Low plasma lactate concentration as a biomarker of an incompetent brain-pull: a risk factor for weight gain in type 2 diabetes patients.

OBJECTIVE: Body weight development is closely regulated by central nervous mechanisms. As has been demonstrated recently, the capability of the brain to actively demand energy from the body (brain-pull) is indispensable for the maintenance of systemic homeostasis. A deficit in this brain-pull may result in compensatory ingestive behavior followed by weight gain in the medium or long term. The aim of this study was to establish a biomarker of such an incompetent brain-pull. Since lactate is an alternative cerebral energy substrate to glucose, we investigated whether low fasting plasma lactate concentrations are associated with weight gain and increased feelings of hunger in patients with type 2 diabetes over a 3-year period. METHODS: In a population based cohort study 134 type 2 diabetes patients were examined at baseline and 3-year follow-up. Plasma lactate concentrations and additional hormones associated with food intake such as e.g. insulin, or leptin, as well as psychological variables like hunger feelings before and after a standardized breakfast were measured. The relation between fasting plasma lactate concentrations and postprandial hunger as well as follow-up weight was analyzed. RESULTS: Low fasting plasma lactate concentrations predicted a higher 3-year follow-up weight (B=-1.268, SE=0.625, p=0.04). Moreover, low fasting plasma lactate concentrations were associated with more pronounced feelings of postprandial hunger (B=-0.406, SE=0.137, p<0.01). CONCLUSIONS: We conclude that low plasma lactate concentrations may represent a biomarker of an incompetent brain-pull, which is associated with weight gain and increased postprandial hunger in patients with type 2 diabetes mellitus. These results are in line with the view that plasma lactate can be used by the brain as an alternative energy substrate and thereby to some extent prevent overeating and obesity.

Large-Area Photo-Mosaics Using Global Alignment and Navigation Data

Seafloor imagery is a rich source of data for the study of biological and geological processes. Among several applications, still images of the ocean floor can be used to build image composites referred to as photo-mosaics. Photo-mosaics provide a wide-area visual representation of the benthos, and enable applications as diverse as geological surveys, mapping and detection of temporal changes in the morphology of biodiversity. We present an approach for creating globally aligned photo-mosaics using 3D position estimates provided by navigation sensors available in deep water surveys. Without image registration, such navigation data does not provide enough accuracy to produce useful composite images. Results from a challenging data set of the Lucky Strike vent field at the Mid Atlantic Ridge are reported

Gut Microbiota Composition in Male Rat Models under Different Nutritional Status and Physical Activity and Its Association with Serum Leptin and Ghrelin Levels.

BACKGROUND Several evidences indicate that gut microbiota is involved in the control of host energy metabolism. OBJECTIVE To evaluate the differences in the composition of gut microbiota in rat models under different nutritional status and physical activity and to identify their associations with serum leptin and ghrelin levels. METHODS IN A CASE CONTROL STUDY, FORTY MALE RATS WERE RANDOMLY ASSIGNED TO ONE OF THESE FOUR EXPERIMENTAL GROUPS: ABA group with food restriction and free access to exercise; control ABA group with food restriction and no access to exercise; exercise group with free access to exercise and feed ad libitum and ad libitum group without access to exercise and feed ad libitum. The fecal bacteria composition was investigated by PCR-denaturing gradient gel electrophoresis and real-time qPCR. RESULTS In restricted eaters, we have found a significant increase in the number of Proteobacteria, Bacteroides, Clostridium, Enterococcus, Prevotella and M. smithii and a significant decrease in the quantities of Actinobacteria, Firmicutes, Bacteroidetes, B. coccoides-E. rectale group, Lactobacillus and Bifidobacterium with respect to unrestricted eaters. Moreover, a significant increase in the number of Lactobacillus, Bifidobacterium and B. coccoides-E. rectale group was observed in exercise group with respect to the rest of groups. We also found a significant positive correlation between the quantity of Bifidobacterium and Lactobacillus and serum leptin levels, and a significant and negative correlation among the number of Clostridium, Bacteroides and Prevotella and serum leptin levels in all experimental groups. Furthermore, serum ghrelin levels were negatively correlated with the quantity of Bifidobacterium, Lactobacillus and B. coccoides-Eubacterium rectale group and positively correlated with the number of Bacteroides and Prevotella. CONCLUSIONS Nutritional status and physical activity alter gut microbiota composition affecting the diversity and similarity. This study highlights the associations between gut microbiota and appetite-regulating hormones that may be important in terms of satiety and host metabolism.

