Continuous Swimming Research Articles

A Study on Buoyancy Maintenance Time and Underwater Weight According to Changes in Lying-Down Posture During Coastal Safety Education

Kim, Y.-S.; Ryu, J.-H., and Lee, H.-T, 2021. A study on buoyancy maintenance time and underwater weight according to changes in lying-down posture during coastal safety education. In: Lee, J.L.; Suh, K.-S.; Lee, B.; Shin, S., and Lee, J. (eds.), Crisis and Integrated Management for Coastal and Marine Safety. Journal of Coastal Research, Special Issue No. 114, pp. 619–622. Coconut Creek (Florida), ISSN 0749-0208. In this research, an experiment was performed to calculate body weight data and mass data for the subject's supine position using a three-dimensional image analysis program and an underwater weighing machine. This is to raise people's awareness of maritime safety and to revise the guidelines for maritime safety education by preparing institutional policies. First, the buoyancy retention time according to the change in lying down posture was the longest in P1(head-up), and in the order of P2(horizontal) and P3(attention) with statistically significant difference. Second, the change in body weight (buoyancy) according to the change of the lying down position was found to be the heaviest in P3, followed by P2 and P1 with significant difference. Summarizing the results of this study, the best way to maintain the buoyancy according to the change in lying down position during survival swimming is P1 that allows the body to float on the surface for the longest time. It also showed the heaviest underwater weight at P3, so it was found that incorrect upper body stance during survival swimming could affect buoyancy, survival rate. Lastly, even a person who is proficient in swimming has a very limited survival time at low temperatures, so it is considered that the above-mentioned efficient floating method and continuous swimming and application in education are necessary.

Muscular adaptations in swimming scale worms (Polynoidae, Annelida).

Annelids are predominantly found along with the seafloor, but over time have colonized a vast diversity of habitats, such as the water column, where different modes of locomotion are necessary. Yet, little is known about their potential muscular adaptation to the continuous swimming behaviour required in the water column. The musculature and motility were examined for five scale worm species of Polynoidae (Aphroditiformia, Annelida) found in shallow waters, deep sea or caves and which exhibit crawling, occasional swimming or continuous swimming, respectively. Their parapodial musculature was reconstructed using microCT and computational three-dimensional analyses, and the muscular functions were interpreted from video recordings of their locomotion. Since most benthic scale worms are able to swim for short distances using body and parapodial muscle movements, suitable musculature for swimming is already present. Our results indicate that rather than rearrangements or addition of muscles, a shift to a pelagic lifestyle is mainly accompanied by structural loss of muscle bundles and density, as well as elongation of extrinsic dorsal and ventral parapodial muscles. Our study documents clear differences in locomotion and musculature among closely related annelids with different lifestyles as well as points to myoanatomical adaptations for accessing the water column.

Changes in mitochondrial biogenesis and fatty liver indicators in rat following continuous and high intensity interval training.

Oxidative stress and mitochondrial dysfunction can be tracked down in most liver diseases like non-alcoholic fatty liver disease (NAFLD). The most recommended preventative method is lifestyle modification, especially exercise. The aim of this study was the investigation of changes in the indexes of mitochondrial biogenesis and fatty liver indicators in rat following continuous and high intensity interval training. Thirty healthy male rats were divided into three control (C=10), Continuous swimming training (CT=10) and High intensity interval swimming training groups (HIIT=10). The training groups performed their specific exercises 5 days a week for 8 weeks. 24 h after the last training session in order to prepare the serum, a blood sample was taken from the left ventricle of the rats. In addition, liver tissue was extracted and the SIRT3, PGC-1α, GSH:GSSG, MDA, LDL, HDL, LDL:HDL, TG, TC, AST, ALT and FBS variables were measured by ELISA and analysis of blood biochemistry. Continuous training (CT) increased the levels of PGC-1α, SIRT3 and significantly reduced LDL, LDL:HDL, TG and FBS (P<0.05) levels. High-intensity interval training (HIIT) caused a significant increase in SIRT3 and a significant decrease in FBS (P<0.05) levels. Adaptations resulting from further aerobic exercise can increase mitochondrial biogenesis factors such as PGC-1α and SIRT3 in hepatocytes, improve this process in hepatocytes, and ultimately improve the fatty liver markers. Therefore, CT may be more effective than HIIT in preventing fatty liver disease.

