Bouts Of Activity Research Articles

Hip and Groin Injury Prevention in Elite Athletes and Team Sport – Current Challenges and Opportunities

Hip and groin injury (HAGI) has been reported as a source of significant time loss in elite sport. Field and court-based sports such as basketball, football, hockey, soccer, among others, require explosive multiplanar movement in single stance and high-speed change of direction. Often situations arise where sub-optimal pre-season training has occurred or congested in-season competition minimizes physiologic recovery periods between bouts of physical activity, both of which could magnify concomitant existing risk factors and increase injury risk. Identification and management of HAGI can be challenging as numerous structures within the region can be drivers of pain and injury, especially when considering the likelihood of concurrent pathology and injury reoccurrence. Focused prevention strategies have been suggested, but their practical clinical implementation has not been heavily investigated across the sporting spectrum. The purpose of this commentary is to review the historical and current state of HAGI, while focusing on applying evidence and clinical experience towards the development of future risk reduction strategies.Level of evidence: 5

Physiology of Basketball - Field Tests. Review Article.

The game of basketball is characterized by short and intense bouts of activity at medium to high frequency. Basketball entails specific types of movements, physiological requirements and energy sources. The duration of physiological responses involving ATP, CP and glycolysis responses to this type of activity is 5-6 seconds for a single sprint, and a contribution of the aerobic system is of less than 10%. Recovery periods in basketball, as a rule, are not long enough to fill the gap for such high intensity activities. It is hard to achieve the same level of performance consistently over time in repeated sprints. This means that basketball players need great athletic ability in order to demonstrate speed, strength and power required to produce a successful performance most proficiently. Therefore, tests are needed to help coaches to monitor their players and ensure that they have the physiological capacity required for the game. The aim of fitness tests is to assess the condition of athletes in terms of each fitness component, in order to determine what needs to be improved through the training program and to conduct retests at set times to assess whether their condition has changed. The literature offers a number of widely used tests to measure aerobic and anaerobic fitness. This article reviews the physiological demands of basketball and analyzes the field tests commonly used at present. The article emphasizes the need for a specific test that will serve coaches and physical fitness trainers in monitoring their players.

An Anticipatory Circuit Modification That Modifies Subsequent Task Switching.

Modulators are generally expected to establish a network configuration that is appropriate for the current circumstances. We characterize a situation where the opposite is apparently observed. A network effect of a peptide modulator is counterproductive in that it tends to impede rather than promote the creation of the configuration that is appropriate when the modulator is released. This raises a question: why does release occur? We present data that strongly suggest that it impacts task switching. Our experiments were conducted in an Aplysia feeding network that generates egestive and ingestive motor programs. Initial experiments focused on egestive activity and the neuron B8. As activity becomes egestive, there is an increase in synaptic drive to B8 and its firing frequency increases (Wang et al., 2019). We show that, as this occurs, there is also a persistent current that develops in B8 that is outward rather than inward. Dynamic clamp introduction of this current decreases excitability. When there is an egestive-ingestive task switch in Aplysia, negative biasing is observed (i.e., a bout of egestive activity has a negative impact on a subsequent attempt to initiate an ingestive response) (Proekt et al., 2004). Using an in vitro analog of negative biasing, we demonstrate that the outward current that develops during egestive priming plays an important role in establishing this phenomenon. Our data suggest that, although the outward current induced as activity becomes egestive is counterproductive at the time, it plays an anticipatory role in that it subsequently impacts task switching.SIGNIFICANCE STATEMENT In this study, we identify a peptide-induced circuit modification (induction of an outward current) that does not immediately promote the establishment of a behaviorally appropriate network configuration. We ask why this might occur, and present data that strongly suggest that it plays an important role during task switching. Specifically, our data suggest that the outward current we characterize plays a role in the negative biasing that is seen in the mollusc Aplysia when there is a transition from egestive to ingestive activity. It is possible that the mechanism that we describe operates in other species. A negative effect of egestion on subsequent ingestion is observed throughout the animal kingdom.

