HIIT produces increases in muscle power and free testosterone in male masters athletes The High-Intensity Interval Training (HIIT) is now an established method for top athletes. An English group has now examined the influence of a 6-week HIIT on the performance of male age-class athletes at a mean age of 60 years.
It showed that this training form not only significantly increased the performance, but still increases the free testosterone. This interesting article can be found under https://pubmed.ncbi.nlm.nih.gov/28794164/