Effects of pubertal growth variation on knee mechanics during walking in female and male adolescents.

INTRODUCTION: Puberty substantially alters the body's mechanical properties, neuromuscular control, and sex differences therein, likely contributing to increased, sex-biased knee injury risk during adolescence. Female adolescents have higher risk for knee injuries than male adolescents of similar age engaging in similar physical activities, and much research has investigated sex differences in mechanical risk factors. However, few studies address the considerable variation in pubertal growth (timing, pace), knee mechanics, and injury susceptibility within sexes, or the impact of such growth variation on mechanical injury risk. OBJECTIVES: The present study tested for effects of variation in pubertal growth on established mechanical knee injury risk factors, examining relationships between and within sexes. METHODS: Pubertal growth indices describing variation in the timing and rate of pubertal growth were developed using principal component analysis and auxological data from serial stature measurements. Linear mixed models were applied to evaluate relationships between these indices and knee mechanics during walking in a sample of adolescents. RESULTS: Later developing female adolescents with slower pubertal growth had higher extension moments throughout stance, whereas earlier developers had higher valgus knee angles and moments. In male adolescents, faster and later growth were related to higher extension moments throughout gait. In both sexes, faster growers had higher internal rotation moments at foot-strike. CONCLUSIONS: Pubertal growth variation has important effects on mechanical knee injury risk in adolescence, affecting females and males differently. Earlier developing females exhibit greater injury risk via frontal plane factors, whereas later/faster developing males have elevated risk via sagittal plane mechanisms.

Family satisfaction in a neuro trauma ICU.

OBJECTIVE: The purpose of this quality improvement initiative was to evaluate satisfaction of family members of patients in a neuro trauma ICU (NTICU). METHODS: Adult patients (age 18+) admitted to the NTICU for at least 24 hours between June 2017 and November 2018 were identified. Near or at the time of discharge from the NTICU, the health unit coordinator or registered nurse identified the family member who was either the next-of-kin, surrogate decision-maker, or person who had been most frequently present at the patient's bedside. This person was provided a packet containing a letter of consent and the Critical Care Family Satisfaction Survey (CCFSS). RESULTS: Surveys were completed by 78 family members, the majority of whom were the wife of the patient (n = 35, 44%), 60 years and older (n = 48, 60.8%). Fifty-seven percent of patients (n = 45) were in the ICU less than 3 days and 59% (n = 47) of medical events were injury-related. Total CCFSS scores ranged from 69 to 100 (median 95). The item with the largest number of dissatisfied responses was "Noise level in the critical care unit" (n = 4, 5.3% not satisfied). Open-ended question comments were primarily positive (n = 60, 66%), with 32% (n = 29) representing areas for improvement. CONCLUSIONS: Results of this satisfaction survey have been disseminated to leadership and have been taken into consideration in the planning of a new hospital building currently being built, including ICU patient rooms that allow for more privacy and reduced noise, and more comfortable family rooms. RELEVANCE TO CLINICAL PRACTICE: Family members are a very useful source of feedback for ICU care. Several concerns identified by family members in this study are likely to be relevant to other sites. These included: communication between health care providers and family about patient status, noise in the ICU, peaceful waiting areas for family, and slow transfers.

A Multisite Quality Improvement Project to Standardize the Assessment of Pressure Ulcer Healing in Veterans with Spinal Cord Injuries/Disorders.

