Aetiology of skeletal muscle 'cramps' during exercise: a novel hypothesis

A scoping review on muscle cramps and spasms in upper motor neuron disorder-two sides of the same coin?

Background

Muscle cramps are typically regarded as benign muscle overactivity in healthy individuals, whereas spasms are linked to spasticity resulting from central motor lesions. However, their striking similarities made us hypothesize that cramping is an under-recognized and potentially misidentified aspect of spasticity.

Methods

A systematic search on spasms and cramps in patients with Upper Motor Neuron Disorder (spinal cord injury, cerebral palsy, traumatic brain injury, and stroke) was carried out in Embase/Medline, aiming to describe the definitions, characteristics, and measures of spasms and cramps that are used in the scientific literature.

Results

The search identified 4,202 studies, of which 253 were reviewed: 217 studies documented only muscle spasms, 7 studies reported only cramps, and 29 encompassed both. Most studies (n = 216) lacked explicit definitions for either term. One-half omitted any description and when present, the clinical resemblance was significant. Various methods quantified cramp/spasm frequency, with self-reports being the most common approach.

Conclusion

Muscle cramps and spasms probably represent related symptoms with a shared pathophysiological component. When considering future treatment strategies, it is important to recognize that part of the patient's spasms may be attributed to cramps.

Wilderness Medical Society Clinical Practice Guidelines for the Prevention and Treatment of Heat Illness: 2024 Update

The Wilderness Medical Society (WMS) convened an expert panel in 2011 to develop a set of evidence-based guidelines for the recognition, prevention, and treatment of heat illness. The current panel retained 5 original members and welcomed 2 new members, all of whom collaborated remotely to provide an updated review of the classifications, pathophysiology, evidence-based guidelines for planning and preventive measures, and recommendations for field- and hospital-based therapeutic management of heat illness. These recommendations are graded based on the quality of supporting evidence and the balance between the benefits and risks or burdens for each modality. This is an updated version of the WMS clinical practice guidelines for the prevention and treatment of heat illness published in Wilderness & Environmental Medicine. 2019;30(4):S33-S46.

Practicing Outside the Lines: Using Acupuncture in the Athletic Training Room and on the Field

Acupuncture can be used to treat athletes in an outpatient clinic setting, athletic training room, or even on a football field sideline. This article details 3 scenarios, in 3 illustrative cases, in which acupuncture was used for sports medicine in more unconventional settings. The author describes each case and shares his observations about them. First, acupuncture was used on a high-school football field sideline to help alleviate acute calf cramping in a player. Second, acupuncture was used in a division 2 college athletic training room to treat a player with subacute thoracic pain that was not improving with the usual treatments provided by the athletic trainers. Third, acupuncture was used to treat hamstring strain and tightness in a professional National Football League player to enhance his performance. These situations demonstrate the versatility of acupuncture in the realm of sports medicine. Acupuncture is an added-value service for athletes, and acupuncture providers should not be afraid to promote it in this population that is always looking for a competitive advantage.

Males, Older Age, Increased Training, Chronic Diseases, Allergies, and History of Injury Are Independent Risk Factors Associated With a History of Exercise-Associated Muscle Cramping in Distance Runners in 76 654 Race Entrants - SAFER XXIX

OBJECTIVE

To determine independent risk factors associated with a history of exercise-associated muscle cramps (hEAMCs) in distance runner race entrants in a community-based mass participation event.

DESIGN

Cross-sectional study.

SETTING

2012 to 2015, Two Oceans marathon races (21.1 and 56 km), South Africa.

PARTICIPANTS

Seventy six thousand six hundred fifty-four consenting race entrants.

ASSESSMENT OF RISK FACTORS

Entrants completed an online prerace medical screening questionnaire as part of the entry process. In a multiple model, sex, age, training variables, history of chronic disease, allergies, and running injuries were included as potential factors associated with hEAMC in 21.1 and 56 km entrants.

MAIN OUTCOME MEASURES

Prevalence (%) and prevalence ratios (PRs, 95% confidence intervals) are reported.

RESULTS

Men ( P < 0.0001) and older age (>40 years, P < 0.0001) were significantly associated with hEAMC. Therefore, the model was adjusted for sex and age group and run separately for 21.1- and 56-km entrants. Specific independent risk factors associated with hEAMC in 21.1- and 56-km entrants were: a history of chronic diseases (21.1 km: PR = 1.9; 56 km: PR = 1.6; P < 0.0001), running injury in the last 12 months (21.1 km: PR = 1.7; 56 km: PR = 1.4; P < 0.0001), history of allergies (21.1 km: PR = 1.4; 56 km: PR = 1.2; P < 0.0001), and various training variables (PR = 1.0-1.1).

