Nocturnal leg cramps (NLCs) are often described as a symptom of sudden and involuntary muscle contraction at night, which often affects sleep quality due to pain and tight discomfort in the thigh, calf and foot. The investigator performed extracorporeal shock wave therapy (ESWT). This experiment used a randomized experiment to assess the immediate, short-term and long-term effects of extracorporeal shock wave therapy on patients with nocturnal leg cramps.

Nocturnal leg cramps (NLCs) are often described as a symptom of sudden and involuntary muscle contraction at night, which often affects sleep quality due to pain and tight discomfort in the thigh, calf and foot. The pathophysiology of nocturnal leg cramps is unclear, but it is generally considered to be associated with excitability lower motor neurons, sleep posture at night, leg muscle fatigue, nerve disability or damage (eg, Parkinson's disease), metabolic diseases (eg : hyperphosphatemia). Generally, quinine or magnesium oxide is the most commonly used pharmacological treatment. The common non-drug treatments are stretching exercise, massage or hot therapy, but there is not enough evidence to indicate which treatment is specific effective.

In a previous study, they proposed that nocturnal leg cramps may be associated with myofascial trigger points (MTrPs) of the gastrocnemius. Other studies have also proposed that extracorporeal shock wave therapy (ESWT) applying to the MTrPs of the upper trapezius muscle could improve cervicogenic headache. We will conduct a randomized parallel study to investigate the efficacy of ESWT on nocturnal leg cramps. Participants will be randomized into two groups: one is only general physical therapy (gPT) and the other one is ESWT + gPT.

The outcome measurement tools including the frequency of nocturnal leg cramps, visual analog scale (VAS), pain pressure threshold (PPT) and muscle tone in the gastrocnemius, range of motion of knee and ankle, and quality of sleep questionnaire were used to compare two groups with regard to the pain intensity, quality of sleep, and overall satisfaction in subjects with nocturnal leg cramps.

Inclusion Criteria:

1. ≥ 20 y/o patients with NLCs: (1) 4 times/week, last 2 weeks; (2) Occurred in nighttime or resting time of daytime
2. Patients with MTrPs on gastrocnemius (According to the diagnostic criteria proposed by Simons & Travell)

Exclusion Criteria:

1. (1) Taking medication for leg cramps (eg. Quinine, Magnesium oxide); (2) Other drugs that affect research and evaluation (eg. diuretics, statins, calcium channel blockers, anticonvulsants)
2. Congenital lower limb musculoskeletal diseases, Lower limb or spine surgery
3. Uncommunicated or cognitive impaired
4. Patients refused to be recruited