Search Results (32)

Background/Objectives:Training periodization is fundamental to optimizing athletic performance, with carbohydrate metabolism playing a critical role in supporting high-intensity efforts by facilitating muscle glycogen resynthesis. Recent studies suggest that high carbohydrate diets and high molecular weight carbohydrate (HMWC) supplementation can improve both endurance and anaerobic performance, while potentially influencing oxidative stress. This study investigates the effects of a high carbohydrate diet combined with HMWC supplementation on anaerobic performance and oxidative stress markers in elite swimmers. Methods: Eight national-level swimmers (tier 3–4) completed a three-day training microcycle with dietary interventions. Anaerobic capacity was assessed using Wingate tests for upper and lower limbs, while swimming performance was evaluated through an 8 × 100 m exercise protocol. The study was conducted using a one group quasi-experimental design with a pre-test/post-test structure, with participants acting as their own controls. Baseline measurements were taken prior to the intervention, followed by the administration of the high carbohydrate diet and HMWC supplementation. Post-intervention assessments were performed using the same test protocols to assess changes in performance and oxidative stress markers (such as GSH, CK, MDA, FRAP), which were determined by ELISA. The samples were stored at −80 °C until the evaluations. STATISTICA 5.0 (StatSoft, Inc., 1995) was used for statistical analysis of the obtained results. Results: The obtained results demonstrated significant improvements in peak power output for the lower limbs following supplementation (p < 0.001) and a reduced time to peak power for the upper limbs (p < 0.001). Additionally, velocity during the final swimming segments increased significantly following the intervention (p < 0.001). However, no notable changes were observed in antioxidant enzyme activity (SOD, CAT, GPx, GR) or low molecular weight antioxidants, suggesting a potential ceiling effect in redox adaptations. Lipid peroxidation, measured by MDA levels, increased post-supplementation (p < 0.05), indicating oxidative stress associated with high-intensity training and supplementation. Conclusions: The findings underscore the efficacy of combined dietary strategies with HMWC in enhancing anaerobic performance in swimming, while highlighting the necessity for further exploration of oxidative stress dynamics. Full article

Early life stages are pivotal to the functioning and resilience of ecological systems, displaying heightened vulnerability to environmental changes and exposure to contaminants. Octocrylene (OC), an organic ultraviolet (UV) filter, and its breakdown product benzophenone (BP) are commonly found in aquatic environments, but their impact on keystone processes determining the success or failure of the early life stages of marine organisms remains underexplored. This study aims to assess the impacts of OC and BP at environmentally realistic concentrations (1, 10, and 100 µg.L⁻¹), over a 24 h exposure period, on larvae of the Pacific oyster (Magallana gigas). A multiparametric approach was employed, examining DNA integrity, embryo–larval development and swimming velocity. The results showed that DNA integrity and swimming velocity were not affected by OC or BP; however, both compounds increased developmental abnormalities in D-shaped larvae in all concentrations tested. Considering the robustness of morphological parameters, often assumed as irreversible, and their critical influence on larvae survival, these findings suggest that environmentally relevant concentrations of OC and BP may threaten the success of oyster larvae, potentially impacting the population’s long-term stability and, ultimately, raising ecological health issues. Full article

Objectives: This study aims to determine the propulsive force and effective arm area contributed by the propulsion through the dynamic balance (power balance) between drag and propulsive power in swimming crawl performance. Methods: Ten male swimmers participated in the study. The athletes conducted the crawl trials at a constant velocity using only the upper limbs. Data were collected using a Spectro instrument to measure the drag and 3D video analysis for kinematic of upper limbs movement. Results: The power balance was confirmed through the Bland–Altman estimation (estimated bias 8.5) and was also demonstrated by a one-way analysis of variance that does not show statistical differences. Subsequently, by applying the power balance, the effective propulsive area could be estimated. The result shows an increase of ~8.5% over the value at the hand area used to verify the power balance. This value appears to be attributable to a percentage of the forearm area to propulsive action. Conclusions: This information will allow athletes and coaches to constantly monitor the propulsive force and power, providing useful data on arm movement and swimming technique. Indeed, deeper knowledge about the athlete’s swimming technique can reduce the possibility of suffering micro-traumas in the elbows and shoulders. Full article

