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Kent C. Kowalski, Peter R.E. Crocker and Nanette P. Kowalski

This study assessed the convergent validity of the Physical Activity Questionnaire for Adolescents (PAQ-A). The PAQ-A is a modified version for high school students of the Physical Activity Questionnaire for Older Children (PAQC). The PAQ-A is a 7-day recall used to assess general physical activity levels during the school year. Eighty-five high school students in Grades 8 through 12 filled out the PAQ-A and other physical activity measures. The PAQ-A was moderately related to an activity rating (r = .73), the Leisure Time Exercise Questionnaire (r = .57), a Caltrac motion sensor (r = .33), and the 7-day physical activity recall interview (r = .59). The results of this study support the convergent validity of the PAQ-A as a measure of general physical activity level for high school students.

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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.

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Orjan Ekblom, Gisela Nyberg, Elin Ekblom Bak, Ulf Ekelund and Claude Marcus

Background:

Wrist-worn accelerometers may provide an alternative to hip-worn monitors for assessing physical activity as they are easier to wear and may thus facilitate long-term recordings. The current study aimed at a) assessing the validity of the Actiwatch (wrist-worn) for estimating energy expenditure, b) determining cut-off values for light, moderate, and vigorous activities, c) studying the comparability between the Actiwatch and the Actigraph (hip-worn), and d) assessing reliability.

Methods:

For validity, indirect calorimetry was used as criterion measure. ROC-analyses were applied to identify cut-off values. Comparability was tested by simultaneously wearing of the 2 accelerometers during free-living condition. Reliability was tested in a mechanical shaker.

Results:

All-over correlation between accelerometer output and energy expenditure were found to be 0.80 (P < .001).Based on ROC-analysis, cut-off values for 1.5, 3, and 6 METs were found to be 80, 262, and 406 counts per 15 s, respectively. Energy expenditure estimates differed between the Actiwatch and the Actigraph (P < .05). The intra- and interinstrument coefficient of variation of the Actiwatch ranged between 0.72% and 8.4%.

Conclusion:

The wrist-worn Actiwatch appears to be valid and reliable for estimating energy expenditure and physical activity intensity in children aged 8 to 10 years.

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Kelly R. Evenson, Brian Neelon, Sarah C. Ball, Amber Vaughn and Dianne S. Ward

Background:

Despite the growing interest in active (ie, nonmotorized) travel to and from school, few studies have explored the measurement properties to assess active travel. We evaluated the criterion validity and test–retest reliability of a questionnaire with a sample of young schoolchildren to assess travel to and from school, including mode, travel companion, and destination after school.

Methods:

To assess test–retest reliability, 54 children age 8 to 11 years completed a travel survey on 2 consecutive school days. To assess criterion validity, 28 children age 8 to 10 years and their parents completed a travel survey on 5 consecutive weekdays.

Results:

test–retest reliability of all questions indicated substantial agreement. The questions on mode of transport, where you will go after school, and how you will get there also displayed substantial agreement between parental and child reports.

Conclusions:

For this population, a questionnaire completed by school-age children to assess travel to and from school, including mode, travel companion, and destination after school, was reliably collected and indicated validity for most items when compared with parental reports.

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Yaheli Bet-Or, Wolbert van den Hoorn, Venerina Johnston and Shaun O’Leary

explored. 1 , 13 , 14 The purpose of this study was to evaluate the reliability and validity of the AMC method in tracking scapular orientation at active end range clavicle protraction, retraction, elevation, and depression. Validity was evaluated by comparing AMC recordings to that of a scapular

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Sean P. Flanagan and George J. Salem

In the analysis of human movement, researchers often sum individual joint kinetics to obtain a single measure of lower extremity function. The extent to which these summed measures relate to the mechanical objectives of the task has not been formally validated. The criterion validity of these measures was established with comparisons to the mechanical objective of two multiple-joint tasks. For the Work task 18 participants performed a loaded barbell squat using 4 resistances while instrumented for biomechanical analysis. For the Power they performed 2 predetermined amounts of work at both self-selected and fast speeds. Using inverse dynamics techniques, the peak net joint moment (PM) was calculated bilaterally in the sagittal plane at the ankle, knee, and hip and was summed into a single measure. This measure was correlated with the task objectives using simple linear regression. Similar procedures were used for the average net joint moment (AM), peak (PP), and average (AP) net joint moment power, and the net joint moment impulse (IM) and work (IP). For the Work task all 6 measures were significantly correlated with the task objective, but only AM, PM, and IP had correlation coefficients above 0.90. For the Power task, IM was not significantly correlated with the task objective, and only AP had a correlation coefficient above 0.90. These findings indicate that the validity of summing individual kinetic measures depends on both the measure chosen and the mechanical objective of the task.

