Min Bouts Research Articles

The effects of acute exercise intensity on memory: Controlling for state-dependence.

The present experiment evaluated the effects of varying intensities of acute exercise on free-recall memory performance while controlling for potential state-dependent effects. Forty-eight young adults completed a within-subject experiment involving seven primary laboratory visits. The encoding and retrieval phases were matched or mismatched by taking place either during rest or during a less than 5-min bout of acute exercise, and at moderate or vigorous intensity. We did not find evidence that the effects of acute exercise on memory were state-dependent but instead demonstrated that memory recall was greater when memory retrieval occurred during vigorous-intensity exercise compared to rest. These findings have important implications for the strategic placement of exercise during the phases of memory (e.g., acquisition, storage, retrieval) to optimize memory performance and suggest boundary conditions of state-dependent learning. We discuss various theoretical accounts (e.g., shift in metabolic resources across brain regions) to explain these findings.

Light Walking Patterns and Postprandial Cardiometabolic Responses in Young Obese Adults: A Randomized Crossover Study.

Recent studies suggest that light-intensity physical activity may enhance cardiometabolic health and reduce mortality risk in adults. However, more information is required to understand the patterns of light-intensity physical activity and postprandial cardiometabolic health. This study examined the effects of different light-intensity walking patterns on postprandial cardiometabolic responses in young obese adults. A randomized crossover trial was conducted. The study was conducted in the laboratory. The study analyzed baseline (fasting) and 6-hour postprandial concentrations of glucose, insulin, triglycerides, and blood pressure (BP) in 16 young obese adults. Participants underwent four 7-hour experimental conditions with a 7-20-day washout period: uninterrupted sitting (SIT), 30-minute light-intensity walking (EX+SIT), 3-minute light-intensity walking every 30 minutes (BR), and 30-minute light-intensity walking with 3-minute light-intensity walking every 30 minutes (EX+BR). Incremental areas under the curve (iAUC) for each outcome and average BP were compared between SIT and walking conditions. Compared with SIT, all walking conditions reduced iAUCs for glucose and average diastolic BP (all p<0.05). Only EX+SIT and EX+BR reduced iAUCs for insulin (p<0.05). No significant differences were found for triglycerides iAUC and systolic BP between the four conditions (all p>0.05). All patterns of light-intensity walking reduced postprandial glucose concentrations and diastolic BP in young obese adults, suggesting benefits for glycemic control. Continuous 30-minute light-intensity walking alone, or combined with brief 3-min bouts also attenuated postprandial insulin concentrations, highlighting light-intensity walking as a promising strategy for improving cardiometabolic health in young obese adults.

Effect of Interrupting Prolonged Sitting with Frequent Activity Breaks on Postprandial Glycemia and Insulin Sensitivity in Adults with Type 1 Diabetes on Continuous Subcutaneous Insulin Infusion Therapy: A Randomized Crossover Pilot Trial.

Objective: This study examined acute effects of interrupting prolonged sitting with short activity breaks on postprandial glucose/insulin responses and estimations of insulin sensitivity in adults with type 1 diabetes (T1D). Method: In a randomized crossover trial, eight adults (age = 46 ± 14 years [mean ± SD], body mass index [BMI] = 27.2 ± 3.8 kg/m2) receiving continuous subcutaneous insulin infusion (CSII) therapy completed two 6-h conditions as follows: uninterrupted sitting (SIT) and sitting interrupted with 3-min bouts of simple resistance activities (SRAs) every 30 min. Basal and bolus insulin were standardized across conditions except in cases of hypoglycemia. Postprandial responses were assessed using incremental area-under-the-curve (iAUC) and total AUC (tAUC) from half-hourly venous sampling. Meal-based insulin sensitivity determined from glucose sensor and insulin pump (SiSP) was assessed from flash continuous glucose monitor and insulin pump data. Outcomes were analyzed using mixed models adjusted for sex, BMI, treatment order, and preprandial values. Results: Glucose iAUC did not differ by condition (SIT: 19.8 ± 3.0 [estimated marginal means ± standard error] vs. SRA: 14.4 ± 3.0 mmol.6 h.L-1; P = 0.086). Despite CSII being standardized between conditions, insulin iAUC was higher in SRA compared to SIT (137.1 ± 22.7 vs. 170.9 ± 22.7 mU.6 h.L-1; P < 0.001). This resulted in a lower glucose response relative to the change in plasma insulin in SRA (tAUCglu/tAUCins: 0.32 ± 0.02 vs. 0.40 ± 0.02 mmol.mU-1; P = 0.03). SiSP was also higher at dinner following the SRA condition, with no between-condition differences at breakfast or lunch. Conclusion: Regularly interrupting prolonged sitting in T1D may increase plasma insulin and improve insulin sensitivity when meals and CSII are standardized. Future studies should explore underlying mechanistic determinants and the applicability of findings to those on multiple daily injections. Trial Registration: Australian and New Zealand Clinical Trial Registry Identifier-ACTRN12618000126213 (www.anzctr.org.au).

