Pat R. Vehrs

VO2max estimation from a submaximal 1-mile track jog for fit college-age individuals.

The primary purpose of this study was to develop a submaximal field test for the estimation of maximal oxygen uptake (VO2max) using a 1-mile track jog. A second purpose was to determine the accuracy of the 1.5-mile run in estimating VO2max for both male and female subjects. VO2max was measured in 149 relatively fit college students (males = 88, females = 61) 18-29 yr using a treadmill protocol (mean +/- SD; VO2max = 47.7 +/- 6.3 ml.kg-1 x min-1). Multiple regression analysis (N = 54) to estimate VO2max from the submaximal, steady-state 1-mile track jog yielded the following validation (V) model (r(adi) = 0.87, SEE = 3.0 ml.kg-1 x min-1): VO2max = 100.5 + 8.344* GENDER (0 = female; 1 = male) - 0.1636* BODY MASS (kg) - 1.438* JOG TIME (min.mile-1) - 0.1928* HEART RATE (bpm). To help ensure that a submaximal level of exertion was realized for the 1-mile track jog, elapsed jog time was restricted to > or = 8.0 min for males and > or = 9.0 min for females and exercise HR to < or = 180 bpm. Cross-validation (CV) of the 1-mile track jog comparing observed and estimated VO2max (N = 52) resulted in radj = 0.84, SEE = 3.1 ml.kg-1 x min-1. Multiple regression analysis (N = 50) to estimate VO2max from the 1.5-mile run (V:N = 49, radj = 0.90, SEE = 2.8 ml.kg-1 x min-1; CV: N = 47, radj = 0.82, SEE = 3.9 ml.kg-1 x min-1), used elapsed run time, body mass, and gender as independent variables.(ABSTRACT TRUNCATED AT 250 WORDS)

An Accurate VO2max Nonexercise Regression Model for 18–65-Year-Old Adults

Abstract The purpose of this study was to develop a regression equation to predict maximal oxygen uptake (VO2max) based on nonexercise (N-EX) data. All participants (N= 100), ages 18–65 years, successfully completed a maximal graded exercise test (GXT) to assess VO2max (M= 39.96 mL·kg -1· min -1 , SD = 9.54). The N-EX data collected just before the maximal GXT included the participants age; gender; body mass index (BMI); perceived functional ability (PFA) to walk, jog, or run given distances; and current physical activity (PA-R) level. Multiple linear regression generated the following N-EX prediction equation (R = .93, SEE = 3.45 mL·kg -1· min -1 , %SEE= 8.62): VO2max (mL·kg -1· min -1 ) = 48.0730 + (6.1779 x gender; women = 0, men = 1) – (0.2463 x age) – (0.6186 x BMI) + (0.7115 x PFA) + (0.6709 x PA-R). Cross validation using PRESS (predicted residual sum of squares) statistics revealed minimal shrinkage (R p = .91 and SEE p = 3.63 mL·kg -1· min -1 ); thus, this model should yield acceptable accuracy when applied to an independent sample of adults (ages 18–-65 years) with a similar cardiorespiratory fitness level. Based on standardized β-weights, the PFA variable (0.41) was the most effective at predicting VO2max followed by age (-0.34), gender (0.33), BMI (-0.27), and PA-R (0.16). This study provides a N-EX regression model that yields relatively accurate results and is a convenient way to predict VO2max in adult men and women.

Aerobic and resistance exercise sequence affects excess postexercise oxygen consumption.

Excess postexercise oxygen consumption (EPOC) may describe the impact of previous exercise on energy metabolism. Ten males completed Resistance Only, Run Only, Resistance-Run, and Run-Resistance experimental conditions. Resistance exercise consisted of 7 lifts. Running consisted of 25 minutes of treadmill exercise. VO2 was determined during tread-mill exercise and after each exercise treatment. Our findings indicated that treadmill exercise VO2 was significantly higher for Resistance-Run compared with Run-Resistance and Resistance Only at all time intervals. At 10 minutes postexercise, VO2 was greater for Resistance Only and Run-Resistance than for Resistance-Run. At 20 and 30 minutes, VO2 following Resistance Only was significantly greater than following Run Only. In conclusion, EPOC is greatest following Run-Resistance; however, treadmill exercise is more physiologically difficult following resistance exercise. Furthermore, the sequence of resistance and treadmill exercise influences EPOC, primarily because of the effects of resistance exercise rather than the exercise combination. We recommend performing aerobic exercise before resistance exercise when combining them into 1 exercise session.

Development of a submaximal treadmill jogging test for fit college-aged individuals.

