Female Cross-country Skiers Research Articles

Annual Volume and Distribution of Physical Training in Norwegian Female Cross-Country Skiers and Biathletes: A Comparison Between Sports, Competition Levels, and Age Categories-The FENDURA Project.

To describe and compare the annual physical training characteristics between Norwegian female cross-country (XC) skiers and biathletes across competition levels and age categories. Daily training sessions for 1year were recorded for 45 XC skiers and 26 biathletes, comprising international/national team (inter[national]) and nonnational/regional team members (nonnational) of both junior and senior age. Endurance, strength, flexibility, speed, and power training sessions were recorded. Data included exercise modality, intensity, and duration. Data were analyzed using linear mixed-effects models. The total annual physical training volume consisted of ∼90% endurance training for both groups, although XC skiers had significantly higher total volumes (∼10%; P = .003; d = 0.78) than biathletes. Senior XC skiers performed more training hours of skiing and/or roller skiing compared with biathletes over the season. However, biathletes compensated for this lower volume by more skating and a higher proportion of endurance training as skiing (81% [17%]) compared with XC skiers (68% [16%]; P < .001; d = 0.94). Overall, (inter)national-level athletes completed a higher annual training volume than non-national-level athletes (740 [90]h vs 649 [95]h; P = .004;d = 0.81). Although juniors reported less endurance volume than seniors, they maintained a relatively stable level of endurance training across the preparatory and competition period, unlike senior athletes. The higher annual physical training volume by XC skiers compared with biathletes is likely caused by the different demands of the 2 sports; XC skiing necessitates training for 2 skiing styles, while biathlon requires additional shooting practice. However, biathletes compensate with a higher proportion of ski training, particularly in the skating technique.

Tick-Tock Goes the Biological Clock: Challenges Facing Elite Scandinavian Mother-Athletes

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.

Response of cardiorespiratory system during maximal exercise cycle ergometer test in women cross-country skiers with different skills levels

Objective: to estimate the functional features of the cardiorespiratory system of female cross-country skiers with different skills levels at the maximal bicycle ergometer test.Material and methods: 70 female cross-country skiers were divided into three groups. The first group included 21 cross-country skiers with first adult sporting rank, the second — 25 candidates in master of sports, the third group — 24 sport masters in cross-country skiing. Maximal exercise tests were used to determine cardiorespiratory fitness via spiroergometric system «Oxycon Pro» (Jaeger, Hoechberg, Germany).Results: The most notable differences were observed between the first-class and the masters of the sports groups. In the first-class group the heart rate during the maximal exercise test was, on average, 11 beats/min higher than in the master of sports group (p&lt;0.05), and the oxygen consumption at the anaerobic threshold was, on average, lower by 7.7 ml/min/kg (p &lt; 0.05) when comparing the same groups.Conclusion: The influence of skills levels on physiological parameters at maximal bicycle ergometer test was shown. The capacity in the first group occurs due to cardiovascular system tension, and the same in the group high qualification skiers happen due to the mechanisms of oxygen transport development.

Carbohydrate intake in young female cross-country skiers is lower than recommended and affects competition performance.

(1) To evaluate if energy availability (EA), macronutrient intake and body composition change over four training periods in young, highly trained, female cross-country skiers, and (2) to clarify if EA, macronutrient intake, body composition, and competition performance are associated with each other in this cohort. During a one-year observational study, 25 female skiers completed 3-day food and training logs during four training periods: preparation, specific preparation, competition, and transition periods. A body composition measurement (bioimpedance analyzer) was performed at the end of the preparation, specific preparation, and competition periods. Competition performance was determined by International Ski Federation (FIS) points gathered from youth national championships. EA (36-40 kcal·kg FFM-1·d-1) and carbohydrate (CHO) intake (4.4-5.1 g·kg-1·d-1) remained similar, and at a suboptimal level, between training periods despite a decrease in exercise energy expenditure (p = 0.002) in the transition period. Higher EA (r = -0.47, p = 0.035) and CHO intake (r = -0.65, p = 0.002) as well as lower FM (r = 0.60, p = 0.006) and F% (r = 0.57, p = 0.011) were associated with lower (better) FIS-points. CHO intake was the best predictor of distance competition performance (R2 = 0.46, p = 0.004). Young female cross-country skiers had similar EA and CHO intake over four training periods. Both EA and CHO intake were at suboptimal levels for performance and recovery. CHO intake and body composition are important factors influencing competition performance in young female cross-country skiers.

