BackgroundA limited number of long-term prospective studies have investigated health problems in competitive cross-country skiers. Moreover, limited information exists regarding differences in the ...prevalence and severity of health problems between senior and development female and male cross-country skiers.ObjectiveTo compare the prevalence and severity of health problems between senior and development female and male national team cross-country skiers.DesignComparative, prospective, observational cohort study.SettingSenior and development national cross-country ski teams.ParticipantsEighteen (9 women, 9 men) senior and 22 (9 women, 13 men) development national team skiers.InterventionSkiers self-reported their health problems weekly for 17 weeks throughout the 2019/2020 competitive cross-country ski season using the Oslo Sports Trauma Research Center Questionnaire on Health Problems (OSTRC-H2).Main Outcome MeasurementsWe calculated weekly prevalence and severity measures for illnesses, acute and overuse injuries, substantial health problems (i.e., health problems leading to moderate or severe reductions in training volume or sports performance, or a complete inability to participate) and all health problems combined.ResultsWeekly response rate to the OSTRC-H2 was 90% (SD 7%). Average weekly prevalence of substantial (~12%) and all (~25%) health problems were similar between senior and development team skiers. However, illness prevalence was lower in senior vs. development skiers (8%, 95% CI 3%, 13% vs. 13%, 95% CI 9%, 17%, respectively; p = .026) and injuries were higher (12%, 95% CI 9%, 15% vs. 5%, 95% CI 3%, 7%; p < .001). There were no differences in severity measures (all p > .05).ConclusionsHealth problems were relatively common among the skiers, with one quarter affected by at least one problem at any given time. While the prevalence of all health problems was similar, illnesses were less prevalent in the senior compared to the development team skiers and injuries were more prevalent.
BackgroundMetabolomics has potential to highlight novel pathways and biomarkers of interest to provide early warning signs of health problems, such as opportunistic infection susceptibility among ...athletes.ObjectiveTo investigate differences in metabolites at rest and in response to exercise among athletes susceptible and not susceptible to opportunistic infections.DesignProspective cohort study.SettingLaboratory tests and illness diaries from national-team cross-country skiers.ParticipantsThirteen male and ten female, aged 21 ± 1 years.InterventionsCapillary whole blood samples collected at rest and following a maximal incremental exercise test. Metabolite profiles at rest and post-exercise obtained using targeted and untargeted liquid and gas-chromatography analysis.Main Outcome MeasurementsIllness incidence, prospectively monitored for 15 weeks using the OSTRC-H questionnaire. Discriminating metabolites between the two groups at rest and in response to exercise, analysed using OPLS-DA followed by enrichment analysis of metabolic pathways in the KEGG database.ResultsParticipants reporting ≥1 illnesses during the observation period were classified as illness susceptible (n = 14) and those that remained healthy as not susceptible (n = 8). The initial OPLS-DA model including all 346 identified metabolites (at rest) did not reach statistical significance but significance was achieved (R2Y = 0.916, Q2 = 0.617, p = 0.030) when refined to include only metabolites with a variable influence on projection of >1 (n = 129). Glucose-6-phosphate, squalene and deoxycholic acid contributed most to the separation. Enrichment analysis indicated no significant differences in metabolic pathway activity between groups. No significant OPLS-DA model was achieved for metabolite responses to exercise.ConclusionsWhile our models achieved separation between susceptible and non-susceptible athletes using resting metabolic profiles, the primary identified metabolites do not overlap with existing findings in the literature. Further exploration of biomarkers of infection risk using omics approaches in larger and more heterogeneous cohorts may be considered.