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Jose A. Rodríguez-Marroyo, Javier Medina-Carrillo, Juan García-López, Juan C. Morante, José G. Villa and Carl Foster

Purpose:

To analyze the concurrent and construct validity of a volleyball intermittent endurance test (VIET). The VIET’s test–retest reliability and sensitivity to assess seasonal changes was also studied.

Methods:

During the preseason, 71 volleyball players of different competitive levels took part in this study. All performed the VIET and a graded treadmill test with gas-exchange measurement (GXT). Thirty-one of the players performed an additional VIET to analyze the test–retest reliability. To test the VIET’s sensitivity, 28 players repeated the VIET and GXT at the end of their season.

Results:

Significant (P < .001) relationships between VIET distance and maximal oxygen uptake (r = .74) and GXT maximal speed (r = .78) were observed. There were no significant differences between the VIET performance test and retest (1542.1 ± 338.1 vs 1567.1 ± 358.2 m). Significant (P < .001) relationships and intraclass correlation coefficient (ICC) were found (r = .95, ICC = .96) for VIET performance. VIET performance increased significantly (P < .001) with player performance level and was sensitive to fitness changes across the season (1458.8 ± 343.5 vs 1581.1 ± 334.0 m, P < .01).

Conclusions:

The VIET may be considered a valid, reliable, and sensitive test to assess the aerobic endurance in volleyball players.

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Herbert Hatze

The validity and reliability of the jumping ergometer method for evaluating performance in two-legged vertical countermovement and serial rebound jumps were investigated. The internal segmental and nonvertical energy flow components for drop jumps were also studied. The exact dynamic equations governing the jumping motion in three dimensions were derived and used together with the approximate relations of the jumping ergometer method to evaluate a total of 72 vertical jumps of different types executed by 22 subjects (15 males, 7 females), average age 24.59 years. The force-plate method was selected as a reference procedure, to which the jumping ergometer results were related. For countermovement jumps, the relative error for jumping height was 3.55% (±2.92%), and for average power per kilogram body mass during the propulsion phase it was 23.79% (±4.85%). For serial rebound jumps, the respective errors were 7.40% (±4.58%) and 5.09% (±4.48%). Internal and nonvertical energy flow components amounted to about 3% of the total. It was concluded that, because of a number of invalid assumptions, unpredictable errors, and contradictory performance requirements, the validity and reliability of the jumping ergometer method for evaluating certain aspects of athletic performance are highly questionable.

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Nick Dobbin, Jamie Highton, Samantha L. Moss and Craig Twist

, discriminant validity) are required. 2 , 3 The majority of studies to date examining the anthropometric and physical characteristics of rugby league players have collected data from a single club with relatively small sample sizes. 11 , 14 , 16 These limitations could be addressed with a national standardized testing

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Greg Henry, Brian Dawson, Brendan Lay and Warren Young

Purpose:

To study the validity of a video-based reactive agility test in Australian footballers.

Methods:

15 higher performance, 15 lower performance, and 12 nonfootballers completed a light-based reactive agility test (LRAT), a video-based reactive agility test (VRAT), and a planned test (PLAN).

Results:

With skill groups pooled, agility time in PLAN (1346 ± 66 ms) was significantly faster (P = .001) than both reactive tests (VRAT = 1550 ± 102 ms; LRAT = 1572 ± 97 ms). In addition, decision time was significantly faster (P = .001; d = 0.8) in LRAT (278 ± 36 ms) than VRAT (311 ± 47 ms). The correlation in agility time between the two reactive tests (r = .75) was higher than between the planned and reactive tests (r = .41–.68). Higher performance players had faster agility and movement times on VRAT (agility, 130 ± 24 ms, d = 1.27, P = .004; movement, 69 ± 73 ms, d = 0.88, P = .1) and LRAT (agility, 95 ± 86 ms, d = 0.99, P = .08; movement, 79 ± 74 ms; d = 0.9; P = .08) than the nonfootballers. In addition, higher (55 ± 39 ms, d = 0.87, P = .05) and lower (40 ± 57 ms, d = 0.74, P = .18) performance groups exhibited somewhat faster agility time than nonfootballers on PLAN. Furthermore, higher performance players were somewhat faster than lower performance for agility time on the VRAT (63 ± 85 ms, d = 0.82, P = .16) and decision time on the LRAT (20 ± 39 ms, d = 0.66, P = .21), but there was little difference in PLAN agility time between these groups (15 ± 150 ms, d = 0.24, P = .8).

Conclusions:

Differences in decision-making speed indicate that the sport-specific nature of the VRAT is not duplicated by a light-based stimulus. In addition, the VRAT is somewhat better able to discriminate different groups of Australian footballers than the LRAT. Collectively, this indicates that a video-based test is a more valid assessment tool for examining agility in Australian footballers.