Functional consequences of tenotomy in hind limb muscles of the cat.

1. The chronic EMG activity and the contractile properties of normal, denervated or tenotomized cat triceps surae muscles were measured.2. Following Achilles tenotomy no measurable change in EMG activity occurred in either the soleus or medial gastrocnemius muscles.3. No change in the twitch time or tetanus-twitch ratio was seen following tenotomy in these muscles despite marked atrophy of the muscle. Measurements were made 3-10 weeks following the tenotomy procedures.4. Denervation results in some prolongation of the gastrocnemius twitch.5. The relationship between the contractile properties of a given muscle and the aggregate amount of activity imposed on that muscle by its innervation is discussed.