Its described in the preprocess section of the caret manual (about half way down page): http://caret.r-forge.r-project.org/preprocess.html
so for you cadets data it's something like (not tested):
cadetsCor <- cor(cadets)
highlyCorCadets <- findCorrelation(cadetsCor, cutoff = 0.75)
cadets <- cadets[, -highlyCorCadets]
The other alternative is dimension reduction.. e.g PCA but then your model maybe gain in predictive power but lose interpretability.