach in scientific literature. This review provides a point of departure for scientists and practitioners regarding the training and development of elite sprint performance and can serve as a position statement for outlining state-of-the-art sprint training recommendations and for generation of new hypotheses to be tested in future research.

In short-term studies, block periodization of high-intensity training (HIT) has been shown to be an effective strategy that enhances performance and related physiological factors. However, long-term studies and detailed investigations of macro, meso, and micro-periodization of HIT blocks in world-class endurance athletes are currently lacking. In a recent study, we showed that the world's most successful cross-country (XC) skier used two different periodization models with success throughout her career. One including extensive use of HIT blocks, namely BP, and one using a traditional method namely TRAD. In this study, we compare BP with TRAD in two comparable successful seasons and provide a detailed description of the annual use of HIT blocks in BP. The participant is the most-decorated winter Olympian, with 8 Olympic gold medals, 18 world championship titles, and 114 world cup victories. Training data was categorized by training form (endurance, strength, and speed), intensity [low (LIT), moderate (MIT), and HIT], and mode (running, cycling, and skiing/roller skiing). No significant difference was found in the total endurance training load between BP and TRAD. However, training volume in BP was lower compared to TRAD (15 ± 6 vs. 18 ± 7 h/wk, P = 0.001), mainly explained by less LIT (13 ± 5 vs. 15 ± 5 h/wk, P = 0.004). Lower volume of MIT was also performed in BP compared to TRAD (13 vs. 38 sessions/year), whereas the amount of HIT was higher in BP (157 vs. 77 sessions/year). While BP included high amounts of HIT already from the first preparation period, followed by a reduction toward the competition period, TRAD had a progressive increase in HIT toward the competition period. In BP, the athlete performed seven HIT blocks, varying from 7 to 11 days, each including 8-13 HIT sessions. This study provides novel insights into successful utilization of two different periodization models in the worlds best XC skier, and illustrates the macro, meso and micro- periodization of HIT blocks to increase the overall amount of HIT.

The present study investigated the effects of initial levels of cycling performance, peak oxygen uptake (O 2peak ) and gross efficiency (GE) on the subsequent adaptations of these variables and their relationship following high-intensity training (HIT) designed to increase O 2peak in competitive cyclists. Sixty cyclists (O 2peak = 61 ± 6 mL kg -1 min -1 ) were assigned a 12-week training program consisting of twenty-four supervised high-intensity interval training sessions and ad libitum low intensity training. GE was calculated at 125, 175, and 225 W and performance was determined by mean power during a 40-min time-trial (Power 40 min ). In addition to correlation analyses between initial level and pre- to post-intervention changes of the different variables, we compared these changes between four groups where participants were categorized with either low and/or high initial levels of O 2peak and GE. Average volume of high- and low-intensity training during the 12-week intervention was 1.5 ± 0.3 and 8.3 ± 2.7 h·week -1 , respectively. Following the 12-week training period, there was a significant increase in absolute and body mass normalized O 2peak and Power 40 min ( p < 0.05) and a significant decrease in GE ( p < 0.05) for all athletes pooled. There was no change in body mass following the 12-week training period. We found a moderate negative correlation between initial level of O 2peak and the change in O 2peak following the training period ( r = -0.32; p < 0.05). A small negative correlation was also found between initial Power 40 min and its change following training both when expressed in absolute power and power normalized for body mass ( r = -0.27 and -0.28; both p < 0.05). A moderate negative correlation was also found between initial levels for GE and its change following training ( r = -0.44; p < 0.01). There were no differences between the four groups based on initial levels of O 2peak and GE in the response to training on O 2peak , GE, or Power 40 min (all p > 0.12). In conclusion, the present findings suggest that there are statistically significant effects of initial levels of cycling performance and O 2peak and on the subsequent adaptations following a 12-week HIT program, but the small and moderate effects indicate limited influence on training practice.

