http://download.neurosky.com/docs/papers/bcq/Klimesch_1999_EEG_alpha_and_theta_oscillations_reflect_cognitive_and_memory_performance.pdf

EEG alpha and theta oscillations reflect cognitive and memory performance: a review and analysis

Muscle fatigue is an exercise-induced reduction in maximal voluntary muscle force. It may arise not only because of peripheral changes at the level of the muscle, but also because the central nervous system fails to drive the motoneurons adequately. Evidence for “central” fatigue and the neural mechanisms underlying it are reviewed, together with its terminology and the methods used to reveal it. Much data suggest that voluntary activation of human motoneurons and muscle fibers is suboptimal and thus maximal voluntary force is commonly less than true maximal force. Hence, maximal voluntary strength can often be below true maximal muscle force. The technique of twitch interpolation has helped to reveal the changes in drive to motoneurons during fatigue. Voluntary activation usually diminishes during maximal voluntary isometric tasks, that is central fatigue develops, and motor unit firing rates decline. Transcranial magnetic stimulation over the motor cortex during fatiguing exercise has revealed focal cha...

Spinal and Supraspinal Factors in Human Muscle Fatigue

Cognitive and biological determinants of P300: an integrative review

Background and Purpose. Treatment of patients with impingement symptoms commonly includes exercises intended to restore “normal” movement patterns. Evidence that indicates the existence of abnormal patterns in people with shoulder pain is limited. The purpose of this investigation was to analyze glenohumeral and scapulothoracic kinematics and associated scapulothoracic muscle activity in a group of subjects with symptoms of shoulder impingement relative to a group of subjects without symptoms of shoulder impingement matched for occupational exposure to overhead work. Subjects. Fifty-two subjects were recruited from a population of construction workers with routine exposure to overhead work. Methods. Surface electromyographic data were collected from the upper and lower parts of the trapezius muscle and from the serratus anterior muscle. Electromagnetic sensors simultaneously tracked 3-dimensional motion of the trunk, scapula, and humerus during humeral elevation in the scapular plane in 3 hand-held load conditions: (1) no load, (2) 2.3-kg load, and (3) 4.6-kg load. An analysis of variance model was used to test for group and load effects for 3 phases of motion (31°–60°, 61°–90°, and 91°–120°). Results. Relative to the group without impingement, the group with impingement showed decreased scapular upward rotation at the end of the first of the 3 phases of interest, increased anterior tipping at the end of the third phase of interest, and increased scapular medial rotation under the load conditions. At the same time, upper and lower trapezius muscle electromyographic activity increased in the group with impingement as compared with the group without impingement in the final 2 phases, although the upper trapezius muscle changes were apparent only during the 4.6-kg load condition. The serratus anterior muscle demonstrated decreased activity in the group with impingement across all loads and phases. Conclusion and Discussion. Scapular tipping (rotation about a medial to lateral axis) and serratus anterior muscle function are important to consider in the rehabilitation of patients with symptoms of shoulder impingement related to occupational exposure to overhead work.

https://ir.uiowa.edu/cgi/viewcontent.cgi?article=1000&context=oeh_pubs

Alterations in Shoulder Kinematics and Associated Muscle Activity in People With Symptoms of Shoulder Impingement

Measuring neurophysiological signals in aircraft pilots and car drivers for the assessment of mental workload, fatigue and drowsiness.

Muscular fatigue and action potential conduction velocity changes studied with frequency analysis of EMG signals.

The development of the electroencephalogram in normal children from the age of 1 through 15 years. Paroxysmal activity.

A new method for objective quantification of localized muscle fatigue is described. The method is based on power spectrum analysis of myoelectric signals obtained from the fatigued muscle. It permits real-time investigations and yields statistically based criteria for the occurrence of fatigue. The findings are interpreted in terms of muscle action potential conduction velocity changes and rate of the fatigue development.

An electromyographic index for localized muscle fatigue.

MORTIMER, J. THOMAS, ROBERT MAGNUSSON, AND INGEMAR PETERSON. Conduction velocity in ischemic muscle: effect or2 EMG frequency spectrum. Am. J. Physiol. 219(5): 1324-1329. 1970.-The action-potential conduction velocity in Yed” and “white” muscles was studied. The study was made by recording the conduction times during and following periods of repeated contractions while the muscle was ischemic or perfused with a dextran solution. During ischemia, repeated stimulation resulted in a continuous decay in the propagation velocity of the action potential. The decrease in conduction velocity is more pronounced in the gastrocnemius than in the soleus. The measured changes in conduction velocity are sufficient to account for changes in the EMG frequency spectrum noticed during muscle fatigue. Prolonged stimulation of a dextran-perfused muscle resulted in a significantly smaller change in conduction velocity than the change found in the ischemic experiment. It was concluded that maintenance of normal conduction velocity is dependent on the blood flow for removal of metabolic by-products and not for an energy supply. The metabolic by-product causing the velocity changes is suspected to be lactic acid.

Ingemar Petersén

Papers

Muscular fatigue and action potential conduction velocity changes studied with frequency analysis of EMG signals.

The development of the electroencephalogram in normal children from the age of 1 through 15 years. Paroxysmal activity.

An electromyographic index for localized muscle fatigue.

Conduction velocity in ischemic muscle: effect on EMG frequency spectrum.

Dynamic spectrum analysis of myo-potentials and with special reference to muscle fatigue.