Continuous Swimming Research Articles

The effects of six sprint interval training sessions on muscle oxygenation and swimming performance in untrained swimmers.

The current study examined the changes in muscle oxygenation values and swimming performance after six sessions of sprint interval training during a three-week period in untrained swimmers. Twelve swimmers of both genders (age: 23.5 ± 5.6yrs) executed the twice-weekly experimental training protocol (EXP, n = 12), consisting of a 4 × 50 m front-crawl swimming (repeated sprint training-RST) with maximal intensity, and 2 min of passive recovery in between, after a short in-water warm-up. The control group (CON, n = 9) performed a continuous swimming set (200 m) at 120 b pm-1, with the same weekly frequency. Performance times in two maximum swim trials (400 m: T400 and 50 m: T50), muscle oxygenation of the deltoid muscle (SmO2) immediately after T400 and T50, 1-min heart rate recovery (HRR1) after T400, T50, and swim strokes during both swim trials (S/T400, S/T50) were assessed. For the EXP group, T400 improved by 2.4 (p = 0.011). In contrast, T50 presented no significant improvement (1%, p > 0.05). SmO2 decreased at T400 (5.5%, p = 0.017) and increased at T50 (3.7%, p = 0.030). HRR1 improved after T400 (7.9%, p = 0.002), T50 (4.6%, p = 0.005) and RST (9.6%, p = 0.002). S/T400 and S/T50 remained relatively unchanged (p > 0.05). The CON group presented no significant changes in any of the variables examined. In conclusion, six sprint interval training sessions can improve aerobic capacity over a 3-week training period, as indicated by the enhanced T400 performance and the reduced HRR1 values, in previously trained swimmers. Finally, the sensitivity of the near-infrared spectroscopy method to detect short-term training-induced changes is highlighted.

A novel protocol for three-dimensional mapping of sand tiger shark (Carcharias taurus) enclosure use in aquaria: Implications for management.

This study investigated sand tiger shark (STS; Carcharias taurus) spatial use and exclusion in public aquarium enclosures using a novel protocol for three-dimensional mapping. Fifty-one STS were observed in 14 enclosures, and swimming pattern, depth, and location were recorded in ZooMonitor. Data were converted into quantitative, three-dimensional representations using ArcGIS® Pro v. 2.9. All observed STS except one swam in circular patterns, and 80% (n = 41) showed a directional swimming bias. Most STS (80%; n = 41) predominantly utilized the top two-thirds of the enclosures, though 83% (n = 34) of those had swimming obstructions in the bottom of the enclosure. Avoidance of obstructed areas, sections <7 m wide, as well as behavioral spatial separation, resulted in utilization of between 27% and 66% of available enclosure space. STS underutilized corners, pinch-points, and obstructed areas requiring abrupt directional changes and instead exhibited continual, unimpeded swimming patterns. In addition, this study found no relationship between directional swimming bias or use of smaller enclosure volumes and spinal deformity, a health issue affecting 26% of STS 10 years ago but now with an incidence of 6%. Using novel protocols for three-dimensional mapping and volume estimation, this study demonstrated that enclosures facilitating unimpeded, continuous swimming are most usable for STS and provides important information that will be useful for future enclosure design.

Both High-Intensity Interval and Moderate-Intensity Continuous Training Decrease Fetuin-A Levels in High Fat Diet Fed Male Rats

Background: Fetuin-A is a hepatokine that increases in obesity, and a high-fat diet (HFD) contributes to this condition. Obesity is characterized by increased body mass index (BMI) and is correlated to insulin resistance. This study aims to analyze the difference between High-Intensity Interval Training (HIIT) and Moderate-Intensity Continuous Training (MICT) on fetuin-A, insulin, fasting blood glucose (FBG) levels, and BMI in HFD-fed rats. Methods: Twenty-four male Wistar rats were divided into four groups: CD (standard diet), HFD (HFD only), HFD-IT (HFD and HIIT), and HFD-CT (HFD and MICT). HFD consisted of a standard diet with an additional 2 mL/200-gram body weight of lard oil daily. In the HFD-IT group, swimming was performed with a 9% body weight load with short duration and intermittent rest periods, while the HFD-CT group was given a 6% body weight load and continuous swimming. Swimming was conducted five days a week for four weeks. Fetuin-A and insulin levels were measured using enzyme-linked immunosorbent assay (ELISA) method, and FBG levels were measured using a glucometer. Results: Fetuin-A levels were significantly lower in the HFD-IT and HFD-CT groups compared to the HFD group (p&lt;0.05). The HFD-CT group had a significant decrease in FBG levels (p&lt;0.05), but the HFD-IT group did not. There were no differences in BMI and insulin levels between groups after four weeks of treatment (p&gt;0.05). Conclusion: HIIT and MICT have similar effectiveness in reducing fetuin-A levels. In addition, MICT also managed to reduce FBG levels. Keywords: interval training, continuous training, high-fat diet, fetuin-A, insulin, healthy lifestyle.

