Detecting bouts of physical activity in a field setting.

The purposes of this study were to assess the TRITRAC and CSA for: (a) interaccelerometer agreement; (b) agreement in detecting patterns of moderate-intensity physical activity; and (c) agreement in detecting walking patterns recorded in a diary. Thirty-one women wore both the TRITRAC and CSA accelerometers for three consecutive days. Interaccelerometer agreement (measured with generalizability coefficients) ranged from .88 to .99. In total, 71.3% of the accelerometers' patterns agreed in length, with CSA patterns being on average significantly longer. Interaccelerometer agreement in detecting patterns of brisk walking, as recorded in a diary, was comparable (69.4%). Interaccelerometer discrepancies may be related in part to the threshold employed by each instrument for classifying moderate intensity patterns.     

Validation of a commercially available inertial measurement unit for recording jump load in youth basketball players

ABSTRACT

A high incidence of overuse knee injuries among youth basketball players may be attributed to number of jumps. Wearable technology may be an effective tool for measuring jump load compared to traditional counting methods. The purpose of this study was to validate a commercially available jump counter (VERT® Classic) in youth basketball practices and games, and to identify the characteristics (i.e., height, direction, takeoff) of jumps recorded by the VERT® Classic. 46 (19F, 27M) youth basketball players wore a VERT® Classic and were recorded on video during games and practices. The number of jumps recorded by the VERT® Classic and evaluated by video raters were compared for each jump characteristic using intraclass correlation coefficient (ICC(3,k)), mean offset, and limits of agreement. The number and percent of VERT® Classic jumps and corresponding video jumps according to timestamp were reported. VERT® Classic jumps had excellent reliability with video-counted jumps over 15 cm (ICC(3,k) = 0.958), with a mean offset of ?2.4 jumps (fewer VERT® Classic) and limits of agreement ?12.6 to 7.8 jumps. Pairs of corresponding jumps represented 68.0% of total video jumps and 92.0% of VERT® Classic jumps. The VERT® Classic can provide an estimate of jump load in youth basketball.     

Do habitual foot-strike patterns in running influence functional Achilles tendon properties during gait?

ABSTRACT

The capacity of foot-strike running patterns to influence the functional properties of the Achilles tendon is controversial. This study used transmission-mode ultrasound to investigate the influence of habitual running foot-strike pattern on Achilles tendon properties during barefoot walking and running. Fifteen runners with rearfoot (RFS) and 10 with a forefoot (FFS) foot-strike running pattern had ultrasound transmission velocity measured in the right Achilles tendon during barefoot walking (≈1.1 ms^?1) and running (≈2.0 ms^?1). Temporospatial gait parameters, ankle kinematics and vertical ground reaction force were simultaneously recorded. Statistical comparisons between foot-strike patterns were made using repeated measure ANOVAs. FFS was characterised by a significantly shorter stance duration (?4%), greater ankle dorsiflexion (+2°), and higher peak vertical ground reaction force (+20% bodyweight) than RFS running (P < .05). Both groups adopted a RFS pattern during walking, with only the relative timing of peak dorsiflexion (3%), ground reaction force (1–2%) and peak vertical force loading rates (22–23%) differing between groups (P < .05). Peak ultrasound transmission velocity in the Achilles tendon was significantly higher in FFS during walking (≈100 ms^?1) and running (≈130 ms^?1) than RFS (P < .05). Functional Achilles tendon properties differ with habitual footfall patterns in recreational runners.     

Validity of the iPhone M7 motion co-processor as a pedometer for able-bodied ambulation