OBJECTIVE: The objective was to implement the evidence-based Spinal Cord Impairment Pressure Ulcer Monitoring Tool (SCI-PUMT) in 23 Spinal Cord Injury/Disorders Centers (SCI/D) in the Veterans Health Administration (VHA). SETTING: A collaborative was held in Minnesota that was attended by key personnel from SCI/D Centers in the VHA. METHODS: This initiative was based on a 3-year longitudinal study that established the validity and reliability of a novel pressure ulcer monitoring tool for persons with spinal cord impairment. A multifaceted evidence-based strategy was used to implement the Institute for Healthcare Improvement's framework of Plan-Do-Study-Act. The plan was executed by clinical champions who implemented the tool in their respective SCI/D Centers following a conference that used both didactic and practicum approaches. OUTCOMES: A 15-item toolkit was developed to educate clinicians and patients regarding use of the SCI-PUMT. Toolkit elements were frequently accessed over the VA intranet (n = 3254). The 1.5-day national conference rolled out the new tool to the SCI/D Centers. Pre/post SCI-PUMT knowledge of the SCI-PUMT improved by 78% during the conference. Following the conference, periodic conference calls cemented the implementation efforts of the SCI-PUMT clinical champions and barriers were mitigated.

Increasing Adolescent Sexual Activity Screening Through a Provider-Based Intervention.

Screening for adolescent sexual activity is a vital aspect of comprehensive pediatric care. Adolescents engage in risky sexual behaviors. Thus, a complete and accurate sexual health history can assist in the prevention and treatment of disease, prevention of unwanted pregnancy, treatment of existing diseases, and optimal planning of future healthcare for adolescents. Current evidence shows that provider-focused strategies improve the delivery of preventive services, including sexual health screenings. In this initiative, we assessed and examined pre- and post-screening rates for sexual activity among adolescents by advanced practice providers. This multi-site initiative was implemented in four school-based health centers and a school-linked center that included 2,102 unique patients ages 9 to 24 years. Our biphasic intervention included education for advanced practice providers and electronic health record modifications. Pre- and post-data collection was conducted to determine changes in the rate of screening for sexual activity during a primary care adolescent health visit over a 3-year period. Data were collected via retrospective medical chart review and analyzed in three time periods for comparison from 2018 to 2021. Screening rates for sexual activity increased significantly after the intervention (all p < .001) with the likelihood more than double that of the year before it was implemented. The intervention was deemed to be a feasible and cost-effective strategy to improve the provider's willingness and ability to provide more adolescent sexual health screenings.

Maximizing the Potential of Air National Guard International Health Specialists for Global Health Engagement.

The Air Force International Health Specialist program provides expert medical and public health support to enhance global health engagement efforts. National Guardsmen possess unique civilian health care expertise to support global health engagement. The DoD must increase support for Air National Guard International Health Specialist involvement, including training and development opportunities.

Tripogon loliiformis tolerates rapid desiccation after metabolic and transcriptional priming during initial drying.

Crop plants and undomesticated resilient species employ different strategies to regulate their energy resources and growth. Most crop species are sensitive to stress and prioritise rapid growth to maximise yield or biomass production. In contrast, resilient plants grow slowly, are small, and allocate their resources for survival in challenging environments. One small group of plants, termed resurrection plants, survive desiccation of their vegetative tissue and regain full metabolic activity upon watering. However, the precise molecular mechanisms underlying this extreme tolerance remain unknown. In this study, we employed a transcriptomics and metabolomics approach, to investigate the mechanisms of desiccation tolerance in Tripogon loliiformis, a modified desiccation-tolerant plant, that survives gradual but not rapid drying. We show that T. loliiformis can survive rapid desiccation if it is gradually dried to 60% relative water content (RWC). Furthermore, the gene expression data showed that T. loliiformis is genetically predisposed for desiccation in the hydrated state, as evidenced by the accumulation of MYB, NAC, bZIP, WRKY transcription factors along with the phytohormones, abscisic acid, salicylic acid, amino acids (e.g., proline) and TCA cycle sugars during initial drying. Through network analysis of co-expressed genes, we observed differential responses to desiccation between T. loliiformis shoots and roots. Dehydrating shoots displayed global transcriptional changes across broad functional categories, although no enrichment was observed during drying. In contrast, dehydrating roots showed distinct network changes with the most significant differences occurring at 40% RWC. The cumulative effects of the early stress responses may indicate the minimum requirements of desiccation tolerance and enable T. loliiformis to survive rapid drying. These findings potentially hold promise for identifying biotechnological solutions aimed at developing drought-tolerant crops without growth and yield penalties.