High speed underwater hydrogel robots with programmable motions powered by light

Stimuli-responsive shape-changing hydrogels are attractive candidates for use as underwater soft robots. The bottleneck lies in the low actuation speed inherently limited by the water diffusion between hydrogels and their surrounding environment. In addition, accessing complex motions is restricted by the material fabrication methods. Here we report a hitherto unknown mechanism to achieve high-speed and programmable actuations for a disulfide crosslinked thermally responsive hydrogel. The dynamic photo-activated disulfide bond exchange allows photo-mechanical programming to introduce spatio-selective network anisotropy. This gives rise to an actuation behavior dominated by thermally driven conformation change of the locally oriented polymer chains instead of the common mass-diffusion-based mechanism. With the incorporation of photothermal fillers, light-powered oscillation at frequencies as high as 1.7 Hz is realized. This, coupled with the versatility of the programming, allows access to robots with diverse high-speed motions including continuous swimming, step-wise walking, and rotating.

Effect of Swimming Training on Cardiac Morphological Factors, Apelin and Insulin like Growth Factor-1 in Male Wistar Rats

Introduction: Different training methods have cardioprotective effects. The aim of this study was to examine the potential protective impact of continuous and interval swimming training with weights on cardiac morphological factors and serum levels of Apelin and Insulin-like Growth Factor-1 in male Wistar rats.&#x0D; Methods: In this experimental study, 27 male rats divided randomly into the control (n=6), sham (n=5), interval (n=8) and endurance (n=8) groups. The endurance group swam for 12 weeks/5 days while swimming time increased incrementally. During the 12-week/4-day period, the interval group engaged in swimming exercises while gradually increasing the load and reducing the duration of rest. Apelin and Insulin like Growth Factor-1 concentration, heart weight and left ventricle weight were measured. One-way ANOVA was utilized and Tuckey-HSD test was used to point out the place of significance (α ≤ 0.05).&#x0D; Results: Findings showed that total heart weight in interval and endurance training compared to the control (P= 0.02 and P= 0.02 respectively) and sham (P= 0.02 and P= 0.02, respectively) significantly increased. Furthermore, the weight of the left ventricle showed a significant increase following endurance training in comparison to both the control (P= 0.02) and the sham groups (P= 0.02). Additionally, it was found to be significantly higher than the sham group following interval training. (P= 0.01). Apelin significantly increased in interval and endurance training compared to the control (P= 0.00 and P= 002 respectively) and sham groups (P= 0.02 and P= 0.04, respectively). Moreover, insulin like growth factor-1 significantly increased in interval and endurance training compared to the control (P= 0.01 and P= 0.01, respectively).&#x0D; Conclusion: It appears that a 12-week swimming training program, particularly in an interval format, can induce physiological hypertrophy in cardiac tissue and provide cardiac protective benefits through the upregulation of Insulin-like Growth Factor-1 and Apelin.

Intermittent vs. continuous swimming training on adipokines and pro-inflammatory cytokines in metabolic syndrome experimental model.

In this study, metabolic syndrome-affected ratswere studied to examine how intermittent and continuous swimming training influenced adipokines and pro-inflammatory cytokines. Forty-eight male Wistar rats were randomized inthis experimental study into four groups (n=8), including normal control (NC), metabolic syndrome (MS), continuous swimming training with metabolic syndrome (CT-MS: load 0-3% body mass, 5d/wk, for 8weeks), and intermittent swimming training with metabolic syndrome (IT-MS: load 5-16% body mass, 5d/wk, for 8weeks). The serum levels of metrnl, adipolin, irisin, leptin, TNF-α, and IL-6 were measured using the ELISA test. The IT-MS and NC groups exhibited significantly lower leptin concentrations than the CT-MS group (p=0.001). The irisin, meteorin, and adipolin serum levels increased significantly in CT-MS and IT relative to the NC and CT-MS groups (p=0.001), with the changes being more pronounced in the IT group (p=0.05). TNF-α and IL-6 were inclined in the CT-MS group compared with the other three groups (p=0.001), while IL-6 was increased in the IT group (p=0.024). Intermittent swimming is more effective thancontinuous swimming training in improving adipokines in rats with metabolic syndrome.

