William D. McArdle

Reliability and interrelationships between maximal oxygen intake, physical work capacity and step-test scores in college women

The interrelationships between maxVo2, PWC and Skubic-Hodgkins recovery heart rate test scores were determined in 41 college women (6 athletes, 35 untrained). Test-retest reliability of maxVo2, and of physical work capacity scores on a treadmill test was also determined. In addition, reliability and validity were obtained for a 3-min step test which the authors have successfully used in evaluating and grouping large numbers of college women. The Balke treadmill test for eliciting maxVo2 provides a highly reproducible (r = .95; V1 = 2,22, X2= 2.25 1 02/min) means for assessing aerobic capacity in women. Reliability of step test scores and various PWC measures ranged from r = .78 to .92. The highest validity correlation (r = -.75) was obtained between maxVo2, (ml/kg.min) and the 5 to 20 sec recovery heart rate from a 3-min step test of moderate intensity (161/4“ bench; 22 steps/min; ± H.R. = 152 beats/min). One standard error of prediction from the regression line was ± 2.9 ml O2 which was, on the average, within ± 8% of actual maxVo2 values. This was lower than the standard errors obtained using Skubic-Hodgkins, PWC150, PWC170 or PWCmax to predict maxVo2.

Comparison of continuous and discontinuous treadmill and bicycle tests for max Vo2.

ABSTRACTThe max VO2 and associated physiologic measures were compared in 15 male college students by use of the following six discontinuous and continuous bicycle ergometer and treadmill tests: Discontinuous Bicycle (DB), Continuous Bicycle (CB), Discontinuous Treadmill (DT), Continuous Treadmill (

Physical work capacity and maximum oxygen uptake in treadmill and bicycle exercise

The metabolic, heart rate and ventilatory patterns and physical work capacity in bicycle and treadmill exercise were compared in 23 male college students. The average reduction in max Vo2 of .324 l/min (9.9%) observed during bicycle work was highly significant (P < 0.01). The standard error of the prediction for max Vo2 on the treadmill from observed values on the bicycle ergometer was ± .291 l/min (r=0.82). Minute ventilatory volume was similar at all measured work levels in both forms of exercise with the respiratory exchange ratio being significantly higher on the bicycle at submaximal heart rates and at max Vo2 A significantly larger percentage of the max Vo2 was elicited at submaximal heart rates on the bicycle when compared to similar heart rates on the treadmill. At max Vo2 the heart rate was significantly lower in the bicycle test. PWC150 and PWC170 on the bicycle ergometer correlated fairly well with similar measures on the treadmill. However, when PWCmax was compared in both tests the relationship was significantly reduced (r=0.34). PWC on the bicycle was favored more by a high absolute max Vo2 (l/min), whereas the relative max Vo2 (ml/kg/min) was highly related to treadmill exercise. This was particularly demonstrated at PWCmax on the treadmill with work capacity correlating r=0.92 and r=0.37 with relative and absolute max Vo2, respectively. However, when the effect of body weight was held statistically constant the partial correlation between max Vo2 (l/min) and PWCmax on the treadmill increased to r12.3=0.91. Expressing the oxygen uptake in terms of lean body weight did not improve its relationship to PWC on the bicycle or treadmill.

Thermal responses of men and women during cold-water immersion: influence of exercise intensity.

