Physical activity,motor competence and movement and gait quality: A principal component analysis

ObjectiveWhile novel analytical methods have been used to examine movement behaviours, to date, no studies have examined whether a frequency-based measure, such a spectral purity, is useful in explaining key facets of human movement. The aim of this study was to investigate movement and gait quality, physical activity and motor competence using principal component analysis.MethodsSixty-five children (38 boys, 4.3 ± 0.7y, 1.04 ± 0.05 m, 17.8 ± 3.2 kg, BMI; 16.2 ± 1.9 kg∙m²) took part in this study. Measures included accelerometer-derived physical activity and movement quality (spectral purity), motor competence (Movement Assessment Battery for Children 2nd edition; MABC2), height, weight and waist circumference. All data were subjected to a principal component analysis, and the internal consistency of resultant components were assessed using Cronbach's alpha.ResultsTwo principal components, with excellent internal consistency (Cronbach α >0.9) were found; the 1st principal component, termed “movement component”, contained spectral purity, traffic light MABC2 score, fine motor% and gross motor% (α = 0.93); the 2nd principal component, termed “anthropometric component”, contained weight, BMI, BMI% and body fat% (α = 0.91).ConclusionThe results of the present study demonstrate that accelerometric analyses can be used to assess motor competence in an automated manner, and that spectral purity is a meaningful, indicative, metric related to children's movement quality.     

Bodyweight support alters the relationship between preferred walking speed and cost of transport

Humans tend to select a preferred walking speed (PWS) that minimizes the metabolic energy consumed per distance traveled, i.e. the Cost of Transport (CoT). The aims of this study were to: 1. compare PWS overground vs. on a treadmill at 100 and 50% of body weight, and 2. explore whether with body weight support, PWS corresponds to the speed that minimizes CoT. Fifteen healthy adults walked overground and on a lower body positive pressure treadmill with and without bodyweight support. Walking speeds (m^.s⁻¹) were recorded for each condition. Rate of energy expenditure (J^.kg^−1.min⁻¹) and CoT (J^.kg^−1.m⁻¹) were then determined from 5-min walking trials with 50% bodyweight support at PWS and ± 30% of the self-selected walking speed for that condition. PWS did not differ across conditions. With 50% body weight support, for each 30% increase in walking speed, rates of metabolic energy expenditure increased ∼15% while CoT decreased by ∼14%. Thus, with 50% body weight support, PWS did not correspond with the speed that minimized CoT. Bodyweight support decreases cost of maintaining an upright body but does not decrease the metabolic demand of limb advancement, contributing to the linear yet not proportional changes in rates of energy expenditure and CoT. We conclude that bodyweight support via an AlterG® treadmill disconnects the association between PWS and minimum CoT. These findings have implications for clinical populations (e.g., obese, elderly) who may benefit from walking on a bodyweight supporting treadmill but may select speeds incompatible with their physical activity goals.     

The Effect of Auditory Cueing on the Spatial and Temporal Gait Coordination in Healthy Adults

Walk ratio, defined as step length divided by cadence, indicates the coordination of gait. During free walking, deviation from the preferential walk ratio may reveal abnormalities of walking patterns. The purpose of this study was to examine the impact of rhythmic auditory cueing (metronome) on the neuromotor control of gait at different walking speeds. Forty adults (mean age 26.6 ± 6.0 years) participated in the study. Gait characteristics were collected using a computerized walkway. In the preferred walking speed, there was no significant difference in walk ratio between uncued (walk ratio = .0064 ± .0007 m/steps/min) and metronome-cued walking (walk ratio = .0064 ± .0007 m/steps/min; p = .791). A higher value of walk ratio at the slower speed was observed with metronome-cued (walk ratio = .0071 ± .0008 m/steps/min) compared to uncued walking (walk ratio = .0068 ± .0007 m/steps/min; p < .001). The walk ratio was less at faster speed with metronome-cued (walk ratio = .0060 ± .0009 m/steps/min) compared to uncued walking (walk ratio = .0062 ± .0009 m/steps/min; p = .005). In healthy adults, the metronome cues may become an attentional demanding task, and thereby disrupt the spatial and temporal integration of gait at nonpreferred speeds.     

