Trabecular bone score and its association with Cobb angle kyphosis in older men: a cross-sectional study for the Osteoporotic Fractures in Men (MrOS) Study.

Hyperkyphosis (HK), or accentuated forward spinal curvature, commonly affects older people, although its causes are not completely understood. We tested whether a measure of bone quality, trabecular bone score (TBS), is associated with HK in 1997 older men, and determined that men with degraded TBS were more likely to have HK. INTRODUCTION: While vertebral fractures and low bone mineral density (BMD) contribute to kyphosis progression, it is unknown whether the trabecular bone score (TBS) may provide additional information on bone quality that could influence the degree of kyphosis. We hypothesized that degraded TBS would be associated with hyperkyphosis (HK) defined as a Cobb angle > 50°. METHODS: Using data from 1997 participants of the Osteoporotic Fractures in Men (MrOS) Study who had baseline TBS and Cobb angle kyphosis measured, we investigated whether men with degraded TBS were more likely to be hyperkyphotic, even after adjustment for BMD and prevalent vertebral fractures. RESULTS: Men were an average age of 74 ± 6 (mean ± SD) years with a mean kyphosis angle of 38.6 ± 11.5°, 295 (15%) were classified as hyperkyphotic, and 416 (21%) had degraded TBS. Compared with men with TBS > 1.2, men with degraded TBS were more likely to have HK (OR: 1.47, 95% CI: 1.06-2.06, p = 0.02) after adjusting for age, clinic, race, BMI, hip BMD, and prevalent vertebral fracture. If spine instead of hip BMD was included in the model, the odds ratio decreased to 1.35 (95% CI: 0.97-1.89, p = 0.08). CONCLUSIONS: Older men with degraded TBS are more likely to have HK not explained by underlying vertebral fractures.

Kyphosis and 3-year fall risk in community-dwelling older men.

Hyperkyhosis is thought to be a fall risk factor in older adults. This large study of older men found that fall risk increased with greater kyphosis measured with the blocks method, but did not find an association between kyphosis and falls when measured by the commonly used the Cobb angle method. INTRODUCTION: Research suggests an association between hyperkyphosis and falls in community-dwelling older adults, though this has not been investigated within large, population-based studies. This study sought to determine whether two measures of kyphosis prospectively predict fall risk over 3 years among older men. METHODS: Within the Osteoporotic Fractures in Men Study (MrOS), we conducted two 3-year prospective studies of 2346 and 2928 men. The first group had kyphosis measured by the Cobb angle at visit 1, while the second group had kyphosis assessed with the blocks method at visit 3; both groups then self-reported falls tri-annually for 3 years. Poisson regression with GEE was used to obtain relative risks (RR) of falls. RESULTS: The fall rates over 3 years were 651/1000 person-years among the visit 1 sample (mean age 74 ± 6 years) and 839/1000 person-years among the visit 3 sample (mean age 79 ± 5 years). In adjusted models of the visit 3 sample, the risk of falls was increased by 12% for each standard deviation increase (1.4 blocks) in the number of blocks required to achieve a neutral head and neck position (RR = 1.12, 95% CI = 1.06, 1.18). The Cobb angle was not associated with falls in the visit 1 sample. CONCLUSIONS: Although the Cobb angle did not predict falls in community-dwelling older men over 3 years, the blocks method of measuring kyphosis was predictive of falls in this population. This difference could be due to the Cobb angle's focus on thoracic kyphosis, whereas the blocks method may additionally capture abnormal cervical spine curvature.

Kyphosis and incident falls among community-dwelling older adults.

