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Challenges facing mother-athletes (MAs) have aroused research and media attention in recent years, with an increasing number of sportswomen attempting to successfully combine pregnancy and motherhood with an elite athletic career. The aims of this study were to explore how MA-specific challenges manifest in elite cross-country skiing in Scandinavia and to better understand how female athletes balance their priorities as they initiate, maintain, and/or discontinue their role as a MA. Qualitative data were collected through semistructured interviews with 13 female cross-country skiers from Norway and Sweden. Thematic analyses revealed four MA-specific challenges facing the athletes: (a) Biological clock versus peak performance, (b) Maintaining fitness versus training safely, (c) Receiving support versus facing deselection, and (d) Balancing competing MA demands. Many of the athletes felt pressured into prioritizing either motherhood or athletic excellence, particularly in their early to mid-30s when the window of opportunity for building a family was considered limited. Further, maintaining fitness and training safely during pregnancy were perceived as a challenge, as was balancing the MA role after childbirth. In many cases, athletes felt uncertain about whether they would receive support from their team or federation. Moreover, there were expectations of incompatibility surrounding the MA role. More research and educational efforts to promote MA-specific knowledge, as well as developing structured processes and providing policies to support female athletes, are identified as vital future steps. These measures may prolong athletic careers and enhance well-being for elite female athletes. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effects of wearing upper- and lower-body compression garments on cross-country skiing performance in elite winter biathletes. Methods: A total of 7 senior biathletes (4 men and 3 women) from the Swedish national team performed 2 exercise trials in a randomized and counterbalanced order, wearing either commercially available upper- and lower-body compression garments (COMP) or a standard winter-biathlon racing suit (CON). In each trial, the athletes roller-skied on a customized treadmill, completing a time trial simulating the skiing duration of a biathlon sprint race, followed by a time-to-exhaustion test designed to elicit exhaustion within ∼60 to 90 seconds. Heart rate, blood lactate concentration, rating of perceived exertion, thermal sensation, and thermal comfort were monitored throughout each trial, while muscle soreness was measured up to 48 hours after each trial. Results: Pressure exerted by the clothing was significantly higher at all anatomical sites for COMP compared with CON (P ≤.002). Wearing COMP led to small positive effects on time-trial (d = 0.31) and time-to-exhaustion test (d = 0.31) performances compared with CON, but these differences were not statistically significant (P >.05). No significant differences were found for any physiological (heart rate or blood lactate concentration) or subjective (rating of perceived exertion, thermal sensation, thermal comfort, or muscle soreness) responses between COMP and CON (P >.05). Conclusion: Wearing COMP during maximal cross-country skiing may have small but worthwhile beneficial effects on performance for some individuals. Due to individual variation, athletes are advised to test COMP prior to competition. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to investigate how rifle carriage and skiing speed during biathlon roller skiing affect range of motion (ROM) in joint angles and equipment (skis and poles), the vertical distance between shoulders and treadmill (vertdist), as well as possible sex differences associated with rifle carriage. Methods: Fourteen biathletes (6 women, 8 men) roller‐skied on a treadmill at submaximal and simulated race speeds, with (WR) and without (NR) a rifle, using gears 3 and 2. Kinematical data for the whole body, poles, roller‐skis, rifle, and treadmill were monitored using a 3D motion capture system. Movements determined as flexion/extension (x), abduction/adduction (y), and/or internal/external rotation (z) were analyzed for the hip, shoulder, thorax, knee, ankle, elbow, poles, and roller skis. ROM (the difference between maximal and minimal angles) in joints and equipment, and vertdist were analyzed over six skiing cycles during each condition (WR and NR) and speed. Results: The maximal vertdist was lower for WR compared with NR (gear 3: 1.53 ± 0.06 vs 1.54 ± 0.06 m; gear 2: 1.49 ± 0.06 vs 1.51 ± 0.06 m; both p < 0.001). ROM in the upper body was altered when roller skiing WR (movements decreased in thorax and shoulder (x) and increased in elbow (only gear 3) (x), thorax (only gear 2), and shoulder (y) and (z); all p < 0.05) and increased with speed, without differences between sexes (p > 0.05). Conclusion: Since rifle carriage and speed appear to affect the kinematics of roller skiing, coaches, and biathletes are advised to perform skiing technique training under competition‐like conditions (i.e., at race speeds while carrying the rifle). [ABSTRACT FROM AUTHOR]

