Age-related strength loss may reflect morphological and neural adaptations that differ between muscles. However, it is unclear how ageing affects motor unit (MU) discharge rate modulation and estimates of persistent inward currents (PICs) across contraction levels. Thirty young (24 ± 4 years) and thirty older adults (73 ± 4 years) underwent magnetic resonance imaging and performed unilateral isometric dorsiflexion and knee ext...

Neuromuscular function is critical for independence in ageing, yet asymmetries between dominant and non-dominant limbs, arising from central or peripheral mechanisms, are not well understood. This study examined age- and limb-related differences and motor unit (MU) firing behaviour of the vastus lateralis under tasks of varying difficulty. Twenty-one young (22 ± 4 years; 15 M, 6F) and seventeen older adults (74 ± 5 years; 12 M...

Resistance exercise (RE) enhances functionality in older adults and has proven effective as a means of cross-education in scenarios of unilateral disuse. However, the extent to which older adults demonstrate cross-limb transfer at the motor unit (MU) level following a single bout of unilateral RE is unclear. Thirteen healthy older adults (74.9 ± 4.8 years; 5 females) underwent bilateral neuromuscular assessments pre- and post-...

Although muscle atrophy may partially account for age-related strength decline, it is further influenced by alterations of neural input to muscle. Persistent inward currents (PIC) and the level of common synaptic inputs to motoneurons influence neuromuscular function. However, these have not yet been described in the aged human quadriceps. High-density surface electromyography (HDsEMG) signals were collected from the vastus la...

Long-term exercise training has been considered as an effective strategy to counteract age-related hormonal declines and minimise muscle atrophy. However, human data relating circulating hormone levels with motor nerve function are scant. The aims of the study were to explore associations between circulating sex hormone levels and motor unit (MU) characteristics in older men, including masters athletes competing in endurance a...

Motor unit (MU) expansion enables rescue of denervated muscle fibres helping to ameliorate age-related muscle atrophy, with evidence to suggest master athletes are more successful at this remodelling. Electrophysiological data has suggested MUs located superficially are larger than those located deeper within young muscle. However, the effects of ageing and exercise on MU heterogeneity across deep and superficial aspects of va...