ECSS Paris 2023: OP-AP04
INTRODUCTION: Alpine skiing performance needs strength, power, and balance, and high external forces and specific neuromuscular demands influence it. Traditional fitness assessments such as squat jump (SJ) and countermovement jump (CMJ) evaluate explosive power but may poorly address skiing’s strength requirements due to high-force outputs occurring at low angular velocities [1]. While anaerobic and aerobic capacities have been explored, their relationship with performance is ambiguous [2]. This study examines whether preseason strength test enhancements correlate with FIS point progression in slalom (SL) and giant slalom (GS), providing insight into strength tests predictive value for skiing. METHODS: Twenty-one alpine skiers were evaluated. Testing occurred at the preseason beginning (PRE) and conclusion (POST). The assessment battery comprised CMJ, SJ, and loaded squats at different body weight (BW) percentages. Peak force (PF), power, jump height, and velocity were quantified using a force platform [3]. Isometric strength was measured via belt isometric squat at 90°, 110°, and 130° knee angles, focusing on PF, early and late rate of force development (RFD), and maximum RFD. Pre-post differences were analyzed, and deltas between preseason tests were assessed. Competitive performance was quantified by the delta of FIS points between the seasons start and the best result achieved. Data were normalized via Z-score transformation. Statistical tools included Principal Component Analysis (PCA) to identify critical performance variables and multivariate regression to explore the relationships between predictor variables and competitive performance. RESULTS: The PCA revealed nine components accounting for over 90% of the total variance, with the initial three components explaining 54%. The first principal component was peak power and velocity in loaded squats and CMJ PF. The second one is related to body composition and PF in SJ and isometric squat at 90°. Finally, the third component encompassed power and velocity at the highest squat load alongside various RFD metrics. Multivariate regression revealed that peak power during squat at 150% BW is the primary predictor of performance improvements in SL and GS, with positive coefficients indicating strong explanatory power for the enhancements in both disciplines (R2 = 0.67 and 0.66, respectively). CONCLUSION: Results underscore the significance of lower-limb power output and high-load strength as pivotal factors in alpine skiing performance. Similar outcomes for SL and GS regression models suggest that enhancing maximum force production at slow movement velocities is more pertinent than augmenting fast, explosive movements. This indicates that conventional jump-based evaluations, which predominantly assess explosive power at elevated velocities, may inadequately capture the crucial strength attributes for skiing. 1 Javet et al. (2022); 2 Schoebersberger et al. (2020); 3 Penitente et al. (2023)
Read CV Giorgia Celeste CunibertiECSS Paris 2023: OP-AP04
INTRODUCTION: In youth sports, differences in biological maturation and relative age (RA) may lead to selection biases favouring early-born and early-maturing players due to advantages in psychological development and physique, respectively (1). However, no previous study has investigated the interaction of RA and biological maturity timing in ice hockey, considering elite junior and adult success. METHODS: Between 1998 and 2017, longitudinal anthropometrical data was collected in certified Swedish high school ice hockey programmes. For 2211 players, biological maturity timing was computed as z-scores of % adult height (z%AH) at term 1, compared to a Swedish reference (2). Birth dates for these players were used to calculate numerical relative age. Retrospective data on selection to the Swedish U16 national team (Team 16) and the National Hockey League (NHL) were retrieved from open databases. Next, absolute counts and proportions of players selected for Team 16 and the NHL were tabulated across quartiles of RA and z%AH. Generalized logistic regression models (GLM) including the predictors RA, z%AH, and their interaction, as well as other relevant confounders, were used to analyse selection probabilities. RESULTS: Distributions in RA and biological maturity timing differed significantly between Team 16 and the NHL. Considering Team 16, the