Hyperkyphosis commonly affects older persons and is associated with morbidity and mortality. Many have hypothesized that hyperkyphosis increases fall risk. Within this prospective study of older adults, kyphosis was significantly associated with incident falls over 1 year. Measures of hyperkyphosis could enhance falls risk assessments during primary care office visits. INTRODUCTION: To determine the association between four measures of kyphosis and incident and injurious falls in older persons. METHODS: Community-dwelling adults aged 65 and older (n = 72) residing in southern California were invited to participate in a prospective cohort study. Participants had kyphosis assessed four ways. Two standing measures included a flexicurve ruler placed against the back to derive a kyphotic index and the Debrunner kyphometer, a protractor used to measure the kyphotic angle in degrees. Two lying measures included the blocks method (number of 1.7 cm blocks needed to achieve a neutral head position while lying supine) and traditional Cobb angle calculation derived from DXA based lateral vertebral assessment. Baseline demographic, clinical, and other health information (including a timed up and go (TUG) test) were assessed at a clinic visit. Participants were followed monthly through email or postcard for 1 year, with falls outcomes confirmed through telephone interview. RESULTS: Mean age was 77.8 (± 7.1) among the 52 women and 20 men. Over 12 months, 64% of participants experienced at least one incident fall and 35% experienced an injurious fall. Each standard deviation increase in kyphosis resulted in more than doubling the adjusted odds of an incident fall, even after adjusting for TUG. Odds of injurious falls were less consistent across measures; after adjusting for TUG, only the blocks method was associated with injurious falls. CONCLUSIONS: Each kyphosis measure was independently associated with incident falls. Findings were inconsistent for injurious falls; the blocks measure suggested the strongest association. If these findings are replicated, the blocks measure could be incorporated into office visits as a quick and efficient tool to identify patients at increased fall risk.

The effect of age on fitness among female firefighters.

BACKGROUND: The physical demands of firefighting require both cardiovascular and muscular fitness, which both decline with age. While much has been published on age-related changes among male firefighters (FFs), data on female FFs are lacking. AIMS: To describe cardiorespiratory fitness (CRF) and muscular fitness in a sample of female career FFs ranging in age from 25 to 60 years and determine whether ageing affects their achievement of the current recommended professional CRF standards of 12 metabolic equivalents (METs). METHODS: Data were collected on female FFs over an 11-year period. A cross-sectional analysis using one-way analysis of variance with Bonferroni post hoc comparisons was used to compare age groups. RESULTS: There were 96 study participants. Maximum METs was significantly higher (P < 0.01) in the 25- to 34-year age group (14.6 ± 2.1) compared with the 35-44 age group (12.9 ± 2.0 METs) and the 45-54 age group (12.2 ± 1.8 METs, P < 0.001). While the mean values of all measured age groups met or exceeded the 12-MET profession standard, as many as one-third of FFs <45 years of age and 43% of FFs >45 years of age fell below the benchmark of 12 METs. Muscular fitness as measured by maximum number of push-ups, sit-ups and back endurance was not significantly different between age groups. CONCLUSIONS: Fire departments should recognize and take steps to ensure all female FFs maintain CRF and muscular fitness throughout their careers.

Trunk lean mass and its association with 4 different measures of thoracic kyphosis in older community dwelling persons.

BACKGROUND: The causes of age-related hyperkyphosis (HK) include osteoporosis, but only 1/3 of those most severely affected have vertebral fractures, suggesting that there are other important, and potentially modifiable causes. We hypothesized that muscle mass and quality may be important determinants of kyphosis in older persons. METHODS: We recruited 72 persons >65 years to participate in a prospective study designed to evaluate kyphosis and fall risk. At the baseline visit, participants had their body composition measures completed using Dual Energy X-ray Absorptiometry (DXA). They had kyphosis measured in either the standing [S] or lying [L] position: 1) Cobb angle from DXA [L]; 2) Debrunner kyphometer [S]; 3) architect's flexicurve ruler [S]; and 4) blocks method [L]. Multivariable linear/logistic regression analyses were done to assess the association between each body composition and 4 kyphosis measures. RESULTS: Women (n = 52) were an average age of 76.8 (SD 6.7) and men 80.5 (SD 7.8) years. They reported overall good/excellent health (93%), the average body mass index was 25.3 (SD 4.6) and 35% reported a fall in the past year. Using published cut-offs, about 20-30% were determined to have HK. For the standing assessments of kyphosis only, after adjusting for age, sex, weight and hip BMD, persons with lower TLM were more likely to be hyperkyphotic. CONCLUSIONS: Lower TLM is associated with HK in older persons. The results were stronger when standing measures of kyphosis were used, suggesting that the effects of muscle on thoracic kyphosis are best appreciated under spinal loading conditions.