Effect of Footwear Longitudinal Bending Stiffness on Energy Cost, Biomechanics, and Fatigue During a Treadmill Half-Marathon.

Introduction: Carbon plates have been used to increase running shoes' longitudinal bending stiffness (LBS), but their effect during a long duration run remains unknown. Our study aimed to identify the effect of LBS on energy cost of running (Cr), biomechanics, and fatigue during a half-marathon.Methods: Thirteen well-trained male runners (half-marathon time < 1 h40) performed two half-marathons at 95% of the running speed associated with their second ventilatory threshold on two separate visits, with either high-LBS shoes (HLBS, with carbon-plates) or standard-LBS (SLBS) shoes. Before and after the half-marathon, Cr at 12 km/h with both shoes (two 6-min bouts: Cr12) and ankle plantarflexors (PF) force were measured. During the half-marathon, running kinematics, shoe perceived comfort, and Cr were assessed.Results: During Cr12 measurements before and after the half-marathon, HLBS was 1.0 ± 2.1% more economical than SLBS (p < 0.001). During the half-marathon, Cr increased with running duration (p = 0.048) but there was no distance × condition effect. HLBS increased contact time (+3%, p = 0.01), decreased metatarsophalangeal joint dorsiflexion (-9%, p = 0.01), and was perceived less comfortable than SLBS, independently from running duration. At the end of the half-marathon, HLBS shoes led to higher PF force loss (-20.0 ± 9.8% vs -13.3 ± 11.0%, p = 0.048).Conclusions: Adding curved carbon plates in the running shoes slightly improved Cr during short running bouts at low intensity but not during a half-marathon. This discrepancy may be explained by day-to-day Cr variability and variation in shoe comfort. PF fatigue was higher with HLBS shoes but the accentuated fatigue did not further impact the biomechanical perturbations induced by the plates. Our results suggest that carbon plates alone do not provide a significant advantage for half-marathon performance.

Acute effect of resistive aquatic high-intensity interval training on metabolic costs in adults.

The effects of Aquatic High-Intensity Interval Training (AHIIT) and resistive AHIIT (Resistive AHIIT) to improve metabolic responses were not yet known. This study was to compare the metabolic responses and perceived effort in young healthy adults in a single session of AHIIT and resistive AHIIT. 20 healthy subjects (9 females, 11 males) performed a stationary running at a matched exercise intensity prior AHIIT and resistive AHIIT [10 × 1-min bouts of stationary running at 90% maximum heart rate (HR max) separated by 1-min active recovery] to examine the metabolic and cardiometabolic outcomes. Mixed effects models were applied to analyze the effects of group, time, and the interaction between group and time on both outcomes. The level of correlations between metabolic variables was checked by Pearson's linear correlation. There are significant differences on pre and post resting energy expenditure (REE) within both AHIIT and resistive AHIIT groups (p < 0.01) respectively as well as the subjective rate of perceived exertion (RPE) (p < 0.01) within RAHIIT group. A moderate correlation found on respiratory exertional ratio (RER) and RPE in resistive AHIIT (r = 0.534). No significant differences between groups in terms of HR max, mean heart rate (HR mean), peak oxygen consumption (VO2 peak) and total energy expenditure (TEE) (p = 0.50, p = 0.48, p = 0.81, p = 0.59). Resistive AHIIT provides comparable benefits of metabolic outcomes with AHIIT. Comparable results allowed AHIIT and resistive AHIIT prescriptions precisely.

A history of susceptibility to parasites and divergence in solitary, gregarious and agonistic behaviors of embiopterans.