Exercise and prevalence of cardiovascular disease in older female endurance athletes during 10 years follow-up

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): PhD student Kristoffer Johansen is funded by the Northern Norway Regional Health Authority (grant number HNF1568-21). The Birkebeiner Ageing Study has been funded by the Kavli research center for ageing and dementia and the Norwegian ExtraFoundation. Background Although research suggests that the health benefits of endurance sport practice is larger in female compared to male athletes, women are underrepresented in sports cardiology research. Furthermore, previous studies on endurance sport practice in women have mostly included younger to middle aged athletes. Thus, prospective studies addressing endurance sport practice and health among older female endurance athletes is lacking. Purpose The purpose of this study was to characterise how older recreational female cross-country skiers maintained exercise and cardiovascular health during 10-years follow up. Method Forty-six women aged ≥65 years that completed the 54-km Birkebeiner cross country ski race in Norway in 2009/2010 were included. The Birkebeiner race includes about 1000 uphill altitude meters and is considered one of the world's most challenging ski races. Participants answered a questionnaire addressing exercise habits and health issues at baseline in 2009/10 and at follow-up in 2014 and 2020. Thirty-five (76%) participants attended follow-up in 2014 and 36 (78%) participants attended follow-up in 2020. Descriptive statistics are given as mean ± SD for continuous variables and as percentages for categorical variables. Results Skiers (age 67.5 ± 2.2 years at baseline) reported a cumulative exposure to regular endurance exercise of 26 ± 15 years. The proportion reporting moderate- to vigorous exercise during the past year was 86% at baseline and 61% at follow-up in 2020. One woman died during follow up. During 10-years follow-up the cumulative prevalence of atrial fibrillation (AF) was 15.6%, more than twice as high as for other cardiac diseases (7.1%) and stroke (7.1%). Conclusion Most female athletes sustained a physically active and healthy lifestyle with advancing age. Notably, the prevalence of AF was twice as high as for other cardiac diseases and stroke. Thus, although previous literature indicates that the risk of AF in female athletes is reduced, our findings suggest that additional research is needed to draw more firm conclusions. Future studies aiming to further clarify the female athlete and AF association would greatly benefit from including older athletes that has accumulated several decades of endurance sport practice. In conclusion, further research aiming to close the knowledge gap between female and male athletes are highly warranted.

Physiological profiles and training loads of international level male and female cross-country skiers and biathletes

