Abstract:Pattern recognition of electromyography (EMG) signals can potentially improve the performance of myoelectric control for upper limb prostheses with respect to current clinical approaches based on direct control. However, the choice of features for classification is challenging and impacts long-term performance. Here, we propose the use of EMG raw signals as direct inputs to deep networks with intrinsic feature extraction capabilities recorded over multiple days. Seven able-bodied subjects performed six active motions (plus rest), and EMG signals were recorded for 15 consecutive days with two sessions per day using the MYO armband (MYB, a wearable EMG sensor). The classification was performed by a convolutional neural network (CNN) with raw bipolar EMG samples as the inputs, and the performance was compared with linear discriminant analysis (LDA) and stacked sparse autoencoders with features (SSAE-f) and raw samples (SSAE-r) as inputs. CNN outperformed (lower classification error) both LDA and SSAE-r in the within-session, between sessions on same day, between the pair of days, and leave-out one-day evaluation (p
Human adaptation to extreme environments has been explored for over a century to understand human psychology, integrated physiology, comparative pathologies, and exploratory potential. It has been demonstrated that these environments can provide multiple external stimuli and stressors, which are sufficient to disrupt internal homeostasis and induce adaptation processes. Multiday hyperbaric and/or saturated (HBS) environments represent the most understudied of environmental extremes due to inherent experimental, analytical, technical, temporal, and safety limitations. National Aeronautic Space Agency (NASA) Extreme Environment Mission Operation (NEEMO) is a space-flight analog mission conducted within Florida International University's Aquarius Undersea Research Laboratory (AURL), the only existing operational and habitable undersea saturated environment. To investigate human objective and subjective adaptations to multiday HBS, we evaluated aquanauts living at saturation for 9-10 days via NASA NEEMO 22 and 23, across psychologic, cardiac, respiratory, autonomic, thermic, hemodynamic, sleep, and body composition parameters. We found that aquanauts exposed to saturation over 9-10 days experienced intrapersonal physical and mental burden, sustained good mood and work satisfaction, decreased heart and respiratory rates, increased parasympathetic and reduced sympathetic modulation, lower cerebral blood flow velocity, intact cerebral autoregulation and maintenance of baroreflex functionality, as well as losses in systemic bodyweight and adipose tissue. Together, these findings illustrate novel insights into human adaptation across multiple body systems in response to multiday hyperbaric saturation.
multiday
Very long endurance running events can be divided into three broad categories: the traditional 26.2-mile (42.2 km) marathon, the ultramarathon, defined as any event longer than the marathon, and true multiday events, which begin with the 48-hour event and can stretch out almost indefinitely, often ranging from six days to 3,000 miles (4,800 km) or longer.
Ultramarathons, of which multiday races are a subset, include events of any distance beyond the traditional marathon distance of 42.195 kilometres (26.219 mi). Common ultra events include 100-mile (160 km) and 100 kilometer races. Ultras are usually considered to include all events of 50 kilometers or longer. Depending on the degree of terrain difficulty, up to 30 hours or more is generally allowed for runners to complete typical ultras, for example the Badwater Ultramarathon.
Many multiday races are held on tracks or measured loops, which eases provision of aid station support for runners. Stage races are the alternative; these include point to point races such as the Trans-American races, which traverse the North American continent coast to coast, and the Gobi March,[1] a seven-day journey across the Gobi desert, the Kalahari Augrabies Extreme Marathon, a 7-day, 250 km trail event in the Kalahari Desert, and the Yukon Arctic Ultra, a 430/300/100/26 mile challenge crossing Yukon in the dead of winter.
Longer multiday races include the Trans-Europe race, which ran from Lisbon to Moscow in 2003, a distance of about 5,100 kilometers. These events take the runner to a different level, where the race becomes a way of life and where nutrition, sleep, energy and psychological states have to be carefully managed. The Self-Transcendence 3100 Mile Race is the longest certified footrace in the world.[1]
The golden era of multiday races stretches back to the 1870s and 1880s, when they were held on indoor tracks and offered substantial prizes. Known as pedestrians, these athletes established records which in some cases have stood until recently. In summer 1809 in Newmarket, England, Robert Barclay Allardice, better known as Captain Barclay, ran/walked one mile (1.6 km) for each consecutive hour, each consecutive day, totalling 1,000 miles (1,600 km).