Body-caudal fin fish-inspired self-propulsion study on burst-and-coast and continuous swimming of a hydrofoil model

The present study examines the energy efficiency of self-propelled hydrofoils for various modes and kinematics of swimming adopted by various body-caudal fin fish. In particular, this work considers the intermittent burst-and-coast (B&amp;C) and continuous swimming modes, and examines the effect of the undulating and/or pitching swimming kinematics, adopted by the undulating body of anguilliform fish and pitching caudal fin of carangiform and thunniform fish. Notably, B&amp;C swimming is adopted in nature mostly by the latter class but rarely by the former. This fact forms the basis of our study on the hydrodynamics and propulsion performance for both classes of fish-inspired swimming using a NACA0012 hydrofoil model. This analysis explores a large parameter space covering undulation wavelength, 0.8≤λ*&amp;lt;∞, Reynolds number, 50≤Ref≤1500, and duty cycle (DC), 0.1≤DC≤1, with the DC representing the fraction of time in B&amp;C swimming. The fluid–structure dynamics-based vortex-shedding-process is investigated, where B&amp;C swimming results in either an asymmetric reverse von Karman (RVK) or forward von Karman vortex street, rather than a symmetric RVK vortex street observed during continuous swimming. It is demonstrated that the B&amp;C swimming results in an energy saving, although there is a concomitant increase in the travel time. Moreover, our results show that B&amp;C swimming is effective for carangiform and thunniform tail-like kinematics but not for anguilliform body-like kinematics of the hydrofoil. Thus, the predictions are consistent with the observed swimming behavior adopted by a fish in nature and provide input into the efficient design of unmanned underwater vehicles.

Paleoecological and biomechanical inferences regarding the paleoichthyofauna of the Romualdo Formation, Aptian-Albian of the Araripe Basin, state of Pernambuco, northeastern Brazil

The Romualdo Formation, Aptian-Albian of the Araripe Basin, is known for the extraordinary preservation of its paleoichthyofauna. The majority of the studies performed on the basin are descriptive, so this study aims to analyze morphological adaptations in the paleoichthyofauna of the Romualdo Formation, seeking to understand how they influenced the life habits of fishes. To conduct the paleoecological study, 117 specimens were selected among 13 different taxa and used for the investigation of types of dentition, mouth orientation, and body morphology. A cluster analysis was carried out using morphometric data of body morphology, resulting in three groups based on the similarity index among the species. The morphology of most of the paleoichthyofauna, like Rhacolepis buccalis and Vinctifer comptoni, was adapted to swimming in high-energy environments and continuous swimming. Others, such as Araripelepidotes temnurus, presented a morphology adapted to surviving in low-energy environments, and few, like Brannerion sp. and Neoproscinetes penalvai, could perform maneuverability moves due to a deep, laterally flattened body and well-developed fins. The mouth orientation, as well as the body morphology, was of great importance to the inferences about the living zone and feeding habits of the fishes, suggesting that most inhabited the middle of the water column and were generalists regarding their feeding zone. Moreover, the types of dentition or lack thereof helped to infer food diversity and a possible food web. Therefore, the ecomorphological attributes showed some degree of morphological variations in the paleoichthyofauna, reflecting different swimming habits in environments of varied energy. The study also revealed a range of explored food resources, and the association among the fishes allowed the proposition of a rather complex food web.