Two species of Haploembia Ramburi (Oligotomidae: Embioptera), nonnative detritivores found in the western USA, display solitary tendencies, not typical for webspinners that usually share silk galleries. Reports from the 1960s based on native populations in Italy highlighted the impact of a gregarine that depressed male sterility and female survivorship in Haploembia solieri (Rambur). Sympatric asexual Haploembia tarsalis (Ross) lives a normal lifespan when parasitized, albeit suffering from reduced fecundity. Our goal is to characterize behavioral repertoires as individuals interact and to develop methods for future investigations focused on the impact of the little-known parasite. We quantified individual responses to conspecifics or other species in 10-min dyadic interactions and, in a 3-day trial, determined whether they aggregated when given dispersed resources. Replicated groups of four adult female H. solieri or H. tarsalis settled away from each other over the 3-day trials. In 10-min bouts of same or different species pairs, focal insects bolted back, retreated and attempted to escape when they encountered one another, especially when the opponent was H. tarsalis. Males courted conspecific females, but were dramatically repelled by H. tarsalis. Serving as a positive control, Oligotoma nigra (Hagen) (Oligotomidae) adult females paired with conspecifics displayed typical webspinner behaviors by sitting together, sharing silk. Haploembia solieri males did not respond negatively to O. nigra, not known to be parasitized by the gregarine, but did so when paired with H. tarsalis. Results align with the prediction that susceptibility to parasitism may have led to antisocial behaviors observed in two Haploembia species.

An alternate to accumulated oxygen deficit (AOD) for measuring anaerobic contribution: 'AOD_alt' is valid in normoxia and hypoxia.

The gold standard measure of anaerobic contribution is accumulated oxygen deficit (AOD). The purpose of this study was to investigate the validity of an alternate measure, AOD_alt. AOD_alt is the sum of the phosphocreatine and glycolytic contributions, which are estimated from post-exercise oxygen uptake and blood lactate concentration, respectively. In Study One, six women and three men performed 6-min bouts of heavy intensity cycle ergometer exercise, once in normoxia (FIO2 ~ 21%) and twice under hypoxic conditions (FIO2 ~ 15% and ~ 12%). In Study Two, four women and two men performed severe intensity tests to exhaustion, once in normoxia (~ 10min) and twice in hypoxia (FIO2 ~ 15% and ~ 10%). Physiological responses were measured during exercise and 7min of recovery. In 6min of heavy exercise, Study One, the alternate and criterion measures of anaerobic contribution (AOD_alt and AOD) were correlated, in normoxia and in hypoxia. In exhaustive severe exercise, Study Two, AOD_alt and AOD were correlated (r = 0.77) and similar, in normoxia and at FIO2 ~ 15%. However, AOD_alt and AOD values were neither correlated (r = 0.27) nor similar (57 ± 5mL·kg-1 vs 51 ± 7mL·kg-1) at FIO2 ~ 10%. These results confirm the validity of AOD_alt as a measure of anaerobic capacity in severe intensity exercise, demonstrate its validity in heavy exercise, and assert its validity in conditions of hypoxia (FIO2 ~ 12%).

Intensity Matters: Effect of Different Work-Matched Efforts on Subsequent Performance in Cyclists.

To assess the effect of 2 work-matched efforts of different intensities on subsequent performance in well-trained cyclists. The present study followed a randomized controlled crossover design. Twelve competitive junior cyclists volunteered to participate (age, 17 [1]y; maximum oxygen uptake, 71.0 [4.7]mL·kg-1·min-1). The power-duration relationship was assessed through 2-minute, 5-minute, and 12-minute field tests under fresh conditions (control). On subsequent days and following a randomized order, participants repeated the aforementioned tests after 2 training sessions matched for mechanical work (∼15kJ/kg) of different intensities (ie,a moderate-intensity continuous-training [60%-70% of critical power; CP] session or a session including high-intensity intervals [3-min repetition bouts at 110%-120% of the CP interspersed by 3-min rest periods]). A significantly lower power output was found in the 2-minute test after the high-intensity training session compared not only with the control condition (-8%, P < .001) but also with the moderate-intensity continuous-training session (-7%, P = .003), with no significant differences between the latter conditions. No significant differences between conditions were found for the remaining tests. As a consequence, the high-intensity training session resulted in significantly lower W' values compared to both the control condition (-27%, P = .001) and the moderate-intensity continuous-training session (-26%, P = .012), with no differences between the 2 latter conditions and with no differences for CP. A session including high-intensity intermittent efforts induces a greater fatigue, particularly in short-duration efforts and W', than a work-matched continuous-training session of moderate intensity.

