2020 abstracts poster sessions
E. P. Andersson 1,2 & N. Lögdal 1
1 Swedish Winter Sports Research Centre, Department of Health Sciences, Mid Sweden University, Östersund, Sweden.
2 School of Sport Sciences, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
Purpose: This study aimed to compare the physiological responses and pacing strategies between double poling (DP) and diagonal-stride (DS) treadmill roller-skiing.
Methods: Fifteen male cross-country skiers (age, 27±5y) performed a submaximal protocol consisting of 8×4-minute stages followed by a self-paced 4-minute time trial (TT), one test using each sub-technique (DP [1.5°] and DS [6.5°]).
Results: The average gross efficiency during the submaximal stages was 17.5 ± 1.3% and 20.0 ± 0.7% for DP and DS, respectively (main effects for sub-techniques, stages, and interaction [all P<0.01]). The average power outputs during the TT were 278 ± 29 and 409 ± 38 W. Average anaerobic metabolic rate was 273 ± 162 and 380 ± 66 W (P=0.014) in DP and DS respectively, corresponding to relative anaerobic energy contributions of 14 ± 7% and 18 ± 3% (P=0.024). The peak VO2 was 67 ± 4 mL/kg/min for DP and 70 ± 3 mL/kg/min for DS (P=0.001). The average required metabolic power over the four quarters of the TT (i.e., 1-minute averages) were for DP, 1.85, 1.91, 1.82, and 1.84 kW; and for DS, 2.09, 2.10, 2.00, and 2.04 kW (main effects for sub-techniques [P<0.001] with no time or interaction effects).
Conclusions: The main findings of the current study were that gross efficiency, TT power output, TT anaerobic metabolic power, and TT peak VO2 all were considerably lower for DP than DS while the pacing strategies were similar.
Practical applications: These findings are of relevance when optimizing training regimes and pacing strategies.
B. Bruhin 1*, & R.J.F. Janssen 1 , S. Guillaume 2, M. Gander 1, F. Oberle 3, S. Lorenzetti 1 & M. Romann 1
1 Swiss Federal Institute of Sport Magglingen (SFISM), Magglingen, Switzerland
2 Haute Ecole d’Ingénerie et de Gestion du Canton de Vaud, Yverdon-les-Bains, Switzerland
3 Sports Medical Research Group, Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
Purpose: This pilot study aims to address differences in course setting and steepness of different course sections (flat – medium – steep) in giant slalom and compare them to performance parameters among young (U12, U14, U16) and older (U18, U21, elite) male alpine skiing athletes.
Methods: A total sample size of 57 male athletes was examined; 7 from elite level, 11 from U21, 13 from U18, 6 from U16, 13 from U14 and 7 from U12. The athletes wore a portable global navigation satellite system (GNSS) sensor to extract performance parameters. The runs were divided into flat, medium and steep sections. Mean values per section of performance parameters (speed, time per turn, etc.) and course setting variables were calculated and used for further analysis.
Results: In total, 192 run sections from 88 runs were recorded and analysed. Comparisons in course settings between young and older categories showed no significant differences. However, turning angles and horizontal gate distances were smaller in flat sections. Average speed (49.77 km/h vs. 65.33 km/h) and time per turn (1.74 s vs. 1.41 s) differed significantly between young and U21/elite categories. In medium terrain sections, U21 and elite athletes spent more time in the gliding phase compared to the other categories.
Conclusions: Given similar course setting and steepness, speed and time spent in the gliding phase may increase concurrently with the technical and tactical skills of the athlete.
Practical Applications: The present findings could be crucial for understanding technique and performance development from youth to elite level.
M. Danemar 1, C.J. Sundberg 1, K. McGawley 2, Ø. Karlsson 2
1 Karolinska Institutet, Stockholm
2 Mid Sweden University, Östersund
Purpose: The aim of this study was to examine the relationships between health problems, defined as injury or illness, on performance during a competitive season among elite XC skiers (9 females; 9 males).
Methods: Data was collected for 17 weeks using the Oslo Sports Trauma Research Center questionnaire on health problems, resulting in a total of 296 athlete weeks’ worth of data. Prevalence and severity measures were calculated for all health problems and substantial health problems (defined as problems leading to moderate or severe reductions in training volume or sports performance, or complete inability to participate). Acssociations between health problems and performance were analyzed using regressions with change in FIS points from the 2018/19 season to the 2019/20 season, representing performance.