Evaluation of Protective Properties of Commercially Available Medical Helmets: Are Medical Helmets Protective?

OBJECTIVES: The aims of the study were to evaluate and to compare protective properties of commercially available medical helmets for a set of standardized head injury risk measures. METHODS: Eleven helmet types were evaluated to represent the variety of commercially available medical helmet designs and manufacturers. A test mannequin and sensor apparatus were used to simulate a backward-standing fall. The head/neck size, mass, and "standing" height of the mannequin (5'9″) were representative of a 50th percentile male. A triaxial array was placed at the head center of mass to position 3 linear accelerometers and 3 angular rate sensors. Data were collected for 5 single trials for each helmet, as well as 5 repeated trials. Five trials were also collected with no helmet scenarios. Three head injury risk measures were examined (linear acceleration, angular acceleration, and head injury criterion). Data were analyzed by clinical cutoff thresholds and continuous values. RESULTS: Helmets varied in their performance across head injury risk measures. All helmets provided higher levels of protection compared with no helmet scenarios. No helmets were protective for subdural hematoma (measured by angular acceleration). All helmets lost protective properties with repeated falls. Results for skull fracture risk were inconsistent between linear acceleration and head injury criterion injury risk measures. CONCLUSIONS: No helmets were protective across all head injury risk measures. Medical helmets may reduce some fall injury severity but may not prevent all types of head injury. All helmets exhibited worsening of protective properties with repeated falls. We recommend medical helmets be replaced after each fall incident where the helmet impacts another surface.

An innovative interprofessional education simulation for athletic training and prelicensure nursing students: Development, implementation, and student perspectives.

BACKGROUND: The purpose of this article is to describe the development, implementation, and evaluation of a Simulation Interprofessional Education (Sim-IPE) activity for healthcare students from different disciplines (athletic training [AT] and nursing). The objective for the Sim-IPE activity was to engage AT and prelicensure nursing students in a realistic healthcare scenario to enhance knowledge about one another's profession, develop interprofessional skills, collaborate with one another, and communicate effectively as a team as they performed care. METHODS: This mixed methods study employed a one-time posttest design for a convenience sample of AT and prelicensure nursing students following a simulation intervention. Students completed the Student Perceptions of Interprofessional Clinical Education-Revised (SPICE-R) survey and answered open-ended response questions. RESULTS: Thirteen students (N = 13) from Cohort 1 and 12 students (N = 12) from Cohort 2 completed the SPICE-R survey. Most students strongly agreed/agreed for each of the SPICE-R survey questions. Qualitative findings indicated the students positively perceived the Sim-IPE activity as it helped them discover the value of interprofessional patient care. DISCUSSION: The quantitative findings indicated that the students found the Sim-IPE an effective learning methodology to achieve the objectives while the qualitative findings gave further insight into the students' perceptions of interprofessional teamwork and the value of the prebrief session conducted before the simulation. The findings will inform future Sim-IPE activities involving additional groups of healthcare students.

Development, Validity, and Reliability of a Novel Walking Speed Measurement Device: the GaitBox.

