The purpose of this study was to determine the relationship between VO2max and the 1/2-mile run-walk and the reliability of each in children with mental retardation (MR). Twenty-three children (13 boys, 10 girls) with mild or moderate MR participated in the study. Two maximal treadmill protocols with metabolic measurements and two 1/2-mile run-walk trials were randomly conducted on separate days. There was no difference between Trial 1 and Trial 2 for VO2max (28.2 vs. 29.6 ml · kg−1 · min−1), maximal heart rate (175 vs. 177 bpm), or run-walk time (7.2 vs. 7.1 min). The test-retest correlations were r = .90 for VO2max, r = .81 for maximal heart rate, and r = .96 for the 1/2-mile run-walk (p < .05). The correlation between VO2max and the 1/2-mile run-walk was r = −.60 (p < .05). Adding body mass index to the model improved R to .67 (SEE = 7.3). The 1/2-mile run-walk was a reliable test, but had questionable validity as an indicator of aerobic capacity in children with mild and moderate MR.
Bo Fernhall, Ken Pitetti, Nancy Stubbs and Louis Stadler Jr.
Hans Luttikholt, Lars R. McNaughton, Adrian W. Midgley and David J. Bentley
There is currently no model that predicts peak power output (PPO) thereby allowing comparison between different incremental exercise test (EXT) protocols. In this study we have used the critical power profile to develop a mathematical model for predicting PPO from the results of different EXTs.
The purpose of this study was to examine the level of agreement between actual PPO values and those predicted from the new model.
Eleven male athletes (age 25 ± 5 years, VO2max 62 ± 8 mL · kg–1 · min–1) completed 3 laboratory tests on a cycle ergometer. Each test comprised an EXT consisting of 1-minute workload increments of 30 W (EXT30/1) and 3-minute (EXT25/3) and 5-minute workload increments (EXT25/5) of 25 W. The PPO determined from each test was used to predict the PPO from the remaining 2 EXTs.
The differences between actual and predicted PPO values were statistically insignificant (P > .05). The random error components of the limits of agreement of ≤30 W also indicated acceptable levels of agreement between actual and predicted PPO values.
Further data collection is necessary to confirm whether the model is able to predict PPO over a wide range of EXT protocols in athletes of different aerobic and anaerobic capacities.
David B. Pyne, Matt Spencer and Iñigo Mujika
One of the challenges for sports scientists working in football is to balance the needs for routine fitness testing with daily fatigue and well-being monitoring to best manage the physical preparation of players. In this commentary, the authors examine contemporary issues of fitness testing in football to identify ways of improving the value of routine testing and monitoring. A testing program must be well planned and organized to ensure that the results are useful. Different tests can be employed for younger and older players. A rigorous approach to analysis and interpretation of results is desirable, and database management must address both short- and long-term requirements of players, staff, and programs.
Jim Dollman and Kate Ridley
Evidence suggests that a substantial proportion of children meet guidelines for sufficient physical activity, but also exceed TV guidelines. Health-related consequences of this combination are unknown.
843 children, (age 10-11 y), were surveyed for health-related fitness [endurance performance (20 m MST), skinfolds, waist girth], daily TV and moderate-to-vigorous physical activity (MVPA). Children were grouped using daily TV (≤ 120 min) and MVPA (≥ 60 min) guidelines: hiTV-hiMVPA/“technoactives”’; hiTV-loMVPA/“screenies”; and loTV-hiMVPA/“sporties.” Groups were compared on health-related fitness measures.
There was a trend (P = 0.07) towards higher girls’ skinfolds among “screenies” than “sporties.” Boys’ waist girths were higher among “technoactives” than “sporties” (P = 0.008). Male “technoactives” outperformed “screenies” on the 20 m MST (P = 0.03). Female “sporties” (P = 0.004) and “technoactives” (P = 0.0002) outperformed “screenies” on the 20 m MST.
“Technoactives” were no different than “sporties” on endurance fitness but exhibited less favorable fat distribution among boys. Overall, “screenies” exhibited the least favorable health profiles.
Silvia Pogliaghi, Cecilia Bellotti and Donald H. Paterson
The authors developed and validated a “tailored” version of the Åstrand-Rhyming step test (tA-R) and a new equation for VO2max prediction in older adults (OA). Sixty subjects (age 68 ± 4 yr, 30 male, 30 female) performed their tA-R step test (5-min, 30-cm step, tailored stepping rate) and an incremental cycling test to exhaustion. VO2max was (a) predicted using the standard A-R equation (predictedVO2max), (b) predicted based on the authors’ new multiple linear equation (equationVO2max), and (c) directly measured by incremental cycling test (directVO2max). Agreement among values of VO2max was evaluated by Bland-Altman analysis. The predictedVO2max was not significantly different from the directVO2max, yet with relatively large imprecision. The equationVO2max allowed more precise as well as accurate predictions of VO2max compared with standard A-R prediction. The “tailored” version of the Åstrand-Rhyming step test and the new prediction equation appear suitable for a rapid (5-min), safe (submaximal), accurate, and precise VO2max prediction in healthy OA.