A comparison of moist heat, dry heat, chemical dry heat and icy hot for deep tissue heating and changes in tissue blood flow.

Background: Intermittent bouts of heavy activity at greater than normal exercise intensity can cause delayed onset muscle soreness (DOMS). Several products are commercially available, all alleging to reduce DOMS. In the present investigation, 40 subjects (average age 27.0+/-4.4 years, average BMI 26.8) were assessed to determine the effect of 4 of these products on skin and muscle temperature and blood flow during 2 hours of application. These included ThermaCare Dry Heat Wraps, ThermaCare Moist Heat Wraps, Icy Hot Patches, and hydrocollator heat packs. Methods; Blood flow was measured (by laser doppler flow meter) over and in the quadriceps muscle and tissue temperature was measured (by thermistors and thermocouples) in these same areas. Results: The results of the study indicated that only ThermaCare Dry and Moist Heat Wraps both heated the muscle and increased muscle blood flow. The menthol and methyl salicylate compounds in Icy Hot cooled muscle. Skin blood flow increased 300% after the moist heat was applied after 45 minutes, low level continuous dry heat almost 256% but it took 105 minutes to reach this flow, hydrocollator heat wraps increased by 201% but only for only first 45 minutes and then back to baseline, a slight reduction in skin blood flow was seen with Icy Hot gel applied to the skin. Moist heat caused muscle temperature to increase by an average of 3.1 Deg C. Dry heat caused muscle temperature to increase by 2.2 Deg C, while hydrocollator packs increased temperature by 0.4 Deg C. Icy hot had no effect on muscle temperature. Conclusion: Continuous low level heat products had better penetration into muscle and increased blood flow the best compared to hydrocollator heat packs and Icy Hot patches.

The chronic effect of physical activity on postprandial triglycerides in postmenopausal women: A randomized controlled study

Background/ObjectiveThis study examined the chronic effect of increased physical activity on postprandial triglycerides in older women. MethodsTwenty-six women, aged 72 ± 5 years (mean ± SD), participated in this study. Participants in the physical activity group (n = 11) were asked to increase their activities above their usual lifestyle levels for 12 weeks. Participants in the control group (n = 15) maintained their usual lifestyle for 12 weeks. All participants rested and consumed a standardized breakfast after a 24-h period of physical activity avoidance at baseline, 4 weeks, and 12 weeks. Blood samples were collected in the fasted state (0 h) and at 2, 4, and 6 h after breakfast. ResultsThe average increased time spent in self-selected activities per day was 1.1 ± 19.3 min over the 12 weeks compared with the baseline in the physical activity group. There was no difference in the postprandial time-averaged triglyceride area under the curve at baseline (1.59 ± 0.81 vs. 1.39 ± 0.67 mmol/L, p = 0.515) or over the 12-week intervention (1.78 ± 1.00 vs. 1.31 ± 0.67 mmol/L, p = 0.212) between the physical activity and control groups. ConclusionPostprandial triglyceride concentrations were not reduced after performing self-selected activities under free-living conditions in older women when these responses were determined 24 h after the last physical activity bout. (Trial registration ID: UMIN000037420).

Is replacing sedentary time with bouts of physical activity associated with inflammatory biomarkers in children?

This study aimed to investigate the theoretical impact of reallocating a specific amount of sedentary time with an equal amount of (a) total and (b) ≥1-minute bout-accumulated time spent in different activity intensities, on inflammatory biomarkers in 8- to 9-year-old children. Accelerometry and inflammatory biomarker baseline data from the Transform-Us! Study (complete cases n=149) were utilized. Isotemporal linear models with the Gaussian distribution and identity link functions were used to assess associations between the activity replacements and seven individual inflammatory biomarkers, including C-reactive protein (CRP), and Interleukin (IL)-2, IL-6, IL-8, and IL-10, as well as combined inflammatory and pro-inflammatory composite scores. Eighty-five percent of children met physical activity recommendations. Replacing 10minutes of sedentary time per day with VPA, regardless of how this was accumulated, was beneficially associated with CRP and both combined composite scores. In contrast, replacing 10min/day of sedentary time with≥1-minute MPA bouts was detrimentally associated with CRP and the inflammatory composite score. Substitutions with other activity intensities were not significantly associated with any individual inflammatory biomarkers, or combined inflammatory and pro-inflammatory composite scores. In healthy and active school-aged children, evidence of the theoretical impact of replacing sedentary time with physical activity, regardless of intensity or accumulation, on markers of systemic inflammation was limited. Longitudinal research is needed to investigate the long-term impacts of reallocating sedentary time with physical activity, and particularly VPA, for inflammatory biomarkers in children, including those with increased risk of inflammation.

