Differential expression of lymphocyte markers by neighborhood opportunity among US adults: Insights from the Midlife in the United States study.

Research on the determinants of physical performance has traditionally proceeded along two parallel tracks. Exercise and sport science has focused on physical predictors such as body composition, cardiorespiratory fitness, and training history [, ], while sport and exercise psychology has examined the role of psychological factors including anxiety, self-efficacy, and mental toughness [, ]. In practice, however, physical and psychological factors do not operate in isolation [, ]. Body composition may shape psychological states. For example, a student with elevated body mass index (BMI) may experience heightened anxiety in a context that publicly evaluates physical capacity, and psychological states in turn modulate how effectively physical capacities are deployed under pressure. Despite the longstanding recognition of this bidirectional interplay within biopsychosocial frameworks [, ], surprisingly few empirical studies have examined the indirect associations through which physical factors relate to performance via psychological factors. This gap is compounded by a sampling limitation: most research on psychological predictors of physical performance has been conducted with competitive athletes, whose physical capacities cluster within a narrow range and whose psychological resilience is subject to self-selection, restricting the variance in both domains that is needed to detect indirect associations []. Among the psychological factors most consistently linked to physical performance, anxiety and mental toughness occupy central roles. We focus on these two constructs because they represent the two theoretically opposing psychological processes most directly implicated in evaluative physical performance: a debilitative process and a facilitative resource. Multidimensional anxiety theory [] distinguishes between cognitive anxiety and somatic anxiety. Cognitive anxiety involves worry, self-doubt, and negative performance expectations; somatic anxiety involves physiological activation such as elevated heart rate and muscle tension. Both have been associated with impaired sport performance through attentional disruption and effort dysregulation. Mental toughness refers to the psychological capacity to perform consistently under varying conditions of stress and adversity []. It has been positively associated with sport performance across diverse contexts [], with its protective function theorized to operate through superior self-regulation and persistence under discomfort. We model anxiety and mental toughness as parallel rather than sequential linking variables, because they are conceptually distinct processes theorized to operate concurrently rather than one through the other, with anxiety serving as the debilitative process and mental toughness as the facilitative resource. Other psychological constructs such as self-efficacy, motivational regulation, and perceived competence are also relevant, and we return to them in the Discussion; the present study was designed around this debilitative–facilitative pairing rather than as a comprehensive psychological model. Three further considerations constrain the current evidence. First, anxiety and mental toughness are typically modeled as direct predictors rather than as variables through which upstream physical factors may be indirectly associated with performance. Second, few studies have examined non-athlete populations in compulsory evaluation contexts. Third, although gender differences in anxiety and body composition are well documented, the possibility that the indirect role of psychological factors depends on the physical demands of the specific performance task has received little attention. This third point warrants emphasis. In many standardized physical assessments, males and females complete different test items that impose different biomechanical demands [, ]. If a male-specific item (e.g., pull-ups) creates a stronger physical constraint from body mass than a female-specific item (e.g., sit-ups), then the relative contribution of psychological factors to performance may differ not because of gender per se, but because the task ecology differs []. An observed “gender difference” in biopsychosocial association patterns could therefore reflect, at least in part, a task-structure-dependent difference [, ]. We emphasize, however, that gender and task structure are inseparable in any system that assigns test items by gender: because the same individuals who share a gender also share a test battery, the two cannot be experimentally or statistically disentangled. The most that such a context can offer is a comparison of association patterns across gender-differentiated testing contexts, with the source of any difference remaining open; this difference may reflect task structure, biological sex, or their interaction.