At a recent soccer coaching education course, a guest lecturer, who also worked as a college soccer coach, flew in to give a talk titled “Psychology.” The all-encompassing title intrigued me, and inspired the hope that maybe this 60-minute lecture could sufficiently inform me about the subject, potentially saving me several hundreds of thousands of dollars in NYU tuition. Alas, I was disappointed. The hour was spent by rattling off extremely abstract explanations of profoundly mundane concepts, including the ever-popular “mental toughness,” as well as mentioning in passing the ubiquitous (but not unimportant) “Zone,” or “Flow,” demonstrating a very elementary knowledge of the concept. Sports psychology is often explained by non-professional sports psychologists in two or three minutes as comprising these two components (mental toughness and The Zone), but there are countless ideas in the field of psychology that can contribute to the development of athletic excellence not only as direct interventions for athletes, but also as concepts that inform the methodologies by which young athletes are coached. Of the many concepts in psychology that apply to sports development and performance, the usefulness of stress is an exceptionally interesting and often overlooked one. In this paper, I will discuss two theories (both of which have been supported by empirical research) of the usefulness of stress that may be applicable to athletic development and performance .
First, it is important to distinguish between the terms “development” and “performance.” To develop something is to cause it to grow in size and complexity, while performance is “the execution of an action” (“Performance,” n.d.). In youth sports, performance is often far overvalued, while development is undervalued; this is highly illogical, as the goal of elite youth sports is to develop elite athletes. Clearly development should be the priority, but performance is not irrelevant to the process; it can be used as a tool for progress assessment, and high performance can have a positive effect on confidence and engagement, which in turn are massively beneficial for development in all areas (Compte & Postlewaite, 2004).
Both theories of stress exposure are inspired by the Yerkes-Dodson Law, which states that optimal performance in difficult tasks is achieved under medium “arousal,” or stress (see fig. A).
FIGURE A
Chaby et al.
In their articles, “Can We Understand How Developmental Stress Enhances Performance Under Future Threat With the Yerkes-Dodson Law?” and “Does Early Stress Prepare Individuals for a Stressful Future?” Lauren E. Chaby, Michael J. Sheriff, Amy M. Hirrlinger, and Victoria A. Braithwaite write about the efficacy of developmental stress in enhancing future performance. In their first article (“Does Early Stress Prepare Individuals for a Stressful Future?”), the authors ask whether exposing rats to high-stress environments in their adolescence will enhance their foraging performance under similar high-stress circumstances in their adulthood. The experimenters took an admirable amount of care in operationalizing their variables accurately, designing valid and ethical methods, and eliminating confounds and experimenter bias to the extent that that is possible.
The rats in the experimental group were exposed to physical, social, and predatory stressors during adolescence, while the rats in the control group were not. The experimental group was exposed to stress regularly for their entire period of adolescence (and the commonly accepted period of development of the prefrontal cortex, “a region which continues to develop into early adulthood”) (Chaby, Sheriff, Hirrlinger, & Braithwaite, 2015a). After a delay of five weeks, the now adult rats were tested for changes in their body mass, their motivation to consume a reward, their foraging behavior, and their foraging performance in an artificial foraging environment under both high- and low-threat circumstances.
The researchers found, among other, minor findings, that “chronic stress exposure during adolescence and early adulthood had long-term effects on foraging under low- and high-threat conditions” (Chaby et al. 2015a, p.41). In low-threat environments, adolescent stress exposure affected foraging behavior but not foraging performance, and across two low-threat tests, the control and experimental groups improved in performance at the same rate, “suggesting that stress during adolescence does not affect the ability to learn a foraging task” (41). However, in the high-threat environment, rats in the experimental group consumed 43% more rewards than those in the control group, suggesting that adolescent stress exposure “enhanced foraging-related problem solving under threat and…[suggests] that prior stress prepares…animals to function better under future threat” (41). These results, which support the authors’ original hypothesis, suggest that the concept may be applicable to human athletic development.