Introduction: Exercise-induced laryngeal obstruction (EILO) is a differential diagnosis for asthma and prevalent in athletes referred for exercise-induced dyspnea. The aim of this study was to estimate the prevalence of EILO in elite cross-country skiers, known for a high prevalence of asthma. Method: Elite cross-country skiers were invited for screening of EILO. Screening consisted of clinical assessment, questionnaires, skin prick test, spirometry, eucapnic voluntary hyperventilation test, and continuous laryngoscopy during exercise test. Current asthma was defined as physician-diagnosed asthma and use of asthma medication during the last 12 months. EILO was defined as ≥2 points at the supraglottic or glottic level during exercise at maximal effort, using a visual grade score system. Result: A total of 89 (51% female) cross-country skiers completed the study. EILO was identified in 27% of the skiers, 83% of whom were female. All skiers with EILO had supraglottic EILO, and there was no glottic EILO. Current asthma was present in 34 (38%) of the skiers, 10 (29%) of whom had concomitant EILO. In the skiers with EILO, a higher proportion reported wheeze or shortness of breath after exercise, compared with skiers without EILO. In skiers with EILO and current asthma, compared with skiers with asthma only, a higher proportion reported wheeze or shortness of breath after exercise. Asthma medication usage did not differ between these groups. Conclusion: EILO is common in elite cross-country skiers, especially females. Asthma and EILO may coexist, and the prevalence of respiratory symptoms is higher in skiers with both. Testing for EILO should be considered in cross-country skiers with respiratory symptoms. [ABSTRACT FROM AUTHOR]

Background: The relative age effect (RAE) is a worldwide phenomenon, allowing sport participation and elite selection to be based on birthdate distribution. Negative consequences include both a narrow, non-optimal elite selection and negative health effects on entire populations. This study investigated the RAE and athletic performance in multiple individual sports in Sweden. Methods: Birthdates of athletes born between the years 1922 and 2015 were collected across 4-month periods (tertiles: T1, T2, T3) from cross-country skiing (N = 136,387), orienteering (N = 41,164), athletics (N = 14,503), alpine skiing (N = 508), E-sports (N = 47,030), and chess (N = 4889). In total, data from 244,560 athletes (women: N = 79,807, men: N = 164,753) was compared to the complete parent population of 5,390,954 births in Sweden during the same years. Chi-squared statistics compared parent and cohort distributions stratified by sport, sex, and age. Results: A significantly skewed distribution of birthdates was present in all sports, both sexes, and most age groups. The largest RAEs are seen in children where T1 often constitutes 40–50% and T3, 20–25% of the population. In E-sports, an inversed RAE was seen in adults. In most investigated sports, birthdate distribution was correlated to performance in children but not in adults. Conclusions: Skewed birthdate distributions were consistently prevalent in all investigated individual sports in Sweden, both physically demanding and cognitive/skill-based. As sport participation is related to total level of physical activity, both present and future, failing to address the RAE issue at an early age will result not only in a narrow and arbitrary selection for adult elite athletes but also in a negative impact on public health. [ABSTRACT FROM AUTHOR]

Cross-country (XC) skiing has been an Olympic event since the first Winter Games in Chamonix, France, in 1924. Due to more effective training and tremendous improvements in equipment and track preparation, the speed of Olympic XC-ski races has increased more than that of any other Olympic endurance sport. Moreover, pursuit, mass-start, and sprint races have been introduced. Indeed, 10 of the 12 current Olympic competitions in XC skiing involve mass starts, in which tactics play a major role and the outcome is often decided in the final sprint. Accordingly, reappraisal of the success factors for performance in this context is required. The very high aerobic capacity (VO2max) of many of today's world-class skiers is similar that of their predecessors. At the same time, the new events provide more opportunities to profit from anaerobic capacity, upper-body power, high-speed techniques, and "tactical flexibility." The wide range of speeds and slopes involved in XC skiing requires skiers to continuously alternate between and adapt different subtechniques during a race. This technical complexity places a premium on efficiency. The relative amounts of endurance training performed at different levels of intensity have remained essentially constant during the past 4 decades. However, in preparation for the Sochi Olympics in 2014, XC skiers are performing more endurance training on roller skis on competition-specific terrain, placing greater focus on upper-body power and more systematically performing strength training and skiing at high speeds than previously. [ABSTRACT FROM AUTHOR]

Purpose: This study investigated whether there is a correlation between time-trial performance and competitive performance capacity of male and female junior cross-country skiers and sought to explain sex-specific competitive performance capacity through multiple-regression modeling. Methods: The International Ski Federation's (FIS) junior ranking points for distance (FISdist) and sprint (FISsprint) competitions were used as performance parameters. A total of 38 elite junior (age 18.5 ± 1.0 y) cross-country skiers (24 men and 14 women) completed 3 time-trial tests: a 3-km level-running time trial (TTRun), a 2-km moderate uphill (1.2o slope) roller-skiing time trial using the double-poling technique (TTDP), and a 2-km uphill (2.8o slope) roller-skiing time trial using the diagonal-stride technique (TTDiag). The correlations were investigated using Pearson correlation analysis, and regression models were created using multiple-linear-regression analysis. Results: For men, FISsprint and FISdist were correlated with the times for TTRun, TTDP, and TTDiag (all P < .001). For women, FISsprint was correlated with the times for TTRun (P < .05), TTDP (P < .01), and TTDiag (P < .01), whereas FISdist was correlated only with the times for TTDP (P < .01) and TTDiag (P < .05). The models developed for FISdist and FISsprint explained 73.9-82.3% of the variance in the performance capacity of male junior cross-country skiers. No statistically valid regression model was found for the women. Conclusions: Running and roller-skiing time trials are useful tests for accurately predicting the performance capacity of junior cross-country skiers. [ABSTRACT FROM AUTHOR]