NREM sleep stages specifically alter dynamical integration of large-scale brain networks.

SummaryFunctional dissociations in the brain observed during non-rapid eye movement (NREM) sleep have been associated with reduced information integration and impaired consciousness that accompany increasing sleep depth. Here, we explored the dynamical properties of large-scale functional brain networks derived from transient brain activity using functional magnetic resonance imaging. Spatial brain maps generally display significant modifications in terms of their tendency to occur across wakefulness and NREM sleep. Unexpectedly, almost all networks predominated in activity during NREM stage 2 before an abrupt loss of activity is observed in NREM stage 3. Yet, functional connectivity and mutual dependencies between these networks progressively broke down with increasing sleep depth. Thus, the efficiency of information transfer during NREM stage 2 is low despite the high attempt to communicate. Critically, our approach provides relevant data for evaluating functional brain network integrity and our findings robustly support a significant advance in our neural models of human sleep and consciousness.

Intensity of daily physical activity – a key component for improving physical capacity after minor stroke?

Purpose Elucidating the complex interactions between physical activity (PA), a multidimensional concept, and physical capacity (PC) may reveal ways to improve rehabilitation interventions. This cross-sectional study aimed to explore which PA dimensions are related to PC in people after minor stroke. Materials and methods Community dwelling individuals >6 months after minor stroke were evaluated with a 10-Meter-Walking-Test (10MWT), Timed-Up & Go, and the Mini Balance Evaluation System Test. The following PA outcomes were measured with an Activ8 accelerometer: counts per minute during walking (CPMwalking; a measure of intensity), number of active bouts (frequency), mean length of active bouts (distribution), and percentage of waking hours in upright positions (duration). Multivariable linear regression models, adjusted for age, sex and BMI, were used to assess the relationships between PC and PA outcomes. Results Sixty-nine participants [62.2 ± 9.8 years, 61% male, 20 months post onset (IQR 13.0–53.5)] were included in the analysis. CPMwalking was significantly associated to PC in the 10MWT (std. ß = 0.409, p = 0.002), whereas other associations between PA and PC were not significant. Conclusions The PA dimension intensity of walking is significantly associated with PC, and appears to be an important tool for future interventions in rehabilitation after minor stroke. Implications for rehabilitation It is recommended to express physical activity after minor stroke in multiple dimensions such as intensity, frequency, duration and distribution. In particular, intensity of physical activity measured with accelerometer counts is most closely related to physical capacity. The findings of this study underline the importance of being physically active beyond a certain intensity. In future development of interventions and guidelines that aim to promote daily physical activity, intensity should be taken into account.

Effects of interrupting sitting with different activity bouts on postprandial lipemia: A randomized crossover trial.