The aim was to investigate physiological profiles of elite male and female cross-country skiers and biathletes in the context of their annual training load volumes and whether this explained differences in racing speeds. 108 Russian athletes (International rank: 2–211) were divided into four groups (cross-country skiers and biathletes, males and females), matched for age. Fitness assessment included 33 anthropometrics, aerobic, anaerobic, strength, and gross-efficiency of upper-body and lower-body parameters. Training load volumes included 21 endurance, strength, power, sport-specific, and non-specific parameters averaged over 2014–2020. Cross-country skiers significantly exceeded biathletes in strength (X ± SD: 81 ± 12 vs 45 ± 12 hours, P < 0.001) and endurance training load volumes (779 ± 42 vs 547 ± 40 hours, P < 0.001). Cross-country skiers had higher: body mass index (23.0 ± 3.3 vs 22.4 ± 1.8, kg/m 2 , P = 0.008); upper-body and running ventilation thresholds (50.1 ± 7.9 vs 46.2 ± 5.4, and 62.5 ± 4.0 vs 60.5 ± 6.7 mL/min/kg, P < 0.001), but equal V̇O 2 max and gross-efficiency. Male and female athletes had equal volumes of endurance and strength training loads, but females tended to have lower values of training intensity. Gender upper-body and lower-body differences were greater for aerobic and anaerobic power but smaller for strength. L’objectif de cette étude était d’explorer les profils physiologiques des skieurs de fond et biathlètes élite hommes et femmes en relation avec leur charge d’entraînement annuelle et de déterminer les paramètres permettant d’expliquer des différences dans les vitesses de course. 108 athlètes russes (2 à 211 dans le classement mondial) ont été répartis en 4 groupes (skieurs de fond et biathlètes, hommes et femmes), pondérés par l’âge moyen par groupe. L’évaluation de la condition physique incluait 33 paramètres du haut et du bas de corps comprenant des données anthropométriques, d’aérobie, d’anaérobie, de force et des coefficients d’efficacité de travail musculaire. La charge d’entraînement, établie sur une moyenne de 2014 à 2020, incluait 21 paramètres comprenant des données relatives à l’endurance, la force, la puissance, spécifiques ou non au sport pratiqué. Les skieurs de fond avaient des volumes d’entraînement en force (X ± : 81 ± 12 vs 45 ± 12 heures, p < 0,001) et en endurance (779 ± 42 vs 547 ± 40 heures, p < 0,001) supérieurs aux biathlètes.Chez les skieurs de fond l’indice de masse corporelle (23,0 ± 3,3 vs 22,4 ± 1,8, kg/m 2 , p = 0,008), le seuil ventilatoire lors de travail du haut du corps et lors de la course à pied (50,1 ± 7,9 vs 46,2 ± 5,4, and 62,5 ± 4,0 vs 60,5 ± 6,7 mL/min/kg, p < 0,001), étaient supérieurs comparativement aux biathlètes mais le V̇O 2 max et le rendement étaient similaires. Les athlètes masculins et féminins ont eu la même charge d’entrainement en force et en endurance, excepté pour les athlètes féminins qui ont eu la tendance d’avoir moins d’intensité d’entrainement. Les différences liées au genre des paramètres du haut du corps et du bas du corps étaient plus importantes pour la puissance aérobie et anaérobie mais inférieures pour la force.

Prevalence and Self-Perceived Experiences With the Use of Hormonal Contraceptives Among Competitive Female Cross-Country Skiers and Biathletes in Norway: The FENDURA Project.

PurposeTo investigate the prevalence of hormonal contraceptive (HC) use by female cross-country (XC) skiers and biathletes competing at a national and/or international level, their reasons for HC use, and to compare negative symptoms related to the HC-/menstrual cycle in HC users and non-HC users. Additionally, to characterize the self-perceived influence of HC use on training and performance.MethodsA total of 113 Norwegian competitive XC skiers and biathletes completed an online questionnaire including both closed and open-ended questions. The questions were designed to assess the type of HC, reasons for use, self-reported negative symptoms related to HC-/menstrual cycle, as well as athletes' experiences regarding how HC use affects training and performance.ResultsIn total, 68% of all the athletes used HC, with 64 and 36% of them using a progestin-only and combined type HC, respectively. Non-contraceptive reasons for HC use were reported by 51% of the progestin-only HC users vs. 75% of the combined HC users (P = 0.039), with reduction of negative menstrual-related symptoms as the most common reason. Of the athletes reporting regular withdrawal bleedings in connection to HC use, 80% of the progestin-only and 86% of combined HC users experienced negative menstrual-related symptoms, which was comparable to the non-HC group (86%). The majority (81%) of HC users experienced solely positive, or no effect, of HC use on training and performance, with no differences between progestin-only and combined HC users (P = 0.942).ConclusionsIn total, 68% of the XC skiers and biathletes used HC, with the highest proportion (64%) using a progestin-only HC. Many athletes used HC to manipulate their menstrual cycle due to perceived negative menstrual-related symptoms that interfered with their training sessions and/or competitions.