BACKGROUND: Gait speed is an important measure of health status for older adults and individuals with neurological conditions. Literature reports that measurements made by people are not as accurate as automatic timers. RESEARCH QUESTION: Is the GaitBox (GB), a device to measure walking speed (WS) automatically and accurately, a valid approach to walking speed measurement in a clinical setting? METHODS: Two prospective validation studies were completed comparing the GB to human timers (HT) and the Sprint Timing System (STS). Subjects were recruited from convenience samples of healthy older adults (S1, N = 35, 72.4 + 7.4 years of age) and individuals with Spinal Cord Injury (SCI), Traumatic Brain Injury (TBI), or unknown / no diagnosis (S2, N = 44, 35.3 + 13.5 years of age). Subjects completed 4 timed walks. The GB, HT, and STS simultaneously measured WS across a 4 m or 10 m course. Protocol followed an adapted version of the NIH Walk Test. Subjects were instructed to walk at a normal pace. Validity and reliability were determined using Pearson correlations, absolute mean differences, Intraclass Correlation Coefficients (ICC's) and Bland-Altman plots. RESULTS: WS measured in both studies demonstrated strong correlations between GB and STS (r = 0.98-0.99, p < 0.0001), excellent test-retest reliability GB ICC's (0.93-0.94), no systematic bias, and good precision. In S1 and S2, ICC's between GB and STS were excellent at 0.91 and 0.93, respectively. SIGNIFICANCE: Considering the increased use of WS as a clinically relevant measure of mobility, functional decline, and recovery, accurate measurement of WS are important. These studies show the GB is a valid and reliable measurement tool within various populations completing the 4 m and 10 m walk tests at a usual speed. Additional populations and walking distances should be evaluated further. Due to its accuracy, the GaitBox is a valid alternative to HT in the clinic setting.

Deciphering the microbial and molecular responses of geographically diverse Setaria accessions grown in a nutrient-poor soil.

The microbial and molecular characterization of the ectorhizosphere is an important step towards developing a more complete understanding of how the cultivation of biofuel crops can be undertaken in nutrient poor environments. The ectorhizosphere of Setaria is of particular interest because the plant component of this plant-microbe system is an important agricultural grain crop and a model for biofuel grasses. Importantly, Setaria lends itself to high throughput molecular studies. As such, we have identified important intra- and interspecific microbial and molecular differences in the ectorhizospheres of three geographically distant Setaria italica accessions and their wild ancestor S. viridis. All were grown in a nutrient-poor soil with and without nutrient addition. To assess the contrasting impact of nutrient deficiency observed for two S. italica accessions, we quantitatively evaluated differences in soil organic matter, microbial community, and metabolite profiles. Together, these measurements suggest that rhizosphere priming differs with Setaria accession, which comes from alterations in microbial community abundances, specifically Actinobacteria and Proteobacteria populations. When globally comparing the metabolomic response of Setaria to nutrient addition, plants produced distinctly different metabolic profiles in the leaves and roots. With nutrient addition, increases of nitrogen containing metabolites were significantly higher in plant leaves and roots along with significant increases in tyrosine derived alkaloids, serotonin, and synephrine. Glycerol was also found to be significantly increased in the leaves as well as the ectorhizosphere. These differences provide insight into how C4 grasses adapt to changing nutrient availability in soils or with contrasting fertilization schemas. Gained knowledge could then be utilized in plant enhancement and bioengineering efforts to produce plants with superior traits when grown in nutrient poor soils.

Effects of turning on skin-bed interface pressures in healthy adults.

AIM: This paper is a report of a study of the effects of lateral turning on skin-bed interface pressures in the sacral, trochanteric and buttock regions, and its effectiveness in unloading at-risk tissue. BACKGROUND: Minimizing skin-support surface interface pressure is important in pressure ulcer prevention, but the effect of standard patient repositioning on skin interface pressure has not been objectively established. METHODS: Data were collected from 15 healthy adults from a university-affiliated hospital. Mapped 24-inch x 24-inch (2304 half-inch sensors) interface pressure profiles were obtained in the supine position, followed by lateral turning with pillow or wedge support and subsequent head-of-bed elevation to 30 degrees . RESULTS: Raising the head-of-bed to 30 degrees in the lateral position statistically significantly increased peak interface pressures and total area > or = 32 mmHg. Comparing areas > or = 32 mmHg from all positions, 93% of participants had skin areas with interface pressures > or = 32 mmHg throughout all positions (60 +/- 54 cm(2)), termed 'triple jeopardy areas'. The triple jeopardy area increased statistically significantly with wedges as compared to pillows (153 +/- 99 cm(2) vs. 48 +/- 47 cm(2), P < 0.05). CONCLUSION: Standard turning by experienced intensive care unit nurses does not reliably unload all areas of high skin-bed interface pressures. These areas remain at risk for skin breakdown, and help to explain why pressure ulcers occur despite the implementation of standard preventive measures. Support materials for maintaining lateral turned positions can also influence tissue unloading and triple jeopardy areas.