BACKSTROKE TEACHING METHODS IN HEALTHY CHILDREN WITH RESIDUAL PRIMITIVE REFLEXES

There are studies suggesting that primitive reflexes can remain active in healthy children. Formal backstroke teaching is a part of many aquatic curriculum program. Even though the links with a problem during swimming learning with retained primitive reflexes were mentioned, there are no studies about effect of different backstroke teaching methods in healthy children with residual primitive reflexes. Aim of the study is to define the effect of teaching methods for backstroke in healthy children with residual primitive reflexes. Subjects: 6-7 years old healthy children with residual primitive reflexes. Methods: A part practice backstroke teaching method for the first group (12 children) has been focused on teaching of separate components (leg kicks, arm pulls, and breathing) before fitting them together, while another 12 participants in second group learnt backstroke separate components of arm-to-leg integration before combining them together inside of cycle. After 12 weeks of practice backstroke proficiency and heart rate during maximal continuous backstroke swimming were analyzed. The obtained results show significant differences between the two groups. The results of the second group are linked with better backstroke proficiency, significantly longer swimming distance and lower heart rate during swimming.

Lactate Threshold Evaluation in Swimmers: The Importance of Age and Method.

The purpose of the study was to define the most appropriate method for the calculation of the speed corresponding to lactate threshold (sLT) in male swimmers. Eight boys and eight adolescents (age: 11.4±0.5 and 15.8±0.8 years) performed 7×200-m swimming front-crawl and after drawing the speed vs. lactate curve, the sLTs were calculated using five methods: i) the intersection of two linear regression lines, ii) visual inspection, iii) D-max, iv) D-max modified, v) intersection of combined linear and exponential regression lines. All methods were compared to the speed corresponding to maximal lactate steady state (sMLSS). Two to four 30-min efforts of continuous swimming at imposed constant pace were used for sMLSS calculation. In both groups, speed of D-max modified was similar to sMLSS (children, 1.061±0.073 vs. sMLSS: 1.071±0.072 m·s-1; p>0.05; effect size: ES=0.15, small; adolescents, 1.318±0.060 vs. sMLSS: 1.284±0.047 m·s-1; p>0.05; ES=0.64, medium). In adolescents, sLT calculated by intersection of two regression lines and by visual inspection presented medium ES (0.22-0.24) and were no different to sMLSS (1.296 ± 0.051, 1.295±0.053 m·s-1, p>0.05). When testing children, D-max modified is the most appropriate method to estimate sMLSS. The intersection of the linear regression lines and visual inspection are suggested for sMLSS determination in adolescents.

Morphological divergences as drivers of diet segregation between two sympatric species of Serrapinnus (Characidae: Cheirodontinae) in macrophyte stands in a neotropical floodplain lake

Abstract Diet and morphology of Serrapinnus notomelas and Serrapinnus sp.1 were investigated across ontogeny, as a way to elucidate the key elements linked to the resource partitioning (a main driver for species coexistence). Fish sampling was conducted monthly between October 2010 and March 2012. Individuals were captured, identified, and classified into juvenile or adult. Our results show ontogenetic and interspecific differences in feeding abilities and morphological traits. Differences in body shape (relative area of the dorsal fin, length of head, height of the caudal peduncle, the aspect ratio of the pectoral and pelvic fin) favored divergent swimming performances (more maneuverability in S. notomelas and continuous swimming to Serrapinnus sp.1). We also observed divergences in trophic apparatus traits and correlations with different diets. In this context, it is highlighted that understanding the relationship between morphology and diet can assist in elucidating the processes that permeate the coexistence between sympatric species, and between ontogenetic periods. Besides, the relevant contribution of the measures of the trophic apparatus (gill raker length, the number of teeth cuspids, and intestinal coefficient) in trophic segregation seems to be a strong evidence in favor of the proposed discriminatory and predictive capacities of these traits.

Hydrodynamic benefits of intermittent locomotion of a self-propelled flapping plate.

