Acupuncturists in Japan often have used gold needles combined with silver needles in patients with rheumatoid arthritis to relieve severe pain and to slow the progression of joint destruction. It is not well-known how heavy metal ions which were delivered from needles during treatment act on skeletal muscles. In the present review, we describe possible mechanisms by which these metals lead to contract the skeletal muscle, followed by excitation-contraction uncoupling by acting on the L-type Ca²⁺ channel (dihydropyridine receptor/ voltage sensor) located on the transverse tubules and/or on the Ca²⁺ release channel/ryanodine receptor in the sarcoplasmic reticulum of skeletal muscle.