SummaryThe influence of exercise intensity on thermoregulation was studied in 8 men and 8 women volunteers during three levels of arm-leg exercise (level I: 700 ml oxygen (O2) · min−1; level II: 1250 ml O2 · min−1; level III: 1700 ml O2 · min−1 for 1 h in water at 20 and 28°C (Tw). For the men inTw 28°C the rectal temperature (Tre) fell 0.79°C (P<0.05) during immersion in both rest and level-I exercise. With level-II exercise a drop inTre of 0.54° C (P < 0.05) was noted, while at level-III exerciseTre did not change from the pre-immersion value. AtTw of 20°C,Tre fell throughout immersion with no significant difference in finalTre observed between rest and any exercise level. For the women at rest atTw 28°C,Tre fell 0.80°C (P<0.05) below the pre-immersion value. With the two more intense levels of exercise,Tre did not decrease during immersion. InTw 20°C, the women maintained higherTre (P<0.05) during level-II and level-III exercise compared to rest and exercise at level I. TheTre responses were related to changes in tissue insulation (It) between rest and exercise with the largest reductions inIt noted between rest and level-I exercise acrossTw and gender. For men and women of similar percentage body fat, decreases inTre were greater for the women at rest and level-I exercise inTw 20°C (P< 0.05). With more intense exercise, the women maintained a higherTre than the men, especially in the colder water. These findings indicate that exercise is not always effective in offsetting the decrease inIt and facilitated heat loss in cool or cold water compared to rest. The factors of exercise intensity,TW, body fat, and gender influence the thermoregulatory responses.

Cardiovascular adjustments to exercise distributed between the upper and lower body

The present study examined the hemodynamic differences between upper- and lower-body exercise where the total power output (PO) was proportionally distributed between the upper and lower body. Six males completed five combinations of arm-leg exercise at maximal and three submaximal intensities. The ratio of arm PO to total PO for each exercise combination was 0, 25, 50, 75, and 100%. At each submaximal intensity, VO2 and cardiac output (Q) were not different (P greater than 0.05) across exercise combinations. Likewise, heart rate (HR) responses were not different for 0, 25, 50, and 75% at level 1 (mean = 102, 102, 106, 106 beats.min-1, respectively), level 2 (mean = 114, 110, 119, 118 beats.min-1, respectively), and level 3 (mean = 127, 124, 132, 131 beats.min-1, respectively). However, HR for 100% (arm-only exercise) tended to be higher than 0% at level 1 (delta HR = 10 beats.min-1; P less than 0.10), level 2 (delta HR = 12 beats.min-1, P less than 0.06) and level 3 (delta HR = 10 beats.min-1; P less than 0.06). At level 1, stroke volume (SV) remained essentially unchanged from 0-75%, while SV at 100% (108 ml) was slightly though not significantly lower (P less than 0.10) than 0% (125 ml). At exercise levels 2 and 3, SV remained unchanged for 0 and 25%; however, SV at 50, 75, and 100% were generally lower (P less than 0.05) compared with 0%. These results indicate that involving the leg musculature to varying degrees during arm-leg exercise attenuates the hemodynamic differences observed during strict upper body versus strict lower body exercise.

Specificity of arm training on aerobic power during swimming and running.

The specificity of aerobic training for upper-body exercise requiring differing amounts of muscle mass was evaluated in 25 college-aged male recreational swimmers who were randomly assigned to either a non-training control group (N = 9), a 10-wk swim(S)-training group (N = 9), or a group that trained with a standard swim-bench pulley system (SB; N = 7). For all subjects prior to training, tethered-swimming peak VO2 averaged 19% below treadmill values (P less than 0.01), while SB-ergometry peak VO2 was 50% and 39% below running and swimming values, respectively (P less than 0.01). Significant (P less than 0.01) increases of peak VO2 in tethered swimming (11%) and SB (21%) were observed for the SB-trained group, while the S-trained group improved (P less than 0.01) 18% and 19% on the tethered swimming and SB tests, respectively. No changes were observed during treadmill running, and the control subjects remained unchanged on all measures. Comparisons between training groups indicated that although both groups improved to a similar extent when measured on the swim bench, the 0.53 l X min-1 improvement in tethered-swimming peak VO2 for the S-trained group was greater (P less than 0.05) than the 0.32 l X min-1 increase noted for the SB-trained group. The comparisons between SB and S exercise vs treadmill exercise support the specificity of aerobic improvement with training and suggest that local adaptations contribute significantly to improvements in peak VO2. Furthermore, the present data indicate that SB exercise activates a considerable portion of the musculature involved in swimming, and that aerobic improvements with SB training are directly transferred to swimming.

