CCPT Performance Variables 53

Reaction Time

A one-way within subjects (or repeated measures) ANOVA was conducted to compare the effect of exercise intensity on reaction time post exercise. Reaction times were 311.17 ± 38.46ms, 284.31 ± 34.54ms, 279.66 ± 31.92ms and 275.23 ± 29.36ms for resting, low, moderate and high intensity, respectively. Mauchly´s test indicated that the assumption of sphericity had been violated (χ2_{(5) =}

24.40, p < 0.05); since the Greenhouse-Geissner estimate of sphericity (ε = .6) was closer to 1/(k - 1) than to 1, where k is the levels of conditions, degrees of freedom were corrected according the Huynh & Feldt estimate of sphericity (ε´ = .64). The overall results from the one-way repeated measures (within subjects) ANOVA showed that reaction time after running was significantly affected by Exercise Intensity F(1.91, 49.72) = 24.06, p < 0.005, ηp2 = 0.48. Observed power was 1.00. Polynomial trend analyses showed a significantly linear fashion of decrease in reaction time with exercise intensity F(1,26) = 42.66, p < 0.005, ηp2 = 0.62 with a power of 1.00. Bonferroni corrected pairwise comparisons indicated that reaction time in all three post conditions was significantly different from baseline values (p < 0.005). Moreover, reaction time after high intensity was also shown to be significantly different from the reaction time after low intensity running (p < 0.05). These results suggest that exercise intensity really does have an effect on reaction time after exercise. Specifically, the results suggest that reaction time decreases with exercise intensity in a linear, intensity dependent fashion.

Figure 26: Reaction Time post running

Note. The x-axis represents the 4 conditions, baseline, low intensity, moderate intensity and high intensity post running. On the y-axis reaction time is measured in milliseconds. The overall repeated-measures ANOVA was significant implying a linear decrease in reaction time with intensity and Bonferroni adjusted post-hoc measures indicated that reaction time at baseline was different from reaction time after low, moderate and high intensity. Moreover, low intensity was different from high intensity.

Commission Errors

A one-way within subjects (or repeated measures) ANOVA was conducted to compare the effect of exercise intensity on commission errors. Commission errors were 17.26 ± 6.78, 19.07 ± 7.90, 20.37 ± 7.99 and 19.00 ± 8.33 for resting, low, moderate and high intensity, respectively. Mauchly´s test indicated that the assumption of sphericity had not been violated (χ2(5) = 10.67, p > 0.05); therefore degrees of freedom were not corrected. The polynomial trend analyses showed a significant quadratic trend in the change of the commission errors F(1, 26) = 68.48, p < 0.05, ηp2 = 0.16 with a power of .56. However, the overall results from the one-way repeated measures (within subjects) ANOVA showed that commission errors were not significantly different after different exercise intensities F(3, 78) = 2.68, p > 0.05, ηp2 = 0.09. Observed power was .63. Bonferroni corrected post-hoc analyses confirmed this by indicating that there were no significant differences between any conditions (p > 0.05). These results suggest that there is a strong tendency that exercise intensity has an effect on inhibitory/executive control after running. Specifically, the results suggest that commission errors have a tendency to increase with exercise intensity in a linear, intensity dependent fashion. However,

Chapter 3 – Results ₅₅

the fact that the overall result of the used statistical model is only close to significance is likely due to low observed power.

Figure 27: Commission Error post running

Note. The x-axis represents the 4 conditions, baseline, low intensity, moderate intensity and high intensity post running. On the y-axis the amount of commission errors is shown. The overall repeated-measures ANOVA was close to significance.

Response Style

A one-way within subjects (or repeated measures) ANOVA was conducted to compare the effect of exercise intensity on response style. Response style values were 0.44 ± 0.40, 0.28 ± 0.22, 0.48 ± 0.38 and 0.29 ± 0.30 for resting, low, moderate and high intensity, respectively. Mauchly´s test indicated that the assumption of sphericity had been violated (χ2_{(5) = 17.92, p < 0.05); since the Greenhouse-}

Geissner estimate of sphericity (ε = .66) was as close to 1/(k - 1) as to 1, where k is the levels of conditions, the mean of the p-value for both, the Greenhouse-Geissner (ε = .66), and the Huynh & Feldt (ε´ = .71) estimates of sphericity to correct the degrees of freedom were taken into consideration. The overall results from the one-way repeated measures (within subjects) ANOVA showed that exercise intensity had a significantly effect on response style F(2.06, 53.50) = 3.63, p < 0.05, ηp2 = 0.12. Observed power was .65. Polynomial trend analyses showed a cubic trend F(1,26) = 18.42, p < 0.005, ηp2 = 0.42 with a power of .99. Bonferroni corrected pairwise comparisons indicated that response style was different after low and moderate intensity exercise (p < 0.05) and after moderate and high intensity (p < 0.05). These results suggest that exercise intensity has an effect on the construct of risky versus cautious behavior. Specifically, the results suggest that low and high intensity

led to a rather risky response style compared to the rather cautious response style after moderate intensity running.

