BackgroundActivity trackers are increasingly popular with both consumers and researchers for monitoring activity and for promoting positive behavior change. However, there is a lack of research investigating the performance of these devices in free-living contexts, for which findings are likely to vary from studies conducted in well-controlled laboratory settings.ObjectiveThe aim was to compare Fitbit One and Jawbone UP estimates of steps, moderate-to-vigorous physical activity (MVPA), and sedentary behavior with data from the ActiGraph GT3X+ accelerometer in a free-living context.MethodsThirty-two participants were recruited using convenience sampling; 29 provided valid data for this study (female: 90%, 26/29; age: mean 39.6, SD 11.0 years). On two occasions for 7 days each, participants wore an ActiGraph GT3X+ accelerometer on their right hip and either a hip-worn Fitbit One (n=14) or wrist-worn Jawbone UP (n=15) activity tracker. Daily estimates of steps and very active minutes were derived from the Fitbit One (n=135 days) and steps, active time, and longest idle time from the Jawbone UP (n=154 days). Daily estimates of steps, MVPA, and longest sedentary bout were derived from the corresponding days of ActiGraph data. Correlation coefficients and Bland-Altman plots with examination of systematic bias were used to assess convergent validity and agreement between the devices and the ActiGraph. Cohen’s kappa was used to assess the agreement between each device and the ActiGraph for classification of active versus inactive (≥10,000 steps per day and ≥30 min/day of MVPA) comparable with public health guidelines.ResultsCorrelations with ActiGraph estimates of steps and MVPA ranged between .72 and .90 for Fitbit One and .56 and .75 for Jawbone UP. Compared with ActiGraph estimates, both devices overestimated daily steps by 8% (Fitbit One) and 14% (Jawbone UP). However, mean differences were larger for daily MVPA (Fitbit One: underestimated by 46%; Jawbone UP: overestimated by 50%). There was systematic bias across all outcomes for both devices. Correlations with ActiGraph data for longest idle time (Jawbone UP) ranged from .08 to .19. Agreement for classifying days as active or inactive using the ≥10,000 steps/day criterion was substantial (Fitbit One: κ=.68; Jawbone UP: κ=.52) and slight-fair using the criterion of ≥30 min/day of MVPA (Fitbit One: κ=.40; Jawbone UP: κ=.14).ConclusionsThere was moderate-strong agreement between the ActiGraph and both Fitbit One and Jawbone UP for the estimation of daily steps. However, due to modest accuracy and systematic bias, they are better suited for consumer-based self-monitoring (eg, for the public consumer or in behavior change interventions) rather than to evaluate research outcomes. The outcomes that relate to health-enhancing MVPA (eg, “very active minutes” for Fitbit One or “active time” for Jawbone UP) and sedentary behavior (“idle time” for Jawbone UP) should be used with caution by consumers and researchers alike.

ABSTRACT32 , the product of the rpoH gene in Escherichia coli, provides promoter specificity by interacting with core RNAP. Amino acid sequence alignment of 32 with other sigma factors in the 70 family has revealed regions of sequence homology. We have investigated the function of the most highly conserved region, 2.2, using purified products of various rpoH alleles. Core RNAP binding analysis by glycerol gradient sedimentation has revealed reduced core RNAP affinity for one of the mutant 32 proteins, Q80R. This reduced core interaction is exacerbated in the presence of 70 , which competes with 32 for binding of core RNAP. When a different but more conserved amino acid was introduced at this position by site-directed mutagenesis (Q80N), this mutant sigma factor still displayed a significant reduction in its core RNAP affinity. Based on these results, we conclude that at least one specific amino acid in region 2.2 is involved in core RNAP interaction.In eubacteria there exist a number of different sigma factors that are involved in the expression of specific sets of genes. The primary sigma factor controls the expression of primary housekeeping genes, and a number of alternative sigma factors regulate gene expression at specific stages of growth, or as a response to outside stimuli. In spite of the diversity of sigma factors, they all have similar activities during transcription initiation (reviewed in refs. 1 and 2). They direct transcription initiation by interacting with core subunits of RNA polymerase to form a holoenzyme, by recognizing the Ϫ10 and Ϫ35 regions of DNA promoters, and by stabilizing the separation of DNA strands. Ultimately, the sigma factor, at least in the case of 70 , dissociates from the rest of the RNAP, and the core RNAP subunit enters the elongation phase of transcription.

In this sample of office workers, real time computer prompts facilitated the impact of a participatory approach on reductions in occupational sedentary exposure, and increases in physical activity.

IntroductionManagement of osteoarthritis (OA) includes the use of non-pharmacological and pharmacological therapies. Although walking is commonly recommended for reducing pain and increasing physical function in people with OA, glucosamine sulphate has also been used to alleviate pain and slow the progression of OA. This study evaluated the effects of a progressive walking program and glucosamine sulphate intake on OA symptoms and physical activity participation in people with mild to moderate hip or knee OA.MethodsThirty-six low active participants (aged 42 to 73 years) were provided with 1500 mg glucosamine sulphate per day for 6 weeks, after which they began a 12-week progressive walking program, while continuing to take glucosamine. They were randomized to walk 3 or 5 days per week and given a pedometer to monitor step counts. For both groups, step level of walking was gradually increased to 3000 steps/day during the first 6 weeks of walking, and to 6000 steps/day for the next 6 weeks. Primary outcomes included physical activity levels, physical function (self-paced step test), and the WOMAC Osteoarthritis Index for pain, stiffness and physical function. Assessments were conducted at baseline and at 6-, 12-, 18-, and 24-week follow-ups. The Mann Whitney Test was used to examine differences in outcome measures between groups at each assessment, and the Wilcoxon Signed Ranks Test was used to examine differences in outcome measures between assessments.ResultsDuring the first 6 weeks of the study (glucosamine supplementation only), physical activity levels, physical function, and total WOMAC scores improved (P < 0.05). Between the start of the walking program (Week 6) and the final follow-up (Week 24), further improvements were seen in these outcomes (P < 0.05) although most improvements were seen between Weeks 6 and 12. No significant differences were found between walking groups.ConclusionsIn people with hip or knee OA, walking a minimum of 3000 steps (~30 minutes), at least 3 days/week, in combination with glucosamine sulphate, may reduce OA symptoms. A more robust study with a larger sample is needed to support these preliminary findings.Trial RegistrationAustralian Clinical Trials Registry ACTRN012607000159459.

The findings highlight the potential benefits of standing or active deskwork to the allocation of attentional resources and the regulation of stress.