Purpose: Although strength and sprint training are widely used methods in competitive cycling, no previous studies have compared the acute responses and recovery rates following such sessions among highly trained cyclists. The primary aim of the current study was to compare power production and biochemical markers of metabolic stress and muscle damage following a session of heavy strength (HS) and short-sprint training (SS). Methods: Eleven well-trained male cyclists (18 ± 2 years with maximal oxygen uptake of 67.2 ± 5.0 mL·kg -1 ·min -1 ) completed one HS session and one SS session in a randomized order, separated by 48 h. Power production and biochemical variables were measured at baseline and at different time points during the first 45 h post exercise. Results: Lactate and human growth hormone were higher 5 min, 30 min and 1 h post the SS compared to the HS session (all p ≤ 0.019). Myoglobin was higher following the HS than the SS session 5 min, 30 min and 1 h post exercise (all p ≤ 0.005), while creatine kinase (CK) was higher following the HS session 21 and 45 h post exercise ( p ≤ 0.038). Counter movement jump and power production during 4 sec sprint returned to baseline levels at 23 and 47 h with no difference between the HS and SS session, whereas the delayed muscle soreness score was higher 45 h following the HS compared to the SS session ( p = 0.010). Conclusion: Our findings indicate that SS training provides greater metabolic stress than HS training, whereas HS training leads to more muscle damage compared to that caused by SS training. The ability to produce power remained back to baseline already 23 h after both training sessions, indicating maintained performance levels although higher CK level and muscle soreness were present 45 h post the HS training session.

The main aim of this study was to investigate the training characteristics of the most successful female cross-country skier ever during the best period of her career. The participant won six gold medals at the Olympic Games, 18 gold medals at the World Championship, and 110 World Cup victories. Day-to-day training diary data, interviews, and physiological tests were analyzed. Training data was systemized by training form (endurance, strength, and speed), intensity [low- (LIT), moderate- (MIT), and high-intensity training (HIT)], and mode (running, cycling, and skiing/roller skiing), followed by a division into different periodization phases. Specific sessions utilized in the various periodization periods and the day-to-day periodization of training, in connection with altitude camps and tapering toward major championships, were also analyzed. Following a 12-year nonlinear increase in training load, the annual training volume during the five consecutive successful years stabilized at 937 ± 25 h, distributed across 543 ± 9 sessions. During these 5 years, total training time was distributed as 90.6% endurance-, 8.0% strength-, and 1.4% speed-training, with endurance-training time consisting of 92.3 ± 0.3% LIT, 2.9 ± 0.5% MIT, and 4.8 ± 0.5% HIT. Total LIT-time consisted of 21% warm-up, 14% sessions <90 min, and 65% long-duration sessions >90 min. While the total number of LIT sessions remained stable across phases (32 sessions), total LIT-time was reduced from GP (76 h/month) to SP (68 h/month) and CP (55 h/month). MIT-time decreased from GP (2.8 h/month) to SP (2.2 h/month) and CP (1 h/month). HIT-time increased from GP (2.8 h/month) to SP (3.2 h/month) and CP (4.7 h/month). Altitude training accounted for 18-25% of annual training volume and performed across relatively short training camps (≤16 days) with a clear reduction of HIT training, but increased total and LIT volume compared to sea-level training. Training before international championships included a 2-week increase in LIT and strength volume followed by a gradual reduction of training volume and increased HIT during the last week. This study provides unique data on the world's most successful female cross-country skier's long-term training process, including novel information about the distribution of and interplay between sessions of different forms, intensities, and exercise modes throughout the annual season.

Purpose: Investigate development of specific performance adaptions and hormonal responses every fourth week during a 12-wk high-intensity training (HIT) period in groups with different interval-training prescriptions., Methods: Sixty-three well-trained cyclists performing a 12-wk intervention consisting of two to three HIT sessions per week in addition to ad libitum low-intensity training. Groups were matched for total training load, but increasing HIT (INC) group (n = 23) performed interval-sessions as 4 × 16 min in weeks 1-4, 4 × 8 min in weeks 5-8, and 4 × 4 min in weeks 9-12. Decreasing HIT (DEC) group (n = 20) performed interval sessions in the opposite order as INC, and mixed HIT (MIX) group (n = 20) performed all interval-sessions in a mixed distribution during 12 wk. Cycling-tests and measures of resting blood hormones were conducted pre, weeks 4, 8, and 12., Results: INC and MIX achieved >70% of total change in workload eliciting 4 mmol·L [la] (Power4mM) and V˙O2peak during weeks 1-4, versus only 34%-38% in DEC. INC induced larger improvement versus DEC during weeks 1-4 in Power4mM (effect size, 0.7) and V˙O2peak (effect size, 0.8). All groups increased similarly in peak power output during weeks 1-4 (64%-89% of total change). All groups' pooled, total and free testosterone and free testosterone/cortisol ratio decreased by 22% ± 15%, 13% ± 23%, and 14% ± 31% (all P < 0.05), and insulin-like growth factor-1 increased by 10% ± 14% (P < 0.05) during weeks 1-4., Conclusions: Most of progression in Power4mM, V˙O2peak and peak power output was achieved during weeks 1-4 in INC and MIX, and accompanied by changes in resting blood hormones consistent with increased but compensable stress load. In these well-trained subjects, accumulating 2-3 h·wk performing 4 × 16 min work bouts at best effort induces greater adaptions in Power4mM and V˙O2peak than accumulating ~1 h·wk performing best effort intervals as 4 × 4 min.