Gaze behaviour during walking in young adults with developmental coordination disorder

BackgroundIndividuals with Developmental Coordination Disorder (DCD) experience difficulty with motor coordination and this affects their daily functioning. Research indicated inferior visuospatial processing and oculomotor control in DCD. As visual information is essential for locomotor control, more insight in the gaze behaviour of this population during walking is required and crucial for gaze training interventions as a possible means to improve daily functioning of children and adults with DCD.AimThis study explored differences and similarities in gaze behaviour during walking between typically developing young adults and those with DCD.Methods and proceduresTen young adults with DCD (age: 22.13 ± 0.64) and ten typically developing individuals (age: 22.00 ± 1.05) completed a walking task in which they had to place their feet on irregularly placed targets wearing eye tracking glasses.Outcomes and resultsIndividuals with DCD walked slower and demonstrated a different gaze strategy compared to their neurotypical peers as they fixated almost each and every target sequentially. Typically developing individuals, on the other hand, directed gaze further along the path and often fixated areas around the targets.Conclusions and implicationsDespite adequate walking performance in daily situations in young adults with DCD, fundamental control deficits persist into adulthood.What this paper adds?This paper is the first to demonstrate differences in gaze behaviour between young adults with DCD and typically developing individuals in a task that resembles a task of daily living, as previous research focused on laboratory tasks. This is a valuable finding as DCD has a clear impact on the daily life. Furthermore, this study demonstrated that the fundamental control deficits of DCD persist into adulthood despite frequent performance and practice of these daily tasks. Lastly, these findings might contribute to the therapeutic potential of gaze training interventions to improve the daily functioning of children and adults with DCD.     

Cadence (steps/min) as an indicator of the walk-to-run transition

BackgroundHumans naturally transition from walking to running at a point known as the walk-to-run transition (WRT). The WRT commonly occurs at a speed of ∼2.1 m/s (m/s) or a Froude number (dimensionless value considering leg length) of 0.5. Emerging evidence suggests the WRT can also be classified using a cadence of 140 steps/min. An accurate cadence-based WRT metric would aid in classifying wearable technology minute-level step metrics as walking vs. running.PurposeTo evaluate performance of 1) WRT predictors directly identified from a treadmill-based dataset of sequentially faster bouts, and 2) accepted WRT predictors compiled from previous literature.MethodsTwenty-eight adults (71.4% men; age = 36.6 ± 12.8 years, BMI = 26.2 ± 4.7 kg/m²) completed a series of five-minute treadmill walking bouts increasing in 0.2 m/s increments until they freely chose to run. Optimal WRT values for speed, Froude number, and cadence were identified using receiver operating characteristic (ROC) curve analyses. WRT value performance was evaluated via classification accuracy metrics.ResultsOverall accuracies (metric, percent) according to WRT predictors from previous literature were: speed (2.1 m/s, 55.0%), Froude number (0.5, 76.8%), and cadence (140 steps/min, 91.1%), and those from the dataset herein were: speed (1.9 and 2.0 m/s, 78.6%), Froude number (0.68, 77.3%), and cadence (134, 139, and 141 steps/min, 92.9%). The three equally accurate cadence values support a heuristic range of cadence-based WRT values in young and middle-aged adults: 135–140 steps/min.SignificanceA tight range of cadence values performed better as WRT predictors compared to either previously reported or directly identified speed or Froude number values. These findings have important implications for gait classification, especially considering cadence is a simple metric which can be readily assessed across settings using direct observation or wearable technologies.     

Self-efficacy for health-related behaviour change in patients with TIA or minor ischemic stroke

Abstract

Objective: To assess levels of self-efficacy for health-related behaviour change and its correlates in patients with TIA or ischemic stroke.

