Untrained Subjects Research Articles

Do Heat And Exercise Training Elicit Similar Adaptations In Vascular Function During Rest And Exercise?

Heat, the major byproduct of exercise, may mediate many of the vascular adaptations that come from exercise, making heat therapy a potential alternative to exercise in situations where exercise is not possible. PURPOSE: Compare the effects of 6 weeks of exercise or heat training on resistance artery function at rest and during exercise. METHODS: Thirty-five (18 female) untrained subjects completed either 6-weeks of high-intensity, single-leg, knee-extension exercise (40 mins, 3x per week, n = 11), localized heat training (pulsed short-wave diathermy for 120 minutes, 3x per week n = 13), or a sham heat training protocol (120 minutes, 3x per week, n = 11). Vascular function was measured before and after the training. Specifically, resistance artery function was assessed at rest with the passive leg movement induced hyperemia (PLM). Leg blood flow and vascular conductance were also measured with Doppler Ultrasound and finometry during submaximal, steady-state knee extension (KE) exercise at 10 W and during a maximal graded KE exercise test. RESULTS: Resistance artery function, assessed by peak blood flow during PLM, increased in the exercise (~10.5% increase, P = 0.009) and heating groups (~8.5% increase, P = 0.044) to the same extent (P = 0.625); but tended to decrease in the sham group (P = 0.087). While blood flow during submaximal KE (10 W) did not change in any group, vascular conductance at 10 W tended to increase in the exercise group (19%, P = 0.056) and the heat group (16%, P = 0.036), but did not change in the sham group (P = 0.915). Likewise, maximum vascular conductance during KE significantly increased by ~25% in the exercise (P = 0.030) and heat (P = 0.012) groups but did not change in the sham group (P = 0.699). Importantly, the magnitude of change in resistance artery function, assessed by PLM, was related to the change in maximal vascular conductance (r = 0.50, P = 0.006). Maximum power achieved during KE only increased in the exercise group (~27%, P = 0.001). CONCLUSIONS: Localized heat therapy improved resistance artery function and exercise vascular conductance to the same extent as exercise training but did not yield significant improvements in exercise performance. Thus, heat therapy may be used to achieve many of the vascular benefits of exercise.

숙련자와 비숙련자의 8주간의 저항 훈련 후에 신체조성과 1 RM 근력의 변화

The purpose of this study was to investigate the analysis of between body composition and 1 RM muscle strength before and after resistance training (RT) in Trained and Untrained Subjects. A total of 52 healthy adults were divided into men trained group (MTG; n=10), woman trained group (WTG, n=10), men untrained group (MUG, n=19) and woman untrained group (WUG, n=13). MTG and WTG were performed high intensity (6 RM) resistance training at least twice a week for six months, and MUG and WUG were not performed RT in the last year. Body composition (weight, muscle mass, lean body mass, body fat, BMI) and 1 RM muscle strength (leg pressure; LP, bench pressure; BP, and late full down; LD) were measured before and after RT. The 1 RM muscle strength of LP and BP were significantly different between groups, and the 1 RM muscle strength of BP and LD were significantly different between times. In addition, the 1 RM muscle strength of BP was significant increased after compared with that at before RT. Therefore, it was confirmed that 1 RM muscle strength increased in Untrained than in Trained Subjects, but 1 RM muscle strength can be improved along with an increase in body weight for Trained Subjects.

