8 x 400 m Track Workout, May 31, 2019

Anaerobic Threshold (AT) Workouts

AT workouts are an important component of distance training because they improve our muscles’ ability to convert glucose into glycogen, and to process lactic acid (a waste product). AT workouts generally include longer repeats (with approximately equal recovery), fartleks, and tempo runs.

Description of Track Workout

This past Friday evening (May 31, 2019), I completed my second 8 x 400 meter track workout since returning from hernia surgery and a metatarsal stress reaction. I felt relaxed and confident during the workout, and really had to mentally focus to control the pace so I did not cross the anaerobic threshold. I decided to upload the data from my Garmin Forerunner 235 to the Garmin Connect website, and compare and analyze the two workouts side-by-side.

Workout No. 1: May 10, 2019

• Weather: Sunny, 70F, 7 mph wind, 73% humidity
• Warmup: 3 miles on Waveny trails at 8 minutes / mile pace
• Workout: 8 x 400 meter repeats on track, target 1:40 minutes, with 90 second recovery
• Cooldown: jog
• Footwear: New Balance 890 v7 (no spikes or flats)
• Training log: Training Recap #13 as of May 19, 2019

Workout No. 2: May 31, 2019

• Weather: Sunny, 75F, 8 mph wind, 47% humidity
• Warmup: 3 miles on Waveny trails at 8 minutes / mile pace
• Workout: 8 x 400 meter repeats on track, target 95 seconds, with 90 second recovery
• Cooldown: jog
• Footwear: New Balance 890 v7 (no spikes or flats)
• Training log: Training Recap #14 as of June 2, 2019

Review and Analytics of Workout

I approached and ran both workouts with the goal to complete 8 repeats, therefore started comfortable and progressed to faster splits with each repeat. I’ve summarized the key data in the table below.

• Times: Overall, stoked with improvement. I ran faster than the target splits, with 97 average split (vs. 1:40 target) and 92 average split (vs. 95 target) for May 10 and May 31 workouts, respectively. That represents a 5 second improvement in 3 weeks. Equally thrilled with 10 second and 7 second progression (improvement from 1st to last repeat), respectively, for 1st and 2nd workout.
• Heart Rate (HR): As expected with the faster May 31 workout, the average and maximum HR increased from the 1st to the 2nd workout. The HR data from the 2nd workout (assuming the Garmin on-wrist HRM is reasonably accurate) seems to indicate that I’m running close to the aerobic/anaerobic line (pun intended). The 3rd workout planned for June 21 will be insightful.
• Cadence: The ideal cadence for a distance runner is 180-184 steps per minute. My average 187 and 185 for the May 10 and May 31 workouts, respectively, are on the high end of the range. However, a simple explanation is that I have relatively short legs relative to my height, so up to 190 should be acceptable.

Summary Workout Data

Notes: Average HR and Maximum HR measured with Garmin Forerunner 235 (on-wrist HRM). Average cadence represents the average number of steps (left and right combined) per minute of running.