Maximal Isometric or Eccentric Hamstring Strength-Which Test Modality Might Be More Suitable for Assessments in Youth Alpine Ski Racers?

Background: Physical fitness is an important component in the development of youth alpine ski racers. To write systematically planned and age-appropriate fitness programs athletes need to be physically tested at regular intervals at an early age. Although well-developed hamstring muscle strength is important for alpine ski racing performance and the prevention of serious knee injuries, it has not been well investigated, especially in youth athletes. Accordingly, the first aim of the present study was to assess the test-retest reliability of the maximum bilateral eccentric (MBEHS) and unilateral isometric (MUIHS) hamstring tests. The second aim of the present study was to assess whether the results of these two methods correlate and if it is possible to commit to one of the two methods to provide an economic test procedure. Methods: The first study included 26 (14 females/12 males) youth alpine ski racers aged between 12 and 13 years. All athletes performed two MBEHS and two MUIHS tests, 7 days apart. The intraclass correlation coefficient (ICC 3,1) and their 95% confidence intervals based on a consistency two-way mixed model were used to estimate the reliability of the two different test modalities. The second study included 61 (27 females/34 males) youth alpine ski racers aged between 10 and 13 years. All athletes performed one MBEHS and one MUIHS test. Bland-Altman plots and the 95% limits of agreement as well as correlations by Pearson (r) between the different test modalities were assessed. Results: In study 1 "poor" to "moderate" (MBEHS right leg 0.79 (0.58-0.90); left leg 0.83 (0.66-0.92); MUIHS right leg 0.78 (0.56-0.89); left leg 0.66 (0.37-0.83)) ICC values and 95% confident intervals were obtained. Standard error of measurement (SEM) between trails was between 18.3 and 25.1 N. Smallest detectable difference (SDD) was between 50.8 and 69.5 N. In study 2 mean differences between MBEHS and MUIHS was around 20 N with higher values for MBEHS. Significant moderate-to-strong correlations were found between the test modalities (r = 0.74-0.84, p <0.001). Conclusions: The MBEHS test has higher ICC values, lower CV values, higher SEM values and lower SDD values than the MUIHS test. All this suggests that the MBEHS test is more suitable than the MUIHS test to determine the maximum hamstring force in young alpine ski racers.

Nationality and sociocultural factors influence athlete development and sport outcomes: Perspectives from United States and Austrian youth alpine ski racing.

Geographical regions possess distinct sporting cultures that can influence athletic development from a young age. The United States (US) and Austria both produce elite alpine ski racers, yet have distinct sport structures (i.e., funding, skiing prominence). In this exploratory study, we investigated sport outcomes and psychological profiles in adolescent alpine ski racers attending skill development academies in the US (N= 169) and Austria (N= 209). Sport participation and psychological questionnaires (mental toughness, perfectionism, grit, coping, burnout) were administered to athletes. In Austria, athletes participated in fewer extracurricular sports, began competing and training younger, and accumulated less practice hours than athletes in the US. Athletes in the US reported greater burnout than athletes in Austria. Finally, in the US, women accumulated more practice hours and experienced more parental pressure than men, while men accumulated more practice hours in Austria. Austria's skiing-centric sport culture may encourage athletes to fully immerse into the sport, contributing to positive psychological outcomes. Reduced sport opportunities in the US beyond educational institutions may pressure athletes to practice more to ensure continued competitive skiing. Stressors for sport participation will be unique to gender in each country though, given their implicit gender stigmas for sport participation.

Training load characteristics and injury and illness risk identification in elite youth ski racing: A prospective study.