Flow velocity is a key environmental factor that affects the behavioral strategies and physiological homeostasis of fish. To study the effects of flow velocity on the behavioral changes and blood physiology of the yellow croaker, the behavioral patterns of yellow croakers in response to flow velocity stress were obtained by analyzing changes in tail wagging frequency and amplitude. Differences in blood glucose, lactate, and cortisol were compared to determine their appropriate flow rate ranges. The juvenile stage of the large yellow croaker is crucial, as environmental changes can affect the physiology of fish. Therefore, juvenile yellow croakers were selected as the experimental subjects for this study. Twenty-four healthy and uniformly sized large yellow croakers with body weights of (90.26 ± 9.91) g and body lengths of (19.91 ± 0.69) cm were randomly assigned to one control group and three experimental groups, with five fish in each group. The experimental group was set with three flow rates, namely 1 bl/s (20 cm/s), 2 bl/s (40 cm/s), and 3 bl/s (60 cm/s), with a flow rate stress duration of 1 h. The results showed that: (1) Under different flow velocities, the fish exhibited different tail wagging patterns. At low flow velocities, their tail fins exhibited a “C”-shaped swing, while at high flow velocities, their bodies exhibited an “S”-shaped swing. (2) Oscillation frequency and amplitude both increased with increasing flow velocity. At a flow velocity of 2 bl/s, the oscillation frequency significantly increased. When the flow velocity reached 3 bl/s, the oscillation amplitude significantly increased (p < 0.05). (3) Blood physiology showed significant changes with increased flow rate, and blood glucose content continuously decreased with increased flow rate, significantly decreasing at a flow rate of 2 bl/s (p < 0.05). Lactic acid and cortisol both increased with increasing flow rate, and significantly increased at a flow rate of 3 bl/s (p < 0.05). In summary, under high-flow velocity stress, significant changes occurred in the behavior and physiology of large yellow croakers, which were consistent with physiological changes in the blood. A flow rate higher than 2 bl/s can lead to intense swimming behavior, decreased blood sugar concentration, and increased lactate accumulation and stress levels. Therefore, the short-term tolerance of yellow croakers is 2 bl/s, and a flow rate of 1 bl/s is more suitable. Full article

The underwater phase (UP) is highly important for overall swimming performance in most swimming events. However, the metabolic effects of the prolonged UP remain unclear. The purpose of this cross-sectional study was to compare the blood lactate response to submaximal front-crawl swimming with short and extended UP. Twelve (four females) junior competitive swimmers (aged 15.4 (1.4) years) undertook 200 m front-crawl swim trials in a 25 m pool at a pre-determined “anaerobic threshold” velocity on two occasions using short (<5 m) and extended (12.5 m) UP after each turn. Pacing and total time were ensured to be identical between the trials. Capillary blood lactate response was measured. Testing for 25 m swim time with <5 m and 12.5 m UP was conducted on a separate occasion. When athletes undertook and extended UP after each propulsion from the wall, their post-exercise blood lactate concentration reached 7.9 (2.1) mmol/L, more than two times higher than the response to trial with short UP (p < 0.001). All-out 25 m swimming with <5 m or 12.5 m UP disclosed no difference in locomotion velocity (p > 0.05). In conclusion, extending UP of submaximal front-crawl swimming close to maximally allowed during the races substantially increases blood lactate accumulation, i.e., increases the reliance on anaerobic metabolism. Therefore, extended UP is most likely counterproductive for the performance in long-distance swimming, at least for the athletes with a FINA score of <800. On the other hand, the extension of UP could be an effective strategy to train ‘lactate tolerance’, lactate shuttling, removal, and recycling. Full article