Intermittent locomotion is a widely used behavioral strategy for fish and birds to reduce the cost of movement. The intermittent locomotion performance of a self-propelled flapping plate is investigated numerically. Two intermittent swimming modes, namely, the multiple-tail-beat mode (MT mode) and the half-tail-beat mode (HT mode), as well as the continuous swimming mode (CT mode), are considered. Performance is evaluated from propulsive speed, efficiency, and cost of transport. The hydrodynamic performances of the intermittent modes are found to be better than the hydrodynamic performance of the CT mode when the bending stiffness K is moderate [i.e., K≈O(1)] and the duty cycle is not too small. For the two intermittent modes, the performance of the HT mode is better than that of the MT mode when K is small or moderate, while the situation is opposite when K is large. It is found that compared to the asymmetric wake of the MT mode, the symmetric wake of the HT mode is favorable to generate more thrust force and therefore achieve better performance. Besides, at moderate K, the largest bending deformation of the plate in the HT mode, as well as the large normal force, produces the largest thrust during the flapping. The present results can help us to better understand the intermittent locomotion of animals and may be helpful for bionic design.

Burst-and-coast swimming is not always energetically beneficial in fish (Hemigrammus bleheri)

Burst-and-coast swimming is an intermittent mode of locomotion used by various fish species. The intermittent gait has been associated with certain advantages such as stabilizing the visual field, improved sensing ability, and reduced energy expenditure. We investigate burst-coast swimming in rummy nose tetra fish (Hemigrammus bleheri) using a combination of experimental data and numerical simulations. The experiments were performed in a shallow water channel where the tetra fish swam against an imposed inflow. High speed video recordings of the fish were digitized to extract the undulatory kinematics at various swimming speeds. The kinematics data were then used in Navier–Stokes simulations to prescribe the undulatory motion for three-dimensional geometrical models of the fish. The resulting steady-state speeds of the simulated self-propelled swimmers agree well with the speeds observed experimentally. We examine the power requirements for various realistic swimming modes, which indicate that it is possible to use continuous swimming gaits that require considerably less mechanical energy than intermittent burst-coast modes at comparable speeds. The higher energetic cost of burst-coast swimming suggests that the primary purpose of intermittent swimming may not be to conserve energy, but it may instead be related to a combination of other functional aspects such as improved sensing and the likely existence of a minimum tail-beat frequency. Importantly, using sinusoidal traveling waves to generate intermittent and continuous kinematics, instead of using experiment-based kinematics, results in comparable power requirements for the two swimming modes.

The ontogeny of sea turtle hatchling swimming performance

AbstractSea turtle hatchlings experience high mortality rates during dispersal. To minimize time spent in predator-dense waters, hatchlings typically undergo a period of hyperactivity termed the ‘frenzy’, characterized by almost continuous swimming for ~24 h. Research has focused on swimming performance during the frenzy, but our understanding of changes in swimming performance post-frenzy is limited. Thus, we measured green turtle (Chelonia mydas) hatchling swimming performance during the frenzy and post-frenzy when the turtles were 4, 12 and 24 weeks old. Using load cells, we recorded thrust production, stroke rates and the time turtles spent performing various swimming gaits. We found that the proportion of time spent powerstroking and the thrust generation per powerstroke were the main determinants of overall swimming performance. Older, larger turtles generated more thrust per stroke, but the proportion of time spent powerstroking throughout the entire swimming trial did not differ among age groups. Hatchlings have been thought mainly to use currents to reach nursery foraging grounds, and our findings suggest that hatchling swimming might also play an important role in directing hatchlings to optimal nursery habitats, supporting recent studies. Additionally, turtle size is positively related to swimming performance in post-frenzy turtles, suggesting that faster-growing turtles might have fitness advantages over slower-growing turtles.

