Conditions Of Water Movement Research Articles

Compensatory Muscle Activation During Unstable Overhead Squat Using a Water-filled Training Tube.

Glass, SC, and Albert, RW. Compensatory muscle activation during unstable overhead squat using a water-filled training tube. J Strength Cond Res 32(5): 1230-1237, 2018-The purpose of this study was to assess compensatory muscle activation of core and support muscle during an overhead squat using a water-filled training tube. Eleven experienced weightlifting (age = 20.10 ± 0.99, mass 89.17 ± 6.88 kg) men completed 3, 30-second trials of an overhead squat using an 11.4 kg tube that was partially filled with water. A central valve allowed 3 conditions of water movement: 50% open, 100% open, and a stable(S), closed valve condition. Subjects completed 8-10 repetitions within each condition. Electromyographic (EMG) electrodes were placed over the belly of the vastus lateralis, deltoid, rectus abdominus, and paraspinal muscles and recorded during concentric and eccentric (ECC) phases. Integrated EMG were computed and converted to percent maximal voluntary contraction (%MVC). Compensatory activation was assessed using the natural log of the coefficient of variation of %MVC across repetitions. A 1-way repeated-measures analysis of variance across (phase, condition) was used. Significant compensatory muscle activation was seen in the deltoid muscle during ECC (100% open = 3.60 ± 0.50 > stable LogCV = 3.06 ± 0.45). In addition, paraspinal muscle activity was also more variable during the ECC phase (50% open LogCv = 3.28 ± 0.26 > stable = 2.77 ± 0.67). We conclude that the water-filled training tube induces compensatory muscle activation in the deltoid and paraspinal muscles during the ECC phase of the overhead squat.

Core Muscle Activation During Unstable Overhead Squat Using a Water-Filled Training Tube

PURPOSE:Stability and balance are essential components for functional movement. While these components are often developed by exercising on unstable surfaces, another alternative is to use an unstable implement. The purpose of this study was to use a novel water-filled implement (“slosh tube”) to assess the degree of muscle instability created during an overhead squat. METHODS: Eight men (age= 20.1 ± 1.0y, ht=179.8 ± 4.8cm, mass= 89.2 ± 6.9kg) completed three 30s trials of an overhead squat using an 11.4 kg tube that was partially filled with water. A central valve allowed three conditions of water movement: 50% open, 100% open, and a stable(S), closed valve setting. Subjects completed 8-10 repetitions within each condition using a counter-balanced design. Muscle activation was assessed on the right side, with passive EMG electrodes placed over the belly of the vastus lateralis (VLAT), deltoid, rectus abdominus (AB), and paraspinal muscles. Integrated EMG was measured for each repetition and converted to a %MVC for each muscle. Instability was determined using the natural log of the coefficient of variation across repetitions. A two way repeated measures ANOVA across (contraction, condition) was used to examine concentric and eccentric contractions in each muscle. %MVC was also assessed. RESULTS:No significant instability was seen in any muscles for both CON and ECC. LnCV ranged from 3.0-3.5. Percent MVC activated was significantly greater for the Paraspinal muscle (CON= 53.6 ± 7.4, ECC = 45.1± 9.7%) and VLAT (CON= 332.3 ± 147.5, ECC= 288.8 ± 114.5) but not for the AB (CON= 10.6 ± 5.1, ECC= 9.2 ± 4.6) or the Deltoid ( CON= 41.3 ± 19.4, ECC = 39.7 ± 17.7) CONCLUSIONS: We conclude that the overhead squat using an unstable, water-filled tube maintains deltoid and abdominal muscle activation throughout the squat, but does not induce activation instability across the four muscles studied.

Core Muscle Activation During Unstable Leg Extension Using a Water-Filled Training Tube

Creating muscle instability may be an effective means of training for stability. Instability may be achieved using an unstable surface or load. PURPOSE: The purpose of this study was to assess the degree of muscle instability created during a seated leg extension using a novel unstable load (“slosh tube”) under three different conditions. METHODS: Eight men (age= 19.9± 1.6y, ht=178.8 ± 8.9cm, mass= 103.3 ± 48.5kg, Leg Ext 1RM= 136.5 ± 15.9kg ) and eight women (age= 20.1 ± 1.1y, ht=164.9 ± 9.8cm, mass= 62.9 ± 12.2kg, Leg Ext 1RM= 91.5 ± 15.5kg ) completed three, 30s trials of leg extension using an 11.4 kg tube partially filled with water. A central valve allowed three conditions of water movement: 50% open, 100% open, and a stable, balanced valve setting. The valve settings allowed for different water flow dynamics, creating movement during the lift. Subjects completed 8-10 repetitions (20 reps/min) within each condition using a counter-balanced design. Muscle activation was assessed on the right side, with bipolar surface electrodes placed over the vastus lateralis, vastus medialis, rectus abdominus and paraspinal muscles. Integrated EMG was measured (1,000Hz/s) for each repetition and converted to a %MVC for each muscle. Instability was determined using the coefficient of variation across repetitions. A two way repeated measures ANOVA (gender, condition, gender x condition) with post hoc t-tests was used to examine concentric contractions only. RESULTS: Percent MVC activated for the vastus lateralis was significantly greater in women (81.8 ±52.7%) compared to men (48.0 ±27.8%) across all conditions. No differences in % MVC were seen for vastus medialis, rectus abdominus, and paraspinal muscles. There were no differences in instability for any muscle or condition, however abdominal instability was trending toward differences between men( CV= 24.8 ±15.9) and women (CV= 30.5 ± 28.3 p= .06). CONCLUSIONS: We conclude that utilizing an 11.4kg unstable device during seated leg extension does not result in significant instability, however it does result in greater vastus lateralis activation in women compared to men. A heavier load may be required to create the desired unstable conditions for core muscle activation.