Efectividad de la terapia cognitivo-conductual en la pérdida de peso tras dos años de cirugía bariátrica en pacientes con obesidad mórbida.

To evaluate the effectiveness of Cognitive Behavioral Therapy (CBT) in the success of postoperative weight loss after 2 years of CB. METHODS: A prospective observational study was conducted in consecutive patients with morbid obesity aged between 18 and 59 yrs and enrolled in the bariatric surgery program of the Obesity Surgery Unit of our hospital from June 2007 through June 2010, with two years postoperative follow-up. Participants were divided into two groups according to their participation in Cognitive Behavioral Therapy or not. Over a 3-month period, CBT was applied in 12 2-h sessions. The main dependent variables studied were body weight and height, from which we calculated BMI and percentage of excess weight lost (weight lost x 100)/(initial weight-ideal weight), classifying patients as successful (E ) those with EPP > 50%, and unsuccessful (NE) those with EPP <50%. Participants were also, assessed for general (stress, anxiety, depression and self-esteem) and specific (binge eating and food craving) psychopathology. RESULTS: Of the 35 patients with bariatric surgery, 30 responded postoperative evaluations, 16 underwent CBT before CB and 14 underwent surgery without receiving psycho-nutritional therapy, (76% female) with a mean age of 41 ± 9.5 years. The mean baseline BMI was 42 ± 10 and 45% of patients were classified as super obese (BMI: 56 ± 6). Mean excess weight loss (EPP) was 77%. According to the EPP were classified as "successful" (S) (59%) and "unsuccessful" (U) (41%). Of the patients assigned to S, 94% received CBT (15 individuals of 17 total), compared with only 12% who did not receive (2 individuals of the 17 total) with statistically significant differences (p < 0.05). Also, the S patients appeared to be significantly less anxious and stressed and have higher self-esteem (P < 0.05). Regarding specific psychopathology, the food craving guided by hunger, loss of control over food intake and guilt was lower in patients who achieved > 50% of EPP (p < 0.04, p < 0.001, p < 0.001, respectively). It was also noted that these patients were plans to eat less and ate less for positive reinforcement (p < 0.03 and p < 0.000, respectively) than the patient group NE

The Tertiary structural and thermal evolution of the central Alps - Compressional and extensional structures in an orogenic belt

The Western Alpine Are has been created during the Cretaceous and the Tertiary orogenies. The interference patterns of the Tertiary structures suggest their formation during continental collision of the European and the Adriatic Plates, with an accompanying anticlockwise rotation of the Adriatic indenter. Extensional structures are mainly related to ductile deformation by simple shear. These structures developed at a deep tectonic level, in granitic crustal rocks, at depths in excess of 10 km. In the early Palaeogene period of the Tertiary Orogeny, the main Tertiary nappe emplacement resulted from a NW-thrusting of the Austroalpine, Penninic and Helvetic nappes. Heating of the deep zone of the Upper Cretaceous and Tertiary nappe stack by geothermal heat flow is responsible for the Tertiary regional metamorphism, reaching amphibolite-facies conditions in the Lepontine Gneiss Dome (geothermal gradient 25 degrees C/ km). The Tertiary thrusting occurred mainly during prograde metamorphic conditions with creation of a penetrative NW-SE-oriented stretching lineation, X(1) (finite extension), parallel to the direction of simple shear. Earliest cooling after the culmination of the Tertiary metamorphism, some 38 Ma ago, is recorded by the cooling curves of the Monte Rosa and Mischabel nappes to the west and the Suretta Nappe to the east of the Lepontine Gneiss Dome. The onset of dextral transpression, with a strong extension parallel to the mountain belt, and the oldest S-vergent `'backfolding'' took place some 35 to 30 Ma ago during retrograde amphibolite-facies conditions and before the intrusion of the Oligocene dikes north of the Periadriatic Line. The main updoming of the Lepontine Gneiss Dome started some 32-30 Ma ago with the intrusion of the Bergell tonalites and granodiorites, concomitant with S-vergent backfolding and backthrusting and dextral strike-slip movements along the Tonale and Canavese Lines (Argand's Insubric phase). Subsequently, the center of main updoming migrated slowly to the west, reaching the Simplon region some 20 Ma ago. This was contemporaneous with the westward migration of the Adriatic indenter. Between 20 Ma and the present, the Western Aar Massif-Toce culmination was the center of strong uplift. The youngest S-vergent backfolds, the Glishorn anticline and the Berisal syncline fold the 12 Ma Rb/Sr biotite isochron and are cut by the 11 Ma old Rhone-Simplon Line. The discrete Rhone-Simplon Line represents a late retrograde manifestation in the preexisting ductile Simplon Shear Zone. This fault zone is still active today. The Oligocene-Neogene dextral transpression and extension in the Simplon area were concurrent with thrusting to the northwest of the Helvetic nappes, the Prealpes (35-15 Ma) and with the Jura thin-skinned thrust (11-3 Ma). It was also contemporaneous with thrusting to the south of the Bergamasc (> 35-5 Ma) and Milan thrusts (16-5 Ma).

