It has been suggested that the lower oxygen consumption of some
running athletes may be caused by differences in "running style".
In an initial study of treadmill running, segmental potential and
kinetic energy changes were determined using a three-dimensional
fifteen-segment rigid body model of the human body. Energy expenditure was
determined by expired air analysis. The more economic running patterns were
characterised by variations in total body energy of lower amplitude and
greater exchange of energy within and between body segments.
The analytical procedures were develooed in several ways. An automated
system for the breath by breath monitoring of respiratory function and
energy expenditure was developed. Since expired air analysis only enables
the direct measurement of the aerobic component of energy expendi ture, the
validity of a commonly used method for the detection of the "anaerobic
threshold" from respiratory responses was investigated. The validity of
this indirect method was not supported,
A generali sed energy analysis procedure was developed, allowing
constraints on passive energy exchange to be varied.
A method for the determination of the elastic compliance of the knee
extensor muscles was devised and used to incorporate a strain energy
component into the energy analysis. In a further analysis of ten athletes,
energy storage in the elastic components of the knee extensors was found to
be significant during the supoort phase of the running stride. The
inclusion of the elastic comoonents resulted in a significant reduction of
the magnitude of changes in the whole body energy curve even though the sum
of the absolute changes in the partitioned energy components increased.
it was found that there is some correspondance between the magnitude
of passive energy transfers and the "economy" of a running style. Also,
muscle elasticity appears to act as an energy conserving mechanism during
the support phase, reducing both the amount of work and the work-rate
required of the extensor muscles. The additional energy transfers due to
elastic energy storage may account for the unusually high efficiency values
previously reported for running.
A Doctoral Thesis. Submitted in partial fulfillment of the requirements for the award of Doctor of Philosophy of Loughborough University.