This study investigated the somatosensory and corticomotor physiology of retired contact sport athletes with a history of repeated concussion/subconcussion head trauma.
Retired male athletes with a ...history of playing contact sports and repeated head trauma (
= 122) were divided into two groups: those who expressed concerns regarding their mental and cognitive health ("symptomatic":
= 83), and those who did not express any ongoing concerns ("asymptomatic":
= 39). Both groups were compared to age-matched male controls (
= 50) with no history of concussions or participation in contact sports, an absence of self-reported cognitive, or mood impairments. Transcranial magnetic stimulation (TMS) and vibrotactile stimulation were used to assess corticomotor and somatosensory pathways respectively. TMS and vibrotactile stimulation were correlated to self-reported responses using the Fatigue and Related Symptom Survey. Linear regression was used to associate concussion history with TMS, somatosensory variables.
Significant differences were found in symptom survey scores between all groups (
< 0.001). TMS showed significant differences between the "symptomatic" and control groups for intracortical inhibition and paired pulse TMS measures. Somatosensory measures showed significant differences for reaction time (
< 0.01) and reaction time variability (
< 0.01) between the "symptomatic" group to the "asymptomatic" and control groups. For other somatosensory measures, the "symptomatic" measures showed differences to the "control" group. Correlations showed significant associations between severity of symptom reporting with TMS and somatosensory measure, and regression revealed the number of concussions reported was shown to have significant relationships to increased intracortical inhibition and poorer somatosensory performance.
This study shows that retired contact sport athletes expressing chronic symptoms showed significant pathophysiology compared to those with no ongoing concerns and non-concussed controls. Further, there is a linear dose-response relationship between number of reported concussions and abnormal neurophysiology. Neurophysiological assessments such as TMS and somatosensory measures represent useful and objective biomarkers to assess cortical impairments and progression of neuropsychological impairment in individuals with a history of repeated head trauma.
Cortisol is a steroid hormone that follows a distinct diurnal timeline; however, while healthy ranges exist, it not been determined whether or why individuals differ on baseline cortisol levels. The ...aim of this study was to test the anecdotal evidence of different levels of responders by classifying these levels in resting cortisol, and to correlate individual cortisol responses to psychological traits.
Twenty-two male athletes (mean age 22.5 ± 4.34 years) provided two saliva samples at the same time each day over three days in week one of their pre-season to determine individual baseline salivary cortisol levels. Participants also completed self-report psychological traits measures for correlation to cortisol levels.
Three levels of cortisol in responders were clearly identified (
= 69.00,
< 0.001). Pearson's correlation coefficient showed that there was no significant relationship between baseline cortisol levels and psychological traits (optimism,
= 0.23,
= 0.29; stress,
= 0.05
= 0.82; decision making,
= 0.19
= 0.38).
This novel study identified that within an overall healthy range, individual athletes will likely fall into either a low, average or high band of baseline cortisol. However individual responses did not correlate to self-report psychological traits. Caution is required if sports science staff wish to use cortisol to measure psychological stress.
International concern continues regarding the association between the long-term neurophysiologic changes from repetitive neurotrauma associated with contact and collision sports. This study describes ...corticomotor changes in retired contact/collision sport athletes and controls, between the ages of 30 and 70 years. Retired athletes (n = 152; 49.1 ± 8.5 years) and controls (n = 72; 47.8 ± 9.5 years) were assessed using single and paired-pulse transcranial magnetic stimulation (TMS) for active motor threshold (aMT), motor evoked potential and cortical silent period duration (expressed as MEP:cSP ratio), and short- and long-interval intracortical inhibition (SICI and LICI). Motor threshold, MEP:cSP, SICI and LICI for both groups were correlated across age. Controls showed significant moderate correlations for MEP:cSP ratios at 130% (rho = 0.48, p < 0.001), 150% (rho = 0.49, p < 0.001) and 170% aMT (rho = 0.42; p < 0.001) and significant small negative correlation for SICI (rho = −0.27; p = 0.030), and moderate negative correlation for LICI (rho = −0.43; p < 0.001). Group-wise correlation analysis comparisons showed significant correlation differences between groups for 130% (p = 0.016) and 150% aMT (p = 0.009), specifically showing retired athletes were displaying increased corticomotor inhibition. While previous studies have focussed studies on older athletes (>50 years), this study is the first to characterize corticomotor differences between retired athletes and controls across the lifespan. These results, demonstrating pathophysiological differences in retired athletes across the lifespan, provide a foundation to utilise evoked potentials as a prodromal marker in supplementing neurological assessment for traumatic encephalopathy syndrome associated with contact/collision sport athletes that is currently lacking physiological biomarkers.
•Repetitive head trauma has been shown to increase risk of neurodegenerative disease.•Corticomotor connections were assed in 152 athletes and 72 controls.•Athletes with head trauma showed reduced inhibitory response compared to controls.•TMS represents an approach exploring pathophysiology of repetitive head trauma.
Background: Concussion is regarded as a common injury in rugby league, however no studies have explored the long-term neurophysiological and cognitive effects of repeated concussion injuries in this ...sport.
Methods: Former professional rugby athletes (n = 25) were compared to 25 age-matched participants with no history of a concussion. All participants completed standardised motor dexterity, reaction time, and cognitive tasks for working memory, associative learning and rule acquisition and reversal. Single-pulse transcranial magnetic stimulation (TMS) acquired motor evoked potentials and cortical silent period (cSP), as well as paired-pulse TMS for short latency intracortical inhibition and long intracortical inhibition (LICI).
