Classification of occupational activity categories using accelerometry: NHANES 2003-2004.

BACKGROUND: An individual's occupational activity (OA) may contribute significantly to daily physical activity (PA) and sedentary behavior (SB). However, there is little consensus about which occupational categories involve high OA or low OA, and the majority of categories are unclassifiable with current methods. The purpose of this study was to present population estimates of accelerometer-derived PA and SB variables for adults (n = 1112, 20-60 years) working the 40 occupational categories collected during the 2003-2004 National Health and Nutrition Examination Survey (NHANES). METHODS: ActiGraph accelerometer-derived total activity counts/day (TAC), activity counts/minute, and proportion of wear time spent in moderate-to-vigorous PA [MVPA], lifestyle, and light PA organized by occupational category were ranked in ascending order and SB was ranked in descending order. Summing the ranks of the six accelerometer-derived variables generated a summary score for each occupational category, which was re-ranked in ascending order. Higher rankings indicated higher levels of OA, lower rankings indicated lower levels of OA. Tertiles of the summary score were used to establish three mutually exclusive accelerometer-determined OA groupings: high OA, intermediate OA, and low OA. RESULTS: According to their summary score, 'farm and nursery workers' were classified as high OA and 'secretaries, stenographers, and typists' were classified as low OA. Consistent with previous research, some low OA occupational categories (e.g., 'engineers, architects, and scientists', 'technicians and related support occupations', 'management related occupations', 'executives, administrators, and managers', 'protective services', and 'writers, artists, entertainers, and athletes') associated with higher education and income had relatively greater amounts of MVPA compared to other low OA occupational categories, likely due to the greater percentage of men in those occupations and/or the influence of higher levels of leisure time PA. Men had more TAC, activity counts/minute and time in MVPA, but similar proportions of SB compared to women in all three OA groupings. CONCLUSIONS: Objectively measured PA allowed for a more precise estimate of the amount of PA and SB associated with different occupations and facilitated systematic classification of the 40 different occupational categories into three distinct OA groupings. This information provides new opportunities to explore the relationship between OA and health outcomes.

Where the rubber meets the road: Emerging environmental impacts of tire wear particles and their chemical cocktails.

About 3 billion new tires are produced each year and about 800 million tires become waste annually. Global dependence upon tires produced from natural rubber and petroleum-based compounds represents a persistent and complex environmental problem with only partial and often-times, ineffective solutions. Tire emissions may be in the form of whole tires, tire particles, and chemical compounds, each of which is transported through various atmospheric, terrestrial, and aquatic routes in the natural and built environments. Production and use of tires generates multiple heavy metals, plastics, PAH's, and other compounds that can be toxic alone or as chemical cocktails. Used tires require storage space, are energy intensive to recycle, and generally have few post-wear uses that are not also potential sources of pollutants (e.g., crumb rubber, pavements, burning). Tire particles emitted during use are a major component of microplastics in urban runoff and a source of unique and highly potent toxic substances. Thus, tires represent a ubiquitous and complex pollutant that requires a comprehensive examination to develop effective management and remediation. We approach the issue of tire pollution holistically by examining the life cycle of tires across production, emissions, recycling, and disposal. In this paper, we synthesize recent research and data about the environmental and human health risks associated with the production, use, and disposal of tires and discuss gaps in our knowledge about fate and transport, as well as the toxicology of tire particles and chemical leachates. We examine potential management and remediation approaches for addressing exposure risks across the life cycle of tires. We consider tires as pollutants across three levels: tires in their whole state, as particulates, and as a mixture of chemical cocktails. Finally, we discuss information gaps in our understanding of tires as a pollutant and outline key questions to improve our knowledge and ability to manage and remediate tire pollution.

Muscle Damage, Inflammation, and Muscular Performance following the Physical Ability Test in Professional Firefighters.

