| dc.description.abstract | The aim of this study was to investigate the changes in the
concentrations of plasma ammonia and lactate to an anaerobic
exercise response, lasting 90 seconds (s) in duration. The
secondary purpose was to plot this relationship versus muscle
fibre type. Four muscle biopsy sample (7 mg each) were taken
from each subject (n = 25). All muscle samples were stained
using the myosin ATPase pH 10.0> 4.30 and 4.58 technique. This
allowed for differentiation of the ST, FTa and FTb muscle fibres.
Two weeks post surgery blood was sampled from an indwelling
catheter in the antecubital vein before, immediately after, and
four minutes after 90s of exercise. Plasma blood was assayed for
both ammonia and lactate. A one way analysis of variance (ANOVA)
with repeated measures was performed for each metabolite followed
by a Tukey HSD post-hoc test. Correlations were calculated for
exercise, blood, and muscle variables.
Muscle fibre profiles percentages were as follows ST - 53.48
(±8.82), FT - 46.52 (±8.82), FTb (percentage of FT population) -
8.73 (±4.63). The peak power was 6.54 W/kg (±0.83) and the
relative capacity was 687.3 J/kg (±86.3). The capacity score was
higher than scores reported previously for the similar protocol.
Mean plasma ammonia values were 66.65 (±33.45), 130.0 (±37.15),
and 251.8 (±61.82) mol/1 at rest, immediately post-exercise and
at 4 minutes post-exercise respectively. The increase in ammonia
concentration over time was significant (p < 0.01). Mean plasma
lactate values were 1,45 (±.52), 8.30 (±3.11), and 14.08 (±2.62)
mmol/1 at rest, immediately post-exercise and 4 minutes post-exercise
respectively. Lactate increase over time was
significant. There was a significant positive relation between
plasma ammonia and lactate over time (r = .77, p < 0.05).
Regression analysis of percentage FT muscle fibre and ammonia
increase demonstrated a correlation of r = .58 (p < 0.05, one tailed)
amongst those individuals with a 40 percent or greater FT
profile.
It appears that in this study plasma ammonia values were higher
at 4 min. post exercise than at immediately post exercise.
Ammonia and lactate rise linearly with exercise and have been
demonstrated to be related over time. A relation between ammonia
and FT muscle fibre existed in this examination; the greater the
percentage FT fibres the higher the ammonia concentration in
blood plasma. | |
