The Impact of a Swimming Training Season on Anthropometrics, Maturation, and Kinematics in 12-Year-Old and Under Age-Group Swimmers: A Network Analysis

Open Water Swimming in Elite Triathletes: Physiological and Biomechanical Determinants

This study aimed (i) to analyze the 1500 m open water swimming performance, (ii) to examine the associations between physiological and biomechanical variables with swimming performance, and (iii) to determine which variables can predict swimming performance in triathletes. Fourteen elite triathletes (23.4±3.8 y) performed a 1500 m test in open water swimming conditions. Swimming performance was assessed using World Aquatics Points Scoring, and data were obtained from the 1500 m open water swimming test. Heart rate, end-exercise oxygen uptake (EE˙VO2) and blood lactate concentrations were measured. The initial 250 m of the 1500 m swimming test presented the highest values of biomechanical variables in males (i. e. swimming speed, stroke rate (SR), length (SL), index (SI)). A decrease in SL was observed in the last 250 m in both sexes. Positive association were found between EE˙VO2 (r=0.513; p=0.030), swimming speed (r=0.873; p<0.001) and SI (r=0.704; p=0.002) with swimming performance. In contrast, time constant of the oxygen uptake (r=-0.500; p=0.034) and buoy-turn times (r=-0.525; p=0.027) were negatively associated with performance. SI was the main predictor (R 2=0.495) of open water swimming performance in triathletes. In conclusion, triathletes and coaches must conduct open water training sessions to maximize SI (i. e. swimming efficiency).

Changes in Young Swimmers' In-Water Force, Performance, Kinematics, and Anthropometrics over a Full Competitive Season

The aim of the present study was to analyze changes in young swimmers' in-water force, performance, kinematics, and anthropometrics during one full competitive season. Twenty-five swimmers (11 girls and 14 boys, 12.04 ± 0.16 years) were assessed over four distinct time points throughout a competitive season. The in-water force of both hands (D, dominant; ND, non-dominant) was retrieved during two bouts of 25 m front crawl allowing the estimation of the symmetry index. The velocity (v25) was calculated from the time to complete the 25 m and considered the performance outcome, while the stroke rate, stroke length, and the stroke index were used as kinematic variables. For anthropometric variables, body mass, stature, arm span and the hand surface area were measured. The in-water force (16-24%) and performance (8%) improved over the competitive season with significant changes in the first macrocycle. The stroke index was the only kinematic variable that changed between M1 and M4 (12.7%), accompanied by a higher asymmetric motion later in the season. A time effect was found in the stature (p < 0.001, ηp 2 = 0.71), the arm span (p < 0.001, ηp 2 = 0.79), and the hand surface area (D = p < 0.001, ηp 2 = 0.63; ND = p < 0.001, ηp 2 = 0.666). Swimming performance showed associations with in-water force, stroke efficiency and anthropometric features in all time points of the season. Thus, the natural anthropometric growth experienced over the season may translate into a more efficient swimming pattern with greater in-water forces that can enhance performance.

Oxygen uptake kinetics and biological age in relation to pulling force and 400-m front crawl performance in young swimmers

Background: The study aimed to assess differences in the biological age (BA) of 13-year-old swimmers and show their ability, as biologically younger-late mature or older-early mature, to develop fast 60-s oxygen uptake (V ˙ O 2 ) kinetics and tethered swimming strength. Furthermore, the interplay between swimming strength, V ˙ O 2 , and 400-m front crawl race performance was examined. Methods: The study involved 36 competitive young male swimmers (metrical age: 12.9 ± 0.56 years). Depending on BA examination, the group was divided into early-mature (BA: 15.8 ± 1.18 years, n = 13) and late-mature (BA: 12.9 ± 0.60 years, n = 23) participants, especially for the purpose of comparing tethered swimming indices, i.e., average values of force (F ave) and V ˙ O 2 (breath-by-breath analysis) kinetic indices, measured simultaneously in 1-min tethered front crawl swimming. From the 400-m racing stroke rate, stroke length kinematics was retrieved. Results: In the 1-min tethered front crawl test, early-mature swimmers obtained higher results of absolute values of V ˙ O 2 and F ave. Conversely, when V ˙ O 2 was present relatively to body mass and pulling force (in ml∙min-1∙kg-1∙N-1), late-mature swimmers showed higher O 2 relative usage. Late-mature swimmers generally exhibited a slower increase in V ˙ O 2 during the first 30 s of 60 s. V ˙ O 2 , F ave, BA, and basic swimming kinematic stroke length were significantly interrelated and influenced 400-m swimming performance. Conclusion: The 1-min tethered swimming test revealed significant differences in the homogeneous calendar age/heterogeneous BA group of swimmers. These were distinguished by the higher level of V ˙ O 2 kinetics and pulling force in early-mature individuals and lower efficiency per unit of body mass per unit of force aerobic system in late-mature peers. The higher V ˙ O 2 kinetics and tethered swimming force were further translated into 400-m front crawl speed and stroke length kinematics.

Associations among sleep, hematologic profile, and aerobic and anerobic capacity of young swimmers: A complex network approach

Although the link between sleep and hematological parameters is well-described, it is unclear how this integration affects the swimmer’s performance. The parameters derived from the non-invasive critical velocity protocol have been extensively used to evaluate these athletes, especially the aerobic capacity (critical velocity—CV) and the anaerobic work capacity (AWC). Thus, this study applied the complex network model to verify the influence of sleep and hematological variables on the CV and AWC of young swimmers. Thirty-eight swimmers (male, n = 20; female, n = 18) completed five experimental evaluations. Initially, the athletes attended the laboratory facilities for venous blood collection, anthropometric measurements, and application of sleep questionnaires. Over the 4 subsequent days, athletes performed randomized maximal efforts on distances of 100, 200, 400, and 800-m. The aerobic and anerobic parameters were determined by linear function between distance vs. time, where CV relates to the slope of regression and AWC to y-intercept. Weighted but untargeted networks were generated based on significant (p < 0.05) correlations among variables regardless of the correlation coefficient. Betweenness and eigenvector metrics were used to highlight the more important nodes inside the complex network. Regardless of the centrality metric, basophils and red blood cells appeared as influential nodes in the networks with AWC or CV as targets. The role of other hematologic components was also revealed in these metrics, along with sleep total time. Overall, these results trigger new discussion on the influence of sleep and hematologic profile on the swimmer’s performance, and the relationships presented by this targeted complex network can be an important tool throughout the athlete’s development.