Adaptive binary multi-objective harmony search algorithm for channel selection and cross-subject generalization in motor imagery-based BCI

Objective. Multi-channel electroencephalogram data containing redundant information and noise may result in low classification accuracy and high computational complexity, which limits the practicality of motor imagery (MI)-based brain-computer interface (BCI) systems. Therefore, channel selection can improve BCI performance and contribute to user convenience. Additionally, cross-subject generalization is a key topic in the channel selection of MI-based BCI. Approach. In this study, an adaptive binary multi-objective harmony search (ABMOHS) algorithm is proposed to select the optimal set of channels. Furthermore, a new adaptive cross-subject generalization model (ACGM) is proposed. Three public MI datasets were used to validate the effectiveness of the proposed method. Main results. The Wilcoxon signed-rank test was performed on the test accuracies, and the results indicated that the ABMOHS method significantly outperformed all channels (p< 0.001), the C3–Cz–C4 channels (p< 0.001), and 20 channels (p< 0.001) in the sensorimotor cortex. The ABMOHS algorithm based on Fisher’s linear discriminant analysis (FLDA) and support vector machine (SVM) classifiers greatly reduces the number of selected channels, especially for larger channel sizes (Dataset 2), and obtains a comparative classification performance. Although there was no significant difference in test classification performance between ABMOHS and non-dominated sorting genetic algorithm II (NSGA-II) when FLDA and SVM were used, ABMOHS required less computational time than NSGA-II. Furthermore, the number of channels obtained by ABMOHS algorithm were significantly smaller than those obtained by common spatial pattern-Rank and correlation-based channel selection algorithm. Additionally, the generalization of ACGM to untrained subjects shows that the mean test classification accuracy of ACGM created by a small sample of trained subjects is significantly better than that of Special-16 and Special-32. Significance. The proposed method can reduce the calibration time in the training phase and improve the practicability of MI-BCI.

Sustained Endurance Training Leads to Metabolomic Adaptation.

Endurance training induces several adaptations in substrate metabolism, especially in relation to glycogen conservation. The study aimed to investigate differences in the metabolism of lipids, lipid-like substances, and amino acids between highly trained and untrained subjects using targeted metabolomics. Depending on their maximum relative oxygen uptake (VO2max), subjects were categorized as either endurance-trained (ET) or untrained (UT). Resting blood was taken and plasma isolated. It was screened for changes of 345 metabolites, including amino acids and biogenic amines, acylcarnitines, glycerophosphocholines (GPCs), sphingolipids, hexoses, bile acids, and polyunsaturated fatty acids (PUFAs) by using liquid chromatography coupled to tandem mass spectrometry. Acylcarnitine (C14:1, down in ET) and five GPCs (lysoPC a C18:2, up in ET; PC aa C42:0, up in ET; PC ae C38:2, up in ET; PC aa C38:5, down in ET; lysoPC a C26:0, down in ET) were differently regulated in ET compared to UT. TCDCA was down-regulated in athletes, while for three ratios of bile acids CA/CDCA, CA/(GCA+TCA), and DCA/(GDCA+TDCA) an up-regulation was found. TXB2 and 5,6-EET were down-regulated in the ET group and 18S-HEPE, a PUFA, showed higher levels in 18S-HEPE in endurance-trained subjects. For PC ae C38:2, TCDCA, and the ratio of cholic acid to chenodeoxycholic acid, an association with VO2max was found. Numerous phospholipids, acylcarnitines, glycerophosphocholines, bile acids, and PUFAs are present in varying concentrations at rest in ET. These results might represent an adaptation of lipid metabolism and account for the lowered cardiovascular risk profile of endurance athletes.

Effects of Variable-Resistance Training Versus Constant-Resistance Training on Maximum Strength: A Systematic Review and Meta-Analysis.

