Does Prophylactic Stretching Reduce the Occurrence of Exercise-Associated Muscle Cramping? A Critically Appraised Topic.

CLINICAL SCENARIO: Exercise-associated muscle cramps (EAMC) are sudden, painful, and involuntary contractions of skeletal muscles during or after physical activity. The best treatment for EAMC is gentle static stretching until abatement. Stretching is theorized to relieve EAMC by normalizing alpha motor neuron control, specifically by increasing Golgi tendon organ activity, and physically separating contractile proteins. However, it is unclear if stretching or flexibility training prevents EAMC via the same mechanisms. Despite this, many clinicians believe prophylactic stretching prevents EAMC occurrence. CLINICAL QUESTION: Do athletes who experience EAMC during athletic activities perform less prophylactic stretching or flexibility training than athletes who do not develop EAMC during competitions? SUMMARY OF KEY FINDINGS: In 3 cohort studies and 1 case-control study, greater preevent muscle flexibility, stretching, or flexibility training (ie, duration, frequency) was not predictive of who developed EAMC during competition. In one study, athletes who developed EAMC actually stretched more often and 9 times longer (9.8 [23.8] min/wk) than noncrampers (1.1 [2.5] min/wk). CLINICAL BOTTOM LINE: There is minimal evidence that the frequency or duration of prophylactic stretching or flexibility training predicts which athletes developed EAMC during competition. To more effectively prevent EAMC, clinicians should identify athletes' unique intrinsic and extrinsic risk factors and target those risk factors with interventions. STRENGTH OF RECOMMENDATION: Minimal evidence from 3 prospective cohort studies and 1 case-control study (mostly level 3 studies) that suggests prophylactic stretching or flexibility training can predict which athletes develop EAMC during athletic competitions.

Effect of Pre-dialysis Serum Sodium Measurement on Reduction of Hemodialysis Complications.

INTRODUCTION: Despite great advances in hemodialysis, complications during dialysis remain in force. Accurate assessment of dry weight is a determining factor in the prevention of hemodialysis complications. This study is designed to evaluate the effect of adjustment of ultrafiltration rate, on hemodialysis complications, based on dry weight calculation, by measuring the pre-dialysis serum sodium. METHODS: In this single-blind clinical trial 50 patients were included. The patients were randomly divided into case and control groups. First, in the intervention group, the blood sodium level was measured before dialysis. Then, the dry weight of the patients was determined, ultrafiltration was adjusted according to the dry weight, and the patients' dialysis program was performed. In the control group, dry weight was determined routinely. Blood pressure, muscle cramps, nausea, and vomiting were recorded in both groups for 3 months. RESULTS: The results showed a significant difference between the two groups in the rate of postoperative nausea and vomiting (P < .05) and muscle cramps during dialysis (P < .05). There were no significant differences between the two groups in blood pressure drop during dialysis and fatigue after hemodialysis in the first, second, and third months (P > .05). CONCLUSION: Accurate assessment of dry weight by the pre-dialysis blood sodium formula, reduces muscle cramps, nausea, and, vomiting.  DOI: 10.52547/ijkd.7170.

Vitamin K2 as a potential therapeutic candidate for the prevention of muscle cramps in hemodialysis patients: A prospective multicenter, randomized, controlled, crossover pilot trial.

OBJECTIVES: Muscle cramps occur in 33% to 78% of patients with dialysis. The etiology of muscle cramps is poorly understood, and no clear evidence-based prevention or treatment strategies exist. Improved interventions are urgently needed. The aim of this study was to investigate the effect of vitamin K2 in reducing the frequency and severity of muscle cramps in hemodialysis (HD) patients. METHODS: This multicenter, randomized, placebo-controlled, crossover clinical trial was conducted from June 2019 to May 2020. Each participant received vitamin K2 (360 µg/d) or placebo for two 4-wk phases, and then crossed to the alternative arm for two 4-wk phases after a 2-wk washout. The primary endpoint was the frequency of muscle cramps during HD. The secondary endpoints were severity and duration of muscle cramps during HD. RESULTS: A total of 523 patients with maintenance HD were screened for muscle cramps, including 41 patients with muscle cramps refractory to conventional interventions, were enrolled. Nineteen patients in the vitamin K2-initial group and 20 in the placebo-initial group completed the protocol, and were included in the final analysis. Vitamin K2 reduced the frequency, duration, and severity of muscle cramps in HD patients (all P < 0.05). The frequency, duration, and severity of muscle cramps in HD patients increased again after crossing over to the placebo. There were no serious adverse events. One patient experienced gastrointestinal discomfort when taking vitamin K2. CONCLUSIONS: This pilot trial demonstrated that vitamin K2 supplementation could decrease the frequency, duration, and severity of muscle cramps in HD patients.