Influence of maturational status in the exercise-induced release of cardiac troponin T in healthy young swimmers

ObjectivesTo determine the influence of maturational status on the release of cardiac troponin T (cTnT) induced by a bout of 30min, high-intensity, continuous exercise. DesignQuasi-experimental, cross-sectional study. MethodsSeventy male, young, well trained swimmers (age range 7–18 years, training experience 1–11 years) were classified by maturational stages: Tanner stage I (n=14), II (n=15), III (n=15), IV (n=13), and V (n=13). Participants underwent a distance-trial of 30min continuous swimming, and cTnT was measured before, immediately after and 3h after exercise. Changes in cTnT over time were compared among groups, and associated with exercise load. ResultsBasal cTnT was higher in Tanner-V (3.8–8.1ng/L) compared with I (1.5–5.5ng/L, p<0.001), II (1.5–4.5ng/L, p<0.001) and III (1.5–6.8ng/L, p=0.003), and in IV (1.5–6.3ng/L) compared with II (p=0.036). Maximal elevations of cTnT from baseline were notable (p<0.001) and comparable among maturational stages (p=0.078). The upper reference limit for myocardial injury was exceeded in 35.7% of the participants, without differences among groups (p=0.18). Baseline cTnT correlated with participant characteristics, and maximal cTnT elevations from baseline with exercise internal load (%HRpeak, rs=0.34, p= 0.003; %HRmean, rs=0.28, p=0.02). ConclusionsMaturational status influences positively absolute pre- and post-exercise cTnT but not its elevation after a bout of 30min, high-intensity, continuous exercise.

Verifying Physiological and Biomechanical Parameters during Continuous Swimming at Speed Corresponding to Lactate Threshold.

The purpose of this study was to verify the physiological responses and biomechanical parameters measured during 30 min of continuous swimming (T30) at intensity corresponding to lactate threshold previously calculated by an intermittent progressively increasing speed test (7 × 200 m). Fourteen competitive swimmers (18.0 (2.5) years, 67.5 (8.8) kg, 174.5 (7.7) cm) performed a 7 × 200 m front crawl test. Blood lactate concentration (BL) and oxygen uptake (VO2) were determined after each 200 m repetition, while heart rate (HR), arm-stroke rate (SR), and arm-stroke length (SL) were measured during each 200 m repetition. Using the speed vs. lactate concentration curve, the speed at lactate threshold (sLT) and parameters corresponding to sLT were calculated (BL-sLT, VO2-sLT, HR-sLT, SR-sLT, and SL-sLT). In the following day, a T30 corresponding to sLT was performed and BL-T30, VO2-T30, HR-T30, SR-T30, and SL-T30 were measured after the 10th and 30th minute, and average values were used for comparison. VO2-sLT was no different compared to VO2-T30 (p > 0.05). BL-T30, HR-T30, and SR-T30 were higher, while SL-T30 was lower compared to BL-sLT, HR-sLT, SR-sLT, and SL-sLT (p < 0.05). Continuous swimming at speed corresponding to lactate threshold may not show the same physiological and biomechanical responses as those calculated by a progressively increasing speed test of 7 × 200 m.

Comparison of thermoregulation and physiological responses after swimming exercise according to age and swim cap material in women

This study aimed to determine the factors that affect body temperature changes and physiological responses during continuous swimming according to swim cap material. Subjects included 24 women in their 20s and 40s without any relevant medical histories. The distance of the swim exercise was set at 1500m, and was completed at a pace of 40seconds per 50m using the freestyle stroke. Body temperature, skin temperature, heart rate, lactate, rated perceived exertion (RPE), and thermal sensation were measured 30 min before exercise, every 10 min during exercise, immediately after 30 min of exercise, and 30 min after recovery. Body temperature demonstrated a significant interaction effect according to swim cap material and age based on swim time (p<0.05). Skin temperature demonstrated a significant difference according to swim time (p<0.05). Heart rate was significantly different according to swim exercise (p<0.001). Lactic acid demonstrated a significant difference according to swim time (p<0.001) and interaction effect (p<0.01). RPE demonstrated a significant difference according to swim time (p<0.001), and swim time according to age (p<0.01) and interaction effects (p<0.05). Finally, thermal sensation demonstrated a significant difference over time (p<0.001). In conclusion, wearing swim caps made from a light mesh material was excellent for heat dissipation and breathability, and reduced fatigue and improved exercise performance through temperature control.