Physical activity benefits for disease prevention are well-established. Smartphones offer a convenient platform for community-based step count estimation to monitor and encourage physical activity. Accuracy is dependent on hardware–software platforms, creating a recurring challenge for validation, but the Apple iPhone® M7 motion co-processor provides a standardised method that helps address this issue. Validity of the M7 to record step count for level-ground, able-bodied walking at three self-selected speeds, and agreement with the StepWatch^TM was assessed. Steps were measured concurrently with the iPhone® (custom application to extract step count), StepWatch^TM and manual count. Agreement between iPhone® and manual/StepWatch^TM count was estimated through Pearson correlation and Bland-Altman analyses. Data from 20 participants suggested that iPhone® step count correlations with manual and StepWatch^TM were strong for customary (1.3 ± 0.1 m/s) and fast (1.8 ± 0.2 m/s) speeds, but weak for the slow (1.0 ± 0.1 m/s) speed. Mean absolute error (manual–iPhone®) was 21%, 8% and 4% for the slow, customary and fast speeds, respectively. The M7 accurately records step count during customary and fast walking speeds, but is prone to considerable inaccuracies at slow speeds which has important implications for certain patient groups. The iPhone® may be a suitable alternative to the StepWatch^TM for only faster walking speeds.     

Comparison of total energy expenditure assessed by two devices in controlled and free-living conditions

Abstract

The objective of this study was to evaluate the validity of total energy expenditure (TEE) provided by Actiheart^® and Armband^®. Normal-weight adult volunteers wore both devices either for 17 hours in a calorimetric chamber (CC, n = 49) or for 10 days in free-living conditions (FLC) outside the laboratory (n = 41). The two devices and indirect calorimetry or doubly labelled water, respectively, were used to estimate TEE in the CC group and FLC group. In the CC, the relative value of TEE error was not significant (p > 0.05) for Actiheart^® but significantly different from zero for Armband^®, showing TEE underestimation (?4.9%, p < 0.0001). However, the mean absolute values of errors were significantly different between Actiheart^® and Armband^®: 8.6% and 6.7%, respectively (p = 0.05). Armband^® was more accurate for estimating TEE during sleeping, rest, recovery periods and sitting–standing. Actiheart^® provided better estimation during step and walking. In FLC, no significant error in relative value was detected. Nevertheless, Armband^® produced smaller errors in absolute value than Actiheart^® (8.6% vs. 12.8%). The distributions of differences were more scattered around the means, suggesting a higher inter-individual variability in TEE estimated by Actiheart^® than by Armband^®. Our results show that both monitors are appropriate for estimating TEE. Armband^® is more effective than Actiheart^® at the individual level for daily light-intensity activities.     

The novel use of a SenseCam and accelerometer to validate training load and training information in a self-recall training diary

Self-recall training diaries are a frequently used tool to quantify training load and training information. While accelerometers are predominantly used to validate training diaries, they are unable to validate contextual training information. Thus this study aimed to examine the novel use of data fusion from a wearable camera device (SenseCam) and accelerometer to validate a self-recall training diary. Thirty participants filled in a training diary for 1 day while simultaneously wearing a SenseCam and accelerometer. The training diary was validated using Bland–Altman plots, Spearman’s rank-order correlation, percentage agreement and κ measure of agreement between the diary and the SenseCam and accelerometer. The results demonstrated overall agreement, and no bias, between the training diary and the accelerometer for training intensity, and the SenseCam for duration of activity and travel time. A positive correlation was found for duration (r = 0.82, P < 0.001) and intensity (r = 0.67, P < 0.001). Hundred per cent agreement was found between the SenseCam and training diary for activity, training surface and footwear (κ = 1, P < 0.0001), with a lower agreement noted for sports played (97.3%, κ = 0.91, P < 0.0001). The self-recall training diary was found to be a valid measure of capturing training load and training information using the combined wearable camera device and accelerometer.     

Determining motions with an IMU during level walking and slope and stair walking

ABSTRACT

This study investigated whether using an inertial measurement unit (IMU) can identify different walking conditions, including level walking (LW), descent (DC) and ascent (AC) slope walking as well as downstairs (DS) and upstairs (US) walking. Thirty healthy participants performed walking under five conditions. The IMU was stabilised on the exterior of the left shoe. The data from IMU were used to establish a customised prediction model by cut point and a prediction model by using deep learning method. The accuracy of both prediction models was evaluated. The customised prediction model combining the angular velocity of dorsi–plantar flexion in the heel-strike (HS) and toe-off (TO) phases can distinctly determine real conditions during DC and AC slope, DS, and LW (accuracy: 86.7–96.7%) except for US walking (accuracy: 60.0%). The prediction model established by deep learning using the data of three-axis acceleration and three-axis gyroscopes can also distinctly identify DS, US, and LW with 90.2–90.7% accuracy and 84.8% and 82.4% accuracy for DC and AC slope walking, respectively. In conclusion, inertial measurement units can be used to identify walking patterns under different conditions such as slopes and stairs with customised prediction model and deep learning prediction model.     

