21-15-9 Descending Rep Workout for Time

A for-time workout with two bodyweight exercises in sets of 21, 15, and 9 reps; each student chooses the version of the exercise they can do with good form. It builds muscular endurance and teaches pacing under fatigue.

How to play

1. Write the challenge on the whiteboard: jump squats and push-ups, 21-15-9 (21 of each, then 15 of each, then 9). Show three levels of each exercise (3 min).
2. Pairs: each student picks a level and predicts their time before starting.
3. Round one (6 min): one partner works while the other counts reps and records the finish time the teacher calls out every 10 seconds.
4. Round two (6 min): switch roles with the same format.
5. Compare (5 min): students compare their actual time with their prediction and note which set slowed them down most.

Rules

• If form breaks down, drop a level without stopping the clock.
• Everyone works on their own mat, at least 3 feet apart.
• Only full reps count: the partner counts them out loud.

Variations

Adaptations

• Limited mobility: band presses and seated crunches using the same scheme.
• Autism: the partner holds up a sign with the current set so the count is easy to follow.
• Lower fitness level: break each set into small chunks with rest as needed.

Learning goals

• Improve muscular endurance with a descending rep format.
• Choose the right difficulty level and maintain form under fatigue.
• Compare self-perception with actual performance.

Equipment for a class of 25

• yoga mats: 25
• stopwatch: 1
• whiteboard: 1

Teacher tip

Push the time prediction: it teaches students to know themselves. The usual mistake is sprinting the first 21; remind them it is better to break up sets from the start.

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