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Julian David Pillay, Tracy Lynn Kolbe-Alexander, Willem van Mechelen and Estelle Victoria Lambert

Background:

Pedometer-based recommendations for accumulating steps/d largely focus on volume, with less emphasis on intensity and fitness/health outcomes. We aim to examine this relationship.

Methods:

A convenience sample (N = 70, 35 men, 32 ± 8yrs) wore a pedometer (4 days). The pedometer classified steps as “aerobic” (≥ 60 steps/minute, minimum duration of 1 minute) or “non-aerobic” (< 60 steps/minute and/or < 1 minute). Estimated maximal oxygen uptake (VO2max), derived from a 12-minute submaximal step-test, and health outcomes: blood pressure (BP), body mass index (BMI), percentage body fat (%BF), and waist circumference (WC) were correlated with pedometer data. Participants were grouped according to number and intensity of steps: LOW (< 5000 steps/d), HIGH-LOW (≥ 5000 steps/d, no aerobic steps), HIGH-HIGH (≥ 5000 steps/d, including some aerobic steps). Analyses of covariance, adjusting for age, gender, and total steps/d were used to compare groups.

Results:

Average steps/d was 6520 ± 2306. Total steps/d and total time spent accumulating “aerobic” steps (minutes/day) were inversely associated with %BF, BMI, WC, and systolic BP (P < .05). After adjusting for gender and total steps/d, %BF was different between all 3 groups, VO2max was different between the LOW and HIGH-HIGH groups, WC was lower in the HIGH-HIGH versus the other 2 groups (P < .03, respectively).

Conclusion:

Intensity seems an important factor to consider in steps/d cut-points.

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Esther Morencos, Blanca Romero-Moraleda, Carlo Castagna and David Casamichana

In recent years, global positioning system (GPS) analysis has become a widely used tool for quantifying competition demands, informing training prescription, and monitoring the training stimulus. 1 In team sports such as hockey, considered as intermittent, high-intensity activity, 2 reductions in

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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.

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Shawn M. Arent, Daniel M. Landers, Kathleen S. Matt and Jennifer L. Etnier

The purpose of this study was to examine the dose-response gradient of exercise-induced affective change and the role of the stress response as a contributing mechanism. Male and female participants (N = 31) completed three different resistance training protocols (40%, 70%, and 100% of 10-repetition maximum [RM]) and a no-treatment control condition. Affective responses were assessed immediately before and at 0–5, 15, 30, 45, and 60 minutes postexercise. Salivary cortisol and heart rate (HR) responses were also assessed during each condition. As predicted, moderate intensity resistance training generally produced the greatest improvements in affect (p < .05). HR and cortisol accounted for as much as 27.3% and 5.4% of the affective variance, respectively. Findings support a curvilinear dose-response relationship between intensity and affective responses, with moderate intensity training resulting in immediate, large, and enduring affective benefits. Results also suggest that moderate activation of the stress response positively influences exercise-induced affective change.

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Renato Barroso, Ronaldo K. Cardoso, Everton Crivoi Carmo and Valmor Tricoli

Session rating of perceived exertion (SRPE) is a practical method to assess internal training load to provide appropriate stimuli. However, coaches and athletes might rate training sessions differently, which can impair performance development. In addition, SRPE might be influenced by athletes’ training experience. The authors studied 160 swimmers of different age groups and different competitive swimming experience and 9 coaches. SRPE was indicated by the swimmers 30 min after the end of a training session and before the training session by the coaches. Training-session intensities were classified into easy (SRPE <3), moderate (SRPE 3–5), and difficult (SRPE >5), based on coaches’ perception. We observed that the correlation between coaches’ and athletes’ SRPE increased with increased age and competitive swimming experience, r = .31 for the 11- to 12-y-old group (P < .001), r = .51 for the 13- to 14-y-old group (P < .001), and r = .74 for the 15- to 16-y-old group (P < .001). In addition, younger swimmers (11–12 y, P < .01; 13–14 y, P < .01) rated training intensity differently from coaches in all 3 categories (easy, moderate, and difficult), while the older group rated differently in only 1 category (difficult, P < .01). These findings suggest that the more experienced swimmers are, the more accurate their SRPE is.

