In this thesis, three experiments were conducted to monitor: (i) muscle oxygenation and
electromyographic activity of the biceps brachii after exercise-induced muscle damage
(ii) muscle oxygenation after downhill walking-induced muscle damage, and, (iii)
muscle oxygenation following a bout of vigorous concentric exercise.
Maximal eccentric exercise (EE) of biceps brachii resulted in significantly increased
mean resting oxygen saturation and decreased deoxyhaemoglobin. During isometric
contractions at 50% and 80% of subjects’ maximum voluntary torque (MVT), oxygen
desaturation and resaturation kinetics and volume were significantly decreased after EE,
and these declines were significantly prevalent over the following 6 days. Additionally,
a significant shift in median frequency intercept (measured by electromyography; EMG)
towards lower frequencies was observed during isometric contractions at both 50% and
80% MVT after EE in the exercised arm.
After an exhaustive session of downhill walking, another form of EE, resting total
haemoglobin and oxyhaemoglobin decreased. Furthermore, during isometric
contractions at 30%, 50% and 80% of MVT, prolonged and significant increases were
observed in oxygen desaturation and resaturation kinetics and volumes after ambulatory
EE. In contrast to the two EE experiments, concentric contractions did not evoke any
prolonged changes in muscle oxygenation.
Collectively, the findings of this thesis revealed significant and prolonged changes in
muscle oxygenation at rest and during exercise, following sessions of strenuous
eccentric exercise. Although not clear, the possible mechanism responsible for the
changes in muscle oxygenation after EE could be increased resting muscle oxygen
utilization due to probable muscle damage and a subsequent requirement of energy
demanding repair processes. Concentric exercise resulted in fatigue, but it did not affect
muscle oxygenation. Although a prolonged reduction in EMG median frequency
intercept was observed after EE, this was not closely time-associated with the
biochemical, anthropometric or functional markers of muscle damage.