Greater muscular strength is generally associated with superior sports performance, for example, in jumping, sprinting, and throwing. This meta-analysis aims to compare the effects of variable-resistance training (VRT) and constant-resistance training (CRT) on the maximum strength of trained and untrained subjects. PubMed, Web of Science, and Google Scholar were comprehensively searched to identify relevant studies published up to January 2022. Fourteen studies that met the inclusion criteria were used for the systematic review and meta-analysis. Data regarding training status, training modality, and type of outcome measure were extracted for the analyses. The Cochrane Collaboration tool was used to assess the risk of bias. The pooled outcome showed improved maximum strength with VRT, which was significantly higher than that with CRT (ES = 0.80; 95% CI: 0.42–1.19) for all the subjects. In addition, trained subjects experienced greater maximum-strength improvements with VRT than with CRT (ES = 0.57; 95% CI: 0.22–0.93). Based on subgroup analyses, maximum-strength improvement with a VRT load of ≥80% of 1 repetition maximum (1RM) was significantly higher than that with CRT (ES = 0.76; 95% CI: 0.37–1.16) in trained subjects, while no significant differences were found between VRT and CRT for maximum-strength improvement when the load was <80% (ES = 0.00; 95% CI: −0.55–0.55). The untrained subjects also achieved greater maximum strength with VRT than with CRT (ES = 1.34; 95% CI: 0.28–2.40). Interestingly, the improved maximum strength of untrained subjects with a VRT load of <80% of 1RM was significantly higher than that with CRT (ES = 2.38; 95% CI: 1.39–3.36); however, no significant differences were noted between VRT and CRT when the load was ≥80% of 1RM (ES = −0.04; 95% CI: −0.89–0.81). Our findings show that subjects with resistance training experience could use a load of ≥80% of 1RM and subjects without resistance training experience could use a load of <80% of 1RM to obtain greater VRT benefits.

Training naive subjects in using micro-phenomenological self-inquiry to investigate pain and suffering during headaches.

Micro-phenomenology is a method that generates rich and reliable reports of singular experiences in their pre-reflective dimension. Usually it is employed using a second-person interviewer. In this study we attempted to train naïve subjects in using self-inquiry version of the method. 13 subjects met twice over the course of one week, investigating their experiences of headaches, looking specifically into the pain experience itself, the experience of suffering, and the experience of absence of suffering. The analysis showed that the subject reports increase the richness of description, measured by the increase in the amount of categories described and the number of words needed to give an on target description. The analysis, informed by the participant's ideas, showed that it was possible to distinguish the experience of pain from the experience of suffering. We compare the analysis to other phenomenological studies of headaches. This reveals the strength and weakness of the micro-phenomenological method: By de-focusing on contextual factors it enables in-depth descriptions of singular moments of experience, but the bracketing of interpretations may result in overlooking overarching meaning dimensions. We conclude that micro-phenomenological self-inquiry may potentially be employed successfully in a clinical setting with initially untrained subjects for describing certain kinds of experiences and answering complex phenomenological questions.

A novel channel selection scheme for olfactory EEG signal classification on Riemannian manifolds

Objective. The classification of olfactory-induced electroencephalogram (olfactory EEG) signals has potential applications in disease diagnosis, emotion regulation, multimedia, and so on. To achieve high-precision classification, numerous EEG channels are usually used, but this also brings problems such as information redundancy, overfitting and high computational load. Consequently, channel selection is necessary to find and use the most effective channels. Approach. In this study, we proposed a multi-strategy fusion binary harmony search (MFBHS) algorithm and combined it with the Riemannian geometry classification framework to select the optimal channel sets for olfactory EEG signal classification. MFBHS was designed by simultaneously integrating three strategies into the binary harmony search algorithm, including an opposition-based learning strategy for generating high-quality initial population, an adaptive parameter strategy for improving search capability, and a bitwise operation strategy for maintaining population diversity. It performed channel selection directly on the covariance matrix of EEG signals, and used the number of selected channels and the classification accuracy computed by a Riemannian classifier to evaluate the newly generated subset of channels. Main results. With five different classification protocols designed based on two public olfactory EEG datasets, the performance of MFBHS was evaluated and compared with some state-of-the-art algorithms. Experimental results reveal that our method can minimize the number of channels while achieving high classification accuracy compatible with using all the channels. In addition, cross-subject generalization tests of MFBHS channel selection show that subject-independent channels obtained through training can be directly used on untrained subjects without greatly compromising classification accuracy. Significance. The proposed MFBHS algorithm is a practical technique for effective use of EEG channels in olfactory recognition.

