This analysis was done to determine which muscle group has the most skeletal muscle transcriptional reponses to wheel running activity. Seven male mice with C57BL/6 genetic background were placed individually in cages with running wheels and allowed free access to the wheels 24 hr per day. Access to running wheels began when the mice were 6 months old, and continued for 12 weeks. The morning after the night of running, the mice were euthanized and several muscle groups were snap froze in liquid nitrogen to preserve RNA. The same muscle groups were collected from three age-matched "sedentary" mice that were housed in ordinary cages that did not permit sustained running. For each muscle group, separate pools of polyadenylated RNA from the sedentary and wheel-running mice were prepared for deep sequencing of cDNA with the SOLiD 3 platform. Four muscle groups were examined (quadriceps femoris; gastrocnemius/plantaris; tibialis anterior; triceps brachii). For each muscle, RNA was pooled from 3 sedentary or 7 wheel-running mice (8 pools total).