Parker wants to improve their muscle ENDURANCE.

Parker currently lifts every other day for each muscle group, with heavy weights at 60-90% of their 1 RM while completing 2 sets of 15 repetitions.

What part of the FITT principle is Parker not correctly following to improve their muscle ENDURANCE?

1. Frequency
2.Time
3.Parker is following the FITT principle for Endurance
4. Intensity