Reducing the energy cost of running using a lightweight, low-profile elastic exosuit.

Only eight healthy male participants were tested, so the results may not apply to women, older adults, injured runners, or patients. The main comparison across the three band stiffnesses and no-suit showed no significant difference in metabolic rate, so the suit did not demonstrate an overall energy saving. The positive 4.7% reduction was calculated by choosing each participant's best band after seeing the metabolic data, which can inflate the apparent effect. The suit was tested only while running at 2.5 m/s for 5 min, so it says nothing about walking, other speeds, or daily use. The device changed stance duration in some conditions, and the authors state that the assistive force could not be separated from spatiotemporal changes as the cause of metabolic reduction. For three participants, the highest force came from the medium-stiffness band rather than the highest-stiffness band, so band stiffness did not reliably predict assistance. The Discussion calls the MED stance duration 3.2% shorter than no-suit, but the Results and Table 2 report 325.40 ms with MED versus 315.38 ms without the suit.

The paper lists funding from the Ministry of Trade, Industry and Energy, Chung-Ang University, and the National Research Foundation of Korea.

Do not conclude the exosuit reliably lowers running energy cost. Across the three band stiffnesses, metabolic rates did not vary significantly, and the 4.7% reduction came from choosing each runner's best band after seeing the data.