Methods: In this prospective cohort study, 92 patients with TIA or ischemic stroke completed questionnaires on self-efficacy for health-related behaviour change and fear, social support and depressive symptoms. Relations between fear, social support, depressive symptoms, cognitive impairment, vascular risk factors and history and demographic characteristics and low-self-efficacy were studied with univariable and multivariable logistic regression.

Results: Median total self-efficacy score at baseline was 4 (IQR 4–5). Older age (OR 1.05, 95% CI 1.01–1.09), depressive symptoms (OR 1.09, 95% CI 1.03–1.16), presence of vascular history (OR 2.42, 95% CI 0.97–6.03), higher BMI (OR 1.15, 95% CI 1.01–1.30), fear (OR 1.06, 95% CI 1.01–1.12) and low physical activity (OR 1.49, 95% CI 1.01–2.21) were significantly associated with low self-efficacy.

Conclusion: Patients with recent TIA or ischemic stroke report high self-efficacy scores for health-related behaviour change. Age, vascular history, more depressive symptoms, higher BMI, less physical activity and fear were correlates of low self-efficacy levels.

Practice implications: These correlates should be taken into account in the development of interventions to support patients in health behaviour change after TIA or ischemic stroke.     

Affective responses to 10-minute and 30-minute walks in sedentary,overweight women: Relationships with theory-based correlates of walking for exercise

ObjectivesThe purpose of this study was to examine affective responses to 10-min and 30-min walks among sedentary, overweight women. Secondary purposes were to: a) examine differences in theory-based correlates of future participation in walking for exercise; and b) determine if the affective responses were related to these correlates.Design/MethodsTwenty-three sedentary, overweight women (M age = 26.62 years; BMI = 33.53 kg/m²) completed 10-min walk, 30-min walk, and quiet rest (QR) control conditions. Affective responses were assessed prior to, during, and following each condition. Self-efficacy and intention for regular participation in multiple 10-min walks or single 30-min walks for exercise during the next month were also assessed post-exercise.Results/ConclusionsAnalyses revealed that improvements in affective responses (p < 0.05) emerged during and following both walking sessions while no benefits were observed with QR. Self-efficacy (p < 0.01) and intention (p < 0.01) to walk for exercise in the future were significantly higher for multiple 10-min walks. Correlation analyses demonstrated that affective responses were most strongly and consistently correlated with intention and self-efficacy for future participation following the 10-min walk. These findings demonstrate that, while both walks resulted in similar affective benefits, sedentary, overweight women reported greater intention and self-efficacy to participate in multiple brief walks for exercise in the future.     

Partial body weight support treadmill training speed influences paretic and non-paretic leg muscle activation,stride characteristics,and ratings of perceived exertion during acute stroke rehabilitation

BackgroundIntensive task-specific training is promoted as one approach for facilitating neural plastic brain changes and associated motor behavior gains following neurologic injury. Partial body weight support treadmill training (PBWSTT), is one task-specific approach frequently used to improve walking during the acute period of stroke recovery (<1 month post infarct). However, only limited data have been published regarding the relationship between training parameters and physiologic demands during this early recovery phase.ObjectiveTo examine the impact of four walking speeds on stride characteristics, lower extremity muscle demands (both paretic and non-paretic), Borg ratings of perceived exertion (RPE), and blood pressure.DesignA prospective, repeated measures design was used.MethodsTen inpatients post unilateral stroke participated. Following three familiarization sessions, participants engaged in PBWSTT at four predetermined speeds (0.5, 1.0, 1.5 and 2.0 mph) while bilateral electromyographic and stride characteristic data were recorded. RPE was evaluated immediately following each trial.ResultsStride length, cadence, and paretic single limb support increased with faster walking speeds (p ⩽ 0.001), while non-paretic single limb support remained nearly constant. Faster walking resulted in greater peak and mean muscle activation in the paretic medial hamstrings, vastus lateralis and medial gastrocnemius, and non-paretic medial gastrocnemius (p ⩽ 0.001). RPE also was greatest at the fastest compared to two slowest speeds (p < 0.05).ConclusionsDuring the acute phase of stroke recovery, PBWSTT at the fastest speed (2.0 mph) promoted practice of a more optimal gait pattern with greater intensity of effort as evidenced by the longer stride length, increased between-limb symmetry, greater muscle activation, and higher RPE compared to training at the slowest speeds.     

