Search Results

You are looking at 101 - 110 of 279 items for :

  • "treadmill" x
  • Psychology and Behavior in Sport/Exercise x
Clear All
Restricted access

Neha Singhal and Anupa Siddhu

Background:

The relationship between leisure-time physical activity (LTPA) and cardiorespiratory fitness (CRF) is not clearly understood in Indian men. It is important to elucidate whether the duration or intensity of LTPA is responsible for increasing CRF. This will help in designing better physical activity intervention strategies for improving CRF in Indian men.

Methods:

Healthy nondiabetic urban Indian men with no history of coronary heart disease (CHD) were selected (n = 603; aged 22–64 years) and their energy intake and physical activity was determined using a questionnaire. Body fat (percent) was determined by leg-to-leg bioelectrical impedance analysis while CRF was measured on multistage, continuous treadmill test using Bruce protocol.

Results:

Intensity of physical activity (METs) emerged as the best independent predictor of CRF (β = 0.217; P < .001). Using univariate General Linear Model, it was found that CRF is more a function of LTPA intensity than LTPA duration, since LTPA duration was not related to CRF when controlled for LTPA intensity. However, LTPA intensity remained significantly associated with CRF even after adjustment for LTPA duration.

Conclusion:

LTPA of preferably higher intensity should be incorporated in the lifestyle to improve CRF and prevent CHD in Indian men.

Restricted access

Larry Tucker and Travis Peterson

Background:

This study was conducted to determine if cardiorespiratory fitness at baseline, and changes in fitness, influence risk of weight gain (≥3 kg) over 20 months. Another aim was to ascertain if potential confounding factors, including age, education, strength training, energy intake, and weight, influence risk of weight gain.

Methods:

In a prospective study of 257 women, fitness (VO2max) was assessed using a graded, maximal treadmill test at baseline and follow-up. Energy intake was measured using 7-day, weighed food records. Subjects were divided into quartiles based on fitness. Risk ratios were used to show the risk of weight gain among those who were fit at baseline compared with their counterparts.

Results:

Most women gained weight and 23% gained ≥3 kg. Mean VO2max was 35.7 ± 7.2 mL·kg−1·min−1. Women with low-fitness at baseline had 3.18 times (95% CI: 1.46 to 6.93) greater risk, and moderately fit women had 2.24 times (95% CI: 1.04 to 4.82) greater risk of weight gain than women in the high-fitness quartile. Adjusting for potential confounders had little effect on results.

Conclusions:

High levels of fitness seem to help protect middle-aged women against weight gain, whereas low and moderate fitness increase risk of weight gain over time.

Restricted access

Soyang Kwon, Trudy L. Burns and Kathleen Janz

Background:

This study aimed to examine combined and independent effects of cardiorespiratory fitness and fatness on cardiovascular risk factors among U.S. adolescents.

Methods:

Data from adolescents age 12 to 19 years participating in the NHANES 1999 to 2002 were used. Fitness level was determined by submaximal treadmill test and was dichotomized as ‘not fit’ or ‘fit’ according to the FITNESSGRAM. Fatness level was categorized as ‘not fat’ or ‘fat’ based on the CDC BMI growth charts. Gender-specific multivariable linear regression analyses were conducted to compare age-, race/ethnicity-, fatness-, and waist circumference-adjusted means of blood pressure, lipids, lipoproteins, C-peptide, insulin, and C-reactive protein (CRP) levels.

Results:

A total of 3202 adolescents (1629 boys) were included for data analysis. Among boys, total cholesterol, tri-glycerides, insulin, and CRP mean levels were significantly higher (P < .05) in the ‘not fit’ group than in the ‘fit’ group, after adjustment for fatness level and waist circumference. Among girls, the fatness level- and waist circumference-adjusted means of total cholesterol (P < .01) and LDL-C (P < .09) were higher in the ‘not fit’ than ‘fit’ groups.

Conclusion:

Cardiorespiratory fitness, independent of fatness, may have beneficial effects on lipid profiles among girls, and on lipid profiles, insulin metabolism, and inflammation levels among boys.

