Assessment of Neuromuscular Function with a New Ground Reaction Force Platform Using Power Spectrum Analysis Technique

Abstract

AbstractIn the elderly, sarcopenia is leading to frailty, increased risk of fall and osteoporosis. Two categories of muscle function related tests in geriatrics can estimate physical performance and sarcopenia associated with falls: movement and balance during stance.A newly developed ground force reaction platform measures time series of force against gravity. Power spectral density distribution (PSDD) of these series thus provide some measure of the speed of neuromuscular actions in units of Watt per Hertz [W/Hz] and mechanical power [W] as its integral. Ability to train balance was tested in a young male subgroup of 17 cases and 10 controls. In a community dwelling 1553 men and women age 8 to 89 years were investigated. The number of falls in the past 12 months was assessed in 700 females and 345 males age 50-89. Chair-rise, knee bends, and tandem stance were performed on the platform. Grip strength was dynamometrical measured.After training the mean frequency of the PSDD increased 31% in the young training group vs. the controls. Knee bends power on the platform was less than half in men and women with falls as compared to those without falls. Chair-rise power was not significantly reduced. Maximum force in these groups was significantly reduced only in knee bends (p<0.001). Chair rise time was 23% prolonged in subjects with 2 or more falls (p<0.01). PSDD mean frequency in tandem stance was not significantly associated with falls. Grip strength was also not significantly related to falls, although a trend was seen.Significant short term training effects could be demonstrated on the new platform using PSDD. In the whole study population a large age dependent decline in muscular power was seen between adolescents and elderly. Assessment of number of falls using PSDD provided more pronounced results than the classic chair-rise test.KeywordsSarcopeniamusclespower spectrumfallsosteoporosis