Motivational,volitional and multiple goal predictors of walking in people with type 2 diabetes

BackgroundType 2 diabetes is a major public health problem. Effective diabetes self-management involves people engaging in multiple health behaviours, including physical activity. Walking is an effective, accessible and inexpensive form of physical activity, yet many people with Type 2 diabetes do not meet recommended levels. The present study aimed to: 1) identify demographic, motivational and volitional factors predictive of walking in people with Type 2 diabetes mellitus, and 2) test whether accounting for the perceived impact of other goal pursuits (goal facilitation and goal conflict) improved the prediction of walking.MethodsA theory-based cross-sectional study using the Health Action Process Approach was conducted in adults with Type 2 diabetes across Scotland. Assuming a 50% response rate 1000 questionnaires were mailed to achieve the target sample size (N = 500). Demographic information was collected, and intentional (outcome expectations, social support, risk perceptions), motivational (intention, self-efficacy), volitional (action planning, action control) and multiple goal (goal conflict, goal facilitation) factors were assessed as predictors of physical activity in general and walking specifically.ResultsThe final sample comprised 411 respondents. The majority (60%) were non-adherent to physical activity recommendations. Of 411 respondents, 356 provided walking data. Body Mass Index and age were the only demographic and anthropometric factors predictive of walking (overall R² = 0.04). When motivational factors were added, intention and self-efficacy added to the prediction (overall R² = 0.07). When volitional factors were added, only action control was predictive of walking (overall R² = 0.08). Finally, goal facilitation explained an additional 7% variance in walking when added to the model (final overall R² = 0.15).ConclusionThere was low adherence with physical activity recommendations in general and walking in particular. When testing predictors of motivational, volitional and competing goal constructs together, action control and goal facilitation emerged as predictors of walking. Future research should consider how walking can be embedded synergistically alongside other goal pursuits and how action control may help to ensure that they are pursued.     

EEG neurofeedback improves cycling time to exhaustion

ObjectiveThe role of the brain in endurance performance is frequently debated; surprisingly, few investigations have attempted to improve endurance performance by directly targeting brain activity. One promising but untested approach to modifying brain activity is electroencephalogram (EEG) neurofeedback. Consequently, our experiment is the first to examine an EEG neurofeedback intervention for whole-body endurance performance.MethodWe adopted a two-part experiment. The first consisted of a randomized parallel controlled design. Forty participants were allocated to three experimental groups; increase relative left cortical activity (NFL), increase relative right (NFR), and passive control (CON). They performed a depleting cognitive task, followed by either six 2-min blocks of EEG neurofeedback training (NFL or NFR) or time-matched videos of the neurofeedback display (CON). Next, they performed a time-to-exhaustion (TTE) test on a cycle-ergometer. We then tested participants of NFL and NFR groups in an additional experimental visit and administered the opposite neurofeedback training within a fully repeated-measures protocol.ResultsEEG neurofeedback modified brain activity as expected. As hypothesized, the NFL group cycled for over 30% longer than the other groups in the parallel controlled design, NFL: 1382 ± 252 s, NFR: 878 ± 167, CON: 963 ± 117 s. We replicated this result in the repeated-measures design where NFL: 1167 ± 831 s performed 11% longer than NFR: 1049 ± 638 s. There were no differences in pre-exercise fatigue, vigor or self-control; area under the curve group-differences for perceived effort were interpreted within a goal persistence framework.ConclusionThe brief EEG neurofeedback intervention elicited greater relative left frontal cortical activity and enhanced endurance exercise performance.     