An Exploratory Analysis of Potential New Biomarkers of Cognitive Function.

We examined the relationship between serially measured, novel serum biomarkers and a measure of cognitive functioning in older adults. We assayed stored serum samples from two Fels Longitudinal Study visits in N = 100 adult participants (visit 1 ages 59.3 ± 8.5 years; 53% female), and Montreal Cognitive Assessment (MoCA) scores also assessed at the second visit. Assays included acylcarnitines, amino acids, and 2-hydroxybutyric acid (b-HBA). Cross-sectional correlations between acylcarnitines and amino acids and MoCA were identified. Serial change in short-chain acylcarnitines and visit 2 MoCA were also correlated. Participants with MoCA scores <26 were more likely to have an increase in short-chain acylcarnitines between visits 1 and 2 [adjusted odds ratio (OR) = 5.24; 95% confidence interval (CI) 1.07-25.9]. b-HBA was also correlated with acylcarnitines. Several cross-sectional and serial associations between novel serum biomarkers and cognitive functioning were identified. b-HBA may also be a cost-effective marker of dysregulation associated with cognitive decline.

The Risk Factors of Performance-Based Early Frailty in Midlife and Older Age.

Background: Identifying impairments prior to onset of physical frailty may inform targeted interventions. An objective, clinically feasible early frailty measure, termed performance-based early frailty (PBEF) was developed, and antecedent and current risk factors were examined. Method: Data were from N = 104 participants of the Fels Longitudinal Study. PBEF was derived from age-specific cut points for time to complete five chair stands and walk four meters. "Pre-PBEF" and "PBEF" were defined as impairment in one or both measures, respectively. Candidate PBEF risk factors included body composition, health and quality of life, grip strength, and biomarker measures. Results: Pre-PBEF was identified in 26% and 30% of midlife and older adults, and PBEF was identified in 11% and 14% of midlife and older adults, respectively. When predicting midlife PBEF, only current physical activity was significant (odds ratio [OR] = 0.18). In older adults, PBEF status was predicted by previous heavier drinking (OR = 3.09), previous better grip strength (OR = 0.92), current poorer sleep habits (OR = 1.19), and current higher C-reactive protein concentrations (OR = 1.20). Conclusion: Differing age group patterns of predictors emerged, suggesting that PBEF in midlife is likely a state influenced by current health status, whereas older age PBEF is influenced by both current and antecedent factors.

Economic Analysis of Primary Care-Based Physical Activity Counseling in Older Men: The VA-LIFE Trial.

OBJECTIVES: To perform an economic evaluation of a primary care-based physical activity counseling intervention that improved physical activity levels and rapid gait speed in older veterans. DESIGN: Secondary objective of randomized trial that assessed the effect of exercise counseling (relative to usual care) on physical performance, physical activity, function, disability, and medical resource use and cost. SETTING: Veterans Affairs Medical Center, Durham, North Carolina. PARTICIPANTS: Male veterans aged ≥70 years (n = 398). INTERVENTION: An experienced health counselor provided baseline in-person exercise counseling, followed by telephone counseling at 2, 4, and 6 weeks, and monthly thereafter through one year. Each participant's primary care physician provided initial endorsement of the intervention, followed by monthly automated telephone messages tailored to the patient. Individualized progress reports were mailed quarterly. MEASUREMENTS: Intervention costs were assessed. Health care resource use and costs were estimated from enrollment through one year follow-up. The incremental cost of achieving clinically significant changes in major trial endpoints was calculated. RESULTS: The total direct cost of the intervention per participant was $459, 85% of which was counselor effort. With overhead, program cost totaled $696 per participant. Medical costs during follow-up reached $10,418 with the intervention, versus $12,052 with usual care (difference = -$1,634 (95% confidence interval = -$4,683 to $1,416; P = .29)). Expressed in terms of short-term clinical outcomes, the intervention cost $4,971 per additional patient reaching target exercise levels, or $4,640 per patient achieving a clinically significant change in rapid gait speed. CONCLUSION: Improvements in physical activity and rapid gait speed in the physical activity counseling group were obtained at a cost that represents a small fraction of patients' annual health care costs.