Associations between physical activity and BMI, body fatness, and visceral adiposity in overweight or obese Latino and non-Latino adults.

BACKGROUND/OBJECTIVES: Although several studies have reported associations between moderate to vigorous physical activity (MVPA), body fatness and visceral adipose tissue (VAT), the extent to which associations differ among Latinos and non-Latinos remains unclear. This study evaluated the associations between body composition and MVPA in Latino and non-Latino adults. SUBJECTS/METHODS: An exploratory, cross-sectional analysis was conducted using baseline data collected from 298 overweight adults enrolled in a 12-month randomized controlled trial that tested the efficacy of text messaging to improve weight loss. MVPA, body fatness and VAT were assessed by waist-worn accelerometry, dual-energy x-ray absorptiometry (DXA), and DXA-derived software (GE CoreScan GE, Madison, WI, USA), respectively. Participants with <5 days of accelerometry data or missing DXA data were excluded; 236 participants had complete data. Multivariable linear regression assessed associations between body composition and MVPA per day, defined as time in MVPA, bouts of MVPA (time per bout ⩾10 min), non-bouts of MVPA (time per bout <10 min) and meeting the 150-min MVPA guideline. The modifying influence of ethnicity was modeled with a multiplicative interaction term. RESULTS: The interaction between ethnicity and MVPA in predicting percent body fat was significant (P=0.01, 95% confidence interval (CI) (0.58, 4.43)) such that a given increase in MVPA was associated with a greater decline in total body fat in non-Latinos compared with Latinos (adjusted for age, sex and accelerometer wear time). There was no interaction between ethnicity and MVPA in predicting VAT (g) (P=0.78, 95% CI (-205.74, 273.17)) and body mass index (BMI) (P=0.18, 95% CI (-0.49, 2.26)). CONCLUSIONS: An increase in MVPA was associated with a larger decrease in body fat, but neither BMI nor VAT, in non-Latinos compared with Latinos. This suggests that changes in VAT and BMI in response to MVPA may be less influenced by ethnicity than is total body fatness.

Factors Associated with Visceral Fat Loss in Response to a Multifaceted Weight Loss Intervention.

BACKGROUND: Visceral adipose tissue is more metabolically active than other fat depots and is more closely associated with obesity-related diseases, such as cardiovascular disease and type 2 diabetes, than indicators of obesity, such as body mass index. Across various strategies to promote weight loss, including energy-reduced diet and exercise, variable effects on VAT compared to loss of total body fat have been reported. METHODS: To examine the effect of a behavioral weight loss intervention using portion-controlled prepackaged entrées on VAT, we examined data and measurements from overweight/obese men and women (N=183) who were assigned to a weight loss intervention and prescribed a reduced-energy diet with either portion-controlled prepackaged entrées or self-selected meals in a randomized clinical trial. VAT was estimated with dual-energy X-ray absorptiometry at baseline and study end (12 weeks). RESULTS: VAT loss was greater for the prepackaged entrees group (p=0.02), with an average loss of 29% compared to an average loss of 19% among participants consuming self-selected meals. VAT (mean [SEM]) was 1651 (71) g and 1546 (157) g at baseline and 1234 (59) g and 1278 (118) g at study end in the prepackaged entrees and self-selected meal groups, respectively. Greater VAT loss was associated with higher baseline weight and VAT, and greater weight loss, but not associated with age or physical activity. CONCLUSION: Prescribing portion-controlled prepackaged entrees in a behavioral weight loss intervention promotes a reduction in VAT, which should promote improved metabolic profile and reduced cardiovascular disease risk.

Correlations among four measures of thoracic kyphosis in older adults.