Transcranial alternating brain stimulation at alpha frequency reduces hemispatial neglect symptoms in stroke patients

Background/ObjectiveNon-invasive brain stimulation techniques such as transcranial alternating current stimulation (tACS) may help alleviate attention deficits in stroke patients with hemispatial neglect by modulating oscillatory brain activity. We applied high-definition (HD)-tACS at alpha frequency over the contralesional hemisphere to support unilateral oscillatory alpha activity and correct for the pathologically altered attention bias in neglect patients.MethodsWe performed a within-subject, placebo-controlled study in which sixteen stroke patients with hemispatial neglect underwent 10 Hz (alpha) as well as sham (placebo) stimulation targeting the contralesional posterior parietal cortex. Attentional bias was measured with a computerized visual detection paradigm and two standard paper-and-pencil neglect tests.ResultsWe revealed a significant shift of attentional resources after alpha-HD-tACS, but not sham tACS, toward the ipsilateral and thus contralesional hemifield leading to a reduction in neglect symptoms, measured with a computerized visual detection paradigm and a widely used standard paper and pencil neglect tests.ConclusionsWe showed a significant alpha-HD-tACS-induced shift of attentional resources toward the contralesional hemifield, thus leading to a reduction in neglect symptoms. Importantly, HD-tACS effects persisted after the stimulation itself had ended. This tACS protocol, based on intrinsic oscillatory processes, may be an effective and well-tolerated treatment option for neglect.     

Neuropsychological sequelae following pediatric stroke: A nonlinear model of age at lesion effects

Aim: The distribution and quality of brain recovery following pediatric arterial ischemic stroke remains controversial. The literature suggests that age at stroke may be an important modulator of neuropsychological outcome, with reports inferring either greater vulnerability or plasticity in the nascent brain. Our aim was to investigate neuropsychological outcomes following pediatric stroke in a clinical sample with reference to age at lesion, lesion laterality, elapsed time from stroke to assessment, and persistent neurological sequelae.

Methods: Using comprehensive neuropsychological assessment batteries, we investigated retrospectively a large (n?=?44) and evenly distributed group of children who had ischemic stroke during “infancy” (1 month to 1 year), “early childhood” (1 to 6 years), and “late childhood” (6 to 16 years).

Results: Children who suffered a stroke performed significantly worse on a range of neuropsychological measures when compared to a normative sample. However, children who suffered a stroke between 1 and 6 years old demonstrated better preserved neuropsychological profiles than either the earlier (before age 1) or later (after age 6) age groups. In addition, those children suffering a left hemisphere lesion performed more poorly on a range of neuropsychological measures than did children with right hemisphere lesions.

Interpretation: Age at stroke is an important determinant of recovery following insult and may modulate neuropsychological and cognitive outcome.     

Coach autonomy support predicts autonomous motivation and daily moderate-to-vigorous physical activity and sedentary time in youth sport participants

ObjectiveGuided by self-determination theory (Deci & Ryan, 1987), this study tested a trans-contextual model linking perceptions of the social environment created by the youth sport coach to levels of autonomous and controlled motivation, and objectively measured daily moderate-to-vigorous physical activity (MVPA) and sedentary time (ST) in young football players.DesignThe study employed a cross-sectional design, assessing physical activity using accelerometers.Method105 male youth sport footballers (M age = 12.79 ± 1.85 years) wore a GT3X accelerometer for 7 days. Measures of height and weight were recorded. Participants completed a multi-section questionnaire assessing perceptions of autonomy support and controlling coaching behaviours, and motivation toward their participation in sport and physically active games.ResultsPath analysis supported a model in which players’ perceptions of coach-provided autonomy support positively predicted autonomous motivation for sport engagement. In turn, autonomous motivation was positively associated with MVPA, and negatively related to ST (min/day). Controlling coach behaviours were positively linked to controlled motivation. However, controlled motivation for sport and physically active games was unrelated to daily MVPA and ST. Perceptions of coach-provided autonomy support had a significant positive indirect effect on daily MVPA, and a significant negative indirect effect on daily ST.ConclusionsResults suggest that autonomy supportive coach behaviours are related to daily physical activity patterns in young male footballers. Theory-based interventions that aim to encourage autonomy supportive coaching, and subsequently foster autonomous reasons for sport engagement, may enhance the potential of youth sport for increasing daily MVPA and reducing ST among children and adolescents active in this setting     