Oleoylethanolamide enhances β-adrenergic-mediated thermogenesis and white-to-brown adipocyte phenotype in epididymal white adipose tissue in rat.

β-adrenergic receptor activation promotes brown adipose tissue (BAT) β-oxidation and thermogenesis by burning fatty acids during uncoupling respiration. Oleoylethanolamide (OEA) can inhibit feeding and stimulate lipolysis by activating peroxisome proliferator-activating receptor-α (PPARα) in white adipose tissue (WAT). Here we explore whether PPARα activation potentiates the effect of β3-adrenergic stimulation on energy balance mediated by the respective agonists OEA and CL316243. The effect of this pharmacological association on feeding, thermogenesis, β-oxidation, and lipid and cholesterol metabolism in epididymal (e)WAT was monitored. CL316243 (1 mg/kg) and OEA (5 mg/kg) co-administration over 6 days enhanced the reduction of both food intake and body weight gain, increased the energy expenditure and reduced the respiratory quotient (VCO2/VO2). This negative energy balance agreed with decreased fat mass and increased BAT weight and temperature, as well as with lowered plasma levels of triglycerides, cholesterol, nonessential fatty acids (NEFAs), and the adipokines leptin and TNF-α. Regarding eWAT, CL316243 and OEA treatment elevated levels of the thermogenic factors PPARα and UCP1, reduced p38-MAPK phosphorylation, and promoted brown-like features in the white adipocytes: the mitochondrial (Cox4i1, Cox4i2) and BAT (Fgf21, Prdm16) genes were overexpressed in eWAT. The enhancement of the fatty-acid β-oxidation factors Cpt1b and Acox1 in eWAT was accompanied by an upregulation of de novo lipogenesis and reduced expression of the unsaturated-fatty-acid-synthesis enzyme gene, Scd1. We propose that the combination of β-adrenergic and PPARα receptor agonists promotes therapeutic adipocyte remodelling in eWAT, and therefore has a potential clinical utility in the treatment of obesity.

Assessment of melanocytic skin lesions with a high-definition laser Doppler imaging system.

BACKGROUND: Early detection is a major goal in the management of malignant melanoma. Besides clinical assessment many noninvasive technologies such as dermoscopy, digital dermoscopy and in vivo laser scanner microscopy are used as additional methods. Herein we tested a system to assess lesional perfusion as a tool for early melanoma detection.¦METHODS: Laser Doppler flow (FluxExplorer) and mole analyser (MA) score (FotoFinder) were applied to histologically verified melanocytic nevi (33) and malignant melanomas (12).¦RESULTS: Mean perfusion and MA scores were significantly increased in melanoma compared to nevi. However, applying an empirically determined threshold of 16% perfusion increase only 42% of the melanomas fulfilled the criterion of malignancy, whereas with the mole analyzer score 82% of the melanomas fulfilled the criterion of malignancy.¦CONCLUSION: Laser Doppler imaging is a highly sensitive technology to assess skin and skin tumor perfusion in vivo. Although mean perfusion is higher in melanomas compared to nevi the high numbers of false negative results hamper the use of this technology for early melanoma detection.

