HEMOGLOBIN MYOGLOBIN DESATURATION DURING SPEED SKATING/

The characteristic low ''sitting'' position of competitive speed skati ng has been shown to result in a right shifted heart rate-VO2 curve an d elevated submaximal blood lactate values compared with running or cy cling. This is thought to be a consequence of reduced blood flow and s ubsequent oxygen delivery to the exercising muscle while speed skating . Duel wavelength spectrophotometry was used to measure oxygenated and deoxygenated hemoglobin/myoglobin (OD) in the capillary bed of five m uscle groups during in-line skating in upright (US) and low (LS) posit ions. Eight U.S. speed skaters (4 category 1) performed US and LS at 2 .68 and 3.13 m . s(-1) (4% grade) on a wide (2.44 m) treadmill (4 tria ls, 5 min each, 20 min recovery between trials). Expired gas parameter s and blood lactate (LA) concentrations were determined for each trial . Hip and knee angles were measured (PEAK Motion Analysis) and were si gnificantly different in US and LS. For similar oxygen uptake during U S and LS (44.9 +/- 2.79, 45.6 +/- 3.52), heart rate and LA were signif icantly higher during LS (172 +/- 11 vs 179 +/- 10, 4.35 +/- 2.19 vs 8 .70 +/- 3.60). Deoxygenation was significantly greater during LS than during US at both speeds and was greater at 3.13 m . s(-1) (P < 0.05). OD was highly related to LA (r > 0.95) but not to whole body VO2. Blo od volume change was less for LS than for US (P < 0.05). Increased deo xygenation in the capillary bed of the exercising quadriceps during LS versus US is consistent with the hypothesis that blood flow and subse quent O-2 delivery is compromised in the low speed skating position.