The Impact of Acute Stress Physiology on Skilled Motor Performance: Implications for Policing

Abstract

Investigations of police performance during acutely stressful situations have primarily focused on higher-order cognitive processes like attention, affect or emotion and decision-making, and the behavioral outcomes of these processes, such as errors in lethal force. However, behavioral outcomes in policing must be understood as a combination of both higher-order processes and the physical execution of motor skills. What is missing from extant police literature is an understanding of how physiological responses to acute stress contribute to observed decrements in skilled motor performance at the neuromuscular level. The purpose of the current paper is to fill this knowledge gap in the following ways: (1) review scientific evidence for the physiological (i.e., autonomic, endocrine, and musculoskeletal) responses to acutely stressful exposures and their influence on skilled motor performance in both human and animal models, (2) review applied evidence on occupationally relevant stress physiology and observed motor decrements in performance among police, and (3) discuss the implications of stress physiology for police training and identify future directions for applied researchers. Evidence is compelling that skill decay is inevitable under high levels of acute stress; however, robust evidence-informed training practices can help mitigate this decay and contribute to officer safety.

Biochemical response to sport related anxiety

“…if a person is anticipating an unfavorable outcome of a situation. However, both emotions activate the sympathetic part of the autonomic nervous system 17 . Even though their perception and stimuli might differ, the physiological response to them is the same.…”

“…Even though their perception and stimuli might differ, the physiological response to them is the same. They trigger a complex stress response: activation of the amygdala, the hypothalamic pituitary adrenal axis (HPA), and influence other endocrine and physiological factors such as respiration, cardiovascular functions or blood glucose levels, all effectors of the fight and flight response 16,17 . If the brain senses stress, the amygdala is activated as part of the sympathetic stimulation.…”

“…Cortico-releasing hormones (CRH) are secreted by the hypothalamus and, in turn, trigger the adrenocorticotropic hormone (ACTH) secretion from the anterior pituitary gland. ACTH is a major hormone in the stress response because it activates the adrenal cortex and results in the release of glucocorticoids (GCs), like cortisol 17 . Additionally, sympathetic stimulation also causes the adrenal medulla to release catecholamines.…”

“…One factor that decreases performance is an increased muscle tension related to high stress levels. Lundberg et al 17 state that stress activates low threshold motor units and increases the muscle tension even without any workload. Over time, an increased muscle tonus could cause nutrient depletion and the accumulation of waste and inflammatory substances, which then lead to stiffness 20 .…”

“…There does not seem to be one universally accepted mechanism for stress-induced muscle tension 22 , but an increased tension in the resting state certainly interferes with the fluidity of motor unit recruitment and results in decreased motor skills. Furthermore, the stress response causes stronger and more energetic movements due to sympathetic activation, which comes at a cost of precision 17 . Additionally, fine motor skills seem to be interrupted by the stress hormone cortisol.…”