Episode Details

Send us Fan Mail

Muscle endurance is the ability to repeatedly apply submaximal force, and it is directly tested in CrossFit in a variety of combinations and movement patterns.

Maximal strength appears to have significant predictive power over muscle endurance above 40% of 1RM.

This was demonstrated in a study that compared bench press 1RM to the results of a muscle endurance test.

Performance in the muscle endurance test depended on maximal strength, bodyweight and maximum absolute power.

The researchers concluded that the goal of a muscle endurance training program should be first to increase maximum strength until the specific load you are trying to endure is less than 40% of the individual’s 1RM.

Only then should training shift to improving muscular endurance in the specific task.

Six Examples

1. Repeated, Heavy Olympic Weightlifting

Athlete A
1RM Clean 335 lbs
315 lb Clean = 94% of 1RM

Athlete B
1RM Clean 400 lbs
315 lb Clean = 78% of 1RM

If the study results replicated, Athlete B would outperform Athlete A in this test.

2. Strict HSPU

Athlete A
Bodyweight = 195 lbs
Max Strict Press = 240 lbs
Strict HSPU = 81% of 1RM

Athlete B
Bodyweight = 195 lbs
Max Strict Press = 205 lbs
Strict HSPU = 95% of 1RM

If the study results replicated, Athlete A would outperform Athlete B even though it is a “bodyweight” test.

3. Bodyweight pullups

Athlete A
Bodyweight 150 lbs
Weighted Pull-up 200 lbs
Bodyweight Pull-up = 75% of 1RM

Athlete B
Bodyweight 150 lbs
Weighted Pull-up 225 lbs
Bodyweight Pull-up = 67% of 1RM

If the study results replicated, Athlete B would outperform Athlete A even though it is a “bodyweight” test. 

4. Box Jumps

Athlete A
Max Box Jump = 48”
24” Box Jump = 50% of Pmax

Athlete B
Max Box Jump = 53”
24” Box Jump = 45% of Pmax

This test would be approaching the 40% threshold, so the predictive power of Pmax is becoming less likely.

5. Wall Balls

Athlete A
Max Wall Ball Height = 30’
10’ Wall Ball = 33% of Pmax

Athlete B
Max Wall Ball Height = 35’
10’ Wall Ball = 28% of Pmax

Since the percentage of Pmax is significantly lower, maximal power is less predictive of muscle endurance performance. Athlete A has a chance.

6. Front Squats

Athlete A
1RM Front Squat 300 lbs
100 lb Front Squat = 33% of 1RM

Athlete B
1RM Front Squat = 400 lbs
100 lb Front Squat = 25% of 1RM

Since the percentage of 1RM is significantly lower, Athlete A has a chance in this muscle endurance test.

Below the 40% threshold, the researchers started to see variability in muscle endurance test performance.

Above the 40% threshold, 1RM predicted which athlete would get more reps.

If you are constantly confronting loads that are greater than 40% of your 1RM, you might be able to perform better in CrossFit by just getting stronger.