Proper monitoring of fatigue and muscular damage may be used to decrease the high levels of cardiovascular disease, overuse musculoskeletal injuries, and workers compensation claims within the profession of firefighting. The purpose of this study was to examine muscle damage, muscular fatigue, and inflammation responses following a typical firefighting shift. Twenty-four professional firefighters completed two Physical Ability Tests to standardize the tasks typically performed in a day of work, and to elicit similar physiological responses. Participants were then monitored for 48 h. Prior to, and 48 h following the Physical Ability Tests, participants were evaluated for changes in strength, power, range-of-motion, as well as blood markers including myoglobin and c-reactive protein. Following the Physical Ability Tests, significant differences in myoglobin (p < 0.05), grip strength (p < 0.05), vertical jump (p < 0.05), and sit-and-reach (p < 0.05) were observed. No difference in c-reactive protein was observed (p > 0.05). After 24 hours following a shift, firefighters exhibited decreased strength, power, and range-of-motion. This may lead to decreases in performance and an increased risk of injury.

Overweight and obese humans overeat away from home.

The built environment has been implicated in the development of the epidemic of obesity. We investigated the differences in the meal patterns of normal weight vs. overweight/obese individuals occurring at home vs. other locations. The location of meals and their size in free-living participants were continuously recorded for 7 consecutive days. Study 1: 81 males and 84 females recorded their intake in 7-day diet diaries and wore a belt that contained a GPS Logger to record their location continuously for 7 consecutive days. Study 2: 388 males and 621 females recorded their intake in diet diaries for 7 consecutive days. In both studies, compared to eating at home, overweight/obese participants ate larger meals away from home in both restaurants and other locations than normal weight participants. Overweight/obese individuals appear to be more responsive to environmental cues for eating away from home. This suggests that the influence of the built environment on the intake of overweight/obese individuals may contribute to the obesity epidemic.

Acute Supplementation with Cannabidiol Does Not Attenuate Inflammation or Improve Measures of Performance following Strenuous Exercise.

Supplementation with cannabidiol (CBD) may expedite recovery when consumed after exercise. The purpose of this study was to determine if supplementation with CBD reduces inflammation and enhances performance following strenuous eccentric exercise in collegiate athletes. Twenty-four well-trained females (age = 21.2 ± 1.8 years, height = 166.4 ± 8 cm, weight = 64.9 ± 9.1 kg) completed 100 repetitions of unilateral eccentric leg extension to induce muscle damage. In this crossover design, participants were randomized to receive 5 mg/kg of CBD in pill form or a placebo 2 h prior to, immediately following, and 10 h following muscle damage. Blood was collected, and performance and fatigue were measured prior to, and 4 h, 24 h, and 48 h following the muscle damage. Approximately 28 days separated treatment administration to control for the menstrual cycle. No significant differences were observed between the treatments for inflammation, muscle damage, or subjective fatigue. Peak torque at 60°/s (p = 0.001) and peak isometric torque (p = 0.02) were significantly lower 24 h following muscle damage, but no difference in performance was observed between treatments at any timepoint. Cannabidiol supplementation was unable to reduce fatigue, limit inflammation, or restore performance in well-trained female athletes.

Focused Microbiome Shifts in Reconstructed Wetlands Correlated with Elevated Copper Concentrations Originating from Micronized Copper Azole-Treated Wood.