This study examined the influence of turn radius on velocity and energy profiles when skidding and step turning during more and less effective downhill turns while cross-country skiing. Thirteen elite female cross-country skiers performed single turns with a 9- or 12-m radius using the skidding technique and a 12- or 15-m radius with step turning. Mechanical parameters were monitored using a real-time kinematic Global Navigation Satellite System and video analysis. Step turning was more effective during all phases of a turn, leading to higher velocities than skidding (P < .05). With both techniques, a greater radius was associated with higher velocity (P < .05), but the quality of turning, as assessed on the basis of energy characteristics, was the same. More effective skidding turns involved more pronounced deceleration early in the turn and maintenance of higher velocity thereafter, while more effective step turning involved lower energy dissipation during the latter half of the turn. In conclusion, the single-turn analysis employed here reveals differences in the various techniques chosen by elite cross-country skiers when executing downhill turns of varying radii and can be used to assess the quality of such turns. [ABSTRACT FROM AUTHOR]

Background: Hypertension is the leading risk factor for death worldwide, and high levels of physical activity are associated with a lower incidence of hypertension. The associations of excessive levels of exercise and incidence of hypertension are less well known. We aim to compare the incidence of hypertension among 206 889 participants in a long-distance cross-country skiing event and 505 542 people randomly sampled from the general population (matched to the skiers on age, sex, and place of residence).Methods: Skiers' best performance (in percent of winning time) and number of completed races during the study period were associated with incidence of hypertension after participation in Vasaloppet. Hypertension was defined as prescription of blood pressure-lowering drugs as obtained from the national drug registry. Models were adjusted for sex, age, education, and income (total effect).Results: During a median time of risk of 8.3 years, skiers had a lower incidence of hypertension compared with nonskiers (hazard ratio [HR], 0.59 [95% CI, 0.58-0.60]). Among the skiers, better performance (in percent of winning time) in Vasaloppet was strongly associated with a lower incidence of hypertension (fastest fifth: HR, 0.41 [95% CI, 0.39-0.42]; slowest fifth: HR, 0.78 [95% CI, 0.75-0.81]). The association was nearly linear and did not differ between sexes. Among the skiers, a weaker association was seen between the number of completed races during the study period and the incidence of hypertension (1 race: HR, 0.63 [95% CI, 0.62-0.65]; >5 races: HR, 0.51 [95% CI, 0.50-0.53]). A subanalysis of 10 804 participants including adjustment for lifestyle factors showed similar results.Conclusions: Participation in a long-distance skiing event was associated with a 41% lower incidence of hypertension over the next 8 years compared with nonparticipation. A near linear association between performance and incidence of hypertension was observed. This adds to the list of beneficial effects of intensive training, because hypertension is the leading risk factor of premature death globally. [ABSTRACT FROM AUTHOR]

It has been previously observed that athletes of certain origin nationality dominate particular sports; however, this phenomenon has been less studied in cross-country (XC) skiing, especially with regards to performance-related aspects, such as pacing. The aim of the present study was to examine the effect of nationality on pacing strategies of XC skiers who finished the "Vasaloppet" from 2004 to 2017. We studied 183,919 finishers (19,465 women and 164,454 men), classified into 15 nationalities, i.e. nationalities with number of finishers larger than 0.25% of the total number of finishers. In women, athletes from Russia (7:47:46 h:min:s) were the fastest and athletes from Denmark (10:01:03 h:min:s) the slowest (p < 0.001, η2 = 0.057). In men, athletes from Russia (6:33:03 h:min:s) were the fastest and athletes from Denmark (9:03:27 h:min:s) the slowest (p < 0.001, η2 = 0.069). In women and men, a small nationality× split interaction on speed was observed (p < 0.001, η2 = 0.016–0.019) with Russians presenting a more even pacing compared to their slower counterparts. It was concluded that fast nationalities present a more even pacing, which should be attributed to the general trend of fast athletes for a more even pacing. [ABSTRACT FROM AUTHOR]

The aim of the present study was to examine the performance× age interaction on pacing in cross-country (XC) skiing. We analyzed all finishers (n = 79,722) who competed in "Vasaloppet" from 2012 to 2017 grouped in performance quartiles according to their race time with Q1 as the fastest and Q4 as the slowest. Women (44.1 ± 10.2%) had larger pace range than men (40.9 ± 11.8%; p < 0.001, η2 = 0.014). The pace range ranged from 29.8 ± 7.1% (Q1) to 49.0 ± 10.1% (Q4; p < 0.001, η2 = 0.179). In women and men, smaller differences in pace range among age groups for the faster performance groups were observed (p < 0.001, η2 = 0.014, η2 = 0.008, respectively). In summary, fast XC skiers adopted relatively even pacing independent of their age, and the older XC skiers adopted more even pacing than their younger counterparts of similar performance level suggesting that differences among age groups are performance-dependent. [ABSTRACT FROM AUTHOR]