CONCLUSION

In 21.1- and 56-km race entrants, independent risk factors associated with hEAMC were men, older age, longer race distances, training variables, chronic diseases, history of allergies, and history of a running injury in the past 12 months.

Prevalence, Clinical Characteristics, and Self-Reported Treatment of Exercise-Associated Muscle Cramping Differ Between 21.1- and 56-Km Running Race Entrants-SAFER XXII

OBJECTIVE

To determine whether the lifetime prevalence and clinical characteristics of exercise-associated muscle cramping (EAMC) differ between runners entering a 21.1- versus 56-km road race.

DESIGN

Cross-sectional study.

SETTING

The 2012 to 2015 Two Oceans Marathon races (21.1 and 56 km), South Africa.

PARTICIPANTS

Participants were consenting race entrants (21.1 km = 44 458; 56 km = 26 962) who completed an online prerace medical screening questionnaire.

INDEPENDENT VARIABLE

A history of EAMC.

MAIN OUTCOME MEASURES

The main outcome variables were lifetime prevalence (%) and clinical characteristics (muscle groups affected, timing of occurrence, severity, frequency of serious EAMC, and self-reported treatment) of a history of EAMC. Differences between 56- and 21.1-km race entrants were explored (relative risk [RR]).

RESULTS

The lifetime prevalence of EAMC was 12.8%, which was higher in 56- (20.0%; 95% CI 19.5-20.6) versus 21.1-km race entrants (8.5%; 8.2-8.8) ( P = 0.0001). In all entrants, the fourth quarter was the most common onset (46.4%), calf muscles were the most commonly affected (53.1%), and most EAMCs were of mild-to-moderate severity (95%). In 56- versus 21.1-km entrants, hamstring (RR = 1.7; 1.5-1.9) and quadriceps muscle groups (RR = 1.5; 1.3-1.7) were more frequently affected ( P = 0.0001), the onset of EAMC during racing was less common in the first quarter (RR = 0.3; 0.2-0.4) ( P = 0.0001), and serious EAMC was more frequent (RR = 1.6; 1.4-1.9) ( P = 0.0001).

CONCLUSIONS

In 56- versus 21.1-km runners, a history of EAMC is 2 times more frequent and muscle groups affected, onset in a race, and severity of EAMC differed. The lifetime prevalence was lower than previously reported in other events. Risk factors associated with EAMC may differ between entrants for different race distances.

Chronic prescription medication use in endurance runners: a cross-sectional study in 76,654 race entrants - SAFER XV

OBJECTIVE

To determine the prevalence of chronic prescription medication (CPM) use in distant runners (by age and sex) and to compare CPM use in 21.1 km vs. 56 km race entrants.

METHODS

A cross-sectional study of 76,654 race entrants who completed a pre-race medical screening questionnaire during race registration, which included questions on the use of CPM and CPM use in eight main categories of CPM. Prevalence (%, 95%CIs) and prevalence ratios (PR) are reported.

RESULTS

The prevalence of any CPM use was 12.5% (12.2-12.8). CPM use was higher in older age categories vs. the youngest age category (31-40 yrs vs. ≤30 yrs: PR = 1.4; 41-50 yrs vs. ≤30 yrs: PR = 2.1; >50 yrs vs. ≤30 yrs: PR = 3.4) (p < 0.0001) and females vs. males (PR = 1.1; p < 0.0001). The use of any CPM was significantly higher in 21.1 km vs. 56 km race entrants (PR = 1.2; p < 0.0001). Prevalence of CPM use in main categories was: blood pressure lowering medication (3.7%), cholesterol lowering medication (3.6%), asthma medication (3.1%), and medication to treat anxiety/depression (2.6%). The pattern of CPM in the main categories differed between 21.1 km and 56 km race entrants.

CONCLUSIONS

One in eight race entrants use CPM, with a higher prevalence of use among older race entrants, female vs. males, and 21.1 km vs. 56 km race entrants. Frequent CPMs used are blood pressure lowering medication, cholesterol lowering medication, asthma medication, and medication to treat anxiety/depression. The use of CPM medications may increase the risk of medical complications during exercise, and these data help identify subgroups of entrants that may be at higher risk for race medical encounters.