Micronized copper (Cu) azole (MCA) wood preservative formulations include Cu in nano form, and relatively little is known about longer term effects of Cu leached from MCA into wetland ecosystems. We tested the hypothesis that changes in soil microbiomes within reconstructed freshwater wetlands will be associated with exposure to elevated Cu concentrations originating from immersed MCA-treated wood stakes. Eight replicate communities were assembled with Willamette Valley (OR, USA) flood plain soil and clonally propagated wetland plants within mesocosms. Inundated communities were equilibrated for 5 months before installation of MCA or control southern yellow pine stakes (n = 4 communities/experimental group). Soil samples were collected for 16S and internal transcribed spacer amplicon sequencing to quantify responses in prokaryotes and eukaryotes, respectively, at 15 time points, spanning two simulated seasonal dry downs, for up to 678 days. Physiochemical properties of water and soil were monitored at 20 and 12 time points respectively, over the same period. For both taxonomic groups of organisms, phylogenetic diversity increased and was positively correlated with elapsed days. Furthermore, there was significant divergence among eukaryotes during the second year based on experimental group. Although the composition of taxa underwent succession over time, there was significantly reduced relative abundance of sequence variants from Gomphonema diatoms and Scutellinia fungi in communities where MCA wood stakes were present compared with the controls. These focused microbiome shifts were positively correlated with surface water Cu and soil Cu concentrations, which were significantly elevated in treated communities. The reconstructed communities were effective systems for assessing potential impacts to wetland microbiomes after exposure to released copper. The results further inform postcommercialization risk assessments on MCA-treated wood. Environ Toxicol Chem 2021;40:3351-3368. Published 2021. This article is a U.S. Government work and is in the public domain in the USA.

Relationship between leptin, adiponectin, bone mineral density, and measures of adiposity among pre-menopausal Hispanic and Caucasian women.

OBJECTIVE: The purpose of this study was to examine the relationship between fasting serum leptin and adiponectin levels with bone mineral density (BMD) and body composition in pre-menopausal, middle-aged Hispanic and Caucasian women. OBJECTIVE: Participants' (68 Hispanic and 36 Caucasian) BMD and bone mineral content were measured by dual-energy X-ray absorptiometry, and body density was measured by hydrodensitometry. Serum leptin was determined by enzyme immunoassay and adiponectin by ELISA. RESULTS: Hispanic women had significantly higher leptin, BMD, and fat mass (FM), and lower adiponectin than Caucasian women. There was no significant correlation between leptin and BMD for Hispanic or Caucasian women; adiponectin was inversely correlated with BMD in Caucasian women only (p = 0.01). In both Hispanic and Caucasian women, lean body mass and adiponectin best explained the variance in BMD (r(2) = 0.25, p < 0.001). CONCLUSION: These data demonstrate no significant relationship between leptin and BMD of pre-menopausal, middle-aged Hispanic and Caucasian women, and a significant inverse relationship between adiponectin and BMD in Caucasian women. The role of adipocytokines in the regulation of BMD remains inconclusive and may vary across ethnic groups.

Relationship of leptin, resting metabolic rate, and body composition in premenopausal hispanic and non-Hispanic White women.

OBJECTIVE: The purpose was to evaluate the relationships between fasting serum leptin, resting metabolic rate (RMR), and body composition in premenopausal Hispanic and non-Hispanic White (White) women. METHODS: Participants were 67 Hispanic and 43 White women who arrived at the laboratory in a fasted state for measurement of RMR by indirect calorimetry, bone mineral content measured by dual-energy X-ray absorptiometry, and body density measured by hydrodensitometry. Serum leptin levels were determined by EIA. RESULTS: Multiple regression analysis revealed that body mass and lean body mass were the best predictors of RMR. Leptin was not a significant predictor of RMR. CONCLUSION: Further research needs to be done to examine the role of leptin on metabolism, especially in ethnic groups predisposed to development of obesity and related disorders.

Exercise-Induced Improvements in Insulin Sensitivity Are Not Attenuated by a Family History of Type 2 Diabetes.