Alterations in neuromuscular activation patterns associated with walking in short-leg walking boots

BackgroundShort-leg walking boots are a common intervention for acute and chronic lower extremity injury. Few studies have examined the neuromuscular adaptations associated with short-leg walking boots and no previous study has investigated timing characteristics of muscle activation during gait. The purpose of the current study was to examine the timing and amplitudes of muscle activation of the extrinsic ankle musculature during walking in two types of short-leg walking boots.MethodsEleven healthy young adults performed five level walking trials at a self-selected pace in each of three conditions: normal walking, Gait Walker and Equalizer short-leg walking boots. Ground reaction forces were collected from a force platform while surface electromyography (EMG) was collected from the tibialis anterior, peroneus longus and medial gastrocnemius. EMG signals were rectified and smoothed using the root mean squared with a 20-ms smoothing window and were normalized to the largest mean of the normal walking trials. A repeated measures analysis of variance was used to assess the effect of short-leg walking boots on the onset, duration and amplitude of muscle activation.ResultsShort-leg walking boots were generally associated with earlier onsets of muscle activation and longer durations of muscle activation. However, there was no reduction in EMG amplitude.ConclusionThe findings of this study show that the induced alterations in muscle activation patterns may limit the short-leg walking boots.     

Comparison of treadmill and over-ground Nordic walking

Abstract

The purpose of this study was to compare the physiological responses of Nordic walking on a specially designed treadmill and Nordic walking on a level over-ground surface. Thirteen participants completed three 1-h Nordic walking training sessions. Following the training sessions, each participant performed two 1600-m over-ground Nordic walking trials at a self-selected pace. Each participant then completed two 1600-m Nordic walking treadmill trials on a Hammer Nordic Walking XTR Treadmill®, at the mean walking speed of their two over-ground Nordic walking trials. Breath-by-breath analysis of oxygen uptake ([Vdot]O₂) and heart rate was performed during each trial. Caloric expenditure was calculated using the [Vdot]O₂. Rating of perceived exertion (RPE) was assessed at the end of each trial. We found no significant differences in physiological variables collected during the two over-ground Nordic walking trials or the two treadmill Nordic walking trials. Mean walking speed was 106.96±11.49 m · min^?1. Mean heart rate during treadmill walking (99±13 beats · min^?1) was 22% lower than that during the over-ground condition (126±17 beats · min^?1). Mean [Vdot]O₂ and mean caloric expenditure were also lower during treadmill walking (15.18±3.81 ml · min^?1 · kg^?1, 0.08±0.02 kcal · min^?1 · kg^?1) than over-ground walking (24.16±4.89 ml · min^?1 · kg^?1, 0.12±0.02 kcal · min^?1 · kg^?1). Analysis of variance demonstrated that all variables were significantly higher during over-ground Nordic walking (P<0.001). A Mann-Whitney U-test demonstrated that the RPE for over-ground Nordic walking was greater than that for treadmill Nordic walking (P=0.02). Thus over-ground Nordic walking created a greater physiological stress than treadmill Nordic walking performed at the same speed and distance. The reason for this difference may have been the relatively narrow walking and poling decks on the treadmill, which made it difficult for the participants to place their poles correctly and maintain a consistent walking pattern. This would decrease the contribution of the arm muscles to overall oxygen consumption. In conclusion, the Hammer Nordic Walking XTR Treadmill® does not replicate the physiological stress of over-ground Nordic walking. Increasing the width of the decks could eliminate the discrepancy.     