Effect of cold beverages on whole-body heat exchange in young and older males during intermittent exercise in the heat.

To mitigate health risks associated with occupational heat stress, workers are advised to adhere to a work-rest regimen, and hydrate regularly. However, it remains unclear if beverage temperature influences whole-body heat exchange during work-rest cycles, and if responses differ in older workers who have a blunted heat loss capacity. Ten young (mean [SD]: 22 [3] years) and 10 older (60 [4] years) males performed four 15-min bouts of moderate-intensity cycling at a fixed rate of metabolic heat production (200 W·m-2), each interspersed by 15-min rest in dry heat (40°C, ~12% relative humidity). On separate days, participants consumed either ice-slurry (~0°C), standardized to provide a heat transfer capacity of 75 kJ·m-2, or an identical mass of warm fluid (37.5°C) before the first and third exercise bouts. Evaporative and dry heat exchange (direct calorimetry) and metabolic heat production (indirect calorimetry) were measured continuously to determine cumulative heat storage (summation of heat loss and heat gain) over the entire protocol. Rectal temperature was also measured continuously. Relative to warm fluid, ice-slurry ingestion reduced cumulative heat storage in young (69 [181] vs. 216 [94] kJ) and older males (90 [104] vs. 254 [140] kJ, main effect: p < 0.01), but was unaffected by age (p = 0.49). However, rectal temperature was unaffected by beverage temperature in both groups (all p ≥ 0.15). We show that cold fluid ingestion is an appropriate administrative control for both young and older males as it can mitigate increases in body heat content during moderate-intensity work-rest cycles in dry heat.

Correlation properties of heart rate variability for exercise prescription during prolonged running at constant speeds: A randomized cross-over trial.

The study explores the validity of the nonlinear index alpha 1 of detrended fluctuation analysis (DFAa1) of heart rate (HR) variability for exercise prescription in prolonged constant load running bouts of different intensities. 21 trained endurance athletes (9w and 12m) performed a ramp test for ventilatory threshold (vVT1 and vVT2) and DFAa1-based (vDFAa1-1 at 0.75 and vDFAa1-2 at 0.5) running speed detection as well as two 20-min running bouts at vDFAa1-1 and vDFAa1-2 (20-vDFAa1-1 and 20-vDFAa1-2), in which HR, oxygen consumption (VO2), respiratory frequency (RF), DFAa1, and blood lactate concentration [La-] were assessed. 20-vDFAa1-2 could not be finished by all participants (finisher group (FG), n=15 versus exhaustion group (EG), n=6). Despite similar mean external loads of vDFAa1-1 (10.6±1.9km/h) and vDFAa1-2 (13.1±2.4km/h) for all participants compared to vVT1 (10.8±1.7km/h) and vVT2 (13.2±1.9km/h), considerable differences were present for 20-vDFAa1-2 in EG (15.2±2.4km/h). 20-vDFAa1-1 and 20-DFAa1-2 yielded significant differences in FG for HR (76.2±5.7 vs. 86.4±5.9 %HRPEAK), VO2 (62.1±5.0 vs. 77.5±8.6 %VO2PEAK), RF (40.6±11.3 vs. 46.1±9.8bpm), DFA-a1 (0.86±0.23 vs. 0.60±0.15), and [La-] (1.41±0.45 vs. 3.34±2.24mmol/L). Regarding alterations during 20-vDFAa1-1, all parameters showed small changes for all participants, while during 20-vDFAa1-2 RF and DFAa1 showed substantial alterations in FG (RF: 15.6% and DFAa1: -12.8%) and more pronounced in EG (RF: 20.1% and DFAa1: -35.9%). DFAa1-based exercise prescription from incremental testing could be useful for most participants in prolonged running bouts, at least in the moderate to heavy intensity domain. In addition, an individually different increased risk of overloading may occur in the heavy to severe exercise domains and should be further elucidated in the light of durability and decoupling assessment.

