Reliability of Peak Cardiorespiratory Responses During Aquatic Treadmill Exercise

Twenty-four college-age participants took part in 2 protocols on an aquatic treadmill (ATM) submerged to the xiphoid process. ATM speed was increased to 212.2 + 19.2 m/min, and water-jet resistance was increased 10% every minute thereafter. Rest between sessions was at least 6 days. Oxygen consumption (VO2), heart rate (HR), minute ventilation (VE), tidal volume (VT), breathing frequency (f), and respiratory exchange ratio (RER) were measured continuously. Rating of Perceived Exertion (RPE) was recorded immediately after each test, and blood lactate (LA) was measured 3 min after. There were no significant differences for Trial 1 vs. Trial 2 for any variable. ICCs were very strong (r = .90-.99) and coefficients of variants (CVs) were low (1.3-4.7%) for VO2peak, HR, VE, VT; ICC’s were moderate (r = .73-.76) and CVs were greater (2.5-9.3%) was greater for f, RER and LA. The ATM VO2peak protocol used in this study produces consistent, reproducible VO2peak values

Metabolic-Cost Comparison Between Submaximal Land and Aquatic Treadmill Exercise

Purpose: To evaluate the metabolic cost of varying aquatic treadmill (ATM) exercise speed and water-jet resistance and compare with land treadmill (TM) conditions at similar running speeds. Methods: 15 participants (7 men, 8 women, age 22 + 4 years, height 173 + 8 cm, weight 66.9 + 9 kg) submerged to the xiphoid process completed nine 5-min submaximal ATM trials at 174-, 201-, and 228-m/min treadmill speeds with water-jet resistances set at 0%, 50%, and 75% of capacity. Oxygen consumption (VO2), expired ventilation (VE[BTPS]), tidal volume (VT), breath frequency (f), heart rate (HR), oxygen (O2), pulse, and ratings of perceived exertion (RPE) were recorded during each trial. The corresponding TM speeds that yielded VO2 costs similar to ATM conditions were determined. Repeated measures ANOVA and paired t tests were employed to determine significance (p \u3c .05). Results: Increasing running speed and water-jet resistance both significantly increased VO2, HR, VE, (VE[BTPS]), pulse, and RPE. Women were lower (p \u3c .05) than men in VO2, (VE[BTPS]), O2, pulse, and VT, and higher in HR and f in all ATM trials. Comparable (p \u3c .05) metabolic costs (VO2) were observed when TM speeds were similar to ATM speeds without jet resistance. The addition of jet resistance increased (p \u3c .01) the land TM required to elicit a similar metabolic costs by 27.8 and 54.6 m/min, respectively. Conclusions: These results suggest ATM yields similar metabolic costs to land TM in running speeds of 174-228 m/min

The Effect of Water Depth on Energy Expenditure and Perception of Effort in Female Subjects While Walking

The purpose of this study was to compare energy expenditure (EE), heart rate, and perceived effort during walking in water at several depths versus land in female participants. Eighteen females walked on three separate days on a land treadmill (Land) and in a water treadmill (ATM) at 30° C at 6 speeds. Water depth was at the xiphoid (xip), 10 cm below (-10 cm), and 10 cm above xip (+10 cm). Heart rate (HR), oxygen consumption (VO2) and carbon dioxide production (VCO2) were recorded. RPE overall (RPE-O) and RPE legs (RPE-L) were solicited following each bout. Regardless of walking speed, EE and HR were influenced by water depth, with -10 cm significantly greater than xip, +10 cm and Land, and xip significantly greater than +10 cm and Land (all p \u3c 0.001). Land EE and HR were similar to +10 cm. RPE-O was significantly higher for -10 cm vs. xip, +10 cm, and Land, while xip was greater than Land. RPE-L was greater for -10 cm vs. xip, +10 cm and Land, while xip was greater than +10 cm & Land. Our results showed that small changes in water depth influences exercise EE, HR and RPE. These differences are attributed to a changing relationship between drag resistances and buoyancy in water

A Review of Biophysical Differences between Aquatic and Land-Based Exercise

Four of the most popular modes of aquatic exercise are deep-water (DW) exercise, shallow water (SW) exercise, water calisthenics (WC), and underwater treadmill (UT) exercise. The mechanical requirements of each aquatic exercise mode may elicit different physiological and biomechanical responses. The purpose of this descriptive literature review was to evaluate some biophysical differences between aquatic and land-based exercises. The biophysical variables included oxygen consumption (VO2), heart rate (HR), rating of perceived exertion (RPE), stride length, stride frequency, pain, and measures of functional gain. Based on the studies reviewed, when compared to similar land-based exercises, VO2 and HR maximum values were lower during DW and SW exercise, but, depending on water depth and exercise performed, may be greater during WC and UT exercise. RPE during DW exercise was generally similar to land exercise during max effort. Stride frequency tended to be lower for all four aquatic exercises, relative to on-land counterparts. Pain levels tended to be similar between WC and land exercise, yet may decrease after UT exercise

Vision Analysis of Pack Ice for Potential Use in a Hazard Warning and Avoidance System

Ships travelling through pack ice are exposed to collisions that can result in structural damage to the hull. The GEM project at Memorial University has developed ice-ship interaction simulation software that allows study of the impact forces applied on a ship when it maneuvers through pack ice [1]. Such capability is useful in order to predict the collisions that would potentially affect the structural integrity and operational performance of ships and floating offshore structures. GEM is capable of simulating transit through complex pack ice formations at a rate much faster than real time. If hyper-real time simulation were available in a real operational setting, with actual ice, it would permit a variety of benefits, including general operational planning. If the near field ice information were sufficiently accurate, GEM could also be used in a “feed forward” near-field hazard warning and avoidance system (HWAS)

Winners and losers over 35 years of dragonfly and damselfly distributional change in Germany

Aim: Recent studies suggest insect declines in parts of Europe; however, the generality of these trends across different taxa and regions remains unclear. Standardized data are not available to assess large-scale, long-term changes for most insect groups but opportunistic citizen science data are widespread for some. Here, we took advantage of citizen science data to investigate distributional changes of Odonata. Location: Germany. Methods: We compiled over 1 million occurrence records from different regional databases. We used occupancy-detection models to account for imperfect detection and estimate annual distributions for each species during 1980–2016 within 5 × 5 km quadrants. We also compiled data on species attributes that were hypothesized to affect species’ sensitivity to different drivers and related them to the changes in species’ distributions. We further developed a novel approach to cluster groups of species with similar patterns of distributional change to represent multispecies indicators. Results: More species increased (45%) than decreased (29%) or remained stable (26%) in their distribution (i.e. number of occupied quadrants). Species showing increases were generally warm-adapted species and/or running water species, while species showing decreases were cold-adapted species using standing water habitats such as bogs. Time series clustering defined five main patterns of change—each associated with a specific combination of species attributes, and confirming the key roles of species’ temperature and habitat preferences. Overall, our analysis predicted that mean quadrant-level species richness has increased over most of the time period. Main conclusions: Trends in Odonata provide mixed news—improved water quality, coupled with positive impacts of climate change, could explain the positive trends of many species. At the same time, declining species point to conservation challenges associated with habitat loss and degradation. Our study demonstrates the great value of citizen science and the work of natural history societies for assessing large-scale distributional change