Relationship between lactate threshold during running and relative gastrocnemius area.

This study examined the relationship between the work rate at which blood lactate accumulation begins (lactate threshold) during running and relative gastrocnemius area in four different groups. Twenty nonathletic and 11 athletic boys (age 9-12 yr), 15 female adult runners, and 11 male nonathletic students participated in this study. The muscle composition of the leg and thigh were measured by ultrasound. The lactate threshold was assessed in terms of both the absolute work rate (ml.kg-1.min-1) and relative work rate. The relative cross-sectional area of the gastrocnemius to the plantar flexor (relative gastrocnemius area) was significantly negatively related to the absolute and relative lactate threshold in all groups. These results suggest that the relative gastrocnemius area may play an important role in determining the relative and absolute lactate threshold during running.