["The Journal of Physiology, Volume 604, Issue 7, Page 2796-2815, 1 April 2026. ", "\nAbstract figure legend Ageing is associated with reduced motor neuron excitability and lower motor unit (MU) discharge rates, contributing to impaired voluntary force production. Using high‐density surface EMG and longitudinal motor unit tracking, we show that 4 weeks of isometric strength training increases discharge rates and estimates of persistent inward currents (PICs) in older adults, reflecting enhanced intrinsic motor neuron excitability and synaptic input. These neural adaptations were associated with a 17.6% increase in maximal voluntary force, demonstrating that the ageing neuromuscular system retains a robust capacity for functional adaptation in response to targeted strength training.\n\n\n\n\n\n\n\n\n\nAbstract\nAgeing induces structural and functional changes in the neuromuscular systems that impair voluntary force production, compromising daily function and wellbeing. We examined whether older adults preserve the capacity for motor unit adaptations to a short‐term strength training intervention previously shown to enhance neural drive to muscle in young adults. Twenty‑three older adults were assigned to a training group (INT, n = 13, 71 ± 4 years of age) or a control group (CON, n = 10, 69 ± 2 years of age) and completed pre‐ and postintervention assessments of ankle dorsiflexor maximal voluntary force (MVF). Motor unit behaviour was analysed from high‑density surface EMG recorded from tibialis anterior during submaximal trapezoidal contractions. The INT group performed a 4 week supervised isometric strength training programme, whereas the CON group maintained habitual activity. High‑density surface EMG signals were decomposed into individual motor units, tracked longitudinally across sessions. Training increased MVF by 17.6% and enhanced motor unit discharge rate at recruitment (+8.2%, P = 0.031) and constant force (+11.3%, P < 0.001), without changes in recruitment or derecruitment thresholds. Estimates of persistent inward currents (delta frequency) increased (+1.0 pulses per second) and were positively correlated with changes in discharge rate, which, in turn, were correlated with gains in MVF (rrm = 0.54–0.57, P < 0.05). This pattern suggests that enhanced intrinsic excitability and synaptic input to motor neurons contributed to improvements in strength. These results demonstrate that, despite age‐related motor unit remodelling, the ageing nervous system remains responsive to targeted strength training, preserving the capacity for meaningful neural adaptations.\n\n\n\n\n\n\n\n\n\nKey points\n\nWe assessed whether a short‐term intensive strength training intervention, previously shown to increase spinal motor output to the muscle significantly in young adults, would also be effective in older adults.\nHigh‐density surface EMG was used to identify and longitudinally track the same motor units before and after a 4 week isometric strength training intervention.\nWe found significant strength gains in older adults, with the increase in muscle force output being positively associated with higher motor unit discharge rate and persistent inward currents, indicating that neural drive enhancement was a key contributor to the observed improvements in force.\nDespite age‐related motor neuron remodelling, the older nervous system remains highly responsive to strength training, exhibiting qualitatively similar but attenuated motor unit adaptations compared with young adults.\n\n\n"]