When Amazfit signed Josh Kerr back in January ahead of the Millrose Games, we knew Josh was a special athlete. His unrelenting commitment to the details and dedication to optimizing every aspect of his performance was evident in his daily routine. Amazfit is honored to work with Josh as we train, recover, and evolve together.
How Josh Tracked His Training Data
When Josh announced Project 222 in March, our team got in contact with his coach Danny Mackey to see how we could best support his journey towards a world record. Josh received the all-new Cheetah 2 Pro, which he wore with his Helio Arm Band during workouts, and Helio Ring during sleep. Josh's biggest focus with monitoring his data was sleep tracking, since he transitioned into sleeping in an altitude-controlled room up to 10,000 ft. Wearing the Helio Ring to bed allowed Josh to see subtle changes in sleep, recovery, and HRV, while wearing the Cheetah 2 Pro watch and Helio Strap during all his runs and workouts allowed him to monitor his daily effort in training. Josh also had his home-gym set up at sea level, so he could work out in a more rested state if needed.
Josh Kerr's Diamond-Studded Cheetah 2 Pro
What was Josh Kerr wearing when he broke the world record? In collaboration with Perry Jewelry, Amazfit gifted Josh a custom Cheetah 2 Pro with a 10 karat gold bezel, 84 lab-grown diamonds, and an engraved "222" on the clasp. While you usually see sprinters wear watches and jewelry on the start line, it's rare to see a distance athlete wear anything besides a standard GPS watch. Josh changed the game when he wore his watch for his mile world record.
The Race
From the gun, Josh accelerated quickly hitting a max power of 500 Watts. He settled down to the mid-400s, which was sustained evenly throughout the race, then increased slightly during the last 200m. This shows that Josh was able to hit record-breaking speed from the very start, allowing him to tuck behind the pacers and evenly maintain effort without letting the lactic slow him down.
Josh's 400m splits were 55.3, 55.8, 55.4, and 54.9--an incredibly evenly paced race with just enough of a negative split during those final moments. His cadence followed a similar pattern as his power with a quick rise at the beginning, settling down into the 190s, then rising again towards the finish as he accelerated.
Josh's heart rate quickly rose from 123bpm on the start line to 160bpm and hit a max heart rate of 188bpm about 400m into the race. From there, he stayed in the 180s as he settled into an aggressive, but rhythmic pace.
The chart below documents the before (including a stride), during, and after the moment Josh broke the record. The full activity shows about 20 minutes of activity, with 3 minutes and 42 seconds in the middle, featuring his world record.
While a mile is considered middle distance in professional track and field, Josh's metrics indicate his form and efficiency operated closer to that of a sprinter when you compare him to the standard population. Josh hit a max stride length of 2.2m, and hovered around 200 milliseconds for his ground contact time. For context, elite sprinters like world record holder in the 100m and 200m Usain Bolt hit up to 2.7m in stride length and have an extremely low ground contact time of about 100ms. The longer your stride length and the lower your ground contact time, the faster and more efficient you are as a runner.In summary, Josh's race showcased the following metrics:
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Max Heart Rate: 188bpm
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Average Heart Rate: 178bpm
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Start Line Heart Rate: 123bpm
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Max Cadence: 200
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Average Cadence: 194
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Max Power: 500
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200m splits: 27.5, 27.8, 27.9, 27.9, 27.7, 27.7, 27.5. 27.4
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400m Splits: 55.3, 55.8, 55.4, 54.9
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Max Stride Length: 2.2 meters (7.25 feet)
What's Next for Josh Kerr?
For an athlete as driven as Josh, the work is never done. While he's taking time to celebrate and absorb his incredible achievement, he has his eyes set on the
Commonwealth Games beginning July 23rd through August 2nd. He is currently deciding his fall race calendar, and has his eyes set on several major moments.
Josh Kerr has rewritten history, and we can't wait to see what he does next. We're proud to support Josh every step of the way as he gets closer to the LA 2028 Olympic Games.