Aerobic Capacity, Heart Rate and Estimated Energy Cost during Women's Competitive Basketball

Abstract In the present study the relative strenuousness of womens competitive basketball was evaluated in six members of the Queens College womens basketball team by use of the telemetered heart rate. Heart rates were obtained on each subject for at least one quarter during regularly scheduled games. Estimates of energy expenditure were obtained by applying each subjects activity heart rate to her heart rate-oxygen uptake curve established in the laboratory. Since the rules of womens basketball are in a state of change, measurements were obtained in both 5- and 6-player competition. In addition, changes in aerobic capacity over the season were evaluated by use of the maximum oxygen uptake test. It was concluded that: (a) Mean changes in body weight, Max [Vdot]O2, and maximum heart rate during the basketball season were not statistically significant. (b) Under playing conditions (actual play, out-of-bounds and foul shots) average heart rates ranged from 154 beats/min for a guard in a 6-player game to ...

Maximal Oxygen Intake, Endurance Running Performance, and Body Composition in College Women

Abstract The purpose of the present study was to determine the validity of Coopers 12-min. endurance run test in 36 college women using max VO2 as the criterion of validity. Max VO2 was measured using the Balke treadmill test (mean = 2.29 L/min; 38.9 ml/kg/min). Percent body fat (mean = 21.8%) and lean body weight (mean = 45.0 kg.) were also determined in 17 women from body density measurements (underwater weighing). A significant correlation of r = .67 was obtained between the endurance run and max VO2 (ml/kg/min), which increased to r = .71 when the correlation was corrected for attenuation from test unreliability in max VO2 (r 11 = .95) and the run (r 22 = .78). One standard error for predicting max VO2 from the run scores was within ± 9% (3.4 ml/kg) and ± 13% (299 ml/min) of predicted values, respectively. Coopers regression equation to predict max VO2 from the run scores in men underestimated the average max VO2 in women by 18%. Lean body weight correlated r = .49 with the run scores and r = .76 wi...

Validity of the postexercise heart rate as a means of estimating heart rate during work of varying intensities.

Abstract To determine the validity of the postexercise heart rate as a means of estimating the rate during work, heart rate was recorded at various intervals during recovery from light, moderate, and strenuous work. The error in estimating the exercise heart rate from readings taken during the 10 seconds immediately following strenuous work (180 beats/min.) averaged 2.7%. This increased to 7.6% during the first 10 seconds of recovery from exercise rates of approximately 140 beats / min. If one allowed approximately 4 seconds to locate the pulse and then counted during a 10-second interval, the average underestimation of the exercise heart rate increased to 5.7% in strenuous work and 13.5% in recovery from more moderate exercise. The rate of recovery is not similar for all individuals. This variability may introduce serious errors when the postexercise heart rate is used to infer the heart rate during exercise.

Relationship between Individual Differences in a Steady Pace Endurance Running Performance and Maximal Oxygen Intake

Abstract The relationship between individual differences in a steady-pace endurance running test and maximal oxygen intake (L/min., ml/kg·min, ml/kg LBW·min) was determined in 25 college men. In the running test subjects attempted to maintain an initial running speed of 10 mph (4.89 yd/sec) for 10 min. as they were paced around a 440-yd. track. Running performance was scored as running time between consecutive sections of the track, and an endurance score was calculated as the cumulated distance run during each minute. Max VO2 (ml/kg-min) correlated r = .61 with cumulative distance after 5 min. of running. Validity correlations were only slightly increased by including minutes 8 to 10. Expressing max VO2 in either L/min. or ml/kg LBW·min did not improve the correlation. Percent drop-off in running speed from the initial pace averaged 16% at minute 5 and 31% at minute 10. Body weight and percent body fat were inversely correlated with 10 min. of cumulative performance (r = -.33 and -.43, respectively). At ...