Agreement in activity energy expenditure assessed by accelerometer and self-report in adolescents: Variation by sex,age, and weight status

Abstract

The agreement between self-reported and objective estimates of activity energy expenditure was evaluated in adolescents by age, sex, and weight status. Altogether, 403 participants (217 females, 186 males) aged 13–16 years completed a 3-day physical activity diary and wore a GT1M accelerometer on the same days. Partial correlations (controlling for body mass) were used to determine associations between estimated activity energy expenditure (kcal · min^?1) from the diary and accelerometry. Differences in the magnitude of the correlations were examined using Fisher's r to z transformations. Bland–Altman procedures were used to determine concordance between the self-reported and objective estimates. Partial correlations between assessments of activity energy expenditure (kcal · min^?1) did not differ significantly by age (13–14 years: r = 0.41; 15–16 years: r = 0.42) or weight status (normal weight: r = 0.42; overweight: r = 0.39). The magnitude of the association was significantly affected by sex (Δr = 0.11; P < 0.05). The agreement was significantly higher in males than in females. The relationship between activity energy expenditure assessed by the objective method and the 3-day diary was moderate (controlling for weight, correlations ranged between 0.33 and 0.44). However, the 3-day diary revealed less agreement in specific group analyses; it markedly underestimated activity energy expenditure in overweight/obese and older adolescents. The assessment of activity energy expenditure is complex and may require a combination of methods.     

Walking cadence required to elicit criterion moderate-intensity physical activity is moderated by fitness status

ABSTRACT

The aims of this study were to estimate the walking cadence required to elicit a VO₂reserve (VO₂R) of 40% and determine if fitness status moderates the relationship between walking cadence and %VO₂R. Twenty participants (10 male, mean(s) age 32(10) years; VO₂max 45(10) mL·kg^?1·min^?1) completed resting and maximal oxygen consumption tests prior to 7 x 5-min bouts of treadmill walking at increasing speed while wearing an Apple Watch and measuring oxygen consumption continuously. The 7 x 5-min exercise bouts were performed at speeds between 3 and 6 km·h^?1 with 5-min seated rest following each bout. Walking cadence measured at each treadmill speed was recorded using the Apple Watch “Activity” app. Using Bayesian regression, we predict that participants need a walking cadence of 138 to 140 steps·min^?1 to achieve a VO₂R of 40%. However, these values are moderated by fitness status such that those with lower fitness can achieve 40% VO₂R at a slower walking cadence. The results suggest that those with moderate fitness need to walk at ~40% higher than the currently recommended walking cadence (100 steps·min^?1) to elicit moderate-intensity physical activity. However, walking cadence required to achieve moderate-intensity physical activity is moderated by fitness status.     

Validity of a trunk-mounted accelerometer to assess peak accelerations during walking,jogging and running

Abstract

The purpose of this study was to validate peak acceleration data from an accelerometer contained within a wearable tracking device while walking, jogging and running. Thirty-nine participants walked, jogged and ran on a treadmill while 10 peak accelerations per movement were obtained (n = 390). A single triaxial accelerometer measured resultant acceleration during all movements. To provide a criterion measure of acceleration, a 12-camera motion analysis (MA) system tracked the position of a retro-reflective marker affixed to the wearable tracking device. Peak raw acceleration recorded by the accelerometer significantly overestimated peak MA acceleration (P < 0.01). Filtering accelerometer data improved the relationship with the MA system (P < 0.01). However, only the 10 Hz and 8 Hz cut-off frequencies significantly reduced the errors found. The walk movement demonstrated the highest accuracy, agreement and precision and the lowest relative errors. Linear increases in error were observed for jog compared with walk and for run compared to both other movements. As the magnitude of acceleration increased, the strength of the relationship between the accelerometer and the criterion measure decreased. These results indicate that filtered accelerometer data provide an acceptable means of assessing peak accelerations, in particular for walking and jogging.     

Physical fitness percentiles for Portuguese children and adolescents aged 10–18 years