The classical kinematic variables in swimming are based on the calculation of mean values. Stroke steadiness determines the relationship between the duration of all consecutive strokes throughout a test. The aims of the current investigation were to examine differences in stroke-to-stroke steadiness according to swimmers’ performance level on both body sides (breathing and non-breathing) and to analyse the interrelationship with kinematics during a 100 m front-crawl test. Thirty-two young, experienced swimmers voluntarily participated in the present study and were divided into two groups, national level (n = 15) and local level (n = 17), according to their competitive status within the national age-rankings. All participants performed a 100 m maximal test in a 50 m pool where they were laterally recorded. Kinematic variables such as mean velocity, stroke rate, stroke length, and stroke index, as well as long-term steadiness and short-term steadiness, were calculated. The two 50 m sections were analysed independently. Significant differences were observed between the two groups in the classical kinematic variables and in stroke steadiness (p < 0.05). In addition, stroke steadiness showed moderately high correlations with velocity (r = [−0.61–(−0.749)]) and stroke index (r = [−0.356–(−0.582)]). Maintaining a more stable inter-stroke period appears to be a determinant of performance in young, high-level national swimmers. Full article

This study aimed to identify the relationship between dryland tests and swimming performance in elite Paralympic swimmers. Fifteen competitive swimmers (age: 27.4 ± 5.4 years, height: 1.70 ± 6.8 m, body mass: 67.9 ± 9.2 kg; 9 males, 6 females) performed a lat pull-down and a bench press incremental load test to determine maximum power (Pmax), the strength corresponding to maximum power (F@Pmax), and the barbell velocity corresponding to maximum power (V@Pmax) from the force–velocity and power–velocity profiles. These outcomes were also normalized by the athlete’s body mass. Swimming performance was carried out from the best result in a 100 m freestyle race registered during an international competition. Lat pull-down F@Pmax was significantly associated with 100 m freestyle chronometric time (ρ = −0.56, p < 0.05), and lat pull-down V@Pmax presented a relationship with mean swimming velocity (ρ = 0.71, p < 0.01). Similarly, bench press F@Pmax and the normalized F@Pmax were significantly related to the mean swimming velocity (ρ = −0.51, ρ = −0.62, p < 0.05). Stepwise multiple regression showed that lat pull-down V@Pmax, bench press normF@Pmax, and V@Pmax accounted for 40.6%, 42.3%, and 65.8% (p < 0.05) of the mean swimming velocity variance. These preliminary results highlighted that simple dryland tests, although with a moderate relationship, are significantly associated with 100 m freestyle swimming performance in elite Paralympic swimmers. Full article

To ensure optimal feed intake, growth, and general fish health in aquaculture sea cages, interactions between drivers that affect oxygen conditions need to be understood. The main drivers are oxygen consumption and water exchange, caused by flow through the cage. Swimming energetics in rainbow trout (Oncorhynchus mykiss) in normoxia and hypoxia at 10, 15, and 20 °C were determined. Using the determinations, a conceptual model of oxygen conditions within sea cages was created. By applying the model to a case study, results show that with a temperature increase of 10 °C, oxygen concentration will decrease three times faster. To maintain optimal oxygen concentration within the cage, the flow velocity must be increased by a factor of 3.7. The model is highly relevant for current farms since the model predictions can explain why and when suboptimal conditions occur within the cages. Using the same method, the model can be used to estimate the suitability of potential new aquaculture sites. Full article

Vortex rock weirs (VRW) are often used in natural channel design applications to maintain channel form and function, provide physical channel stability, and enhance aquatic habitats. A balanced approach is required to address (often) conflicting goals of VRWs, which include providing erosion protection and grade control while facilitating fish passage for target species. This research evaluated a sequence of modified VRWs in a small-scale watercourse in Southern Ontario, Canada. To determine passage suitability for the target fish species, the water level, water temperature, and channel geometries at 10 VRWs and 11 adjacent pools were monitored under different water level conditions. The structural dimensions and velocity at each VRW were compared to the burst swim speed of local small-bodied fish species to determine fish passage suitability and identify the best practices for VRW design and construction. The results concluded that VRWs provided suitable passage for small-bodied fish species through gap and over-weir flow pathways, particularly during low water level conditions. Further, appropriate design considerations based on the VRW gradient, VRW width, keystone size, and pool length contributed to 100% fish ‘passability’ under all water level conditions. The methodology is provided for predicting the velocity and small-bodied fish passage suitability through VRWs, informing the best practices for VRW design and construction while balancing the requirements for channel stability and fish passage, and contributing to fish population management strategies. Full article