Context: Our understanding of the injury burden in elite adolescent athletes in most sports is limited or unknown because of the lack of prospective, long-term injury studies. Objective: To describe injury patterns in terms of type, location, prevalence and incidence, recurrence and severity grade; time to first injury and prevalence of illness in elite adolescent athletes and to compare differences in injury data by sex and sport type. Design: Cohort study. Setting: Fifteen national sports high schools in Sweden. Patients or Other Participants: Participants were 284 elite adolescent athletes (boys = 147, girls = 137; median age = 17 years; 25th-75th percentile range = 16-18 years) competing at a high national level for their age in athletics (track and field), cross-country skiing, downhill skiing, freestyle skiing, handball, orienteering, or ski orienteering. Main Outcome Measure(s): All athletes were monitored weekly over 52 weeks, using a validated online questionnaire to identify injury type, location, prevalence or incidence and severity grade; time to first injury and prevalence of illness. Results: Among all athletes, 57.4% reported at least 1 new injury, whereas the 1-year injury prevalence was 91.6%. The overall injury incidence was 4.1/1000 hours of exposure to sport, and every week, on average, 3 of 10 (30.8%) elite adolescent athletes reported being injured. Of all injuries from which athletes recovered, 22.2% (n = 35) resulted in absence from normal training for at least 2 months. Female athletes reported higher (P < .05) average weekly injury prevalence and substantial injury prevalence (injuries leading to a moderate or severe reduction in sport performance or participation or time loss) than male athletes. Conclusions: A considerable number of elite adolescent athletes were injured weekly, resulting in serious consequences for sport participation, training, or performance (or a combination of these). Appropriately designed interventions to prevent knee and foot injuries will target both the greatest number of injuries and the injuries with the most serious consequences in elite adolescent athletes. [ABSTRACT FROM AUTHOR]

The objective of the study was to compare the prevalence of self‐reported physician‐diagnosed asthma and age at asthma onset between Swedish adolescent elite skiers and a reference group and to assess risk factors associated with asthma. Postal questionnaires were sent to 253 pupils at the Swedish National Elite Sport Schools for cross‐country skiing, biathlon, and ski‐orienteering (“skiers”) and a random sample of 500 adolescents aged 16‐20, matched for sport school municipalities (“reference”). The response rate was 96% among the skiers and 48% in the reference group. The proportion of participants with self‐reported physician‐diagnosed asthma was higher among skiers than in the reference group (27 vs 19%, P=.046). Female skiers reported a higher prevalence of physician‐diagnosed asthma compared to male skiers (34 vs 20%, P=.021). The median age at asthma onset was higher among skiers (12.0 vs 8.0 years; P<.001). Female sex, family history of asthma, nasal allergy, and being a skier were risk factors associated with self‐reported physician‐diagnosed asthma. Swedish adolescent elite cross‐country skiers have a higher asthma prevalence and later age at asthma onset compared to a reference population. Being an adolescent, elite skier is an independent risk factor associated with asthma. [ABSTRACT FROM AUTHOR]

Background: Prospective injury registration studies, monitoring adolescent elite athletes, are sparse in running, orienteering and cross-country skiing, yet essential for developing prevention programs. Purpose: The aims of this study were to describe the injury prevalence/incidence, severity grade, injury location, risk factors and the prevalence of illness in running (RU), orienteering (OR) and cross-country skiing athletes (CR). Study Design: Prospective cohort study. Methods: One hundred fifty adolescent elite athletes (age range 16-19), participating in orienteering (25 females, 20 males), running (13 females, 18 males), cross-country skiing (38 females, 36 males), from 12 National Sports High Schools in Sweden, were prospectively followed over one calendar year using a reliable and validated web-based questionnaire. Results: The main finding was that the average weekly injury prevalence was higher during the pre-season compared to the competitive season in all three sports. RU reported the significantly (p<0.05) highest average weekly injury prevalence (32.4%) and substantial injury prevalence (17.0%), compared to OR (26.0, 8.2%) and CR (21.1%, 8.9%). Most injuries occurred in the lower extremity (RU 94.4%; OR 91.9%; CR 49.9%) and foot and knee injuries had the highest severity grade in all three sports. History of serious injury (p = 0.002, OR 4.0, 95% CI 1.6-9.7) and current injury at study start (p = 0.004, OR 4.0, 95% CI 1.5-11.2) were identified as the strongest risk factors for substantial injury. Younger athletes aged 16 (p = 0.019, OR 2.6, 95% CI 1.2-5.8) and 17 (p = 0.045, OR 2.4, 95% CI 1.0-5.9), had a significantly higher injury risk for substantial injury compared to older athletes aged 18-19. Conclusion: Practitioners should be aware of the increased injury risk during pre-season and in younger athletes. By focus on prevention of foot and knee injuries, the injuries with the highest severity grade will be targeted in adolescent elite athletes participating in running, orienteering and cross-country skiing. Level of evidence: 2b [ABSTRACT FROM AUTHOR]

