Long-term sports participation and performance development are major issues in popular sports and talent development programs. This study aimed to provide longitudinal trends in youth female long jump performance development, participation, and relative age effects (RAEs), as longitudinal data for female athletes are missing. 51′894 season’s best results of female long jump athletes (n = 16′189) were acquired from the Swiss Athletics online database and analyzed within a range of 6–22 years of age. To examine longitudinal performance development and RAEs, data from athletes who participated in at least three seasons were selected (n = 41′253) and analyzed. Performance development was analyzed using age groups (AGs) and exact chronological age (CA) at competition. Differences between performances of birth quarters were analyzed using 83% confidence intervals (CIs) and smallest worthwhile change. Odds ratios (ORs) with 95% CI were used to quantify RAEs. With the traditional classification into age groups (AG), performances of athletes born between January and March (Q1) were significantly better than those born between October and December (Q4) from U8 to U17. Using exact CA resulted in similar performances in Q1 and Q4 until the U20 age category. The peak of participation was reached in the U12 category, and then decreased until the U23 category with a substantial drop at U17. Significant RAEs were observed from U8 to U19 and at U22. RAEs continuously decreased from U8 (large effect) to U14 (small effect). The present results show that differences in performance arise from the comparison of athletes in AGs. Thus, going beyond AGs and using exact CA, Q4 athletes could benefit from a realistic performance comparison, which promotes fair performance evaluation, un-biased talent development, realistic feedback, and long-term participation.
PURPOSE: To explore reasonable application purposes and potential confounders of the Swiss-Ski Power Test (SSPT) that is, since 2004, annually performed by all youth competitive alpine skiers of the under-16-years age category in Switzerland. METHODS: Preseason SSPT results (8 individual tests on anaerobic and aerobic capacity, muscle strength, and speed and coordination) of 144 skiers (57 female and 87 male) age 14.5 (0.7) years were analyzed along with anthropometry and biological age. Skiing performance was quantified as the actual performance points according to the Swiss national ranking. After the SSPT tests, skiers were prospectively monitored over 12 months using the Oslo Trauma Research Center questionnaire. Data were analyzed using multivariate analysis of variance, Pearson correlations, and multiple linear/binary logistic regression models. RESULTS: Biological maturation and SSPT results differed between sexes and age (P < .05). For males, SSPT results in the subdisciplines Swiss Cross, 1-leg 5-hop, and standing long jump were correlated to maturity offset, while for females only the obstacle run was related. High box jump and Swiss Cross scores were associated with skiing performance (P < .05). However, none of the SSPT subdisciplines was related to traumatic and overuse injuries (P < .05). CONCLUSIONS: The SSPT is a broadly implementable and cost-effective field test providing a general fitness profile of youth skiers. Around the growth spurt, differences in biological maturation should be considered. While SSPT results showed association with skiing performance, the test in its current form is limited for identifying injury-relevant physical deficiencies. Consequently, more specific tests may be required.
In football, annual age-group categorization leads to relative age effects (RAEs) in talent development. Given such trends, relative age may also associate with market values. This study analyzed the relationship between RAEs and market values of youth players.; Age category, birthdate, and market values of 11,738 youth male football players were obtained from the "transfermarkt.de" database, which delivers a good proxy for real market values. RAEs were calculated using odds ratios (OR) with 95% confidence intervals (95%CI).; Significant RAEs were found across all age-groups (; p; < 0.05). The largest RAEs occurred in U18 players (Q1 [relatively older] v Q4 [relatively younger] OR = 3.1) ORs decreased with age category, i.e., U19 (2.7), U20 (2.6), U21 (2.4), U22 (2.2), and U23 (1.8). At U19s, Q1 players were associated with significantly higher market values than Q4 players. However, by U21, U22, and U23 RAEs were inversed, with correspondingly higher market values for Q4 players apparent. While large typical RAEs for all playing positions was observed in younger age categories (U18-U20), inversed RAEs were only evident for defenders (small-medium) and for strikers (medium-large) in U21-U23 (not goalkeepers and midfielders).; Assuming an equal distribution of football talent exists across annual cohorts, results indicate the selection and market value of young professional players is dynamic. Findings suggest a potential biased selection, and undervaluing of Q4 players in younger age groups, as their representation and market value increased over time. By contrast, the changing representations and market values of Q1 players suggest initial overvaluing in performance and monetary terms. Therefore, this inefficient talent selection and the accompanying waste of money should be improved.