PURPOSE: The study aimed to investigate the role of training load characteristics and injury and illness risk in youth ski racing. METHODS: The training load characteristics as well as traumatic injuries, overuse injuries, and illnesses of 91 elite youth ski racers (age = 12.1 ± 1.3 years, mean ± SD) were prospectively recorded over a period of 1 season by using a sport-specific online database. Multiple linear regression analyses were performed to monitor the influence of training load on injuries and illnesses. Differences in mean training load characteristics between preseason, in-season, and post-season were calculated using multivariate analyses of variance. RESULTS: Differences were discovered in the number of weekly training sessions (p = 0.005) between pre-season (4.97 ± 1.57) and post-season (3.24 ± 0.71), in the mean training volume (p = 0.022) between in-season (865.8 ± 197.8 min) and post-season (497.0 ± 225.5 min) and in the mean weekly training intensity (Index) (p = 0.012) between in-season (11.7 ± 1.8) and post-season (8.9 ± 1.7). A total of 185 medical problems were reported (41 traumatic injuries, 12 overuse injuries, and 132 illnesses). The weekly training volume and training intensity was not a significant risk factor for injuries (p > 0.05). Training intensity was found to be a significant risk factor for illnesses in the same week (ß = 0.348; p = 0.044; R²â€¯= 0.121) and training volume represents a risk factor for illnesses in the following week (ß = 0.397; p = 0.027; R²â€¯= 0.157). CONCLUSION: A higher training intensity and volume were associated with increased illnesses, but not with a higher risk of injury. Monitoring training and ensuring appropriate progression of training load between weeks may decrease incidents of illness in-season.

Changes in Anthropometric and Fitness Characteristics Over a Decade of Young Elite Alpine Ski Racers.

PURPOSE: The aim of this study was to evaluate whether anthropometric and fitness characteristics have changed between former and current elite male and female Austrian young ski racers (U11-U15). METHODS: A battery of anthropometric, general, and skiing-specific fitness tests was conducted annually. In total, 1517 participants (846 males, 671 females) who were tested in 2005-2009 ("former athletes" n = 805) and 2015-2019 ("current athletes" n = 712) were included. Independent t tests and Cohen d were calculated to compare the two 5-y periods, separated by sex and age group. The level of significance was set at P < .05. RESULTS: No significant change in anthropometric characteristics was found over the decade. Current young ski racers performed significantly better in the maximal core flexion strength test in all age categories (ES = 0.88-1.50; P < .02). Core extension strength values were higher in current male U12 and female U12 and U13 athletes (ES = 0.54-0.71; P < .01) and better postural stability values in the lateral direction were found in the age categories U12 and U14 (ES = 0.36-0.68; P < .05), as well as in the forward/backward direction in the age categories U12-U14 (ES = 0.38-1.12; P < .03). Lower-leg extension strength values were apparent in the current U13-U15 age categories (ES = 0.36-1.03; P ≤ .001) and lower drop-jump reactive strength indices in the U13-U15 male athletes (ES = 0.49-0.80; P < .01). CONCLUSIONS: Current and former young ski racers differ significantly in some fitness parameters, which might lead to the assumption that some aspects (such as core strength) have gained more focus in athletic training during the last years compared with 15 y ago.

[Injuries and influencing factors on accidents in paragliding]. / Verletzungen und das Unfallgeschehen beeinflussende Faktoren im Paragleitsport.

Approximately 100 000 pilots worldwide practice the sport of paragliding. Most studies performed to date have been conducted retrospectively, using data from hospitals or emergency rescue organisations and focusing on injury patterns. Reasons for accidents and possible influencing factors have hardly been investigated. Therefore, the aim of this study was to analyse paragliding accidents in the Alps and to identify possible influencing factors. The data were taken from the "Flash-News" magazine (issues no. 149-160) covering the years 2015 to 2017. Only accidents occurring in Austria, Germany, Switzerland and Italy were considered. All in all, 487 accidents met the inclusion criteria of using a conventional paraglider and were analysed in this study. 88.5 % of the pilots involved were male and the average age was 42.9 ±â€Š13.7 years. Most accidents happened in summer and during the afternoon hours. The majority of incidents happened during the flight phase, but the comparison of tandem and solo pilots showed that tandem pilots had significantly more accidents during the take-off phase, whereas solo pilots had more accidents during the landing phase. Mistakes by pilots were identified as the main reason for accidents, followed by accidents caused by wind. In 71 of 487 (14,6 %) accidents, the pilots were not injured. If they were injured during the accident, the lower limbs were injured most frequently (35.5 %). In 45 of 487 accidents, the pilots died during the accident (9,2 %). The fact that more flights were executed during the summer months, combined with the more demanding flight conditions in summer (wind, weather, thermal conditions) may have led to the increased number of incidents in the period from April to August. Mistakes by pilots were identified as the major causes of accidents; therefore, training to handle difficult situations and the equipment are suggested. In general, the documentation of paragliding accidents is insufficient and inconsistent. The implementation of a harmonised, transnational form to document paragliding accidents is recommended to get unified and comparable data.