SUMMARY: There are many ways to measure thoracic kyphosis ranging from simple clinical to more complex assessments. We evaluated the correlation among four commonly used kyphosis measures: Cobb angle, Debrunner kyphometer, kyphotic index, and the blocks method. Each measure was correlated with the others, confirming high clinical and research applicability. INTRODUCTION: The purpose of this study was to assess the associations among four commonly used measures of thoracic kyphosis in older adults. METHODS: Seventy two men and women aged 65-96 were recruited from the San Diego community. Four kyphosis measures were assessed in the same person during a baseline clinic visit. Two measures were done in the lying (L) and two in the standing (ST) position: (1) Cobb angle calculated from dual X-Ray absorptiometry (DXA) images (L), (2) Debrunner kyphometer (DK) angle measured by a protractor (ST), (3) kyphotic index (KI) calculated using an architect's flexicurve ruler (ST), and (4) the blocks method involving counting the number of 1.7 cm-thick blocks required to achieve a neutral head position while lying flat on the DXA table (L). Spearman rank correlation coefficients were used to determine the strength of the association between each kyphosis measure. RESULTS: Using the Cobb angle as the gold standard, the blocks method demonstrated the lowest correlation (r(s) = 0.63, p < 0.0001), the Debrunner method had a moderate correlation (r(s) = 0.65, p < 0.0001), and the kyphotic index had the highest correlation (r(s) = 0.68, p < 0.0001). The correlation was strongest between the kyphotic index and the Debrunner kyphometer (r(s) = 0.76, p < 0.0001). CONCLUSION: In older men and women, all four measures of thoracic kyphosis were significantly correlated with each other, whether assessed in the lying or standing position. Thus, any of these measures demonstrate both potential clinical and research utility.

The risk of surgical site infection and re-admission in obese patients undergoing total joint replacement who lose weight before surgery and keep it off post-operatively.

This study evaluated whether obese patients who lost weight before their total joint replacement and kept it off post-operatively were at lower risk of surgical site infection (SSI) and re-admission compared with those who remained the same weight. We reviewed 444 patients who underwent a total hip replacement and 937 with a total knee replacement who lost weight pre-operatively and sustained their weight loss after surgery. After adjustments, patients who lost weight before a total hip replacement and kept it off post-operatively had a 3.77 (95% confidence interval (CI) 1.59 to 8.95) greater likelihood of deep SSIs and those who lost weight before a total knee replacement had a 1.63 (95% CI 1.16 to 2.28) greater likelihood of re-admission compared with the reference group. These findings raise questions about the safety of weight management before total replacement of the hip and knee joints.

Effect of training mode and calcium intake on bone mineral density in female master cyclist, runners, and non-athletes.

The focus of this prospective, observational study was to determine the effect of sport-specific training and calcium intake on bone mineral density (BMD) in female master cyclists, runners and non-athletes. Thirty women (12 cyclists, 9 runners, 9 controls), mean age of 49.6 +/- 7.9 years, were assessed at baseline and 18 months for calcium intake (4-day records), current exercise activity (recall questionnaire), and BMD of the lumbar spine and hip (DXA). A three (cyclists, runners, controls) by two (0 and 18 months) repeated measures ANOVA demonstrated a significant interaction effect of sport and time at the femoral neck (p <.04). Tukey post hoc analysis indicated that the BMD of the femur was maintained in cyclists and runners but declined in controls (p <.05). A significant time effect was noted in BMD at the lumbar spine (p <. 001) and the trochanter (p <.003). BMD of the lumbar spine was maintained in runners but declined in cyclists (p <.007) and in controls (p <.03), while trochanteric BMD declined in all groups (p <.01). No significant interaction effect of sport and dietary calcium intake was noted for BMD at any site.

Impact of a worksite behavioral skills intervention.

Sixty-four male and female sedentary employees were randomly assigned to an intervention group or control group to determine the effects of behavioral skill training on adoption and maintenance of exercise. Both received a 9-month membership at a local fitness facility. The control group received a 12-week semistructured course, which included a facility orientation and three meetings with a personal trainer. The intervention group received a 12-week behavioral skills course and were encouraged to participate in a 12-week semistructured exercise course followed by a 3-month problem-solving support intervention. Both groups improved their daily energy expenditure, the amount of moderate and vigorous activity they performed, and their strength and flexibility. The study sample was too small to show substantial differences between the intervention and control group. Changes in mediator variables were mixed.

