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W. Jack Rejeski, Charles J. Hardy and Janet Shaw

This investigation examined the possible psychometric confounds of interpreting exercise-induced symptom reporting as changes in stete anxiety. Thirty male subjects exercised on a motor-driven treadmill for 15 min at 75% of maximum heart rate reserve. Prior to» during, and following the exercise, subjects responded to short forms of Spielberger's State Anxiety Inventory (SAI), Thayer's Aetivation-Deactivation Adjective Check List (AD-ACL), Borg's Rating of Perceived Exertion (RPE) scale» and a measure of affect. Preliminary results indicated that following 10 min of recovery from exercise» SAI scores were lower than baseline responses. Upon former analysis of individual SAI items, however, it was evident mat changes occurring in total SAI scores as a result of exercise were strongly influenced by changes in energetic arousal and general deactivation. This conclusion was supported by data from the AD-ACL as well as responses to postexperimental interviews. These findings cal into question the construct validity of the SAI and related state measures (e.g., the Profile of Mood States» or POMS) when used in conjunction with acute bouts of vigorous physical activity.

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Carmelo Bazzano, Lee N. Cunningham, Giovanni Cama and Tony Falconio

This study examined the physiology of the 1-mile walk test as administered in the field with 16 (7 M, 9 F) older adults (mean age 66.1 ± 5.9 yrs). Physiologic data were obtained via a Cosmed K2 miniaturized O2 analyzer with telemetric capabilities during a maximal treadmill (TM) test and a 1-mile walk test (MWT). Oxygen consumption (ml · kg−1 · min−1), minute ventilation (L · min−1), and heart rate (b · min−1) values obtained at maximal levels on the TM were 25.6 ± 7.6, 57 ± 17, and 155 ± 16, respectively. The measured V̇O2 submax during the MWT was 18.5 + 5, V̇E submax was 44 ± 10, and HR submax was 140 ± 19. The subjects were able to hold 74% of the V̇O2max, 81% of V̇Emax, and 91% of HR max. An upward drift for HR and V̇E was noted while V̇O2 remained constant throughout the MWT. The MWT with older subjects requires a vigorous level of metabolic and cardiorespiratory intensity. For healthy older adults who have been properly screened for hidden metabolic and cardiovascular diseases, participation in the MWT appears feasible.

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Kate Lyden, Sarah Kozey Keadle, John Staudenmayer, Patty Freedson and Sofiya Alhassan

Background:

The Compendium of Energy Expenditures for Youth assigns MET values to a wide range of activities. However, only 35% of activity MET values were derived from energy cost data measured in youth; the remaining activities were estimated from adult values.

Purpose:

To determine the energy cost of common activities performed by children and adolescents and compare these data to similar activities reported in the compendium.

Methods:

Thirty-two children (8−11 years old) and 28 adolescents (12−16 years) completed 4 locomotion activities on a treadmill (TRD) and 5 age-specific activities of daily living (ADL). Oxygen consumption was measured using a portable metabolic analyzer.

Results:

In children, measured METs were significantly lower than compendium METs for 3 activities [basketball, bike riding, and Wii tennis (1.1−3.5 METs lower)]. In adolescents, measured METs were significantly lower than compendium METs for 4 ADLs [basketball, bike riding, board games, and Wii tennis (0.3−2.5 METs lower)] and 3 TRDs [2.24 m·s-1, 1.56 m·s-1, and 1.34 m·s-1 (0.4−0.8 METs lower)].

Conclusion:

The Compendium of Energy Expenditures for Youth is an invaluable resource to applied researchers. Inclusion of empirically derived data would improve the validity of the Compendium of Energy Expenditures for Youth.

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Amy L. Nikolai, Brittany A. Novotny, Cortney L. Bohnen, Kathryn M. Schleis and Lance C. Dalleck

Background:

The purposes of this study were (1) to assess the cardiovascular and metabolic responses to water aerobic exercise and (2) to determine if water aerobics exercise meets the American College of Sports Medicine (ACSM) guidelines for improving and maintaining car-diorespiratory fitness.

Methods:

Fourteen men and women—mean ± SD age 57.4 ± 7.6 y, height 171.3 ± 7.8 cm, weight 89.9 ± 13.9 kg, body-fat percentage 32.5% ± 5.8%, and maximal oxygen uptake (VO2max) 31.0 ± 8.3 mL · kg−1 · min−1—completed a maximal treadmill exercise test and a 50-min water aerobics session. Cardiovascular and metabolic data were collected via a portable calorimetric measurement system.

Results:

Mean exercise intensity was 43.4% of heart-rate reserve and 42.2% of maximal oxygen uptake reserve. Training intensity in metabolic equivalents was 4.26 ± 0.96. Total net energy expenditure for the exercise session was 249.1 ± 94.5 kcal/session.

Conclusions:

Results indicate that water aerobics is a feasible alternative to land-based exercise for middle-aged and older adults that fulfills the ACSM guidelines for improving and maintaining cardiorespiratory fitness.

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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.