Sex-dependent responses to acute sodium bicarbonate different dose treatment: A randomized double-blind crossover study

ObjectivesThis study quantified blood bicarbonate (HCO3−) kinetics and gastrointestinal upset to determine the gender-related ergogenic potential of sodium bicarbonate (0.15-, 0.25- and 0.35 gSB·kgFat-free mass (FFM)–1) in high intensity functional training. DesignDouble-blind randomized placebo-controlled crossover. MethodsThirty female and male athletes performed two bouts of the Wingate Anaerobic Test (WAnTPRE-HIFT and WAnTPOST-HIFT) interspaced with two 3-min bouts of Wall Balls and Burpees 120min after ingestion of three sodium bicarbonate doses. Blood HCO3− was determined pre-ingestion, after supplementation and before/post exercise. Gastrointestinal upset was evaluated 120min post-ingestion. Control (CTRL) measurements were performed. ResultsThere were significant gender×treatment interactions for: changes in blood HCO3− at 60min post-ingestion (p=0.014; η2p=0.104; at 0.15gSB·kgFFM−1 males experienced higher increase than females); peak power (p=0.015; η2p=0.103) and average power (p=0.005; η2p=0.124) during WAnTPOST-HIFT, and changes in peak power between the Wingate Anaerobic Test bouts (p=0.049; η2p=0.081). Sodium bicarbonate compared to PLA had no significant impact on Wall Balls and Burpees performance. The dose of 0.35gSB·kgFFM−1 resulted in higher less severe gastrointestinal symptoms compared to CTRL and 0.15gSB·kgFFM−1 (p=0.001; W=0.178); and higher total gastrointestinal upset compared to CTRL, PLA and 0.15gSB·kgFFM−1 (p<0.001; W=0.323). ConclusionsThere were dose- and gender-related differences in extracellular buffering capacity and ergogenic potential of sodium bicarbonate. The study suggested a detrimental impact of gastrointestinal upset on performance.

Assessment of Angular and Straight Linear Rowing Ergometers at Different Intensities of Exercise.

We aimed to conduct a biophysical comparison of angular (Biorower) and linear (Concept2) rowing ergometers across a wide spectrum of exercise intensities. Sixteen (eleven male) skilled rowers, aged 29.8 ± 8.6 and 23.6 ± 1.5 years, with international competitive experience, performed 7 × 3 min bouts with 30 W increments and 60 s intervals, plus 1 min of all-out rowing on both machines with 48 h in between. The ventilatory and kinematical variables were measured breath-by-breath using a telemetric portable gas analyzer and determined using a full-body markerless system, respectively. Similar values of oxygen uptake were observed between ergometers across all intensity domains (e.g., 60.36 ± 8.40 vs. 58.14 ± 7.55 mL/min/kg for the Biorower and Concept2 at severe intensity). The rowing rate was higher on the Biorower vs. Concept2 at heavy and severe intensities (27.88 ± 3.22 vs. 25.69 ± 1.99 and 30.63 ± 3.18 vs. 28.94 ± 2.29). Other differences in kinematics were observed across all intensity domains, particularly in the thorax angle at the finish (e.g., 19.44 ± 4.49 vs. 27.51 ± 7.59° for the Biorower compared to Concep2 at heavy intensity), likely due to closer alignment of the Biorower with an on-water rowing technique. The overall perceived effort was lower on the Biorower when compared to the Concept2 (14.38 ± 1.76 vs. 15.88 ± 1.88). Rowers presented similar cardiorespiratory function on both rowing ergometers, while important biomechanical differences were observed, possibly due to the Biorower's closer alignment with an on-water rowing technique.

Acute effects of exercise on gaze fixation and affective response inhibition in children with autism spectrum disorder: A randomized cross-over study.

