Evidence map›Paper›PMID 41798489›Full record

ArticleCureus2026

Striking Concerns: Reduced Protection in Older Kendo Helmets.

Ellison Wong, Harrison G Chu, Alexis Leo, Gary Chu

Abstract read
In one paragraph

Article in Cureus, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

0numbers the graph read from it
0cells of the map it votes in
0citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

4 authors.

Ellison WongMedicine, California Northstate University College of Medicine, Elk Grove, USA.
Harrison G ChuMedicine, California Northstate University College of Medicine, Elk Grove, USA.
Alexis LeoMedicine, California Northstate University College of Medicine, Elk Grove, USA.
Gary ChuInternal Medicine, California Northstate University College of Medicine, Elk Grove, USA.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundProtective headgear in many sports, such as cycling and skiing, is subject to clear recommendations regarding replacement intervals due to material degradation over time. In contrast, kendo helmets (men) lack evidence-based guidance on service life, despite repeated exposure to high-energy impacts during regular practice. In our prior study, we noted that new kendo helmets of different stitch patterns absorb kinetic energies differently.  Objective: To evaluate the effectiveness of older kendo helmets compared to new helmets in mitigating impact forces that could lead to sports-related concussions in kendo.  Methods: We collected data from seven kendo practitioners and collected over 1,900 strikes using a bamboo sword (shinai) on the same sensor-equipped mannequin from our prior study on five helmets over five years old with a 6-mm stitch pattern, tested under controlled conditions simulating realistic impacts encountered in kendo practice, using the same protocol as our prior study.  Results: Older helmets consistently demonstrated lower energy absorption, exhibiting statistically significant higher mean g-forces, with a 95% confidence interval (CI), compared to new helmets with different stitch patterns (2 mm, 6 mm, and 9 mm) from our prior study (p < 0.001). Older helmets recorded an average of 17.9 g, compared with prior study values of 13.5 g for 9-mm helmets, 13.9 g for 6-mm helmets, and 14.7 g for 2-mm helmets (p < 0.001). This corresponds to respective decreases in energy absorption of 32.8%, 29.0%, and 22.0%. A comparison of the worst-performing old helmet (Old Helmet 3) with the best-performing new helmet (9-mm stitching) showed a reduction of 36.7% (18.5 g vs. 13.5 g).  Conclusions: These findings indicate that older kendo helmets provide substantially reduced protection (22%-36.7%) compared to new helmets. Given the frequency of head impacts in kendo and the reduced energy absorption of older helmets, continued use of aged equipment may pose a safety risk. The results highlight the need for evidence-based recommendations regarding helmet replacement intervals in kendo to enhance practitioner safety.

Indexed as

concussion preventionequipment safetyhelmet designhelmetshelmet safetykendomartial artsold equipmentprotective gearsafety standards

Identifiers

PMID41798489
PMCPMC12964322

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.