James' hypothesis was that African Americans sometimes attempted to control their environment through similar attempts at superhuman performance. The expression of this superhuman performance may not necessarily involve a steel hammer. It may involve working harder at the office or working long to prove one’s worth. The end results, however, may still involve the same negative consequences that befell John Henry. James developed a 12 item scale called "The John Henryism Scale for Active Coping" or JHAC12 for measuring this strategy. Three themes that were deemed important in measuring John Henryism include:
The scale developed for measuring JH was based on agreement with a series of statements such as these:
"When things don't go the way I want them to, that just makes me work even harder"
"I've always felt that I could make of my life pretty much what I wanted to make of it."
In his seminal 1983 study, 132 southern, working classBlack men between the ages of 17 and 60 years were administered the John Henryism scale. The scale was used to measure the extent to which these men believed that they could control their environment through hard work and determination. In accordance with the author's hypothesis, subjects who scored low on educational variables and high on John Henryism had significantly higher levels of diastolic blood pressure than those who scored above the median on both measures. James believed that educational achievement and the John Henryism construct score may have a positive correlation with autonomic arousal in African Americans when these individuals have encounters with everyday stressors.
Effects
Men who scored higher on the John Henry scale were not found to have statistically significant differences in mean systolic blood pressure or mean diastolic blood pressure when compared to their lower scoring counterparts, however a significant effect did emerge in variation in percentage of hypertension. African American males who were categorized as low or medium SES and had high levels of John Henryism, had a significantly higher % of hypertension than their counterparts with low levels of John Henryism, however high SES individuals with high levels of John Henryism were found to have lower levels of hypertension than their low John Henryism, high SES counterparts. Studies have found that African-Americans with high scores are less likely to be current or former smokers than African-Americans with low JH scores. African-American college students with high JH scores were less likely to have carried a weapon on campus for self-defence, more likely to have been arrested for driving under the influence, and more likely to have missed a class due to alcohol use.