Upper- vs. Lower-Body Exercise Performance in Female and Male Cross-Country Skiers.

Purpose: To investigate the interaction between exercise modality (i.e., upper- and lower-body exercise) and sex in physiological responses and power output (PO) across the entire intensity spectrum (i.e., from low to maximal intensity).Methods: Ten male and 10 female cross-country (XC) skiers performed a stepwise incremental test to exhaustion consisting of 5 min stages with increasing workload employing upper-body poling (UP) and running (RUN) on two separate days. Mixed measures ANOVA were performed to investigate the interactions between exercise modalities (i.e., UP and RUN) and sex in physiological responses and PO across the entire exercise intensity spectrum.Results: The difference between UP and RUN (ΔUP−RUN), was not different in the female compared with the male XC skiers for peak oxygen uptake (18 ± 6 vs. 18 ± 6 mL·kg−1·min−1, p = 0.843) and peak PO (84 ± 18 vs. 91 ± 22 W, p = 0.207). At most given blood lactate and rating of perceived exertion values, ΔUP−RUN was larger in the male compared with the female skiers for oxygen uptake and PO, but these differences disappeared when the responses were expressed as % of the modality-specific peak.Conclusion: Modality-differences (i.e., ΔUP−RUN) in peak physiological responses and PO did not differ between the female and male XC skiers. This indicates that increased focus on upper-body strength and endurance training in female skiers in recent years may have closed the gap between upper- and lower-body endurance capacity compared with male XC skiers. In addition, no sex-related considerations need to be made when using relative physiological responses for intensity regulation within a specific exercise modality.

"Do Elite Sport First, Get Your Period Back Later." Are Barriers to Communication Hindering Female Athletes?

Competitive female athletes perceive their hormonal cycles to affect their training, competition performance and overall well-being. Despite this, athletes rarely discuss hormonal-cycle-related issues with others. The aim of this study was to gain an in-depth understanding of the perceptions and experiences of endurance athletes and their coaches in relation to barriers to athlete–coach communication about female hormonal cycles. Thirteen Swedish national-/international-level female cross-country skiers (age 25.8 ± 3.6 y) and eight of their coaches (two women and six men; age 47.8 ± 7.5 y) completed an online survey relating to their educational background, prior knowledge about female hormonal cycles and a coach–athlete relationship questionnaire (CART-Q). They then participated in an online education session about female hormonal cycles and athletic performance before participating in semi-structured focus-group interviews. Thematic analyses revealed three main barriers to communication: knowledge, interpersonal, and structural. In addition, the results suggested that a good coach–athlete relationship may facilitate open communication about female hormonal cycles, while low levels of knowledge may hinder communication. To overcome the perceived barriers to communication, a model is proposed to improve knowledge, develop interpersonal relationships and strengthen structural systems through educational exchanges and forums for open discussion.

Pole Length Influences Performance During On-Snow Skating in Female Cross-Country Skiers

PurposeThe purpose of this study was to examine the effect of pole length on performance and technique selection during a simulated skating cross-country (XC) skiing competition on snow in female XC skiers.MethodsNine female XC skiers and biathletes (VO2max 63.6 ± 6.2 mL/min/kg, age 22.9 ± 3.5 years, body height 1.69 ± 0.1 m and body mass 60.8 ± 4.6 kg) completed two 5-km skating time-trail with maximal effort. The athletes had a minimum 4.5 h of rest between the two races, which were performed in a random order: one with self-selected poles (89.0% ± 0.6% of body height) and one with 7.5 cm increased pole length (94.0% ± 0.5% of body height). Speed in set terrain sections was determined and the selection of sub-technique was self-reported immediately after each race based on a detailed review of the entire track.ResultsSkiers performed on average 7.1 ± 7.1 s (P = 0.029) faster with the long poles, with this difference occurring during the first 200 m and in the uphill parts of the track, in which ~ 5% more G3 and ~ 5% fewer G2 sub-techniques were chosen (both P < 0.05). The rating of perceived exertion was 1 ± 0.9 point lower (P = 0.04) and skiing technique was perceived to be ~ 1.2 ± 1.5 points better with long poles (P = 0.038), while the physiological responses (i.e., peak and average heart rate, and blood lactate concentration) did not differ between trials.ConclusionIn conclusion, poles 7.5 cm longer than self-selected ones improved performance in skating, by enhancing speed in the initial phase (first 200 m) and in the uphill section of the track. In addition, the longer poles induced more use of the G3 skating sub-technique.

