Affiliations: [a] Rehabilitation Research Centre, Discipline of Exercise
and Sport Science, Faculty of Health Sciences, The University of Sydney,
Lidcombe, NSW, Australia
Note: [] Address for correspondence: Sirous Ahmadi, Rehabilitation
Research Centre, Discipline of Exercise and Sport Science, The University of
Sydney, PO Box 170, Lidcombe, NSW 2141, Australia. Tel.: +61 2 9351 9826; Fax:
+61 2 9351 9204; E-mail: sahm8027@mail.usyd.edu.au
Abstract: We investigated the hypothesis that a session of maximal concentric
contraction exercise (CE) might impair muscle oxygenation and muscle blood
flow. Ten healthy males performed a single bout of 70 maximal elbow flexion CE.
Before and after CE on day 1 and over the next two days, maximum voluntary
isometric torque (MVT), plasma creatine kinase activity (CK), serum myoglobin,
elbow joint range of motion (ROM), subjects' perception of muscle soreness
(SOR), and muscle oxygenation kinetics (using near infrared spectroscopy; NIRS)
within biceps brachii were assessed. MVT and ROM decreased while SOR increased
significantly after CE (p<0.05), but recovered within the
next day. There were not any significant changes in CK or myoglobin. Resting
muscle oxygen saturation, oxyhaemoglobin and muscle oxygen uptake increased,
and deoxyhaemoglobin decreased significantly after acute CE, and recovered by
day 2. Although the changes in NIRS-derived variables were not significant in
most conditions during isometric contractions of different intensities
(i.e. 30%, 50% and 80% of MVT), there was a consistent pattern of
change for those variables (i.e. decreasing immediately after CE, recovering on
day 2 and increasing on day 3). Interestingly, the pattern of change in NIRS
parameters mirrored CE-induced changes of MVT. In conclusion, concentric
exercise did not produce prolonged changes in muscle oxygenation. The changes
observed in NIRS-derived variables under resting condition may reflect an
excess post exercise oxygen consumption.
Keywords: Oxygen saturation, blood flow, creatine kinase, myoglobin, near infrared spectroscopy, maximum voluntary contraction