Effects of dietary lipid and air replenisher on the growth and lipid deposition of steelhead trout (Oncorhynchus mykiss) confined underwater

In this study, we investigated the effects of dietary lipids (DL) on the growth and lipid deposition of steelhead trout (Oncorhynchus mykiss) confined underwater using various equipment. Three diets formulated with 6%, 13%, and 20% DL (F6, F13, and F20) were fed to the fish. Fish (initial weight: 75.01 ± 1.36 g) in each dietary group were randomly cultured in three equipment groups: the control group; the submergence group, in which mesh and airstones were used to keep the experimental fish from the water surface; and the replenisher group, in which an air replenisher and airstones were utilized under the mesh. The results of this 70-day study showed that the growth and crude lipid content of the steelhead trout fish body increased significantly with increasing DL levels. No significant differences were observed in the liver among the different equipment groups, whereas the lipid contents in the muscle and the viscerosomatic index significantly decreased in the submerged group fed F20. The fitted curve analysis showed that the energy expenditure of continuous swimming and the success of replenishing the swim bladder may determine the strategy adopted by trout to cope with negative buoyancy. If the swim bladder was easily replenished, steelhead trout tended to convert excess energy into lipid stored in muscles, thereby reducing body density and maintaining neutral buoyancy. Otherwise, trout must burn lipid in their muscles to ensure energy supply to keep swimming for lift. We concluded that a high-lipid diet compensated for the loss of the energy used in resistance to negative buoyancy, and growth performance of steelhead trout improved.

Intermittent versus continuous swimming: An optimization tale

Intermittent swimming has been recognized as a strategy for fish to enhance their energetical efficiency. In this study, a hybrid computational fluid dynamic model is used to assess the swimming performance in intermittent swimming parametrically and quantitatively. The results show that the energetical performance of intermittent swimming can be better than that of continuous swimming, but also that an unoptimized intermittent gait may become very energetically expensive.

The Impact of Wetsuit Use on Swimming Performance, Physiology and Biomechanics: A Systematic Review

This systematic review aims to summarize the effects of wearing different types of wetsuits and swimsuits in front crawl swimming performance and physiological- and biomechanical-related variables. The Web of Science, PubMed, Scopus and the Proceedings of the International Symposium on Biomechanics and Medicine in Swimming databases were searched from inception to 25th March 2022. From the 1398 studies initially found, 26 studies were included in the review. The quality assessment and inter-rater reliability between researchers were conducted. The full body was the most studied wetsuit, with its use allowing 3.2–12.9% velocity increments in distances ranging from 25 to 1500 m, in incremental tests, in 5 and 30 min continuous swimming and in open water events. The sleeveless long vs. the full-body wetsuit led to a 400–800 m performance enhancement. Higher stroke rate, stroke length and stroke index were observed while using three different covered body part wetsuits vs. a regular swimsuit, with a lower energy cost being observed when swimming with the full-body wetsuit compared to a swimsuit. These findings provide useful information for coaches, swimmers and triathletes about the full-body and sleeveless long/short wetsuit use, since these three wetsuits allow improving swimming performance in different distances in diverse aquatic environments.

Internal vertebral morphology of bony fishes matches the mechanical demands of different environments.

Fishes have repeatedly evolved characteristic body shapes depending on how close they live to the substrate. Pelagic fishes live in open water and typically have narrow, streamlined body shapes; benthic and demersal fishes live close to the substrate; and demersal fishes often have deeper bodies. These shape differences are often associated with behavioral differences: pelagic fishes swim nearly constantly, demersal fishes tend to maneuver near the substrate, and benthic fishes often lie in wait on the substrate. We hypothesized that these morphological and behavioral differences would be reflected in the mechanical properties of the body, and specifically in vertebral column stiffness, because it is an attachment point for the locomotor musculature and a central axis for body bending. The vertebrae of bony fishes are composed of two cones connected by a foramen, which is filled by the notochord. Since the notochord is more flexible than bony vertebral centra, we predicted that pelagic fishes would have narrower foramina or shallower cones, leading to less notochordal material and a stiffer vertebral column which might support continuous swimming. In contrast, we predicted that benthic and demersal fishes would have more notochordal material, making the vertebral column more flexible for diverse behaviors in these species. We therefore examined vertebral morphology in 79 species using micro-computed tomography scans. Six vertebral features were measured including notochordal foramen diameter, centrum body length, and the cone angles and diameters for the anterior and posterior vertebral cones, along with body fineness. Using phylogenetic generalized least squares analyses, we found that benthic and pelagic species differed significantly, with larger foramina, shorter centra, and larger cones in benthic species. Thus, morphological differences in the internal shape of the vertebrae of fishes are consistent with a stiffer vertebral column in pelagic fishes and with a more flexible vertebral column in benthic species.