Do exist gender differences in skin temperature of lower limbs following exercise test in male and female cross-country skiers?

The aim of study was to assess the skin temperature changes over selected muscles zones of the lower limbs following an exercise performed at similar relative external workload in 10 male and 6 female high-trained cross-country skiers. The first stage of experiment involved preliminary exercise to determine individual oxygen uptake VO2max and anaerobic threshold. The second stage experimental exercise consisted of 60 min running on treadmill with 80% of determined VO2max Thermographic imaging of lower limbs was performed, before, immediately after exercise and during recovery. Physiological parameters: VO2, MET—metabolic energy equivalent, heart rate and internal temperature were assessed at rest and at the end of exercise, respectively. Infrared thermography showed that at rest the skin temperature over lower limb muscles was significantly higher in men than in women. In response to exercise an increase in skin temperature over the studied muscles was significantly higher in women than men. Since was no significant difference in skin temperature in men and women after exercise. Before the test, no physiological parameter was significantly different in women and men. Exercise test reveled significant differences between men and women in some physiological parameters such as VO2 and MET. Our study showed that there are significant differences in lower limbs skin temperature between male and female at rest but not at the end of exercise test. Women in comparison with men had a greater increase in skin temperature in response to exercise and a persistence of elevated temperature over muscles of lower limbs after exercise.

The Effect of Polarized Training on the Athletic Performance of Male and Female Cross-Country Skiers during the General Preparation Period.

This study aimed to analyze the effect of 12 weeks of polarized training on body composition, cardiorespiratory function, and upper-body power of male and female cross-country skiers during the general preparation period. A total of 16 national cross-country skiers (8 male and 8 female; 8 national cross-country skiers and 8 national biathlon athletes) participated. Polarization training was conducted for 12 weeks from May to July in 2019 during the general preparation period for cross-country skiers. The low-weight, high-repetition method was used for strength training. The effect of the polarized training on body composition, maximum oxygen intake (VO2max), respiratory exchange rate, all-out time, and ski ergometer exercise time was assessed. There was no change in weight, BMI, and muscle mass in male and female cross-country skiers following the 12 weeks of polarized training (p > 0.05). Male body fat percentage (pre 18.1%, post 12.7%) and female body fat percentage (pre 29.1%, post 21.4%) showed a significant decrease (p < 0.05). After training, VO2max increased by 7.72% in male athletes (pre 71.05 mL/kg/min, post 77.0 mL/kg/min) and 6.32% in female athletes (pre 60.26 mL/kg/min, post 64.33 mL/kg/min). Treadmill exercise time increased by 5.39% for male athletes (pre 1038 s, post 1064 s) and 2.23% for female athletes (pre 855 s, post 874 s). However, there was no significant difference between male and female athletes (p > 0.05). The 50% recovery time from the maximum heart rate to the target heart rate decreased by 64.52% in males (pre 168.8 s, post 102.6 s) and 6.48% in females (pre 135 s, post 129.6 s). Significant differences were found only in male athletes (p < 0.05). The double-pole 500 m exercise duration for the ski ergometer significantly decreased after the training for both sexes (p < 0.05). In this study, the 12 weeks of polarized training improved the body composition and athletic performance of all cross-country skiers. Interestingly, in this study, we confirmed that polarized training had a better effect on cardiorespiratory function in male cross-country skiers than in female cross-country skiers. Conversely, we found that the outcomes of the ski ergometer exercise factors were more effective in female athletes than in male athletes. Therefore, we insist that when applying a polarized training program to athletes, it should be planned in detail by sex, exercise amount, intensity, and type of training.