Figure 28: Response Style post running

Note. The x-axis represents the 4 conditions, baseline, low intensity, moderate intensity and high intensity post running. On the y-axis a measure of response style is shown. The overall repeated-measures ANOVA was significant and Bonferroni adjusted post-hoc measures indicated that response style after low intensity running was different from the values after moderate intensity running. Moreover, response style after moderate intensity was different from the response style observed after high intensity running.

Perseverations

A one-way within subjects (or repeated measures) ANOVA was conducted to compare the effect of exercise intensity on perseveration errors. Perseveration errors were 0.48 ± 1.09, 2.04 ± 2.90, 2.33 ± 4.16 and 2.00 ± 2.75 for resting, low, moderate and high intensity, respectively. Mauchly´s test indicated that the assumption of sphericity had not been violated (χ2(5) = 10.23, p > 0.05); therefore degrees of freedom were not corrected. The overall result from the one-way repeated measures (within subjects) ANOVA showed that perseveration errors were significantly affected by exercise intensity F(3, 78) = 3.20, p < 0.05, ηp2 = 0.11. Observed power was .72. Polynomial trend analyses showed a significant linear fashion in the change of perseveration errors with increasing exercise intensity F(1,26) = 5.53, p < 0.05, ηp2 = 0.18 with a power of .62. Bonferroni adjusted, pairwise comparisons indicated that perseveration errors in none of the three post conditions were significantly different from either baseline (p > 0.05) or each other (p > 0.05). These results suggest that reaction times below 100ms (because of slow random, repetitive or anticipatory responses) were different after running. Specifically, the results suggest that perseveration errors increased in a linear fashion with

Chapter 3 – Results ₅₇

exercise intensity. However, the errors made after low, moderate and high intensity running were not specifically different from each other.

Figure 29: Perseveration post running

Note. The x-axis represents the 4 conditions, baseline, low intensity, moderate intensity and high intensity post running. On the y-axis the amount of perseveration errors is shown. The overall repeated-measures ANOVA was significant and Bonferroni adjusted post-hoc measures indicated no particular differences.

Reaction Time Block Change

A one-way within subjects (or repeated measures) ANOVA was conducted to compare the effect of exercise intensity on reaction time block change. Reaction time block change values were -0.0044 ± 0.017, 0.0074 ± 0.014, 0.0056 ± 0.016 and 0.011 ± 0.012 for resting, low, moderate and high intensity, respectively. Mauchly´s test indicated that the assumption of sphericity had not been violated (χ2_{(5) =}

1.21, p > 0.05); therefore degrees of freedom were not corrected. The overall result from the one-way repeated measures (within subjects) ANOVA showed that reaction time block change was significantly affected by Exercise Intensity F(3, 78) = 5.57, p < 0.005, ηp2 = 0.18. Observed power was .93. Polynomial trend analyses showed a significant linear increase in reaction time block change with increasing exercise intensity F(1,26) = 13.82, p < 0.005, ηp2 = 0.35 with a power of .95. Bonferroni corrected, pairwise comparisons indicated that reaction time block change at baseline was only significantly different from the values after high intensity exercising (p < 0.005). All other comparisons were not significantly different from one another (p > 0.05). These results suggest that the change in reaction time throughout the duration of the CCPT test was different after running.

Specifically, the results suggest that reaction time during the test slowed more after higher intensity running. Especially after high intensity the reaction time increased throughout the test more than in the other intensity conditions.

Figure 30: Reaction Time Block Change post running

Note. The x-axis represents the 4 conditions, baseline, low intensity, moderate intensity and high intensity post running. On the y-axis a measure of reaction time block change is shown. The overall repeated-measures ANOVA was significant and Bonferroni adjusted post-hoc measures indicated that reaction time block change at baseline was different from reaction time block change after high intensity running.

Reaction Time Standard Error Block Change

A one-way within subjects (or repeated measures) ANOVA was conducted to compare the effect of exercise intensity on reaction time standard error block change. Reaction time standard error block change values were 0.011 ± 0.084, 0.046 ± 0.055, 0.033 ± 0.063 and 0.057 ± 0.073 for resting, low, moderate and high intensity, respectively. Mauchly´s test indicated that the assumption of sphericity had not been violated (χ2_{(5) = 4.69, p > 0.05); therefore degrees of freedom were not corrected. The}

overall result from the one-way repeated measures (within subjects) ANOVA showed that reaction time standard error block change was significantly affected by Exercise Intensity F(3, 78) = 3.20, p < 0.05, ηp2 = 0.11. Observed power was .72. Polynomial trend analyses showed a significant linear increase in reaction time standard error block change with increasing exercise intensity F(1,26) = 5.37, p < 0.05, ηp2 = 0.17 with a power of .61. Bonferroni corrected, pairwise comparison indicated that reaction time standard error block change was not significantly different in any condition (p > 0.05). These results suggest that the change in response consistency during the time course of the test was

Chapter 3 – Results ₅₉

different after running. Specifically, the results suggest that response consistency got impaired in a linear fashion with intensity after running.

Figure 31: Reaction Time Standard Error Block Change post running

Note. The x-axis represents the 4 conditions, baseline, low intensity, moderate intensity and high intensity post running. On the y-axis a measure of reaction time standard error block change is shown. The overall repeated- measures ANOVA was significant and Bonferroni adjusted post-hoc measures indicated no particular differences.