The purpose of this study was to develop a single-stage submaximal treadmill jogging test for the estimation of maximal oxygen uptake (VO2max). VO2max was measured in 129 relatively fit individuals (males = 84, females = 45), 18-29 yr, using a maximal treadmill protocol (mean +/- SD; VO2max = 48.3 +/- 6.2 ml.kg-1 x min-1, range = 35.6 to 62.3 ml.kg-1 x min-1). The treadmill test required subjects to sustain a comfortable, submaximal jogging pace (4.3-7.5 mph; level grade) until a steady-state heart rate was achieved (approximately 3 min). To help ensure that a submaximal level of exertion was realized for the treadmill jogging test, treadmill speed and exercise HR criteria were established that restricted treadmill speed to < or = 7.5 mph for males and < or = 6.5 mph for females and steady-state exercise HR < or = 180 bpm. Multiple regression analysis (N = 66) to estimate VO2max from the treadmill jogging test yielded the following validation (V) model (r(adj) = 0.84, SEE = 3.2 ml.kg-1 x min-1): VO2max = 54.07 + 7.062 * GENDER (0 = female; 1 = male) - 0.1938 * WEIGHT (kg) + 4.47* SPEED (miles.h-1) - 0.1453 * HEART RATE (bpm). Cross-validation (CV) of the treadmill jogging test comparing observed and estimated VO2max (N = 63) resulted in r(adj) = 0.88, SEE = 3.1 ml.kg-1 x min-1. The results indicate that this submaximal single-stage treadmill jogging test based on multiple linear regression provides a valid and convenient method for estimating VO2max.

Reliability of 16 Balance Tests in Individuals with down Syndrome

To assess test-retest reliability scores on 16 balance tests of 21 individuals with Down syndrome whose ages ranged from 5 to 31 yr., participants performed a standing test on firm and soft surfaces with the eyes open and closed, the balance subset of the Bruininks-Oseretsky test, full turn, timed-up-and-go test, forward reach, and sit-to-stand. Each participant completed all 16 tests twice in one day and then again on a subsequent day for a total of 4 sessions. The interclass reliability correlation coefficients (ICC) value for each measure of balance varied considerably by age and sex. Based on having an ICC > .50, only 3 tests were reliable in young males and young females, whereas 5 tests could reliably be used in adult females and 9 tests could reliably be used in adult males. The results of this study raise suspicions as to the reliability of tests commonly used to assess balance and differences in reliability due to age and sex. Results of balance tests should be interpreted with caution in males and females with Down syndrome across the age span.

Development of a Notational Analysis System for Selected Soccer Skills of a Women's College Team

The purposes of this study were to develop a notational system to evaluate passing, dribbling, first touch, and individual defensive skills as they relate to success during womens soccer games and to develop a statistical model to weigh the importance of each skill on creating scoring opportunities. Sequences of skills in ten games of a National Collegiate Athletic Association Division I intercollegiate womens soccer team were coded using well defined performance scores and outcomes. The notational analysis system was highly reliable as demonstrated by Spearmans rank correlations (>.98) between the first and second notation of three games for all four skills. The importance scores calculated from a Bayesian model demonstrated that dribbling (.0127) was the most important skill on creating scoring opportunities, followed by first touch (.0079), passing (.0075), and individual defense (.0050). The notational system developed from this study provides coaches with reliable and objective information to improve practice planning and optimize performance.

Submaximal Treadmill Exercise Test to Predict VO2max in Fit Adults

This study was designed to develop a single-stage submaximal treadmill jogging (TMJ) test to predict VO2max in fit adults. Participants (N = 400; men = 250 and women = 150), ages 18 to 40 years, successfully completed a maximal graded exercise test (GXT) at 1 of 3 laboratories to determine VO2max. The TMJ test was completed during the first 2 stages of the GXT. Following 3 min of walking (Stage 1), participants achieved a steady-state heart rate (HR) while exercising at a comfortable self-selected submaximal jogging speed at level grade (Stage 2). Gender, age, body mass, steady-state HR, and jogging speed (mph) were included as independent variables in the following multiple linear regression model to predict VO2max (R = 0.91, standard error of estimate [SEE] = 2.52 mL · kg−1 · min−1): VO2max (mL · kg−1 · min−1) = 58.687 + (7.520 × Gender; 0 = woman and 1 = man) + (4.334 × mph) − (0.211 × kg) − (0.148 × HR) − (0.107 × Age). Based on the predicted residual sum of squares (PRESS) statistics (RPRESS = 0.91, SEE PRESS = 2.54 mL · kg−1 · min−1) and small total error (TE; 2.50 mL · kg−1 · min−1; 5.3% of VO2max) and constant error (CE; −0.008 mL · kg−1 · min−1) terms, this new prediction equation displays minimal shrinkage. It should also demonstrate similar accuracy when it is applied to other samples that include participants of comparable age, body mass, and aerobic fitness level. This simple TMJ test and its corresponding regression model provides a relatively safe, convenient, and accurate way to predict VO2max in fit adults, ages 18 to 40 years.