Nutrition Knowledge Is Associated with Energy Availability and Carbohydrate Intake in Young Female Cross-Country Skiers

The aim of this study was to provide information on energy availability (EA), macronutrient intake, nutritional periodization practices, and nutrition knowledge in young female cross-country skiers. A total of 19 skiers filled in weighted food and training logs before and during a training camp. Nutrition knowledge was assessed via a validated questionnaire. EA was optimal in 11% of athletes at home (mean 33.7 ± 9.6 kcal·kgFFM−1·d−1) and in 42% at camp (mean 40.3 ± 17.3 kcal·kgFFM−1·d−1). Most athletes (74%) failed to meet recommendations for carbohydrate intake at home (mean 5.0 ± 1.2 g·kg−1·d−1) and 63% failed to do so at camp (mean 7.1 ± 1.6 g·kg−1·d−1). The lower threshold of the pre-exercise carbohydrate recommendations was met by 58% and 89% of athletes while percentages were 26% and 89% within 1 h after exercise, at home and at camp, respectively. None of the athletes met the recommendations within 4 h after exercise. Nutrition knowledge was associated with EA at home (r = 0.52, p = 0.023), and with daily carbohydrate intake at home (r = 0.62, p = 0.005) and at camp (r = 0.52, p = 0.023). Carbohydrate intake within 1 and 4 h post-exercise at home was associated with better nutrition knowledge (r = 0.65, p = 0.003; r = 0.53, p = 0.019, respectively). In conclusion, young female cross-county skiers had difficulties meeting recommendations for optimal EA and carbohydrate intake. Better nutrition knowledge may help young athletes to meet these recommendations.

Choice of Pole and Ski Lengths Among Elite Cross-Country Skiers: The Influence of Sex and Performance Level.

Cross-country (XC) skiers employ whole-body exercise to generate speed through poles and skis. The choice of optimal pole and ski lengths are therefore of high importance. The aim of this study was to document pole and ski lengths among elite male and female cross-country skiers in the classical and skating styles and to investigate sex differences in body-height-normalized pole and ski lengths. Our secondary purpose was to correlate body-height-normalized pole and ski lengths with performance level within both sexes. In total, Norwegian men and women (n = 87 and 36, respectively), participating in the Norwegian XC championship 2020, were investigated. Most athletes used poles close to the length allowed by the International Ski Federation (FIS) in the classical style among both sexes, with men using slightly longer poles than women (p < 0.05). Body-height-normalized pole lengths in skating were similar in men and women (around 90% of body height). Women used relatively longer ski lengths than men in both styles (p < 0.05). Women showed moderate correlations (r = 0.43, p < 0.05) between body-height-normalized pole lengths and sprint performance. Male and female cross-country skiers use as long classical ski poles as possible within the current regulations, while they use skating poles similar to recommendations given by the industry. The fact that men use longer body-height-normalized poles than women, where there is a correlation between pole length and sprint performance, indicate that faster women are able to better utilize the potential of using longer poles when double-poling. However, while women use relatively longer skis than men, no correlation with performance occurred for any of the sexes.

Comparisons of Macro-Kinematic Strategies During the Rounds of a Cross-Country Skiing Sprint Competition in Classic Technique.

This study was designed to examine macro-kinematic parameters of six female cross-country skiers during the qualifying, semi-final and final rounds of a 1.1 km sprint competition in classical technique. During each round these skiers were monitored continuously with a single micro-sensor, and their cycle parameters and relative use of these two sub-techniques calculated. Within each round six sections of the course, during which all skiers employed either double pole (DP) or diagonal stride (DS) sub-technique, were chosen for additional analysis. The mean macro-kinematic cycle parameters and relative usage of sub-techniques over the full course did not differ significantly between rounds. On average 54% of the course was covered employing DP and 13% using DS, while 32% was covered utilizing a non-cyclical or irregular technique. With DP, the mean racing speed and cycle rate (CR) on the starting, middle and finishing sections of the course differed significantly, with no differences in mean cycle length (CL) between the last two sections. At the finish, higher DP speed was achieved by increasing CR. On the three hills, where all athletes utilized DS, mean racing speed and CL, but not mean CR, differed significantly. On these sections DS speed was increased by utilizing longer cycles. The individual skiers utilized a variety of macro-kinematic strategies during different rounds and on different sections of the course, depending on individual strengths, preferences and pacing strategies, as well as the course topography and tactical interactions with other skiers. Such collection of macro-kinematic data during competitions can help to identify an individual skier's strengths and weaknesses, guiding the testing of different cycle rates, and lengths on different terrains during training in order to optimize performance.

