Metaklei: A Stratification Framework for Differentiating Androgen-Enhanced from Training-Only Skeletal Muscle Memory

The concept of muscle memory describes the enhanced capacity of skeletal muscle to regain size and strength following detraining. While well supported in both animal and human research, current literature largely treats muscle memory as a uniform adaptation, without systematically accounting for prior exposure to exogenous androgens. Most human studies either explicitly exclude individuals with a history of anabolic-androgenic steroid (AAS) use or fail to stratify cohorts according to lifetime androgen exposure, introducing a potentially significant and underappreciated confounding variable. We propose that hypertrophy achieved under androgen-enhanced conditions may result in a qualitatively distinct and more persistent adaptive state than hypertrophy induced by training alone. We conceptualize this persistently elevated physiological reference state as Metaklei, characterized by augmented myonuclear permanence, sustained transcriptional readiness, and long-term epigenetic priming. Failure to distinguish this state from training-only muscle memory may lead to inflated effect sizes, obscured mechanistic interpretations, and incomplete models of human muscle plasticity in retraining studies. This paper introduces Metaklei as a descriptive stratification framework, not as a normative, ethical, or policy-oriented model. The framework is structured along three axes: qualitative differences in myonuclear and transcriptional capacity following androgen-enhanced hypertrophy; methodological bias arising from unrecognized former AAS users within ostensibly drug-free cohorts; and temporal stability, as animal data suggest that androgen-induced myonuclear accretion may persist longer than adaptations achieved through training alone. We call for longitudinal human studies incorporating detailed lifetime androgen exposure histories, stratified analyses, and long-term (>10 years) assessment of myonuclear and epigenetic retention. Recognizing Metaklei as a distinct physiological reference state may refine study design and mechanistic interpretation in exercise physiology, rehabilitation, aging research, and anti-doping science, without presupposing ethical or regulatory conclusions. - Conceptual and methodological framework paper introducing Metaklei as a stratification model for skeletal muscle memory research.