What is the aim of this review?
People commonly have muscle cramps at night while trying to sleep, during exercise, during pregnancy, and during haemodialysis (filtering of blood for people with severe kidney problems). Cramps can also occur at other times, and can be especially frequent and severe in children and adults with nerve diseases (for example, Charcot-Marie-Tooth disease).
There are many treatments available for leg and foot cramps. Most have not been tested in well designed clinical trials. Using untested interventions is not ideal, as people may be wasting their time or money, and may be exposing themselves to risk of harm. In this Cochrane Review, we collected and analysed all relevant studies to find out if any non-drug interventions were helpful for cramps in the legs and feet.
There is very little evidence from randomised trials to help people make decisions about non-drug treatments for leg or foot cramps. We cannot be certain if any non-drug therapy is particularly helpful, because there are not enough studies on which to base decisions, and cramps have generally not been well measured. No study tested non-drug therapies in people under age 50 years, or with neurological disease. The current evidence provides some support that combining daily calf and hamstring stretching may reduce the severity of night-time lower limb muscle cramps in people 55 years of age and older, but the effect on the frequency of cramps is not clear; the certainty of the evidence is very low.
What was studied in this review?
We were interested in studies that compared stretching, exercise, massage, relaxation, fatigue avoidance, night-time temperature control, changes in sleeping and sitting positions, and splints worn while sleeping to each other, to no treatment, or to placebo or sham (pretend) treatment. We excluded studies that examined cramps in pregnancy (as they are covered in another Cochrane Review), or invasive treatments (such as surgery or acupuncture).
We wondered if therapies could reduce how often cramps occurred, how painful they were, how long each cramp lasted, how many people experienced cramps, how well people could sleep, or join in daily activities, and if there were any harmful effects.
What are the main results of the review?
Three studies (201 participants) provided low- or very low-certainty evidence on the effectiveness of stretching to reduce lower leg cramps in people aged 50 years and older. One study received government funding; the other two did not report a funding source.
A combination of daily calf and hamstring stretching (compared to no intervention) may reduce the severity of night-time lower limb muscle cramps in people over 55 years old (1 RCT, 80 people).
Calf stretching alone (compared to sham stretching) may lead to little or no difference in how often people, aged 60 years and older, have night-time cramps in any lower limb muscle, although limitations in the study's design make it difficult to see how the results relate to clinical practice (1 RCT, 97 people).
The evidence is uncertain whether a combination of daily calf, quadriceps, and hamstring stretching (compared to no intervention) reduces the frequency and severity of leg cramps in 50- to 60-year-old women with metabolic syndrome (a group of health conditions leading to increased risk of heart diseases and related problems), as serious imitations in the study's design limited our confidence in the results (1 RCT, 24 women).
None of the people in the trials reported any side effects with treatment but we can only be moderately confident in this finding as the trials were small.
No study reported the effects of treatment on quality of sleep, quality of life, or participation in activities of daily living. No study tested non-drug treatment in people with neurological disease, during exercise, or night-time cramps in younger adults.
How up to date is this review?
We searched for studies published up to May 2020.
A combination of daily calf and hamstring stretching for six weeks may reduce the severity of night-time lower limb muscle cramps in people aged 55 years and older, but the effect on cramp frequency is uncertain. Calf stretching alone compared to sham stretching for 12 weeks may make little or no difference to the frequency of night-time lower limb muscle cramps in people aged 60 years and older. The evidence is very uncertain about the effects of a combination of daily calf, quadriceps, and hamstring stretching on the frequency and severity of leg cramps in 50- to 60-year-old women with metabolic syndrome. Overall, use of unvalidated outcome measures and inconsistent diagnostic criteria make it difficult to compare the studies and apply findings to clinical practice.
Given the prevalence and impact of lower limb muscle cramps, there is a pressing need to carefully evaluate many of the commonly recommended and emerging non-drug therapies in well-designed RCTs across all types of lower limb muscle cramps. A specific cramp outcome tool should be developed and validated for use in future research.
Lower limb muscle cramps are common and painful. They can limit exercise participation, and reduce quality of sleep, and quality of life. Many interventions are available for lower limb cramps; some are controversial or could cause harm, and often, people experience no benefit from the interventions used. This is an update of a Cochrane Review first published in 2012. We updated the review to incorporate new evidence.
To assess the effects of non-drug, non-invasive therapies for lower limb muscle cramps.
In August 2018 and May 2020, we searched the Cochrane Neuromuscular Specialised Register, CENTRAL, MEDLINE, Embase, the World Health Organization International Clinical Trials Registry Platform, ClinicalTrials.gov, and reference lists of included studies. We imposed no restrictions by language or publication date.
We included all randomised controlled trials (RCTs) of non-drug, non-invasive interventions tested over at least four weeks, for lower limb muscle cramps in any group of people, except pregnant women. The primary outcome was cramp frequency. Secondary outcomes were cramp pain severity, cramp duration, health-related quality of life, quality of sleep, participation in activities of daily living, proportion of participants reporting lower limb muscle cramps, and adverse events.
Two review authors independently selected trials, assessed risk of bias, and cross-checked data extraction and analyses according to standard Cochrane procedures.
We included three trials, with 201 participants, all 50 years of age and older; none had neurological disease. All trials evaluated a form of stretching for lower limb muscle cramps.
A combination of daily calf and hamstring stretching for six weeks may reduce the severity of night-time lower limb muscle cramps (measured on a 10 cm visual analogue scale (VAS) where 0 = no pain and 10 cm = worst pain imaginable) in people aged 55 years and older, compared to no intervention (mean difference (MD) -1.30, 95% confidence interval (CI) -1.74 to -0.86; 1 RCT, 80 participants; low-certainty evidence). The certainty of evidence was very low for cramp frequency (change in number of cramps per night from week zero to week six) comparing the stretching group and the no intervention group (MD −1.2, 95% CI −1.8 to −0.6; 80 participants; very low-certainty evidence).
Calf stretching alone for 12 weeks may make little to no difference to the frequency of night-time lower limb muscle cramps in people aged 60 years and older (stretching group median number of cramps in the last four weeks (Md) 4, interquartile range (IQR) 8; N = 48; sham stretching group Md 3, IQR 7.63; N = 46) (U = 973.5, z = -0.995, P = 0.32, r = 0.10; 1 RCT, 94 participants; low-certainty evidence). This trial did not report cramp severity.
The evidence is very uncertain about the effects of a combination of daily calf, quadriceps, and hamstring stretching on the frequency and severity of leg cramps in 50- to 60-year-old women with metabolic syndrome (N = 24). It was not possible to fully analyse the frequency data and the scale used to measure cramp severity is not validated.
No study reported health-related quality of life, quality of sleep, or participation in activities of daily living. No participant in these three studies reported adverse events. The evidence for adverse events was of moderate certainty as the studies were too small to detect uncommon events.
In two of the three studies, outcomes were at risk of recall bias, and tools used to measure outcomes were not validated. Due to limitations in study designs that led to risks of bias, and imprecise findings with wide CIs, we cannot be certain that findings of future studies will be similar to those presented in this review.