Results: Compared to controls, dexterity and visuomotor reaction time was slower in the rugby group compared to controls (p = 0.02, p < 0.01, respectively). The rugby group also demonstrated poorer cognitive performance than controls (p range 0.02 to < 0.01). TMS revealed significantly reduced cSP at suprathreshold stimulation intensities (p range 0.02 to <0.01), and increased LICI (p = 0.03) in the rugby group.
Discussion: These findings of motor and cognitive changes, along with neurophysiological alterations, particularly with intracortical inhibition, nearly two decades post-concussion provides evidence for long-term sequelae for athletes with a history of repeated head trauma in contact sports.
This study explored professional male Australian rules football players leaving the Australian Football League (AFL), either from retirement or from deselected from their team. Identified athletes (
...= 425) transitioning from the AFL competition from years 2019 to 2021 were invited to participate in an anonymous online survey with 60% completing the survey. Using scaled-response questions, responses were compared between groups across a number of areas including their experience of leaving, athlete identity, the influence of sport in their daily life, psychological flourishing, financial confidence, social relationships, and future career preparations. Results showed deselected players (
= 152), compared to retired players (
= 56), reported shorter career spans, and poorer perception of their club's handling of the transition process (
< 0.001). Compared to retired players, deselected players reported stronger identity attachment to sport, less confidence in their financial capabilities, and career outside football (all
< 0.05). Conversely retired players, compared to deselected players, showed stronger psychological flourishing. Correlations showed that retired players were more confidence in their finances, reported greater psychological flourishing, and lower attachment to an athletic identity (all
≤ 0.05). The results of this study suggest that as deselected players expressed poorer perception of club's handling of the transition process the role of AFL club staff could improve the transition process in in preparation for life outside of professional sport.
The purpose of this study was to examine Australian Football athletes’ responses to a grade one muscular injury from a psychophysiological perspective to understand the strength of the association ...between stress, optimism, and cortisol. Forty-five players listed with one professional Australian Football club volunteered for this study. Inclusion criteria consisted of sustaining a muscular injury during the course of the season with four-weeks predicted recovery time (as diagnosed by club medical staff, n=9). The control group were age, position, and career history matched players from the same sample. Players were also matched for their personality (10-item Big Five Personality Inventory) and fluid intelligence (Raven’s Standard Progressive Matrices). Injured players and matched controls completed perceived stress and optimism measures (paper-based questions) as well as salivary cortisol testing once per week for four weeks. Significant increases in cortisol (
p
=0.015) and perceived stress (
p
<0.001) were observed in injured players, along with a reduction in optimism (
p
<0.001) returning by week 4. A significant positive correlation was found between perceived stress and cortisol (
r
= 0.426), and significant negative correlations observed between optimism and cortisol
r
= −0.257 and perceived stress
r
= −0.391. This study showed that athletes were significantly stressed and less optimistic during the first two-weeks of recovery compared to matched controls. While not statistically significant, large effects observed in cortisol and stress in the week prior to returning to competition in the injured group suggest these results demonstrate that a multi-modality approach can improve understanding of psychophysiological stress following a grade one muscular injury in Australian Football athletes.
Concussion in sport is a growing public health issue. However, research suggests that under-reporting of concussion by student-athlete cohorts reflects conflicting attitudes compared to the wider ...community. Interestingly, previous studies have focused on the attitudes and beliefs irrespective of the type or level of sport played at. This study explored concussion beliefs and attitudes in a cohort of Australian exercise science students, analyzing responses based upon the type and the level of sport participated. Two-hundred and ninety-four students (m = 208; f = 86; age 22 ± 5.2 years) responded to a series of statements regarding their personal attitudes and beliefs towards concussion, risk playing with a concussion, and their views on elite/professional athletes who continue to play after a concussion. Data was compared between the type of sport played (team and individual, contact and non-contact) and the level of sport played at (elite, regional and recreational). Significant differences were reported in those experiencing a concussion, and the number of concussions sustained between different types of sports. Specifically, significant differences in attitudes between team-contact versus individual non-contact sports were found. Similarly, significant differences in attitudes were observed between team contact and individual non-contact sports. Conversely, similar attitudes were found between team contact, team non-contact and individual contact. Irrespective of the level of competition, no differences were found in previous concussion history and the number of concussions, reflecting similar attitudes. The data from this study suggests that concussion awareness programs should be delivered across all sports and to all levels.
Elite competitive sport is linked with a unique collection of stressors distinct from the general population. While there have been advancements in understanding the role that stressors play within ...the elite sporting environment, uncertainty still exists around a clear process for measuring stressors, and their specific relationship to injury. A number of models have been proposed as useful frameworks for investigating and describing the role of stress and its interaction with the psychological response to athletic injury. While these models provide evolving points of view drawing on different theoretical backgrounds regarding their interpretation of athletic stress and injury, they offer little application to the applied elite sporting environment, and no detail of how they these models support athletes, and high performance staff in the applied setting. This narrative review will present two popular theoretical psychological models of sports injury rehabilitation. We argue that these models could be better applied in the current sporting environment if they utilized biological markers such as cortisol measures of personality. Extending from the Biopsychosocial model of injury, we present an updated model of injury quantifying the psychophysiological response for athletes 1. This model is aligned with the current applied sporting landscape, incorporating the implementation of measurement practice guidelines, and offering high-performance staff an example that can be applied to their unique setting by assessing individuals' distinct measures of cortisol and personality in response to stress and injury.
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