Introduction: A family history of type 2 diabetes (FH+) is a major risk factor for the development of insulin resistance and type 2 diabetes. However, it remains unknown whether exercise-induced improvements in insulin sensitivity and metabolic flexibility are impacted by a FH+. Therefore, we investigated whether improvements in insulin sensitivity, metabolic flexibility, body composition, aerobic fitness and muscle strength are limited by a FH+ following eight weeks of combined exercise training compared to individuals without a family history of type 2 diabetes (FH-). Methods: Twenty (n = 10 FH-, n = 10 FH+) young, healthy, sedentary, normoglycemic, Mexican-American males (age: FH- 22.50 ± 0.81, FH+ 23.41 ± 0.86 years; BMI: FH- 27.91 ± 1.55, FH+ 26.64 ± 1.02 kg/m2) underwent eight weeks of combined aerobic and resistance exercise training three times/week (35 min aerobic followed by six full-body resistance exercises). Insulin sensitivity was assessed via hyperinsulinemic euglycemic clamps. Metabolic flexibility was assessed by the change in respiratory quotient from fasted to insulin-stimulated states. Body composition was determined using dual-energy x-ray absorptiometry. Aerobic fitness was determined by a graded exercise test, and upper- and lower-body strength were assessed via one-repetition maximum bench press and leg strength dynamometer, respectively. Results: Insulin sensitivity, metabolic flexibility, aerobic fitness and strength were not different between groups (p > 0.05). Eight weeks of combined aerobic and resistance exercise training improved insulin sensitivity (FH- p = 0.02, FH+ p = 0.002), increased fat free mass (FH- p = 0.006, FH+ p = 0.001), aerobic fitness (FH- p = 0.03, FH+ p = 0.002), and upper- (FH- p = 0.0001, FH+ p = 0.0001) and lower-body strength (FH- p = 0.0009, FH+ p = 0.0003), but did not change metabolic flexibility (p > 0.05) in both groups. Exercise-induced improvements in metabolic outcomes were similar between groups. Conclusions: Insulin sensitivity, metabolic flexibility, aerobic fitness and strength were not compromised by a FH+. Additionally, a FH+ is not a limiting factor for exercise-induced improvements in insulin sensitivity, aerobic fitness, body composition, and strength in normoglycemic young Mexican-American men.

The effects of manual resistance training on improving muscular strength and endurance.

The purpose of this study was to investigate the effects of a manual resistance training (MRT) program on muscular strength and endurance and to compare these effects with those of an identically structured weight resistance training (WRT) program. To do this, 84 healthy college students were randomly assigned to either an MRT (n = 53, mean +/- SD: age 25.6 +/- 6.0 years, height 170.1 +/- 8.1 cm, body mass 73.9 +/- 16.0 kg, and body fat 24.6 +/- 8.7%) or WRT (n = 31, mean +/- SD: age 25.5 +/- 5.2 years; height 169.6 +/- 10.1 cm, body mass 75.0 +/- 17.4 kg, and body fat 24.7 +/- 8.5%) group and engaged in a 14-week training program. Each participant's performance was assessed before and immediately after the 14-week training period. Muscular strength was assessed by the one-repetition maximum (1RM) bench press test and the 1RM squat test. Muscular endurance was recorded as the maximum number of repetitions performed with 70% of pretraining 1RM for the bench press and squat exercises. There were no significant differences between the MRT and WRT groups at baseline for muscular strength (p > 0.36) or muscular endurance (p > 0.46). Compared with baseline values, the 14-week training programs produced significant (p < 0.001) improvements in muscular strength and muscular endurance of the MRT and WRT groups. However, no significant difference was observed between the MRT and WRT groups for muscular strength (p > 0.22) or for muscular endurance (p > 0.09) after training. The improvements in muscular strength and muscular endurance after a 14-week MRT program in the present study were similar to those produced by a WRT program, and well-designed MRT exercises seem to be effective for improving muscular fitness.

Effects of manual resistance training on fitness in adolescents.

