Use your Gi Top hung through a ring or over a racked barbell so that the sleeves are hanging. Set a timer clock to beep every 10 seconds.
Hang from the top of the sleeves near the armpit. Every 10 seconds, do a row, and come back to hanging position. Hang on as long as you are able.
Most of the Lab Rats finished in 10-11 Rounds, or 1:40-1:50min total time.
If you are conducting the intervals, use your assessment time and the prescribed percentage to determine how long to hang for each round.
30% Gi Grip Strength Assessment
Rest 45 Seconds between Rounds
If my assessment was 1:40, break it down in to seconds. 1:40 = 100 seconds.
100 seconds x .30 = 30 seconds
One round will be a 30 second hang from the gi, with a row every 10 seconds. Rest for 45 seconds, and repeat.