Increase of resting muscle stiffness, a less considered component of age-related skeletal muscle impairment

Abstract

Elderly people perform more slowly movements of everyday life as rising from a chair, walking, and climbing stairs. This is in the first place due to the loss of muscle contractile force which is even more pronounced than the loss of muscle mass. In addition, a secondary, but not negligible, component is the rigidity or increased stiffness which requires greater effort to produce the same movement and limits the range of motion of the joints. In this short review, we discuss the possible determinants of the limitations of joint mobility in healthy elderly, starting with the age-dependent alterations of the articular structure and focusing on the increased stiffness of the skeletal muscles. Thereafter, the possible mechanisms of the increased stiffness of the muscle-tendon complex are considered, among them changes in the muscle fibers, alterations of the connective components (extracellular matrix or ECM, aponeurosis, fascia and tendon) and remodeling of the neural pattern of muscle activation with increased of antagonist co-activation.

Age-related reductions in the number of serial sarcomeres contribute to shorter fascicle lengths but not elevated passive tension

“…In old age, there is a loss of muscle mass and alterations to the structural components of the neuromuscular system, impairing contractile function and performance (Power et al, 2013), and there appears to be elevated passive tension for a given muscle length (Marcucci and Reggiani, 2020). Ageing muscles of rodents and humans undergo structural remodelling, whereby muscle fascicle lengths become shorter than in the young (Hooper, 1981;Narici et al, 2003).…”

“…In contrast, Pavan et al (2020) noted no age-related differences at the single-fibre level, but the passive tension of fibre bundles from old humans was greater than that of young humans across all sarcomere lengths, as a result of collagen-induced stiffening of the extracellular matrix. It is important to note that, at the joint level, older adults have greater musculotendinous stiffness (Ochala et al, 2004;Marcucci and Reggiani, 2020), and experience an earlier increase in passive force for a given joint rotation (Gajdosik et al, 2004) than that experienced by young. At the whole-muscle and joint level, muscle architecture contributes relatively more to understanding contractile function than do single-fibre properties (Narici et al, 2016).…”

Acute Effects of Vibration Foam Rolling with Light and Moderate Pressure on Blood Pressure and Senior Fitness Test in Older Women

“…Thus, VR was beneficial for both healthy young adults and older adults. The literature review performed by Marcucci et al indicated that a decline in older adults' joint ROM is associated with changes in their joints, muscles, tendons, and fasciae [18]. More specifically, joint changes include cartilage degeneration, joint capsule thickening, and ligament stiffness increases; muscle and tendon changes include muscle stiffness increases and tendon stiffness decreases; and fascia changes include stiffness increases [18].…”

“…The literature review performed by Marcucci et al indicated that a decline in older adults' joint ROM is associated with changes in their joints, muscles, tendons, and fasciae [18]. More specifically, joint changes include cartilage degeneration, joint capsule thickening, and ligament stiffness increases; muscle and tendon changes include muscle stiffness increases and tendon stiffness decreases; and fascia changes include stiffness increases [18]. Given that the effects of aging on joint ROM occur simultaneously in joints, muscles, tendons, and fasciae, we expected the effectiveness of VR in older adults to be less than that in young adults.…”

“…However, no significant differences in pain, disability, gait, or quality of life were observed between the combined and sole interventions [16]. When soft tissues are under stress, the performance of older adults in terms of compliance, peripheral circulatory function, and the reaction of the nervous system and the autonomic nervous system in the regulation of muscle tension when sensing stimulation input all differed from those of young adults [17,18]. Therefore, the research results claiming benefits of rollers for healthy young adults and athletes may not be applicable to older adults.…”