Restricted access

Lynnette M. Jones, Debra L. Waters and Michael Legge

Background:

Walking is usually undertaken at a speed that coincides with the lowest metabolic cost. Aging however, alters the speed–cost relationship, as preferred walking speeds decrease and energy costs increase. It is unclear to what extent this relationship is affected when older women undertake walking as an exercise modality. The aim of this study was to compare the energetic cost of walking at a self-selected exercise pace for 30 min in older and younger women.

Methods:

The energetic cost of walking was assessed using the energy equivalent of oxygen consumption measured in 18 young (25 to 49 y) and 20 older (50 to 79 y) women who were asked to walk at their “normal” exercise pace on a motorized treadmill for 30 min.

Results:

The mass-specific net cost of walking (Cw) was 15% higher and self-selected walking speed was 23% lower in the older women than in the younger group. When speed was held constant, the Cw was 0.30 (J · .kg−1 · m−1) higher in the older women.

Conclusions:

Preferred exercise pace incurs a higher metabolic cost in older women and needs be taken into consideration when recommending walking as an exercise modality.

Restricted access

Jessica L. Unick, Kelley Strohacker, George D. Papandonatos, David Williams, Kevin C. O’Leary, Leah Dorfman, Katie Becofsky and Rena R. Wing

This study examined whether inactive, overweight/obese women experience consistent affective responses to moderate-intensity exercise. Twenty-eight women participated in 3 identical (same treadmill grade and speed within a subject) 30-min exercise sessions. The Feeling Scale (FS), Positive and Negative Affect Schedule and Subjective Exercise Experience Scale were administered pre- and postexercise and FS was also administered every 5 min during exercise. All measures exhibited less than optimal agreement in pre-to-postexercise change within an individual across the 3 sessions (ICCs = 0.02–0.60), even after controlling for within-subject variations in heart rate. Only FS exhibited “good” consistency when controlling for preexercise values (ICC = 0.72). However, the mean FS score during exercise was highly consistent within an individual (ICC = 0.83). Thus, an individual’s affective response to an exercise session does not provide reliable information about how they will respond to subsequent exercise sessions. Taking the average of FS measurements during exercise may yield more consistent findings.

Restricted access

Stephen R. Bird, Simon C. Theakston, Andrew Owen and Alan M. Nevill

This study assessed physiological and cardiac factors associated with 10-km running performance in a group of highly trained endurance runners age 21–63 years. Participants (N = 37) underwent a resting echocardiograph and incremental treadmill running test. They also provided information on their recent 10-km races. Data were analyzed using “best subsets” multiple regression. Declines with age were found for 10-km running speed (0.26 m · s−1 · decade−1), maximum heart rate (4 beats/decade), VO2peak (6 ml · kg−1 · min−1 · decade−1), velocity at lactate threshold (1 m · s−1 · decade−1), and VO2 at lactate threshold (4 ml · kg−1 · min−1 · decade−1). The percentage of VO2peak at which lactate threshold occurred increased with age by 1.5% per decade. The rate of change of displacement of the atrioventricular plane at the left free wall and septum both declined by 1 cm · s−1 · decade−1. The best single predictor of 10-km running speed was velocity at lactate threshold.

Restricted access

Susan Vincent Graser, Alan Groves, Keven A. Prusak and Todd R. Pennington

Background:

Researchers have noted both the utility and limitations of using pedometers to measure physical activity (PA). While these unobtrusive devices are widely accepted for their ability to measure accumulated PA, they have been criticized for their inability to measure exercise intensity. However, recent steps-per-minute (SPM) research provides reasonably accurate measures of intensity allowing users to assess time spent at recommended PA levels. Therefore, the purpose of this study was to determine the SPM taken that are associated with moderate physical activity in 12- to 14-year-old youth.

Methods:

Ninety-three participants (49 boys and 44 girls; ages 12 to 14) walked on a treadmill for 3 minutes at each of 4 different speeds while wearing a pedometer and a heart rate monitor.

Results:

On average boys and girls reached their moderate activity intensity threshold at 122 SPM and 102 SPM, respectively. However, individual differences must be taken into account when determining appropriate SPM intensities for youth.