Manual resistance training (MRT), an alternative to traditional resistance training, requires minimal equipment and may be effective when applied in school-based physical education (PE) classes. The purpose of this study was to document the physical changes in adolescents (n = 222) using MRT in school-based PE settings. Six fitness tests from the Fitnessgram assessment tool were selected to assess students' cardiovascular and muscular fitness, and skinfold tests were used to assess body composition. One control and 2 experimental groups were defined. The control group of students (n = 129) attended regular PE classes. One experimental group (n = 63) attended PE that was complemented by the MRT system. A second experimental group (n = 30) attended PE complemented by MRT and cardiovascular endurance training. With use of the selected Fitnessgram tests, post-test measurements were performed after 9 and 18 weeks of PE. At baseline, there were no significant differences among the 3 groups for most measures. Compared with baseline, the experimental groups improved significantly in all 6 fitness measures and showed more improvements than the control group in most fitness measures both at 9 and 18 weeks. None of the groups showed significant improvement in body composition. The results documented that an MRT-complemented PE program was effective in improving adolescents' muscular fitness. An 18-week combined MRT and cardiovascular endurance training program effectively improved cardiovascular and muscular fitness but was ineffective in improving adolescent body composition. An MRT-based exercise session requires minimal equipment and set-up and can be performed in a short period of time, and therefore it is suitable for application in regular PE settings.

Daily Physical Activity by Occupational Classification in US Adults: NHANES 2005-2006.

BACKGROUND: Little is known about the daily physical activity (PA) levels of people employed in different occupational categories. METHODS: Nine ActiGraph accelerometer-derived daily PA variables are presented and ranked for adults (N = 1465, 20-60 y) working in the 22 occupational categories assessed by NHANES 2005-2006. A composite score was generated for each occupational category by summing the rankings of 3 accelerometer-derived daily PA variables known to have strong associations with health outcomes (total activity counts [TAC], moderate to vigorous PA minutes per week in modified 10-minute bouts [MVPA 10], and percentage of time spent in sedentary activity [SB%]). RESULTS: Classified as high-activity occupational categories, "farming, fishing, forestry," and "building & grounds cleaning, maintenance" occupations had the greatest TAC (461 996 and 449 452), most MVPA 10 (149.6 and 97.8), most steps per day (10 464 and 11 602), and near the lowest SB% (45.2% and 45.4%). "Community, social services" occupations, classified as low-activity occupational categories, had the second lowest TAC (242 085), least MVPA 10 (12.1), fewest steps per day (5684), and near the highest SB% (64.2%). CONCLUSIONS: There is a strong association between occupational category and daily activity levels. Objectively measured daily PA permitted the classification of the 22 different occupational categories into 3 activity groupings.

Pilot study: an acute bout of high intensity interval exercise increases 12.5 h GH secretion.

The purpose of this study was to test the hypothesis that high-intensity interval exercise (HIE) significantly increases growth hormone (GH) secretion to a greater extent than moderate-intensity continuous exercise (MOD) in young women. Five young, sedentary women (mean ± SD; age: 22.6±1.3 years; BMI: 27.4±3.1 kg/m2 ) were tested during the early follicular phase of their menstrual cycle on three occasions. For each visit, participants reported to the laboratory at 1700 h, exercised from 1730-1800 h, and remained in the laboratory until 0700 h the following morning. The exercise component consisted of either 30-min of moderate-intensity continuous cycling at 50% of measured peak power (MOD), four 30-s "all-out" sprints with 4.5 min of active recovery (HIE), or a time-matched sedentary control using a randomized, cross-over design. The overnight GH secretory profile of each trial was determined from 10-min sampling of venous blood from 1730-0600 h, using deconvolution analysis. Deconvolution GH parameters were log transformed prior to statistical analyses. Calculated GH AUC (0-120 min) was significantly greater in HIE than CON (P = 0.04), but HIE was not different from MOD. Total GH secretory rate (ng/mL/12.5 h) was significantly greater in the HIE than the CON (P = 0.05), but MOD was not different from CON or HIE. Nocturnal GH secretion (ng/mL/7.5 h) was not different between the three trials. For these women, in this pilot study, a single bout of HIE was sufficient to increase 12.5 h pulsatile GH secretion. It remains to be determined if regular HIE may contribute to increased daily GH secretion.

Long-distance GM pollen movement of creeping bentgrass using modeled wind trajectory analysis.