Structural and metamorphic evolution of the northern Himachal Himalaya, NW India - (Spiti-eastern Lahul-Parvati valley traverse)

The Himalayan orogen is the result of the collision between the Indian and Asian continents that began 55-50 Ma ago, causing intracontinental thrusting and nappe formation. Detailed mapping as well as structural and microfabric analyses on a traverse from the Tethyan Himalaya southwestward through the High Himalayan Crystalline and the Main Central Thrust zone (MCT zone) to the Lesser Himalayan Sequence in the Spiti-eastern Lahul-Parvati valley area reveal eight main phases of deformation, a series of late stage phases and five stages of metamorphic crystallization. This sequence of events is integrated into a reconstruction of the tectonometamorphic evolution of the Himalayan orogen in northern Himachal Pradesh. The oldest phase D-1 is preserved as relies in the High Himalayan Crystalline. Its deformational conditions are poorly known, but the metamorphic evolution is well documented by a prograde metamorphism reaching peak conditions within the upper amphibolite facies. This indicates that D-1 was an important tectonometamorphic event including considerable crustal thickening. The structural, metamorphic and sedimentary record suggest that D-1 most probably represents an early stage of continental collision. The first event clearly attributed to the collision between India and Asia is documented by two converging nappe systems, the NE-verging Shikar Beh Nappe and the SW-verging north Himalayan nappes. The D-2 Shikar Beh Nappe is characterized by isoclinal folding and top-to-the NE shearing, representing the main deformation in the High Himalayan Crystalline. D-2 also caused the main metamorphism in the High Himalayan Crystalline that was of a Barrovian-type, reaching upper amphibolite facies peak conditions. The Shikar Beh Nappe is interpreted to have formed within the Indian crust SW of the subduction zone. Simultaneously with NE-directed nappe formation, incipient subduction of India below Asia caused stacking of the SW-verging north Himalayan Nappes, that were thrust from the northern edge of the subducted continent toward the front of the Shikar Beh Nappe. As a result, the SW-verging folds of the D-3 Main Fold Zone formed in the Tethyan Himalaya below the front of the north Himalayan nappes. D-3 represents the main deformation in the Tethyan Himalaya, associated with a greenschist facies metamorphism. Folding within the Main Fold Zone subsequently propagated toward SW into the High Himalayan Crystalline, where it overprinted the preexisting D-2 structures. After subduction at the base of the north Himalayan nappes, the subduction zone stepped to the base of the High Himalayan Crystalline, where D-3 folds were crosscut by SW-directed D-4 thrusting. During D-4, the Crystalline Nappe, comprising the Main Fold Zone and relies of the Shikar Beh Nappe was thrust toward SW over the Lesser Himalayan Sequence along the 4 to 5 kms thick Main Central Thrust zone. Thrusting was related to a retrograde greenschist facies overprint at the base of the Crystalline Nappe and to pro-grade greenschist facies conditions in the Lesser Himalayan Sequence. Simultaneously with thrusting at the base of the Crystalline Nappe, higher crustal levels were affected by NE-directed D-5 normal extensional shearing and by dextral strike-slip motion, indicating that the high-grade metamorphic Crystalline Nappe was extruded between the low-grade metamorphic Lesser Himalayan Sequence at the base and the north Himalayan nappes at the top. The upper boundary of the Crystalline Nappe is not clearly delimited and passes gradually into the low-grade rocks at the front of the north Himalayan nappes. Extrusion of the Crystalline Nappe was followed by the phase D-6, characterized by large-scale, upright to steeply inclined, NE-verging folds and by another series of normal and extensional structures D-7+D-8 that may be related to ongoing extrusion of the Crystalline Nappe. The late stage evolution is represented by the phases D-A and D-B that indicate shortening parallel to the axis of the mountain chain and by D-C that is interpreted to account for the formation of large-scale domes with NNW-SSE-trending axes, an example of which is exposed in the Larji-Kullu-Rampur tectonic window.

Detailed 3D seismic imaging of a fault zone beneath Lake Geneva, Switzerland

An efficient high-resolution (HR) three-dimensional (3D) seismic reflection system for small-scale targets in lacustrine settings was developed. In Lake Geneva, near the city of Lausanne, Switzerland, the offshore extension of a complex fault zone well mapped on land was chosen for testing our system. A preliminary two-dimensional seismic survey indicated structures that include a thin (<40 m) layer of subhorizontal Quaternary sediments that unconformably overlie south-east-dipping Tertiary Molasse beds and a major fault zone (Paudeze Fault Zone) that separates Plateau and Subalpine Molasse (SM) units. A 3D survey was conducted over this test site using a newly developed three-streamer system. It provided high-quality data with a penetration to depths of 300 m below the water bottom of non-aliased signal for dips up to 30degrees and with a maximum vertical resolution of 1.1 m. The data were subjected to a conventional 3D processing sequence that included post-stack time migration. Tests with 3D pre-stack depth migration showed that such techniques can be applied to HR seismic surveys. Delineation of several horizons and fault surfaces reveals the potential for small-scale geologic and tectonic interpretation in three dimensions. Five major seismic facies and their detailed 3D geometries can be distinguished. Three fault surfaces and the top of a molasse surface were mapped in 3D. Analysis of the geometry of these surfaces and their relative orientation suggests that pre-existing structures within the Plateau Molasse (PM) unit influenced later faulting between the Plateau and SM. In particular, a change in strike of the PM bed dip may indicate a fold formed by a regional stress regime, the orientation of which was different from the one responsible for the creation of the Paudeze Fault Zone. This structure might have later influenced the local stress regime and caused the curved shape of the Paudeze Fault in our surveyed area.