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Gina Bravo, Pierre Gauthier, Pierre-Michel Roy, Daniel Tessier, Philippe Gaulin, Marie-France Dubois and Lucie Péloquin

A battery of field tests was recently developed to assess five fitness parameters in elderly persons. The present study examined the test-retest reliability of each item in the battery and tested the validity of the cardiorespiratory endurance item. Reliability and validity data were obtained from two convenience samples. The 29 subjects in the reliability study were community-living women enrolled in seniors’ exercise classes. The validity of the cardiorespiratory endurance item was tested by comparing it with maximal work capacity on a treadmill test. The 52 women in that part of the study were all participants in a study to assess the effect of weight-bearing exercises on women with low bone mass. Both samples were combined for a principal component analysis. Low reproducibility was observed for coordination (0.54) and strength/endurance (0.56). After slightly modifying the test protocol for these two items, reproducibility reached 84 and 94%, respectively. The correlation between the cardiorespiratory endurance score and maximal work capacity was −0.65, while that between the composite score and maximal work capacity was −0.64. Given these minor modifications, then, the Functional Fitness Assessment battery is a reliable and valid tool for assessing functional fitness in elderly women.

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Charles F. Morgan, Allison R. Tsuchida, Michael William Beets, Ronald K. Hetzler and Christopher D. Stickley

Background:

Physical activity guidelines for youth and adults include recommendations for moderate intensity activity to attain health benefits. Indirect calorimetry studies have consistently reported a 100 ste·min−1 threshold for moderate intensity walking in adults. No indirect calorimetry studies have investigated step-rate thresholds in children and therefore the primary purpose of the study was to determine preliminary step-rate thresholds for moderate physical activity walking in children.

Methods:

Oxygen consumption was measured at rest and used to determine 3 and 4 age-adjusted metabolic equivalents (A-AMETs) for 4 treadmill trials (self-selected, 2.5, 3.0, and 3.5 MPH). Two trained observers simultaneously counted children’s steps during each walking trial. Step-rate thresholds associated with moderate-intensity activity, defined as 3 and 4 A-AMETs, were determined using hierarchical linear modeling.

Results:

Regression analysis determined an overall step rate of 112 and 134 step·min-1 for 3 and 4 A-AMETs respectively. Body mass index (BMI) weight status and age were positively related to A-AMETs.

Conclusions:

We suggest age and BMI weight status specific recommendations that range from a low of 100 step·min-1 threshold (3 A-AMETs) for overweight/obese 11- to 12-year-olds to a high of 140 step·min-1 threshold (4 A-AMETs) for healthy weight 9- to 10-year-old children.

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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.

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James J. McClain, Teresa L. Hart, Renee S. Getz and Catrine Tudor-Locke

Background:

This study evaluated the utility of several lower cost physical activity (PA) assessment instruments for detecting PA volume (steps) and intensity (time in MVPA or activity time) using convergent methods of assessment.

Methods:

Participants included 26 adults (9 male) age 27.3 ± 7.1 years with a BMI of 23.8 ± 2.8 kg/m2. Instruments evaluated included the Omron HJ-151 (OM), New Lifestyles NL-1000 (NL), Walk4Life W4L Pro (W4L), and ActiGraph GT1M (AG). Participants wore all instruments during a laboratory phase, consisting of 10 single minute treadmill walking bouts ranging in speed from 40 to 112 m/min, and immediate following the laboratory phase and during the remainder of their free-living day (11.3 ± 1.5 hours). Previously validated AG MVPA cutpoints were used for comparison with OM, NL, and W4L MVPA or activity time outputs during the laboratory and free-living phase.

Results:

OM and NL produced similar MVPA estimates during free-living to commonly used AG walking cutpoints, and W4L activity time estimates were similar to one AG lifestyle cutpoint evaluated.

Conclusion:

Current findings indicate that the OM, NL, and W4L, ranging in price from $15 to $49, can provide reasonable estimates of free-living MVPA or activity time in comparison with a range of AG walking and lifestyle cutpoints.

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Candace D. Perkins, James M. Pivarnik and Matthew R. Green

Background:

The reliability and validity of the SensorMedics VmaxST was tested.

Methods:

Thirty subjects (age = 24.5 ± 4.0 years, height = 174.8 ± 9.8 cm, weight = 70.3 ± 12.6 kg) performed treadmill exercise on three occasions, twice using the VmaxST and once using the SensorMedics 2900 system. Oxygen consumption (VO2; L/min) and heart rate (HR; beats/min) were measured continuously during three, 6- minute stages: 80 m/min, 0% grade; 94 m/min, 5% grade; and 160 m/min, 0% grade, and VO2max.

Results:

Reliability was high, and measurement error was low for VO2 (Rxx range = 0.97 - 0.99, CI = 0.94 - 1.00, SEM = 0.03 - 0.08 L/min) and HR (Rxx = 0.94 - 0.99, CI = 0.88 - 1.00, SEM = 1.8 - 3.2 beats/min). Validity was high for VO2 (Rxy range = 0.92 - 0.98, CI = 0.84 - 0.99, SEE = 0.08 - 0.21 L/min) and HR (Rxy = 0.97 - 0.99, CI = 0.94 - 1.00, SEE = 0.9 - 1.8 beats/min). Mean differences in VO2 between VmaxST and 2900 were small yet significant (P < 0.001).

Conclusions:

The VmaxST demonstrated excellent reliability and validity for measuring VO2 and HR over several exercise intensities. Small overestimates in VO2 by the VmaxST are countered by low measurement error.