To improve current understanding of energy contributions and determinants of sprint-skiing performance, 11 well-trained male cross-country skiers were tested in the laboratory for VO2max, submaximal gross efficiency ( GE), maximal roller skiing velocity, and sprint time-trial ( STT) performance. The STT was repeated four times on a 1300-m simulated sprint course including three flat (1°) double poling ( DP) sections interspersed with two uphill (7°) diagonal stride ( DS) sections. Treadmill velocity and VO2 were monitored continuously during the four STTs and data were averaged. Supramaximal GE during the STT was predicted from the submaximal relationships for GE against velocity and incline, allowing computation of metabolic rate and O2 deficit. The skiers completed the STT in 232 ± 10 s (distributed as 55 ± 3% DP and 45 ± 3% DS) with a mean power output of 324 ± 26 W. The anaerobic energy contribution was 18 ± 5%, with an accumulated O2 deficit of 45 ± 13 mL/kg. Block-wise multiple regression revealed that VO2, O2 deficit, and GE explained 30%, 15%, and 53% of the variance in STT time, respectively (all P < 0.05). This novel GE-based method of estimating the O2 deficit in simulated sprint-skiing has demonstrated an anaerobic energy contribution of 18%, with GE being the strongest predictor of performance. [ABSTRACT FROM AUTHOR]

We studied the association between taking part in a long distance ski race and cancer incidence to address the hypothesis that a lifestyle involving a high degree of physical activity (PA) lowers cancer incidence with a pattern that is different by cancer site. Cancer incidence was estimated in a large cohort of skiers (n = 185,412) participating in the Vasaloppet long distance ski race in Sweden 1989–2010 and non-participants in the ski race, randomly selected from the Swedish general population (n = 184,617). Data include race finishing times as a measurement of physical fitness. Hazard ratios (HRs) and net probability of cancer over twenty years of follow-up were estimated for all invasive cancer, and separately for prostate, breast, colo-rectal and lung cancer, and groups of cancers with presumed relation to lifestyle. Participating in Vasaloppet was associated with a relative risk reduction for all invasive cancer of 6% (95% confidence interval 2–9%) and a relative risk reduction of 32% (95% confidence interval 28–37%) of cancer sites where there is epidemiological evidence that smoking, bodyweight, regular PA and consumption of fruit and vegetables are aetiological factors. For skin cancer the risk was increased, as for prostate cancer. Skiers with shorter finishing times had lower incidence of cancer. This study indicates that it is unrealistic to reduce overall population cancer incidence drastically with life style. However, cancers that are epidemiologically associated with life style factors were significantly reduced by what presumably is a blend of non-smoking, normal body weight, sound dietary habits and PA. Our data thus provide additional support for present days' recommendations about life style prevention. Higher health awareness is associated with attendance to screening, which may explain our results for prostate cancer. University fund, independent funds from an insurance company and a private foundation. [ABSTRACT FROM AUTHOR]

PURPOSE: This study aimed to assess the effect of carrying a rifle on the physiological and biomechanical responses of well-trained biathletes. METHODS: Ten elite biathletes (five men and five women) performed ski skating with (R) or without a rifle (NR) on a treadmill using the V2 (5° incline) and V1 techniques (8°) at 8 and 6 km•h-1, respectively, as well as at racing intensity (approximately 95% of peak oxygen uptake (VO2peak), 10.7 ± 0.8 and 7.7 ± 0.9 km•h-1, respectively). VO2, ventilation (V˙E), HR, blood lactate concentration (BLa), and cycle characteristics as well as pole and leg kinetics were evaluated during these trials. RESULTS: Metabolic data were all higher for R than for NR, as follows: VO2, +2.5%; VE, +8.1%; RER, +4.2%; all P < 0.001; HR, +1.7%; and BLa, +15.1%; both P < 0.05. Biomechanically, carrying a rifle reduced cycle time and length, poling and arm swing times, and leg ground contact time and increased cycle rate, the peak and impulse of leg force, average cycle force, and impulse of forefoot force (all P < 0.05). With the exception of elevated pole forces when V2 skating at racing velocity, there were no differences between the peak and impulse of pole force. The difference in VE between R and NR was greater for the women than that for men (P < 0.05), and the difference in BLa also tended to be larger for the women (P < 0.1). CONCLUSIONS: Carrying a rifle elevated physiological responses, accelerated cycle rate, and involved greater leg work, with no differences between the V1 and V2 techniques. [ABSTRACT FROM AUTHOR]

