| 1. |
- Bucher Sandbakk, Silvana, et al.
(author)
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Downhill turn techniques and associated physical characteristics in cross-country skiers
- 2014
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In: Scandinavian Journal of Medicine and Science in Sports. - : Blackwell Munksgaard. - 0905-7188 .- 1600-0838. ; 24:4, s. 708-716
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Journal article (peer-reviewed)abstract
- Three dominant techniques are used for downhill turning in cross-country skiing. In this study, kinematic, kinetic, and temporal characteristics of these techniques are described and related to skier strength and power. Twelve elite female cross-country skiers performed six consecutive turns of standardized geometry while being monitored by a Global Navigation Satellite System. Overall time was used as an indicator of performance. Skiing and turning parameters were determined from skier trajectories; the proportional use of each technique was determined from video analysis. Leg strength and power were determined by isometric squats and countermovement jumps on a force plate. Snow plowing, parallel skidding, and step turning were utilized for all turns. Faster skiers employed less snow plowing and more step turning, more rapid deceleration and earlier initiation of step turning at higher speed (r = 0.80–0.93; all P < 0.01). Better performance was significantly correlated to higher mean speed and shorter trajectory (r = 0.99/0.65; both P < 0.05) and to countermovement jump characteristics of peak force, time to peak force, and rate of force development (r = -0.71/0.78/-0.83; all P < 0.05). In conclusion, faster skiers used step turning to a greater extent and exhibited higher maximal leg power, which enabled them to combine high speeds with shorter trajectories during turns.
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| 2. |
- Ekenros, Linda, et al.
(author)
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Perceived impact of the menstrual cycle and hormonal contraceptives on physical exercise and performance in 1,086 athletes from 57 sports
- 2022
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In: Frontiers in Physiology. - : Frontiers Media S.A.. - 1664-042X. ; 13
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Journal article (peer-reviewed)abstract
- Female athletes train and compete under the potential influence of hormonal fluctuations during the menstrual cycle or during use of various hormonal contraceptives. Dysmenorrhea and premenstrual symptoms are common in the general population, as well as side effects of hormonal contraceptives. More detailed knowledge concerning prevalence and perceived impact of these symptoms on training and performance in different sports is required. The aim of the study was to 1) characterize perceptions of training and performance during the menstrual cycle phases and by hormonal contraceptive use in a large population of female athletes; 2) explore whether symptoms experienced are related to perceived performance; and 3) examine potential differences in these factors between athletes at different levels of performance. The study was based on self-reported data from 1,086 athletes from 57 sports at different performance levels via a web-based questionnaire. Thirty-seven percent (n = 407) of the athletes did not use hormonal contraceptives. In this group, menstrual cycle related symptoms were common across all athlete levels, particularly dysmenorrhea (74%, n = 300) and premenstrual symptoms (78%, n = 318), which also influenced perceived performance of aerobic fitness, muscle strength, mental sharpness, balance, and sleep quality. Sixty-three percent (n = 679) of the athletes used various hormonal contraceptives and 40% (n = 272) perceived a variety of side-effects. Physical performance was experienced equally independent of time-point of the pill-chart except for the period of inactive pills, which was associated with more negative impact. Nonetheless, only 18% (n = 191) of the athletes considered menstrual cycle or hormonal contraceptive issues when planning their training or competitions. These results indicate that greater focus is needed to identify and effectively treat different menstrual cycle and hormonal contraceptive related symptoms on an individual level.
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| 3. |
- Ekenros, Linda, et al.
(author)
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The perceived influence of menstrual cycle and hormonal contraceptives on training and performance: Comparison between football, handball, and orienteering
- 2023
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In: International journal of sports science & coaching. - : Sage Publications. - 1747-9541 .- 2048-397X.
