| The purpose of the study was to assess the acute effects of the
self-selected regimen of rapid body mass loss (RBML) on muscle performance
and metabolic response to exercise in combat sports athletes. Seventeen
male athletes (20.8 ± 1.0 years; mean ± SD) reduced their body mass by 5.1
± 1.1% within 3 days. The RBML was achieved by a gradual reduction of energy
and fluid intake and mild sauna procedures. A battery of tests was performed
before (Test 1) and immediately after (Test 2) RBML. The test battery included
the measurement of the peak torque of knee extensors for three different
speeds, assessment of total work (Wtot) performed during a 3-min intermittent
intensity knee extension exercise and measurements of blood metabolites
(ammonia, lactate, glucose and urea). Absolute peak torque was lower in
Test 2 compared with Test 1 at angular velocities of 1.57 rad·s-1 (218.6
± 40.9 vs. 234.4 ± 42.2 N·m; p = 0.013) and 3.14 rad·s-1 (100.3 ± 27.8 vs.
111.7 ± 26.2 N·m; p = 0.008). The peak torque in relation to body mass remained
unchanged for any speed. Absolute Wtot was lower in Test 2 compared with
Test 1 (6359 ± 2326 vs. 7452 ± 3080 J; p = 0.003) as well as Wtot in relation
to body mass (89.1 ± 29.9 vs. 98.6 ± 36.4 J·kg-1; p = 0.034), respectively.
As a result of RBML, plasma urea concentration increased from 4.9 to 5.9
mmol·l-1 (p = 0.003). The concentration of ammonia in a post-test sample
in Test 2 tended to be higher in comparison with Test 1 (80.9 ± 29.1 vs.
67.6 ± 26.5 mmol·l-1; p = 0.082). The plasma lactate and glucose responses
to exercise were similar in Test 1 and Test 2. We conclude that the self-selected
regimen of RBML impairs muscle performance in 3-min intermittent intensity
exercise and induces an increase in blood urea concentration in experienced
male combat sports athletes.
Key words: Wrestlers, karatekas, muscular endurance, peak torque,
ammonia, urea.
|
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Mati Pääsuke, Luule Medijainen and Jaan Ereline