High-Velocity, Accentuated Eccentric, or Maximal Elastic Band Resistance Training? Effects of Resistance Training Modalities on Bone Health, Isokinetic Strength, and Systemic Biomarkers in Sedentary Older Adults: A Comparative Study

<b>Objectives</b>: To examine three elastic band resistance training (EB-RT) modalities-high-velocity (HVRT), accentuated eccentric (Aecc), and maximal strength (Max)-on bone health, strength, redox-inflammatory profile, and neuroplasticity in sedentary older adults. <b>Methods</b>: Sixty-one participants (69.41 ± 4.61 years) were randomly assigned to HVRT (<i>n</i> = 21), Aecc (<i>n</i> = 13), Max (<i>n</i> = 10), or passive controls (<i>n =</i> 17). Training was conducted three times a week for 16 weeks. Sessions included four sets of alternating upper- and lower-limb EB exercises, with intensity guided by the OMNI-RES EB scale. HVRT emphasized explosive concentric actions [~70% one-repetition maximum (1RM); 3-4 rating of perceived exertion in the first repetition (RPE-1)]. Aecc performed 5 s eccentric overload [>100% 1RM; 7-8 RPE-1]. Max employed controlled 2 s concentric/eccentric actions [~80-85% 1RM; 7-8 RPE-1]. <b>Results</b>: All training groups improved isokinetic strength (<i>p</i> < 0.01, <i>g =</i> 0.91-2.40). HVRT increased brain-derived neurotrophic factor (BDNF) (<i>p</i> = 0.019, <i>g</i> = 0.42) and glutathione peroxidase (GPx) (<i>p</i> < 0.001, <i>g</i> = 0.31). Aecc elicited the strongest osteoanabolic and antioxidant effects (P1NP, <i>p =</i> 0.001, <i>g</i> = 1.21; β-CTX, <i>p <</i> 0.001, <i>g</i> = 1.82; F2-isoprostanes, <i>p =</i> 0.007, <i>g</i> = 0.94). Max induced moderate bone turnover benefits (P1NP, <i>p =</i> 0.005, <i>g</i> = 1.08; β-CTX, <i>p <</i> 0.001, <i>g</i> = 1.12), but no GPx or BDNF gains. Controls maintained or declined all variables. <b>Conclusions</b>: EB-RT over 16 weeks improved most outcomes overall, showing modality-specific trends: HVRT favored neuroplasticity, Aecc enhanced redox-inflammatory and bone remodeling responses, and Max improved strength and bone health. These findings support elastic band resistance training as a safe and individualized strategy for healthy aging.