Results: The average weekly prevalence of all health problems was 19% (95% CI: 3.5% to 34%). Prevalence of substantial health problems was 12% (95% CI: -0.4% to 25%). Illness was the most common health problem, representing 74 days (71%) of total time loss compared to overuse injuries (12 days, 12%) and acute injuries (18 days, 17%). There was no significant association between the cumulative severity score of health problems (-0.03; 95% CI: -0.08 to 0.02; p = 0.25).
Conclusions: No relationship was identified between the cumulative severity of health problems and performance.
Practical applications: The findings from this study suggest that ongoing surveillance programs could be useful in mapping athlete injury and illness trends.
M. Gander 1, M. Javet 1 & B. Bruhin 1
1 Swiss Federal Institute of Sport Magglingen (SFISM), Magglingen, Switzerland
Purpose: This pilot study aims to examine whether the Recovery-Stress Questionnaire for Athletes (RESTQ-Sport) is a possible verification tool to make a valid prognosis of training load in alpine ski racers.
Methods: Eleven female athletes of the Swiss Ski Alpine Team C (18.3 ± 1.1 years) completed the RESTQ-Sport on a weekly basis during the training year 2019/2020. In total 473 questionnaires were completed. All data were z-transformed and analysed individually.
Results: The RESTQ-Sport correlated significantly with race results in one athlete (R2 = .366), training intensity in three athletes (R2 = .176; R2 = .252; R2 = .241), sleep quality in three athletes (R2 = .350; R2 = .130; R2 = .168) as well as pain intensity in one athlete (R2 = .364) suffering from an overuse injury. Moreover, two athletes showed significantly lower mean scores during the general preparation than during the specific preparation and competition period, respectively.
Conclusions: In some athletes improved recovery-stress states were associated with better race results and sleep quality as well as decreased training intensity and pain intensity in overuse injuries. Further research should investigate the cause-and-effect-relationship. Major differences in the recovery-stress states during the training year highlighted the importance of an individual evaluation of the RESTQ-Sport.
Practical Applications: The questionnaire may provide valuable input to coaches regarding the athlete's recovery-stress state in monitoring training load when applied in a multidisciplinary network.
K.E.T. Giljarhus 1, O. Elfmark 2, R. Reid 3, F.F. Liland 4, L. Oggiano 4
1 University of Stavanger, Stavanger, Norway
2 Norwegian University of Science and Technology, Trondheim, Norway
3 Norwegian Ski Federation, Oslo, Norway
4 Nabla Flow AS, Stavanger, Norway
Purpose: Downhill skiing is a sport with small margins where often only a few hundredths of a second separates the top contenders. Aerodynamic drag accounts for 80-90 % of the total braking force of a downhill skier. The purpose of the present work is to gain insight into the flow around a downhill skier to reduce the aerodynamic drag.
Methods: In this work, we apply detailed computational fluid dynamics to investigate potential improvements in the position of a downhill skier in the fully tucked position. The geometry for the simulation was obtained by 3D scanning of an athlete from the Norwegian alpine national team.
Results: A simulation of the scanned position showed a problem with flow separation from the hip area. Digital adjustments were made to the position leading to an overall reduction in drag of approximately 20 %.
Conclusions: It is important to understand the underlying flow physics to improve aerodynamics in downhill skiing, and computational fluid dynamics is a useful tool for this purpose. This work has the potential to further improve aerodynamics in downhill skiing through testing and optimization of more positions.
Practical applications: Being able to use flow simulations could improve aerodynamical research in alpine skiing, as wind tunnel testing is time consuming for the athlete and expensive. This study shows how individual adjustments and testing of aerodynamical drag can be performed with minimal interaction by the athlete. This can also enhance the understanding of suit development in alpine skiing.