From questionnaire to interview in survey research: Paul F. Lazarsfeld and the Wirtschaftspsychologische Forschungsstelle in interwar Vienna

ABSTRACT In interwar Vienna, Paul F. Lazarsfeld and his colleagues developed an approach to survey research that used the questionnaire and the direct, face-to-face interview to gather data about subjective experience for aggregative analysis. For these young researchers, the questionnaire-based interview emerged from a contradictory set of Central European intellectual traditions and political concerns. Enthusiasm on the political left for quantification and the gathering of social data encouraged survey research; yet, local political allies and intellectual mentors also opposed the study of individual attitudes and the quantitative aggregation of such material. Academic psychology legitimized the use of “introspection” and facilitated the extension of this method to populations of untrained subjects. The methodological concept of the “model” helped overcome the Verstehen/Erklären dichotomy within debates over the proper methods of the human and social sciences. This article examines methodological and philosophical statements, study designs, and questionnaires to explain how the interview gained particular importance within this setting.

66-LB: System Performance of an Integrated Blood Glucose Monitoring Device Developed to Reduce Common Barriers to Checking Glucose

The POGO Automatic® Blood Glucose Monitoring System miniaturizes individual items required to perform a blood glucose test (lancet, lancing device, test strip, etc.) and integrates those components into a multi-test cartridge that pairs to a handheld device, addressing many perceived checking barriers. This device allows the user to place and hold a finger on the device while the blood sample is acquired and moved to the reagent pad automatically for quantitation. Performance testing was conducted on the device to assess accuracy, precision, and tolerance to hematocrit and interfering substances. Fingerstick capillary blood was collected from 285 untrained subjects with either type 1 or type 2 diabetes at two sites (age 21-95, mean 58.1; 50.2% female, 84.9% Caucasian) and run on a YSI 2300 analyzer while the subject used the system as designed to obtain a glucose result. When compared against the YSI reference result, 264/277 (95.3%) results were within ± 15 mg/dL or 15% of the reference reading, and 275/277 (99.3%) results were within ± 15 mg/dL or 20% of the reference reading. Precision testing was conducted by running 300 tests using venous blood at each of five glucose levels across the dynamic range, achieving CVs ranging from 2.3%-3.4%. Hematocrit tolerance was evaluated using venous whole blood manipulated into a matrix of seven hematocrit levels (20%-60%) ; each hematocrit was tested across the dynamic range. No mean bias versus YSI at any test condition exceeded 7.5%, and at least 95% of all tests at each condition were within 15% of the YSI reference value. Twenty-three substances, including acetaminophen, ascorbic acid, and maltose, were tested at both therapeutic and toxic concentrations to determine potential interference with measurement accuracy. For all substances tested, the entire 95% confidence interval for interferent bias was within ± 15%, and the average bias was within ± 10% of results from the control sample. Disclosure M. Tomasco: Employee; Intuity Medical, Inc. J. M. Davis: None. P. D. Reynolds: Employee; Intuity Medical, Inc. R. Escutia: Employee; Intuity Medical, Inc. J. N. Perry: Employee; Intuity Medical, Inc. T. O’donnell: Employee; Intuity Medical, Inc. R. P. Hesley: Employee; Intuity Medical, Inc.