Energy availability during training camp is associated with signs of overreaching and changes in performance in young female cross-country skiers

Abstract Study aim: The aim of this study was to evaluate if young female skiers meet their energy and macronutrient requirements, and how energy availability (EA) and macronutrient intake affects their performance during an intensive training camp. Material and methods: 19 female cross-country skiers (age 16.7 ± 0.7) filled in 48-hour food and training logs during a 5-day training camp. Fasting concentrations of hemoglobin, leptin, triiodothyronine (T3), insulin, insulin-like growth factor 1 (IGF-1), and glucose were measured before (PRE) and after (POST) the camp. Blood lactate (LA), heart rate (HR) and rating of perceived exertion (RPE) from a submaximal treadmill running test, jump height from counter movement jump (CMJ), and power from a reactive jump test (RJ) were also measured PRE and POST. Results: Mean EA was 40.3 ± 17.3 kcal · kgFFM–1 · d–1. 58% of the participants had suboptimal EA, 37% had low EA, and 53% had suboptimal carbohydrate intake. HR, HR/RPE ratio, LA/RPE ratio, CMJ, hemoglobin, leptin, T3, and insulin decreased from PRE to POST. RPE and glucose increased from PRE to POST. EA during the camp correlated with changes in LA (r = 0.54, p = 0.018), LA/RPE (r = 0.65, p = 0.003), and RJ (r = 0.47, p = 0.043). Conclusions: Many athletes had difficulties in meeting their energy and carbohydrate requirements during a training camp. Furthermore, sufficient EA may help to avoid overreaching and to maintain performance during an intensive training period.

Sex-based differences in sub-technique selection during an international classical cross-country skiing competition.

The purpose of this study was to compare speed, sub-technique selection and temporal patterns between world-class male and female cross-country (XC) skiers and to examine the combined associations of sex and speed on sub-technique selection. Thirty-three XC skiers performed an international 10-km (women; n = 8) and 15-km (men; n = 25) time-trial competition in the classical style (with the first 10 km of the race being used for analyses). An integrated GNSS/IMU system was used to continuously track position speed and automatically classify sub-techniques and temporal patterns (i.e. cycle length and–rate). When comparing the eight highest ranked men and women, men spent less time than women (29±2 vs. 45±5% of total time) using diagonal stride (DIA), more time (44±4 vs. 31±4%) using double poling (DP) and more time (23±2 vs. 19±3%) using tucking and turning (all P < .01). Here, men and women used these sub-techniques at similar temporal patterns within the same speed-intervals; although men employed all sub-techniques at steeper uphill gradients (all P < .05). In subsequent analyses including all 33 skiers, adjustment for average racing speed did not fully attenuate the observed sex differences in the proportion of time using DIA (CI95% [-10.7, -1.6]) and DP (CI95% [0.8, 9.3]). Male world-class XC skiers utilized less DIA and more DP compared to women of equal performance levels. Although these differences coincided with men’s higher speed and their ability to use the various sub-techniques at steeper uphill gradients, sexual dimorphism in the proportional use of DIA and DP also occurred independently of these speed-differences.

