Subjects were untrained men, 20 to 35 years of age. Training
intensity was between 85 to 90 percent of maximum heart rate.
Percentages have been rounded.
When running more than 3 days per week, or more than 30 minutes
per session, additional improvements in cardiovascular fitness
are small, yet the rate of orthopedic injuries are disproportionately
greater. Although slightly higher increases of cardiovascular
fitness were observed for the 45 minutes per session and 5 days
per week groups, these programs are not recommended for beginning
joggers due to significantly higher rates of injury.