The quality and reliability of short videos about muscle strain on Bilibili and TikTok: Cross-sectional study.

Muscle strain-related information is extensively shared on short video platforms, yet the quality and reliability of such content remain unassessed. This study aimed to evaluate the quality and reliability of muscle strain videos on Bilibili and TikTok. A total of 157 eligible videos were assessed using the Global Quality Score (GQS) and modified DISCERN (mDISCERN) scales. Videos were graded as high (GQS 4 to 5, mDISCERN 4 to 5), medium (GQS 3, mDISCERN 3) or low (GQS 1 to 2, mDISCERN 0-2) based on information completeness, logicality, source reliability, and objectivity. Bilibili's video quality was predominantly medium to high, while TikTok's quality showed polarization with more medium and low-scoring content. Professional institution-generated videos and scientific introduction-themed content achieved the highest scores; therapeutic content accounted for 82.8% of all videos but was mostly low to medium in quality, and causal content only made up 2.5%. TikTok had significantly higher user interaction metrics than Bilibili (all P < .05), and professional individual creators had higher video sharing volumes than professional institutions (P = .034). GQS was strongly positively correlated with mDISCERN (R = 0.86, P < .001); all interaction indicators were highly positively correlated (R ≥ 0.81, P < .001), and no significant correlation was found between interaction metrics and content quality (e.g., correlation coefficient between GQS and likes = 0.18, P > .05). Bilibili demonstrated a better overall quality of muscle strain videos compared to TikTok, which exhibited a more polarized quality distribution with a higher proportion of low-quality content. TikTok showed significantly higher user interactivity, but engagement metrics were not associated with content quality. Both platforms presented an unbalanced topic supply, with an overrepresentation of therapeutic content and a severe scarcity of causal content. These findings highlight the need for optimizing the ecosystem of health popular science short videos, providing targeted references for the public, platforms, and professionals to improve the quality and reliability of muscle strain information online.