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Vasilios I. Kalapotharakos, Maria Michalopoulou, George Godolias, Savvas P. Tokmakidis, Paraskevi V. Malliou and Vasilios Gourgoulis

The purpose of this study was to investigate the effects of a 12-week resistance-training program on muscle strength and mass in older adults. Thirty-three inactive participants (60–74 years old) were assigned to 1 of 3 groups: high-resistance training (HT), moderate-resistance training (MT), and control. After the training period, both HT and MT significantly increased 1-RM body strength, the peak torque of knee extensors and flexors, and the midthigh cross-sectional area of the total muscle. In addition, both HT and MT significantly decreased the abdominal circumference. HT was more effective in increasing 1-RM strength, muscle mass, and peak knee-flexor torque than was MT. These data suggest that muscle strength and mass can be improved in the elderly with both high- and moderate-intensity resistance training, but high-resistance training can lead to greater strength gains and hypertrophy than can moderate-resistance training.

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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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Saud F. Alsubaie, Susan L. Whitney, Joseph M. Furman, Gregory F. Marchetti, Kathleen H. Sienko and Patrick J. Sparto

The reliability of balance exercises performance in experimental and clinical studies has typically been confined to a small set of exercises. To advance the field of assessing balance exercise intensity, establishing the reliability of performance during a more diverse array of exercises should be undertaken. The purpose of this study was to investigate the test–retest reliability of postural sway produced during performance of 24 different balance tasks and to evaluate the reliability of different measures of postural sway. Sixty-two healthy subjects between the ages of 18 and 85 years (50% female and mean age = 55 [20] y) participated. Subjects were tested during 2 visits 1 week apart and performed 2 sets of the 24 randomized standing tasks per visit. The tasks consisted of combinations of the following factors: surface (firm and foam); vision (eyes open and eyes closed); stance (feet apart and semitandem); and head movement (no movement, yaw, and pitch). Angular position displacement, angular velocity, and linear acceleration postural sway in the pitch and roll planes were recorded by an inertial measurement unit. The postural sway measures demonstrated at fair to good test–retest reliability with few exceptions, and angular velocity measures demonstrated the greatest reliability. The between-visit reliability of 2 averaged trials was excellent for most tasks. The study indicates that the performance of most balance tasks used as part of balance rehabilitation is reliable and that quantitative assessment could be used to document change.

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Erik A. Willis, Amanda N. Szabo-Reed, Lauren T. Ptomey, Jeffery J. Honas, Felicia L. Steger, Richard A. Washburn and Joseph E. Donnelly

The American College of Sports Medicine recommends at least 150 minutes per week of moderate-intensity or 75 minutes per week of vigorous-intensity aerobic activity (minimum of 1000 kcal/wk of energy expenditure), in order to improve health outcomes 3 , 6 and 225 minutes per week (2000 kcal/wk of

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Ralph Beneke, Renate M. Leithäuser and Oliver Ochentel

A link between lactate and muscular exercise was seen already more than 200 years ago. The blood lactate concentration (BLC) is sensitive to changes in exercise intensity and duration. Multiple BLC threshold concepts define different points on the BLC power curve during various tests with increasing power (INCP). The INCP test results are affected by the increase in power over time. The maximal lactate steady state (MLSS) is measured during a series of prolonged constant power (CP) tests. It detects the highest aerobic power without metabolic energy from continuing net lactate production, which is usually sustainable for 30 to 60 min. BLC threshold and MLSS power are highly correlated with the maximum aerobic power and athletic endurance performance. The idea that training at threshold intensity is particularly effective has no evidence. Three BLC-orientated intensity domains have been established: (1) training up to an intensity at which the BLC clearly exceeds resting BLC, light- and moderate-intensity training focusing on active regeneration or high-volume endurance training (Intensity < Threshold); (2) heavy endurance training at work rates up to MLSS intensity (Threshold ≤ Intensity ≤ MLSS); and (3) severe exercise intensity training between MLSS and maximum oxygen uptake intensity mostly organized as interval and tempo work (Intensity > MLSS). High-performance endurance athletes combining very high training volume with high aerobic power dedicate 70 to 90% of their training to intensity domain 1 (Intensity < Threshold) in order to keep glycogen homeostasis within sustainable limits.