Purpose: This study aimed to compare the effects of three different high-intensity training (HIT) models, balanced for total load but differing in training plan progression, on endurance adaptations., Methods: Sixty-three cyclists (peak oxygen uptake (V˙O2peak) 61.3 ± 5.8 mL·kg·min) were randomized to three training groups and instructed to follow a 12-wk training program consisting of 24 interval sessions, a high volume of low-intensity training, and laboratory testing. The increasing HIT group (n = 23) performed interval training as 4 × 16 min in weeks 1-4, 4 × 8 min in weeks 5-8, and 4 × 4 min in weeks 9-12. The decreasing HIT group (n = 20) performed interval sessions in the opposite mesocycle order as the increasing HIT group, and the mixed HIT group (n = 20) performed the interval prescriptions in a mixed distribution in all mesocycles. Interval sessions were prescribed as maximal session efforts and executed at mean values 4.7, 9.2, and 12.7 mmol·L blood lactate in 4 × 16-, 4 × 8-, and 4 × 4-min sessions, respectively (P < 0.001). Pre- and postintervention, cyclists were tested for mean power during a 40-min all-out trial, peak power output during incremental testing to exhaustion, V˙O2peak, and power at 4 mmol·L lactate., Results: All groups improved 5%-10% in mean power during a 40-min all-out trial, peak power output, and V˙O2peak postintervention (P < 0.05), but no adaptation differences emerged among the three training groups (P > 0.05). Further, an individual response analysis indicated similar likelihood of large, moderate, or nonresponses, respectively, in response to each training group (P > 0.05)., Conclusions: This study suggests that organizing different interval sessions in a specific periodized mesocycle order or in a mixed distribution during a 12-wk training period has little or no effect on training adaptation when the overall training load is the same.

The present study investigated the contribution of performance on uphill, flat, and downhill sections to overall performance in an international 10-km classical time-trial in elite female cross-country skiers, as well as the relationships between performance on snow and laboratory-measured physiological variables in the double poling (DP) and diagonal (DIA) techniques. Ten elite female cross-country skiers were continuously measured by a global positioning system device during an international 10-km cross-country skiing time-trial in the classical technique. One month prior to the race, all skiers performed a 5-min submaximal and 3-min self-paced performance test while roller skiing on a treadmill, both in the DP and DIA techniques. The time spent on uphill (r = 0.98) and flat (r = 0.91) sections of the race correlated most strongly with the overall 10-km performance (both p < 0.05). Approximately 56% of the racing time was spent uphill, and stepwise multiple regression revealed that uphill time explained 95.5% of the variance in overall performance (p < 0.001). Distance covered during the 3-min roller-skiing test and body-mass normalized peak oxygen uptake (VO2peak) in both techniques showed the strongest correlations with overall time-trial performance (r = 0.66-0.78), with DP capacity tending to have greatest impact on the flat and DIA capacity on uphill terrain (all p < 0.05). Our present findings reveal that the time spent uphill most strongly determine classical time-trial performance, and that the major portion of the performance differences among elite female cross-country skiers can be explained by variations in technique-specific aerobic power.

