Muscle force output is characterised by constant fluctuations, which have traditionally been quantified during targeted isometric contractions according to their magnitude.
A low magnitude of force fluctuations (i.e. greater steadiness) is correlated with better performance in a variety of activities of daily living, including static balance (measured as postural sway). The importance of force control is illustrated by the fact that it is often more strongly associated with performance of activities of daily living than maximal strength.
Fluctuations in muscle force have recently started to also be quantified according to their temporal structure, or “complexity”. The complexity of force output is believed to reflect the ability to rapidly and accurately adapt force in response to task demands. It has been suggested that both the magnitude and complexity of force fluctuations should be quantified when investigating force control and its influence on performance of activities of daily living.
A recent study has been the first to demonstrate a relationship between force complexity and performance of an activity of daily living, finding of knee extensor force complexity to be correlated with dynamic balance. Moreover, this correlation was stronger than for the relationship between the magnitude of force fluctuations and dynamic balance.
The purpose of this project is to conduct a series of studies extending this initial observation of a relationships between muscle force complexity and balance.
This will involve firstly, investigating the contribution of muscle force complexity to static balance and secondly, investigating muscle force complexity in other muscle groups and their contribution to dynamic balance. This will involve a variety of advanced physiological techniques, including isokinetic dynamometry and force plates.