Background: Monophasic high voltage stimulation (MHVS) is widely prescribed for the treatment of inflammation associated with muscle injury. However, limited scientific evidence exists to support its purported benefits in humans. Objective: To examine the efficacy of early initiation of MHVS treatment after muscle injury. Methods: In a randomised, cross over design, 14 men performed repetitive eccentric contractions of the elbow flexor muscles followed by either MHVS or control treatment. MHVS treatments were applied five minutes and 3, 6, 24, 48, 72, 96, and 120 hours after eccentric contractions. Results: MHVS resulted in a significant reduction (p<0.05) in delayed onset muscle soreness 24 hours after eccentric exercise compared with controls. Elbow extension was significantly increased immediately after administration of MHVS compared with controls. No significant differences were observed between MHVS treatment and controls for maximal isometric strength, flexed arm angle, or arm volume. Conclusions: Early and frequent application of MHVS may provide transient relief from delayed onset muscle soreness and short term improvements in range of motion after injurious exercise. However, MHVS treatment may not enhance recovery after muscle injury because of lack of improvements in strength and active range of motion.