The importance of understanding the role of atmospheric conditions in pollen dispersal has grown in recent years with increased field-testing of genetically modified (GM) crop plants. An atmospheric model was used to characterize wind trajectories at 10 m and 100 m above GM pollen source fields located within a 4452-ha "control" area north of Madras, Oregon, USA, designated by the Oregon Department of Agriculture (ODA). The area was used in 2003 for the growth of GM creeping bentgrass (Agrostis stolonifera) engineered to be resistant to glyphosate herbicide. The presence of the GM gene (CP4 EPSPS) provided a distinct selectable marker for pollen-mediated gene flow to sentinel and resident Agrostis spp. plants. Linkage of GM gene presence with wind flow characteristics over the "control" area became essential to understand the timing and processes leading to long-distance transport of this pollen. Wind trajectories showed a general pattern of northwest to southeast air movement. Trajectory travel distances calculated hourly from 06:00 hours to 15:00 hours during the 2003 pollination period (15 June-15 July) showed movement up to 15 km from the "control" area's center by the first hour. Maximum travel distances increased to 40 and 55 km after two and three hours from release, respectively. Calculated wind trajectory positions corresponded with observed long-distance pollen-mediated gene flow in the seedlings of sentinel and resident plants. The highest correlations were found during the late morning hours. Back-calculated wind trajectories from sentinel and resident locations with GM-gene-positive progeny suggested that most successful fertilizations occurred in the direction of prevailing winds during late June 2003. The occurrence of positive progeny from sentinel plants, upwind of the "control" area during this period, indicated the additional influence of local topography on pollen dispersal.

Dynamic gait stability of treadmill versus overground walking in young adults.

Treadmill has been broadly used in laboratory and rehabilitation settings for the purpose of facilitating human locomotion analysis and gait training. The objective of this study was to determine whether dynamic gait stability differs or resembles between the two walking conditions (overground vs. treadmill) among young adults. Fifty-four healthy young adults (age: 23.9±4.7years) participated in this study. Each participant completed five trials of overground walking followed by five trials of treadmill walking at a self-selected speed while their full body kinematics were gathered by a motion capture system. The spatiotemporal gait parameters and dynamic gait stability were compared between the two walking conditions. The results revealed that participants adopted a "cautious gait" on the treadmill compared with over ground in response to the possible inherent challenges to balance imposed by treadmill walking. The cautious gait, which was achieved by walking slower with a shorter step length, less backward leaning trunk, shortened single stance phase, prolonged double stance phase, and more flatfoot landing, ensures the comparable dynamic stability between the two walking conditions. This study could provide insightful information about dynamic gait stability control during treadmill ambulation in young adults.

Effects of cooperative learning strategy on undergraduate kinesiology students' learning styles.

A growing body of research supports cooperative learning as an effective teaching strategy. A specific cooperative learning strategy, Team-based Learning, was applied to a convenience sample of four undergraduate sophomore-level motor behavior courses over four semesters from Fall 2002 to Spring 2004 to examine whether this strategy would affect students' learning styles. The data from the Grasha-Reichmann Student Learning Style Scales indicated that this teaching strategy was associated with a significant decrease in the negative Avoidant and Dependent learning styles and an improvement in the positive Participant learning style.

Controlled whole-body vibration training reduces risk of falls among community-dwelling older adults.