Aerosol particle emission increases exponentially above moderate exercise intensity resulting in superemission during maximal exercise

Many airborne pathogens such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are transmitted indoors via aerosol particles. During exercise, pulmonary ventilation can increase over 10-fold, and therefore, exercisers will exhale a greater volume of aerosol-containing air. However, we currently do not know how exercise affects the concentration of aerosol particles in exhaled air and the overall emission of aerosol particles. Consequently, we developed a method to measure in parallel the concentration of aerosol particles in expired air, pulmonary ventilation, and aerosol particle emission at rest and during a graded exercise test to exhaustion. We used this method to test eight women and eight men in a descriptive study. We found that the aerosol particle concentration in expired air increased significantly from 56 ± 53 particles/liter at rest to 633 ± 422 particles/liter at maximal intensity. Aerosol particle emission per subject increased significantly by a factor of 132 from 580 ± 489 particles/min at rest to a super emission of 76,200 ± 48,000 particles/min during maximal exercise. There were no sex differences in aerosol particle emission, but endurance-training subjects emitted significantly more aerosol particles during maximal exercise than untrained subjects. Overall, aerosol particle emission increased moderately up to an exercise intensity of ∼2 W/kg and exponentially thereafter. Together, these data might partly explain superspreader events especially during high-intensity group exercise indoors and suggest that strong infection prevention measures are needed especially during exercise at an intensity that exceeds ∼2 W/kg. Investigations of influencing factors like airway and whole-body hydration status during exercise on aerosol particle generation are needed.

Effects of a 6-Month Aerobic Exercise Intervention on Mood and Amygdala Functional Plasticity in Young Untrained Subjects.

Acute exercise has beneficial effects on mood and is known to induce modulations in functional connectivity (FC) within the emotional network. However, the long-term effects of exercise on affective brain circuits remain largely unknown. Here, we investigated the effects of 6 months of regular exercise on mood, amygdala structure, and functional connectivity. This study comprised N = 18 healthy sedentary subjects assigned to an intervention group (IG; 23.9 ± 3.9 years; 3 trainings/week) and N = 10 subjects assigned to a passive control group (CG; 23.7 ± 4.2 years). At baseline and every two months, performance diagnostics, mood questionnaires, and structural and resting-state-fMRI were conducted. Amygdala-nuclei segmentation and amygdala-to-whole-brain FC analysis were performed. Linear mixed effects models and correlation analyses were conducted between FC, relVO2max, and mood scores. Data showed increases in relVO2max exclusively in the IG. Stronger anticorrelation in amygdala-precuneus FC was found, along with a stronger positive correlation in the amygdala-temporal pole FC in the IG after 4 and 6 months, while mood and amygdala volume did not reveal significant interactions. The relVO2max/amygdala-temporal pole FC correlated positively, and the amygdala-precuneus/amygdala-temporal pole FC correlated negatively. Findings suggest that exercise induced long-term modulations of the amygdala FC with the precuneus and temporal pole, shedding light on potential mechanisms by which exercise has positive influences on mood-related networks, typically altered in affective disorders.

Stabilization of an unstable equilibrium of a balance platform due to short-term training

We study experimentally and numerically the dynamics of a balance platform during a short-term training. The results of experiments with sixteen untrained subjects and a developed empirical biomechanical model exhibit the coexistence of three attractors under adaptive control of multistability. During the experiments, we measure the balance bar angle, angular velocity, and angular acceleration. Simultaneously, superficial electromyography (EMG) is recorded on the flexors and extensors of the ankle and knee joints. Phase-space analysis of the platform movement shows that the time the platform spends near the unstable equilibrium correlates with the average muscle activity. We also observe that the balance platform dynamics differs when the subject starts balancing with his/her dominant or non-dominant leg. In addition, we find that subjects with better symmetry between the strength of dominant and non-dominant legs demonstrate higher training efficiency. Therefore, the balance control efficiency can be enhanced by training muscles of the non-dominant leg. The results of numerical simulations are in good agreement with experiments.

Sub Maximal Ergospirometry Parameters in Untrained Non-Frail Octogenarian Subjects.