The most common multiday race of the era was the six-day race, which ran from Monday to Saturday with Sunday being observed as a rest day. In 1878, Sir John Dugdale Astley was inspired to create a series of five international six-day races, in which competitors vied for the Astley Belt. Two early competitors were the American Edward Payson Weston, who covered 500 miles (800 km) in 6 days. The Englishman Charles Rowell covered 241 km in the first day of a 6-day races in the 1880s.
By the early 1890s, public enthusiasm for such events had moved into bicycle racing, and the multiday running craze came to an end. Interest grew again in the late 1920s, with the advent of Trans-America races. These events were transcontinental stage races that inspired a new generation to challenge the huge distance. There was little reward for these races in the long run, and it was not until the 1980s that interest re-awoke in true multi-day races. In 1980, San Francisco postal delivery worker Don Choi [fr] organized the first modern era six-day race, on a track in Woodside, California.
Customers should prepare for the potential of multiday power outages. When outages occur, Duke Energy is committed to restoring power as safely and quickly as possible, while keeping customers informed throughout the process. Line technicians do not perform elevated work in bucket trucks when winds (sustained or gusts) are above 30 miles per hour.
The increase in Tlim was accompanied by an increase in [HCO3-], suggesting that acidosis might be a limiting factor for exercise at CP. Prolonged NaHCO3 supplementation did not lead to a further increase in [HCO3-] due to the concurrent elevation in plasma volume. This may explain why Tlim remained unaltered despite the prolonged NaHCO3 supplementation period. Ingestion of one single NaHCO3 dose per day before the competition during multiday competitions or tournaments might be a valuable strategy for performance enhancement.
Thus, the purpose of this randomized, placebo-controlled, double-blind interventional crossover study was to investigate if multiday acute NaHCO3 supplementation in well-trained endurance athletes leads to changes in Tlim at CP during constant-load cycle ergometer trials on a day-to-day basis with daily acute NaHCO3vs. placebo supplementation for 5 days. Furthermore, we aimed to investigate if differences in Tlim can be explained by alterations in [HCO3-] and if the high amount of ingested Na+ influences plasma volume (PV) and thus [HCO3-]. Given that exercise at or above CP leads to muscle and blood acidification [6, 7], and that [HCO3-] increases extracellular buffer capacity [13], we hypothesized that consecutive, acute-load daily supplementation of NaHCO3 increases Tlim relative to placebo. We assumed that an increase in [HCO3-] after the first intake is responsible for the rise in Tlim. Since during multiday NaHCO3 intake, a high amount of Na+ is ingested and absorbed, detrimental effects on endurance performance are possible. In fact, a higher [Na+] leads to water retention and thereby results in PV expansion [20]. An increase in PV decreases blood ion concentrations, and as such results in a diminished [HCO3-], which in turn could counteract the benefits associated with NaHCO3 intake. It is therefore questionable, whether [HCO3-] can be increased beyond the concentration reached after the first day of supplementation on all subsequent days of supplementation. Consequently, we hypothesized that PV expands following a high Na+ intake, limiting any further increase in [HCO3-], and consequently Tlim, beyond that observed after the first day of supplementation.
Several new findings have been observed in this randomized, placebo-controlled, double-blind interventional crossover investigation. First, multiday NaHCO3 supplementation for 5 days increased Tlim at CP on each day relative to placebo in highly trained athletes. Second, there was no difference in the increased Tlim over the 5 days of supplementation with NaHCO3 or NaCl. Third, the increase in Tlim was paralleled by increases in [HCO3-], pH and ABE. Fourth, [HCO3-] and [Na+] in the blood stabilized over time in the NaHCO3 condition. Fifth, calculated PV increased during the NaHCO3 more than in the placebo intervention.
In conclusion, multiple acute, consecutive day NaHCO3 supplementation led to an increase in Tlim at CP after the first bolus intake. However, while Tlim remained elevated in the NaHCO3 condition, it was not further altered with prolonged NaHCO3 supplementation. The increase in Tlim was accompanied by a higher [HCO3-] gradient between the blood and the intramyocellular compartment, which stabilized over time in the NaHCO3 intervention. In contrast to the theoretical CP-model, where metabolites should reach a steady state during exercise at CP, and consequently, buffer substances should be ineffective in enhancing Tlim, we showed that in practice Tlim can be increased with NaHCO3 supplementation. Furthermore, the high amount of ingested Na+ caused a sustained elevation in PV, which inhibited a further increase in [HCO3-], and consequently limited the performance-enhancing effect. Therefore, this study indicates that NaHCO3 can be taken daily in multiday competitions or tournaments to maintain performance ability throughout the whole duration of the competition. 2ff7e9595c
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