The present study examined the association between personality, competitive anxiety, somatic anxiety and physiological arousal in athletes with high and low anxiety levels. Anxiety was manipulated by means of an incentive. Fifty male participants, first, completed the Five Factor Personality Inventory and their resting electro dermal activity (EDA) was recorded. In the second stage, participants were randomly assigned to high or low anxiety groups. Individual EDAs were recorded again to determine precompetition physiological arousal. Participants also completed the Competitive State Anxiety Inventory-2 (CSAI-2) and played a computer-simulated soccer match. Results showed that neuroticism was related to both CSAI-2 components and physiological arousal only in the group receiving the incentive. Winners had higher levels of cognitive anxiety and lower levels of physiological arousal than losers. On the basis of these findings, we concluded that an athlete’s neurotic personality may influence his cognitive and physiological responses in a competition.

This study examines the relationship between psychophysiological arousal, cognitive anxiety, and personality traits in young taekwondo athletes. A total of 20 male and 10 female taekwondo athletes (mean age = 18.6 years; ± 1.8) volunteered for the study. The Five Factor Personality Inventory and the state scale of the Spielberger State-Trait Anxiety Inventory (STAI) were used to measure personality and cognitive state anxiety. Electrodermal activity (EDA) was measured twice, one day and approximately one hour prior to the competition, to determine psychophysiological arousal. Descriptive statistics, Pearson product-moment correlations, and stepwise regression were used to analyze the data. Several “Big Five” facets were related to the EDA delta scores that were measured both one day and one hour before the competition. Two stepwise regressions were conducted to examine whether personality traits could significantly predict both EDA delta scores. The final model, containing only neuroticism from the Big Five factors, can significantly explain the variations in the EDA delta scores measured one day before the competition. Agreeableness can significantly explain variations in the EDA delta scores measured one hour before the competition. No relationship was found between cognitive anxiety and the EDA delta scores measured one hour before the competition. In conclusion, personality traits, especially agreeableness and neuroticism, might be useful in understanding arousal responses to competition.

We investigated the effect of verbal encouragement on maximal voluntary contraction (MVC) level of the triceps surae muscle group. Our secondary focus was to examine whether the effect of verbal encouragement on MVC level varies as a result of conscientiousness. While the participants performed plantar flexion, MVCs of the triceps surae muscle group were measured using rectified and smoothed surface electromyography (rsEMG) during the absence and presence of verbal encouragement. Participants completed questions from the Five Factor Personality Inventory concerning conscientiousness and were divided into high- and low-conscientiousness groups according to a median split. The sample included 30 female and 53 male elite athletes. In the entire cohort, there was no significant difference in MVCs with and without verbal encouragement. When the sample was partitioned by conscientiousness scores, verbal encouragement led to a significant increase in MVC in the low-conscientiousness group, whereas verbal encouragement led to a non-significant decrease in MVC in the high-conscientiousness group. Percentage change in MVC across experimental conditions was significantly different between the groups, with a 9.72% increase during verbal encouragement of the low-conscientiousness group, and a 2.47% decrease during verbal encouragement of the high-conscientiousness group.

The peristimulus frequencygram (PSF) has recently been shown to illustrate postsynaptic potentials of motoneurones much more reliably than the peristimulus time histogram (PSTH). The aim of this investigation was to examine the profile of the postsynaptic potential (PSP) in soleus motoneurones in response to an H-reflex with and without accompanying M waves of different magnitude by using PSTH and PSF profiles of single motor units. Nine men and five women healthy subjects participated in this study. Electrical stimuli were delivered to the tibial nerve in the popliteal fossa. The reflex response of the soleus muscle was recorded using both surface electromyogram and single motor unit potentials. The PSTH analysis demonstrated that there were four different synaptic events following low-intensity stimulation of the tibial nerve: primary enhancement in firing probability (H-reflex or E1), primary reduction in firing probability (primary silent period or SP1), secondary reduction in firing probability (secondary silent period or SP2), and secondary enhancement in firing probability (E2). On the other hand, the PSF analysis indicated only two reflex responses, long-lasting enhancement in discharge rate including the H-reflex (LLE) and long-lasting decrease in discharge rate (LLD). The results of the two analyses methods are compared and contrasted. While the PSTH demonstrated that there was a silent period (SP1) immediately following the H-reflex, the PSF indicated an increase in discharge rate during the same period. The PSF also indicated that, during SP2 and E2, the discharge rate actually decreased (LLD). It was therefore suggested that LLD involved activation of several inhibitory pathways including the autogenic inhibition of units via the Golgi tendon organs. It was concluded that the PSF could indicate the details of the postsynaptic potentials and is very useful for bringing out previously unknown effects of electrical stimulation of muscle nerves.

We have induced H-reflex responses in human tibialis anterior motor units and analysed the results using the classical technique, peristimulus time histogram (PSTH), and a new technique, peristimulus frequencygram (PSF). The PSF has recently been shown to be more reliable than the PSTH for indicating the synaptic connections on motoneurones, and therefore we wished to examine the differences between the two analysis methods. Experiments were conducted on eleven healthy subjects (7 males and 4 females) who did not have any known neurological disorder. The subject sat comfortably on a dental chair and the common peroneal nerve was stimulated. In each experiment, about 600 electrical stimuli were applied to the nerve randomly between 1 and 2 s. The recordings were taken with both by surface electromyogram (SEMG) and as single motor unit potentials. We found that, when a stimulus induces an H-reflex, it also generates a period of reduced activity (silent period) and a long latency excitation in the PSTH. However, the PSF records in general do not match the indications of the PSTH records. For example, when the PSTH indicated existence of a silent period immediately following the H-reflex response, the discharge rate of the unit was in fact higher than the prestimulus rate. On the contrary, during the PSTH illustrated long latency excitatory response, the discharge rate was lower than the prestimulus rate. Our findings suggest that PSF gives significantly different results compared with the PSTH in determining the synaptic connection of the low threshold muscle afferents to the motoneurones. While PSTH indicated that there was a silent period immediately after the H-reflex, the PSF demonstrated that the silent period was actually a continuation of the net excitatory effect and not a genuine inhibition since the small number of action potentials occured during this period displayed higher discharge rates than the prestimulus level. Furthermore, the long latency excitation, as it was indicated in the PSTH; was actually a net inhibitory effect since the large number of spikes that occured during that period had lower discharge rates than the prestimulus average. In the lights of the recent brain slice findings and completely different results obtained using the two analysis techniques, we suggest that the PSF analysis should be used along with the PSTH to illustrate the net synaptic connection between peripheral receptors and motoneurones in the human nervous system.

Double discharges (doublets) were recorded from human soleus (SOL), where they have never been reported before. The data analyzed in this study were collected from 12 healthy volunteers. The subjects were recruited for other studies, concerning: (1) estimation of motoneurons’ (MNs) afterhyperpolarization (AHP) duration and (2) analysis of motor unit responses to nerve stimulation, and were not trained to voluntarily evoke doublets. The majority of intradoublet intervals fell into the commonly accepted range 2–20 ms. However, two SOL MNs from one presented exceptional doublets of intradoublet interval about 37 ms. This interval was virtually identical with the interval between second and third discharge in the few triplets recorded from another subject. It is hypothesized that triplets are generated by the delayed depolarization with the second narrow hump, which is the same as the hump responsible for exceptional doublets.

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