Background and Objectives: The prevalence of chronic diseases increases with age, and in octogenarian elderly, a cardiorespiratory test with gas analysis is more effective in determining the risk of mortality than applying the conventional risk factors. Materials and Methods: 25 untrained non-frail octogenarian subjects (four men) performed a submaximal test with gas analysis, which was stopped after the second ventilatory threshold (VT2) was reached. The variables analyzed were oxygen consumption at the first threshold (VO2 VT1); ventilatory class (VE/VCO2); oxygen uptake efficiency slope (OUES); cardiorespiratory optimal point (COP); oxygen pulse difference between VT2 and VT1 (diff. VO2/HR VT2-VT1). Results: the variables were classified categorically based on cut-off points present in the literature, where the variable with the highest percentage of altered cases was dif. VO2/HR VT2-VT1 at 48%; followed by VO2 VT1 at 40%, OUES at 36%, COP at 32%, and VE/VCO2 at 24%. Chi-square analysis between the measured parameters defined that normal and altered variables were related to each other, except for the variable VE/VCO2 and OUES. Conclusions: it was found that the main altered variable was the oxygen pulse and the least altered variable was VCO2/VCO2; there was only a statistically significant difference in a pair of OUES vs. VE/VCO2 variables.

Impact of an Agriphotovoltaic System on Metabolites and the Sensorial Quality of Cabbage (Brassica oleracea var. capitata) and Its High-Temperature-Extracted Juice

To date, the impacts of agriphotovoltaic (APV) condition on the production yield of crop have been studied; however, the effect of APV production on the sensorial quality and consumer acceptability of the produce remains unexplored. Therefore, to address this knowledge gap, we cultivated “Winter Storm” cabbage under solar panels (20.16 kW) and in open field in 2020. The weight and diameter reduction rate of fresh cabbage grown under APV condition compared to open-field conditions were 9.7% and 1.2%, respectively. The levels of glucosinolates and their hydrolysis products were not significantly different in the fresh cabbage between the two conditions. The amount of volatile organic compounds, which may affect the perception of smell, were significantly higher in the cabbage juice prepared from the ones grown in open-field conditions than in the juice prepared from cabbages grown under APV conditions (n = 3, p < 0.01). However, untrained subjects could not distinguish the difference in the quality of the 2 sets of cabbage juices in the triangle test (n = 70, p = 0.724). Regardless of the distinguishing features of color, aroma, and taste, the subjects did not have any preference between the two different cabbage juices.

Design, Development and Validation of a Knee Brace to Standardize the US Imaging Evaluation of Knee Osteoarthritis.

Objective: A repeatable and reliable follow-up of knee injuries would be desirable to prevent delayed diagnosis and to monitor the efficacy of the applied treatment over time. Ultrasound (US) techniques are an attractive option to this purpose, since they are safe, low-cost and non-invasive. However, its use in the clinical practice is limited by the high dependency on the operator’s experience. Hence, the objective of this study is to provide a standardization of the US image acquisition process for knee osteoarthritis (OA) allowing an extended clinical use of US technologies in this domain. Methods: Clinical specifications were provided by expert musculoskeletal radiologists thus identifying the subject poses and the US probe positions needed to evaluate the cartilage structure, signs of synovitis and joint effusion. Such considerations were used to derive the technical requirements needed for the development of a wearable brace equipped with specific openings to guide the correct placement of the probe. The feasibility of the developed wearable brace was tested on three healthy volunteers, which were asked to acquire informative US images, similar to the reference images performed by the musculoskeletal radiologist. Results: Thanks to the knee brace, the untrained subjects were able to self-acquire informative B-mode images comparable to the corresponding images acquired by an expert clinician. Discussion/Conclusion: The use of a knee brace intended for knee OA US diagnosis demonstrated the possibility to standardize the acquisition protocol and make its application achievable also for untrained subjects, representing a key step toward tele-ultrasonography.

Ameliorating Effects of Lifelong Physical Activity on Healthy Aging and Mitochondrial Function in Human White Adipose Tissue.

