HEMOGLOBIN/MYOGLOBIN O2 DESATURATION DURING ALPINE SKIING STRATIFIED BY AGE.

Abstract

1772 Muscle contraction patterns and extreme joint angles observed during alpine skiing may impede blood flow and subsequent oxygen delivery affecting hemoglobin/myoglobin deoxygenation(OD) in working muscles. Although biomechanical analysis of giant slalom (GS) and slalom (SL) have previously been investigated, the relationship between the GS and SL for ΔOD in junior alpine skiers, stratified by age, has not been reported. Thirty individuals ranging in age from 9 to 17 years (13.5±2.3) were grouped by class and age: Group I, (J1; 17 to 18 yrs) and (J2; 15 to 16 yrs); Group II, (J3; 13 to 14 yrs); Group III, (J4; 11 to 12 yrs) and (J5; 9 to 10 yrs). Duel wavelength spectrophotometry (NIRS), was used to measure ΔOD in the capillary bed of the vastus lateralis during GS and SL events. MaximalΔOD (CI) was determined in the laboratory during thigh cuff ischemia. ANOVA revealed 33.8% greater ΔOD during the GS for all groups( p<0.05). When stratified by age, significant differences were observed for relative ΔOD (% CI) between groups as indicated by: Group I, GS-70.7% vs SL-52.1%; Group II, GS-82.9% vs SL-66.1%; Group III, GS-79.3% vs SL-71.4%. The greater ΔOD during GS is consistent with the hypothesis that oxygen delivery and blood flow are compromised due to the deeper joint angles and longer duty cycles during this event.