Spinal Cord Injury (SCI) is a debilitating health condition leading to marked reductions in physical and mental health as well as autonomy and life expectancy. Globally, between 250,000 and 500,000 people suffer a SCI each year, and more than 15,000 Australians live with SCI presently. SCI represents a major health cost to health care systems and families of individuals with SCI.
As a countermeasure, muscle strength training stimulates muscle mass and strength gains, reduces systemic inflammation, and enhances longevity and quality of life. However, it can only be done by those who are able to voluntarily activate their muscles. Nonetheless, previous studies at ECU and elsewhere using neuromuscular electrical stimulation (NMES)-based strength-training have demonstrated remarkable positive effects on muscle hypertrophy and physical health as well as reductions in the negative symptoms of spasticity in people with SCI. But the inability to evoke large muscular forces using this training is a significant factor limiting its success.
One solution may be to train using eccentric muscle contractions, in which muscles generate forces whilst lengthening (as opposed to shortening). Using eccentric training, remarkable strength and muscle hypertrophic responses have been produced even after periods of low-load exercise in non-clinical populations. Additionally, eccentric exercise training profoundly influences physical health through multiple physiological alterations, including improved blood lipid profile, glucose tolerance and bone mineral density, and reduced blood pressure, insulin resistance and systemic inflammation. Thus, eccentric exercise is proven to be a unique and exceptional stimulus for metabolic health improvement when compared to other exercise modes, at least in non-clinical populations.
As no research has examined the effects of NMES-based eccentric strength training in people with SCI, the proposed project will examine the effects of NMES-driven, eccentric “strength training” in people with SCI on muscle mass, strength, physical health, symptoms of spasticity and quality of life. The knee extensor muscles of both legs will be targeted because of their relatively large (potential) muscle mass, which increases the likelihood of triggering systemic changes in cardiovascular health. Both traditional and novel molecular/genetic markers of physical health and metabolic disease (myokines, adipokines, IgG glycosylation) will be assessed alongside blood lactate and heart rate variability measurements in a clinical population for the first time.
We hypothesise that the health and functional benefits of NMES-eccentric training will be substantial and that the training will be demonstrated for use in clinical environments, having important flow-on economic and social benefits.
