The Researchers Behind Interval Walking Training: Prof. Nose, Prof. Masuki, and 20 Years of Science

Meet the scientists who created IWT. Professor Hiroshi Nose and Professor Shizue Masuki at Shinshu University have spent 20+ years proving that interval walking improves health outcomes in adults of all ages.

Interval Walking Training (IWT) was created by Professor Hiroshi Nose and Professor Shizue Masuki at Shinshu University in Matsumoto, Japan. Their 2007 Mayo Clinic Proceedings study proved that alternating fast and slow walking intervals improved cardiovascular fitness more than continuous walking in 250 adults over 5 months. Hiko implements their protocol directly.

Here are the researchers whose work powers every IWT session in Hiko.

Professor Hiroshi Nose — The Father of Interval Walking

Professor Hiroshi Nose leads the Department of Sports Medical Sciences at Shinshu University Graduate School of Medicine in Matsumoto, Japan. He developed Interval Walking Training as a structured exercise protocol designed for general-population health, not elite athletes.

Nose’s landmark 2007 study, published in Mayo Clinic Proceedings, enrolled 250 adults with a mean age of 63 and assigned them to either IWT (alternating 3-minute fast and slow intervals) or continuous moderate walking for 5 months. The IWT group showed significantly greater improvements in peak aerobic capacity, thigh muscle strength, and cardiovascular health markers compared to continuous walkers.

Hiko uses the exact protocol from Nose’s research: 3 minutes of fast walking at 70% or more of peak aerobic capacity, followed by 3 minutes of slow recovery walking. The slow phase is what Nose’s team calls the nikoniko pace — written in Japanese as nikonikopeesu — literally “smiley-face pace,” a comfortable effort where you can hold a conversation easily.

The simplicity of IWT is intentional. Nose designed a protocol that requires no equipment, no gym, and no prior fitness experience. Over two decades, his research group at Shinshu University has expanded the evidence base with thousands of participants across multiple longitudinal studies.

Professor Shizue Masuki — Award-Winning IWT Research

Professor Shizue Masuki is a Doctor of Medicine and Professor at Shinshu University, Department of Sports Medical Sciences. She co-developed IWT alongside Professor Nose and has led critical extensions of the research program.

Masuki’s 2019 paper in Mayo Clinic Proceedings identified high-intensity walking time as the key determinant of IWT health benefits. This finding clarified that the fast-walking intervals — not total walking duration — drive the measurable improvements in fitness and metabolic health. Hiko structures every session around this principle, prioritizing intensity intervals as the core training stimulus.

In 2020, Masuki won the National Academy of Medicine Catalyst Award for Interval Walking Training. The NAM Catalyst Award recognizes innovations with the potential to transform health and medicine globally. This is the highest institutional recognition IWT has received.

Masuki’s research also extends IWT’s evidence into bone health. Her 2024 work demonstrated that interval walking improves bone mineral density and contributes to extending healthy lifespan — a finding particularly relevant for aging populations where osteoporosis risk increases.

Before her IWT work, Masuki researched muscle blood flow regulation during exercise in Nose’s laboratory, giving her a deep physiological understanding of how interval protocols affect the body at the vascular and muscular level.

The USARIEM Team — Military Metabolic Science

While Nose and Masuki developed the walking protocol, a separate line of research at the US Army Research Institute of Environmental Medicine (USARIEM) developed the metabolic equations for load carriage. Hiko is the first app to combine both sciences.

David P. Looney is the lead researcher behind the Load Carriage Decision Aid (LCDA) equations that Hiko uses for calorie calculation. His 2022 paper in Medicine and Science in Sports and Exercise (MSSE, volume 54, issue 4, pages 646-654) presented the heavy backpacking metabolic model that accounts for body weight, load weight, walking speed, and grade.

Looney’s earlier work includes 2019 papers on walking metabolic cost and graded walking energy expenditure. In 2025, Looney’s team published validation data for female energy expenditure (PubMed 40590681), confirming that the LCDA equations hold across sex when properly calibrated.

Hiko applies Looney’s LCDA calculations to every second of your workout. When you combine rucking with IWT intervals, Hiko uses both Nose and Masuki’s protocol structure and Looney’s metabolic equations simultaneously.

How Hiko Brings Both Sciences Together

No other app combines Shinshu University’s Interval Walking Training with USARIEM’s load carriage metabolic science. Hiko merges them into a single workout experience:

IWT protocol from Nose and Masuki: 3-minute fast / 3-minute slow intervals, guided with real-time phase indicators
LCDA metabolic modeling from Looney: Body weight, load weight, speed, grade, and terrain all factor into calorie calculations every second
Combined rucking + IWT: When you carry a load during interval walking, Hiko calculates the metabolic cost of both the load and the intensity phase simultaneously

The nikoniko pace recovery intervals give your body the structured rest that Nose’s research proved essential. The fast intervals deliver the high-intensity stimulus that Masuki identified as the key determinant of health outcomes. And the LCDA layer ensures every calorie number reflects real physics, not generic MET estimates.

Hiko exists because these two research programs — developed independently on opposite sides of the Pacific — complement each other precisely. One tells you how to walk. The other tells you what it costs.

Key Publications

Nose H, Morikawa M, Yamazaki T, et al. “Physical fitness improvement in middle-aged and older adults by interval walking training.” Mayo Clinic Proceedings. 2007.
Masuki S, Morikawa M, Nose H. “High-intensity walking time is a key determinant to increase physical fitness and improve health outcomes after interval walking training in middle-aged and older adults.” Mayo Clinic Proceedings. 2019.
National Academy of Medicine. Catalyst Award 2020 — awarded to Interval Walking Training (Masuki, Nose, Shinshu University).
Masuki S. “Interval walking extends healthy lifespan and improves bone mineral density.” 2024.
Looney DP, et al. “Metabolic costs of military load carriage over complex terrain.” Medicine and Science in Sports and Exercise. 2022;54(4):646-654.
Looney DP, et al. “Female energy expenditure validation for load carriage equations.” 2025. PubMed 40590681.
Looney DP, et al. “Metabolic cost of walking and graded walking.” 2019.

Frequently Asked Questions

Who invented Interval Walking Training?

Professor Hiroshi Nose and Professor Shizue Masuki at Shinshu University in Matsumoto, Japan developed IWT. Their research program has run for over 20 years with thousands of participants. Hiko implements their original protocol.

What is the nikoniko pace in IWT?

The nikoniko pace is the slow recovery phase of Interval Walking Training. The Japanese term means “smiley-face pace” — an effort level comfortable enough to hold a conversation. In Hiko, this is the 3-minute slow interval between fast walking phases. Professor Nose designed it as structured active recovery, not passive rest.

Has IWT won any awards?

Yes. Professor Shizue Masuki received the National Academy of Medicine Catalyst Award in 2020 for Interval Walking Training. The NAM Catalyst Award recognizes health innovations with global transformation potential.

How does Hiko use military metabolic research?

Hiko applies the LCDA equations developed by David P. Looney and the USARIEM team to calculate calorie expenditure from load carriage. When you ruck with IWT intervals in Hiko, the app combines Shinshu University’s walking protocol with USARIEM’s metabolic modeling for accurate energy tracking.