Age-related Changes in Motor Function (I). Mechanical and Neuromuscular Factors
Int J Sports Med DOI: 10.1055/a-1144-3408This two-part narrative review aims to provide an insight into the age-related
mechanical and neuromuscular factors contributing to: (1) decreased maximal
muscle strength and power; (2) decreased force control; and (3) increased
fatigability. Structural and functional changes from the macro-level of the
muscle-tendon unit to the micro-level of the single muscle fibre have been
reviewed and are described. At the muscle-tendon unit level, muscle volume,
thickness and cross-sectional area, as well as pennation angle and fascicle
length all decrease as part of the natural ageing process. These changes
negatively affect muscle quality, muscle and tendon stiffness and
Young’s modulus and account for impairment in motor performance. A
progressive age-related alteration in neuromuscular function is also
well-established, with reduction in number and firing rate of the motor unit,
contractile velocity and specific tension of muscle fibres, and stability of
neuromuscular junction. These could be the result of structural alterations in
the: (i) motor neuron, with number reduced, size and collateral sprouting
increased; (ii) neuromuscular junction, with decreased post-synaptic junctional
fold and density of active zones and increased pre-synaptic branching and
post-synaptic area...
Source: International Journal of Sports Medicine - Category: Sports Medicine Authors: Wu, Rui Vito, Giuseppe De Delahunt, Eamonn Ditroilo, Massimiliano Tags: Review Source Type: research