Cycle and force characteristics were examined in 11 elite male cross-country skiers using the diagonal stride technique while skiing uphill (7.5°) on snow at moderate (3.5 ± 0.3 m/s), high (4.5 ± 0.4 m/s), and maximal (5.6 ± 0.6 m/s) velocities. Video analysis (50 Hz) was combined with plantar (leg) force (100 Hz), pole force (1,500 Hz), and photocell measurements. Both cycle rate and cycle length increased from moderate to high velocity, while cycle rate increased and cycle length decreased at maximal compared to high velocity. The kick time decreased 26% from moderate to maximal velocity, reaching 0.14 s at maximal. The relative kick and gliding times were only altered at maximal velocity, where these were longer and shorter, respectively. The rate of force development increased with higher velocity. At maximal velocity, sprint-specialists were 14% faster than distance-specialists due to greater cycle rate, peak leg force, and rate of leg force development. In conclusion, large peak leg forces were applied rapidly across all velocities and the shorter relative gliding and longer relative kick phases at maximal velocity allow maintenance of kick duration for force generation. These results emphasise the importance of rapid leg force generation in diagonal skiing. [ABSTRACT FROM PUBLISHER]

The aim of this study was to assess potential changes in the performance and cardiorespiratory responses of elite cross-country skiers following transition from the classic (CL) to the skating (SK) technique during a simulated skiathlon. Eight elite male skiers performed two 6 km (2 × 3 km) roller-skiing time trials on a treadmill at racing speed: one starting with the classic and switching to the skating technique (CL1-SK2) and another employing the skating technique throughout (SK1-SK2), with continuous monitoring of gas exchanges, heart rates, and kinematics (video). The overall performance times in the CL1-SK2 (21:12 ± 1:24) and SK1-SK2 (20:48 ± 2:00) trials were similar, and during the second section of each performance times and overall cardiopulmonary responses were also comparable. However, in comparison with SK1-SK2, the CL1-SK2 trial involved significantly higher increases in minute ventilation ( V̇E, 89.8 ± 26.8 vs. 106.8 ± 17.6 L·min−1) and oxygen uptake ( V̇O2; 3.1 ± 0.8 vs 3.5 ± 0.5 L·min−1) 2 min after the transition as well as longer time constants for V̇E, V̇O2, and heart rate during the first 3 min after the transition. This higher cardiopulmonary exertion was associated with ∼3% faster cycle rates. In conclusion, overall performance during the 2 time trials did not differ. The similar performance times during the second sections were achieved with comparable mean cardiopulmonary responses. However, the observation that during the initial 3-min post-transition following classic skiing cardiopulmonary responses and cycle rates were slightly higher supports the conclusion that an initial section of classic skiing exerts an impact on performance during a subsequent section of skate skiing. [ABSTRACT FROM AUTHOR]

The purpose of this study was to: 1) establish the optimal body-mass exponent for maximal oxygen uptake (O2max) to indicate performance in elite-standard men cross-country skiers; and 2) evaluate the influence of course inclination on the body-mass exponent. Twelve elite-standard men skiers completed an incremental treadmill roller-skiing test to determineO2max and performance data came from the 2008 Swedish National Championship 15-km classic-technique race. Log-transformation of power-function models was used to predict skiing speeds. The optimal models were found to be: Race speed = 7.86 ·O2max ·m−0.48and Section speed = 5.96 ·O2max ·m−(0.38 + 0.03 · α)· e−0.003 · Δ(wheremis body mass, α is the section’s inclination and Δ is the altitude difference of the previous section), that explained 68% and 84% of the variance in skiing speed, respectively. A body-mass exponent of 0.48 (95% confidence interval: 0.19 to 0.77) best describedO2max as an indicator of performance in elite-standard men skiers. The confidence interval did not support the use of either “1” (simple ratio-standard scaled) or “0” (absolute expression) as body-mass exponents for expressingO2max as an indicator of performance. Moreover, results suggest that course inclination increases the body-mass exponent forO2max. [ABSTRACT FROM PUBLISHER]

The oldest pairs of skis date from 2500 B.C, they were found in a swamp in current Sweden, which were used for transportation, hunting and food gathering (Street, 1992). However, over the years, ski touring has changed from a tool to survive to a sport that is done by many outdoor recreationists. In Austria alone, there are already 700.000 tour skiers. For a sport that is so popular and has been practiced for centuries, very little research has been conducted on ski touring maps. The state-of-the-art ski touring maps vary in quality. Some map styles do not allow tour skiers to orient themselves in alpine terrain and make it difficult for tour skiers to take impromptu decisions on navigation and avalanche risks. This research created a new user-centered map style for paper ski touring maps using open data, by combining the ongoing research on cartographic techniques and design principles with research on state-of-the-art ski touring maps and interviews with ski touring experts. This is split up into three research objectives. The first objective is to understand the needs and demands of tour skiers for tour skiing maps. The second one is to establish the user-centered map style, solely using open data. At last, the new map design is evaluated and tested by users, in terms of spatial understanding. The methodology of this research is based on the user-centered design process of Roth, Ross, and MacEachren (2015), called the Three U's of Interface Success. The novelty of this research is the design of a ski touring maps. This will not only fill the niche market of ski touring maps, but will also be an inspiration for other cartographers with a step-to-step research on user-centered cartographic design. [ABSTRACT FROM AUTHOR]

