Participants and design
Thirty-nine healthy adults sat upright and performed voluntary side-bending of the trunk for 5 minutes (15° to each side, 60 movements per minute, paced by a metronome). During the movement a rod-shaped applicator was held against the right lumbar paraspinal muscles. The applicator displays the applied load continuously and accepts tips of different diameters.
Muscle hardness at the contact site was measured with a hardness meter before and after each condition, using the mean of five consecutive readings. The post/pre ratio was compared across conditions with repeated-measures analysis of variance.
Conditions compared
| Factor | Levels |
|---|---|
| Applied load | None, 250, 500, 750 and 1,000 gf. The original paper reports these force conditions in g; this site gives them in gf. |
| Contact tip diameter | 1, 2 and 3 cm |
| Common to all conditions | Seated; voluntary side-bending; 5 minutes |
Results
Hardness decreased from before to after in all four loaded conditions; the unloaded movement alone was the exception. The post/pre ratio was lower at 500 gf and 750 gf than at 250 gf.
For contact size, hardness decreased with all three tips, and the post/pre ratio was lower with the 1 cm and 2 cm tips than with the 3 cm tip.
The post/pre ratio did not differ significantly by sex and was not significantly correlated with BMI or baseline hardness. The authors conclude that the largest effect was obtained at 500–750 gf with a 1–2 cm tip. Test statistics are reported in the paper.
Scope and next steps
This study defines a working dose range in healthy lumbar muscle, for a single session and an immediate outcome.
Research direction
A proposed collaborative study would test the same parameters in people with pain, in other body regions, and over a longer observation period. Two questions suit a partner laboratory well: how much applied force varies between certified practitioners, and how the time course of hardness relates to symptoms.
Ethics and reporting
Please consult the paper for the safety assessment methods and observation period, ethics approval, funding and competing interests. Related conference presentations are listed under Publications .
Sources
- Sugimoto S, Sakato T, Nakayama T, et al. Effect of Kanshoho on lumbar muscle tone [in Japanese]. Journal of Physical Therapy Fundamentals. 2025;28(1):32–38. doi:10.24780/jjptf.JJPTF_2023-17
- Nakayama T, Sugimoto S, Sakato T, et al. Conference abstract P-028, 42nd Kanto-Koshinetsu Block Physical Therapy Congress, 2023 (in Japanese)
- Sugimoto S, Sakato T, Furuyama T, et al. Conference abstract YP-26-4, 10th Annual Meeting of the Japanese Society of Physical Therapy for Prevention, 2023 (in Japanese)
Sections marked “Research direction” describe hypotheses and proposed studies for discussion with collaborators. Observations are presented with their participants, methods and sources.
Last updated: 2 October 2026