The aim of the present study was to investigate prospectively the role of biological maturity status, anthropometric percentiles, and core flexion to extension strength ratios in the context of traumatic and overuse injury risk identification in youth ski racing. In this study, 72 elite youth ski racers (45 males, 27 females) were prospectively observed from the age of 10 to 14 years. Anthropometric parameters, biological maturity status, and core flexion to extension strength ratios were assessed twice per year. Type and severity of traumatic and overuse injuries were prospectively recorded during the 4 years. Generalized estimating equations were used to model the binary outcome (0: no injury; 1: ≥1 injury). Factors tested on association with injury risk were sex, relative age quarter, age, maturity group, puberty status, core flexion to extension strength ratio, height percentile group, and weight percentile group. In total, 104 traumatic injuries and 39 overuse injuries were recorded. Age (odds ratio (OR) = 3.36) and weight percentile group (OR = 0.38) were significant risk factors for traumatic injuries (tendency: pubertal status). No significant risk factor for overuse injuries was identified (tendency: maturity group, puberty status, height percentile group). Future studies should focus on identifying risk factors for overuse injuries; growth rates might be of importance.
Competitive alpine skiers are subject to substantial risks of injury, especially concerning the anterior cruciate ligament (ACL). During “landing back weighted” episodes, hamstrings may partially counteract the anterior shear force acting on the tibia by eccentrically resisting the boot-induced drawer of the tibia relative to the femur. The aim of the present study was to provide novel descriptive data and sport-specific reference values on maximal eccentric hamstrings strength (MEHS) in competitive alpine skiers from youth to elite level, and to explore potential relationships with sex, age and biological maturation. 170 competitive alpine skiers were investigated: 139 youth athletes (51 females, 88 males; age: 13.8 ± 0.59 years) and 31 elite athletes (19 females, 12 males; age: 21.7 ± 2.8 years). MEHS was assessed by the (Vald Performance, Newstead, Australia). U15 female skiers presented lower MEHS compared to female elite skiers for both limbs (R = 210 ± 44 N vs. 340 ± 48 N, respectively, p < 0.001, and L = 207 ± 46 N vs. 303 ± 35 N, respectively, p < 0.001). Similarly, lower MEHS was observed in U15 male skiers compared to male elite skiers for both limbs (R = 259 ± 51 N vs. 486 ± 62 N, respectively, p < 0.001, and L = 258 ± 57 N vs. 427 ± 54 N, respectively, p < 0.001). Correlations between MEHS and chronological age were modestly significant only for the U15 group (r = 0.37 and p < 0.001). When the correlations for the U15 group were performed between MHES and maturity offset (obtained from the calculation of biological age, i.e., age at peak height velocity), statistical significance was reached by all the correlations run for 3 variables (Males < 0: r = 0.59, p < 0.0001; Males > 0: r = 0.70, p < 0.0001; and Females > 0: r = 0.46, p < 0.0001, start of maturity offset = 0). This cross-sectional description of MEHS in alpine skiers from youth to elite level highlights the importance of biological maturation for MEHS values in youth athletes and presents novel data that may offer insights into new approaches for injury prevention.
Relative age effects (RAE) generate consistent participation inequalities and selection biases in sports. The study aimed to investigate RAE across all sports of the national Swiss talent development programme (STDP). In this study, 18 859 youth athletes (female N = 5353; mean age: 14.8 ± 2.5 y and male N = 13 506; mean age: 14.4 ± 2.4 y) in 70 sports who participated in the 2014 competitive season were evaluated. The sample was subdivided by sex and the national level selection (NLS, N = 2464). Odds ratios (ORs) of relative age quarters (Q1-Q4) and 95% confidence intervals (CI) were calculated. In STDP, small RAE were evident for females (OR 1.35 (95%-CI 1.24, 1.47)) and males (OR 1.84 (95%-CI 1.74, 1.95)). RAE were similar in female NLS athletes (OR 1.30 (95%-CI 1.08, 1.57)) and larger in male NLS athletes (OR 2.40 (95%-CI 1.42, 1.97)) compared to athletes in the lower selection level. In STDP, RAE are evident for both sexes in several sports with popular sports showing higher RAE. RAE were larger in males than females. A higher selection level showed higher RAE only for males. In Switzerland, talent identification and development should be considered as a long-term process.
