28 Sep CrossFit WOD, September 29, 2018
A black jack is a simultaneous ascending and descending ladder of 2 movements. The total of the 2 movements reps will always equal 21. So you will do 20 Burpees and 1 KB Swing. Then 19 Burpees and 2 KB Swings. So on and so forth.
There is a 20 minute cap on this workout.