Growing old is patently among the most prominent risk factors for lifestyle-related diseases and deterioration in physical performance. Aging in particular affects mitochondrial homeostasis, and maintaining a well-functioning mitochondrial pool is imperative in order to avoid age-associated metabolic decline. White adipose tissue (WAT) is a key organ in energy balance, and impaired mitochondrial function in adipocytes has been associated with increased low-grade inflammation, altered metabolism, excessive reactive oxygen species (ROS) production, and an accelerated aging phenotype. Exercise training improves mitochondrial health but whether lifelong exercise training can sufficiently maintain WAT mitochondrial function is currently unknown. Therefore, to dissect the role and dose-dependence of lifelong exercise training on aging WAT metabolic parameters and mitochondrial function, young and older untrained, as well as moderately and highly exercise trained older male subjects were recruited and abdominal subcutaneous (s)WAT biopsies and venous blood samples were obtained to measure mitochondrial function and key metabolic factors in WAT and plasma. Mitochondrial intrinsic respiratory capacity was lower in sWAT from older than from young subjects. In spite of this, maximal mitochondrial respiration per wet weight, markers of oxidative capacity, and mitophagic capacity were higher in sWAT from the lifelong highly exercise trained group than all other groups. Furthermore, ROS emission was generally lower in sWAT from lifelong highly exercise trained subjects than older untrained subjects. Taken together, aging reduces intrinsic mitochondrial respiration in human sWAT, but lifelong high-volume exercise training increases oxidative capacity by increasing mitochondrial volume likely contributing to healthy aging.

The Association of Fatigue With Decreasing Regularity of Locomotion During an Incremental Test in Trained and Untrained Healthy Adults

Fatigue is a key factor that affects human motion and modulates physiology, biochemistry, and performance. Prolonged cyclic human movements (locomotion primarily) are characterized by a regular pattern, and this extended activity can induce fatigue. However, the relationship between fatigue and regularity has not yet been extensively studied. Wearable sensor methodologies can be used to monitor regularity during standardized treadmill tests (e.g., the widely used Bruce test) and to verify the effects of fatigue on locomotion regularity. Our study on 50 healthy adults [27 males and 23 females; <40 years; five dropouts; and 22 trained (T) and 23 untrained (U) subjects] showed how locomotion regularity follows a parabolic profile during the incremental test, without exception. At the beginning of the trial, increased walking speed in the absence of fatigue is associated with increased regularity (regularity index, RI, a. u., null/unity value for aperiodic/periodic patterns) up until a peak value (RI = 0.909 after 13.8 min for T and RI = 0.915 after 13.4 min for U subjects; median values, n. s.) and which is then generally followed (after 2.8 and 2.5 min, respectively, for T/U, n. s.) by the walk-to-run transition (at 12.1 min for both T and U, n. s.). Regularity then decreases with increased speed/slope/fatigue. The effect of being trained was associated with significantly higher initial regularity [0.845 (T) vs 0.810 (U), p < 0.05 corrected], longer test endurance [23.0 min (T) vs 18.6 min (U)], and prolonged decay of locomotor regularity [8.6 min (T) vs 6.5 min (U)]. In conclusion, the monitoring of locomotion regularity can be applied to the Bruce test, resulting in a consistent time profile. There is evidence of a progressive decrease in regularity following the walk-to-run transition, and these features unveil significant differences among healthy trained and untrained adult subjects.

Effect of Repetition Duration—Total and in Different Muscle Actions—On the Development of Strength, Power, and Muscle Hypertrophy: A Systematic Review