Core Muscle Activation During Unstable Bicep Curl Using a Water-Filled Training Tube

Stability and balance are essential components for functional movement. These components may developed by training with unstable surfaces, or unstable loads. PURPOSE: The purpose of this study was to use a novel unstable implement (“slosh tube”) and assess the degree of muscle instability created during a bicep curl. METHODS: Ten men (age= 21± 1.6y, ht=180.0 ± 3.3cm, mass= 87.4 ± 15.0kg) and ten women (age= 19.6± 1.3y, ht=161.4 ± 12.0cm, mass= 61.2 ± 7.4kg) completed three, 30s trials of a bicep curl using an 11.4 kg tube partially filled with water. A central valve allowed three conditions of water movement: 50% open, 100% open, and a balanced, closed valve setting. Subjects completed 8-10 repetitions within each condition (1.5s per rep) using a counter-balanced design. Muscle activation was assessed on the right side, using bipolar surface electrodes placed over the belly of the bicep, deltoid, rectus abdominus and paraspinal muscles. Integrated EMG was measured for each repetition and converted to a %MVC for each muscle. Instability was determined using the coefficient of variation across repetitions. A two way repeated measures ANOVA (gender, condition, gender x condition) with post hoc t-tests was used to examine concentric contractions only. RESULTS: Significant instability was seen in the paraspinal muscles for both genders at the 50% (CV= 26.5 ± 14.5) and 100% (CV= 27.1 ± 9.9) condition compared to stable (CV= 15.0 ± 9.1). Across all subjects the deltoid showed greatest instability at the 100% open setting (CV= 38.5 ± 23.2) compared to stable (CV= 21.0 ± 7.5). For the bicep, men showed greater overall instability (CV= 30.9 ± 17.0) compared to women (CV= 22.9 ± 8.4). There were no differences in abdominal activation in any condition. Percent MVC activated was significantly greater for women for the bicep (50= 97.7 ± 57.6, 100= 88.1 ± 55.6, stable= 87.0 ± 50.1) and paraspinal (50= 36.7 ± 22.3, 100= 47.5 ± 29.0, stable= 38.6 ± 23.9) compared to men (bicep 50= 39.5 ± 17.0, 100= 38.3 ± 18.3, stable= 31.8 ± 11.1) (paraspinal 50= 15.1 ± 10.0, 100= 16.2 ± 8.8, stable= 14.3 ± 9.6). No differences were seen for deltoid or abdominal. CONCLUSIONS: We conclude that a bicep curl using an unstable implement utilizing water inertia causes increased paraspinal and deltoid instability in men and women, with additional instability in the bicep for men.

Ultrastructure and dispersal potential of sponge larvae: tufted versus evenly ciliated parenchymellae

AbstractIn this work we analyse the ultrastructure and behaviour of two representative types of parenchymella sponge larvae: the evenly ciliated larva of Scopalina lophyropoda, and the tufted larva of Cacospongia mollior. We sought to find correlates of the dispersal abilities and distribution patterns of these species. Laboratory experiments were performed under two different conditions of water movement (still water and a slight oscillatory movement), and at different times of the larval life‐span. Larvae of S. lophyropoda were motionless most of the time, maintaining a vertical posture and rotating on their main axis, and they did not respond to directional light. Larvae of C. mollior were active swimmers that responded negatively to light stimuli. In both cases, movement decreased as the larval age increased. Ultrastructurally, C. mollior larvae were more compact, with more reserves and abundant collagen bundles. Desmosome‐like structures were seen connecting the apical parts of the ciliated surface in both species. Two different types of putative light‐sensitive structures were found. Both structural and behavioural characteristics favour a greater dispersal capability for C. mollior and a philopatric dispersal mode for S. lophyropoda. These predictions are in agreement with the observed ecological distribution of the species.