Children with autism spectrum disorder (ASD) show impairments in response inhibition, especially in socio-emotional contexts. A single aerobic exercise session has the potential to temporarily reduce such impairments as findings from neurotypical children support acute benefits of this exercise type for inhibitory control and emotion recognition. In children with ASD, we therefore aimed to investigate the effects of an aerobic exercise bout on response inhibition in an emotional Go/NoGo task and gaze fixation as possible mechanism underlying changes in performance. Using a cross-over design, 29 patients completed a 20-min aerobic exercise bout at moderate intensity on a cycling ergometer and a control condition in a randomized order. An emotional Go/NoGo task was administered before and after both experimental conditions. Eye-tracking was performed during the cognitive task to assess the duration of gaze fixation of eyes and mouth parts of faces expressing happy or sad emotions. The results support no beneficial effect of exercise on performance on the emotional Go/NoGo task. Instead, patients showed a greater decrease in accuracy on Go trials displaying happy faces in the exercise compared to the control condition. This change was associated with a more pronounced decrease in the fixation duration of the eyes for faces expressing either happy or sad emotions. In conclusion, while a single session of moderately intense aerobic exercise does not affect response inhibition, it temporarily aggravates ASD-specific deficits in the processing of and response to facial emotions.

Cross-sectional associations of movement behaviour compositions with health-related quality of life in Australian children

ObjectivesTo examine associations of movement behaviour compositions with health-related quality of life in children. MethodsBaseline data (2018) from the TransformUs study were used. Overall, 891 children aged 7–12 years [69% of consented sample] recorded valid accelerometry data (ActiGraph GT3X+; 4 days, including ≥1 weekend day). Time spent sedentary, and in light-, moderate-, and vigorous-intensity physical activity were extracted. Health-related quality of life was assessed using five EQ-5D-Y health-related quality of life dimensions (mobility, looking after myself, doing usual activities, having pain/discomfort, and feeling worried/sad/unhappy [all dichotomized as no versus any problems]) and one continuous scale assessing overall perceived health. Regression models examined associations between waking movement behaviour compositions, including longer and shorter sedentary (<5 and ≥ 5 min) and physical activity (<1 and ≥ 1 min) bouts, and health-related quality of life. ResultsThe waking movement behaviour composition was associated with overall perceived health (whole sample, and boys and girls separately, but high socio-economic status only) and having pain/discomfort. More relative time in shorter versus longer sedentary bouts was associated with lower overall perceived health and higher odds of pain/discomfort. More relative time in shorter versus longer light-intensity and moderate-intensity bouts, were associated with decreased and increased odds of pain/discomfort, respectively. Finally, more time in shorter versus longer vigorous-intensity physical activity bouts was associated with better perceived health. ConclusionsChildren's movement behaviours seem to be related to health-related quality of life. Longitudinal evidence from more diverse samples with 24-h wear protocols and context-specific measures are needed to better understand this association.

Differential expression of genes in the RhoA/ROCK pathway in the hippocampus and cortex following intermittent hypoxia and high-intensity interval training.

Structural neuroplasticity such as neurite extension and dendritic spine dynamics is enhanced by brain-derived neurotrophic factor (BDNF) and impaired by types of inhibitory molecules that induce growth cone collapse and actin depolymerization, for example, myelin-associated inhibitors, chondroitin sulfate proteoglycans, and negative guidance molecules. These inhibitory molecules can activate RhoA/rho-associated coiled-coil containing protein kinase (ROCK) signaling (known to restrict structural plasticity). Intermittent hypoxia (IH) and high-intensity interval training (HIIT) are known to upregulate BDNF that is associated with improvements in learning and memory and greater functional recovery following neural insults. We investigated whether the RhoA/ROCK signaling pathway is also modulated by IH and HIIT in the hippocampus, cortex, and lumbar spinal cord of male Wistar rats. The gene expression of 25 RhoA/ROCK signaling pathway components was determined following IH, HIIT, or IH combined with HIIT (30 min/day, 5 days/wk, 6 wk). IH included 10 3-min bouts that alternated between hypoxia (15% O2) and normoxia. HIIT included 10 3-min bouts alternating between treadmill speeds of 50 cm·s-1 and 15 cm·s-1. In the hippocampus, IH and HIIT significantly downregulated Acan and NgR2 mRNA that are involved in the inhibition of neuroplasticity. However, IH and IH + HIIT significantly upregulated Lingo-1 and NgR3 in the cortex. This is the first time IH and HIIT have been linked to the modulation of plasticity-inhibiting pathways. These results provide a fundamental step toward elucidating the interplay between the neurotrophic and inhibitory mechanisms involved in experience-driven neural plasticity that will aid in optimizing physiological interventions for the treatment of cognitive decline or neurorehabilitation.NEW & NOTEWORTHY Intermittent hypoxia (IH) and high-intensity interval training (HIIT) enhance neuroplasticity and upregulate neurotrophic factors in the central nervous system (CNS). We provide evidence that IH and IH + HIIT also have the capacity to regulate genes involved in the RhoA/ROCK signaling pathway that is known to restrict structural plasticity in the CNS. This provides a new mechanistic insight into how these interventions may enhance hippocampal-related plasticity and facilitate learning, memory, and neuroregeneration.