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Journal article (peer-reviewed)abstract
- Recently, we published self-reported data concerning the perceived effects of the menstrual cycle and hormonal contraceptives on the training and performance of 1086 female athletes participating in 57 sports. However, studies comparing differences between sports with large sample sizes are lacking. The aim of this ancillary study was to compare the impact of the menstrual cycle and hormonal contraceptives on training and performance between the three largest sports in the cohort, that is, football, handball, and orienteering, as well as the knowledge and support provided to the female athletes engaged in these sports. The results are from a web-based questionnaire completed by 312 football players, 243 handball players, and 93 orienteers. A total of 54% of the orienteers planned their training based on the menstrual cycle, which was a higher proportion compared to football (45%) and handball (29%) players (p < 0.05). Fewer football players believed that the menstrual cycle had an impact on their performance during training and competition compared to the two other sports. A high proportion of the athletes used hormonal contraceptives in all three sports, but a lower proportion of the orienteers (40%) used hormonal contraceptives compared to football (76%) and handball players (66%) (p < 0.05). Football and handball players received overall more support than orienteers, and the support was mostly provided by a physiotherapist and/or a strength and conditioner coach besides the main coach. These findings demonstrate that the perceived influence of the menstrual cycle and hormonal contraceptives on training and performance differs between endurance athletes in orienteering compared to team-sport athletes in football and handball.
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| 4. |
- Sandbakk, Øyvind, et al.
(author)
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Energetic Cost and Kinematics of Pushing a Stroller on Flat and Uphill Terrain
- 2020
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In: Frontiers in Physiology. - : Frontiers Media SA. - 1664-042X. ; 11
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Journal article (peer-reviewed)abstract
- During early parenthood, walking and/or running while pushing a stroller is a common form of endurance exercise among both recreationally active individuals and athletes. Here, we investigate how pushing a stroller influences the energetic cost, gross efficiency (GE), and kinematic behavior of well-trained men and women while walking or running on flat and uphill incline. Eight men and nine women, all recreationally active, performed three 5-min submaximal tests of walking or running during four different testing sessions, in randomized order: with and without pushing a 24.3-kg stroller on a flat (1%; 6, 8/9, and 11/12 km/h for women/men) and uphill (10%; 5, 6.5/7.5, and 7.5/8.5 km/h for women/men) incline. Respiratory parameters, heart rate (HR), blood lactate concentration, and rating of perceived exertion (RPE) were determined and video-based kinematic analysis was performed in connection with all these tests. Except while walking on the flat incline, pushing a stroller increased the energetic cost of walking/running under all conditions (all p < 0.05). This was associated with shorter and more rapid strides on both inclines (all p < 0.05); however, GE was higher when pushing the stroller (p < 0.05). The increase in energetic cost of pushing the stroller was approximately threefold higher uphill than on the flat incline, and women were influenced more than men when running uphill at the highest speed (all p < 0.05). Here, we provide novel insights on the energetic cost and kinematic behavior of pushing a stroller while walking or running on flat and uphill inclines. The energetic cost of pushing a stroller was clearly higher than for unloaded exercise, coincided by shorter and more rapid strides, and especially pronounced on uphill terrain where also women were more influenced than men.
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| 5. |
- Sandbakk, Øyvind, et al.
(author)
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The Evolution of World-Class Endurance Training: The Scientist's View on Current and Future Trends
- 2023
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In: International Journal of Sports Physiology and Performance. - : Human Kinetics. - 1555-0265 .- 1555-0273. ; 18:8, s. 885-889
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Journal article (peer-reviewed)abstract
- Background: Elite sport is continuously evolving. World records keep falling and athletes from a longer list of countries are involved.Purpose: This commentary was designed to provide insights into present and future trends associated with world-class endurance training based on the perspectives, experience, and knowledge of an expert panel of 25 applied sport scientists.Results: The key drivers of development observed in the past 10-15 years were related to (1) more accessible scientific knowledge for coaches and athletes combined with (2) better integration of practical and scientific exchange across multidisciplinary perspectives within professionalized elite athlete support structures, as well as (3) utilization of new technological advances. Based on these perspectives, we discerned and exemplified the main trends in the practice of endurance sports into the following categories: better understanding of sport-specific demands; improved competition execution; larger, more specific, and more precise training loads; improved training quality; and a more professional and healthier lifestyle. The main areas expected to drive future improvements were associated with more extensive use of advanced technology for monitoring and prescribing training and recovery, more precise use of environmental and nutritional interventions, better understanding of athlete- equipment interactions, and greater emphasis on preventing injuries and illnesses.Conclusions: These expert insights can serve as a platform and inspiration to develop new hypotheses and ideas, encourage future collaboration between researchers and sport practitioners, and, perhaps most important, stimulate curiosity and further collaborative studies about the training, physiology, and performance of endurance athletes.