An Evidence-Based Review of the Pathophysiology, Treatment, and Prevention of Exercise-Associated Muscle Cramps.

Exercise-associated muscle cramps (EAMCs) are common and frustrating for athletes and the physically active. We critically appraised the EAMC literature to provide evidence-based treatment and prevention recommendations. Although the pathophysiology of EAMCs appears controversial, recent evidence suggests that EAMCs are due to a confluence of unique intrinsic and extrinsic factors rather than a singular cause. The treatment of acute EAMCs continues to include self-applied or clinician-guided gentle static stretching until symptoms abate. Once the painful EAMCs are alleviated, the clinician can continue treatment on the sidelines by focusing on patient-specific risk factors that may have contributed to the onset of EAMCs. For EAMC prevention, clinicians should obtain a thorough medical history and then identify any unique risk factors. Individualizing EAMC prevention strategies will likely be more effective than generalized advice (eg, drink more fluids).

Prevention of leg cramps by using compression stockings or magnesium supplements in the 50-84 age group: study protocol for a randomised controlled trial.

BACKGROUND: Leg cramps are painful sensations of tightening in the muscles of the legs that commonly appear during the night and are often associated with secondary insomnia. They are common especially in older age. There is no evidence that any method of prevention of nocturnal leg cramps is both safe and effective. There are no previous trials concerning cramp prevention by using compression stockings. The objective of this study is to assess in a prospective randomised controlled trial whether leg cramps can be prevented by the daily use of knee-length compression stockings or magnesium supplements. METHODS: The study will be set in Finland, and 50-84-year-old volunteers will be recruited through Google Ads, the Finnish health library website and Finnish primary health care centres. The participants must have a minimum of two episodes of leg cramps per week for the past 4 weeks to be included in the study. The participants (n = 225) will be allocated to three equal groups: the compression stocking arm, the magnesium supplement arm and the placebo arm. The participants will go through 4 weeks of follow-up without intervention and then another 4 weeks of follow-up with the assigned intervention. The material for the study will be collected through electronic questionnaires. DISCUSSION: This protocol describes a study that compares compression stockings, magnesium supplements and placebo for the prevention of leg cramps. The results of this study can significantly improve knowledge on the methods of preventing leg cramps. TRIAL REGISTRATION: ClinicalTrials.gov NCT04694417. Registered on Jan 4, 2021.

Real-time prediction of intradialytic relative blood volume: a proof-of-concept for integrated cloud computing infrastructure.

BACKGROUND: Inadequate refilling from extravascular compartments during hemodialysis can lead to intradialytic symptoms, such as hypotension, nausea, vomiting, and cramping/myalgia. Relative blood volume (RBV) plays an important role in adapting the ultrafiltration rate which in turn has a positive effect on intradialytic symptoms. It has been clinically challenging to identify changes RBV in real time to proactively intervene and reduce potential negative consequences of volume depletion. Leveraging advanced technologies to process large volumes of dialysis and machine data in real time and developing prediction models using machine learning (ML) is critical in identifying these signals. METHOD: We conducted a proof-of-concept analysis to retrospectively assess near real-time dialysis treatment data from in-center patients in six clinics using Optical Sensing Device (OSD), during December 2018 to August 2019. The goal of this analysis was to use real-time OSD data to predict if a patient's relative blood volume (RBV) decreases at a rate of at least - 6.5 % per hour within the next 15 min during a dialysis treatment, based on 10-second windows of data in the previous 15 min. A dashboard application was constructed to demonstrate how reporting structures may be developed to alert clinicians in real time of at-risk cases. Data was derived from three sources: (1) OSDs, (2) hemodialysis machines, and (3) patient electronic health records. RESULTS: Treatment data from 616 in-center dialysis patients in the six clinics was curated into a big data store and fed into a Machine Learning (ML) model developed and deployed within the cloud. The threshold for classifying observations as positive or negative was set at 0.08. Precision for the model at this threshold was 0.33 and recall was 0.94. The area under the receiver operating curve (AUROC) for the ML model was 0.89 using test data. CONCLUSIONS: The findings from our proof-of concept analysis demonstrate the design of a cloud-based framework that can be used for making real-time predictions of events during dialysis treatments. Making real-time predictions has the potential to assist clinicians at the point of care during hemodialysis.

