The study will consist of up to 7 planned groups of 8 or 9 subjects each. Subjects in each cohort will be randomized to receive either ACE-083 or placebo. ACE-083 (or placebo) will be administered locally into the right quadriceps (thigh) muscle or right tibialis anterior (lower leg) muscle. Subjects will receive a total of either one dose (on Day 1) or two doses (on Day 1 and Day 22). Each dose administered could include up to 4 injections of study drug into pre-defined locations in the muscle.