Unlabelled: Performing at an elite level in Nordic combined (NC) requires both the explosiveness required for ski jumping performance and the endurance capacity required for cross-country skiing., Purpose: To describe the characteristics of world-class NC athletes' training and determine how endurance and non-endurance (ie, strength, power, and ski jumping) training is periodized., Methods: Annual training characteristics and the periodization of endurance and non-endurance training were determined by analyzing the training diaries of 6 world-class NC athletes., Results: Of 846 ± 72 annual training hours, 540 ± 37 h were endurance training, with 88.6% being low-, 5.9% moderate-, and 5.5% high-intensity training. While training frequency remained relatively constant, the total training volume was reduced from the general preparatory to the competition phase, primarily due to less low- and moderate-intensity training (P < .05). A total of 236 ± 55 h/y were spent as non-endurance training, including 211 ± 44 h of power and ski-jump-specific training (908 ± 165 ski jumps and ski-jump imitations). The proportion of non-endurance training increased significantly toward the competition phase (P < .05)., Conclusion: World-class NC athletes reduce the volume of low- and moderate-intensity endurance training toward the competition phase, followed by an increase in the relative contribution of power and ski-jump training. These data provide novel insight on how successful athletes execute their training and may facilitate more-precise coaching of future athletes in this sport. In addition, this information is of high relevance for the training organization of other sports that require optimization of 2 fundamentally different physical capacities.

Aim: To examine symptoms indicative of respiratory tract and gastrointestinal infections and determine risk factors for such symptoms in elite cross-country skiers., Methods: Self-reported training and symptom data for 37 elite cross-country skiers from 2007 to 2015 were analysed using multilevel logistic regression equations with symptom incidence and duration as outcome variables, and sex, performance level, season, competition, air travel, altitude exposure and training characteristics as independent variables., Results: Data for 7016 person-weeks were analysed, including 464 self-reported infection events and 110 959 h of training. Athletes reported median (range) 3 (1-7) respiratory tract and/or gastrointestinal events per year, with symptoms lasting 5 (1-24) days. During the winter, symptoms occurred more frequently (OR 2.09, p<0.001) and lasted longer (b=0.043, p<0.001) compared with summer. Competition and air travel increased the risk of symptoms, with ORs of 2.93 (95% CI 2.24 to 3.83) and 4.94 (95% CI 3.74 to 6.53), respectively (p<0.001). Athletes with higher training monotony had lower risk of symptoms (OR 0.87 (95% CI 0.73 to 0.99), p<0.05). Other training variables were not associated with symptoms. Athletes who had won an Olympic/World Championship medal reported shorter symptom duration compared with less successful athletes (b=-0.019, p<0.05) resulting in significantly fewer symptomatic days/year (14 (6-29) vs 22 (8-43) days/year)., Conclusions: Air travel and competition are major risk factors for acute respiratory tract and gastrointestinal symptoms in this population. Athletes who have large fluctuations in training load experience such symptoms more frequently. Shorter duration of symptoms appears to be associated with success in cross-country skiing., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/)

Purpose: The objective of this study is to compare the physiological capacity and training characteristics of the world's six highest ranked female cross-country skiers (world class (WC)) with those of six competitors of national class (NC)., Methods: Immediately before the start of the competition season, all skiers performed three 5-min submaximal stages of roller skiing on a treadmill for measurement of oxygen cost, as well as a 3-min self-paced performance test using both the double poling (DP) and diagonal stride (DIA) techniques. During the 3-min performance tests, the total distance covered, peak oxygen uptake (V˙O2peak), and accumulated oxygen deficit were determined. Each skier documented the intensity and mode of their training during the preceding 6 months in a diary., Results: There were no differences between the groups with respect to oxygen cost or gross efficiency at the submaximal speeds. The WC skiers covered 6%-7% longer distances during the 3-min tests and exhibited average V˙O2peak values of ∼70 and ∼65 mL·min·kg with DIA and DP, respectively, which were 10% and 7% higher than the NC skiers (all P < 0.05). However, the accumulated oxygen deficit did not differ between groups. From May to October, the WC skiers trained a total of 532 ± 73 h (270 ± 26 sessions) versus 411 ± 62 h (240 ± 27 sessions) for the NC skiers. In addition, the WC skiers performed 26% more low-intensity and almost twice as much moderate-intensity endurance and speed training (all P < 0.05)., Conclusions: This study highlights the importance of a high oxygen uptake and the ability to use this while performing the different skiing techniques on varying terrains for female cross-country skiers to win international races. In addition, the training data documented here provide benchmark values for female endurance athletes aiming for medals.

