Dr Neil Meigh is a physiotherapist and associate professor at Bond University (Gold Coast Australia).   Neil conducted a pragmatic exercise intervention in insufficiently active older adults.  The intervention was a hard style kettlebell program in those aged 60-80.  These people were not life long athletes but many of them thrived in his program.  They got the type of results and improvements in fitness where an independent observer could be skeptical.     We talk details of the program and the resiliency seen in this population while performing high intensity exercise.   Neil's paper is here