Constructing a Talent Identification Index System and Evaluation Model for Cross-Country Skiers

ABSTRACT A talent identification index system for male and female cross-country skiers in four age groups (11–12 years old, 13–14 years old, 15–16 years old, and 17–18 years old) was established. The system comprises five body shape indexes (=5): Leg-to-Body Ratio (LBR), body fat percentage, maturity status, spreaded brachia index, and upper extremity length. The physiological function indexes (=2) are VO2max and haemoglobin mass (Hb). The psychological indexes (=5) cover reaction time, perception speed, a quality-of-will scale, an attention test, and operational thinking. The physical fitness indexes (=11) comprise upper limb explosiveness, vertical jump, 3000-metre run, orthostatic forward flexion, closed-eyes single-leg stand, standing long jump, 20-metre sprint, pull-ups (males), flexed arm hang (females), hexagon jump, and a Functional Movement Screen (FMS) test. The athletic performance indexes (=3) comprise on-snow time trials for 1.2 km, 5 km, and 10 km. The talent identification evaluation model was created using automated evaluation software. The talent identification index system and evaluation standard table for cross-country skiers passed the P60 shortlist and P90 elite boundaries established using the percentile method. Thus, the results of this test profile verify that the evaluative model is objectively effective.

The role of incline, speed and work rate on the choice of technique in classical roller skiing.

Cross-country skiers use different sub-techniques like ‘gears’ (diagonals stride, double poling with kick, and double poling) depending on terrain (incline) and demand (speed and external work rate). Previous studies have identified the major effect of speed and incline, but not any potential interaction between these parameters: the incline-speed combination determines the work rate, which in itself may be a controlling factor. The aim of this study was to investigate the role of these task conditions (external work rate, speed, incline) and their interactions on the choice of sub-technique in classical roller skiing. Twelve male and nine female cross-country skiers executed three subsets of protocols in which two of three condition parameters were altered every 15 seconds while roller skiing on a treadmill. This design created a quasi-random set of combinations of speed, incline and work rate that were analysed on sub-technique choice. A repeated measures model with sex as between subject factor was conducted for each subset of protocols. The incline appeared to be the factor affecting sub-technique choice most, but not exclusively; at constant incline, athletes applied different sub-techniques, depending mostly on speed rather than work rate. Most athletes did not use one particular sub-technique for a given speed-incline-work rate combination, but it depended on the protocol and direction of condition change in the constant speed protocol (hysteresis). Only minor differences between men and women existed regarding the impact of condition factor on sub-technique choice. The findings disagree with the notion of a simple mechanism that explains the choice of sub-technique, but rather opt for a complex structure that entangles various mechanisms which play a role in the choice of sub-technique under moderate effort conditions.

Performance and Micro-Pacing Strategies in a Classic Cross-Country Skiing Sprint Race.

The purpose of the present study was to analyze micro-pacing strategies in cross-country skiing, and their relation to section and total race times. Eleven competitive female cross-country skiers were tracked during a classic sprint time-trial race using a global navigation satellite system (GNSS) unit. A coordinate mapping procedure was applied to the GNSS unit measurements to analyze the instantaneous velocities and split times. The track was divided into nine sections and individual section times were calculated. Statistical parametric mapping (SPM) was used to analyze the relationships between instantaneous velocity and section or total race time. SPM analyses revealed two uphill sections and one flat section where greater instantaneous velocities were related to faster total race times. The first major uphill section on the track demonstrated a more conservative micro-pacing strategy (SPM supra-threshold clusters along the entire uphill, p < 0.05–0.001) compared to the more aggressive strategy used in the last uphill section (clusters on the first half of the uphill, p < 0.05–0.001). Faster flat section times were associated with greater instantaneous velocities throughout the section (p < 0.001), while faster downhill section times were related to greater instantaneous velocities at the top of the downhill (p < 0.001), and in the downhill turns (p < 0.001). In conclusion, micro-pacing strategies were related to overall skiing performance and distinct track sections were identified where instantaneous velocities were related to section or total race times. In order to improve skiing performance, athletes could focus on more aggressive pacing early on in the “end spurt”, during the transitions from uphill to flat sections, and during the transitions from flat or uphill to downhill sections.