Background: The purpose of this study was to quantify differences in anthropometrical and physical characteristics according to playing position and competitive level in male elite handball., Methods: One hundred and seventy-six national team and 1st division players (age 23±4 years, body mass 89±11 kg, body height 188±5 cm) participated in the study. All participants were tested on throwing velocity, 20-meter sprint, countermovement jump, 3000-meter run, 1RM squat and bench press., Results: Back players achieved higher throwing velocities compared to other positions. National team back players achieved higher velocities in set shots (9.4%, P<0.001, d=1.5) and jump shots (8.1%, P<0.001, d=1.5) than 1st division players. Wings sprinted faster than pivots (3.5%, P<0.001, d=1.2) and goalkeepers (5.4%, P<0.001, d=1.2). Wings jumped higher than pivots (13.0%, P<0.001, d=1.0) and goalkeepers (11.4%, P=0.003, d=0.9). National team back players ran faster than 1st division back players over 3000 meters (4.9%, P=0.011, d=0.7). Back players showed better relative strength in squat than pivots (12.1%, P=0.016, d=0.7). Wings had better relative strength in squat that pivots (17.4%, P=0.001, d=1.0) and goalkeepers (13.1%, P=0.016, d=0.8). Pivots were 8.9% stronger than wing players (P=0.044, d=0.7) in 1RM bench press., Conclusions: Varying on-court demands in handball are reflected by different physical and physiological characteristics across playing standard and positions. Physical conditioning of players should therefore be individualized and targeted to solve the position-dependent tasks during play.

Purpose: A review of published studies monitoring sprint performance reveals considerable variation in start distance behind the initial timing gate. The aim of the current study was to generate correction factors across varying flying-start distances used in sprint testing with photocells., Methods: Forty-four well-trained junior soccer players (age 18.2 ± 1.0 y, height 175 ± 8 cm, body mass 68.4 ± 8.9 kg) performed sprint testing on an indoor sprint track. They were allocated to 3 groups based on sprint-performance level. Times for 10- and 200-m sprint with foot placement ranging from 0.5 to 15 m back from the initial timing gate were recorded twice for each athlete., Results: Correction-factor equation coefficients were generated for each of the 3 analyzed groups derived from the phase-decay equation y = (y0 - PL) × exp(-k × x) + PL, where y = time difference (0.5-m flying start as reference), x = flying-start distance, y0 is the y value when time is zero, PL (plateau) is the y value at infinite times, and k is the rate constant, expressed in reciprocal of the x-axis time units; if x is in seconds, then k is expressed in inverse seconds. R2 was ≥.998 across all athlete groups and sprint distances, demonstrating excellent goodness of fit. Within-group time differences were significant (P < .05) across all flying-start distance checkpoints for all groups. Between-groups time-saving differences up to 0.04 s were observed between the fastest and the slowest groups (P < .05)., Conclusions: Small changes in flying-start distances can cause time differences larger than the typical gains made from specific training, or even the difference between the fastest and slowest elite team-sport athletes. The presented correction factors should facilitate more meaningful comparisons of published sprint-performance results.

Purpose: To generate updated Olympic-medal benchmarks for VO2max in winter endurance disciplines, examine possible differences in VO2max between medalists and nonmedalists, and calculate gender difference in V˙ O2max based on a homogeneous subset of world-leading endurance athletes., Methods: The authors identified 111 athletes who participated in winter Olympic Games/World Championships in the period 1990 to 2013. All identified athletes tested VO2max at the Norwegian Olympic Training Center within ±1 y of their championship performance. Testing procedures were consistent throughout the entire period., Results: For medal-winning athletes, the following relative VO2max values (mean:95% confidence intervals) for men/women were observed (mL · min-1 · kg-1): 84:87-81/72:77-68 for cross-country distance skiing, 78:81-75/68:73-64 for cross-country sprint skiing, 81:84-78/67:73-61 for biathlon, and 77:80-75 for Nordic combined (men only). Similar benchmarks for absolute VO2max (L/min) in male/female athletes are 6.4:6.1-6.7/4.3:4.1-4.5 for cross-country distance skiers, 6.3:5.8-6.8/4.0:3.7-4.3 for cross-country sprint skiers, 6.2:5.7-6.4/4.0:3.7-4.3 for biathletes, and 5.3:5.0-5.5 for Nordic combined (men only). The difference in relative VO2max between medalists and nonmedalists was large for Nordic combined, moderate for cross-country distance and biathlon, and small/trivial for the other disciplines. Corresponding differences in absolute VO2max were small/trivial for all disciplines. Male cross-country medalists achieve 15% higher relative VO2max than corresponding women., Conclusions: This study provides updated benchmark VO2max values for Olympic-medal-level performance in winter endurance disciplines and can serve as a guideline of the requirements for future elite athletes.

