If Sally has a fitness goal to improve her mile run time from 10 minutes and 15 seconds per mile to below 8 minutes and 30 seconds per mile in 3 months, which

training plan using the heart rate zones would best help her achieve her goal?

Sally should do all her workouts in zone 4 in order to increase her anaerobic

threshold.

Sally should most of her workouts in the 5th zone to increase speed.

Sally should do most of her workouts in the 1st and 2nd zones to increase her

ability to withstand fitness activity.

Sally should do most of her workouts in zone 3, but have some of her workouts

go in to zone 4 in order to increase her anaerobic threshold.