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ULTIMO FASCICOLOTHE JOURNAL OF SPORTS MEDICINE AND PHYSICAL FITNESS

Rivista di Medicina, Traumatologia e Psicologia dello Sport


Indexed/Abstracted in: Chemical Abstracts, CINAHL, Current Contents/Clinical Medicine, EMBASE, PubMed/MEDLINE, Science Citation Index Expanded (SciSearch), Scopus
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The Journal of Sports Medicine and Physical Fitness 1999 Giugno;39(2):83-92

 ORIGINAL ARTICLES

Hemoglobin near-infrared spectroscopy and sur­face EMG ­study in mus­cle ischae­mia and fatigu­ing iso­met­ric con­trac­tion

Alfonsi E. 1, Pavesi R. 2, Merlo I. M. 1, Gelmetti A. 3, Zambarbieri D. 2, Lago P. 3, Arrigo A. 1, Reggiani C. 4, Moglia A. 1, 5

1 Clinical Neurophysiology Unit, Fondazione “Istituto Neurologico C. Mondino”, IRCCS, University of Pavia, Pavia, Italy;
2 Department of Systems and Computer Science, University of Pavia, Pavia, Italy;
3 Policlinico “S. Matteo”, IRCCS, University of Pavia, Pavia, Italy;
4 Department of Human Physiology, University of Pavia, Pavia, Italy;
5 Interdisciplinar Center of Sport Medicine, University of Pavia, Pavia, Italy

Background. To ­assess how mus­cle ischae­mia and iso­met­ric fatigu­ing con­trac­tion influ­ence oxy­gen con­tent in stri­at­ed mus­cle.
Methods. We simul­ta­ne­ous­ly meas­ured chang­es in hemo­glo­bin ­near-­infrared (NIR) spec­tros­co­py and in sur­face EMG ­before, dur­ing, and ­after mus­cle ischae­mia and ischae­mia ­plus mus­cle iso­met­ric fatigu­ing con­trac­tion. Seventeen ­healthy ­male sub­jects (age ­range: 19-40 yrs) ­were exam­ined in our Clinical Neurophysiology Unit. Test I (9 sub­jects): hemo­glo­bin NIR spec­tros­co­py and stim­u­lat­ed sur­face EMG ­were meas­ured for 2 min­utes at ­rest, for 4 min­utes dur­ing com­plete ischae­mia of tibi­al­is ante­ri­or mus­cle, and for ­twelve min­utes dur­ing recov­ery. Test II (all sub­jects): hemo­glo­bin NIR spec­tros­co­py and sur­face EMG ­were meas­ured for 2 min­utes ­with the sub­jects per­form­ing ­brief non-fatigu­ing con­trac­tions, for 4 min­utes ­with the sub­ject per­form­ing max­i­mal iso­met­ric con­trac­tion in com­plete ischae­mia, and for ­twelve min­utes dur­ing recov­ery. EMG param­e­ters meas­ured: ­median den­sity fre­quen­cy (MDF); mus­cle ­fiber con­duc­tion veloc­ity (­MFCV). NIR spec­tros­co­py param­e­ters meas­ured: per­cent­age of ampli­tude decre­ment (%AD) and ­nadir ­time (NT) dur­ing ischae­mia and ischaem­ic ­effort; ­half-recov­ery ­time (1/2 RT) ­from ischae­mia ­effort.
Results. At EMG, we ­observed a sig­nif­i­cant ­shift ­towards low­er val­ues of ­both ­MFCV and MDF dur­ing fatigu­ing iso­met­ric con­trac­tion. MDF recov­ery was fast­er ­then ­MFCV recov­ery. At NIR spec­tros­co­py, the 1/2 RT ­slowed a ­fast pat­tern in ­twelve sub­jects and a ­slow pat­tern in ­five. A sig­nif­i­cant rela­tion­ship was ­found ­between AD% and 1/2 RT val­ues of ­test I and AD% and 1/2 val­ues of ­test II. We ­found a pos­i­tive rela­tion­ship ­between NT and 1/2 RT in ­test II.
Conclusions. Surface EMG and hemo­glo­bin NIR spec­tros­co­py can be ­applied simul­ta­ne­ous­ly to eval­u­ate ­both ­fatigue inten­sity and ­blood ­flow chang­es in stri­at­ed mus­cle.

lingua: Inglese


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