Introduction: Sex-specific differences that arise during puberty have a pronounced effect on the training process. However, the consequences this should have for goal-setting, planning and implementation of training for boys and girls of different ages remains poorly understood. The aim of this study was to quantify performance developments in athletic running and jumping disciplines in the age range 11-18 and identify progression differences as a function of age, discipline and sex., Methods: The 100 all-time best Norwegian male and female 60-m, 800-m, long jump and high jump athletes in each age category from 11 to 18 years were analysed using mixed models with random intercept according to athlete., Results: Male and female athletes perform almost equally in running and jumping events up to the age of 12. Beyond this age, males outperform females. Relative annual performance development in females gradually decreases throughout the analyzed age period. In males, annual relative performance development accelerates up to the age of 13 (for running events) or 14 (for jumping events) and then gradually declines when approaching 18 years of age. The relative improvement from age 11 to 18 was twice as high in jumping events compared to running events. For all of the analyzed disciplines, overall improvement rates were >50% higher for males than for females. The performance sex difference evolves from < 5% to 10-18% in all the analyzed disciplines from age 11 to 18 yr., Conclusion: To the authors' knowledge, this is the first study to present absolute and relative annual performance developments in running and jumping events for competitive athletes from early to late adolescence. These results allow coaches and athletes to set realistic goals and prescribe conditioning programs that take into account sex-specific differences in the rate of performance development at different stages of maturation.

The aims of the present study were to compare the effects of 1) training at 90 and 100% sprint velocity and 2) supervised versus unsupervised sprint training on soccer-specific physical performance in junior soccer players. Young, male soccer players (17 ± 1 yr, 71 ± 10 kg, 180 ± 6 cm) were randomly assigned to four different treatment conditions over a 7-week intervention period. A control group (CON, n = 9) completed regular soccer training according to their teams' original training plans. Three training groups performed a weekly repeated-sprint training session in addition to their regular soccer training sessions performed at A) 100% intensity without supervision (100UNSUP, n = 13), B) 90% of maximal sprint velocity with supervision (90SUP, n = 10) or C) 90% of maximal sprint velocity without supervision (90UNSUP, n=13). Repetitions x distance for the sprint-training sessions were 15 x 20 m for 100UNSUP and 30 x 20 m for 90SUP and 90UNSUP. Single-sprint performance (best time from 15 x 20 m sprints), repeated-sprint performance (mean time over 15 x 20 m sprints), countermovement jump and Yo-Yo Intermittent Recovery Level 1 (Yo-Yo IR1) were assessed during pre-training and post-training tests. No significant differences in performance outcomes were observed across groups. 90SUP improved Yo-Yo IR1 by a moderate margin compared to controls, while all other effect magnitudes were trivial or small. In conclusion, neither weekly sprint training at 90 or 100% velocity, nor supervised sprint training enhanced soccer-specific physical performance in junior soccer players.

Human upper performance limits in the 100-m sprint remain the subject of much debate. The aim of this commentary is to highlight the vulnerabilities of prognoses from historical trends by shedding light on the mechanical and physiological limitations associated with human sprint performance. Several conditions work against the athlete with increasing sprint velocity; air resistance and braking impulse in each stride increase while ground-contact time typically decreases with increasing running velocity. Moreover, muscle-force production declines with increasing speed of contraction. Individual stature (leg length) strongly limits stride length such that conditioning of senior sprinters with optimized technique mainly must be targeted to enhance stride frequency. More muscle mass means more power and thereby greater ground-reaction forces in sprinting. However, as the athlete gets heavier, the energy cost of accelerating that mass also increases. This probably explains why body-mass index among world-class sprinters shows low variability and averages 23.7±1.5 and 20.4±1.4 for male and female sprinters, respectively. Performance development of world-class athletes indicates that ~8% improvement from the age of 18 represents the current maximum trainability of sprint performance. However, drug abuse is a huge confounding factor associated with such analyses, and available evidence suggests that we are already very close to "the citius end" of 100-m sprint performance.