Irina Hamberg 1,2, Erik Andersson 1, Paulo C do Nascimento Salvador 3, Kerry McGawley 1
1 Swedish Winter Sports Research Centre, Department of Health Sciences, Mid Sweden University, Östersund, Sweden
2 Idrottsprogrammet, Wargentinskolan, Jämtlands Gymnasium, Östersund, Sweden
3 Physical Effort Laboratory, Sports Center, Federal University of Santa Catarina, Florianopolis, Brazil
Purpose: This study aimed to compare physiological factors and cycle characteristics during cross-country (XC) roller-skiing at matched inclines and speeds using the double-poling (DP) and diagonal-stride (DS) sub-techniques in male and female XC skiers.
Methods: Following familiarization to treadmill roller-skiing, 23 well-trained junior XC skiers (12 males, 11 females; age 18.2 ± 1.2 y) completed two roller-ski tests in a randomized order using either DP or DS. The exercise protocols were identical and included a 5-min warm-up, 4 x 5-min submaximal stages and an incremental test to exhaustion all performed at a 5° incline.
Results: Submaximal energy cost, mean O2 kinetics response time, blood lactate concentration, heart rate (HR), rating of perceived exertion and cycle rate were all significantly lower during DS compared to DP, while cycle length was significantly higher (all P<0.001). In addition, O2peak and peak HR were higher and time to exhaustion was longer during DS compared to DP (all P<0.001).
Conclusion: In well-trained junior XC skiers, DP was found to exert a greater physiological load than DS during uphill XC roller-skiing at submaximal intensities. Moreover, athletes were able to ski for longer and reached markedly higher O2peak and HR values during incremental exercise to exhaustion when using DS compared to DP.
Practical application: It is important to consider the specific demands of DS and DP when planning and implementing training programs and sessions, as these two sub-techniques elicit distinct responses among junior XC skiers.
Oona Kettunen 1, Maria Heikkilä 2, Vesa Linnamo 1, Johanna Ihalainen 1
1 Faculty of Sport and Health Sciences, University of Jyväskylä, Vuokatti, Finland
2 Department of Food and Nutrition, Faculty of Agriculture and Forestry, University of Helsinki, Finland
Purpose: To provide novel information on how nutrition knowledge affects energy availability and carbohydrate intake in young female cross-country skiers.
Methods: 19 female skiers (age 16.7±0.7 years) from the Finnish youth national team filled in 48-hour weighted food and training logs from 2 to 12 days before, and during a 5-day training camp. Energy availability (EA) was assessed in relation to fat free body mass (bioimpendance) and carbohydrate intake in relation to whole body mass. Dietary intake was compared to current recommendations for endurance athletes. Nutrition knowledge score about “nutrition recommendations for endurance athletes” was assessed via validated questionnaire.
Results: 11% of athletes had optimal EA at home (mean 33.7 ± 9.6 kcal/kg/d) and 42% at camp (mean 40.3 ± 17.3 kcal/kg/d). Nutrition knowledge correlated with EA at home (r=0.52, p=0.023). 74% of athletes failed to meet recommendations for carbohydrate intake at home (mean 5.0±1.2 g/kg/d) and 63% of them at camp (mean 7.1±1.6 g/kg/d). Nutrition knowledge correlated with carbohydrate intake at home (r=0.62, p=0.005) and at camp (r=0.52, p=0.023). There was no association between exercise energy expenditure and nutrition knowledge.
Conclusions: Young female cross-county skiers had difficulties to meet recommendations for optimal EA and carbohydrate intake. Better nutrition knowledge and eating from buffet at prescheduled times (as at camp) may help young athletes to meet these recommendations.
Practical applications: As suboptimal EA and carbohydrate intake may compromise athletes´ performance and health, these findings highlight the importance of enhanced high-quality nutrition education on young endurance athletes.
M Köykkä 1, S Ihalainen 2, V Linnamo 1, K Ruotsalainen 1, K Häkkinen 1, MS Laaksonen 3
1 Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
2 KIHU – Research Institute for Olympic Sports, Jyväskylä, Finland
3 Swedish Winter Sports Research Centre, Department of Health Sciences, Mid Sweden University, Östersund, Sweden
Purpose: This study focused on investigating differences in shooting performance and performance related factors between two different aiming strategies (HOLD, low approach velocity 0.4-0.2 seconds before triggering, and TIMING, high approach velocity) in biathlon standing shooting.