Retraining of a competitive master athlete following traumatic injury: a case study.

PURPOSE: The purpose of this study was to examine the physiological effects of detraining and retraining in a female master cyclist (age, 49.5 yr; wt, 54 kg) following a surgically-treated clavicular fracture complicated by brachial plexus impingement. METHODS: Variables associated with cycling performance, including VO2max, lactate threshold (LT), power output at a blood lactate concentration of 4 mM (LT(4 mM)), peak power output (PPO), muscular resistance to fatigue measured by a timed ride to exhaustion at 110% of peak power output (PPO110), and body composition (hydrostatic weight) were assessed 2 d before the injury when the subject was at the peak of her competitive season, and at days 0, 14, 28, 42, and 77 of the retraining period. Retraining gradually increased from 3 h x wk(-1) to 9-10 h x wk(-1) with an increase in intensity from approximately 70 to 95+% of HRmax. RESULTS: Detraining resulted in a 25.7% decrease in VO2max and a 16.7% and 18.9% decrease in LT and LT(4 mM), respectively, while peak power output and PPO110 declined 18.2% and 16.6%, respectively. Body fat percent increased 2.1 percentage points, while fat-free mass decreased nearly 2 kg. After 2 wk of retraining, all variables except the LT and LT(4 mM) had improved considerably; however, VO2max was still 14.8% lower and PPO and PPO110 were 12.7% and 5.7% lower than preinjury values. By the 11th week of retraining, all variables had essentially returned to their preinjury values. CONCLUSION: These data demonstrate a pattern of retraining in which aerobic power steadily improved over 6 wk, while measures of lactate threshold did not change until the fourth week of retraining when the intensity of training was markedly increased. Additional data are needed to determine whether this pattern of retraining would be consistent in other master athletes.

Project GRAD: two-year outcomes of a randomized controlled physical activity intervention among young adults. Graduate Ready for Activity Daily.

INTRODUCTION: Project Graduate Ready for Activity Daily evaluated a program to promote physical activity through the transition of university graduation in a randomized controlled trial. METHODS: Three hundred thirty-eight university seniors participated in either a cognitive-behavioral intervention course or a knowledge-oriented general health course during the semester before graduation. Behaviorally oriented phone and mail follow-up was delivered to the intervention group for 18 months. Physical activity outcomes and mediating variables were assessed at baseline, 1 and 2 years (93% retention rate). RESULTS: There were no significant intervention effects on physical activity outcomes at 2 years for either men or women. Experiential and behavioral processes of change were significantly improved for intervention women over 2 years. CONCLUSIONS: Despite excellent participation in a theoretically based, well-attended intervention, few long-term effects on physical activity or its mediators were found. Additional research is needed to determine optimal interventions for physical activity and to validate or alter current behavior change theory.

Assessment of physical activity with the Computer Science and Applications, Inc., accelerometer: laboratory versus field validation.

Our purpose was to compare the validity of the Computer Science and Applications, (CSA) Inc., accelerometer in laboratory and field settings and establish CSA count ranges for light, moderate, and vigorous physical activity. Validity was determined in 60 adults during treadmill exercise, using oxygen consumption (VO2) as the criterion measure, while 30 adults walked and jogged outdoors on a 400-m track. The relationship between CSA counts and VO2 was linear (R2 = .89 SEE = 3.72 ml.kg-1.min-1), as was the relationship between velocity and counts in the field (R2 = .89, SEE = 0.89 mi.hr-1). However, significant differences were found (p < .05) between laboratory and field measures of CSA counts for light and vigorous intensity. We conclude that the CSA can be used to quantify walking and jogging outdoors on level ground; however, laboratory equations may not be appropriate for use in field settings, particularly for light and vigorous activity.

