This report describes a temporally based method for identifying repetitive firing of motor units. This approach is ideally suited to spike trains with negative serially correlated inter-spike intervals (ISIs). It can also be applied to spike trains in which ISIs exhibit little serial correlation if their coefficient of variation (COV) is sufficiently low. Using a novel application of the Hough ...

Fall accidents are a significant problem for the elderly, in terms of both human suffering and economic losses. Localized muscle fatigue is a potential risk factor for slip-induced falls as muscle fatigue adversely affects proprioception, movement coordination and muscle reaction times leading to postural instability and gait changes. Specifically, fatigue in ankle is associated with decline in...

This paper examines the physiological mechanisms responsible for differences in the amplitude of force fluctuations between young and old adults. Because muscle force is a consequence of motor unit activity, the potential mechanisms include both motor unit properties and the behavior of motor unit populations. The force fluctuations, however, depend not only on the age of the individual but als...

Compound muscle action potential (CMAP) and motor unit number estimation (MUNE) are electrophysiological techniques that can be used to monitor the functional status of a motor unit pool in vivo. These measures can provide insight into the normal development and degeneration of the neuromuscular system. These measures have clear translational potential because they are routinely applied in diag...

The purpose of this study was to examine the effects of an 8-week resistance training program on the relationship between average motor unit firing rates and recruitment threshold in the vastus lateralis. Eleven untrained men (mean ± SD age = 22.5 ± 4.2 years) volunteered to perform resistance training three times per week for 8 weeks. At the end of each week during the training, the subjects w...

Test-retest reliability was assessed for parameters describing motor unit action potential shapes, obtained from multi-channel surface EMG signals.

Motoneurons receive synaptic inputs from tens of thousands of connections that cause membrane potential to fluctuate continuously (synaptic noise), which introduces variability in discharge times of action potentials. We hypothesized that the influence of synaptic noise on force steadiness during voluntary contractions is limited to low muscle forces. The hypothesis was examined with an analyti...

Dystrophic muscle shows increase in fibre density, abnormally low jitter in some recordings and more often increased jitter. The cross section of the motor unit has normal length. There are no signs of abnormal volume conduction characteristics. The increased fibre density is believed to be due to localised increase in the number of muscle action potential generators. The findings are compatibl...

All muscle contractions are dependent on the functioning of motor units. In diseases such as amyotrophic lateral sclerosis (ALS), progressive loss of motor units leads to gradual paralysis. A major difficulty in the search for a treatment for these diseases has been the lack of a reliable measure of disease progression. One possible measure would be an estimate of the number of surviving motor ...