Abstract

This study aimed to produce age- and sex-specific physical fitness reference data for Portuguese youth; to report the prevalence of youth in the healthy zone of physical fitness according to the FITNESSGRAM^® criteria; to verify the agreement between the Portuguese physical fitness percentiles and the FITNESSGRAM^® healthy zones. In 2008, 22,048 Portuguese children and adolescents (10–18 years) were evaluated. Physical fitness (curl-ups, push-ups, 20-m shuttle run and modified-back-saver-sit-and-reach tests) was evaluated using the FITNESSGRAM^® Test Battery 8.0. Smoothed percentile curves were estimated using Cole’s LMS method. Boys consistently outperformed girls in every physical fitness test, except for the modified-back-saver-sit-and-reach tests. In both sexes and for all physical fitness tests, higher percentile values were observed at older ages. The 50th percentile of all physical fitness tests had the highest accuracy to discriminate between under healthy zone and healthy zone of the FITNESSGRAM^®. Portuguese schools and physical education teachers may considerer the 50th percentile for age and sex or the FITNESSGRAM^® criteria for classifying participants in the healthy zone as acceptable cut-offs, above which youth should be considered fit. These reference values can be used as normative data and for baseline values for subsequent surveillance of the physical fitness of Portuguese youth.     

Comparison of accelerometer cut points to estimate physical activity in US adults

Abstract

The purpose of this study was (1) to describe physical activity prevalence, categorised according to the 2008 Physical Activity Guidelines for Americans (2008 Guidelines), using different accelerometer cut points and (2) to examine physical activity prevalence patterns by reported cut points across selected characteristics. Cut points from 9 studies were used to estimate physical activity prevalence in a national adult sample (n = 6547). Estimates were stratified by validation study activity protocols used to derive cut points – ambulatory (walking/running) and lifestyle activities (e.g. gardening, housework, walking). Results showed that the prevalence of meeting the 2008 Guidelines ranged from 6.3% to 98.3% overall and was lower for cut points derived from ambulatory (median = 11.5%, range = 6.3–27.4%) compared to lifestyle (median = 77.2%, range = 60.6–98.3%) protocols. Prevalence patterns across protocols differed for age, but were similar for other characteristics. In conclusion, prevalence of meeting the 2008 Guidelines varied widely, indicating that choice of cut point had an impact on prevalence. To generate future accelerometer cut points one may consider developing cut points for demographic subgroups using a variety of lifestyle physical activities.     

Comparison of Body Composition Estimates among Norland Elite®, Lunar iDXA®, and the BodPod® in Overweight to Obese Adults

ABSTRACT

Accurate body composition assessment, which includes fat mass (adipose tissue mass, FM), fat-free mass (FFM), and percent fat mass (%FM) is needed to evaluate health and treatment efficacy. The current study compared body composition estimates obtained from the Norland Elite® DXA, BodPod®, and iDXA® before and after a12-week exercise intervention in adults (n=30, BMI 25–35 kg/m²) . Bland-Altman methods determined mean bias and limits of agreement for FM, %FM, and FFM between methods. Compared to the iDXA® and BodPod®, Elite® overestimated BF% and FM (P < .01). FFM was similar between iDXA® and Elite® but lower in Elite® than BodPod® (P < .01). There were no differences between methods in changes in FM or FFM after the exercise intervention. Prior to this study, it was unknown how the Norland Elite®, a DXA model marketed to bariatric surgery patients, compared to other common body composition assessment methodologies..     

Development and Psychometric Testing of the Dogs and WalkinG Survey (DAWGS)

Purpose

Dog owners represent 40% of the population, a promising audience to increase population levels of physical activity. The purpose of this study was to develop and test the psychometric properties of a new instrument to assess social-cognitive theory constructs related to dog walking.

Method

Dog owners (N = 431) completed the Dogs and WalkinG Survey (DAWGS). Survey items assessed dog-walking behaviors and self-efficacy, social support, outcome expectations, and outcome expectancies for dog walking. Test–retest reliability was assessed among 252 (58%) survey respondents who completed the survey twice. Factorial validity and factorial invariance by age and walking level were tested using confirmatory factor analysis.

Results

DAWGS items demonstrated moderate test–retest reliability (ρ = .39–.79; k = .41–.89). Acceptable model fit was found for all subscales. All subscales were invariant by age and walking level, except self-efficacy, which showed mixed evidence of invariance.

Conclusions

The DAWGS is a psychometrically sound instrument for examining individual and interpersonal correlates of dog walking.     