A Modified Submaximal Cycle Ergometer Test Designed to Predict Treadmill VO2max

This study sought to develop a modified submaximal cycle ergometer test designed to predict maximal oxygen consumption (VO2max) obtained on a treadmill. Volunteers (N = 156; women = 80, men = 76) with ages from 18 to 39 years old successfully performed a submaximal cycle protocol on a stationary cycle ergometer and a maximal graded exercise test (GXT) on a treadmill. Open circuit calorimetry was used during the GXT to measure VO2max. Multiple linear regression resulted in the following prediction equation: VO2max = 85.447 + 9.104 χSex (0 = women; 1 = men) - 0.2676 χAge (year) - 0.4150 χBody Mass (kg) + 0.1317 χPower Output (W) - 0.1615 χHeart Rate (bpm), which had acceptable validity (r = .88, standard error of estimate [SEE] = 3.12 ml· kg-1 · min-1). Selected participants (n = 34) performed the submaximal cycle ergometer test twice (within a 5-day period), yielding a test-retest intraclass reliability coefficient of r = .95 for VO2max estimations across days. The reliability of VO2max estimates for women (r = .93) was greater than that for men (r = .74). Cross-validation results were also acceptable using predicted residual sum of squares (PRESS; rPRESS = .87, SEEPRESS = 3.24 ml · kg-1 min-1), which suggests that the new equation should yield acceptable accuracy when it is applied to a similar, but independent sample of adults. In summary, the modified cycle ergometer test developed in this study yields relatively accurate estimates of treadmill VO2max in young adults, requires only a moderate level of exertion, and appears to be a convenient and time-efficient means of estimating cardiorespiratory fitness.

Water treadmill parameters needed to obtain land treadmill intensities in runners.

PURPOSE To establish water treadmill running parameters with shoes (WTR-S) and without water shoes (WTR-NS) needed to obtain known land treadmill running (LTR) cardiorespiratory responses. METHODS Eighteen trained college-aged runners participated in three running conditions (LTR, WTR-S, and WTR-NS) where cardiorespiratory responses were measured. The primary variables of interest were VO2, HR, treadmill speed, and stride frequency (SF). These variables were assessed at 50%, 60%, 70%, and 80% equivalents of land VO2max for all three running conditions. RESULTS Data were centered; so in the analysis, intercepts were calculated within the range of data. At an HR of 150 bpm, VO2 was significantly less (P < 0.05) during LTR (34.6 mL·kg(-1)·min(-1)) compared with WTR-S (37.5 mL·kg(-1)·min(-1)) and WTR-NS (37.2 mL·kg(-1)·min(-1)). HR was approximately 7 bpm less during WTR compared with LTR, although the metabolic demand (VO2) was similar. At a treadmill speed of 160.9 m·min(-1), SF during LTR was 23.6 strides per minute greater (P < 0.05) than that during WTR-S and 21.8 strides per minute greater than that during WTR-NS. Wearing water shoes increased VO2 by 4.12 mL·kg(-1)·min(-1) at any given water treadmill speed. CONCLUSIONS To achieve metabolic oxygen demands equivalent to intensities from 50% to 80% of VO2max on LTR, WTR parameters have to be changed from those used on LTR. WTR is an effective alternative to LTR. Subjects were able to exercise on the water treadmill at intensities equivalent to 80% of their VO2max and 55% to 94% of their land HRmax. Individuals can select a treadmill speed during WTR that elicits an HR of approximately 7 bpm less than their LTR to obtain a cardiorespiratory overload equivalent to 50%, 60%, 70%, and 80% of their land VO2max.

A Maximal Graded Exercise Test to Accurately Predict VO2max in 18–65-Year-Old Adults

The purpose of this study was to develop an age-generalized regression model to predict maximal oxygen uptake (VO2max) based on a maximal treadmill graded exercise test (GXT; George, 1996). Participants (N = 100), ages 18–65 years, reached a maximal level of exertion (mean ± standard deviation [SD]; maximal heart rate [HRmax] = 185.2 ± 12.4 beats per minute (bpm); maximal respiratory exchange ratio [RERmax] = 1.18 ± 0.05; maximal rating of perceived exertion (RPEmax) = 19.1 ± 0.7) during the GXT to assess VO2max (mean ± SD; 40.24 ± 9.11 mL·kg−1·min−1). Multiple linear regression generated the following prediction equation (R = .94, standard error of estimate [SEE] = 3.18 mL·kg−1·min−1, %SEE = 7.9): VO2max (mL·kg−1·min−1) = 13.160 + (3.314 × gender; females = 0, males = 1) − (.131 × age) − (.334 × body mass index (BMI)) + (5.177 × treadmill speed; mph) + (1.315 × treadmill grade; %). Cross validation using predicted residual sum of squares (PRESS) statistics revealed minimal shrinkage (Rp  = .93 and SEE p  = 3.40 mL·kg−1·min−1); consequently, this model should provide acceptable accuracy when it is applied to independent samples of comparable adults. Standardized β-weights indicate that treadmill speed (.583) was the most effective at predicting VO2max followed by treadmill grade (.356), age (−.197), gender (.183), and BMI (−.148). This study provides a relatively accurate regression model to predict VO2max in relatively fit men and women, ages 18–65 years, based on maximal exercise (treadmill speed and grade), biometric (BMI), and demographic (age and gender) data.