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Physiological Reports May 2023Limited research exists examining how resistance training to failure affects applied outcomes and single motor unit characteristics in previously trained individuals.... (Randomized Controlled Trial)
Randomized Controlled Trial
Limited research exists examining how resistance training to failure affects applied outcomes and single motor unit characteristics in previously trained individuals. Herein, resistance-trained adults (24 ± 3 years old, self-reported resistance training experience was 6 ± 4 years, 11 men and 8 women) were randomly assigned to either a low-repetitions-in-reserve (RIR; i.e., training near failure, n = 10) or high-RIR (i.e., not training near failure, n = 9) group. All participants implemented progressive overload during 5 weeks where low-RIR performed squat, bench press, and deadlift twice weekly and were instructed to end each training set with 0-1 RIR. high-RIR performed identical training except for being instructed to maintain 4-6 RIR after each set. During week 6, participants performed a reduced volume-load. The following were assessed prior to and following the intervention: (i) vastus lateralis (VL) muscle cross-sectional area (mCSA) at multiple sites; (ii) squat, bench press, and deadlift one-repetition maximums (1RMs); and (iii) maximal isometric knee extensor torque and VL motor unit firing rates during an 80% maximal voluntary contraction. Although RIR was lower in the low- versus high-RIR group during the intervention (p < 0.001), total training volume did not significantly differ between groups (p = 0.222). There were main effects of time for squat, bench press, and deadlift 1RMs (all p-values < 0.05), but no significant condition × time interactions existed for these or proximal/middle/distal VL mCSA data. There were significant interactions for the slope and y-intercept of the motor unit mean firing rate versus recruitment threshold relationship. Post hoc analyses indicated low-RIR group slope values decreased and y-intercept values increased after training suggesting low-RIR training increased lower-threshold motor unit firing rates. This study provides insight into how resistance training in proximity to failure affects strength, hypertrophy, and single motor unit characteristics, and may inform those who aim to program for resistance-trained individuals.
Topics: Male; Humans; Adult; Female; Young Adult; Resistance Training; Quadriceps Muscle; Adaptation, Physiological; Acclimatization; Hypertrophy; Muscle Strength; Muscle, Skeletal
PubMed: 37144554
DOI: 10.14814/phy2.15679 -
Journal of Intelligence Sep 2021Cultural intelligence is one's ability to adapt when confronted with problems arising in interactions with people or artifacts of diverse cultures. In this study, we...
Cultural intelligence is one's ability to adapt when confronted with problems arising in interactions with people or artifacts of diverse cultures. In this study, we conduct an initial construct-validation and assessment of a maximum-performance test of cultural intelligence. We assess the psychometric properties of the test and also correlate the test with other measures with which it might be expected there would be some connection. We found that our test was internally consistent and correlated significantly with maximum-performance tests of abilities but generally less or not at all with typical-performance tests, including cultural intelligence and openness to experience. However, our test appears to be distinct in what it measures from the other tests of cognitive abilities. The results lead us to suggest that cultural intelligence may have both maximum-performance and typical-performance aspects.
PubMed: 34564293
DOI: 10.3390/jintelligence9030045 -
PeerJ 2023Calculating amino-acid substitution models that are specific for individual protein data sets is often difficult due to the computational burden of estimating large...