One year of training data from 8 elite orienteers were divided into a transition phase (TP), general preparatory phase (GPP), specific preparatory phase (SPP), and competition phase (CP). Average weekly training volume and frequency, hours at different intensities (zones 1-3), cross-training, running, orienteering, interval training, continuous training, and competition were calculated. Training volume was higher in GPP than TP, SPP, and CP (14.9 vs 9.7, 11.5, and 10.6 h/wk, P < .05). Training frequency was higher in GPP than TP (10 vs 7.5 sessions/wk, P < .05). Zone 1 training was higher in GPP than TP, SPP, and CP (11.3 vs 7.1, 8.3, and 7.7 h/wk, P < .05). Zone 3 training was higher in SPP and CP than in TP and GPP (0.9 and 1.1 vs 1.6 and 1.5 h/ wk, P < .05). Cross-training was higher in GPP than SPP and CP (4.3 vs 0.8 h/wk, P < .05). Interval training was higher in GPP than TP, SPP, and CP (0.7 vs 0.3 h/wk, P < .05). High-intensity continuous training was higher in GPP than CP (0.9 vs 0.4 h/ wk, P < .05), while competition was higher in SPP and CP than in TP and GPP (1.3 and 1.5 vs 0.6 and 0.3 h/wk, P < .01). In conclusion, these champion endurance athletes achieved a progressive reduction in total training volume from GPP to CP via a shortening of each individual session while the number of training sessions remained unchanged. This decrease in training volume was primarily due to a reduction in the number of hours of low-intensity, non-sport-specific cross-training.

Valid and reliable measures of sprint times are necessary to detect genuine changes in sprinting performance. It is currently difficult for practitioners to assess which timing system meets this demand within the constraints of a proper cost-benefit analysis. The purpose of this investigation was to quantify sprint time differences between single-beam (SB) and dual-beam (DB) timing systems. Single-beam and DB photocells were placed at 0, 20, and 40 m to compare 0-20 and 20-40 m sprint times. To control for the influence of swinging limbs between devices, 2 recreationally active participants cycled as fast as possible through the track 25 times with a 160-cm tube (18 cm diameter) vertically mounted in front of the bike. This protocol produced a coefficient of variation (CV) of 0.4 and 0.7% for 0-20 and 20-40 m sprint times, respectively while SEM was 0.01 seconds for both distances. To address the primary research question, 25 track and field athletes (age, 19 ± 1 years; height, 174 ± 8 cm; body mass, 67 ± 10 kg) performed two 40 m sprints. This protocol produced a CV of 1.2 and 1.4% for 0-20 and 20-40 m, respectively while SEM was 0.02 seconds for both distances. The magnitude of time differences was in the range of ±0.05-0.06 seconds. We conclude that DB timing is required for scientists and practitioners wishing to derive accurate and reliable short sprint results.

Purpose: To describe training variations across the annual cycle in Olympic and World Champion endurance athletes, and determine whether these athletes used tapering strategies in line with recommendations in the literature., Methods: Eleven elite XC skiers and biathletes (4 male; 28±1 yr, 85±5 mL x min(-1) x kg(-1) VO2max, 7 female, 25±4 yr, 73±3 mL x min(-1) x kg(-1) VO2max) reported one year of day-to-day training leading up to the most successful competition of their career. Training data were divided into periodization and peaking phases and distributed into training forms, intensity zones and endurance activity forms., Results: Athletes trained ∼800 h/500 sessions x year(-1), including ∼500 h x year(-1) of sport-specific training. Ninety-four percent of all training was executed as aerobic endurance training. Of this, ∼90% was low intensity training (LIT, below the first lactate threshold) and 10% high intensity training (HIT, above the first lactate threshold) by time. Categorically, 23% of training sessions were characterized as HIT with primary portions executed at or above the first lactate turn point. Training volume and specificity distribution conformed to a traditional periodization model, but absolute volume of HIT remained stable across phases. However, HIT training patterns tended to become more polarized in the competition phase. Training volume, frequency and intensity remained unchanged from pre-peaking to peaking period, but there was a 32±15% (P<.01) volume reduction from the preparation period to peaking phase., Conclusions: The annual training data for these Olympic and World champion XC skiers and biathletes conforms to previously reported training patterns of elite endurance athletes. During the competition phase, training became more sport-specific, with 92% performed as XC skiing. However, they did not follow suggested tapering practice derived from short-term experimental studies. Only three out of 11 athletes took a rest day during the final 5 days prior to their most successful competition.