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| 6. |
- Severin, Anna Cecilia, et al.
(author)
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New insights from Norwegian and Swedish sports coaches' employment, practices, and beliefs during the first COVID-19 restriction period
- 2023
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In: Frontiers in Sports and Active Living. - : Frontiers Media SA. - 2624-9367. ; 5
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Journal article (peer-reviewed)abstract
- Introduction: This study (i) examined Norwegian and Swedish sports coaches’ employment, practices, and beliefs during the first wave of the COVID-19 pandemic, (ii) compared these aspects between coaches in Norway and Sweden, two countries with clearly different movement restrictions strategies in this period.Methods: An online survey was distributed to coaches via email and social media.The survey was open between June and August 2020. In total, 348 coaches responded, 141 from Norway, and 207 from Sweden.Results: Among responders, 2% had lost their job due to the pandemic, 17% had been furloughed, 28% worked from home office, and 39% worked as usual. Norwegian coaches were more likely to work from home (48% vs. 15%, p < .001), while Swedish coaches were more likely to work as usual (60% vs. 9%, p < .001). Coaches in both countries communicated less frequently with their athletes (p < .001) and had less in-person communication (p < .001) compared to pre-Covid levels. Larger declines existed among Norwegian coaches regarding communication frequency (p < .001) and in-person communication (p < .001). Video calls and phone calls usage increased (p < .001 and p = .009 respectively). We recorded low levels of concern among coaches about the effects of the pandemic on their relationship with their athletes. There were considerable levels of concern about athletes’ maintaining their motivation to train (Norway: 43.3%, Sweden: 50.7%), and low levels of concern about the coaches’ relationships with their athletes (Norway: 14.1%, Sweden: 17.8%).Discussion: Overall, this study showed the imposed movement restrictions had several negative consequences for the employment and work practices of sports coaches in Norway and Sweden. However, it also highlighted that coaches were able to adapt their work practices to the constraints and were able to maintain relationships with their athletes. The consequences raised in this paper can act as a guide during possible future lockdowns.
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| 7. |
- Solli, Guro S., et al.
(author)
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Changes in self-reported physical fitness, performance, and side effects across the phases of the menstrual cycle among competitive endurance athletes
- 2020
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In: International Journal of Sports Physiology and Performance. - 1555-0265 .- 1555-0273. ; 15:9, s. 1324-1333
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Journal article (peer-reviewed)abstract
- Purpose: To investigate changes in self-reported physical fitness, performance, and side effects across the menstrual cycle (MC) phases among competitive endurance athletes and to describe their knowledge and communication with coaches about the MC. Methods: The responses of 140 participants (older than 18 y) competing in biathlon or cross-country skiing at the (inter)national level were analyzed. Data were collected via an online questionnaire addressing participants' competitive level, training volume, MC history, physical fitness, and performance during the MC, MC-related side effects, and knowledge and communication with coaches about the MC and its effects on training and performance. Results: About 50% and 71% of participants reported improved and reduced fitness, respectively, during specific MC phases, while 42% and 49% reported improved and reduced performance, respectively. Most athletes reported their worst fitness (47%) and performance (30%) and the highest number of side effects during bleeding (P <.01; compared with all other phases). The phase following bleeding was considered the best phase for perceived fitness (24%, P <.01) and performance (18%, P <.01). Only 8% of participants reported having sufficient knowledge about the MC in relation to training, and 27% of participants communicated about it with their coach. Conclusions: A high proportion of athletes perceived distinct changes in fitness, performance, and side effects across the MC phases, with their worst perceived fitness and performance during the bleeding phase. Because most athletes indicate a lack of knowledge about the MC's effect on training and performance and few communicate with coaches on the topic, the authors recommend that more time be devoted to educating athletes and coaches.