Calculating amino-acid substitution models that are specific for individual protein data sets is often difficult due to the computational burden of estimating large numbers of rate parameters. In this study, we tested the computational efficiency and accuracy of five methods used to estimate substitution models, namely Codeml, FastMG, IQ-TREE, P4 (maximum likelihood), and P4 (Bayesian inference). Data-specific substitution models were estimated from simulated alignments (with different lengths) that were generated from a known simulation model and simulation tree. Each of the resulting data-specific substitution models was used to calculate the maximum likelihood score of the simulation tree and simulated data that was used to calculate the model, and compared with the maximum likelihood scores of the known simulation model and simulation tree on the same simulated data. Additionally, the commonly-used empirical models, cpREV and WAG, were assessed similarly. Data-specific models performed better than the empirical models, which under-fitted the simulated alignments, had the highest difference to the simulation model maximum-likelihood score, clustered further from the simulation model in principal component analysis ordination, and inferred less accurate trees. Data-specific models and the simulation model shared statistically indistinguishable maximum-likelihood scores, indicating that the five methods were reasonably accurate at estimating substitution models by this measure. Nevertheless, tree statistics showed differences between optimal maximum likelihood trees. Unlike other model estimating methods, trees inferred using data-specific models generated with IQ-TREE and P4 (maximum likelihood) were not significantly different from the trees derived from the simulation model in each analysis, indicating that these two methods alone were the most accurate at estimating data-specific models. To show the benefits of using data-specific protein models several published data sets were reanalysed using IQ-TREE-estimated models. These newly estimated models were a better fit to the data than the empirical models that were used by the original authors, often inferred longer trees, and resulted in different tree topologies in more than half of the re-analysed data sets. The results of this study show that software availability and high computation burden are not limitations to generating better-fitting data-specific amino-acid substitution models for phylogenetic analyses.
Topics: Amino Acid Substitution; Bayes Theorem; Computer Simulation; Models, Genetic; Phylogeny; Proteins; Classification
PubMed: 37576497
DOI: 10.7717/peerj.15716 -
Journal of Stroke and Cerebrovascular... Oct 2021The relationship between maximum and comfortable gait speed in individuals with mild to moderate disability in the chronic phase of stroke is unknown.
BACKGROUND
The relationship between maximum and comfortable gait speed in individuals with mild to moderate disability in the chronic phase of stroke is unknown.
OBJECTIVE
This study examines the relationship between comfortable and maximum gait speed in individuals with chronic stroke and whether the relationship differ from that seen in a community-dwelling elderly population. Further, we investigate the influence of age, gender, time post-stroke and degree of disability on gait speed.
MATERIALS AND METHODS
Gait speed was measured using the 10-meter walk test (10MWT) and the 30-meter walk test (30MWT) in 104 older individuals with chronic stroke and 154 community-dwelling controls, respectively.
RESULTS
We found that the maximum gait speed in individuals with stroke could be estimated by multiplying the comfortable speed by 1.41. This relationship differed significantly from that of the control group, for which the corresponding factor was 1.20. In the stroke group, age, gender and time post-stroke did not affect the relationship, whereas the degree of disability was negatively correlated with maximum speed - but not when included in the multiple analysis. In the community-dwelling population, higher age and female gender had a negative relationship with maximum gait speed. When correcting for those parameters, the coefficient was 1.07.
CONCLUSIONS
The maximum gait speed in the chronic phase of stroke can be estimated by multiplying the individual's comfortable gait speed by 1.41. This estimation is not impacted by age, gender, degree of disability and time since stroke. A similar but weaker relationship can be seen in the community-dwelling controls.
Topics: Aged; Aged, 80 and over; Case-Control Studies; Chronic Disease; Disability Evaluation; Female; Functional Status; Humans; Independent Living; Male; Middle Aged; Stroke; Walk Test; Walking Speed
PubMed: 34375858
DOI: 10.1016/j.jstrokecerebrovasdis.2021.106023 -
Respiratory Care May 2021This systematic literature review summarizes the impact of smoking on maximal oxygen uptake (maximum [Formula: see text]). (Review)
Review
BACKGROUND
This systematic literature review summarizes the impact of smoking on maximal oxygen uptake (maximum [Formula: see text]).
METHODS
Full-text articles were retrieved if the abstract met the assigned criteria. A total of 9 articles were included in the final review based on the inclusion and exclusion criteria. These included articles assessed the effects of tobacco smoking on maximum [Formula: see text] values.
RESULTS
Half of the articles reported a significant difference in maximum [Formula: see text] scores between smokers and nonsmokers, with smokers having a lower maximum [Formula: see text]. The other half of the articles did not identify significant differences between smokers and nonsmokers. One study found a significant difference in maximum [Formula: see text] in only one age group (ie, 20-29 y), but not any of the other age groups.