To determine whether interrupting prolonged sitting with three different activity breaks has both acute and chronic effects on postprandial lipid metabolism immediately after the activity-break period and on the following day, this study is a secondary analysis of an experimental research, which included 16 sedentary healthy adults (7 men, 24±3years, BMI 22.2±2.3kg/m2 ) who completed four 26-h laboratory trials. Participants spent 22.5hours in a whole room calorimeter for testing energy expenditure (EE), including a 9-h activity-break period: (a) 9-h prolonged sitting (SIT); (b) 3minutes of brisk walking (60% VO2max ) in between every 30-min sitting bout (WALK3), (c) 5minutes every 45-min (WALK5), and (d) 8minutes every 60-min (WALK8). Total area under the curve (tAUC) and incremental AUC (iAUC) for 2-h postprandial serum triglyceride (TG) levels and non-esterified fatty acid (NEFA) levels were examined immediately after the 9-h trial (post-dinner) and the next morning (post-breakfast). WALK8 reduced the post-breakfast TG tAUC by 11% (P=.041) relative to SIT, and the effect was attenuated after adjustment for EE. The tAUC and iAUC indicated no significant treatment effects on post-dinner TG and NEFA, and post-breakfast NEFA in any of the activity-break trials. EE was positively associated with the post-breakfast NEFA iAUC (unstandardized β=0.17µmol/L/MJ [0.05-0.28], P=.006). There was a chronic effect of interrupting sitting with short bouts (8minutes) of brisk walking every 60minutes on postprandial lipemia the following morning after intervention, and higher activity bout-induced EE may be more effective in sedentary, healthy adults.

Physical Activity as a Predictor of Chronic Pain Following Pediatric Spinal Surgery.

(1) Characterize objective physical activity patterns via actigraphy over 4 months postspinal fusion surgery, and (2) examine associations between activity patterns at 2-week and chronic postsurgical pain (CPSP) status at 4 months. Data from 109 youth (10 to 18 y) who underwent spinal fusion surgery at a children's hospital in the Northwestern United States were analyzed. Youth completed questionnaires and actigraphic assessment of physical activity presurgery, and 2 weeks and 4 months postsurgery. Eighteen percent of youth developed CPSP at 4 months. Presurgery physical activity was similar for youth with and without CPSP. At 2 weeks postsurgery, daily activity levels were lower for youth who developed CPSP as compared with those who did not, including lower mean activity (168 vs. 212 counts/min, P=0.01), fewer activity bouts (n=1.7 vs. 2.6, P=0.02), and shorter bout duration (27 vs. 40 min, P=0.02). Differences in activity were maintained at 4 months such that youth with CPSP had lower mean activity (284 vs. 334 counts/min, P=0.03), as well as greater proportion time spent sedentary and lower proportion time in light activity than youth without CPSP. In adjusted models examining 2-week actigraphy as a predictor of 4-month pain status, mean activity (odds ratio=0.99, P=0.04) and number of activity bouts (odds ratio=0.79, P=0.02) were associated with subsequent CPSP status over and above 2-week pain intensity. Lower activity engagement during the initial weeks following spinal fusion surgery was associated with development of CPSP, suggesting early physical activity limitations as a risk factor for CPSP in youth. Understanding recovery patterns is critical for identifying those at risk for chronic pain and implementing early interventions.

Adherence to physical activity and cardiovascular recommendations during the 2years after stroke rehabilitation discharge.

Objective measurement is essential to represent habitual physical activity. To date only one study has objectively measured physical activity for>12months after stroke. This study aimed to measure physical activity, cardiovascular risk factors, mobility, mood, fatigue and cognition during the 2years after rehabilitation discharge and to investigate whether stroke survivors meet physical activity and cardiovascular risk recommendations. This was a longitudinal observational study. Survivors of a first-ever stroke admitted to a large metropolitan rehabilitation hospital were recruited. Outcomes were measured at rehabilitation discharge and 6, 12 and 24months later. Outcomes were physical activity measured by the SenseWear Armband (e.g., moderate-vigorous physical activity, steps/day) and cardiovascular risk factors (e.g., blood pressure, fasting lipid profile and plasma glucose, waist circumference, body mass index), mobility, mood, fatigue and cognition. Changes over time were evaluated with random-effects regression modelling. Participants (n=79, 33% female) had mean (SD) age of 65 (14) years and median gait speed 1.2m/s (interquartile range: 0.8-1.4) at baseline. We found no change in physical activity levels over time. Step count and time spent in bouts of moderate-vigorous physical activity remained low. Many participants achieved the recommended 30min of daily moderate-vigorous physical activity at baseline, but this was decreased at 2years (72% [57/79] versus 65% [37/57]). Adherence to cardiovascular recommendations decreased over time, notably for body mass index, plasma glucose and triglyceride levels. Waist circumference and body mass index increased at each time point relative to baseline (by a mean of 3.2cm and 1.2kg.m2, respectively, at 2years, P<0.01). This is the largest longitudinal study of objectively measured physical activity after stroke. Adherence to cardiovascular risk recommendations decreased over time post-stroke, and physical activity levels remained low. Stroke survivors may benefit from annual multidisciplinary reviews to identify increasing risk and initiate appropriate interventions.