Are anti-gravity treadmills reliable to explore exercise energy metabolism at low degrees of alleviation in normal-weight male individuals?

Exploring the independent effect of mechanical discharge in response to weight loss (WL) seems necessary but remains highly challenging from a methodological point. Anti-gravity treadmills could be relevant to simulate a mechanical WL by body weight support (BWS), but their reliability remains unclear to properly explore exercise energy metabolism, especially at low degrees of alleviations. The study aimed to evaluate the accuracy and reproducibility of an anti-gravity treadmill to generate BWS, and the reproducibility of cardiometabolic responses to an exercise performed at low degrees of BWS on this device. Observed BWS of 18 normal-weight males was obtained twice at seven degrees of target BWS (i.e., 0, 3, 6, 9, 12, 15, 18%) using a digital scale inside the anti-gravity treadmill, and was compared to the expected BWS. Then, 15 of them performed 5-min bout of low-intensity walking exercise at these degrees of BWS in a randomized order, separated by 4-min rest. The exercise was identically repeated on three occasions separated by a minimum of 3 days. Energy metabolism and heart rate (HR) were measured throughout the exercise by indirect calorimetry and a HR monitor, respectively. The observed BWS were significantly different from the expected BWS (p< 0.001), and there was a high inter- and intra-individual variability in BWS generated by the anti-gravity treadmill. Results showed an overall good reliability of VO2 (intraclass correlation coefficients (ICC) values ranging from 0.67 to 0.85) and HR (ICC > 0.8) in response to exercise. An effect of the degree of BWS was observed for VO2 (p< 0.001), illustrating reduced values at 15% and 18% of BWS compared to 0, 3, and 6%. Such device might not be adapted to simulate low degrees of WL in normal-weight males, particularly when it comes to the exploration of energy metabolism.

Associations between accelerometer-measured physical activity and sedentary behaviour with physical function among older women: a cross-sectional study

BackgroundThis study aimed to investigate the relationships between accelerometer-measured physical activity (PA) and sedentary behaviour (SB) with physical function (PF) among older Chinese women in the community.MethodsThe present study comprised 1,113 community-dwelling older females, with an average age of 65 ± 2 years. We employed a linear regression analysis to investigate the relationship between patterns of PA and SB with PF. PA variables consisted of total PA time, bouted PA time (a continuous PA that lasts equal to or more than 10 min), and sporadic PA time (a continuous PA that lasts less than 10 min). SB variables included total SB time, 30-min bout of SB (a continuous SB that lasts equal to or more than 30 min), and 60-min bout of SB (a continuous SB that lasts equal to or more than 60 min). PF variables comprised handgrip strength (HGS), one-legged stance test with eyes closed (OLSTEC), usual walking speed (UWS), maximum walking speed (MWS) and chair-stand time (CT). To explore the joint effects of moderate-to-vigorous-intensity PA (MVPA) and SB on PF, we divided the duration of SB and MVPA participation in older women into different combinations: low MVPA & high SB, low MVPA & low SB, high MVPA & high SB, high MVPA & low SB.ResultsThe study revealed a significant association between 30-min bout of SB and CT, which remained after adjusting for total MVPA time (P = 0.021). Both total MVPA and bouted MVPA were found to be positively associated with better UWS, MWS, CT, and PF Z-score. When the combination of low MVPA & high SB was used as a reference, the regression coefficients for PF ascended by 1.32 (P < 0.001) in the high MVPA & high SB group and by 1.13 (P < 0.001) in the high MVPA & low SB group.ConclusionsA significant association was observed between poorer lower limb function and prolonged, uninterrupted SB in older women, rather than with the total SB time. Concurrently, the insufficient engagement in MVPA may also be a crucial factor contributing to poorer PF in older women. Engaging in longer durations and higher intensity of PA, such as bouts of MVPA lasting a minimum of 10 min or longer, may contribute to better PF.