CONCLUSIONS
More research is needed on the effects of smoking on maximum [Formula: see text] to better understand any relationships or causations.
Topics: Humans; Oxygen; Oxygen Consumption; Smoking; Tobacco Smoking
PubMed: 33593934
DOI: 10.4187/respcare.08406 -
Journal of Food Protection Sep 2021Histamine is a biogenic amine and a food safety hazard, and it is the only biogenic amine regulated by statute or hazard analysis and critical control point guidance.... (Review)
Review
Histamine is a biogenic amine and a food safety hazard, and it is the only biogenic amine regulated by statute or hazard analysis and critical control point guidance. This article reviews the regulations for histamine levels in fish in countries around the world, including maximum limits or levels and sampling procedures in different fish preparations. The maximum histamine levels, sampling plans, and fish products are listed. The country-by-country regulations for maximum histamine acceptance levels in some food products vary by a factor of 8, from 50 ppm in some countries to a maximum of 400 ppm in other countries. For similar food products, the maximum histamine levels vary by a factor of 4 (from 50 ppm to 200 ppm) in, for example, fresh tuna. The country-by-country sampling plans vary widely as well, and these, too, are covered in detail.
Topics: Animals; Biogenic Amines; Fish Products; Fishes; Histamine; Tuna
PubMed: 33984131
DOI: 10.4315/JFP-21-129 -
Zoo Biology Nov 2022Little is known about the biology of grey-cheeked and black crested mangabeys (Lophocebus albigena and Lophocebus aterrimus, respectively). As these primates face...
Little is known about the biology of grey-cheeked and black crested mangabeys (Lophocebus albigena and Lophocebus aterrimus, respectively). As these primates face threats in the wild, well-monitored zoo-housed populations with up to date registries are becoming increasingly valuable to acquire species knowledge and to support conservation efforts. We used international studbooks to extract demographic and genetic information on 519 mangabeys to investigate how life history and parent-related variables influence maximum longevity and juvenile mortality. Generalized linear mixed models, as well as survival analyses, were applied. Results showed that females lived significantly longer than males, which is not uncommon in primates. Furthermore, our results indicated that the maximum longevity is lower for individuals living in European zoos versus individuals from North American zoos, which may be due to a combination of environmental differences and potential founder effects. We also show that the maternal maximum longevity is positively related to the maximum longevity of the offspring, which may be explained by the inheritance of "good genes". However, the age of the mother at the moment of birth was negatively related to the maximum longevity of the offspring, which contradicts literature that states that, in primates, more experienced and thus older mothers will raise their offspring better than less experienced mothers. Instead, it is more likely that an "optimal age range" exists for breeding mothers. Our study provides insights into the population biology of captive mangabeys and may be helpful for identifying future research priorities to optimize primate health and welfare directly ex situ, and indirectly in situ.
Topics: Animals; Cercocebus; Animals, Zoo
PubMed: 35365901
DOI: 10.1002/zoo.21690 -
Orphanet Journal of Rare Diseases May 2023Impairment of bulbar function in adult individuals with spinal muscular atrophy (SMA) usually is not assessed by established motor scores. Measurements of oral function...
BACKGROUND
Impairment of bulbar function in adult individuals with spinal muscular atrophy (SMA) usually is not assessed by established motor scores. Measurements of oral function including quantitative muscle and endurance tests are able to detect subtle changes. The aim of this study was to systematically evaluate the measurement of maximum bite force and endurance, maximum tongue pressure and endurance, as well as maximum mouth opening in adult individuals with SMA types 2 and 3.
METHODS
Data from oral function tests in 43 individuals were analyzed. Differences in oral function between individuals with different SMA types and numbers of SMN2 copies were tested. Spearman´s rho correlations among oral function measures themselves as well as with established clinical outcome scales were analyzed.
RESULTS
The absolute maximum measures of oral function (maximum bite force, maximum tongue pressure, maximum mouth opening) were able to discriminate between individuals with different SMA types, individuals with a different number of SMN2 copies and with different walking abilities. The pairwise correlations of the absolute maximum measures of oral function were fair to moderate in size; the same was true for their correlations with the established motor scores. All correlations assessing endurance measures of oral function were weaker and statistically insignificant.