Hamstring Muscle Cramp Visualized on Bone Single-Photon Emission Computed Tomography/Computed Tomography Hybrid Imaging

ABSTRACT

It is well recognized that bone-seeking radiotracers localize in muscles sustaining an injury from various causes (e.g., strenuous physical activity, trauma, hereditary myopathies, inflammatory myositides, medications, electrical burns, etc.). This report presents the case of an active 50-yr-old man (body mass index = 29) that was recently referred to our nuclear medicine department for bone scintigraphy, for the skeletal staging of a newly diagnosed prostate adenocarcinoma. The scan findings were unremarkable for its oncological indication but revealed extraosseous radiotracer absorption in the medial region of the hamstrings bilaterally. Hybrid scintitomography (single-photon emission computed tomography) with computed tomography indicated that this uptake involved the semitendinosus muscle. On a more meticulous repeat history questioning, he recalled experiencing muscle cramps on both posterior thighs 5 days earlier, during intense work-related physical activity (plumbing) under warm environmental conditions. The combination of strenuous exercise with likely dehydration contributed to bilateral self-limiting heat cramps of the hamstrings, leading to an inconsequential localized minor rhabdomyolysis that was discovered coincidentally a few days later during a bone scan. Although extraskeletal absorption of bone-seeking radiotracers in muscles is widely documented as a result of exertion or injury, this is the first report of radiotracer absorption induced by cramping.

Trail running injury risk factors: a living systematic review

OBJECTIVE

To review and frequently update the available evidence on injury risk factors and epidemiology of injury in trail running.

DESIGN

Living systematic review. Updated searches will be done every 6 months for a minimum period of 5 years.

DATA SOURCES

Eight electronic databases were searched from inception to 18 March 2021.

ELIGIBILITY CRITERIA

Studies that investigated injury risk factors and/or reported the epidemiology of injury in trail running.

RESULTS

Nineteen eligible studies were included, of which 10 studies investigated injury risk factors among 2 785 participants. Significant intrinsic factors associated with injury are: more running experience, level A runner and higher total propensity to sports accident questionnaire (PAD-22) score. Previous history of cramping and postrace biomarkers of muscle damage is associated with cramping. Younger age and low skin phototypes are associated with sunburn. Significant extrinsic factors associated with injury are neglecting warm-up, no specialised running plan, training on asphalt, double training sessions per day and physical labour occupations. A slower race finishing time is associated with cramping, while more than 3 hours of training per day, shade as the primary mode of sun protection and being single are associated with sunburn. An injury incidence range 0.7-61.2 injuries/1000 hours of running and prevalence range 1.3% to 90% were reported. The lower limb was the most reported region of injury, specifically involving blisters of the foot/toe.

CONCLUSION

Limited studies investigated injury risk factors in trail running. Our review found eight intrinsic and nine extrinsic injury risk factors. This review highlighted areas for future research that may aid in designing injury risk management strategies for safer trail running participation.PROSPERO registration numberCRD42021240832.

Programmed vs. Thirst-Driven Drinking during Prolonged Cycling in a Warm Environment

We compared the effect of programmed (PFI) and thirst-driven (TDFI) fluid intake on prolonged cycling performance and exercise associated muscle cramps (EAMC). Eight male endurance athletes (26 ± 6 years) completed two trials consisting of 5 h of cycling at 61% V˙O2peak followed by a 20 km time-trial (TT) in a randomized crossover sequence at 30 °C, 35% relative humidity. EAMC was assessed after the TT with maximal voluntary isometric contractions of the shortened right plantar flexors. Water intake was either programmed to limit body mass loss to 1% (PFI) or consumed based on perceived thirst (TDFI). Body mass loss reached 1.5 ± 1.0% for PFI and 2.5 ± 0.9% for TDFI (p = 0.10). Power output during the 20 km TT was higher (p < 0.05) for PFI (278 ± 41 W) than TDFI (263 ± 39 W), but the total performance time, including the breaks to urinate, was similar (p = 0.48) between conditions. The prevalence of EAMC of the plantar flexors was similar between the drinking conditions. Cyclists competing in the heat for over 5 h may benefit from PFI aiming to limit body mass loss to <2% when a high intensity effort is required in the later phase of the race and when time lost for urination is not a consideration.

[Medical emergencies during running events]

Hintergrund

Die Anzahl an kurz- und langstreckigen Laufveranstaltungen in Deutschland nimmt zu. Laufen als Breitensport wird von einer Vielzahl an Personen unterschiedlicher Altersklassen, Risikogruppen und Professionalisierungsgrade betrieben, woraus ein breites Spektrum medizinischer Notfälle resultiert.

Ziel der Arbeit

Der vorliegende Beitrag erläutert die Inzidenz, Pathophysiologie und Therapie relevanter Notfallbilder bei Laufveranstaltungen. Ziel ist die Optimierung der Arbeitsabläufe des Rettungsdienstpersonals.

Material und Methoden

Es erfolgte eine Literaturrecherche in PubMed.

