The Influence of Fatigue on Trunk Motor Control and Brain Activity
Condition: Muscle Fatigue; Mental Fatigue; Event-related Potentials
MeSH terms: Fatigue; Mental Fatigue
Study type: Interventional

Summary: 
      This study aims at examining the influence of both physically and cognitively induced fatigue
      on trunk motor control on the one hand and brain activity related to movement preparation on
      the other hand, in healthy adult subjects. Furthermore, a comparison between the effects of
      both types of fatigue will be made. For this purpose a motor control task will be performed
      and compared before and after 3 specific interventions: i.e. a control intervention, a
      physical task and a cognitive task. Muscle and brain activity will be measured during each
      motor control task.

      It is hypothesised that motor control will not be altered after a control task, i.e. seated
      rest for 45 minutes. With regards to the physical fatigue condition, it is expected that
      trunk muscles will contract earlier after this task than before due to altered motor control.
      Cognitive fatigue is hypothesised to have similar underlying processes as physical fatigue,
      thus a similar earlier muscle contraction is also expected after cognitive fatigue.

      Lastly, as both types of fatigue are expected to induce a similar effect on motor control no
      significant differences between cognitive and physical fatigue are hypothesised. However, it
      is possible that the magnitude of this effect differs between types of fatigue, i.e. that 1
      of both types has a bigger effect on motor control than the other.

      With regards to brain activity in preparation of a motor control task similar hypotheses are
      formulated: no effect of the control task on brain activity, earlier and possibly increased
      brain activity after both fatiguing tasks, and no differences between both types of fatigue
      besides a possible difference in magnitude of effect.
    

Detailed description: 
      September 2016 - January 2017. 16 healthy, adult male and female participants aged 18-45 were
      tested for 3 conditions on 2 separate days, i.e. a control condition on test day 1; a
      physical and cognitive fatiguing condition in randomised order on test day 2.

      2 blocks of 80 rapid arm movements (RAM1 and RAM2) with the dominant arm were performed per
      condition, while electroencephalography (EEG) of the brain and surface electromyography
      (sEMG) of the Internal Oblique/Transversus Abdominis, External Oblique, Multifidus and
      Iliocostalis Lumborum pars Thoracis muscles were measured bilaterally. sEMG of the Anterior
      Deltoid muscle of the dominant arm was also measured. These RAM's were used to induce an
      internal perturbation to the postural balance of subjects and is an often used task in the
      study of trunk motor control. In between 2 blocks of the RAM the condition-specific
      interventions were given. The control condition consisted of RAM1 - 45 minute rest - RAM2;
      the physical fatigue condition consisted of RAM1 - 45 minute physical fatigue task - RAM2;
      the cognitive fatigue condition consisted of RAM1 - 45 minute cognitive fatigue task - RAM2.

      The physical fatiguing task was a static endurance task for the paravertebral muscles, i.e.
      modified Biering-Sörensen task, followed by a static endurance task for the abdominal
      muscles, i.e. a static abdominal curl in 45° of trunk flexion while seated.

      The cognitive fatiguing task was a modified incongruent Stroop color-word task for 45
      minutes.

      At the beginning of each test day several questionnaires were also administered to control
      for fatigue and physical activity, i.e. Checklist Individual Strength (CIS), Profile Of Mood
      States (POMS) and International Physical Activity Questionnaire (IPAQ).

      January - February 2018. an additional 6 subjects were tested in order to increase the sample
      size of this study.

      Statistical analysis will be performed to assess whether and to what extent both physical and
      cognitive fatigue might influence motor control as measured with EMG during RAM. Furthermore,
      the effect of both types of fatigue on cortical movement preparation will also be assessed
      based on the EEG measurements.
    

Intervention name(s): Control condition; Rapid Arm Movements; Physical fatigue condition; Cognitive fatigue condition
Intervention type(s): Behavioral; Behavioral; Behavioral; Behavioral
Intervention description(s): 45 minute rest while seated. Watching an animated movie, sleeping was not allowed.; 2 blocks of 80 trials of RAM in either a forward (n = 40) or backward (n = 40) shoulder flexion direction and back to neutral as fast as possible, with maintaining extension in the elbow. Visual cues (arrows) indicated the movement direction.; 40 minutes rest while seated followed by static endurance tasks, i.e. modified Biering-Sörensen task and static abdominal curl task.; 45 minutes of a cognitively fatiguing condition consisting of a modified incongruent Stroop color-word task.
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: Each participant will perform all 3 experimental conditions spread out over 2 test days. At test day 1 the control condition is performed. Test day 2 follows at least 5 days after the 1st one in order to make sure participants are physically and mentally recovered as the protocol at test day 1 might induce some physical or mental fatigue. On test day 2 the other 2 conditions are tested in a randomised order: either first the physical fatigue condition, followed by the cognitive fatigue condition or vice versa.
Masking: Single (Outcomes Assessor)
Primary purpose: Basic Science
Keywords: Sensorimotor control; Feedforward; Physical Fatigue; Cognitive Fatigue; Event-related potentials