Advanced analytical methods to assess physical activity behaviour using accelerometer raw time series data: a protocol for a scoping review

BackgroundPhysical activity (PA) is a complex multidimensional human behaviour. Currently, there is no standardised approach for measuring PA using wearable accelerometers in health research. The total volume of PA is an important variable because it includes the frequency, intensity and duration of activity bouts, but it reduces them down to a single summary variable. Therefore, analytical approaches using accelerometer raw time series data taking into account the way PA are accumulated over time may provide more clinically relevant features of physical behaviour. Advances on these fields are highly needed in the context of the rapid development of digital health studies using connected trackers and smartwatches. The objective of this review will be to map advanced analytical approaches and their multidimensional summary variables used to provide a comprehensive picture of PA behaviour.MethodsThis scoping review will be guided by the Arksey and O’Malley methodological framework. A search for relevant publications will be undertaken in MEDLINE (PubMed), Embase and Web of Science databases. The selection of articles will be limited to studies published in English from January 2010 onwards. Studies including analytical methods that go beyond total PA volume, average daily acceleration and the conventional cut-point approaches, involving tri-axial accelerometer data will be included. Two reviewers will independently screen all citations, full-text articles and extract data. The data will be collated, stored and charted to provide a descriptive summary of the analytical methods and outputs, their strengths and limitations and their association with different health outcomes.DiscussionThis protocol describes a systematic method to identify, map and synthesise advanced analytical approaches and their multidimensional summary variables used to investigate PA behaviour and identify potentially clinically relevant features. The results of this review will be useful to guide future research related to analysing PA patterns, investigate their association with health conditions and suggest appropriate recommendations for changes in PA behaviour. The results may be of interest to sports scientists, clinical researchers, epidemiologists and smartphone application developers in the field of PA assessment.Scoping review registrationThis protocol has been registered with the Open Science Framework (OSF): https://osf.io/yxgmb.

Adding web-based behavioural support to exercise referral schemes for inactive adults with chronic health conditions: the e-coachER RCT.