Time limit and V̇O2 kinetics at maximal aerobic velocity: Continuous vs. intermittent swimming trials.

The time sustained during exercise with oxygen uptake (V̇O2) reaching maximal rates (V̇O2peak) or near peak responses (i.e., above second ventilatory threshold [t@VT2) or 90% V̇O2peak (t@90%V̇O2peak)] is recognized as the training pace required to enhance aerobic power and exercise tolerance in the severe domain (time-limit, tLim). This study compared physiological and performance indexes during continuous and intermittent trials at maximal aerobic velocity (MAV) to analyze each exercise schedule, supporting their roles in conditioning planning. Twenty-two well-trained swimmers completed a discontinuous incremental step-test for V̇O2peak, VT2, and MAV assessments. Two other tests were performed in randomized order, to compare continuous (CT) vs. intermittent trials (IT100) at MAV until exhaustion, to determine peak oxygen uptake (Peak-V̇O2) and V̇O2 kinetics (V̇O2K). Distance and time variables were registered to determine the tLim, t@VT2, and t@90%V̇O2peak tests. Blood lactate concentration ([La−]) was analyzed, and rate of perceived exertion (RPE) was recorded. The tests were conducted using a breath-by-breath apparatus connected to a snorkel for pulmonary gas sampling, with pacing controlled by an underwater visual pacer. V̇O2peak (55.2 ± 5.6 ml·kg·min−1) was only reached in CT (100.7 ± 3.1 %V̇O2peak). In addition, high V̇O2 values were reached at IT100 (96.4 ± 4.2 %V̇O2peak). V̇O2peak was highly correlated with Peak-V̇O2 during CT (r = 0.95, p < 0.01) and IT100 (r = 0.91, p < 0.01). Compared with CT, the IT100 presented significantly higher values for tLim (1,013.6 ± 496.6 vs. 256.2 ± 60.3 s), distance (1,277.3 ± 638.1 vs. 315.9 ± 63.3 m), t@VT2 (448.1 ± 211.1 vs. 144.1 ± 78.8 s), and t@90%V̇O2peak (321.9 ± 208.7 vs. 127.5 ± 77.1 s). V̇O2K time constants (IT100: 25.9 ± 9.4 vs. CT: 26.5 ± 7.5 s) were correlated between tests (r = 0.76, p < 0.01). Between CT and IT100, tLim were not related, and RPE (8.9 ± 0.9 vs. 9.4 ± 0.8) and [La−] (7.8 ± 2.7 vs. 7.8 ± 2.8 mmol·l−1) did not differ between tests. MAV is suitable for planning swimming intensities requiring V̇O2peak rates, whatever the exercise schedule (continuous or intermittent). Therefore, the results suggest IT100 as a preferable training schedule rather than the CT for aerobic capacity training since IT100 presented a significantly higher tLim, t@VT2, and t@90%V̇O2peak (∼757, ∼304, and ∼194 s more, respectively), without differing regards to [La−] and RPE. The V̇O2K seemed not to influence tLim and times spent near V̇O2peak in both workout modes.

THE LINK BETWEEN HEART RATE VARIABILITY AND ENDURANCE IN SWIMMING

Heart rate variability is a relatively new measurement in sport that can predict sport performance. Unfortunately, it is underused because usually it is not simple to measure it. In the last years, because of the increase of the investment in sport, many companies tried to make different devices to make this measurement easier. In this study, for 21 days, 10 elite swimmers aged between 12 and 14 years old were observed. All the swimmers are experienced ones, being ranked in the first 2 places at Romanian National Championships in at least one swimming event. In this period, they performed 3 endurance tests, at a 10-day interval. The endurance test consisted of a 30 minutes continuous swimming at maximum speed, these tests being named T-30. Heart rate variability was measured in every morning, right before practice, on the swimming deck. For this measurement was used a very easy to use device, iThlete, a photoplethysmography which was attached to a mobile phone. The time needed for measurement is only 55 seconds and the value is very easy to interpret. The link between swimming endurance and the heart rate variability measurement was interpreted. The results showed us that heart rate variability influenced the results in swimming endurance with a p-value&lt;0,001.