In a follow-up review published later that year, the authors of the original study sought to reexamine their results explicitly through the framework of the Yerkes-Dodson Law. The law, the authors write, “describes a context-specific relationship between performance and arousal that we have modeled using high and low-threat conditions” (Chaby et al. 2015b, p.1). In reference to the curvilinear nature of the graph, the authors note that while adolescent stress exposure did not increase the optimal level of performance of the original graph, it did allow for a comparable optimal level of performance to be achieved in a higher-arousal (or higher-threat) environment (see fig. B). This creates an entire area of the graph that delineates “conditions where early stress provides a performance advantage” (1).
FIGURE B
The conclusions drawn in these studies, which suggest that exposure to stress in the adolescent period of development can improve future performance under high stress without impairing future performance under low stress, can be applied very cautiously to elite sports development. The suggestion is that to improve performance on a high stage (i.e. an extremely high-stress performance environment), young athletes must be exposed to controlled levels of physical and social stress (presumably with stressors similar to those they would encounter during performance) during development. This means training conditions must be adjusted to include an increased level of physical or social difficulty or discomfort. However, these results are also consistent with the theory that adolescent stress exposure can lead to permanent behavioral changes, including an increase in avoidant behavior even in low-threat situations, which could be good or bad. Avoidant behavior (especially risk-avoidant behavior) can be very detrimental to a young athlete’s development; it is crucial that more research be done in an effort to avoid the pitfalls that turn healthily cautious, efficient behavior into avoidant behavior.
Rietschel et al.
In their article, “Cerebral Cortical Dynamics and the Quality of Motor Behavior During Social Evaluative Challenge,” Jeremy C. Rietschel, Ronald N. Goodman, Bradley R. King, Li-Chuan Lo, Jose L. Contreras-Vidal, and Bradley D. Hatfield use the same underlying concept (Yerkes-Dodson) to investigate whether cerebral cortical dynamics (and by proxy, cognitive-motor performance) were affected by the level of arousal, or stress, present during the time of the performance. Subjects were required to complete a set of difficult aiming tasks both alone and “in a social evaluation condition” (Rietschel et al., 2011, p.482). Heart rate, skin conductance, and self-reported mood were measured to ensure that subjects felt a moderate sense of arousal during the social evaluation conditions. Electroencephalogram (EEG) channels were used to measure electrical brain activity during the tasks.
The researchers found that in environments of moderate arousal, the EEG readings showed changes in cerebral cortical dynamics, which allowed for “superior…motor performance” (Rietschel et al. 2011, p.479). This supports their initial hypothesis, and is consistent with the Yerkes-Dodson Law. These results suggest that the implementation of a social evaluative presence during performance might improve motor and cognitive behavior. Athletic coaches and trainers at all levels should take note of the positive influence of moderate evaluative stress on performance, and should consider how best to implement such an influence while taking extreme care not to negatively affect the athlete’s confidence.
Conclusion
The authors of these three studies on the use of stress, all of which have their roots in the Yerkes-Dodson Law, strongly suggest that their findings may be applicable to humans in many areas of performance, including motor and physical performance (Rietschel et al.) as well as survival and cognitive performance (Chaby et al.). The findings of both studies suggest that strategic implementation of different types of developmental and evaluative, performance-associated stress can be both psychologically and physiologically useful in preparing young athletes for the emotional demands of elite athletic performance. In all sports, performance often happens in high-threat or high-stress environments, coming from the opposition, observers, evaluators, or all of the above; a simple way to safely add realistic stress to the training environment would be to make training more like “the game” (which is something coaches already often try to do), but it may also be possible to further increase the level of stress in a healthy way or to introduce this stress without sacrificing the isolated nature of many training exercises. Coaches of elite athletes at all points on the developmental timeline should take note of these findings and should begin to customize a long-term program of stress exposure that fits with the athlete’s biological age, physiological and psychological conditions, and the sport in question, taking care to avoid over-stressing the athlete (thus hopefully avoiding the negative physiological effects of overexposure at a young age).
However, a massive amount of further study is needed before it is possible to create a scientifically sound stress exposure program for adolescent humans; human development and learning experts should consult with professional coaches and trainers to develop the scope and sequence of the program, as well as the types of constraints and stressors prescribed. Separately, more study is needed on how to incorporate a stress program into a training environment which is meant to encourage risk-taking and confidence, and on the prevention of the negative effects of overexposure to stress.