Recent developments in cross-country ski racing should promote the use of kick double poling. This technique, however, has not been the focus in athletes' training and has barely been investigated. The aims of the present study were to develop a function-based phase definition and to analyse speed adaptation mechanisms for kick double poling in elite cross-country skiers. Joint kinematics and pole/plantar forces were recorded in 10 athletes while performing kick double poling at three submaximal roller skiing speeds. A speed increase was associated with increases in cycle length and rate, while absolute poling and leg push-off durations shortened. Despite maintained impulses of force, the peak and average pole/leg forces increased. During double poling and leg push-off, ranges of motion of elbow flexion and extension increased (p < 0.05) and were maintained for hip/knee flexion and extension. Cycle length increase was correlated to increases in average poling force (r = 0.71) and arm swing time (r = 0.88; bothp < 0.05). The main speed adaptation was achieved by changes in double poling technique; however, leg push-off showed high variability among elite skiers, thus illustrating important aspects for technique training. [ABSTRACT FROM PUBLISHER]

The article discusses research which was conducted to compare skiing economy and efficiency in recreational and elite cross-country skiers. Researchers evaluated skiers who performed roller skiing on a treadmill. They found that the elite cross country skiers had better skiing economy and higher gross efficiency than the recreational skiers and that the senior elite had better economy and higher efficiency than their junior counterparts.

The purpose of the present study was to establish the most appropriate allometric model to predict mean skiing speed during a double-poling roller skiing time-trial using scaling of upper-body power output. Forty-five Swedish junior cross-country skiers (27 men and 18 women) of national and international standard were examined. The skiers, who had a body mass (m) of 69.3 ± 8.0 kg (mean ± s), completed a 120-s double-poling test on a ski ergometer to determine their mean upper-body power output (W). Performance data were subsequently obtained from a 2-km time-trial, using the double-poling technique, to establish mean roller skiing speed. A proportional allometric model was used to predict skiing speed. The optimal model was found to be: Skiing speed = 1.057 ·W 0.556·m−0.315, which explained 58.8% of the variance in mean skiing speed (P < 0.001). The 95% confidence intervals for the scaling factors ranged from 0.391 to 0.721 forWand from −0.626 to −0.004 form. The results in this study suggest that allometric scaling of upper-body power output is preferable for the prediction of performance of junior cross-country skiers rather than absolute expression or simple ratio-standard scaling of upper-body power output. [ABSTRACT FROM PUBLISHER]

The article discusses research which was conducted to investigate the relationship between body composition and performance in adolescent cross country and alpine skiers. Researchers evaluated 145 male and female adolescent skiers. They found that body composition, including bone mineral density, body fat and lean mass, is associated with physical performance in male and female adolescent skiers.

The article reports on research conducted to establish which physiological test parameters reflects the distance performances in the Swedish National Championships in cross-country skiing. Researchers evaluated 12 elite male skiers. They found that the physiological demands in skiing performances are different in different events and that to evaluate a skier's performance ability it is necessary to use test parameters which reflect specific performance.

The objective was to examine the differences in anxiety ratings of elite and sub-elite athletes when the relationship between intensity and direction scores of anxiety ratings is considered in analyses. Participants were 31 junior elite (Mean age: 17.7, SD=1.1) and 53 sub-elite (Mean age: 17.5, SD=1.1) cross country skiers and swimmers who completed the direction modified CSAI-2R before important competitions. Results showed that elite athletes rated a higher percent of items as facilitative to their performance whereas sub-elite athletes rated a higher percent of items as debilitative. No significant differences between the elite and sub-elite samples were displayed regarding rated direction scores of cognitive or somatic anxiety at moderate to high-intensity levels. A significant difference in facilitative anxiety ratings was displayed at a low anxiety intensity level ( Z=−2.20, P<0.05). Outcome performance data showed no consistent congruence with athletes' anxiety direction ratings. The findings suggest that facilitative direction scores are a consequence of low anxiety intensity, possibly combined with high self-confidence levels. Directional anxiety researchers analyzing separate total scores of intensity and direction respectively, which is the traditional approach, may draw incorrect conclusions about the importance of facilitative ratings of anxiety symptoms. [ABSTRACT FROM AUTHOR]

Objective: The prevalence of asthma among elite endurance athletes is high, but less is known about the incidence of asthma among athletes. The aim of this study was to examine the incidence rate of physician-diagnosed asthma among elite endurance athletes. Method: An annual postal questionnaire was sent to an open prospective cohort of elite endurance athletes between 2011 and 2015. Athletes from Swedish National teams, students at universities with elite sport partnership, and pupils at Swedish National elite sport schools, competing in cross-country skiing, biathlon, ski orienteering, or orienteering were invited ( n  = 666). Incidence rate of physician-diagnosed asthma was calculated among those without asthma at baseline ( n  = 449). Risk factors for incident physician-diagnosed asthma were identified using a multivariate logistic regression analysis. Results: Response rate was 88.7% ( n  = 591) at baseline. The median age of participants was 17 (range 15-36) years at inclusion. The study population included 407 (69%) skiers and 184 (31%) orienteers. The prevalence of asthma at baseline was 23.9% ( n  = 141). Incidence rate (95% confidence interval [CI]) of physician-diagnosed asthma was 61.2 (45.7-80.3) per 1,000 person-years. Risk factors (odds ratio [OR (95% CI)]) for incident physician-diagnosed asthma were family history of asthma (1.97 [1.04-3.68]), being a skier (3.01 [1.42-7.21]), and wheezing without having a cold (4.15 [1.81-9.26]). Conclusion: The incidence rate of physician-diagnosed asthma is high among Swedish elite endurance athletes.