Introduction Relative age effects (RAEs) result in performance discrepancies between children and youth within one selection year (Cobley, Baker, Wattie, & McKenna, 2009). This generates consistent participation inequalities, selection biases and may lead to a drop out of potential talents. The aim of this study was to investigate RAEs across all sports of the national Swiss talent development program (STDP). Methods In this study, 18’859 (age range 5 to 20 y; female N = 5’353; mean age: 14.8±2.5 y and male N = 13’506; mean age: 14.4±2.4 y) youth athletes of 70 sports who participated in the 2014 competitive season were evaluated. All data were obtained from the national database of STDP. The sample was subdivided by sex, Olympic vs. non-Olympic sports and regional vs. national level selection (NLS, N=2464). The year was divided into four birth quarters (Q1: Jan. to Mar.; Q2: Apr. to Jun.; Q3: Jul. to Sept.; Q4: Oct. to Dec.). Odds ratios (ORs) and 95% confidence intervals (CI) were calculated for the comparison Q1 vs. Q4. Results In the whole STDP sample, youth athletes born in Q1 were 1.84 (95% CI 1.74, 1.95) for males, and 1.35 (95% CI 1.24, 1.47) for females times more likely to be selected than athletes born in Q4. Olympic sports showed higher ORs (males: 1.93 (95% CI 1.82, 2.05), females: 1.37 (95% CI 1.25, 1.5), than non-Olympic sports (males: 1.10 (95% CI 0.89, 1.31), females: 1.17 (95% CI 0.91, 1.5)). RAEs were higher in male NLS (OR 2.40 (95% CI 1.42, 1.97)) and were similar in female NLS (OR 1.30 (95% CI 1.08, 1.57)) compared to the lower selection level. NLS in Olympic sports showed higher ORs for males (2.54 (95% CI 2.11, 2.97)) and for females (1.34 (95% CI 1.09, 1.64)) than non-Olympic sports (males: 1.18 (95% CI 0.69, 1.82), females: 1.14 (95% CI 0.72, 1.8)). Discussion In the national Swiss talent development program, RAEs are evident for males and females in most sports. These results support existing literature demonstrating that popular Olympic sports show higher RAEs than non-Olympic sports and that RAEs are higher in males than females (Cobley et al., 2009). Higher selection level showed higher RAEs only for males. RAEs reflect a type of developmental barrier that may be preventable by implementing appropriate solutions in the future (Romann & Cobley, 2015). Especially for a small nation like Switzerland, with correspondingly few sport talents, any future reduction of RAEs may provide a substantial performance enhancement at elite senior level.
Einführung Gute physische Voraussetzungen sind für Spitzen Athleten im Ski Alpin entscheidend. Die physische Leistung der Nachwuchsathleten wird mit dem Swiss-Ski Power Test (SSPT) getestet. Der SSPT besteht aus Schweizerkreuz, Liegestütz, 5er Hupf, Standweitsprung, TDS-Hindernislauf, Twist, 12-Minuten-Lauf und High-Box Jump. Statistische Analysen zum SSPTs wurden bereits durchgeführt (Gorski, Rosser, Hoppeler, & Vogt, 2014; Marconi, 2013). Erkenntnisse zur Leistungsentwicklung im SSPT von späteren Elite-Athleten fehlen derzeit. Methode Die Daten von 2168 Athleten in den Altersklassen von 12 bis 18 Jahren im Zeitraum von 2004 bis 2016 wurden retrospektiv analysiert. Erfolgreiche Athleten (EG; n=85) wurden mit Nicht erfolgreiche Athleten (NG; n=2083) verglichen. EG gehören bzw. gehörten einem Swiss-Ski Kader (C bis NM) an. NG sind Nachwuchsathleten, die nie einen Swiss-Ski Status erreicht haben. Alle statistischen Vergleiche wurden mittels T-Test (Normalverteilung) bzw. Mann-Whitney U-Test in Jahreskategorien durchgeführt. Resultate Signifikante Unterschiede ergaben sich für Schweizerkreuz, 5er Hupf, Standweitsprung, TDS-Hindernislauf und High-Box Jumpab 15 Jahren bis 18 Jahren. Von 12 bis 14 Jahren zeigten sich nur vereinzelt signifikante Unterschiede. Die grössten Unterschiede ergaben sich über alle Altersgruppen im High-Box Jump. Der 12-Minuten-Lauf zeigte die wenigsten Unterschiede zwischen Gruppen. Diskussion Die Ergebnisse zeigen, dass einzelne Tests am Ende der Pubertät eine gute Prognose für späteren Erfolg darstellen. Mit diesen Daten können Referenzwerte für Schweizer Nachwuchsathleten im Ski Alpin berechnet werden. Sie geben zusätzlich Hinweise für die Gewichtung der einzelnen Tests des SSPT in der Selektion der Nachwuchs Ski Athleten.
Consideration of maturity is recommended in the talent identification and development process. Skeletal age (SA), prediction of age of peak height velocity (APHV) and an estimation of biological maturation by coaches’ eye of 121 soccer players were compared. The SA of soccer players was 13.9 ± 1.1 years, and did not differ significantly from chronological age (CA). Agreement between the SA-CA classifications and APHV was 65.5%. Spearman rank-order correlation (rs) between maturity classifications was moderate, kappa (k) was 0.25. Agreement between SA-CA classifications and coaches’ eye was 73.9%. The rs between maturity classifications was strong, k was 0.48, which was better than the widely used APHV assessment. Therefore, estimations of experienced coaches seem to be an acceptable alternative method for classifying maturity in youth athletes.