Non-drug therapies for the secondary prevention of lower limb muscle cramps.

BACKGROUND: 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. OBJECTIVES: To assess the effects of non-drug, non-invasive therapies for lower limb muscle cramps. SEARCH METHODS: 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. SELECTION CRITERIA: 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. DATA COLLECTION AND ANALYSIS: Two review authors independently selected trials, assessed risk of bias, and cross-checked data extraction and analyses according to standard Cochrane procedures. MAIN RESULTS: 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. AUTHORS' CONCLUSIONS: 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.

Effect of oral rehydration solution versus spring water intake during exercise in the heat on muscle cramp susceptibility of young men.

BACKGROUND: Muscle cramp is a painful, involuntary muscle contraction, and that occurs during or following exercise is referred to as exercise-associated muscle cramp (EAMC). The causes of EAMC are likely to be multifactorial, but dehydration and electrolytes deficits are considered to be factors. This study tested the hypothesis that post-exercise muscle cramp susceptibility would be increased with spring water ingestion, but reduced with oral rehydration solution (ORS) ingestion during exercise. METHODS: Ten men performed downhill running (DHR) in the heat (35-36 °C) for 40-60 min to reduce 1.5-2% of their body mass in two conditions (spring water vs ORS) in a cross-over design. The body mass was measured at 20 min and every 10 min thereafter during DHR, and 30 min post-DHR. The participants ingested either spring water or ORS for the body mass loss in each period. The two conditions were counter-balanced among the participants and separated by a week. Calf muscle cramp susceptibility was assessed by a threshold frequency (TF) of an electrical train stimulation to induce cramp before, immediately after, 30 and 65 min post-DHR. Blood samples were taken before, immediately after and 65 min after DHR to measure serum sodium, potassium, magnesium and chroride concentrations, hematocrit (Hct), hemoglobin (Hb), and serum osmolarity. Changes in these varaibles over time were compared between conditions by two-way repeated measures of analysis of variance. RESULTS: The average (±SD) baseline TF (25.6 ± 0.7 Hz) was the same between conditions. TF decreased 3.8 ± 2.7 to 4.5 ± 1.7 Hz from the baseline value immediately to 65 min post-DHR for the spring water condition, but increased 6.5 ± 4.9 to 13.6 ± 6.0 Hz in the same time period for the ORS condition (P < 0.05). Hct and Hb did not change significantly (P > 0.05) for both conditions, but osmolarity decreased (P < 0.05) only for the spring water condition. Serum sodium and chloride concentrations decreased (< 2%) at immediately post-DHR for the spring water condition only (P < 0.05). CONCLUSIONS: These results suggest that ORS intake during exercise decreased muscle cramp susceptibility. It was concluded that ingesting ORS appeared to be effective for preventing EAMC.

Postrace Dry Needling Does Not Reduce Subsequent Soreness and Cramping-A Randomized Controlled Trial.

OBJECTIVE: To identify whether a single session of postrace dry needling can decrease postrace soreness and quantity of postrace leg cramps in half-marathon and full-marathon runners. DESIGN: Single-blind, prospective, randomized, controlled trial. SETTING: Finish line of 2018 Salt Lake City Marathon & Half-Marathon. PARTICIPANTS: Runners aged 18 years or older who completed a marathon or half-marathon. INTERVENTIONS: True or sham dry needling of the bilateral vastus medialis and soleus muscles within 1 hour of race completion by 2 experienced practitioners. MAIN OUTCOME MEASURES: The primary outcome measure was numeric pain rating improvements for soreness on days 1, 2, 3, and 7 compared to immediately postrace. Secondary outcome measures included number of postrace cramps and subjective improvement of soreness. RESULTS: Sixty-two runners were included with 28 receiving true and 34 receiving sham dry needling. Objective pain scores showed an increase in pain of the soleus muscles at days 1 and 2 (P ≤ 0.003 and P ≤ 0.041, respectively) in the dry needling group. No differences were seen in postrace pain in the vastus medialis muscles (P > 0.05). No association was seen between treatment group and presence of postrace cramping at any time point (P > 0.05). Subjectively, there was a nonsignificant trend for those receiving dry needling to feel better than expected over time (P = 0.089), but no difference with cramping (P = 0.396). CONCLUSIONS: A single postrace dry needling session does not objectively improve pain scores or cramping compared to sham therapy.

