Development of the “LacttoRUN 30” LT measuring service for distance runners

Many people taking on the challenge of a full marathon have experienced the onset of fatigue and leaden legs around the 30km distance, known as “hitting the wall.” The major cause is believed to be depletion of the body's carbohydrate energy reserves by running too fast. In other words, the key to completing a marathon or reducing times is running as fast as possible without burning carbohydrates. The highest exercise intensity - which for running is the speed or cadence - without using up carbohydrates is called the lactate threshold (LT). Measuring a runner’s LT has previously required using expensive equipment or taking blood samples during exercise, making this data somewhat inaccessible.

At Mizuno, we believed that, in combination with our knowledge of running training, using technology developed by Grace imaging, Inc. - which can measure the lactic acid content in sweat - to make measuring the LT more accessible would provide services attractive to runners. From 2021, Mizuno worked in collaboration with Grace imaging to develop LacttoRUN 30, launching the service in November 2022.

Key points of development

Building the service

It was believed that almost no runners had actually measured their LT. We therefore took the approach not of presenting data in the form “your LT is ABC km/h,” but instead imagining that runners would likely want the optimal cadence and training plan which would lead to time reduction, based on their LT. We therefore built services which include suggesting a race cadence and training plan leading up to an event based on the measured LT.

The service was first provided on a trial basis at the “Running Station” operated by Group company Mizuno Sports Service Co., Ltd. This company already offered cadence and training advice to runners through group training sessions, and we felt that offering this service based on LT would help to provide more accurate advice.
The service achieved an extremely high satisfaction rating among Running Station users, leading to the decision to launch it under the LacttoRUN 30 name.

Service content

Taking around one hour in total, the LacttoRUN 30 service typically follows this process:

1. When a customer visits, the specialist consultant interviews them to obtain basic information such as marathon running history, times, and the event they are aiming for
2. An in-sweat lactic acid measurement device is attached to the upper arm, and a heart rate measurement device is attached to the ear lobe
3. Measurement is conducted while running on a treadmill. Beginning with a gentle jog, the speed is gradually increased to the point the runner finds demanding
4. After measurement is complete, the system prints out the recommended training speed, shoes, etc. to suit the LT and the runner’s goals
5. The specialist consultant provides advice such as on race cadence and daily training based on the printed results

The story behind co-creation with partners

It is not enough for runners to just know their LT; it is also important to be able to apply this knowledge in daily training and races. It was therefore the combination of Grace imaging’s technology and Mizuno’s knowledge of running training that made creating LacttoRUN 30 possible.

Outcomes

Since the service was launched in November 2022, by September 2024 it had been provided to a total of over 600 runners. Customer satisfaction was 9.6 on a 10-point scale, and approximately 30% of customers were repeat users (all figures according to Mizuno research).

Through co-creation between Mizuno, which has cultivated a track record and trust in the sports industry, and companies in Japan and overseas with various resources and innovative technologies, we aim to create and deliver products and services never before seen around the world. We will also continue to support runners by providing services such as LacttoRUN 30.