A Novel Analytic Technique to Measure Associations Between Circulating Biomarkers and Physical Performance Across the Adult Life Span.

Understanding associations between circulating biomarkers and physical performance across the adult life span could aid in better describing mechanistic pathways leading to disability. We hypothesized that high concentrations of circulating biomarkers would be associated with lower functioning across study populations representing the adult life span. The data were from four intervention and two observational studies with ages ranging 22-89 years. Biomarkers assayed included inflammatory, coagulation, and endothelial function markers. Physical performance was measured either by VO2peak (studies of young and middle-aged adults) or usual gait speed (studies of older adults). Partialled (by age, body mass index, race, and sex) and weighted common correlations were calculated between biomarkers and physical performance. Homogeneity of the associations was also assessed. Interleukin-6 (weighted r = -.22), tumor necrosis factor receptor 2 (weighted r = -.19), D-dimer (weighted r = -.16), tumor necrosis factor receptor 1 (weighted r = -.15), granulocyte colony-stimulating factor (weighted r = -.14), and tumor necrosis factor alpha (weighted r = -.10) were all significantly inversely correlated with physical performance (p < .05). All significant correlations were homogeneous across studies. In summary, we observed consistent inverse associations between six circulating biomarkers and objective measures of physical performance. These results suggest that these serum biomarkers may be broadly applicable for detection, trajectory, and treatment monitoring of physical function across the life span or possibly for midlife predictors of functionally deleterious conditions.

Association of traumatic brain injury with subsequent neurological and psychiatric disease: a meta-analysis.

OBJECTIVE: Mild traumatic brain injury (TBI) has been proposed as a risk factor for the development of Alzheimer's disease, Parkinson's disease, depression, and other illnesses. This study's objective was to determine the association of prior mild TBI with the subsequent diagnosis (that is, at least 1 year postinjury) of neurological or psychiatric disease. METHODS: All studies from January 1995 to February 2012 reporting TBI as a risk factor for diagnoses of interest were identified by searching PubMed, study references, and review articles. Reviewers abstracted the data and assessed study designs and characteristics. RESULTS: Fifty-seven studies met the inclusion criteria. A random effects meta-analysis revealed a significant association of prior TBI with subsequent neurological and psychiatric diagnoses. The pooled odds ratio (OR) for the development of any illness subsequent to prior TBI was 1.67 (95% CI 1.44-1.93, p < 0.0001). Prior TBI was independently associated with both neurological (OR 1.55, 95% CI 1.31-1.83, p < 0.0001) and psychiatric (OR 2.00, 95% CI 1.50-2.66, p < 0.0001) outcomes. Analyses of individual diagnoses revealed higher odds of Alzheimer's disease, Parkinson's disease, mild cognitive impairment, depression, mixed affective disorders, and bipolar disorder in individuals with previous TBI as compared to those without TBI. This association was present when examining only studies of mild TBI and when considering the influence of study design and characteristics. Analysis of a subset of studies demonstrated no evidence that multiple TBIs were associated with higher odds of disease than a single TBI. CONCLUSIONS: History of TBI, including mild TBI, is associated with the development of neurological and psychiatric illness. This finding indicates that either TBI is a risk factor for heterogeneous pathological processes or that TBI may contribute to a common pathological mechanism.

Pressure ulcer risk of patient handling sling use.