Cross‐country skiing causes strain in the airways because skiers train and compete in cold air. The aim of this survey was to investigate the prevalence and age at onset of asthma, asthma control, ...and use of asthma medication in Finnish competitive cross‐country skiers. All cross‐country skiers who were enrolled in the largest national competitions in winter 2019 (n = 1282) were invited to the study via the Finnish Ski Association. A control group (n = 1733) was matched for the responding skiers by age, gender, and region. The response rate was 27.4% (n = 351) for skiers and 19.5% (n = 338) for the controls. The prevalence of asthma was 25.9% in skiers and 9.2% in the controls (p < 0.001). Median (IQR) age at first asthma‐related symptoms was higher in skiers than in the controls (13.0 (8.25–16.0) vs. 8.0 (2.25–11.75) years, p < 0.001), and the difference in asthma prevalence was evident only after the start of skiing career. Median (IQR) Asthma Control Test (ACT) score in skiers and controls with asthma was 22.0 (21–24) vs. 22.0 (19–24) (p = 0.611), and 89.0% of skiers and 77.4% of controls had well‐controlled asthma (ACT score ≥20). In skiers with asthma, 82.4% used regular inhaled corticosteroids (ICS), and 80.2% used bronchodilators. A fixed combination of ICS +long‐acting β2‐agonist was regularly used by 47.3% of the skiers and 22.6% of the controls with asthma (p = 0.016). In conclusion, asthma prevalence is about 2.5 times higher, and age at onset of asthma is later in skiers compared with the controls. Asthma in cross‐country skiers is mostly well controlled and on regular maintenance treatment.
Little is known about the true extent and severity of overuse injuries in sport, largely because of methodological challenges involved in recording them. This study assessed the prevalence of overuse ...injuries among Norwegian athletes from five sports using a newly developed method designed specifically for this purpose. The Oslo Sports Trauma Research Center Overuse Injury Questionnaire was distributed weekly by e‐mail to 45 cross‐country skiers, 98 cyclists, 50 floorball players, 55 handball players, and 65 volleyball players for 13 weeks. The prevalence of overuse problems at the shoulder, lower back, knee, and anterior thigh was monitored throughout the study and summary measures of an injury severity score derived from athletes' questionnaire responses were used to gauge the relative impact of overuse problems in each area. The area where overuse injuries had the greatest impact was the knee in volleyball where, on average, 36% of players had some form of complaint (95% CI 32–39%). Other prevalent areas included the shoulder in handball (22%, 95% CI 16–27%) the knee in cycling (23%, 95% CI 17–28%), and the knee and lower back in floorball (27%, 95% CI 24–31% and 29%, 95% CI 25–33%, respectively).
Purpose
To compare performance, physiological and biomechanical responses between double poling (DP) and diagonal stride (DIA) during treadmill roller skiing in elite male cross-country skiers.
...Method
Twelve skiers (
V
O
2peak
DIA
up
; 74.7 ± 3.7 ml kg
−1
min
−1
) performed two DP conditions at 1° (DP
flat
) and 8° (DP
up
) incline, and one DIA condition, 8° (DIA
up
). Submaximal gross efficiency (GE) and maximal 3.5 min time-trial (TT) performance, including measurements of
V
O
2peak
and maximal accumulated O
2
-deficit (MAOD), were determined. Temporal patterns and kinematics were assessed using 2D video, while pole kinetics were obtained from pole force.
Results
DIA
up
induced (mean, 95% confidence interval) 13% 4, 22 better 3.5-min TT performance, 7%, 5, 10) higher
V
O
2peak
and 3% points 1, 5 higher GE compared to DP
up
(all
P
< 0.05). DP
up
induced 120% higher MAOD compared to DP
flat
, while no significant differences were observed for
V
O
2peak
or GE between DP
flat
and DP
up
. There was a large correlation between performance and GE in DP and a large correlation between performance and
V
O
2peak
for DIA
up
(all
r
= 0.7–0.8,
P
< 0.05). No correlations were found between performance and VO
2peak
for any of the DP conditions, nor between performance and GE for DIA
up
(
r
= 0.0–0.2,
P
> 0.1).