Mitochondrial Biogenesis in Continuous vs High-intensity Interval Swimming

Mitochondrial Biogenesis in Continuous vs High-intensity Interval Swimming

A comparison of modelled serum cTnT and cTnI kinetics after 60 min swimming

Post-exercise elevations of cardiac troponin T (cTnT) and I (cTnI) are often used in isolation but interpreted interchangeably. Research suggests, however, that post-exercise cTn kinetic might differ with each isoform. In this cross-sectional observational study, we collected blood samples before, immediately after (5 minutes), and at 1-, 3-, 6-, 12-, and 24-hour post-exercise in a mixed cohort of 56 participants after a distance-trial of 60 min continuous swimming (age range from 14 to 22, 57.1% female). Cardiac troponin kinetics were modelled using Bayesian mixed-effects models to estimate time to peak (TTP) and peak concentration (PC) for each isoform, while controlling for participants sex, tanner stage and average relative heart rate during the test. Exercise induced an elevation of cTnT and cTnI in 93% and 75% of the participants, respectively. Cardiac troponin T peaked earlier, at 2.9 h (CI: 2.6 – 3.2 h) post-exercise, whereas cTnI peaked later, at 4.5 h (CI: 4.2 – 4.9 h). Peak concentrations for cTnT and cTnI were 2.5 ng/L, CI: 0 – 11.2 ng/L and 2.16 ng/L, CI: 0 – 22.7 ng/L, respectively. Additionally, we did not observe a systematic effect of sex and maturational status mediating cTn responses.

Intermittent propulsion in largemouth bass, Micropterus salmoides, increases power production at low swimming speeds.

Locomotion dominates animal energy budgets, and selection should favour behaviours that minimize transportation costs. Recent fieldwork has altered our understanding of the preferred modes of locomotion in fishes. For instance, bluegill employ a sustainable intermittent swimming form with 2-3 tail beats alternating with short glides. Volitional swimming studies in the laboratory with bluegill suggest that the propulsive phase reflects a fixed-gear constraint on body-caudal-fin activity. Largemouth bass (Micropterus salmoides) also reportedly display intermittent swimming in the field. We examined swimming by bass in a static tank to quantify the parameters of volitional locomotion, including tailbeat frequency and glide duration, across a range of swimming speeds. We found that tailbeat frequency was not related to speed at low swimming speeds. Instead, speed was a function of glide duration between propulsive events, with glide duration decreasing as speed increased. The propulsive Strouhal number remained within the range that maximizes propulsive efficiency. We used muscle mechanics experiments to simulate power production by muscle operating under intermittent versus steady conditions. Workloop data suggest that intermittent activity allows fish to swim efficiently and avoid the drag-induced greater energetic cost of continuous swimming. The results offer support for a new perspective on fish locomotion: intermittent swimming is crucial to aerobic swimming energetics.

Development and Stiffness Optimization for a Flexible-Tail Robotic Fish

The integral flexible tail has the potential advantage of lifelike undulating motion. However, due to the complex manufacturing process and difficult modification of structural parameters, its application in robotic fish encounters many challenges. Combining rigid structure and flexible material, this letter proposes a passive flexible fish tail, which can achieve continuous movement and high swimming frequency with simple but effective structure. First, with the full consideration of bending deformation of the spring steels, a dynamic model is established. Next, a passive fitting method is particularly applied to imitate the traveling wave model of the carangiform fish. More importantly, a calculation model, which can be used to acquire the theoretical ranges of the stiffness of spring steels, is derived based on the bending model of the cantilever beam subjected to the concentrated force and moment. Finally, the extensive simulation and experiments validate the effectiveness of the proposed methods, and the designed robotic fish can achieve 0.77 m/s (i.e., 1.12 BL/s) at a swimming frequency of 2.5 Hz. The obtained results can provide a valuable sight for improving the swimming performance of the robotic fish.