ABSTRACT The aim of this systematic review was (a) to identify the articles that have differentiated muscle action duration (MAD) in the eccentric (ECC) and concentric (CON) muscle action regimen during resistance training (RT) programs and (b) to analyze how MAD affects strength, power, and muscle hypertrophy adaptations. Twenty-four studies were included from 3 electronic databases. The results showed that the RT protocols with medium ECC MAD and fast CON MAD, specifically cadences 2–4/0/1/0, produced the highest improvement values for the development of maximum dynamic strength, both in trained (18–24%) and untrained subjects (10–14%). For the development of maximum power, a medium total repetition MAD of less than 4 seconds and slow total repetition MAD, less than 8 seconds, seems suitable for untrained and trained subjects, respectively, with the condition that CON MAD is explosive or fast (cadence 4–8/0/max-3/0). Finally, muscle hypertrophy could be improved with a total repetition MAD less than 8 seconds in both trained and untrained subjects. The optimal timing of each muscle action to maximize hypertrophic training results is still not entirely clear. In conclusion, the prescription of the MAD, total and phase specific, should be planned according to the adaptations desired in untrained and trained individuals.

숙련자와 비숙련자의 신체조성과 1RM 근력의 상관성 분석

The purpose of this study was to investigate the analysis of correlation between physical characteristics (muscle mass, body fat, lean body mass, BMI) and 1RM strength (bench press: BP, lat pull down: LD, leg press: LP, leg extension: LE, leg curl: LC) in trained and untrained subjects. Fifty-two (n=52) subjects were divided to trained group {TG, n=20, (M: 10, F: 10) trained 6 RM and more for 6 months} and untrained group {UTG, n=32 (M: 19, F: 13)}. All subjects were measured physical characteristics and 1RM strength. In men, Body fat was significantly lower in TG compared with UTG. 1RM of LP and BP in men and 1RM of LP, LC, BP and LD in women were significantly higher in TG compared with UTG. In TG men, 1RM of BP and LD were positively associated with weight, and 1RM of BP was positively associated with BMI. In UTG men, 1RM of LC was positively associated with height, and 1RM of LP and BP were positively associated with weight and muscle mass, and 1RM of LP, LC and BP were positively associated with lean body mass. In TG women, 1RM of LE and LC were positively associated with weight, and 1RM of LE, BP and LD were positively associated with muscle mass, and 1RM of LE, LC, BP and LD were positively associated with lean body mass, and 1RM of LE, LC and BP were positively associated with BMI. In UTG women, 1RM of LP and LD were positively associated with weight, and 1RM of LC and LD were positively associated with muscle mass and lean body mass. It seem that trained men use protagonist and synergist more efficiently than untrained subjects, and 1RM strength is thought to be different in muscle product in certain movements regardless of muscle size as well as muscle strength.

Rotator cuff strength is not augmented by blood flow restriction training

ObjectiveBlood flow restriction (BFR) training utilizes a tourniquet applied to the upper or lower extremities (UE or LE) to occlude blood flow while exercising. BFR training may help augment strength in muscles that are proximal to BFR cuff application. However, prior studies have failed to demonstrate augmented strength gains in the rotator cuff when the tourniquet is applied to the UE. The purpose of this study was to evaluate if a protocol consisting of LE exercises, performed with BFR, followed by rotator cuff exercises was superior in augmenting strength, and cross-sectional area (CSA) of the rectus femoris, in untrained subjects when compared to a non-BFR training group. DesignRandomized controlled trial. SettingUniversity. ParticipantsThirty-five subjects (mean age 25.8 ± 1.6 y) randomized to a BFR or non-BFR group. Main outcome measuresMuscular strength measured via hand held dynamometer and the CSA of the dominant rectus femoris was measured by diagnostic ultrasound. ResultsBoth groups experienced significant gains in LE and rotator cuff strength. Strength increased in the BFR group by 11.6% for the supraspinatus, 34.1% for shoulder ER, 23.4% for the quadriceps, and 17.1% for the hamstrings. Strength increased in the non-BFR group by 7.3% for the supraspinatus, 20% for shoulder ER, 12.8% for the quadriceps, and 10.7% for the hamstrings. However, there were no differences in strength gains between groups. Neither group experienced a significant increase in CSA for the rectus femoris. ConclusionThe BFR protocol used in this study did not augment strength for the rotator cuff in subjects who also performed LE exercises under occlusion.