Evidence on the role of propulsion compared to drag in swimming, based on experimental settings, is still lacking. However, higher levels of propulsion seem to lead to faster swimming velocities. The aim of this study was to understand the variation in a set of kinematic and kinetic variables between two swimming sections and their relationship to swimming velocity. The sample consisted of 15 young adult recreational swimmers (8 males: 20.84 ± 2.03 years; 7 females: 20.13 ± 1.90 years). Maximum swimming velocity and a set of kinematic and kinetic variables were measured during two consecutive sections of the swimming pool. Differences between sections were measured and the determinants of swimming velocity were analyzed. Swimming velocity, propulsive force, and the other kinematic and kinetic variables did not change significantly (p < 0.05) between sections (only the intra-cyclic fluctuation of swimming velocity decreased significantly, p = 0.005). The modeling identified the propulsive force, stroke length, and active drag coefficient as the determinants of swimming velocity. Swimming velocity was determined by the interaction of kinematic and kinetic variables, specifically propulsive force and active drag coefficient. Full article

A trend in large yellow croaker (Larimichthys crocea) aquaculture is to establish production sites suitable for extreme weather conditions. However, continuous and strong currents can harm fish welfare. To determine a suitable site location, the swimming ability of large yellow croakers must be assessed. This study aims to provide novel insights into the physiological characteristics of large yellow croaker swimming and a reference for fishing and cage site selection. Currently, research on large yellow croakers has focused on behavior analysis. Herein, we investigate the effects of swimming on large yellow croakers’ metabolites by examining the preferred speed of the group and the sustained swimming ability of single-tailed fish. We evaluated factors that influence the large yellow croaker’s swimming fatigue by quantifying the metabolite contents and constructing a sustained swimming model. The results showed that large yellow croaker populations tend to grow in low-velocity environments, similar to their traditional habitat. The samples were taken at different swimming times at a flow velocity of 0.35 m/s. According to the results of the metabolite content analysis, blood glucose levels are closely associated with the swimming ability in large yellow croakers. The content of liver glycogen, which regulates blood glucose concentration, decreased in a certain linear relationship. The sustained swimming model of the large yellow croaker was constructed according to the changes in liver glycogen content. Based on our findings, we recommend the following: (1) for large yellow croakers with a size of approximately 13.5 cm (approximately 1 year old), the water velocity inside the cage should not exceed 2.6 BL/s; (2) the concentration of liver glycogen limits the sustained swimming ability of the large yellow croaker, providing a reference for studying the swimming ability of other fish. Full article

Race analysis performed by faster and slower swimmers enables the definition of effective strategies for carrying out the competition. Until now, measurements of this type were mainly conducted among top-level athletes. The aim of the study was to determine the differences in swimming technique in sprint races between faster (FS) and slower (SS) regional-level swimmers. The performance of 33 swimmers (mean FINA points = 449) competing in 50 m and 100 m freestyle races was analysed. To determine the velocity (v), stroke rate (SR), stroke length (SL), and stroke index (SI), races were recorded with the use of cameras. Using the Student’s t-test and Mann–Whitney U test, the results were compared for two groups: FS (mean FINA points = 557) and SS (mean FINA points = 379). In the 100 m competition, differences between groups were noticed in v (1.70 and 1.51 m/s), SL (2.06 and 1.85 m), and SI (3.52 and 2.80 m²/s), while in the 50 m competition, they were noticed in v (1.95 and 1.73 m/s), SR (59.46 and 55.01 cycle/min), and SI (3.44 and 3.04 m²/s, respectively for the FS and SS groups). Adapting the technique to a shorter distance should be performed by increasing the frequency of movements. At the same time, the decrease in SL should be controlled. The indicator enabling the assessment of technical effectiveness, regardless of the distance, is the SI. The 50 and 100 m freestyle races require specific technical skills to be mastered. Therefore, the development of technique in swimmers should include its various variants. Full article

