Myotonic dystrophy is a muscular disorder characterized by muscle weakness and myotonia. Myotonia menifest as abnormally slow relaxation after strong voluntary contraction. So patients with myotonic dystrophy are difficult to perform activities of daily living. In our previous study we reported that quinine sulfate therapy not combined with muscle strengthening exercise provided therapeutic benifit to myotonia but not muscle weakness. The purpose of this study was to determine the effect of six-month home exercise program based on muscle strengthening exercise. Seven patients with myotonic dystrophy trained daily for six months at home with weights adapted to their force or without any tools and received one gram of quinine sulfate daily for six months. The changes of muscle strength and relaxation times between pretherapy and post-quinine sulfate therapy and post-six-month home exercise program combined with quinine sulfate therapy were assessed from the first dorsal interossei, elbow flexors, and knee extensors. The results were as follows: ① The improvement of the mean muscle strengh of the elbow flexors, and knee extensors was significant compared with pretherapy and post-quinine sulfate therpay. ② The improvement of the mean muscle strength of the first dorsal interossei was slight but not significant compared with pretherapy and post-quinine sulfate therapy. ③ The shortening of relaxation times of the three muscles was significant compared with pretherapy. ④ The shortening of relaxation times of the three muscles was slight but not significant compared with post-quinine sulfate therapy. In conclusion, home exercise program based on muscle strenghening exercise combined with quinine sulfate therapy showed significant improvement of the muscle strength and shortening of relaxation times for the patients with myotonic dystrophy.