Walking pace and the risk of stroke: A meta-analysis of prospective cohort studies

PurposeThe extent to which walking pace is associated with a reduced risk for stroke remains unclear. This study examined the association between walking pace and stroke risk based on prospective cohort studies.MethodsDatabases of PubMed, EMBASE, Web of Science, Scopus, and China National Knowledge Internet were searched from the inception dates to January 31, 2019, for prospective cohort studies focusing on walking pace and risk of stroke in adults. Two reviewers independently extracted data and assessed the quality of the studies. The dependent measure was stroke incidence. Using random-effects models, a meta-analysis was performed to estimate the overall relative risks (RR) of stroke incidence and 95% confidence intervals (CIs) for the individuals with the fastest walking paces vs. individuals with the slowest walking paces. A dose-response relationship was also examined.ResultsAfter screening 1294 titles/abstracts and 14 full-text studies identified in the search, 7 studies (from 8 cohorts) were included in the meta-analysis. The 7 studies included a total of 135,645 participants (95.2% women; mean age 63.6 years) and 2229 stroke events (median follow-up time = 8.0 years). Compared to individuals in the slowest walking-pace category (median = 1.6 km/h), individuals in the fastest walking-pace category (median = 5.6 km/h) had a 44% lower risk of stroke (pooled RR = 0.56, 95%CI: 0.48–0.65). There was also a linear dose-response relationship (RR = 0.87; 95%CI: 0.83–0.91), with the risk of stroke decreased by 13% for every 1 km/h increment in baseline walking pace. We observed similar results across walking-pace assessment, type of stroke ascertainment, stroke subtypes, sex, sample size, and duration of follow-up.ConclusionFindings from this meta-analysis indicate that walking pace is inversely associated with the risk of stroke.     

Utility and Reliability of an App for the System for Observing Play and Recreation in Communities (iSOPARC®)

The app for the System for Observing Play and Recreation in Communities (iSOPARC®) was developed to enhance System for Observing Play and Recreation in Communities data collection and management. The study aim was to examine the usability and inter-rater reliability of iSOPARC®. Trained observers collected data in 16 park areas in two Latin America cities (Curitiba, Brazil; Bogotá, Colombia) using both the original System for Observing Play and Recreation in Communities (mechanical counter) and new iSOPARC® (electronic counter) methods. A total of 8,707 park users (3,958 females and 4,749 males) were observed. Reliabilities among observers were determined using the intraclass correlation coefficient and relative overall agreement (%) in three ways: (a) mechanical versus mechanical, (b) mechanical versus electronic, and (c) electronic versus electronic. When both used mechanical counters comparisons overall agreement was over 78% (intraclass correlation coefficient = .982; p < .001) for variables in all analysis. When one used a mechanical counter and the other used electronic (iSOPARC®) comparisons overall agreement was higher for age (84%; p < .001) than for physical activity (83%; p < .001) variables and average intraclass correlation coefficient was .965. Using both used iSOPARC® comparisons overall agreement was 81% to physical activity and 83% to age group. Results suggest iSOPARC® can be used reliably for examining variables previously validated in System for Observing Play and Recreation in Communities.     

Kinematic characteristics of elite men's 50 km race walking

Abstract

Race walking is an endurance event which also requires great technical ability, particularly with respect to its two distinguishing rules. The 50 km race walk is the longest event in the athletics programme at the Olympic Games. The aims of this observational study were to identify the important kinematic variables in elite men's 50 km race walking, and to measure variation in those variables at different distances. Thirty men were analysed from video data recorded during a World Race Walking Cup competition. Video data were also recorded at four distances during the European Cup Race Walking and 12 men analysed from these data. Two camcorders (50 Hz) recorded at each race for 3D analysis. The results of this study showed that walking speed was associated with both step length (r=0.54,P=0.002) and cadence (r=0.58,P=0.001). While placing the foot further ahead of the body at heel strike was associated with greater step lengths (r=0.45,P=0.013), it was also negatively associated with cadence (r= ?0.62,P<0.001). In the World Cup, knee angles ranged between 175 and 186° at initial contact and between 180 and 195° at midstance. During the European Cup, walking speed decreased significantly (F=9.35,P=0.002), mostly due to a decrease in step length between 38.5 and 48.5 km (t=8.59,P=0.014). From this study, it would appear that the key areas a 50 km race walker must develop and coordinate are step length and cadence, although it is also important to ensure legal walking technique is maintained with the onset of fatigue.