Background: Modern pentathlon includes horse riding, fencing, swimming, shooting and cross-country running. Events can last many hours during which the athletes face almost maximal energy and physiological demands, and fatigue. Early recognition and prevention of injuries and overuse syndromes can be achieved by refining the individual training loads. The purpose of the study was to determine which parameter could be the most accurate predictor of swimming working capacity determinants in pentathletes. Methods: Fourteen male pentathletes performed a continuous maximal incremental test in the swimming flume ergometer to measure peak oxygen uptake (VO₂peak), and five swimming tests in a 50 m swimming pool to detect critical velocity (CV); velocity at 2 and 4 mM·L⁻¹ of blood lactate (v2, v4) and energy cost (EC). Results: The 200 m swimming time was 2:18–2:32 m:s (340 FINA points). CV was 1.21 ± 0.04 m·s⁻¹, v2 was 1.14 ± 0.09 and v4 1.23 ± 0.08 m·s⁻¹. VO₂peak was 3540.1 ± 306.2 mL·min⁻¹ or 48.8 ± 4.6 mL·kg⁻¹·min⁻¹. EC at 1.24 m·s⁻¹ was 45.7 ± 2.4 mL·kg⁻¹·min⁻¹. Our main finding was the large correlation of CV with 200 m swimming performance; Conclusions: Among all the protocols analysed, CV is the most predictive and discriminative of individual swimming performance in this group of pentathletes. It appears as the most suitable test to constantly refine their swimming training loads for both performance enhancement and health promotion. Full article

The main aim of this study was to compare the performance over different distances, the critical velocity (CV), and plasma acylcarnitines/amino acids of male and female adolescent swimmers. Moreover, we applied the complex network approach to identify which molecules are associated with athletes’ performances. On the first day under a controlled environment, blood samples were collected after 12 h of overnight fasting. Performance trials (100, 200, 400, and 800-m) were randomly performed in the subsequent four days in a swimming pool, and CV was determined by linear distance versus time mathematical function. Metabolomic analyses were carried out on a triple quadrupole mass spectrometer performing electrospray ionization in the positive ionization mode. No difference was observed between the performance of male and female swimmers. Except for 200-m distance (p = 0.08), plasma tyrosine was positively and significantly associated with the female times during the trials (100-m, p = 0.04; 400-m, p = 0.04; 800-m, p = 0.02), and inversely associated with the CV (p = 0.02). The complex network approach showed that glycine (0.406), glutamine (0.400), arginine (0.335), free carnitine (0.355), tryptophan (0.289), and histidine (0.271) were the most influential nodes to reach tyrosine. These results revealed a thread that must be explored in further randomized/controlled designs, improving the knowledge surrounding nutrition and the performance of adolescent swimmers. Full article

Over the last 50 years, sperm competition has become increasingly recognised as a potent evolutionary force shaping male ejaculate traits. One such trait is sperm swimming speed, with faster sperm associated with increased fertilisation success in some species. Consequently, sperm are often thought to have evolved to be longer in order to facilitate faster movement. However, despite the intrinsic appeal of this argument, sperm operate in a different biophysical environment than we are used to, and instead increasing length may not necessarily be associated with higher velocity. Here, we test four predictive models (ConstantPower Density, Constant Speed, Constant Power Transfer, Constant Force) of the relationship between sperm length and speed. We collated published data on sperm morphology and velocity from 141 animal species, tested for structural clustering of sperm morphology and then compared the model predictions across all morphologically similar sperm clusters. Within four of five morphological clusters of sperm, we did not find a significant positive relationship between total sperm length and velocity. Instead, in four morphological sperm clusters we found evidence for the Constant Speed model, which predicts that power output is determined by the flagellum and so is proportional to flagellum length. Our results show the relationship between sperm morphology (size, width) and swimming speed is complex and that traditional models do not capture the biophysical interactions involved. Future work therefore needs to incorporate not only a better understanding of how sperm operate in the microfluid environment, but also the importance of fertilising environment, i.e., internal and external fertilisers. The microenvironment in which sperm operate is of critical importance in shaping the relationship between sperm length and form and sperm swimming speed. Full article