Relationship between lactate accumulation, LDH activity, LDH isozyme and fibre type distribution in human skeletal muscle

Abstract
Lactate concentration, total LDH [lactate dehydrogenase] activity and muscle-specific LDH isozymes were determined in pools of the 2 main types of human skeletal muscle fibers. Analyses were made from biopsy specimens obtained after intense dynamic exercise lasting approximately 30 s. Lactate concentration, total LDH activity and muscle-specific LDH activity displayed higher average values for FT (fast twitch) fibers than for ST (slow twitch) fibers. In addition, positive correlations were found both between the individual percentage of FT fibers and muscle lactate concentration and between lactate concentration and total LDH activity and muscle-specific LDH activity, respectively.