Self-report measures and scoring protocols affect prevalence estimates of meeting physical activity guidelines.

PURPOSE: Prevalence estimates of meeting the guidelines for physical activity based on various self-report measures were compared, and the effects of various scoring protocols on the estimates were evaluated. METHOD: A sample of 575 university students aged 24.5 +/- 1.9 yr (56% women, 54% Euro-American) completed the Seven-Day Physical Activity Recall interview (PAR), Youth Risk Behavior Survey (YRBS), and National Health Interview Survey 1991 (NHIS). To determine the prevalence of meeting the ACSM (1990) fitness and the CDC/ACSM (1995) health-related guidelines, various scoring protocols were employed that closely approximated the recommendations. Protocols varied by whether frequency and duration or duration only were considered. For the health-related guidelines, scoring protocols also varied depending on the intensity of activities considered. RESULTS: Depending on the scoring protocol and instrument used, the proportion meeting the fitness guidelines ranged from 32 to 59%. The NHIS, YRBS, and PAR resulted in significantly different proportions of those meeting the health-related guideline, ranging from 4 to 70%. CONCLUSION: The type of measure as well as the scoring protocol affected prevalence estimates of meeting the physical activity guidelines. This study indicates the difficulty of comparing prevalence rates across studies using different measures.

Validity, reliability, and calibration of the Tritrac accelerometer as a measure of physical activity.

PURPOSE: The purposes of this study were to assess the validity and reliability of the Tritrac R3D accelerometer during treadmill walking and running and then to calibrate the instrument. METHODS: The Tritrac was assessed on 60 young adults (23.4 +/- 2.9 yr) during treadmill walking and running at 3.2, 6.4, and 9.7 km x h(-1). The calibration was carried out by identifying ranges of Tritrac raw data (vector magnitude) values corresponding to light (2-3.9 MET), moderate (4-7 MET), and vigorous (>7 MET) physical activity. Energy expenditure (EE), measured by indirect calorimetry, served as the criterion measure. RESULTS: Interinstrument intraclass reliability coefficients for Tritracs worn on the right and left hip ranged from 0.73-0.87, while intersession coefficients demonstrated high reliability for all speeds (R = 0.87-0.92). Paired t-tests comparing mean accelerometer counts at 6.4 km x h(-1), 0% grade (2647 +/- 456), and 6.4 km x h(-1), 5% grade (2635 +/- 435) demonstrated no significant difference (P > 0.05). Mean differences between EE measured by indirect calorimetry and that estimated by the Tritrac ranged from 0.0082 kcal x kg(-1) x min(-1) at 3.2 km x h(-1) to 0.0320 kcal x kg(-1) x min(-1) at 9.7 km x h(-1), with the Tritrac consistently overestimating EE during horizontal treadmill walking. The relationship between vector magnitude and EE across all speeds was highly linear (R2 = 0.90, SEE = 0.014 kcal x kg(-1) x min(-1)), with little overlap between light, moderate, and vigorous categories. The mean vector magnitudes at 2, 4, and 7 MET were 650, 1772, and 3455, respectively. CONCLUSIONS: These data indicate that the Tritrac is highly reliable from day to day and is sensitive to changes in speed but not grade. Furthermore, the Tritrac accurately distinguishes various intensities of walking and jogging on level ground. With limitations, these cut-points can be used to categorize light, moderate, and vigorous physical activity and to estimate EE.

Evaluation of a university course to promote physical activity: project GRAD.

Project GRAD (Graduate Ready for Activity Daily) evaluates a university course to promote physical activity. In a randomized study, 338 university seniors participated in either an intervention or control course for academic credit, and posttest data were collected on 321. The control course was knowledge-oriented. The intervention course taught behavior change skills in weekly lectures and peer-led labs. Physical activity was assessed with 7-Day Physical Activity Recall interviews. The intervention had no significant effects on men. Among women, the intervention increased total physical activity during leisure, strengthening exercises, and flexibility exercise. This university course had the intended effects of promoting healthful patterns of physical activity among women, but no effects were observed on men, who were more active than women at baseline.

