Investigating the Inverted-U Relationship Between Cognitive Performance and Plasma Epinephrine

Study Overview
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Brief Summary
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Abstract Although acute resistance exercise has been suggested to enhance inhibitory control, a critical component of executive function, the mechanism by which acute exercise influences inhibitory control is unclear and there are methodological limitations in previous empirical studies. According to the locus coeruleus-norepinephrine (LC-NE) theory, the activity of the LC, the major releaser of NE in the brain, regulates inhibitory control. Because there is reciprocal communication between circulating epinephrine and the LC. Plasma epinephrine is chosen as the index of LC-NE activity. However, only one study in acute exercise-inhibitory control measured the plasma epinephrine. Therefore, this registered report aims to extend its findings by a four-arm crossover randomized controlled design with three different intensities, using free-weight, multiple-joint, and structural resistance exercises. Moreover, most studies showed some methodological limitations such as failing to report the process of randomization, implementing a familiarization of resistance exercise before the maximal strength test, and publishing the protocol. Without a transparent report on how the participants were allocated, the results were at risk of bias. Without a familiarization of resistance exercise, the maximal muscle strength was likely to be underestimated. Without publishing the protocol before data collection, these findings were threatened by undetected researchers' degrees of freedom such as HARKing (hypothesizing after the results are known), cherry picking, and p-hacking. This registered report will address the limitations of previous studies by incorporating cognitive and resistance exercise familiarization, transparently reporting the randomization process, and submitting it as a registered report.

Official Title
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Investigating the Inverted-U Relationship Between Cognitive Performance and Plasma Epinephrine: A Registered Report of a Four-arm Crossover Randomized Controlled Trial

Conditions
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Healthy Young Adults

Intervention / Treatment
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* Behavioral: Resistance exercise


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: healthy young male aged 18-40 years; recreational resistance-trained (≥ 1 time/week for the previous 6 months); free from cardiovascular, cerebrovascular, and neurological disorders and other chronic diseases; free from any medical condition listed on the 2014 update of the Physical Activity Readiness Questionnaire (PAR-Q+); non-smoker; and normal or corrected-to-normal vision. Exclusion Criteria: athlete trained in a competitive sports team or engaging in exercise for more than 20 hours/week; unable to perform any of the intervention exercises (barbell squat, press, and deadlift); or color blind