Investigator Group Expedition 2006: Flexible Foraging Ecologyofa Temperate Herbivore, The Herring Cale, Olisthops Cyanomelas, in South Australia

The odacine fish, herring cale (HC), Olisthops cyanomelas, is a facultative browser, feeding mainly on the secondary laminae of Ecklonia radiata, and the apical receptacles of the fucoids, Cystophora spp. and Sargassum spp. Diet, daily feeding rates and time budgets of HC were examined at two South Australian sites >1000 km apart and in different water movement conditions, with additional dietary data from an exposed site. The diet and feeding behaviour were habitat-dependent. At one partly-sheltered site with abundant Ecklonia, HC was most active immediately after dawn and toward dusk, whereas at the other more sheltered site, dominated by fucoid algae, it was inactive at dawn increasing to a moderate level of activity in mid-morning, and peaking toward sunset. Feeding bite rates were variable and mean rates ranged from 8 – 14.5 min−1 according to site. HC characteristically engaged in intermittent foraging bouts, interspersed with periods of inactivity, which averaged ~ 55% of daylight hours. Interactions with other species were few. Analysis showed no significant differences between small and large HC in bite rates, but significant between-site differences in bite rates, and in the proportion of time spent foraging and swimming. In this study HC did not destroy patches of the kelp, Ecklonia, as it does in eastern Australia, even when the kelp comprises the main diet, because it fed only on the distal parts of the kelp’s secondary laminae and meristem.

Water content variations and respective ecosystems of sandy land in China

Soil water conservation is essential to the sustainability of sandy farming. In this paper, long-term observation of soil water, dry soil thickness and soil chemical changes are evaluated at eight locations in sandy soil. This paper subdivides the sandy lands and deserts of China into three climate zones: arid (hyperarid and extremely arid), semiarid, and humid (subhumid and subtropical humid), with respect to the bioclimatic zone, aridity, soil water content, and soil chemical characteristics. The water movement conditions, and chemical variations in each zone are analyzed. The paper also estimates the spatial and temporal correlation function of arid soil thickness and soil moisture. Sandy soils organic matter content, CaCO3 content, soluble salts content are investigated. Afforestation and selection of tree species in different sandy areas are suggested to regulate sandy land soil moisture. Sandy land in China can be divided into the four sand stabilization regions according to the shifting sand conditions and the techniques advanced: regions I, II, III, and IV. These results have important implications for remote sensing of soil moisture and soil organic carbon, and soil moisture parameterization in climate models.

Biogenic amines and pheromones as feed attractants for the freshwater prawn Macrobrachium rosenbergii

The use of attractants in formulated feeds has become paramount to economic success owing to the need to optimize feed conversion rates by maximizing consumption and reducing feed waste so as to lower production costs. Taking into account the importance of attractants, a series of experiments designed to evaluate the potential of natural molecules was carried out with the freshwater prawn, Macrobrachium rosenbergii (De Man, 1879). Two biogenic amines (putrescine and cadaverine) and two sexual pheromones (crab urine and freshwater prawn green gland extracts) were compared with reference products proven to be major attractants, such as squid extracts and a commercial product. These were incorporated in a basal diet designed to be non-attractive. Results were obtained by three different approaches. First, a laboratory bioassay was conducted to evaluate the time that lapsed as an animal presented the different alimentary stages (perception, orientation, movement, arrival and ingestion). A second approach was developed in a commercial farm, to test the performance of the attractants in the presence of other stimuli and in conditions of water movement that may cause rapid dilution. The test consisted of placing a quantity of feed on a tray, which was submerged in a cage (1 m3) in which 10 animals (five males and five females) of 20 g mean weight were placed. The tray was lifted at different times (10, 20, 40 and 80 rain) and the number of pellets left was counted. Three replicates were performed for each treatment. A third approach consisted of incorporating an antibody in the feed. Following a methodology similar to the above-mentioned, hepatopancreas and mouth parts of the prawns were collected at different times. Later, immunodiffusion tests were executed to assess the actual ingestion of the feed. The results obtained from the different approaches indicated that cadaverine included at 0.2% was the best attractant. On the other hand, the crab urine and freshwater prawn green gland extracts exhibited good results only with males, so their utilization could be recommended for monosexual cultures.

Orientierung der GorgonarieEunicella cavolinii zur Wasserbewegung

1. In situ studies were performed on orientation of the planes of branching in colonies of the gorgonianEunicella cavolinii growing in locations of different topography and water movement. Employing frequency analysis, orientation patterns were revealed which demonstrated the influence of water movement on these orientations. 2. The importance of substratum morphology was demonstrated by staining individual water bodies with fluorescein sodium. 3. A typical modification in growth pattern ofE. cavolinii is characterized, indicating zones of strong whirls and turbulence: the second critical depth (Riedl 1964, 1971). 4. The second critical depth can be defined by projected circumscription of fan-top views plotted against depth as well as the flowing zone and oscillation zone. In zones of stable water movement directions, the projected area of fan-top views show only slight variations, expressed by the standard deviations. 5. In situ experiments demonstrate clearly the effect of water movement on growth pattern and fan orientation inE. cavolinii. Colonies of various sizes were turned from their natural position perpendicular to the direction of water movement until the fan was parallel to this direction. During structural re-adjustment, the following responses could be noted: (a) Inhibition of growth for the first 5 months; (b) new growth perpendicular to the original fan plane; (c) compensation in branches whose tips grew in new directions; (d) occasional loss of the two-dimensional shape under the new conditions of water movement. 6. Growth rate was compared in experimental and undisturbed colonies. Growth rate was in most cases lower in experimental than in undisturbed colonies. 7. The mechanisms of reorientation ofE. cavolinii under the new conditions of water movement are discussed in the light of comparable responses shown by other organisms.