Stephen H. Boutcher, Barbara J. Meyer, Gemma A. Craig and Lee Astheimer
The relationship between aging, physical activity, and vagal influence on the heart was assessed by measuring resting heart period variability in postmenopausal women. Participants were 14 aerobically trained women (mean age 55 ± 1.0 years) and 20 untrained women (mean age 59 ± 1.1 years). Participants lay for 25 min while heart period variability was assessed during spontaneous and paced breathing (7.5 breaths · min-1). Heart period variability was assessed through time series analysis (HPVts) of the interbeat interval. Results indicated I that the trained women had significantly (p < .05) lower supine resting heart rate than the untrained group. HPVts at high frequencies during spontaneous and paced breathing was greater for trained compared to untrained participants. Similarly, HPVts at medium frequencies during spontaneous and paced breathing was greater for trained compared to untrained participants. Also, rate pressure product of the trained group was significantly lower than for the untrained. These results extend prior research by showing that aerobically trained postmenopausal women possessed significantly elevated resting vagal influence on the heart compared to their untrained counterparts.
Niina Lintu, Kai Savonen, Anna Viitasalo, Tuomo Tompuri, Jussi Paananen, Mika P. Tarvainen and Timo Lakka
There are few studies on determinants of cardiorespiratory fitness (CRF) among girls and boys separately in population samples of children.
We therefore investigated the determinants of CRF, assessed by maximal workload per height using allometric scaling, in a population sample of 162 girls and 177 boys aged 6 to 8 years. We used automated bootstrap feature selection and linear regression models.
The strongest determinants of CRF among girls were maximal heart rate (HR; standardized regression coefficient [β] = 0.31, P < .001), unsupervised physical activity (β = 0.29, P < .001), lean body mass (β = 0.23, P = .001), and errors in static balance test (β = –0.16, P = .02), accounting altogether for 25.7% of variation in CRF. In boys, unsupervised physical activity (β = 0.24, P < .001), resting HR (β = –0.25, P < .001), hand grip strength (β = 0.21, P = .001), errors in static balance test (β = –0.16, P = .01), organized football (β = 0.16, P = .01), and unsupervised trampoline jumping (β = 0.14, P = .04) were the strongest determinants of CRF, accounting altogether for 29.7% of variation in CRF.
These findings suggest that unsupervised physical activity is sufficient in improving CRF in both sexes. Furthermore, larger muscle mass and better balance are associated with higher CRF that has to be taken into account when assessing CRF using maximal cycle ergometer exercise test among children.
Jan Seghers, Ann-Sophie Van Hoecke, Astrid Schotte, Joke Opdenacker and Filip Boen
Self-efficacy has been found to be an important precondition for behavioral change in sedentary people. The current study examined the effectiveness and added value of including a 15-minute selfefficacy coaching at the start of a 12-week lifestyle physical activity (PA) program.
Participants were randomly assigned to a standard-intervention group (without additional self-efficacy coaching, N = 116) or extra-intervention group (with additional self-efficacy coaching, N = 111). Body mass index (BMI), cardiovascular fitness, self-reported PA, and self-efficacy beliefs were assessed at baseline and immediately after the intervention period. Perceived adherence to the PA program was assessed postintervention.
At posttest, a significant increase in cardiovascular fitness and decrease in BMI were found in both groups. Significant intervention effects emerged on PA behavior, self-efficacy, and program adherence, in favor of the extra-intervention group. Self-efficacy mediated the intervention effect on program adherence whereas no evidence was found for its role as mediator of PA change.
Adding a 15-minute self-efficacy coaching at the start of a lifestyle PA program is a promising strategy to enhance the intervention effects on PA behavior, self-efficacy beliefs, and program adherence. However, the role of self-efficacy as mediator of the intervention effect on in PA was not fully supported.
Roberta E. Rikli and C. Jessie Jones
The purpose of this study was to assess the reliability and validity of a 6-min walk test as a measure of physical endurance in older adults. Seventy-seven subjects, ages 60-87. performed three separate 6-min walk tests and a treadmill test and completed questionnaire items assessing physical activity level and functional status. The 6-min walk had good test-retest reliability (.88 <R < .94). particularly when a practice trial preceded the test trial. Convergent validity of the 6-min walk was demonstrated by its moderate correlation (.71 < r < .82) with treadmill performance. Construct validity was assessed by determining the ability of the test to detect differences between different age and activity level groups. As expected, walking scores decreased significantly across decades and were significantly lower for low-active subjects compared to high-active subjects. There was a moderate relationship between 6-min walk scores and self-reported functional ability. It was concluded that the 6-min walk can be used to obtain reasonably reliable and valid measures of physical endurance in older adults and that it moderately reflects overall physical functional performance.
Thomas W. Rowland
Performance in all forms of motor activity related to sport performance improves progressively during the course of the childhood years as a consequence of normal growth and development. Whether (a) sport training can accelerate and ultimately enhance this biological development and (b) the existence of certain ages when training might prove to be more effective in improving performance, particularly early in childhood, remains uncertain. Physiological adaptations to endurance training in prepubertal children (improvements in maximal oxygen uptake) are dampened compared with adults, but enhancements of strength following resistance training are equally effective at all ages. The extent that intensive training regimens characteristic of early sport specialization in children can trigger physiological and performance adaptations may therefore depend on the form of exercise involved. Clearly, additional research is needed to enhance the understanding of the physiological responses to intensive sport training in prepubertal individuals.