Quantitative Analysis of the Acetic Acid Content in Substances Used by Athletes for the Possible Prevention and Alleviation of Exercise-Associated Muscle Cramps.

Marosek, SEH, Antharam, V, and Dowlatshahi, K. Quantitative analysis of the acetic acid content in substances used by athletes for the possible prevention and alleviation of exercise-associated muscle cramps. J Strength Cond Res 34(6): 1539-1546, 2020-Athletes regularly consume commercially available food and sports shot products, carbohydrate beverages, and water to improve their physical exertion and to possibly prevent or relieve exercise-associated muscle cramps (EAMCs)-often experienced during practice, training, or competition. Acetic acid, a component of interest within these products, has been recognized for its potential role in cramp reduction. Acetic acid is postulated to mitigate cramping by decreasing alpha motor neuron activity through oropharyngeal stimulation and inhibitory neurotransmitter production, while aiding in the role acetylcholine plays in muscle contraction and relaxation. The purpose of this research is to analytically assess the most viable sources of acetic acid from substances that athletes ingest before or when experiencing these cramps. The range of samples investigated were based on their widespread use in the athletic world: dill and sweet pickle juices, yellow mustard, sweet relish, apple cider vinegar, Hot Shot, PJ Shot, PJ Sport, E-Lyte Sport, Powerade, Gatorade, Smartwater, and Propel (with electrolytes). As hypothesized, pH and enzymatic assay or spectroscopic analyses revealed that yellow mustard, sweet relish, all pickle juices, and the pickle juice products were composed of moderate amounts of acetic acid. Based on established studies resulting in EAMC relief, acetic acid consumption, and the appropriate serving size, the yellow mustard, PJ Shot, and all pickle juices would be the most practical and palatable sources of acetic acid for strength and conditioning professionals to recommend that athletes consume for the possible prevention or alleviation of muscle cramps.

Cramping, crashing, cannulating, and clotting: a qualitative study of patients' definitions of a "bad run" on hemodialysis.

BACKGROUND: Hemodialysis sessions frequently become unstable from complications such as intradialytic hypotension and untoward symptoms. Previous patient safety initiatives promote prevention of treatment complications; yet, they have placed little specific focus on avoidable session instability. A patient-centered definition of session instability grounded in patient experiences, and an understanding of patient perceptions of causes and solutions to instability, may enable such efforts. METHODS: Twenty-five participants participated in three focus groups and/or a survey. They were purposively sampled for variation in region of residence, and sensitivity to patient well-being. Focus group recordings were analyzed using descriptive coding, in vivo coding, and thematic analysis. RESULTS: Patients define unstable sessions ("bad runs") as those in which they experience severe discomfort or unanticipated events that interfere with their ability to receive therapy. Bad runs were characterized primarily by cramping, low blood pressure ("crashing"), cannulation-related difficulties ("bad sticks"), and clotting of the dialysis circuit or vascular access. Patients believed that cramping and crashing could be explained by both patient and clinician behavior: patient fluid consumption and providers' fluid removal goals. Patients felt that the responsibility for cannulation-related problems lay with dialysis staff, and they asked for different staff or self-cannulated as solutions. Clotting was viewed as an idiosyncratic issue with one's body, and perceived solutions were clinician-driven. Patients expressed concern about "bad runs" on their ability to achieve fluid balance. CONCLUSIONS: Findings point to novel priorities for efforts to enhance hemodialysis session stability, and areas in which patients can be supported to become involved in such efforts.

Oral magnesium supplementation for leg cramps in pregnancy-An observational controlled trial.