Patient handling slings and lifts reduce the risk of musculoskeletal injuries for healthcare providers. However, no published evidence exists of their safety with respect to pressure ulceration for vulnerable populations, specifically persons with spinal cord injury, nor do any studies compare slings for pressure distribution. High-resolution interface pressure mapping was used to describe and quantify risks associated with pressure ulceration due to normal forces and identify at-risk anatomical locations. We evaluated 23 patient handling slings with 4 nondisabled adults. Sling-participant interface pressures were recorded while participants lay supine on a hospital bed and while suspended during typical patient transfers. Sling-participant interface pressures were greatest while suspended for all seated and supine slings and exceeded 200 mm Hg for all seated slings. Interface pressures were greatest along the sling seams (edges), regardless of position or sling type. The anatomical areas most at risk while participants were suspended in seated slings were the posterior upper and lower thighs. For supine slings, the perisacral area, ischial tuberosities, and greater trochanters were most at risk. The duration of time spent in slings, especially while suspended, should be limited.

Differences between completely physically inactive and low active older men and their response to an exercise intervention: the Veterans LIFE study.

BACKGROUND: Physical activity interventions typically do not report behavioral changes in activity sub-groups. The aim of this study was to compare baseline differences and changes in physical activity between truly physically inactive men and low active men enrolled in a twelve-month, home-based physical activity intervention. METHODS: Veterans with a mean age of 77.6 years were randomized to either a physical activity intervention or usual care. Measures included self-reported physical activity, physical function, and physical performance. RESULTS: At baseline, the physically inactive group reported more symptoms and poorer functioning than the low active group. At 12 months, physically inactive men randomized to the intervention group increased their physical activity to an average of 73.3 minutes per week. Physically inactive individuals randomized to the control group were eight times more likely to remain inactive compared to the low active group. CONCLUSIONS: Completely physically inactive older men can markedly increase physical activity levels with a long-term intervention. Without such intervention, the likelihood of this group remaining inactive is eightfold.

Development and validation of skinfold-thickness prediction equations with a 4-compartment model.

BACKGROUND: Skinfold-thickness measurements are commonly obtained for the indirect assessment of body composition. OBJECTIVE: We developed new skinfold-thickness equations by using a 4-compartment model as the reference. Additionally, we compared our new equations with the Durnin and Womersley and Jackson and Pollock skinfold-thickness equations to evaluate each equation's validity and precision. DESIGN: Data from 681 healthy, white adults were used. Percentage body fat (%BF) values were calculated by using the 4-compartment model. The cohort was then divided into validation and cross-validation groups. Equations were developed by using regression analyses and the 4-compartment model. All equations were then tested by using the cross-validation group. Tests for accuracy included mean differences, R(2), and Bland-Altman plots. Precision was evaluated by comparing root mean squared errors. RESULTS: Our new equations' estimated means for %BF in men and women (22.7% and 32.6%, respectively) were closest to the corresponding 4-compartment values (22.8% and 32.8%). The Durnin and Womersley equation means in men and women (20.0% and 31.0%, respectively) and the Jackson and Pollock mean in women (26.2%) underestimated %BF. All equations showed a tendency toward underestimation in subjects with higher %BF. Bland-Altman plots showed limited agreement between Durnin and Wormersley, Jackson and Pollock, and the 4-compartment model. Precision was similar among all the equations. CONCLUSIONS: We developed accurate and precise skinfold-thickness equations by using a 4-compartment model as the method of reference. Additionally, we found that the skinfold-thickness equations frequently used by clinicians and practitioners underestimate %BF.

Accuracy of VO2(max) prediction equations in older adults.

PURPOSE: We explored the accuracy and bias of prediction equations (ACSM and Foster) in older, deconditioned men and women. We also examined the predictors of VO2(max) to further understand which variables affect respiratory fitness in the elderly. METHODS: One hundred seventy-one community dwelling, men (72.6 +/- 4.8 yr) and women (71.0 +/- 5.1 yr) screened in a clinical trial were retrospectively examined. VO2(max) was measured using a standardized protocol with gas exchange measured. Measured VO2 (max) values were compared with prediction equations via mean difference analyses, and bias was explored using Bland-Altman analyses. Regression analysis determined significant predictors of measured VO2 (max). Alpha was P