There is modest evidence that exercise referral schemes increase physical activity in inactive individuals with chronic health conditions. There is a need to identify additional ways to improve the effects of exercise referral schemes on long-term physical activity. To determine if adding the e-coachER intervention to exercise referral schemes is more clinically effective and cost-effective in increasing physical activity after 1 year than usual exercise referral schemes. A pragmatic, multicentre, two-arm randomised controlled trial, with a mixed-methods process evaluation and health economic analysis. Participants were allocated in a 1 : 1 ratio to either exercise referral schemes plus e-coachER (intervention) or exercise referral schemes alone (control). Patients were referred to exercise referral schemes in Plymouth, Birmingham and Glasgow. There were 450 participants aged 16-74 years, with a body mass index of 30-40 kg/m2, with hypertension, prediabetes, type 2 diabetes, lower limb osteoarthritis or a current/recent history of treatment for depression, who were also inactive, contactable via e-mail and internet users. e-coachER was designed to augment exercise referral schemes. Participants received a pedometer and fridge magnet with physical activity recording sheets, and a user guide to access the web-based support in the form of seven 'steps to health'. e-coachER aimed to build the use of behavioural skills (e.g. self-monitoring) while strengthening favourable beliefs in the importance of physical activity, competence, autonomy in physical activity choices and relatedness. All participants were referred to a standard exercise referral scheme. Minutes of moderate and vigorous physical activity in ≥ 10-minute bouts measured by an accelerometer over 1 week at 12 months, worn ≥ 16 hours per day for ≥ 4 days including ≥ 1 weekend day. Other accelerometer-derived physical activity measures, self-reported physical activity, exercise referral scheme attendance and EuroQol-5 Dimensions, five-level version, and Hospital Anxiety and Depression Scale scores were collected at 4 and 12 months post randomisation. Participants had a mean body mass index of 32.6 (standard deviation) 4.4 kg/m2, were referred primarily for weight loss and were mostly confident self-rated information technology users. Primary outcome analysis involving those with usable data showed a weak indicative effect in favour of the intervention group (n = 108) compared with the control group (n = 124); 11.8 weekly minutes of moderate and vigorous physical activity (95% confidence interval -2.1 to 26.0 minutes; p = 0.10). Sixty-four per cent of intervention participants logged on at least once; they gave generally positive feedback on the web-based support. The intervention had no effect on other physical activity outcomes, exercise referral scheme attendance (78% in the control group vs. 75% in the intervention group) or EuroQol-5 Dimensions, five-level version, or Hospital Anxiety and Depression Scale scores, but did enhance a number of process outcomes (i.e. confidence, importance and competence) compared with the control group at 4 months, but not at 12 months. At 12 months, the intervention group incurred an additional mean cost of £439 (95% confidence interval -£182 to £1060) compared with the control group, but generated more quality-adjusted life-years (mean 0.026, 95% confidence interval 0.013 to 0.040), with an incremental cost-effectiveness ratio of an additional £16,885 per quality-adjusted life-year. A significant proportion (46%) of participants were not included in the primary analysis because of study withdrawal and insufficient device wear-time, so the results must be interpreted with caution. The regression model fit for the primary outcome was poor because of the considerable proportion of participants [142/243 (58%)] who recorded no instances of ≥ 10-minute bouts of moderate and vigorous physical activity at 12 months post randomisation. The design and rigorous evaluation of cost-effective and scalable ways to increase exercise referral scheme uptake and maintenance of moderate and vigorous physical activity are needed among patients with chronic conditions. Adding e-coachER to usual exercise referral schemes had only a weak indicative effect on long-term rigorously defined, objectively assessed moderate and vigorous physical activity. The provision of the e-coachER support package led to an additional cost and has a 63% probability of being cost-effective based on the UK threshold of £30,000 per quality-adjusted life-year. The intervention did improve some process outcomes as specified in our logic model. Current Controlled Trials ISRCTN15644451. This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 63. See the NIHR Journals Library website for further project information.

Physical Exertion Diminishes Static and Dynamic Balance in Firefighters

Half of all work-related injuries in the fire service are musculoskeletal-based due to slips, trips, and overexertion. This study evaluated the effects of physical exertion on balance in firefighters. Forty-one firefighters completed a physical exertion protocol with static and dynamic balance assessments while in personal protective equipment. Following the physical exertion protocol, we identified a significant decrease in anterior reach of the right limb, and significant increases in rectangular displacement area in both double- and single-legged stances. Balance is diminished in firefighters wearing personal protective equipment after engaging in a short bout of physical activity, suggesting a potential risk factor for lower extremity injury in the fire service.

Untapping the Health Enhancing Potential of Vigorous Intermittent Lifestyle Physical Activity (VILPA): Rationale, Scoping Review, and a 4-Pillar Research Framework

Recently revised public health guidelines acknowledge the health benefits of regular intermittent bouts of vigorous intensity incidental physical activity done as part of daily living, such as carrying shopping bags, walking uphill, and stair climbing. Despite this recognition and the advantages such lifestyle physical activity has over continuous vigorous intensity structured exercise, a scoping review we conducted revealed that current research in this area is, at best, rudimentary. Key gaps include the absence of an empirically-derived dose specification (e.g., minimum duration of lifestyle physical activity required to achieve absolute or relative vigorous intensity), lack of acceptable measurement standards, limited understanding of acute and chronic (adaptive) effects of intermittent vigorous bouts on health, and paucity of essential information necessary to develop feasible and scalable interventions (e.g., acceptability of this kind of physical activity by the public). To encourage collaboration and research agenda alignment among groups interested in this field, we propose a research framework to further understanding of vigorous intermittent lifestyle physical activity (VILPA). This framework comprises four pillars aimed at the development of: (a) an empirical definition of VILPA, (b) methods to reliably and accurately measure VILPA, (c) approaches to examine the short and long-term dose–response effects of VILPA, and (d) scalable and acceptable behavioural VILPA-promoting interventions.Graphic

Short Bouts of Physical Activity Are Associated with Reduced Smoking Withdrawal Symptoms, but Perceptions of Intensity May Be the Key.