Acute Effects of a Short Bout of Physical Activity on Cognitive Function in Sport Students.

Physical activity is a promising intervention to restore cognitive function after prolonged sedentary periods. However, little is known about the effect of short physical activity bouts on cognition especially among individuals that are used to physical activity. Therefore, the goal of the present study was to assess the impact of a single ten-minute physical activity bout on the cognitive domain of visual attention compared to sedentary behavior in a population of physically active sport students. Using a randomized controlled design, 51 healthy and physically active sport students [mean age: 22.3 (SD: 2.0) years, 33.3% female] were allocated to one of the following interventions in the break of a two-hour study course: physical activity group (running for ten minutes) and sedentary control group. Visual attention was measured post-intervention using a modified trail making test. Pre-, post-, and 30 min after intervention, perceived attention, and affective states were measured. Between-group comparisons were used to analyze whether visual attention and/or changes in perceived attention or affective states differed between groups. The physical activity group showed significantly higher visual attention post-intervention compared with the sedentary control group, p = 0.003, d = 0.89. Perceived attention, p = 0.006, d = 0.87, and arousal, p < 0.001, d = 1.68, showed a significantly larger pre- and post-intervention increase in the physical activity group compared with the sedentary control group, which was not evident 30 min after intervention. A single ten-minute running intervention in study breaks might help to restore the basal visual attentional domain of cognition after prolonged sedentary periods more effectively compared with common sedentary behavior in breaks between study lessons.

Relationship of Changes in Physical Fitness and Anthropometric Characteristics over One Season, Biological Maturity Status and Injury Risk in Elite Youth Ski Racers: A Prospective Study.

Alpine ski racing is a sport with a high risk of injuries. In order to contribute to the longitudinal career development of young athletes, prevention measures should be elaborated. Therefore, the aim of the present study was to investigate prospectively the role of biological maturity status, and changes in anthropometric characteristics and physical fitness parameters over one season in elite youth ski racers younger than 15 years. Eighty-nine elite youth ski racers (39 females, 50 males), aged 10-14 years (mean age: 12.1 ± 1.3), were investigated. Anthropometric characteristics and physical fitness parameters were assessed prior and after the winter season; traumatic and overuse injuries were recorded over the 32 weeks. Binary logistic regression analyses (R² = 0.202-0.188) revealed that the biological maturity (Wald = 4.818; p = 0.028), and changes over the season in the jump agility test (Wald = 4.692; p = 0.03), in body height (Wald = 6.229; p = 0.013), and in leg length (Wald = 4.321; p = 0.038) represented significant injury risk factors. Athletes who could improve their jump agility performance more, had smaller changes in the anthropometric characteristics and who were closer to their peak height velocity were at a lower injury risk. In the context of injury prevention, regular neuromuscular training should be incorporated, and phases of rapid growth have to be considered.

Challenges of talent development in alpine ski racing: a narrative review.

Alpine ski racing is one of the most popular sports in many countries; nevertheless, selection disadvantages and severe injuries result in high dropout rates. In this review we summarize existing knowledge about the specific challenges associated with selection bias and injuries, and their effects on talent development in ski racing. The relative age effect (RAE) appears in all age categories of national Austrian and international alpine ski racing. Relatively younger athletes seem to only have a chance for selection if they are early maturing. Talent selection processes should consider both the biological maturity status as well as the relative age; additionally, a competition system based on a rotating cut-off date might contribute to a reduction of RAE. Youth and adolescent ski racers report lower injury rates compared to World Cup athletes. The knee was the most affected body part in relation to traumatic injuries. The most frequently reported overuse injuries were knee pain (youth) and low back pain (adolescent level). Athlete-related modifiable risk factors were core strength, neuromuscular control, leg extension strength and limb asymmetries. Based on these findings, prevention measures should be expanded to contribute to long-term injury prevention. In future research more multi-disciplinary, longitudinal studies should be performed.

