The influence of acute hypoxic exposure on isokinetic muscle force production
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Data
2014
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Resumo
To investigated whether an acute hypoxic stimulus affects muscle strength development assessed by isokinetic
dynamometry during maximal knee extension. A total of 15 healthy young men participated in this study (61.9 ± 6.1 kg;
1.72 ± 0.08 m; 20.9 ± 2.6 years). We evaluated knee extension and flexion isokinetic dynamometer performance in
normoxic and hypoxic conditions. The analyzed parameters, for concentric contraction, were peak torque and total work
measured at 1.05 and 5.23 rad/s; and fatigue index measured at 5.23 rad/s. During isokinetic testing, heart rate and
oxygen saturation (SpO 2 ) were monitored. Hypoxic conditions (3,600 m) were simulated, via a mixing chamber, with the
dilution being constantly controlled by a PO 2 probe. Test reproducibility results (test-retest) for all isokinetic knee
parameters were classified as moderate to almost perfect (ICC = 0.694 to 0.932). SpO 2 was 88.4 ± 3.4% in the hypoxic
condition and 97.1 ± 0.7% in the normoxic condition (p = 0.000, effect size = 0.87). Heart rate was not
significantly different between normoxic and hypoxic conditions at the end of the test. There were no significant
differences in isokinetic variables evaluated for the extensor and flexor muscles at concentric contraction between the
normoxic and hypoxic conditions. Our findings indicate that reduced arterial oxygenation per se has no effect on the
muscular isokinetic strength of the knee extensors.
Descrição
Palavras-chave
Normoxia, Oxygen saturation, Isokinetic dynamometry, Knee muscle strength
Citação
IVAMOTO, Rafael Kenji et al. The influence of acute hypoxic exposure on isokinetic muscle force production. SpringerPlus, London, v. 3, n. 604, p. 1-5, 2014.