The primary aim of this study was to assess the effectiveness of a short bout (10 min) of moderate-intensity exercise to reduce withdrawal symptomatology, craving and negative affect; while the secondary aim was to assess how the effectiveness of a short bout of moderate exercise can be modulated by the perception of intensity in physically active and low-activity smokers. Fifty low-activity and physically active smokers were recruited (24 male and 26 female) and randomized in three different conditions. Prescribed (objective) moderate intensity (OBJ) and perceived moderate intensity (PER), and passive waiting (PW). After the intervention (T3), smokers reported less desire to smoke in the PER (p < 0.001) and OBJ (p < 0.001) conditions, relative to the PW condition. At T3 smokers in the PER condition reported less negative affect than smokers in the PW condition relative to the baseline (T1) (p < 0.007). Further, smokers in the PER condition reported less negative affect than smokers in the PW condition (p < 0.048). Physically active (PA) smokers perceived less exertion than low-activity (LA) smokers, and the effects were stronger in the PER condition relative to OBJ. Generally, our results suggest that a short bout of moderate exercise helps both LA and PA smokers. These findings provided a novel insight into the psychological mechanisms that affect the efficacy of the exercise in smoking cessation and suggest that exercise should be tailored according to individual perception of intensity.

Reallocating sedentary time with total physical activity and physical activity bouts in children: Associations with cardiometabolic biomarkers

ABSTRACT This cross-sectional study examined theoretical effects of reallocating sedentary time (SED) with total physical activity, and physical activity bouts of varying intensities, on children’s cardiometabolic biomarkers. Baseline data from the Transform-Us! trial (Melbourne, Australia) was used. Participant data were included if accelerometer and blood biomarker data were complete (n = 169; 8.7 [0.4] years; 56% girls). Isotemporal substitution models assessed the impact of replacing 10 minutes of SED with 10 minutes of total physical activity or physical activity in bouts of varying intensities on cardiometabolic biomarkers. In adjusted models, replacing 10 minutes of SED with vigorous-intensity physical activity (VPA) was associated with lower triglycerides in the whole sample. Replacing SED with VPA was associated with better high-density lipoprotein cholesterol (HDL-C) and triglycerides in children with healthy weight. Replacing SED with MPA was associated with better homoeostatic model assessment of insulin resistance (HOMA-IR) and HDL-C, in children with healthy weight and overweight, respectively. Substituting SED with VPA specifically accumulated in ≥1-min bouts was detrimentally associated with HOMA-IR in children with healthy weight but beneficially with the cardiometabolic summary score in the overweight sample. This suggests that replacing SED with MPA or VPA may have some benefits on cardiometabolic health.

Interrupting Prolonged Sitting and Endothelial Function in Polycystic Ovary Syndrome.