BACKGROUND: Oral magnesium for leg cramps treatment in pregnancy is a controversial issue according to recent Cochrane systematic review. This study aims to evaluate the efficacy of Mg++ supplementation in leg cramps treatment in pregnancy. METHODS: This observational clinical trial studied 132 pregnant women with leg cramps in the first trimester of pregnancy. At baseline, 74 (56.3%) had two leg cramps episodes per week, 28 (21.1%) three episodes, 13 (9.8%) four episodes and 9 (6.8%) five or more episodes. They were randomized 1:1 to 300 mg/day of oral Mg++ citrate (n = 66) or placebo (n = 66). The primary outcome was the frequency of leg cramps episodes per week reported by pregnant women. Secondary outcomes were the ocurrence of leg cramps and oral magnesium side effects. RESULTS: 130 pregnant women completed the study and the two groups were comparable according to some sociodemographic and clinical characteristics. After 4 weeks of intervention it was observed a 28.4% (39/132) (CI 95%: 20.9-37.0) reduction of leg cramps in all participants and no difference between the two groups was found; reduction of 27.2% (18/66) (CI 95%: 17.0-39.6) in Mg++ group and 32.8% (21/66) (CI 95%: 21.6-45.7) in the placebo group. The OR of leg cramps was 1.3 (CI 95%: 0.6-2.9), p = 0.527, taking the placebo group as reference. Among pregnant women who remained with leg cramps the mean of leg cramps episodes per week showed no significance difference between the Mg++ and placebo groups; t-student test: p = 0.408. Four pregnant women showed gastrointestinal side effects; 2 in each group had nauseas and diarrhoea. CONCLUSION: Oral magnesium supplementation during pregnancy did not reduce the ocurrence and frequency of episodes of leg cramps.

Pilot testing a stretching regimen for prevention of night time nocturnal leg cramps.

Nocturnal leg cramps (NLC) are painful, involuntary muscle contractions that affect the quality of sleep. The aim of this study was to examine the feasibility and effectiveness of a stretching regimen in frail older adults aged over 75 years with NLC. The experimental group (n = 15) received an intervention, which they were instructed to perform three daily exercises to stretch the calves and hamstrings. After six weeks, frequency and pain intensity of NLC were both significantly decreased in the experimental group compared to the control group. A paired samples t-test reveals a statistically significant decrease in cramp frequency (t = 2.2, df 28, P = 0.04) and cramp intensity (t = 2.7, df 28, P = 0.01). Therefore, a six-week stretching regimen is likely to reduce the frequency and pain intensity of NLC in frail older adults aged over 75 years.

Muscle Cramping During Exercise: Causes, Solutions, and Questions Remaining.

Muscle cramp is a temporary but intense and painful involuntary contraction of skeletal muscle that can occur in many different situations. The causes of, and cures for, the cramps that occur during or soon after exercise remain uncertain, although there is evidence that some cases may be associated with disturbances of water and salt balance, while others appear to involve sustained abnormal spinal reflex activity secondary to fatigue of the affected muscles. Evidence in favour of a role for dyshydration comes largely from medical records obtained in large industrial settings, although it is supported by one large-scale intervention trial and by field trials involving small numbers of athletes. Cramp is notoriously unpredictable, making laboratory studies difficult, but experimental models involving electrical stimulation or intense voluntary contractions of small muscles held in a shortened position can induce cramp in many, although not all, individuals. These studies show that dehydration has no effect on the stimulation frequency required to initiate cramping and confirm a role for spinal pathways, but their relevance to the spontaneous cramps that occur during exercise is questionable. There is a long history of folk remedies for treatment or prevention of cramps; some may reduce the likelihood of some forms of cramping and reduce its intensity and duration, but none are consistently effective. It seems likely that there are different types of cramp that are initiated by different mechanisms; if this is the case, the search for a single strategy for prevention or treatment is unlikely to succeed.

Electrolyte beverage consumption alters electrically induced cramping threshold.

