Browsing by Subject "Mediation analysis"

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    Open Access
    Modelling perception-action coupling in the phenomenological experience of “hitting the wall” during long-distance running with exercise induced muscle damage in highly trained runners
    (Springer International Publishing, 2018-07-10) Venhorst, Andreas; Micklewright, Dominic P; Noakes, Timothy D
    Background “Hitting the wall” (HTW) can be understood as a psychophysiological stress process characterised by (A) discrete and poignant onset, (B) dynamic interplay between physiological, affective, motivational, cognitive, and behavioural systems, and (C) unintended alteration of pace and performance. A preceding companion article investigated the psychophysiological responses to 20-km self-paced treadmill time trials after producing exercise-induced muscle damage (EIMD) via a standardised muscle-lengthening contraction protocol. Methods A 5-step procedure was applied determining the extent to which the observed data fit the hypothesised cause-effect relationships. Running with EIMD negatively impacts performance fatigability via (A) amplified physiological responses and a non-adaptive distress response and (B) deterioration in perceived fatigability: increase in perceived physical strain precedes decrease in valence, which in turn precedes increase in action crisis, eventually dissolving the initially aspired performance goal. Results First, haematological indicators of EIMD predicted increased blood cortisol concentration, which in turn predicted increased performance fatigability. Second, perceived physical strain explained 44% of the relationship between haematological indicators of EIMD and valence, which in turn predicted increased action crisis, which in turn predicted increased performance fatigability. The observed data fitted the hypothesised dual-pathway model well with good model-fit indices throughout. Conclusions The hypothesised interrelationships between physiological strain, perception, and heuristic and deliberative decision-making processes in self-regulated and goal-directed exercise behaviour were applied, tested, and confirmed: amplified physiological strain and non-adaptive distress response as well as strain-perception-thinking-action coupling impact performance fatigability. The findings provide novel insights into the psychophysiological processes that underpin the phenomenological experience of HTW and alteration in pacing behaviour and performance.
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    Open Access
    Symptoms of posttraumatic stress partially mediate the relationship between gender-based violence and alcohol misuse among South African women
    (BioMed Central, 2023-06-22) Nguyen, Kim A.; Myers, Bronwyn; Abrahams, Naeemah; Jewkes, Rachel; Mhlongo, Shibe; Seedat, Soraya; Lombard, Carl; Garcia-Moreno, Claudia; Chirwa, Esnat; Kengne, Andre P.; Peer, Nasheeta
    Abstract Background The association of traumatic experiences with problematic alcohol use has been described, but data on possible mediation effects of mental distress are sparse. We examined whether mental ill-health mediated the association between trauma exposure across the lifespan and alcohol use. Method We analysed cross-sectional data from a sample of rape-exposed and non-rape-exposed women, living in KwaZulu-Natal, with self-reported data on alcohol misuse (AUDIT-C cut-off ≥ 3) and exposure to childhood maltreatment (CM), intimate partner violence (IPV), non-partner sexual violence (NPSV), other traumatic events, and mental ill-health. Logistic regression and multiple mediation models were used to test the mediation effects of symptoms of depression and PTSS on the association between abuse/trauma and alcohol misuse. Results Of 1615 women, 31% (n = 498) reported alcohol misuse. Exposure to any CM (adjusted odds ratio (aOR): 1.59, 95% confidence interval (CI): 1.27–1.99), as well as to sexual, physical and emotional CM, were independently associated with alcohol misuse. Lifetime exposure to any IPV (aOR:2.01, 95%CI:1.59–2.54), as well as to physical, emotional and economic IPV, NPSV (aOR: 1.75, 95%CI: 1.32–2.33), and other trauma (aOR:2.08, 95%CI:1.62–2.66), was associated with alcohol misuse. Exposure to an increasing number of abuse types, and other traumatic events, was independently associated with alcohol misuse. PTSS partially mediated the associations of CM, IPV, NPSV and other trauma exposures with alcohol misuse (ps ≤ 0.04 for indirect effects), but depression symptoms did not. Conclusions These findings highlight the need for trauma-informed interventions to address alcohol misuse that are tailored to the needs of women who have experienced violence.