Methods: 23 biathletes fired 8x5 standing shots at rest (REST) and 2x5 shots during a race simulation (RACE). Shooting performance (hit point distance from the center of the target) and aiming point trajectory were measured from each shot.
Results: Both groups demonstrated similar shooting performance both at REST and in RACE. In HOLD, better shooting performance was related to smaller distance of the aiming point mean location (REST r=0.93, p<0.001, RACE r=0.72, p=0.018) and higher time spent within ⅔ of the distance of the hit area edge from the center 0.6-0.0 seconds before triggering (REST r=-0.88, p=0.001, RACE r=-0.73, p=0.016). In TIMING, better shooting performance was related to lower aiming point total velocity 0.6-0.0 seconds before triggering (REST r=0.77, p=0.009, RACE r=0.88, p=0.001) and less aiming point movement 0.2-0.0 seconds before triggering (REST r=0.82, p=0.003, RACE r=0.72, p=0.012).
Conclusions: Biathletes using the hold strategy should focus on improving their aiming accuracy and holding ability. Biathletes using the timing strategy should focus on their ability to approach the target straightforwardly at a controlled velocity and the ability to minimize the movement of the aiming point during the triggering phase.
Practical applications: Biathletes and coaches should be aware of the strategy in use and plan the shooting technical exercises accordingly.
I Löfquist 1 & Glenn Björklund 1
1 Swedish Winter Sports Research Centre, Department of Health Sciences, Mid Sweden University, Östersund, SWEDEN.
Purpose: The purpose of this study was to investigate the magnitude of force a slopestyle skier is exposed to when landing either forward or switch in a big air jump.
Methods: Ten male freeskiers (age 23 ± 6 years; height 179.2 ± 5.4 cm; body mass 72.5 ± 8.6 kg; mass of equipment 16.7 ± 1.4 kg; total mass 89.2 ± 8.6 kg) participated and each performed five 180 jumps and five switch 180 jumps in a randomized order. Forces were quantified using pressure insoles.
Results: The results showed a force of 1446 ± 367 N (2.04 ± 0.46 times body mass) for the 180 jump and a force of 1409 ± 257 N (1.99 ± 0.28 times body mass) for the switch 180 jump. There was no difference in force between the 180 jump and the switch 180 jump, p=0.582. There was a trend for the switch 180 for a correlation between a heavier body mass and a greater force (r = 0.604, r2 = 0.365, p = 0.064) as well as a heavier total mass and a greater force (r = 0.621, r2 = 0.385, p = 0.055).
Conclusions: This study shows that the force when landing a big air jump is roughly twice the slopestyle skier’s body mass, but no difference in force was seen between performing a 180 or a switch 180 jump. The force of twice the body mass could therefore be considered a minimum value for slopestyle skiing. If an athlete performs a more difficult trick, the requirements for the strength training may want to be higher.
Practical Applications: These findings can help to create training programs for the dry land training that will facilitate the handling of similar forces during the on-snow season.
R Mäki-Heikkilä 1, J Karjalainen 1,2, J Parkkari 3,5, M Valtonen 4, L Lehtimäki 1,2
1 Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
2 Allergy Centre, Tampere University Hospital, Tampere, Finland
3 Tampere Research Center of Sports Medicine, UKK Institute, Tampere, Finland
4 KIHU – Research Institute for Olympic Sports, Jyväskylä, Finland
5 Tampere University Hospital, Tampere
Purpose: Respiratory tract infections (RTI) are one of the main causes preventing athletes from training and competing and increase risk for major complications and longer breaks from training. The aim of this study was to investigate the burden of illnesses during one season in cross-country skiers.
Methods: In spring 2019, we invited via the Finnish Ski Association by mail all athletes (n = 1282) that had enrolled in their highest level national competition from 13 years of age to seniors.
Results: The response rate was 27% (n = 351) and 58% of the responders were women. The mean age was 18.8 (SD 6.1) years. In total, 86% of the skiers refrained from training due to RTI and 66% missed a competition due to illness at least once during the season. On average, skiers had 15.8 days absence of training due to illness. Although severe symptoms prevent skiers from competing and training, 48 % reported training and 23 % reported competing while having common cold. There were no notable differences between sexes or between juniors and seniors (cut-off age 16 years) in training or competing during RTI. Skiers with asthma refrained more from competing and had more days of illness compared to skiers without asthma (77% vs. 62%, p = 0.011, 19.0 vs. 14.7 days, p = 0.014).
