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The Journal of Sports Medicine and Physical Fitness 2003 September;43(3):267-73


lingua: Inglese

Percentual responses proximal to the onset of blood lactate accumulation

Acevedo E. O. 1, Kraemer R. R. 2, Haltom R. W. 3, Tryniecki J. L. 2

1 Department of Exercise Science and Leisure Management, University of Mississipi, MS, USA 2 Department of Kinesiology and Health Studies, Southeastern Louisiana University, Hammond, LA, USA 3 Department of Health Promotion, Branch Medical Clinic, Mayport, FL, USA


Aim. Run­ning at incre­mental veloc­ities prox­imal to the ­onset of ­blood lac­tate accu­mu­la­tion (­OBLA) ­elicits ­linear ­increases in V.O2, and HR, ­while the ­increases in V.E and ­blood ­lactic ­acid con­cen­tra­tions (BLa) are cur­vi­linear. In addi­tion, ­effort ­sense is ­often meas­ured in the ­field ­with the tra­di­tional 15-­point ­scale Rat­ings of Per­ceived Exer­tion ­scale, ­increases lin­e­arly ­whereas the per­cep­tual ­response of ­affect ­seem to ­decrease in a non­linear ­manner. ­This ­study exam­ined the ­changes in ­effort ­sense (RPE) and ­affect, uti­lizing the ­Feeling ­Scale (FS), at 3 run­ning inten­sities prox­imal to the ­onset of ­blood lac­tate accu­mu­la­tion. In addi­tion, the rela­tion­ship ­between ­these per­cep­tual ­responses and V.E, V.O2, HR, RER, and BLa ­were exam­ined.
­Methods. ­Eleven ­highly-­trained dis­tance run­ners (V.O2max = 67.65±1.24) par­tic­i­pated in 2 ses­sions of ­data col­lec­tion. ­During Ses­sion 1 sub­jects per­formed a dis­con­tin­uous pro­gres­sive tread­mill pro­tocol to deter­mine ­peak ­aerobic ­power. ­After ­each ­stage a ­finger tip ­blood ­sample was ­taken to deter­mine BLa. A regres­sion ­line ­between the 2 suc­ces­sive work­loads ­that pro­duced BLa ­above and ­below 4 mM was cal­cu­lated to pre­dict the V.O2 ­that ­would gen­erate 4mM BLa (V.O2 @ 4 mM). ­Within 1 ­week ­each sub­ject ­returned for Ses­sion 2, ­which ­included a 10-min ­warm-up run fol­lowed by 3 sub­max­imal ­runs ­lasting 5 min ­each: the V.O2 at 10% ­below ­OBLA (V.O2 10% ↓), the V.O2 at ­OBLA (V.O2 @ 4 mM), and the V.O2 at 10% ­above ­OBLA (V.O2 10%–). ­During the ­last ­minute of ­each run V.O2, V.E, HR, RER, RPE, and FS ­were ­assessed. In addi­tion, Bla was ­assessed imme­di­ately fol­lowing ­each run.
­Results. ­Results dem­on­strated ­that V.O2 10% ↓, V.O2 @ 4 mM, and V.O2 10% ↑ elic­ited BLa of 2.66±0.33, 3.75±0.40, and 6.10±0.68 mM, respec­tively. In addi­tion, RPE ­increased sig­nif­i­cantly ­from V.O2 10% ↓ to V.O2 @ 4 mM and ­from V.O2 @ 4 mM to V.O2 10% ↑; ­whereas FS dem­on­strated a ­slight ­decrease ­from V.O2 10% ↓ to V.O2 @ 4 mM, and a ­more sub­stan­tial and sig­nif­i­cant ­decrease ­from V.O2 @ 4 mM to V.O2 10% ↑. Cor­re­la­tional anal­yses ­revealed sig­nif­i­cant rela­tion­ships at V.O2 10% ↑. Spe­cif­i­cally, RPE and FS ­were neg­a­tively ­related (r=0.62), ­while RPE and V.O2 ­were pos­i­tively ­related (r=0.53). Cor­re­la­tions ­across all work­loads ­revealed a ten­dency for ­more pow­erful rela­tion­ships to ­exist ­among RPE and phys­io­log­ical ­cues ­than FS and phys­io­log­ical ­cues.
Con­clu­sion. ­This is the ­first ­study to ­directly ­examine ­changes in RPE and FS in rela­tion to the phys­io­log­ical ­threshold for anaer­obic metab­olism, Bla, ­which ­responds to ­linear ­increases in exer­cise inten­sity in a cur­vi­linear ­manner. ­Results sup­port pre­vious inves­ti­ga­tions sug­gesting a ­that the ­drop in FS has ­some dis­tinc­tion ­from the ­increase in RPE and ­that FS may be ­more sen­si­tive to the ­onset of anaer­obic metab­olism. More­over, the rela­tion­ship of RPE to FS at V.O2 10% ↑, but not V.O2 10% ↓ and V.O2 @ 4 mM, sup­ports the hypoth­esis ­that the ­unique var­i­ability of FS is dimin­ished at ­higher inten­sities of exer­cise ­when phys­io­log­ical ­cues are unam­big­uous.

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