The effect of 8 weeks of continuous and high intensity interval swimming on chemerin levels in liver and visceral fat tissues and insulin resistance in male rats with metabolic syndrome

هدف: هدف از پژوهش حاضر بررسی تأثیر هشت هفته تمرین شنای تداومی و تناوبی شدید بر مقادیر کمرین بافت چربی احشایی و کبد و مقاومت به انسولین در موش‌های مبتلا به سندروم متابولیک است. روش‌ها: پس از القای موش‌ها به سندروم متابولیک، به‌منظور اجرای برنامه، موش‌ها (32n=) به‌طور تصادفی به چهار گروه (8n=) کنترل استاندارد یا سالم، کنترل سندروم متابولیک، شنای تداومی و شنای تناوبی شدید (مبتلا به سندروم متابولیک) تقسیم شدند. برنامه‌های شنای تداومی و تناوبی شدید به‌ترتیب با 65 درصد و تقریباً معادل 100 درصد اکسیژن مصرفی بیشینه اجرا شد. اندازه‌گیری متغیرهای خونی و بافتی (چربی احشایی و کبد) با روش الایزا و تحلیل آماری با استفاده از آزمون تحلیل واریانس با اندازه‌گیری مکرر انجام گرفت.نتایج: شنای تداومی و تناوبی شدید سبب کاهش معنادار سطح سرمی گلوکز (001/0P=) شد، ولی تغییر معناداری در مقاومت به انسولین (77/0P=) و کمرین بافت کبد (228/0P=) ایجاد نشد. تنها شنای تناوبی شدید سبب کاهش معنادار کمرین بافت چربی احشایی (0001/0P=) و وزن موش‌ها (029/0P=) شد.نتیجه‌گیری: با توجه به نتایج پژوهش حاضر، تمرینات شنای تداومی و تناوبی شدید می‌تواند به‌عنوان رویکردی پیشگیرانه در بهبود مقاومت به انسولین و سندروم متابولیک مورد توجه قرار گیرد، اما اجرای آن به‌صورت تناوبی شدید، اثربخش‌تر خواهد بود. نتیجه‌گیری قطعی به پژوهش‌های بیشتری نیاز دارد.

Evolutionary divergence of locomotion in two related vertebrate species.

Locomotion exists in diverse forms in nature; however, little is known about how closely related species with similar neuronal circuitry can evolve different navigational strategies to explore their environments. Here, we investigate this question by comparing divergent swimming pattern in larval Danionella cerebrum (DC) and zebrafish (ZF). We show that DC displays long continuous swimming events when compared with the short burst-and-glide swimming in ZF. We reveal that mesencephalic locomotion maintenance neurons in the midbrain are sufficient to cause this increased swimming. Moreover, we propose that the availability of dissolved oxygen and timing of swim bladder inflation drive the observed differences in the swim pattern. Our findings uncover the neural substrate underlying the evolutionary divergence of locomotion and its adaptation to their environmental constraints.

Ontogeny and ecological significance of metabolic rates in sea turtle hatchlings

BackgroundSea turtle hatchlings must avoid numerous predators during dispersal from their nesting beaches to foraging grounds. Hatchlings minimise time spent in predator-dense neritic waters by swimming almost continuously for approximately the first 24 h post-emergence, termed the ‘frenzy’. Post-frenzy, hatchling activity gradually declines as they swim in less predator-dense pelagic waters. It is well documented that hatchlings exhibit elevated metabolic rates during the frenzy to power their almost continuous swimming, but studies on post-frenzy MRs are sparse.ResultsWe measured the frenzy and post-frenzy oxygen consumption of hatchlings of five species of sea turtle at different activity levels and ages to compare the ontogeny of mass-specific hatchling metabolic rates. Maximal metabolic rates were always higher than resting metabolic rates, but metabolic rates during routine swimming resembled resting metabolic rates in leatherback turtle hatchlings during the frenzy and post-frenzy, and in loggerhead hatchlings during the post-frenzy. Crawling metabolic rates did not differ among species, but green turtles had the highest metabolic rates during frenzy and post-frenzy swimming.ConclusionsDifferences in metabolic rate reflect the varying dispersal stratagems of each species and have important implications for dispersal ability, yolk consumption and survival. Our results provide the foundations for links between the physiology and ecology of dispersal of sea turtles.

Instability caused swimming of ferromagnetic filaments in pulsed field

Magnetic filaments driven by external magnetic field are an interesting topic of research in-terms of the possible bio-medical applications. In this paper, we investigated the applicability of using ferromagnetic filaments as micro swimmers both experimentally and numerically. It was found that applying a pulse wave field profile with a duty cycle of 30% induced experimentally observable swimming, which is similar to the breast stroke of micro algae. Good agreement with numerical simulations was found. Moreover, for stable continuous swimming, an initial filament shape is required to avoid transition to the structurally preferred non-swimming S-like mode.