Variability in trunk and pelvic movement of transfemoral amputees using a C-leg system compared to healthy controls

ObjectiveGait variability is a measure of gait disturbance, and therefore constitutes a useful parameter for gait assessment as well as planning of therapeutic and medical interventions. To date, variability during walking has not been adequately analyzed in amputees. The aim of this examination was to evaluate trunk and pelvic movement variability in transfemoral amputees. The effect of different types of walking surfaces on variability in trunk and pelvic movement was also studied.MethodThis prospective clinical examination compares 20 transfemoral amputees (17 ♂, 42 ± 16 years; 3 ♀, 48 ± 3 years) with a group of 20 age and mass matched healthy controls regarding the extent of variability in trunk and pelvic movement. Kinematic data of trunk and pelvic movement during walking on level, uneven ground and slope was captured by eight infrared cameras (Vicon Nexus ™, Oxford, UK). Variability in trunk and pelvic movement was analyzed. Univariate ANCOVA and ANOVA with repeated measures and post hoc tests were used for statistical comparison. Fall history was retrospectively collected from medical history to assess the association between falls and variability in trunk and pelvic movement.ResultsTrunk and pelvic movement variability in amputees was significantly higher during walking on uneven ground and slope compared to healthy controls (p ≤ 0.05). Variability in trunk and pelvic movement was increased during walking on uneven ground and slope compared to even ground for both groups (p ≤ 0.05).ConclusionAmputees showed increased trunk and pelvic movement variability during walking on uneven ground and slope, indicating an affected gait pattern in comparison to healthy controls. Therefore, trunk and pelvic movement variability could be a potential marker for gait quality with diagnostic implications.     

The role of the Self in assessing doping cognition: Implicit and explicit measures of athletes’ doping-related prototype perceptions

ObjectivesTo examine athletes’ implicit and explicit prototype perceptions of performance enhancing substance (PES) users and non-users.DesignA cross-sectional mixed-method study.MethodsCompetitive athletes from 39 sports (N = 226; mean age = 27.66 ± 9.74 years; 59% male) completed four self-report questions and two Brief Implicit Association Tests online, assessing prototype favourability and similarity of PES users and non-users.ResultsAthletes explicitly associated themselves with a non-user (M = 3.13 ± 0.92) more than a PES user (M = 0.56 ± 0.88) and perceived a non-user (M = 89.92 ± 14.98) more favourably than a PES user (M = 13.18 ± 21.38). Indexing behaviour on self-reports, doping contemplators did not differ from ‘clean’ athletes in their perceptions of PES user prototypes while dopers perceived PES users favourably and similar to themselves. In comparison, doping contemplators paired the concept of 'dopers' easier with themselves than with others, while clean athletes and dopers had no preference for either pairing (D = −0.33, -0.08 and 0.01, respectively). All groups demonstrated some degree of preference for ‘good and doper’, moving from slight to moderate to strong preference in the groups of clean athletes, dopers and contemplators, respectively (D = −0.20, −0.37 and −0.80, respectively).ConclusionsResults suggest that doping contemplators may have a positive bias towards doping which is not endorsed in self-reports. Implicit preferences, along with the disparity between the implicit and explicit measures of athletes’ doping-related prototype perceptions advance understanding of doping behaviour and make a unique contribution to research methodology. Factors influencing the interplay between explicit and implicit endorsements of PES user prototypes warrant further research.     

Reliability of transcranial magnetic stimulation measurements of maximum activation of the knee extensors in young adult males

Purpose

• •Transcranial magnetic stimulation (TMS) provides an indication of changes occurring in the corticospinal pathway. This study aimed to determine the between-day (trials 1 week apart) and within-day (trials 1 h apart) reliability of TMS and peripheral nerve stimulation.