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 40 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| No Intervention: Control condition<br>During the control condition, participants will be asked to read a book related to exercise for approximately 40 minutes. | |
| Experimental: Low-intensity barbell resistance exercise<br>Exercise: Barbell squat, barbell press, and barbell deadlift Number of sets: 3 Number of repetitions: 5 Intensity: 65% 1RM Training method: Circuit training (Squat set 1 ➔ Press set 1 ➔ Deadlift set 1 ➔ Squat set 2 ➔ Press set 2 ➔ Deadlift set 2 ➔ Squat set 3 ➔ Press set 3 ➔ Deadlift set 3) Rest interval between exercises and sets:  3 minutes (Warm-up: 1 set of 5 repetitions for each exercise at 50% 1RM) | Behavioral: Resistance exercise<br>* There will be four conditions (three exercises and one control) on visits 3-6. For the three exercise conditions, all training parameters except intensity will be the same. The sets in high, moderate, and low intensity correspond to the rate of perceived exertion (0-10 scale) 7-9, 5-6, and 3-4, respectively. Therefore, the participants will perform 5 repetitions barbell squat, barbell press, and barbell deadlift with 8RM (78% 1RM), 11RM (72% 1RM), and 16RM (65% 1RM) for 3 sets<br>* Other names: Resistance training;|
| Experimental: Moderate-intensity barbell resistance exercise<br>Exercise: Barbell squat, barbell press, and barbell deadlift Number of sets: 3 Number of repetitions: 5 Intensity: 72% 1RM Training method: Circuit training (Squat set 1 ➔ Press set 1 ➔ Deadlift set 1 ➔ Squat set 2 ➔ Press set 2 ➔ Deadlift set 2 ➔ Squat set 3 ➔ Press set 3 ➔ Deadlift set 3) Rest interval between exercises and sets:  3 minutes (Warm-up: 1 set of 5 repetitions for each exercise at 50% 1RM) | Behavioral: Resistance exercise<br>* There will be four conditions (three exercises and one control) on visits 3-6. For the three exercise conditions, all training parameters except intensity will be the same. The sets in high, moderate, and low intensity correspond to the rate of perceived exertion (0-10 scale) 7-9, 5-6, and 3-4, respectively. Therefore, the participants will perform 5 repetitions barbell squat, barbell press, and barbell deadlift with 8RM (78% 1RM), 11RM (72% 1RM), and 16RM (65% 1RM) for 3 sets<br>* Other names: Resistance training;|
| Experimental: High-intensity barbell resistance exercise<br>Exercise: Barbell squat, barbell press, and barbell deadlift Number of sets: 3 Number of repetitions: 5 Intensity: 78% 1RM Training method: Circuit training (Squat set 1 ➔ Press set 1 ➔ Deadlift set 1 ➔ Squat set 2 ➔ Press set 2 ➔ Deadlift set 2 ➔ Squat set 3 ➔ Press set 3 ➔ Deadlift set 3) Rest interval between exercises and sets:  3 minutes (Warm-up: 1 set of 5 repetitions for each exercise at 50% 1RM) | Behavioral: Resistance exercise<br>* There will be four conditions (three exercises and one control) on visits 3-6. For the three exercise conditions, all training parameters except intensity will be the same. The sets in high, moderate, and low intensity correspond to the rate of perceived exertion (0-10 scale) 7-9, 5-6, and 3-4, respectively. Therefore, the participants will perform 5 repetitions barbell squat, barbell press, and barbell deadlift with 8RM (78% 1RM), 11RM (72% 1RM), and 16RM (65% 1RM) for 3 sets<br>* Other names: Resistance training;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Inhibitory control (change between baseline and 5 minutes after intervention/control) | The Inhibitory control (Stroop interference score) will be the mean incongruent reaction time minus the mean congruent reaction time. Lower scores mean a better outcome. | Baseline (before intervention) and 5 minutes after (post-task) intervention/control. | 
| Inhibitory control (change between baseline and 20 minutes after intervention/control) | The Inhibitory control (Stroop interference score) will be the mean incongruent reaction time minus the mean congruent reaction time. Lower scores mean a better outcome. | Baseline (before intervention) and 20 minutes after (post-task) intervention/control. | 
| Inhibitory control (change between baseline and 35 minutes after intervention/control) | The Inhibitory control (Stroop interference score) will be the mean incongruent reaction time minus the mean congruent reaction time. Lower scores mean a better outcome. | Baseline (before intervention) and 35 minutes after (post-task) intervention/control. | 
| Inhibitory control (change between baseline and 50 minutes after intervention/control) | The Inhibitory control (Stroop interference score) will be the mean incongruent reaction time minus the mean congruent reaction time. Lower scores mean a better outcome. | Baseline (before intervention) and 50 minutes after (post-task) intervention/control. | 
| Information processing speed (change between baseline and 5 minutes after intervention/control) | The Information processing speed will be the mean simple reaction time. Lower scores mean a better outcome. | Baseline (before intervention) and 5 minutes after intervention/control. | 
| Information processing speed (change between baseline and 20 minutes after intervention/control) | The Information processing speed will be the mean simple reaction time. Lower scores mean a better outcome. | Baseline (before intervention) and 20 minutes after intervention/control. | 
| Information processing speed (change between baseline and 35 minutes after intervention/control) | The Information processing speed will be the mean simple reaction time. Lower scores mean a better outcome. | Baseline (before intervention) and 35 minutes after intervention/control. | 
| Information processing speed (change between baseline and 50 minutes after intervention/control) | The Information processing speed will be the mean simple reaction time. Lower scores mean a better outcome. | Baseline (before intervention) and 50 minutes after intervention/control. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Epinephrine (change between baseline and immediately after intervention/control) | Plasma epinephrine concentrations will be measured in duplicate using a commercially available enzyme-linked immunosorbent assay (ELISA) kit. | Baseline and immediately after intervention/control. | 
| Epinephrine (change between baseline and 15 minutes after intervention/control) | Plasma epinephrine concentrations will be measured in duplicate using a commercially available enzyme-linked immunosorbent assay (ELISA) kit. | Baseline and 15 minutes after intervention/control. | 
| Epinephrine (change between baseline and 30 minutes after intervention/control) | Plasma epinephrine concentrations will be measured in duplicate using a commercially available enzyme-linked immunosorbent assay (ELISA) kit. | Baseline and 30 minutes after intervention/control. | 
| Epinephrine (change between baseline and 45 minutes after intervention/control) | Plasma epinephrine concentrations will be measured in duplicate using a commercially available enzyme-linked immunosorbent assay (ELISA) kit. | Baseline and 45 minutes after intervention/control. | 
| Epinephrine (change between baseline and 60 minutes after intervention/control) | Plasma epinephrine concentrations will be measured in duplicate using a commercially available enzyme-linked immunosorbent assay (ELISA) kit. | Baseline and 60 minutes after intervention/control. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Resistance Training, Kinesiology, Applied, Cognitive Neuroscience, Psychology, Sports, Cognitive Psychology, Psychophysiology, Exercise, Circuit-Based Exercise