CONCLUSIONS
Among the oral function tests maximum tongue pressure and maximum mouth opening are particulary promising as clinical and sensitive outcome measures for clinical trials. Oral function tests may supplement existing motor scores, in particular concerning specific questions about bulbar function or in severely affected non-ambulatory individuals where mild (treatment-related) changes would otherwise remain undetected. Trial registration DRKS, DRKS00015842. Registered 30 July 2019, https://drks.de/search/de/trial/DRKS00015842.
Topics: Humans; Adult; Pressure; Tongue; Muscular Atrophy, Spinal; Spinal Muscular Atrophies of Childhood; Outcome Assessment, Health Care
PubMed: 37138365
DOI: 10.1186/s13023-023-02688-4 -
Journal of Intelligence Aug 2022We administered both maximum-performance and typical-performance assessments of cultural intelligence to 114 undergraduates in a selective university in the Northeast of...
We administered both maximum-performance and typical-performance assessments of cultural intelligence to 114 undergraduates in a selective university in the Northeast of the United States. We found that cultural intelligence could be measured by both maximum-performance and typical-performance tests of cultural intelligence. Cultural intelligence as assessed by a maximum-performance measure is largely distinct from the construct as assessed by a typical-performance measure. The maximum-performance test, the Sternberg Test of Cultural Intelligence (SCIT), showed high internal consistency and inter-rater reliability. Sections with problems from two content domains-Business (SCIT-B) and Leisure (SCIT-L) activities-were highly intercorrelated, suggesting they measured largely the same construct. The SCIT showed substantial correlations with another maximum-performance measure of cultural intelligence, Views-on-Culture. It also was correlated, at more modest levels, with fluid intelligence and personal intelligence tests. Factorially, the (a) maximum-performance cultural intelligence tests, (b) typical-performance cultural intelligence test and a test of openness to experience, and (c) fluid intelligence tests formed three separate factors.
PubMed: 35997410
DOI: 10.3390/jintelligence10030054 -
Frontiers in Plant Science 2021Biological nitrogen (N) fixation is the most relevant process in soybeans ( L.) to satisfy plant N demand and sustain seed protein formation. Past studies describing N...
Biological nitrogen (N) fixation is the most relevant process in soybeans ( L.) to satisfy plant N demand and sustain seed protein formation. Past studies describing N fixation for field-grown soybeans mainly focused on a single point time measurement (mainly toward the end of the season) and on the partial N budget (fixed-N minus seed N removal), overlooking the seasonal pattern of this process. Therefore, this study synthesized field datasets involving multiple temporal measurements during the crop growing season to characterize N fixation dynamics using both fixed-N (kg ha) and N derived from the atmosphere [Ndfa (%)] to define: (i) time to the maximum rate of N fixation (β), (ii) time to the maximum Ndfa (α), and (iii) the cumulative fixed-N. The main outcomes of this study are that (1) the maximum rate of N fixation was around the beginning of pod formation (R3 stage), (2) time to the maximum Ndfa (%) was after full pod formation (R4), and (3) cumulative fixation was positively associated with the seasonal vapor-pressure deficit (VPD) and growth cycle length but negatively associated with soil clay content, and (4) time to the maximum N fixation rate (β) was positively impacted by season length and negatively impacted by high temperatures during vegetative growth (but positively for VPD, during the same period). Overall, variation in the timing of the maximum rate of N fixation occurred within a much narrower range of growth stages (R3) than the timing of the maximum Ndfa (%), which varied broadly from flowering (R1) to seed filing (R5-R6) depending on the evaluated studies. From a phenotyping standpoint, N fixation determinations after the R4 growth stage would most likely permit capturing both maximum fixed-N rate and maximum Ndfa (%). Further investigations that more closely screen the interplay between N fixation with soil-plant-environment factors should be pursued.
PubMed: 34691106
DOI: 10.3389/fpls.2021.727021