BACKGROUND: Recent investigations have questioned the role of hydration and electrolytes in cramp susceptibility and thus the efficacy of consuming electrolyte-rich carbohydrate beverages (EB) to control/prevent cramping. METHODS: Nine euhydrated, cramp-prone participants had their cramp susceptibility assessed by measuring the nerve stimulation threshold frequency at which cramping occurs (TF) before and after consumption of an EB (kCal: 120, Na: 840 mg, K: 320 mg, Mg: 5 mg) and placebo beverage (PB: kCal: 5, Na: 35 mg). Cramp intensity was assessed using a verbal pain scale and poststimulation electromyography (EMG). RESULTS: TF was greater in EB (14.86 ± 7.47 Hz) than PB (14.00 ± 5.03 Hz; P = .038) and reported pain was lower in EB (2.0 ± 0.6) than PB (2.7 ± 0.8; P = .025) while EMG was similar (P = .646). DISCUSSION: EB consumption decreased cramp susceptibility and pain but did not prevent cramping in any participants. These results suggest that electrolyte consumption independent of hydration can influence cramp susceptibility in young people.

Can L-carnitine supplementation and exercise improve muscle complications in patients with liver cirrhosis who receive branched-chain amino acid supplementation?

BACKGROUND: The aim of this study was to elucidate the efficacy of the combination of L-carnitine and exercise, reported to prevent muscle wasting, for muscle complications (function, volume, and cramping) in patients with liver cirrhosis (LC) who received branched-chain amino acid supplementation. MATERIALS AND METHODS: From December 2017 to April 2018, 18 patients with LC who had been given branched-chain amino acid granule supplementation (12.45 g/day) were enrolled (mean age 68.4±10.8 years; 10 males and eight females; Child-Pugh A : B=9 : 9). After evaluating the average number of daily steps, oral L-carnitine supplementation (1000 mg/day) and additional exercise (plus 2000 steps/day) were added for 6 months. Every 4 weeks, a pedometer, a hand dynamometer, ergometer, and bioelectrical impedance analysis were used to evaluate daily steps, muscle function and muscle volume, and muscle cramps were recorded using a numerical rating scale. RESULTS: Average steps and serum levels of total and free carnitine were increased from before treatment to the final measurement (1883.5±1211.6 vs. 3165.1±1800.0/day, 62.6±16.5 vs. 110.9±28.6 µmol/l, and 47.7±15.2 vs. 83.2±21.5 µmol/l, respectively; P<0.01), whereas there were no significant changes in the ratios of handgrip strength, leg strength, and muscle volume after 6 months [1.00±0.13 (P=0.991), 1.07±0.13 (P=0.073), and 0.992±0.036 (P=0.390), respectively]. However, the frequency of complaints of muscle cramping was reduced as compared with the start of therapy (baseline, 3 months, and 6 months: 6.3±4.8, 3.1±3.3, and 2.1±2.0, respectively) (P=0.025, Holm's method), whereas numerical rating scale did not show any significant improvement. CONCLUSION: L-Carnitine may have an important role for prevention of muscle wasting and reducing the frequency of muscle cramping.

Sodium Intake Beliefs, Information Sources, and Intended Practices of Endurance Athletes Before and During Exercise.

There is little information describing how endurance athletes perceive sodium intake in relation to training and competition. Using an online questionnaire, this study assessed the beliefs, information sources, and intended practices regarding sodium ingestion for training and competition. Endurance athletes (n = 344) from six English-speaking countries completed the questionnaire and were included for analysis. The most cited information sources were social supports (63%), self-experimentation (56%), and media (48%). Respondents generally believed (>50% on electronic visual analog scale) endurance athletes require additional sodium on a daily basis (median 67% [interquartile range: 40-81%]), benefit from increased sodium in the days preceding competition (60% [30-77%]), should replace sodium losses during training (69% [48-83%]) and competition (74% [54-87%]), and would benefit from sweat composition testing (82% [65-95%]). Respondents generally believed sodium ingestion during endurance exercise prevents exercise-associated muscle cramps (75% [60-88%]) and exercise-associated hyponatremia (74% [62-89%]). The majority (58%) planned to consciously increase sodium or total food intake (i.e., indirectly increasing sodium intake) in the days preceding competition. Most (79%) were conscious of sodium intake during competition, but only 29% could articulate a specific intake plan. A small minority (5%) reported using commercial sweat testing services, of which 75% believed it was beneficial. We conclude that endurance athletes commonly perceive sodium intake as important for their sporting activities. Many intend to consciously increase sodium intake in the days preceding and during competition, although these views appear informed mostly by nonscientific and/or non-evidence-based sources.

Considerations for ultra-endurance activities: part 2 - hydration.