Interrelationships between physical activity and other health behaviors among university women and men.

BACKGROUND: The interrelationships among health behaviors are not well understood. The present study examines health behaviors and their relations to various types of physical activity among university seniors. METHODS: The study sample was an ethnically diverse group of 576 men and women (mean age 24.5 +/- 2 years) recruited from a large urban university. Physical activity was assessed with a modification of the Blair Seven-Day Recall by telephone interview, and health behaviors were assessed with the CDC's Youth Risk Behavior Survey, College Version. Hierarchical multiple regressions were conducted to determine whether health behaviors of men and women were associated with physical activity after adjusting for potential demographic confounders. RESULTS: Nineteen health behavior items were factor analyzed, yielding 5 factors: tobacco use, drinking and driving, unsafe sex, eating fatty foods, and eating healthy foods. Physical activity measures included leisure-time moderate and vigorous activities, flexibility, and strengthening activities. For men, a significant relation was found between three of four indices of physical activity and eating healthy foods (P < 0.05), but no association was noted with other health behaviors. For women, vigorous physical activity was related to eating healthy foods, and strengthening activities were related to eating fewer fatty foods (P < 0.05). CONCLUSIONS: Consistent with previous studies, physical activity was found to have modest associations with eating behaviors but not with other health-related behaviors.

Relationship between blood lactate response to exercise and endurance performance in competitive female master cyclists.

The blood lactate response to graded exercise and its relationship to performance in the field was examined in highly competitive female master cyclists. Thirteen women, age 47.5+/-2.2yr (mean+/-SE), all of whom were United States Cycling Federation (USCF) competitors, underwent laboratory testing for aerobic capacity (VO2max) and lactate threshold (LT), and field testing for performance in 13.5 km and 20 km time-trials. The mean VO2max of the subjects (50.6+/-2.7 ml x kg(-1) x min[-1]) was approximately 10% higher than that previously reported for other age-matched female athletes and correlated moderately (r=-0.67) with age. Maximal heart rate was unrelated to age (r=-0.25, p>0.05). Blood lactate concentration (BLC) while time-trialing was significantly higher than that at the LT (2.86+/-0.17 mmol x l[-1]) for both the 13.5 km (7.59 mmol x l(-1), p < 0.0001), and the 20 km trials (6.99 mmol x l(-1), p<0.002). The LT occurred at a mean power output of 168+/-11.3 W and 66% of VO2max. The VO2 corresponding to a BLC of 4.0 mmol x l(-1) (LT4) was 72% of VO2max. As expected, time-trial performance was highly correlated with VO2max (r=-0.85); however, regression analysis indicated that power output at the lactate threshold was the best laboratory predictor of performance (13.5 km: r2 = 0.83; 20 km: r2 = 0.78). Relative to maximal heart rate, heart rate at LT (88% HRmax) was significantly (p<0.05) lower than time-trial heart rate (92-94% HRmax). The cyclists in this study have higher aerobic capacities and maximal heart rates than those previously reported for other age-matched female athletes and are able to cycle for extended periods at blood lactate concentrations significantly higher than those at the lactate threshold. Traditional methods of exercise prescription, particularly when using age-estimates of maximal heart rate, underestimate training intensities required to be above the LT in female master cyclists.

Assessing perceived physical environmental variables that may influence physical activity.

The present study evaluated a measure of perceived physical environments that may influence physical activity. Forty-three self-report items were used to assess environmental variables at homes, in neighborhoods, or on frequently traveled routes. The presence of facilitators of (e.g., equipment, programs, attractive surroundings) and barriers to (e.g., high crime) physical activity was assessed. In 110 college students, test-retest reliabilities were .89 for the home equipment scale, .68 for the neighborhood scale, and .80 for the convenient facilities scale. Home equipment and convenient facilities scales were correlated with self-reported physical activity. In multiple regression analyses, the only significant association, after adjusting for neighborhood socioeconomic status, was home equipment with strength exercise. Further research is needed to identify other environmental characteristics that may influence physical activity.