Take a Break for Memory Sake! Effects of Short Physical Activity Breaks on Inhibitory Control, Episodic Memory, and Event-Related Potentials in Children.

The pervasive sedentary lifestyle exacerbated by the COVID-19 pandemic has significantly reduced physical activity (PA) among school-age children, necessitating innovative strategies to evaluate short PA breaks that are feasible in a classroom setting. This study explored the cognitive and neurophysiological (electroencephalography; EEG) impacts of short bouts of different PA modalities on inhibitory control (flanker task) and episodic memory (word recognition task) in children. Utilizing a within-participants cross-over design, thirty-six children (n = 36; 9-12 years old) attended the lab on three separate days with each visit including either a 9 min bout of sustained moderate-intensity cycling, high-intensity interval exercise (HIIE), or seated rest. Event-related potentials (ERPs) were assessed during the flanker task (P3 component) and the word recognition task (LPC and FN400 components) to elucidate the neural mechanisms underpinning behavioral outcomes. Findings indicated no differences in flanker performance but greater episodic memory recall for HIIE compared to seated rest. Neurophysiological results revealed no differences for P3, but notably larger amplitude for LPC and FN400 postcycling, particularly over parietal electrode sites. These results underscore the potential of short PA breaks to improve cognitive and neurocognitive function in children, offering a feasible integration strategy into daily school routines without extensive time commitment.

Aquatic High-Intensity Interval Deep Water Running Influence on Cardiometabolic Health and Cognitive Psychological Responses in Women.

To investigate the effects of an 8-wk AHIIT-DWR intervention compared with land-based HIT training (LHIIT) on cardiometabolic health, cognitive, and psychological outcomes in inactive elderly women. Seventy inactive elderly women aged 60 yr or above were randomly assigned into two groups: AHIIT-DWR and LHIIT. The AHIIT-DWR group engaged in DWR sessions comprising 30 min of interval training, consisting of ten 2-min exercise bouts at 80%-90% of their maximal heart rate (HR max ), with 1-min active recovery at 70% HR max between bouts, for two sessions per week, for 8 wk. The LHIIT group performed treadmill running at the same intensity. Both groups showed similar cardiovascular fitness, maximal aerobic capacity (V̇O 2max ), HR max , and RER improvement ( P > 0.05), whereas AHIIT-DWR showed a significant improvement in aerobic capacity minute ventilation (V̇E), metabolic equivalents (METs), and O 2 pulse ( P < 0.05) over the 8-wk intervention. Both AHIIT-DWR and LHIIT significantly decreased triglycerides, total cholesterol, HDL, and LDL postintervention ( P < 0.05). No significant group differences were observed for cognitive function assessed by MMSE and MOCA ( P > 0.05). Both groups showed similar enjoyment levels, self-efficacy scores, and high adherence rates (>90%). Our study suggests that AHIIT-DWR can elicit a similar improvement in cardiorespiratory health, metabolic blood markers, cognitive function assessed by MMSE and MOCA, and psychological responses as LHIIT in inactive elderly women.

The Characteristics of Endurance Events with a Variable Pacing Profile-Time to Embrace the Concept of "Intermittent Endurance Events"?

A variable pacing profile is common in different endurance events. In these races, several factors, such as changes in elevation or race dynamics, lead participants to perform numerous surges in intensity. These surges are so frequent that certain events, such as cross-country (XC) skiing, mountain biking (MTB), triathlon, and road cycling, have been termed "intermittent endurance events". The characteristics of these surges vary depending on the sport: MTB and triathlon require athletes to perform numerous short (<10 s) bouts; XC skiing require periods of short- and moderate-(30 s to 2 min) duration efforts, while road cycling is comprised of a mix of short-, moderate-, and long-duration (>2 min) bouts. These bouts occur at intensities above the maximal metabolic steady state (MMSS), with many efforts performed at intensities above the athletes' maximal aerobic power or speed (MAP/MAS) (i.e., supramaximal intensities). Given the factors that influence the requirement to perform surges in these events, athletes must be prepared to always engage in a race with a highly stochastic pace. The aim of this review is to characterize the variable pacing profile seen in endurance events and to discuss how the performance of multiple maximal and supramaximal surges in intensity can affect how athletes fatigue during a race and influence training strategies that can lead to success in these races.