Conclusion
At 8º uphill roller skiing, DIA
up
induce higher
V
O
2peak
, GE, and superior time-trial performance than DP
up
in elite male skiers. There was no difference between
V
O
2peak
or GE between DP
flat
and DP
up
. A large correlation was observed between DIA
up
performance and DIA
up
V
O
2peak
, while DP performance was best correlated to submaximal GE.
We investigated the effects of adding heavy strength training to a high volume of endurance training on performance and related physiological determinants in junior female cross‐country skiers. ...Sixteen well‐trained athletes (17 ± 1 years, 60 ± 6 kg, 169 ± 6 cm, VO2max running: 60 ± 5 mL/kg/min) were assigned either to an intervention group (INT; n = 9) or a control group (CON; n = 7). INT completed two weekly sessions of upper body heavy strength training in a linear periodized fashion for 10 weeks. Both groups continued their normal aerobic endurance and muscular endurance training. One repetition maximum in seated pull‐down increased significantly more in INT than in CON, with a group difference of 15 ± 8% (P < 0.01). Performance, expressed as average power output on a double poling ergometer over 20 s and as 3 min with maximal effort in both rested (sprint‐test) and fatigued states (finishing‐test), showed similar changes in both groups. Submaximal O2‐cost and VO2peak in double poling showed similar changes or were unchanged in both groups. In conclusion, 10 weeks of heavy strength training increased upper body strength but had trivial effects on performance in a double poling ergometer in junior female cross‐country skiers.
Greater gender differences have been found in exercise modes where the upper body is involved. Therefore, the present study investigated the influence of poling on gender differences in endurance ...performance by elite cross‐country skiers. Initially, the performance of eight male and eight female sprint skiers was compared during four different types of exercise involving different degrees of poling: double poling (DP), G3 skating, and diagonal stride (DIA) techniques during treadmill roller skiing, and treadmill running (RUN). Thereafter, DP was examined for physiological and kinematic parameters. The relative gender differences associated with the DP, G3, DIA and RUN performances were approximately 20%, 17%, 14%, and 12%, respectively. Thus, the type of exercise exerted an overall effect on the relative gender differences (P < 0.05). In connection with DP, the men achieved 63%, 16%, and 8% higher VO2peak than the women in absolute terms and with normalization for total and fat‐free body mass (all P < 0.05). The DP VO2peak in percentage of VO2max in RUN was higher in men (P < 0.05). The gender difference in DP peak cycle length was 23% (P < 0.05). In conclusion, the present investigation demonstrates that the gender difference in performance by elite sprint skiers is enhanced when the contribution from poling increases.
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).
This study aimed to: (i) analyze the load characteristics of 4 weeks cross-country skiing altitude training; (ii) analyze the relationships between methods of monitoring training load and ...physiological indicators changes of elite male Chinese cross-country skiers during this period. Practitioners collected load data during 4 weeks of altitude training camp. Participants performed maximal oxygen uptake, lactate threshold, body composition, and skierg power test before and after the training camp to investigate the changes in physiological performance. Edwards TRIMP, Lucia TRIMP, and session rating of perceived exertion were collected as internal load. Training distance, time recorded by the Catapult module were collected as external load. The result revealed a " pyramid " pattern in the load characteristics during the altitude training camp. The correlation between luTRIMP and percent change in physiological indicators was highest. Percentage changes in lactate threshold velocity (r = .78 95% CI -.01 to .98), percentage changes in lactate threshold HR (r = .71 95% CI .14- .99), percentage changes in maximum HR (r = .83 95% CI .19-1.00), percentage changes in skierg power-to-weight ratio (r = .75 95% CI -.28 to .98) had very large relationships with luTRIMP. In cross-country skiing altitude training, training loads should be reasonably controlled to ensure that athletes do not become overly fatigued. Methods of training load monitoring that combine with athletes' physiological characteristics and program characteristics have the highest dose-response relationships, it is an important aspect of cross-country ski training load monitoring. The luTRIMP could be a good monitoring tool in cross-country skiing altitude training.