Results for CBF & HR

Question 1

What were the main effects for heart rate observed in your study?

Answer 1

I found a significant main effect of time for heart rate, p < .001, ηp2 = 0.91 (large), indicating that heart rate increased from baseline to steady-state for both the SRC and HC groups.

Question 2

What were the main effects for MCAv observed in your study?

Answer 2

A significant main effect of time was also observed for middle cerebral artery velocity (MCAv), p < .001, ηp2 = 0.90 (large). This suggests that MCAv increased from baseline to steady-state for both the SRC and HC groups.

Question 3

What were the significant interactions found for heart rate in your study?

Answer 3

• I found a significant group by time interaction for heart rate, p = .048, ηp2 = 0.12 (medium). The SRC group showed a greater increase in heart rate from baseline to steady-state (54 bpm, SD = 17) compared to the HC group (42 bpm, SD = 14), p = .04, dz = 0.73 (medium)

Question 4

What were the significant interactions found for MCAv in your study?

Answer 4

A significant group by time interaction was also found for MCAv, F(1, 30) = 6.32, p = .018, ηp2 = 0.17 (large). The SRC group demonstrated a larger increase in MCAv from baseline to steady-state (38 cm/s, SD = 13) compared to the HC group (28 cm/s, SD = 10), t(30) = 2.51, p = .02, dz = 0.89 (large).

Question 5

What were the results of your correlation analyses between physiological and performance variables in your study?

Answer 5

• Pooled HC and SRC MCAv difference scores (steady-state minus baseline) were not significantly correlated with antisaccade reaction time (RT) difference scores, r(31) = -0.09, p = .59.
• Pooled HC and SRC heart rate difference scores were not significantly correlated with antisaccade RT difference scores, r(31) = -0.27, p = .13.
  However, pooled MCAv and heart rate difference scores were significantly correlated with steady-state exercise workload, r(31) = 0.55, p < 0.01 and r(31) = 0.36, p < 0.04, respectively, indicating that MCAv and heart rate increased with prescribed exercise intensity.

Question 6

Interpret Figure 2. What are the key takeaways regarding HR and MCAv and their difference scores?

Answer 6

• The red squares represent the group means for the SRC group, while the green triangles represent the group means for the HC group.
• The error bars indicate the 95% confidence intervals for the between-participant variability.
• The offset panels show baseline to steady-state MCAv differences between post- and pre-exercise for each group.
• If the error bars don’t cross the zero line, it indicates a reliable difference in RTs.
• Both HR and MCAv increased significantly from baseline to steady-state for the sport-related concussion (SRC) and healthy control (HC) groups. This is evident from the significant main effects of time for HR and MCAv, respectively. The main panel of Figure 2 also visually demonstrates this increase for both variables.
• There were significant group by time interactions for both HR and MCAv. This suggests that the increase in HR and MCAv from baseline to steady-state differed between the SRC and HC groups.
• The difference scores (steady-state minus baseline) for HR and MCAv were greater for the SRC group compared to the HC group. Specifically, the SRC group had a difference score of 54 bpm (SD = 17) for HR and 38 cm/s (SD = 13) for MCAv, while the HC group had a difference score of 42 bpm (SD = 14) for HR and 28 cm/s (SD = 10) for MCAv. These differences were statistically significant for HR and MCAv, respectively.

The smaller offset panels show the group mean difference scores and their associated 95% confidence intervals for HR and MCAv. The absence of overlap between the error bars and zero indicates a reliable difference, providing support for the significant group by time interactions and the larger increase in HR and MCAv for the SRC group compared to the HC group.