Ontogenetic change in the amount and position of slow-oxidative myotomal muscle in relationship to regional endothermy in juvenile yellowfin tuna Thunnus albacares.

Myotomal slow-oxidative muscle (SM) powers continuous swimming and generates heat needed to maintain elevated locomotor muscle temperatures (regional endothermy) in tunas. This study describes how the amount and distribution of myotomal SM increases with fish size and age in juvenile yellowfin tuna Thunnus albacares in relationship to the development of regional endothermy. In T. albacares juveniles 40-74 mm fork length (LF ; n = 23) raised from fertilised eggs at the Inter-American Tropical Tuna Commission Achotines Laboratory in Panama and larger juveniles (118-344 mm LF ; n = 5) collected by hook and line off of Oahu, Hawaii, USA, SM was identified by histochemical staining for the mitochondrial enzyme succinic dehydrogenase or by colour (in the two largest individuals). The cross-sectional area of myotomal SM at 60% LF , a position with maximal percentage of SM in larger T. albacares, increased exponentially with LF . The percentage of total cross-sectional area composed of SM at 60% LF increased significantly with both LF and age, suggesting that SM growth occurs throughout the size range of T. albacares juveniles studied. In addition, the percentage of SM at 60% LF that is medial increased asymptotically with LF . The increases in amount of SM and medial SM, along with the development of the counter-current heat-exchanger blood vessels that retain heat, allow larger tuna juveniles to maintain elevated and relatively stable SM temperatures, facilitating range expansion into cooler waters.

Effect of swimming training on levels of asprosin, lipid profile, glucose and insulin resistance in rats with metabolic syndrome

BackgroundAsprosin is a novel biomarker that associated with type 2 diabetes mellitus. The aim of this study was to investigate the effects of continuous and interval swimming training on the asprosin, lipid profile, glucose concentration and insulin resistance serum levels of rats with metabolic syndrome. MethodsForty-eight male Wistar rats were randomly divided into two groups, standard diet (SD) and high-fat diet (HD), and received their respective diets for a period of 12 weeks without exercise stimuli. After this period, the animals were randomly divided into four groups (n = 8); normal control standard diet (NC), control (Ctr), continuous training (load 0–3% body mass, 5 d/wk, for 8 weeks, CT) and interval training (load 5–16% body mass, 5 d/wk, for 8 weeks, IT). The continuous and interval training consisted of a swimming exercise performed over eight weeks. ResultThe NC and trained groups showed lower values of total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL-C) and glucose concentration compared to Ctr group. Serum level of asprosin significantly decreased underlying CT and IT compared to NC and Ctr groups. No significant difference were observed between trained groups. ConclusionIt seems that both swimming training methodologies are shown to be effective in the serum levels of asprosin, lipid profile and glucose concentration in metabolic syndrome rats.

Large-Amplitude Intermittent Swimming in Viscous and Inviscid Flows

Recently, it was demonstrated in an inviscid flow that burst-and-coast or intermittent swimming can save energy when compared with continuous swimming and that the energy savings are maximized for large-amplitude pitching motions where flow separation is likely to occur. This paper examines the effects of flow separation on altering inviscid flow predictions. As such, viscous and inviscid flow simulations are presented of a hydrofoil pitching intermittently with large-amplitude motions. It is observed that leading-edge vortex formation and shedding in a viscous flow significantly alter the wake dynamics from the inviscid flow solutions where only trailing-edge shedding is modeled. Moreover, the inviscid flow solutions predict higher peak force production, lower cost of transport, and lower optimal duty cycles than the viscous flow solutions. Despite these differences, the trends in the force production and energetics seen in a viscous flow are well captured by the inviscid flow simulations. Importantly, both predict energy savings on the order of 10–30% for intermittent swimming, and the energy savings increase when the amplitude of motion is increased even when significant leading-edge separation occurs.