In healthy adults, the impairment of vascular function associated with prolonged sitting can be mitigated with intermittent brief bouts of activity. It is unknown whether these benefits extend to women with polycystic ovary syndrome (PCOS), in whom vascular function is typically impaired and sitting time is high. We examined the acute effect of regularly interrupting sitting time with brief simple resistance activities (SRA) on vascular function in PCOS. In a randomized crossover trial, 13 physically inactive women with PCOS (18-45 yr) completed two 3.5-h conditions: 1) uninterrupted sitting (SIT) and 2) sitting interrupted by 3-min bouts of SRA every 30 min. Femoral artery flow-mediated dilation (FMD), resting shear rate, and resting blood flow were measured at 0, 1, and 3.5 h. Mean resting femoral shear rate, averaged across the 3.5 h, significantly increased in the SRA condition relative to the SIT condition (40.1 ± 6.1 vs 62.8 ± 6.1 s-1, P < 0.0001). In addition, mean resting blood flow also significantly increased across the 3.5 h for SRA relative to SIT (45.0 ± 9.8 vs 72.8 ± 9.9 mL·min-1, P < 0.0001). There were no differences between conditions in the temporal change in femoral artery FMD across 3.5 h (Ptime-condition > 0.05 for all). Frequently interrupting sitting with SRA acutely increased resting shear rate and blood flow in women with PCOS but did not alter FMD. With sedentary behavior increasing in prevalence, longer-term studies of similar interventions to reduce and break up sitting time are warranted.

Effect of football activity and physical fitness on information processing, inhibitory control and working memory in adolescents

BackgroundWhilst an acute bout of exercise has been shown to enhance subsequent cognition, including in adolescents, the effects of team games (of which Football is the most popular) has received little attention. Therefore, this study examined: the effect of an acute bout of outdoor Football activity on information processing, inhibitory control, working memory and circulating brain-derived neurotrophic factor (BDNF) in adolescents; the effect of physical fitness on cognition and; the moderating effect of physical fitness on the acute exercise responses.MethodsFollowing familiarisation, 36 adolescents (16 girls) took part in two trials (60-min Football and 60-min seated rest) separated by 7-d in a counterbalanced, crossover design. Information processing and inhibitory control (Stroop Test), and working memory (Sternberg Paradigm) were assessed 30-min before exercise/rest and immediately, 45- and 90-min post-exercise/rest. Capillary blood samples were obtained before exercise/rest and up to 120-min post-exercise/rest. The median split of distance covered on the MSFT was used to divide the group into high- and low-fit groups.ResultsPerformance on the cognitive function tasks was similar between Football and seated rest (trial*time interactions; all p > .05). However, the high-fit group had overall quicker response times on both levels of the Stroop Task and all three levels of the Sternberg Paradigm (main effect of fitness; all p < .001). Furthermore, the exercise-cognition relationship was moderated by physical fitness, with improvements in working memory response times seen post-exercise, only in the high-fit group (trial*time*fitness interaction, p < .05). Circulating BDNF was unaffected by the Football activity and physical fitness (p > .05).ConclusionThe present study shows that higher levels of physical fitness are beneficial for cognitive function and provides novel evidence that an ecologically valid, and popular, form of exercise is beneficial for working memory following exercise, in high-fit participants only.

The relative influence of nature vs. nurture on the expression of circatidal rhythms in the American horseshoe crab Limulus polyphemus

The horseshoe crabLimulus polyphemusexhibits rhythmic locomotor behavior that is controlled by both internal clocks and external tidal cycles. Recent findings demonstrate that adult horseshoe crabs from a 2 tides d-1environment usually express 2 bouts of activity d-1, while adults from areas with 1 dominant tide d-1, or with negligible tides (atidal), generally express 1 bout of activity d-1. Horseshoe crabs from these different environments are genetically distinct, so it is not known if these behavioral differences are driven by genetics or by the tides they experience early in life. To address this question, freshly spawned horseshoe crab eggs from populations that experience these 3 distinct environmental tidal regimes were reared in the laboratory under 1 of the above 3 artificial tidal conditions. Then the activity of individual larval and 2ndinstar juveniles was recorded over 3 wk using video tracking software. Endogenous circatidal rhythms were present in most (88/108) of the freshly molted juveniles from all 3 populations, even when they were raised in atidal conditions, indicating a strong genetic influence. To our knowledge, this is the first demonstration of the presence of genetically driven endogenous circatidal rhythms in an individual juvenile marine organism. Nevertheless, the early environment was also capable of having an impact, because it significantly affected rhythm expression in crabs in the 1 tide d-1population. Thus, overall, the tidal environment to which horseshoe crab eggs are exposed during development appears to have less of an influence than genetics on their expression of tidal rhythms of locomotion.