Purpose: To quantify VO2max among female competitive soccer players as a function of performance level, field position, and age. In addition, the evolution of VO2max among world-class players over an 18-y period was quantified., Methods: Female players (N = 199, 22 ± 4 y, 63 ± 6 kg, height 169 ± 6 cm), including an Olympic winning squad, were tested for VO2max at the Norwegian Olympic Training Center between 1989 and 2007., Results: National-team players had 5% higher VO2max than 1st-division players (P = .042, d = 0.4), 13% higher than 2nd-division players (P < .001, d = 1.2), and 9% higher than junior players (P = .005, d = 1.0). Midfielders had 8% higher VO2max than goalkeepers (P = .048, d = 1.1). No significant differences were observed across outfield players or different age categories. There was a trend toward lower relative VO2max across time epochs., Conclusions: This study demonstrated that VO2max varies across playing-standard level in women's soccer. No significant differences in VO2max were observed across outfield positions and age categories. Over time, there has been a slight negative development in VO2max among elite Norwegian soccer players.

The overall objective of this review was to investigate the role and development of sprinting speed in soccer. Time-motion analyses show that short sprints occur frequently during soccer games. Straight sprinting is the most frequent action before goals, both for the scoring and assisting player. Straight-line sprinting velocity (both acceleration and maximal sprinting speed), certain agility skills, and repeated-sprint ability are shown to distinguish groups from different performance levels. Professional players have become faster over time, indicating that sprinting skills are becoming more and more important in modern soccer. In research literature, the majority of soccer-related training interventions have provided positive effects on sprinting capabilities, leading to the assumption that all kinds of training can be performed with success. However, most successful intervention studies are time consuming and challenging to incorporate into the overall soccer training program. Even though the principle of specificity is clearly present, several questions remain regarding the optimal training methods within the larger context of the team-sport setting. Considering time-efficiency effects, soccer players may benefit more by performing sprint-training regimens similar to the progression model used in strength training and by world-leading athletics practitioners, compared with the majority of guidelines that traditionally have been presented in research literature.

Purpose: The authors directly compared 3 frequently used methods of heart-rate-based training-intensity-distribution (TID) quantification in a large sample of training sessions performed by elite endurance athletes., Methods: Twenty-nine elite cross-country skiers (16 male, 13 female; 25 ± 4 y; 70 ± 11 kg; 76 ± 7 mL · min-1 · kg-1 VO2max) conducted 570 training sessions during a ~14-d altitude-training camp. Three analysis methods were used: time in zone (TIZ), session goal (SG), and a hybrid session-goal/time-in-zone (SG/TIZ) approach. The proportion of training in zone 1, zone 2, and zone 3 was quantified using total training time or frequency of sessions, and simple conversion factors across different methods were calculated., Results: Comparing the TIZ and SG/TIZ methods, 96.1% and 95.5%, respectively, of total training time was spent in zone 1 (P < .001), with 2.9%/3.6% and 1.1%/0.8% in zones 2/3 (P < .001). Using SG, this corresponded to 86.6% zone 1 and 11.1%/2.4% zone 2/3 sessions. Estimated conversion factors from TIZ or SG/TIZ to SG and vice versa were 0.9/1.1, respectively, in the low-intensity training range (zone 1) and 3.0/0.33 in the high-intensity training range (zones 2 and 3)., Conclusions: This study provides a direct comparison and practical conversion factors across studies employing different methods of TID quantification associated with the most common heart-rate-based analysis methods.