Differences in lactate exchange and removal abilities between high-level African and Caucasian 400-m track runners

The present study aimed to investigate (1) whether high-level 400-m track runners of different ethnic origin displayed divergent post-run blood lactate concentrations (p400m[La]) and (2) if this discrepancy was based on differences in lactate exchange and removal abilities. Twenty male African (n = 12) and Caucasian (n = 8) runners, paired in terms of personal record, performed (1) an all-out 400-m run to measure p400m[La] at 3, 5 and 7 min into recovery and (2) a 1-min 25.2 km h⁻¹ running (not maximal but standardized) exercise followed by 90-min passive recovery to determine individual blood lactate recovery curves (IBLRC). IBLRCs were fitted to a bi-exponential time function: \( {\text{La(}}t )= {\text{La(}}0 )+ {{\text{A}}_1}( 1-{{\text{e}}^{ - {\gamma_ 1}t}}) + {{\text{A}}_ 2}( 1-{{\text{e}}^{ - {\gamma_ 2}t}}) \) where γ ₁ and γ ₂ denote lactate exchange ability between the previously worked muscles and blood, and overall ability for lactate removal, respectively. The quantity of lactate accumulated at the end of the 1-min exercise (Q _LaA) was also estimated. Our study showed that after the all-out 400-m run, p400m[La] was lower in African than in Caucasian runners at 3 and 5 min but not at 7 min into recovery. After the standardized exercise, γ ₁ and γ ₂ were lower (p < 0.01) and Q _LaA was higher (p < 0.05) in African than in Caucasian runners. These data suggest that for similar performance levels, ethnicity involves differences in lactate accumulation, exchange and removal.