Conclusions: RTIs cause a major burden on cross-country skiers often preventing training and competing, and asthma increases absence from training and competing.
Practical Applications: Proper guidance for the risk of complications in athletes should be considered.
K. McGawley 1, C. Van Waerbeke 1,2, K.-J. Westberg 1, E. Andersson 1
1 Swedish Winter Sports Research Centre, Mid Sweden University, Östersund, Sweden
2 Faculty of Sport Sciences, Aix-Marseille University, Marseille, France
Purpose: The aim was to compare the physiological and performance effects of longer versus shorter recovery periods between the three knock-out races of a simulated sprint XC ski competition.
Methods: Eleven well-trained XC skiers completed two simulated sprint competitions on a treadmill, each involving four roller-ski bouts (prologue, P; quarter-final, QF; semi-final, SF; final, F) at a 4° incline using gear 3 skating. The first three bouts (FIXP, FIXQF and FIXSF) were completed at 95.6% of each individual’s pre-determined maximal sprint speed. The final bout (STTF) was a maximal, self-paced time-trial. The recovery durations between the QF, SF and F simulated real-world conditions for maximum (MAX-REC) or minimum (MIN-REC) recovery.
Results: FIXP, FIXQF and FIXSF were completed in a fixed time and power output of 191.6 ± 16.7 s and 4.29 ± 0.35 W·kg-1, respectively. The STTF was completed significantly faster during MAX-REC compared to MIN-REC (179.2 ± 18.1 s versus 184.6 ± 20.0 s; P=0.009) and power output was greater during MAX-REC compared to MIN-REC (4.61 ± 0.44 W·kg-1 versus 4.48 ± 0.47 W·kg-1; P=0.010). There were no significant differences in physiological responses during the two STTF conditions (P>0.005), but pacing profiles showed a tendency for power output to be maintained more effectively over the first three quartiles during MAX-REC compared to MIN-REC.
Conclusions: Maximizing recovery between the knockout races of a sprint XC ski competition is beneficial to performance.
Practical applications: These findings have implications for the tactical choices made by skiers when selecting their sprint heats.
O, Sollie 1, Ø, Gløersen 1, M, Gilgien 1,2, T, Losnegard 1
1 Department of Physical Performance, Norwegian School of Sports Sciences, Oslo, Norway
2 St. Moritz Health and Innovation Foundation, Samedan, Switzerland
Purpose: To describe differences in pacing patterns in young compared to adult competitive cross-country skiers.
Methods: Eleven young male skiers (YOS) (14.4±0.5 years, V̇O2peak 63.9±2.8 mL∙kg-1∙min-1) and eight adult male skiers (ADS) (22.6±4.3 years, V̇O2peak 77.4±4.4 mL∙kg-1∙min-1) performed a free technique rollerski time trial (TT) over a distance of 4.3 km (YOS) and 13.1 km (ADS) to simulate normal racing distances. A GNSS system was used to track position, and speed. Skiing-economy and V̇O2peak were measured on an additional day to calculate the relative oxygen demand (V̇O2dem) in 13 segments of the TT.
Results: YOS were slower than ADS in all types of terrain (mean speed difference of 13%), with differences for uphills of 19%, undulating terrain of 11% and downhills of 8% (all P<.05). The mean relative V̇O2dem tended to be higher for YOS compared to ADS (120 vs. 112% of V̇O2peak, P=.09) and the difference was more pronounced in the initial four segments of the race (130 vs. 110% of V̇O2peak, P<.01). Time loss (s∙m-1) for YOS compared to ADS drastically increased when inclination increased.
Conclusion: Over an age-normalized distance, young skiers follows the same variable pacing, but tend to exhibit higher mean exercise intensity than adult elite skiers, with a more pronounced positive pacing pattern.
Practical applications: The higher effort for the young skiers during the initial phases of TT may imply that younger skiers could benefit from adopting more conservative pacing to enhance their performance. Younger skiers might benefit from focusing on efficient transitions into the uphills to prevent time loss.