group with the highest proportion of selected players was individuals born late in the year with early biological maturity timing (22%), although absolute counts in this group (n=13) were markedly less than in early-born players at any maturity timing, ranging from 21–28 selected players (10.8%–15.3%). In a GLM, RA and z%AH were independently identified as significant predictors of being selected for Team 16, and a significant interaction between RAE and z%AH was observed (P < 0.05). Considering adult success, players with late biological maturation timing (z%AH < -0.03) presented the highest proportion of players reaching the NHL, regardless of RA. Next, z%AH (P < 0.01), but not RA (P = 0.24), was significantly associated with NHL selection probabilities (favoring players who matured later than average), but there was no significant interaction between RA and z%AH (P = 0.44) in the employed GLM. CONCLUSION: Overall, there were independent and joint associations between RA and biological maturity timing considering the national Team 16 selection. Here, early maturity timing may cancel out disadvantages due to low RA. In contrast, late biological maturity timing was positively associated with NHL selection, but there was no interaction with RA. References 1 Sweeney, L. et al. Children 10, 130 (2023) 2 Albertsson-Wikland, K. et al. Acta Paediatr. 109, 754–763 (2020)
Read CV Erik NiklassonECSS Paris 2023: OP-AP04
INTRODUCTION: Concurrent training is necessary for short-track speed skating performance.To optimize the benefits of these sessions in a context where athletes might face a diminishing return phenomenon [1], ischemic preconditioning (IPC) may be a promising strategy [2,3]. METHODS: Tier 3 and 4 [4] short track speed skaters (n=21) participated in this randomized crossover study with 2 microcycles including 1 strength session (3 sets of 6 reps and 1 set to failure of trap bar squats at ~85% of 1 RM, with 90 seconds of rest between series) and 1 sprint interval (SIT) session 48 hours later (2 sets of 6 all-out sprints of 15 seconds on a bike, with 2 min of rest between sprints and 4 min between sets). During the strength sessions, mean velocity for each repetition was recorded with a Gym Aware device (Kinetic Performance Technology, Australia). During SIT sessions, power outputs were recorded using a Kickr trainer (Wahoo, Unites States of America). In a random order (AB or BA), athletes performed a microcycle during which strength and SIT sessions were preceded by IPC (week A; 3 x 5 min at 220 mmHg followed by 5 min at 0 mmHg, on each thigh) or a placebo condition (week B; 3 x 5 min at 20mmHg). For strength sessions, the outcome of interest was the number of repetitions completed during the 4th set while for SIT, a percent decrement score (PDecr) was calculated for each set. Furthermore, 24 or 48 hours after SIT, an on ice 4-laps time-trial (TT) was performed. Athletes had 2 or 3 days of receovery between microcycles. During both microcycles, the load of on-ice training was equivalent and the sequence of experimental sessions was the same. Paired-sample T-tests compared performance during IPC and Placebo weeks. Repeated measures ANOVA (Condition*Sex) verified if the effects of IPC varied depending on the sex. Effects sizes were calculated using Hedges’ g (rm). RESULTS: Due to injuries unrelated to the protocol and equipment malfunction, the final sample size was 19 for strength outcomes (9F) and 20 for SIT and TT (10F). IPC improved significantly the mean number of repetitions to failure during the last set (+2.84 reps; p = 0.015; g = 0.21). No significant differences were observed for mean velocity maintained during this set (p = 0.126; g = 0.07). During the SIT sessions, for both sets, no significant differences were observed for PDecr (Set 1: p = 0.556; g = 0.17; Set 2: p = 0.070; g = 0.52). Similar TT performance has been observed between experimental conditions (p = 0.294; g = -0.05). No interactions were found between sex and performance outcomes. CONCLUSION: IPC improves the total volume of repetitions performed to failure in short track speed skaters, which might indicate better resistance to fatigue. Furthermore, contrary to previous reports, adaptations were similar among males and females. 1.Thompson et al. (2024) 2. Rodrigues et al. (2023) 3. Cheng et al. (2021) 4. McKay et al. (2021)
Read CV Veronica Furno PugliaECSS Paris 2023: OP-AP04