Endothermy in the smalleye opah (Lampris incognitus): A potential role for the uncoupling protein sarcolipin

Sarcolipin (SLN) is a small transmembrane protein that in mice has been shown to uncouple the calcium ATPase pump of the sarcoplasmic reticulum, resulting in heat production. Mice up-regulate expression of SLN in response to cold challenge. This thermoregulatory mechanism is characterized as non-shivering muscle-based thermogenesis (NST). The current study was conducted to determine if the endothermic fish species, the smalleye opah (Lampris incognitus), has higher levels of sln transcription in tissues thought to be the main source of endothermic heat, namely the red aerobic pectoral fin musculature, which powers continuous swimming in this species. A search of the draft assembly of the opah genome reveals a single sln gene that is 95% identical to the zebrafish sln ortholog at the amino acid level. Quantitative PCR (qPCR) using opah-specific sln shows significantly higher sln transcript levels in the dark red pectoral fin muscle compared to both the light red pectoral muscle and white axial muscle tissues. The high ratio of sln transcripts to CaATPase (serca1) transcripts suggests that opah may utilize a futile calcium cycling NST mechanism in the dark red pectoral fin muscle to generate heat.

Physiological Responses of Continuous and Intermittent Swimming at Critical Speed and Maximum Lactate Steady State in Children and Adolescent Swimmers.

Background: The purpose of this study was to compare physiological responses during continuous and intermittent swimming at intensity corresponding to critical speed (CS: slope of the distance vs. time relationship using 200 and 400-m tests) with maximal lactate steady state (MLSS) in children and adolescents. Methods: CS and the speed corresponding to MLSS (sMLSS) were calculated in ten male children (11.5 ± 0.4 years) and ten adolescents (15.8 ± 0.7 years). Blood lactate concentration (BL), oxygen uptake (O2), and heart rate (HR) at sMLSS were compared to intermittent (10 × 200-m) and continuous swimming corresponding to CS. Results: CS was similar to sMLSS in children (1.092 ± 0.071 vs. 1.083 ± 0.065 m·s−1; p = 0.12) and adolescents (1.315 ± 0.068 vs. 1.297 ± 0.056 m·s−1; p = 0.12). However, not all swimmers were able to complete 30 min at CS and BL was higher at the end of continuous swimming at CS compared to sMLSS (children: CS: 4.0 ± 1.8, sMLSS: 3.4 ± 1.5; adolescents: CS: 4.5 ± 2.3, sMLSS: 3.1 ± 0.8 mmol·L−1; p < 0.05). O2 and HR in continuous swimming at CS were not different compared to sMLSS (p > 0.05). BL, O2 and HR in 10 × 200-m were similar to sMLSS and no different between groups. Conclusion: Intermittent swimming at CS presents physiological responses similar to sMLSS. Metabolic responses of continuous swimming at CS may not correspond to MLSS in some children and adolescent swimmers.

Beneficial effects of maternal swimming during pregnancy on offspring metabolism when the father is obese.

We aimed to evaluate the impact of maternal exercise training on the offspring metabolism and body size caused by father obesity. C57BL/6 male 4-week-old mice were fed a high-fat diet (HF father) or control diet (C father), while equal age female mice were fed only a C diet and were separated into two groups: trained (T mother) and non-trained (NT mother), and at 12 weeks of age mice were mated. A continuous swimming protocol was applied for 10 weeks (before and during gestation), and offspring were followed since weaning until sacrifice (at 12 weeks of age). HF father, compared to C father, showed obesity, elevated total cholesterol (TC) and triglycerides (TG), and glucose intolerance. Both sexes HF/NT offspring showed hyperglycemia, glucose intolerance and high levels of TC and TG, without obesity. However, HF/T offspring showed data close to C/NT, demonstrating the beneficial effect of maternal exercise in the offspring of obese fathers.