Methods

• •22 male participants (age 23 ± 4 years; height 1.80 ± 0.07 m; body mass 75.1 ± 11.7 kg; body mass index 23.1 ± 2.5 kg.m⁻²) completed 2 familiarisation sessions and 3 experimental trials (trial 2 and 3 split by 1 h). The interpolated twitch technique was used to determine TMS-assessed voluntary activations (VA-_TMS) superimposed on submaximal and maximal leg extension performed on a custom-built dynamometer. Reliability was assessed using equivalence tests, systematic error, 95% limits of agreement, intraclass correlation coefficient (ICC) and coefficient of variation (CV).

Results

• •VA-_TMS was equivalent between-day (94.1 ± 4.4% versus 93.7 ± 4.9%, P < 0.01) and within-day (93.7 ± 4.9% versus 93.7 ± 4.8%, P < 0.01). Systematic error (95% limits of agreement) for VA-_TMS was −0.5% (−5.1%, 4.2%) for between-day and − 0.0% (−5.3%, 5.4%) for within-day. ICC and CV values demonstrated high reliability between-day (ICC = 0.93, CV = 2.5%) and within-day (ICC = 0.92, CV = 2.9%).

Conclusion

• •Results indicate that TMS can reliably estimate the output of the motor cortex to the knee extensors, both between-day and within-day. The findings have been used to estimate sample sizes for this technique for future research.

     

Identifying Beneficial Physical Activity During School Recess: Utility and Feasibility of the Fitbit

The purpose of the current study was to assess the utility, feasibility, and reliability of Fitbit accelerometers to measure physical activity (via steps) of 15 young children simultaneously during recess. Fitbit-recorded steps per minute (SPM) were used as the primary measure to assess levels of activity in children playing in various structured (i.e., instructed) and unstructured (i.e., free play) recess activities. The results suggested that the number of steps measured by two Fitbits resulted in high levels of agreement, and the Fitbits were successful at identifying differential levels of activity across multiple types of play activities. Across all children, running or walking was associated with the most SPM (M = 89) and highest percentage of moderate-to-vigorous physical activity (MVPA; M = 47%), followed by soccer (M = 58 SPM; M = 12% MVPA), free play (M = 53 SPM; 3% MVPA), and tag (M = 43 SPM; 7% MVPA). The utility of the Fitbit’s minute-by-minute data records was demonstrated, with the use of additional third-party software by Python, as differential levels of physical activity associated with various play behaviors were detected, and all 15 participants were assessed simultaneously with very few observers.     

Three consecutive nights of sleep loss: Effects of morning caffeine consumption on subjective sleepiness/alertness,reaction time and simulated driving performance

Caffeinated products are often consumed as a popular countermeasure to the effects of sleep loss. However, the efficacy of caffeine to exert these effects after consecutive nights of sleep loss is poorly understood. The aim of this study was to investigate the effects of three consecutive nights of restricted sleep and morning caffeine consumption on subjective ratings of sleepiness/alertness, reaction time, and simulated driving performance. Twenty healthy, habitual caffeine consumers (11 females; age: 23.3 ± 5.7 y; BMI: 22.3 ± 3.5 kg⋅m⁻²; caffeine intake: 204 ± 89 mg⋅day⁻¹; Mean ± SD) who had normal sleeping patterns (≥8 h⋅night⁻¹) participated in this double-blind, placebo-controlled, randomised study. Following one night of normal sleep (≥8 h time in bed (TIB)), participants underwent three consecutive nights of restricted sleep (5 h TIB). Participants received caffeine (200 mg; n = 10) or placebo (n = 10) capsules each morning and all participants received caffeine (100 mg) capsules each afternoon. Subjective ratings of alertness, concentration and tiredness were measured before and 1 h after morning capsule administration. Choice Reaction Time (CRT) was examined 1 h after morning capsule administration, with response speed and accuracy as outcome variables. Driving performance was assessed using a 30 min simulated driving task, with lateral (standard deviation of lane position [SDLP]; total number of line crossings [LC]) and longitudinal (standard deviation of speed [SDSP]) measures of vehicle control as outcome variables. Alertness and concentration significantly decreased, and tiredness increased across the three days of sleep loss. Caffeine only marginally alleviated these effects. No differences were observed between treatments or across trial days for response speed and accuracy on the CRT task. Likewise, no significant differences were observed between groups or across trial days for any measures of simulated driving performance. Overall, results from this study indicate that three consecutive days of sleep loss influence subjective ratings of alertness, concentration and tiredness, but does not alter CRT or simulated driving performance. Caffeine may alleviate some of the negative subjective effects imposed by restricted sleep, but the efficacy of caffeine to attenuate performance changes in CRT and driving performance were unable to be observed.     

