Stress, an Injury Risk Factor for Runners

Introduction

There’s no question running is one of the most popular, most covered, and most unifying athletic activities of the 21st century. No wonder: it allows those who practice it to keep in shape, get out and about, and spend quality time with friends. In France alone there are nearly 10 million runners, and 60 million in the U.S.!

The downside is that both regular and occasional runners can sometimes become the victims of injury. Poor form (Kluitenber et al., 2016) or a history of injuries (Saragiotto et al., 2014) are known to be the biggest factors in this regard. The scientific research also shows that feeling fatigued before starting, compounded with the daily stresses of life, can increase the likelihood of injury (Junge, 2000)..

What is stress? And why does stress have a negative impact in terms of injury?

Stress: a useful reaction in the short-term

According to the Greek philosophers, health is defined through the concepts of balance, stability, and harmony.

For the World Health Organization, health is defined as “a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity”

(WHO, 1946)

Being in good health is therefore living in balance.

Stress exists when the body is out of balance (Fig. 1). In 1946, Selye described three stages of stress manifesting.

• First: the body goes on alert due to some kind of external stimulus.
• Second: it reacts to the stimulus by calling on its own physical and psychological resources.
• Third: these resources help the body restore the balance.

When the body is in a state of stress, it calls on all of the physical and psychological resources it possesses. The psychological resources help to quickly analyze the situation. The physical resources help provide the physical strength needed to fight or flee (Fig. 1).

The body’s adaptive response is extremely quick. In scientific terms, the system for responding to stress is called the hypothalamic–pituitary–adrenal axis (HPA axis or HTPA axis). When a stressor is identified, a small area of the brain, called the hypothalamus, sends chemical messages to the pituitary gland. From there, a second chemical message is sent by the circulatory system to the adrenal glands in order to activate cortisol production. Once secreted, the cortisol acts to provide the brain with enough energy to prepare us to face the stress. This influences the regulation of arterial pressure, cardiovascular function, and immune system function. In addition to cortisol, the body simultaneously excretes adrenaline. This hormone’s role is to prepare the body to respond to stress by increasing heart rate, respiratory rate, and arterial pressure. The objective of this is to cause blood to flow very quickly throughout the entire body so that it has all the resources needed to either fight the threat or flee from it.

In the short term, extreme stress is beneficial as it lets us quickly call on available physical and psychological resources in order to react to an external stimulus that possibly threatens our survival.

And in the long term, what happens as a result of stress?

Stress: a negative reaction over the long-term

The type of stress that we most often hear about is chronic stress. Chronic stress appears when our body is constantly rebalancing itself. This happens when the stressful external stimulus has not disappeared. In the Selye (1946) model, this happens when the body’s resources aren’t adequate in helping it return to a state of equilibrium. In this case, the threat of the stimulus continues, and the body is in a state of constant rebalancing. This situation results in a state of physical and psychological exhaustion.

In our times, this type of stress often appears during a stressful situation relating to financial, emotional, or professional security. Being afraid of losing one’s job, of no longer being able to meet your basic needs, and not having any confidence in yourself are examples. If we compare these situations to those of our ancestors, it’s as if we’re scared of being attacked by a lion day and night over several days, which leaves us with the impression that we will never be able to escape the situation. This comparison is important because it helps us understand why we’re not made to handle stress in the long-term (Fig. 2).

Stress, running, and injuries

Being stressed daily causes physical and psychological exhaustion. However, practicing an athletic activity takes resources (physical and psychological; Carlier, 2017). That’s why, due to the considerable reduction in available resources, being stressed daily impacts the likelihood of injury (Fig. 3).

In order to run as prudently as possible, evaluate your level of stress on a scale from 1 to 10, with 1 meaning “not at all stressed” and 10 representing “maximum stress”. With your level of stress before running in mind, pay extra attention to your way of running during that session and to the pain you experience both during and after the run. This will help you understand if and how your daily stress impacts your likelihood of injury. With these insights, you’ll do a better job of keeping yourself injury-free so that your training can continue unhampered.

Written by:
Mauraine Carlier – Doctor of Psychology, specializing in Sports Neuropsychology and Psychology