The primary purpose of this study was to systematically examine the effects of an 8-week controlled whole-body vibration training on reducing the risk of falls among community-dwelling adults. Eighteen healthy elderlies received vibration training which was delivered on a side alternating vibration platform in an intermittent way: five repetitions of 1 min vibration followed by a 1 min rest. The vibration frequency and amplitude were 20 Hz and 3.0mm respectively. The same training was repeated 3 times a week, and the entire training lasted for 8 weeks for a total of 24 training sessions. Immediately prior to (or pre-training) and following (or post-training) the 8-week training course, all participants' risk of falls were evaluated in terms of body balance, functional mobility, muscle strength and power, bone density, range of motion at lower limb joints, foot cutaneous sensation level, and fear of falling. Our results revealed that the training was able to improve all fall risk factors examined with moderate to large effect sizes ranging between 0.55 and 1.26. The important findings of this study were that an 8-week vibration training could significantly increase the range of motion of ankle joints on the sagittal plane (6.4° at pre-training evaluation vs. 9.6° at post-training evaluation for dorsiflexion and 45.8° vs. 51.9° for plantar-flexion, p<0.05 for both); reduce the sensation threshold of the foot plantar surface (p<0.05); and lower the fear of falling (12.2 vs. 10.8, p<0.05). These findings could provide guidance to design optimal whole-body vibration training paradigm for fall prevention among older adults.

Comparison of activity monitors to estimate energy cost of treadmill exercise.

PURPOSE: To evaluate the validity of five physical activity monitors available for research: the CSA, the TriTrac-R3D, the RT3, the SenseWear Armband, and the BioTrainer-Pro. METHODS: A total of 10 healthy men and 11 healthy women performed 10 min of treadmill walking at 54, 80, and 107 mxmin and treadmill running at 134, 161, 188, and 214 mxmin. The CSA, TriTrac-R3D, RT3, and BioTrainer-Pro accelerometers were placed side by side bilaterally at the waist in the axillary position, and the SenseWear Armband monitors were placed bilaterally on the posterior portion of each arm in the mid-humeral position. Simultaneous measurements of body motion and indirect calorimetry were continuously recorded during all exercise. Data were analyzed with repeated measures ANOVA and pairwise Bonferroni-adjusted estimated marginal means. RESULTS: : There was no significant difference in the mean energy expenditure (EE) recorded bilaterally by any of the monitors (P < 0.05) at any treadmill speed. The SenseWear Armband, the TriTrac-R3D, and the RT3 had significant increases in mean EE across all walking and running speeds (P < 0.05). Below 161 mxmin, the mean EE recorded by the BioTrainer-Pro and the CSA increased significantly (P < 0.001); however, there was no significant difference (P > 0.10) in mean EE recorded by either monitor for speeds above 161 mxmin. In general, all monitors overestimated EE at most treadmill speeds when compared with indirect calorimetry (P < 0.001), except for the CSA which underestimated EE at the lowest and highest speeds. CONCLUSION: The CSA was the best estimate of total EE at walking and jogging speeds, the TriTrac-R3D was the best estimate of total EE at running speeds, and the SenseWear Armband was the best estimate of total EE at most speeds.

Outcomes of a peer mentor implemented fitness program in older adults: a quasi-randomized controlled trial.

OBJECTIVES: To investigate the effectiveness of different applications of mentoring in an older adult exercise program, this study compared the physical fitness scores, the retention and participation rates of older adults trained by student mentors, peer mentors, peer mentors working independently of the researchers, and a non-exercising control group. METHODS: 106 older adults were recruited and assigned to one of the groups using quasi-randomization. All three experimental groups completed a 14-week intervention. Pre- and post-training assessments of fitness were completed, and retention and participation rates were compared. RESULTS: High retention and participation rates, as well as significant improvements in fitness scores from baseline to post-test were observed in all three mentored groups. While the control group showed improvement only in one fitness test, subjects in the mentored groups improved similarly in all measures, regardless of the type of mentoring received. DISCUSSION: These findings indicated effectiveness of the peer mentor model and suggested that with adequate preparation peer mentors may be capable of guiding older adult participants effectively without assistance from professional staff.

Potential for metal contamination by direct sonication of nanoparticle suspensions.

While conducting toxicity tests with nano titanium dioxide, the authors found that test suspensions were being contaminated with aluminum and titanium from tip erosion during direct sonication. The contaminating alloy particles had a measurable size distribution and zeta potential using dynamic light scattering, which changed the measured characteristics of the suspensions. Caution should be used when employing direct sonication for preparing test suspensions due to potential interferences of these particles in toxicological assessments.