Conclusions:

The impact of individual differences underscores the need to address SPM for moderate intensity individually rather than with a single guideline for everyone at this age.

Restricted access

Michael J. Davies, Gail P. Dalsky and Paul M. Vanderburgh

This study employed allometry to scale maximal oxygen uptake (V̇O2 max) by body mass (BM) and lean body mass (LBM) in healthy older men. Ratio standards (ml · kg−1 · min−1) derived by dividing absolute V̇O2 max (L · min−1) by BM or LBM often fail to control for the body size variable. The subjects were 73 older men (mean ± SD: age = 69.7 ± 4.3 yrs, BM = 80.2 ± 9.6 kg, height = 174.1 ± 6.9 cm). V̇O2 max was assessed on a treadmill with the modified Balke protocol (V̇O2 max = 2.2 ± 0.4 L · min−1). Body fat (27.7 ± 6.4%) was assessed with dual energy x-ray absorptiometry. Allometry applied to BM and V̇O2 max determined the BM exponent to be 0.43, suggesting that heavier older men are being penalized when ratio standards are used. Allometric scaling applied to LBM revealed the LBM exponent to be 1.05 (not different from the ratio standard exponent of 1.0). These data suggest that the use of ratio standards to evaluate aerobic fitness in older men penalized fatter older men but not those with higher LBM.

Restricted access

Sae Young Jae, Kevin Heffernan, Bo Fernhall and Yoon-Ho Choi

Background:

We tested the hypothesis that higher levels of cardiorespiratory fitness are inversely associated with carotid artery intima media thickness in 746 (age 53 ± 7 yrs) men with type 2 diabetes.

Methods:

We measured common carotid intima media thickness and defined carotid atherosclerosis as a carotid intima media thickness > 1.0 mm. Cardiorespiratory fitness was directly measured by peak oxygen uptake using expired gases analysis during a standard treadmill test.

Results:

Cardiorespiratory fitness was independently associated with common carotid intima media thickness in multivariable regression (β = –0.15, P < .05). After adjusting for established risk factors, high and moderate cardiorespiratory fitness were associated with lower odds ratios for having carotid atherosclerosis—0.49 (95% CI, 0.30–0.81), and 0.59 (95% CI, 0.38–0.92), respectively—as compared with low cardiorespiratory fitness. Each 1 metabolic equivalent increment higher cardiorespiratory fitness was associated with 27% (OR = 0.73; 95% CI, 0.61–0.87) lower prevalence of carotid atherosclerosis.

Conclusions:

These results suggest that high cardiorespiratory fitness is inversely associated with common carotid intima media thickness in men with type 2 diabetes.

Restricted access

Patrick B. Wilson

Background:

Psoriasis confers risk for cardiometabolic disorders. Cardiorespiratory fitness is inversely associated with risk of cardiometabolic disorders in other populations, but limited data have been published assessing cardiorespiratory fitness among individuals with psoriasis. This investigation aimed to: 1) assess cardiorespiratory fitness among individuals with psoriasis in the general population; and 2) compare levels to individuals without psoriasis.

Methods:

A secondary data analysis from the 2003–2004 National Health and Nutritional Examination Survey was performed. Cardiorespiratory fitness was assessed with a treadmill test, while measures of psoriasis severity included rating of psoriasis as a life problem and body surface area involvement.

Results:

Twenty-six of 1093 participants reported a psoriasis diagnosis (population weighted prevalence 2.9%). Individuals with psoriasis had lower cardiorespiratory fitness compared with individuals without psoriasis (36.2 vs. 39.1 mL∙kg-1∙min-1, P = .009). No differences in self-reported or accelerometer physical activity were found by psoriasis diagnosis. Cardiorespiratory fitness was not significantly lower in those reporting high life impairment or body surface area involvement.

Conclusions:

Cardiorespiratory fitness may be lower in individuals with psoriasis and these differences may not be explained by self-reported disease severity measures or physical activity. Future studies should examine whether validated measures of psoriasis severity predict lower cardiorespiratory fitness.