Affiliations: [a] Human Movement Studies Unit, Charles Sturt University,
Bathurst, NSW 2795, Australia
Note: [] Human Movement Studies Unit, Charles Sturt University, Bathurst,
NSW 2795, Australia. Tel./Fax: +61 2 63384505; E-mail: [email protected]
Abstract: The purpose of this study was to examine the concentration of blood
ammonia (NH_3) and lactate (La^-)
responses to separate isokinetic arm exercise (AE) and leg exercise (LE).
Eleven healthy non-trained subjects (aged 18--22~yrs, 5 males, 6 females)
completed 50 maximal effort concentric isokinetic contractions at
60°/sec for preferred arm (elbow joint) and leg (knee
joint) on two separate occasions. Blood was drawn before exercise (Rest),
immediately following exercise (End-Ex) and 10 minutes post-exercise (Post-10)
and analysed for NH_3 and La^-. The
exercise intensity was assessed after exercise by presenting the mean
(± SE) torque output as a percentage of the peak torque
output following the 50 contractions for both AE and LE. The exercise intensity
was 78.3 ± 1.4% AE respectively. The fatigue index is a
ratio of beginning torque to end torque within the exercise period, which was
62.7 ± 3.7% 78.5 ± 2.8%
statistically analysed by ANOVA with repeated measures. There was an increase
in NH_3 following AE between Rest and End-Ex from 92.7
± 7.6 μmol.l^{-1}
to 115.3
± 11.4 μmol.l^{-1},
p < 0.05. There was an increase in La^-
following AE between Rest to End-Ex from 1.6 ±
0.10 mmol.l^{-1} to 2.8 ±
0.24 mmol.l^{-1}, p < 0.05. The
La^- increased for LE between End-Ex and Post-10 from 2.4
± 0.23 to 3.3
±0.41 mmol.l^{-1}, p <
0.05. These data suggest a more severe metabolic stress during
fatiguing concentric isokinetic AE compared with LE and are consistent with
previous findings.