Quantifying lower limb inter-joint coordination and coordination variability after four-month wearing arch support foot orthoses in children with flexible flat feet

IntroductionFlat feet in children negatively affect lower limb alignment and cause adverse health-related problems. The long-term application of foot orthoses (FOs) may have the potential to improve lower limb coordination and its variability.AimTo evaluate the effects of long-term use of arch support FOs on inter-joint coordination and coordination variability in children with flexible flat feet.MethodsThirty boys with flexible flat feet were randomly assigned to the experimental (EG) and control groups. The EG used medial arch support FOs during daily activities over a four-month period while the control group received a flat 2-mm-thick insole for the same time period. Lower-limb coordination and variability during the 3 sub-stance phases were quantified using a vector coding technique.ResultsFrontal plane ankle-hip coordination in EG during mid-stance changed to an anti-phase pattern (156.9^°) in the post-test compared to an in-phase (221.1^°) in the pre-test of EG and post-test of CG (222.7). Frontal plane knee-hip coordination in EG during loading response (LR) changed to an anti-phase pattern (116^°) in the post-test compared to an in-phase (35.5^°) in the pre-test of EG and post-test of CG (35.3). Ankle inversion/eversion-knee internal/external rotation joint coupling angle in EG changed to an in-phase pattern (59^°) in the post-test compared to a proximal phase (89^°) in the pre-test. Coupling angle variability increased in the post-test of EG for sagittal plane ankle-hip during push-off, transverse plane ankle-hip during LR and mid-stance, and transverse plane knee-hip during LR and mid-stance compared to pre-test of EG and post-test of CG.ConclusionThe long-term use of arch support FOs proved to be effective to alter lower limb coordination and coordination variability during walking in children with flexible flat feet. This new insight into coordinative function may be useful for improving corrective exercise strategies planned for children with flat feet.     

Acute effects of jaw clenching using a customized mouthguard on anaerobic ability and ventilatory flows

The latest findings on the ergogenic effects of a dentistry-design, bite-aligning mouthpiece require additional research to assess its impact on anaerobic ability and ventilatory parameters. This paper was aimed at determining the ergogenic acute effects of wearing a custom-made mouthpiece on oral airflow dynamics, 30-s Wingate Anaerobic Test performance parameters.Twenty-eight healthy and physically-active male subjects (age: 24.50 ± 3.32, height: 181.34 ± 7.4, weight: 78.14 ± 8.21), were voluntarily studied. The subjects were first briefed on the test protocols, and then performed the 30 s Wingate test and Spirometer test. The experimental trials were performed in a random counterbalanced order. We evaluate maximum expiratory volume (V_Emax L min⁻¹), mean power (W kg⁻¹), peak power (W kg⁻¹), time to peak (s), rate to fatigue (W s⁻¹) and lactate production (mMol L⁻¹), rate of perceived exertion (RPE).There were significant differences between mouthguard and no-mouthguard conditions in mean power (W kg⁻¹), peak power (W kg⁻¹), time to peak (s), and rate to fatigue (W s⁻¹) for the 30-s Wingate Anaerobic Test. Significantly lower lactate production (mMol L⁻¹) was observed, in mouthguard condition but no significant differences were found in RPE. In airflow dynamics, the V_Emax L min⁻¹ was significantly higher when comparing the mouthguard and the no mouthguard conditions in both forced and unforced conditions.In conclusion, wearing a customized mouthguard improves anaerobic ability and increases forced expiratory volume. This study will help practitioners improve athlete’s performance in anaerobic activities where high intensity action might provoke jaw-clenching, contributing in reductions of lactate and fatigue, and improving ventilatory parameters.