It’s Probably Not What You Think.
It’s a measure of your [unshakable] belief in being able to reach your true potential, despite obstacles and barriers. High levels of Mental Toughness means that despite everyday challenges, personal goals such as sales, race time, GPA or other goals and pursuits can be improved. As you might expect, higher performing triathletes exhibit a higher MT.
A National Institutes of Health study of endurance athletes, triathlon, swimming, biking, using several psychological profile tests, created three categories of Mental Toughness (MT): Low, Medium and High.
Furthermore, a quick Google search reveals a growing number of training courses that are available to improve Mental Toughness; the courses are mostly psychological in nature, involving visualization, self- examination, and problem solving. One of the many organizations, Mentaltraininginc, calls the characteristics the ‘four pillars of mental toughness”: Motivation, Coping with Pressure, Concentration, and Self Belief.
My personal MT is really pretty good (most of the time) according to an online test I took, from one of the online training courses, as an introduction to their program. I found that my experience as a triathlete, an actor, an engineer having to meet deadlines, and just surviving growing up in the North Country in the cold, are/were pretty good teachers for developing mental toughness.
There are some surprising observations, too. For instance, someone with low Mental Toughness sometimes will try to overcome an impossible situation, to compensate for a lack of self-esteem. In the end, failing, rather than coping with the situation, like one who has a more healthy view of their capabilities. The research article is interesting, quite scientific, but worth a look: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5825049/