The article discusses the world's longest 90 kilometres cross country ski run known as Vasalopp, scheduled on March 3, 2013, commemorating the 20(th) World Council of Enterostomal Therapists (WCET) 2014 Biennial Congress.

Background: Physical activity is of benefit for primary prevention of cardiovascular diseases, but it appears to increase the risk for atrial fibrillation. We aimed to study a cohort of patients following a first stroke in individuals with previous high physical activity, compare them to the general population with respect to recurrent stroke and death, and relate these to atrial fibrillation., Methods and Results: From the participants of the Vasaloppet, the world's largest ski-race, and matched individuals from the general population (n=708,604), we identified 5964 patients hospitalized with a first-time stroke between 1994 and 2010. Individuals with severe diseases were excluded. One half percent of skiers and 1% of nonskiers were hospitalized due to stroke. The incidence rate was 8.3 per 100 person-years among skiers and 11.1 among nonskiers. The hazard ratio (HR) for recurrent stroke or death between the 2 groups was 0.76 (95% CI 0.67 to 0.86). The result was consistent in subgroups. The HR for death was 0.66 (95% CI 0.56 to 0.78) and for recurrent stroke 0.82 (95% CI 0.70 to 0.96). After adjustment for smoking and socioeconomic factors, the HR for death was consistent at 0.70 (95% CI 0.56 to 0.87) while the HR for recurrent stroke was not statistically significant. Outcomes for skiers with atrial fibrillation tended to show a lower risk than for nonskiers., Conclusions: This large cohort study supports the hypothesis that patients with a stroke and with prior regular physical activity have a lower risk of death, while their risk for recurrent stroke is similar to that of nonskiers. The skiers had a higher incidence of atrial fibrillation, but still no increased risk of recurring stroke., (© 2015 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.)

This study sought to ascertain how multi-dimensional coordination patterns changed with five poling speeds for 12 National Standard cross-country skiers during roller skiing on a treadmill. Self-organizing maps (SOMs), a type of artificial neural network, were used to map the multi-dimensional time series data on to a two-dimensional output grid. The trajectories of the best-matching nodes of the output were then used as a collective variable to train a second SOM to produce attractor diagrams and attractor surfaces to study coordination stability. Although four skiers had uni-modal basins of attraction that evolved gradually with changing speed, the other eight had two or three basins of attraction as poling speed changed. Two skiers showed bi-modal basins of attraction at some speeds, an example of degeneracy. What was most clearly evident was that different skiers showed different coordination dynamics for this skill as poling speed changed: inter-skier variability was the rule rather than an exception. The SOM analysis showed that coordination was much more variable in response to changing speeds compared to outcome variables such as poling frequency and cycle length., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Aims: We aimed to investigate the association of number of completed races and finishing time with risk of arrhythmias among participants of Vasaloppet, a 90 km cross-country skiing event., Methods and Results: All the participants without cardiovascular disease who completed Vasaloppet during 1989-98 were followed through national registries until December 2005. Primary outcome was hospitalization for any arrhythmia and secondary outcomes were atrial fibrillation/flutter (AF), bradyarrhythmias, other supraventricular tachycardias (SVT), and ventricular tachycardia/ventricular fibrillation/cardiac arrest (VT/VF/CA). Among 52 755 participants, 919 experienced arrhythmia during follow-up. Adjusting for age, education, and occupational status, those who completed the highest number of races during the period had higher risk of any arrhythmias [hazard ratio (HR)1.30; 95% CI 1.08-1.58; for ≥5 vs. 1 completed race], AF (HR 1.29; 95% CI 1.04-1.61), and bradyarrhythmias (HR 2.10; 95% CI 1.28-3.47). Those who had the fastest relative finishing time also had higher risk of any arrhythmias (HR 1.30; 95% CI 1.04-1.62; for 100-160% vs. >240% of winning time), AF (1.20; 95% CI 0.93-1.55), and bradyarrhythmias (HR 1.85; 95% CI 0.97-3.54). SVT or VT/VF/CA was not associated with finishing time or number of completed races., Conclusions: Among male participants of a 90 km cross-country skiing event, a faster finishing time and a high number of completed races were associated with higher risk of arrhythmias. This was mainly driven by a higher incidence of AF and bradyarrhythmias. No association with SVT or VT/VF/CA was found.