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| 8. |
- von Rosen, Philip, et al.
(author)
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Offered Support and Knowledge about the Menstrual Cycle in the Athletic Community: A Cross-Sectional Study of 1086 Female Athletes
- 2022
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In: International Journal of Environmental Research and Public Health. - : MDPI. - 1661-7827 .- 1660-4601. ; 19:19
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Journal article (peer-reviewed)abstract
- Many female athletes perceive that symptoms related to the menstrual cycle such as dysmenorrhea, premenstrual symptoms, amenorrhea or side-effects of hormonal contraceptives negatively impact their training, performance, and general well-being. Knowledge and communication about female athletes’ health is therefore important in the sport community. The aims of this study were to explore the level of knowledge and communication about menstrual cycle issues and use of hormonal contraceptives in the athletic community and to describe the kinds of medical support offered to female athletes. A total of 1086 Swedish and Norwegian athletes from 57 different sports responded to a web-based questionnaire. Of these, 58% (n = 627) practiced team sports and 42% (n = 459) individual sports. Twenty-six percent (n = 278) of the athletes perceived their knowledge about female athlete health to be poor/very poor and the knowledge was most often acquired from medical staff. Fifty-three percent (n = 572) of the athletes perceived the knowledge acquired of their coaches as poor/very poor, even though a significantly (p < 0.001) higher proportion of athletes with a female coach (30%, n = 31) rated their coach’s knowledge as very good/good, compared to athletes with a male coach (5%, n = 31). Only 11% (n = 116) of the athletes discussed female health issues with their coach. The majority (81%, n = 842) of the athletes partly to strongly agreed that female athlete health is considered a taboo topic in the athletic community. Forty-seven percent (n = 510) of the athletes had access to a physiotherapist, while only three percent (n = 29) had access to a gynecologist. Low perceived knowledge, lack of communication and support demonstrate the need for a multi-professional medical team and enhanced educational efforts focused on female athlete health in the athletic community.
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| 9. |
- Andersson, Erik, 1984-, et al.
(author)
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Biomechanical analysis of the herringbone technique as employed by elite cross-country skiers
- 2014
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In: Scandinavian Journal of Medicine and Science in Sports. - : Wiley-Blackwell. - 0905-7188 .- 1600-0838. ; 24:3, s. 542-552
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Journal article (peer-reviewed)abstract
- This investigation was designed to analyse the kinematics and kinetics of cross-country skiing at different velocities with the herringbone technique on a steep incline. Eleven elite male cross-country skiers performed this technique at maximal, high, and moderate velocities on a snow-covered 15° incline. They positioned their skis laterally (25 to 30°) with a slight inside tilt and planted their poles laterally (8 to 12°) with most leg thrust force exerted on the inside forefoot. Although 77% of the total propulsive force was generated by the legs, the ratio between propulsive and total force was approximately fourfold higher for the poles. The cycle rate increased with velocity (1.20 to 1.60 Hz), whereas the cycle length increased from moderate up to high velocity, but then remained the same at maximal velocity (2.0 to 2.3 m). In conclusion, with the herringbone technique, the skis were angled laterally without gliding, with the forces distributed mainly on the inside forefoot to enable grip for propulsion. The skiers utilized high cycle rates with major propulsion by the legs, highlighting the importance of high peak and rapid generation of leg forces.
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| 10. |
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