Na postagem do blog esse mês vou demonstrar um trabalho feito pelo nosso grupo de pesquisa (LAEF/CNPq - CDS/UFSC) que foi apresentado no último congresso internacional do Colégio Europeu de Ciências do Esporte - European College of Sport Science.
Helal,
LCAS.1, Souza,
KM.1, de Lucas, RD.1, Nascimento,
PC.1, Guglielmo, LGA.1, Denadai, BS.2
1UFSC
(Florianópolis, Santa Catarina, Brazil), 2UNESP (Rio Claro, São
Paulo, Brazil)
Introduction
The
physiological nature of anaerobic work capacity (AWC) has received little
consideration in comparison to critical power (CP). Therefore, the aim of this
study was to analyze the influence of prior exercise performed at different work
rates above CP (with the same AWC rate depletion) on muscle fatigue during a subsequent
isokinetic cycling sprint.
Methods
Fifteen
healthy male subjects (mean ± SD; age, 26.0 ± 3.5 years; weight, 76.6 ± 10.4
kg; height, 178.2 ± 7.6 cm) volunteered to participate in this study. Each subject performed the following
testing stages: 1) a ramp incremental test (25 W/min) to measure maximal oxygen
uptake (VO2max)
and maximal power output (Pmax); 2) a 5-s
all-out isokinetic sprint test at 120-rpm to measure cycling peak torque in control
condition (TCON); 3) four constant work rate tests
performed to exhaustion (over a range of times between 2 and 12 min) for CP and
AWC determination; and 4) two constant work rate tests, each at work rate set to deplete 70% AWC (the
time integral of the work rate above CP consuming 70% of AWC) either 3-min or 10-min,
followed immediately by a 5-s all-out isokinetic sprint test at 120-rpm to
measure cycling peak torque in the experimental conditions (TEXP3min
and TEXP10min). Peak torque was considered as the average of the peak
torque for each leg in all conditions. For comparisons, one-way repeated measure ANOVA followed by Bonferroni’s paired t-test
was used. The level of significance was set at p < 0.05.
Figure 1. Schematic illustration
of the experimental tests. A) 5 s all-out isokinetic exercise performed
immediately after the fatiguing exercise set to deplete 70% W’ in 3 min. B) 5 s
all-out isokinetic exercise performed immediately after the fatiguing exercise set
to deplete 70% W’ in 10 min.
Results
The
VO2max
and Pmax were 3.71 ± 0.49 L.min-1 and 322 ± 26 W,
respectively. The CP and AWC were 207 ± 17 W (r2 = 0.99 ± 0.01; SEE = 3.9 ± 2.7 W; 64.3 ± 2.7% Pmax) and
21.3 ± 4.2 kJ, respectively. The constant work rate tests, which were set to deplete 70% AWC
(14.9 ± 3.0 kJ) in 3 min and 10 min, were performed at 289 ± 25 W (89.8 ± 2.9% Pmax)
and 231 ± 19 W (71.9 ± 2.2% Pmax),
respectively. TEXP3min (108.4 ± 19.8 Nm) and TEXP10min
(112.1 ± 23.0 Nm) decreased significantly (F = 19,68; p < 0,001) in the same
magnitude (p = 0,46) in comparison
to TCON (135.5 ± 20.2 Nm).
Discussion
The
result of the present study is consistent with the idea that AWC is depleted at
a rate that bears some proportionality to the magnitude of the work rate
requirement above CP (Fukuba et al., 2003; Jones et al., 2010). We conclude
that prior exercise above CP produces a similar level of muscle fatigue
independent of the work rate performed when AWC is depleted at the same rate.
References
Fukuba
Y, Miura A, Endo M, Kan A, Yanagawa K, Whipp BJ (2003). Med Sci Sports Exerc,
35 (8), 1413-1418.