Did the Relative Age Effect Change Over a Decade in Elite Youth Ski Racing?

The relative age effect (RAE) represents an asymmetry in birth quarter distribution, favoring athletes born early in the selection year and discriminating against late born athletes. The RAE was proven to be present in all age categories of national and international levels of alpine ski racing. Due to the existence of the RAE in all categories, it can be assumed that a selection error takes place favoring early born and early maturing youth ski racers. However, whether selection strategies have changed during the last years due to the high amount of research done in this field, has not been investigated so far in this sport. Therefore, the aim of the present study was to assess whether the magnitude of the RAE in youth ski racers aged 10-14 years has changed during the last decade by comparing the periods 2005-2009 ("former" athletes) and 2015-2019 ("current" athletes). Pupils of a well-known skiing-specific secondary modern school as well as members of the provincial ski team, who all competed at national levels, were included in the study. Next to the birth months, anthropometric characteristics (body height, weight, body mass index) were assessed. Chi-square tests were used to compare differences between the observed and expected relative age quarter distributions across five age categories (U11-U15). Additionally, Kruskal-Wallis-H-Tests were performed to assess differences in anthropometric characteristics between athletes of the four relative age quarters. Mann-Whitney U-Tests were performed to assess possible differences in anthropometric characteristics between former and current ski racers. A highly significant RAE was present in both former [χ2 (3, 764) = 60.36; p < 0.001; ω = 0.31] and current youth ski racers [χ2 (3, 702) = 43.13; p < 0.001; ω = 0.29] with an over-representation of athletes of Q1 (30.3-34.2%) and a clear under-representation of athletes of Q4 (14.8-15.0%). Generally, results indicated no change in the magnitude of the RAE in youth alpine ski racing over the past 10-15 years, emphasizing the robust nature of this phenomenon. No significant differences were found in any of the anthropometric characteristics between athletes of the four relative age quarters in both former and current athletes, indicating that relatively younger athletes of the last relative age quarter seem to have to have advanced anthropometric characteristics for being selected. Changes in the talent selection process should be performed to reduce the impact of the RAE.

Limb symmetry index in competitive alpine ski racers: Reference values and injury risk identification according to age-related performance levels.

PURPOSE: The aims of this study were to assess differences of limb symmetry index (LSI) in strength- and coordination-related tasks between high-level, competitive, noninjured ski racers of different age-related performance levels and to prospectively assess limb differences as a possible risk factor for traumatic and overuse injury in youth ski racers. METHODS: The study (Study 1) included 285 high-level competitive ski racers (125 females, 160 males) of 3 age-related performance levels and based on the school system: 95 youth (10-14 years, secondary modern school), 107 adolescent (15-19 years, grammar school), and 83 elite athletes (20-34 years). To investigate the second aim (Study 2), 67 of the 95 youth athletes were included and any traumatic or overuse injuries were prospectively recorded over 2 seasons. All athletes performed 4 unilateral tests (strength related: one-leg counter movement jump (OL-CMJ) and one-leg isometric/isokinetic press strength test (OL-ILS); coordination related: one-leg stability test (OL-ST) and one-leg speedy jump test (OL-SJ)). The LSI was calculated by dividing the dominant leg by the nondominant leg and multiplying by 100. Kruskal-Wallis H tests and binary logistic regression analyses were conducted. RESULTS: There were significant differences between the LSI of the 3 age-related performance-level groups only in the strength-related tests: the OL-CMJ (χ²(2, 285) = 9.09; p = 0.01) and the OL-ILS (χ²(2, 285) = 14.79; p < 0.01). The LSI for OL-ILS was found to be a significant risk factor for traumatic injury in youth ski racers (Wald = 7.08; p < 0.01). No significant risk factors were found for overuse injuries. CONCLUSION: Younger athletes display slightly greater LSI values only in the strength-related tests. The cut-off value of limb differences of <10% for return to sport decisions seems to be appropriate for elite athletes, but for youth and adolescent athletes it has to be critically discussed. It seems to be necessary to define thresholds based on specific performance tasks (strength vs. coordination related) rather than on generalizations, and age-related performance levels must be considered. Limb differences in unilateral leg extension strength represent a significant injury risk factor in youth ski racers.