It is not unusual for those participating in ultra-endurance (> 4 hr) events to develop varying degrees of either hypohydration or hyperhydration. Yet, it is important for ultra-endurance athletes to avoid the performance limiting and potentially fatal consequences of these conditions. During short periods of exercise (< 1 hr), trivial effects on the relationship between body mass change and hydration status result from body mass loss due to oxidation of endogenous fuel stores, and water supporting the intravascular volume being generated from endogenous fuel oxidation and released with glycogen oxidation. However, these effects have meaningful implications during prolonged exercise. In fact, body mass loses well over 2% may be required during some ultra-endurance activities to avoid hyperhydration. Therefore, the typical hydration guidelines to avoid more than 2% body mass loss do not apply in ultra-endurance activities and can potentially result in hyperhydration. Fortunately, achieving the balance of proper hydration during ultra-endurance activities need not be complicated and has been well demonstrated to generally be achieved by simply drinking to thirst and avoiding excessive sodium supplementation with intention of replacing all sodium losses during the exercise.

Randomised clinical trial: oral taurine supplementation versus placebo reduces muscle cramps in patients with chronic liver disease.

BACKGROUND: Painful muscle cramps occur in the majority of patients with cirrhosis impacting significantly on quality of life and sleep patterns. They are frequently unrecognised or overlooked. Current management is based on anecdotal evidence or case study reports. AIM: To investigate the effect of oral taurine supplementation on frequency, duration, and intensity of muscle cramps in patients with chronic liver disease. METHODS: Patients with chronic liver disease who experienced three or more muscle cramps/week were enrolled in a double-blinded, randomised control, crossover, taurine dose-variable study. Each participant received either taurine supplementation or placebo for 4 weeks then crossed to the alternative arm. Primary outcome data for frequency, duration, and intensity of muscle cramps was recorded by participants. Participants recorded frequency, duration, and location of muscle cramps. Biochemical parameters, including serum taurine and methionine levels, were measured at each time point. Linear mixed models were used to analyse outcomes. RESULTS: Forty-nine patients were enrolled in the study and 30 patients completed the protocol. Participants who were unable to complete the protocol were not included in the final analysis due to the absence of outcome data. The mean age of participants was 54.7 years and 70% were males. Oral taurine supplementation increased serum taurine levels (P < 0.001). There were no adverse side effects associated with taurine supplementation. Participants receiving 2 g taurine/d experienced a reduction in cramp frequency (seven cramps fewer/fortnight, P = 0.03), duration (89 minutes less/fortnight P = 0.03), and severity (1.4 units less on a Likert scale P < 0.004) compared to placebo. CONCLUSIONS: Oral supplementation with 2 g taurine/d results in a clinically significant reduction in the frequency, duration, and intensity of muscle cramps in patients with chronic liver disease. Taurine should be considered as a safe and effective intervention in the management of muscle cramps in individuals with chronic liver disease. This study was registered with the Australian New Zealand Clinical Trials Register: ACTRN12612000289819.

Metformin's impact on statin-associated muscle symptoms: An analysis of ACCORD study data and research materials from the NHLBI Biologic Specimen and Data Repository Information Coordinating Center.

Statins are widely prescribed, yet statin muscle pain limits their use, leading to increased cardiovascular risk. No validated therapy for statin muscle pain exists. The goal of the study was to assess whether metformin was associated with reduced muscle pain. A secondary analysis of data from the ACCORD trial was performed. An ACCORD sub-study assessed patients for muscle cramps and leg/calve pain while walking, typical non-severe statin muscle pain symptoms. We compared muscle pain between patients using a statin (n = 445) or both a statin and metformin (n = 869) at baseline. Overall patient characteristics were balanced between groups. Unadjusted analysis showed fewer reports of muscle cramps (35%) and leg/calve pain while walking (40%) with statins and metformin compared to statin only (muscle cramps, 42%; leg/calve pain while walking, 47%). Multivariable regression demonstrated a 22% odds reduction for muscle cramps (P = 0.049) and a 29% odds reduction for leg/calve pain while walking (P = 0.01). Metformin appears to reduce the risk of non-severe statin muscle pain and additional research is needed to confirm the findings and assess metformin's impact on statin adherence and related cardiovascular outcomes.