Linking temperature estimates and microstructures in deformed polymineralic mantle rocks

To constrain deformation temperatures of mantle shear zones, we studied a strike-slip shear zone (Hilti massif, Semail ophiolite, Oman) and focused on the interaction between microstructural mechanisms and chemical equilibration processes. Quantitative microfabric analysis on harzburgites with different deformation intensity (porphyroclastic tectonite, mylonite, and ultramylonite) was combined with orthopyroxene geothermometry. The average grain size of all phases decreases with decreasing shear zone thickness. Dynamic recrystallization of porphyroclasts in combination with dissolution-precipitation and nucleation result in small-sized, chemically equilibrated pyroxenes. The composition of orthopyroxene was used to calculate deformation temperatures. In the case of the porphyroclastic tectonites, the chemical composition of orthopyroxene has been reset by diffusion yielding temperature estimates of 880-900 degrees C. The mylonites were deformed by dislocation creep of olivine and show a broad range of calculated temperatures, which result from a combination of grain size reduction and inheritance of equilibrium compositions from earlier high-temperature events and diffusion. In mylonites, diffusion profiles combined with geothermometry and grain size analysis indicate a mylonitic deformation temperature of 800-900 degrees C possibly followed by diffusion. In ultramylonites, the smallest grains (<30 mu m) reveal equilibration at temperatures of similar to 700 degrees C during the last stages of ductile deformation, which was dominated by diffusion creep of olivine. Our results provide a crucial link between temperature and evolution of microstructures from dislocation creep to diffusion creep in mantle shear zones.

Proximal tibia volumetric bone mineral density is correlated to the magnitude of local acceleration in male long distance runners.

Introduction: The beneficial effect of physical exercise on bone mineral density (BMD) is at least partly explained by the forces exerted directly on the bones. Male runners present generally higher BMD than sedentary individuals. We postulated that the proximal tibia BMD is related to the running distance as well as to the magnitude of the shocks (while running) in male runners. Methods: A prospective study (three yearly measurements) included 81 healthy male subjects: 16 sedentary lean subjects and three groups of runners (5-30 km/week, n=19; 30-50 km/week, n=29; 50-100 km/week, n=17). Several measurements were performed at the proximal tibia level: volumetric BMD (vBMD), cortical index (CI) i.e. an index of cortical bone thickness and peak accelerations (an index of shocks during heel strike) while running (measured by a 3-D accelerometer). A general linear model assessed the prediction of vBMD or CI by a) simple effects (running distance, peak accelerations, time) and b) interactions (for instance if vBMD prediction by peak acceleration depends on running distance). Results: CI and vBMD a) increase with running distance to reach a plateau over 30 km/wk, b) are positively associated with peak accelerations over 30 km/week. Discussion: Running may be associated with high peak accelerations in order to have beneficial effects on BMD. More important strains are needed to be associated with the same increase in BMD during running sessions of short duration than those of long duration. Conclusion: CI and vBMD are associated with the magnitude of the shocks during heel strike in runners. Key words: Bone mineral density, strains, physical exercise, running distance.

