Here is my current cardio routine
I use a 32 kg kb for my heavy swings and a 16kg kb for my single arms
Timer or Gymboss set at 15 sec of work, 15 sec of rest.
Jump Rope
Heavy Swing
Jump Rope
1 Arm Swing (Right)
Jump Rope
1 Arm Swing (Left)
Take 30-45 seconds of rest and repeat for a total of 5-6 rounds
I do this 3 days weekly and 2 days I ride a treadmill uphill for about 40 minutes