Fast to slow phenotypic changes in rabbit muscle can be induced without increases in neural activity

Immobilization of rabbit tibialis anterior (fast) muscle in a lengthened position for 5 weeks led to a fivefold increase in the number of slow oxidative fibres. Unlike the situation in other models of phenotypic change in adult muscle, the increased expression of slow phenotype was not associated with an increase in the level of electrical activation, as monitored in the stretched muscles by chronic telemetric electromyography.