Big brother is watching you: eavesdropping to resolve family conflicts

Adult animals can eavesdrop on behavioral interactions between potential opponents to assess their competitive ability and motivation to contest resources without interacting directly with them. Surprisingly, eavesdropping is not yet considered as an important factor used to resolve conflicts between family members. In this study, we show that nestling barn owls (Tyto alba) competing for food eavesdrop on nestmates' vocal interactions to assess the dominance status and food needs of opponents. During a first training playback session, we broadcasted to singleton bystander nestlings a simulated vocal interaction between 2 prerecorded individuals, 1 relatively old (i.e., senior) and 1 younger nestling (i.e., junior). One playback individual, the "responder," called systematically just after the "initiator" playback individual, hence displaying a higher hunger level. To test whether nestlings have eavesdropped on this interaction, we broadcasted the same prerecorded individuals separately in a subsequent playback test session. Nestlings vocalized more rapidly after former initiators' than responders' calls and they produced more calls when the broadcasted individual was formerly a junior initiator. They chiefly challenged vocally juniors and initiators against whom the likelihood of winning a vocal contest is higher. Owlets, therefore, identified the age hierarchy between 2 competitors based on their vocalizations. They also memorized the dynamics of competitors' previous vocal interactions, and used this information to optimally adjust signaling level once interacting with only 1 of the competitor. We conclude that siblings eavesdrop on one another to resolve conflicts over parental resources.

High-resolution seismic images of potentially seismogenic structures beneath the northwest Canterbury Plains, New Zealand

The transpressional boundary between the Australian and Pacific plates in the central South Island of New Zealand comprises the Alpine Fault and a broad region of distributed strain concentrated in the Southern Alps but encompassing regions further to the east, including the northwest Canterbury Plains. Low to moderate levels of seismicity (e. g., 2 > M 5 events since 1974 and 2 > M 4.0 in 2009) and Holocene sediments offset or disrupted along rare exposed active fault segments are evidence for ongoing tectonism in the northwest plains, the surface topography of which is remarkably flat and even. Because the geology underlying the late Quaternary alluvial fan deposits that carpet most of the plains is not established, the detailed tectonic evolution of this region and the potential for larger earthquakes is only poorly understood. To address these issues, we have processed and interpreted high-resolution (2.5 m subsurface sampling interval) seismic data acquired along lines strategically located relative to extensive rock exposures to the north, west, and southwest and rare exposures to the east. Geological information provided by these rock exposures offer important constraints on the interpretation of the seismic data. The processed seismic reflection sections image a variably thick layer of generally undisturbed younger (i.e., < 24 ka) Quaternary alluvial sediments unconformably overlying an older (> 59 ka) Quaternary sedimentary sequence that shows evidence of moderate faulting and folding during and subsequent to deposition. These Quaternary units are in unconformable contact with Late Cretaceous-Tertiary interbedded sedimentary and volcanic rocks that are highly faulted, folded, and tilted. The lowest imaged unit is largely reflection-free Permian Triassic basement rocks. Quaternary-age deformation has affected all the rocks underlying the younger alluvial sediments, and there is evidence for ongoing deformation. Eight primary and numerous secondary faults as well as a major anticlinal fold are revealed on the seismic sections. Folded sedimentary and volcanic units are observed in the hanging walls and footwalls of most faults. Five of the primary faults represent plausible extensions of mapped faults, three of which are active. The major anticlinal fold is the probable continuation of known active structure. A magnitude 7.1 earthquake occurred on 4 September 2010 near the southeastern edge of our study area. This predominantly right-lateral strike-slip event and numerous aftershocks (ten with magnitudes >= 5 within one week of the main event) highlight the primary message of our paper: that the generally flat and topographically featureless Canterbury Plains is underlain by a network of active faults that have the potential to generate significant earthquakes.

Coordination pattern variability provides functional adaptations to constraints in swimming performance.

In a biophysical approach to the study of swimming performance (blending biomechanics and bioenergetics), inter-limb coordination is typically considered and analysed to improve propulsion and propelling efficiency. In this approach, 'opposition' or 'continuous' patterns of inter-limb coordination, where continuity between propulsive actions occurs, are promoted in the acquisition of expertise. Indeed a 'continuous' pattern theoretically minimizes intra-cyclic speed variations of the centre of mass. Consequently, it may also minimize the energy cost of locomotion. However, in skilled swimming performance there is a need to strike a delicate balance between inter-limb coordination pattern stability and variability, suggesting the absence of an 'ideal' pattern of coordination toward which all swimmers must converge or seek to imitate. Instead, an ecological dynamics framework advocates that there is an intertwined relationship between the specific intentions, perceptions and actions of individual swimmers, which constrains this relationship between coordination pattern stability and variability. This perspective explains how behaviours emerge from a set of interacting constraints, which each swimmer has to satisfy in order to achieve specific task performance goals and produce particular task outcomes. This overview updates understanding on inter-limb coordination in swimming to analyse the relationship between coordination variability and stability in relation to interacting constraints (related to task, environment and organism) that swimmers may encounter during training and performance.