Ergebnisse

Anstrengungsassoziierte Muskelkrämpfe, gastrointestinale Symptome, Kollaps, Kompartmentsyndrom und Tendinopathien sind häufige Erscheinungsbilder und resultieren meist aus akuter oder chronischer Überanstrengung. Der Kreislaufstillstand bzw. plötzliche Herztod ist ein seltenes Ereignis bei Laufveranstaltungen. Bewusstseinsstörungen und generalisierte Krampfanfälle sind schwerwiegende Komplikationen. Disseminierte intravasale Koagulopathie, belastungsinduzierte Hyponatriämie, Hitzschlag, Rhabdomyolyse und thromboembolische Ereignisse sind mit hoher Morbidität und Mortalität verbunden. Substanzen zur Erhöhung der Schmerzschwelle und leistungssteigernde Substanzen sind unter Läufern stark verbreitet und gehen mit einer hohen Rate an Nebenwirkungen einher.

Diskussion

Unspezifische Symptome wie Erbrechen, Fieber, Kollaps, Muskelschmerzen, Übelkeit, und Schwäche sind die führenden Symptome bei Laufveranstaltungen. Eine sorgfältige Anamnese ist wegweisend für eine zielgerichtete klinische Therapie. Präklinisch steht eine Symptomkontrolle im Mittelpunkt. Das Flüssigkeitsmanagement stellt eine besondere Herausforderung dar.

Exercise-related fatigue affects joint-driven resistance: comparison of flexor and extensor

[Purpose] Muscle fatigue can affect the inherent properties of muscles. It is important to know how muscle stiffness changes with muscle fatigue and the different effects of the initial and terminal stages of exercise. Therefore, we aimed to examine the effects of bicep and tricep contraction tasks that lead to fatigue on joint-driven resistance of the elbow joint. [Participants and Methods] Twenty-five healthy men were included. Joint-driven resistance of the elbow joint was measured before and after the muscle contraction task. The slope of the regression line of the angle torque at the time of passive movement was calculated as an elastic coefficient and the entire movable range, proximal range, and distal range were compared. [Results] Owing to the muscular contraction of the biceps and triceps, the elastic coefficient increased in the elbow joint during both flexion and extension. The rate of change in the elastic coefficient was lower during the tricep contraction task than during the bicep contraction task. For both tasks, the change in the elastic coefficient varied depending on the range of exercise. [Conclusion] Resistance exercise increased the driven resistance of the joint during passive movement, and this effect was greater during terminal exercises.

Fragmentary Hypnic Myoclonus and Other Isolated Motor Phenomena of Sleep

Excessive fragmentary hypnic myoclonus, hypnic jerks, hypnagogic foot tremor, alternating leg muscle activation, and sleep-related cramps are less known sleep-related motor disorders (SRMDs). These manifestations are frequently missed or misinterpreted polygraphic findings that can be frequently confused with the more frequent SRMDs. These symptoms can present as isolated motor symptoms but can be also the cause of otherwise cryptogenic insomnias and somnolence. Expanding the knowledge on these isolated symptoms and defining their polygraphic and clinical features are essential for their identification. However, clear cut-offs to discern between the isolated phenomenon and the disorder are still to be found.

Exercise under heat stress: thermoregulation, hydration, performance implications, and mitigation strategies

A rise in body core temperature and loss of body water via sweating are natural consequences of prolonged exercise in the heat. This review provides a comprehensive and integrative overview of how the human body responds to exercise under heat stress and the countermeasures that can be adopted to enhance aerobic performance under such environmental conditions. The fundamental concepts and physiological processes associated with thermoregulation and fluid balance are initially described, followed by a summary of methods to determine thermal strain and hydration status. An outline is provided on how exercise-heat stress disrupts these homeostatic processes, leading to hyperthermia, hypohydration, sodium disturbances, and in some cases exertional heat illness. The impact of heat stress on human performance is also examined, including the underlying physiological mechanisms that mediate the impairment of exercise performance. Similarly, the influence of hydration status on performance in the heat and how systemic and peripheral hemodynamic adjustments contribute to fatigue development is elucidated. This review also discusses strategies to mitigate the effects of hyperthermia and hypohydration on exercise performance in the heat by examining the benefits of heat acclimation, cooling strategies, and hyperhydration. Finally, contemporary controversies are summarized and future research directions are provided.

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.

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.

Exercise-Associated Muscle Cramps in the Tennis Player

PURPOSE OF REVIEW

Better define the proposed etiologies, risk factors, and treatment plans for exercise-associated muscle cramps in the tennis player.

RECENT FINDINGS

While no one theory has been able to fully explain the etiology behind exercise-associated muscle cramping, further classification of acute localized cramping and systemic or recurrent cramping may help guide future treatment and prevention strategies. Neuromuscular fatigue more than electrolyte deficit or dehydration is believed to play a large role in development of exercise-associated muscle cramps. Despite inconclusive evidence at this time, electrolyte deficit may play more of a role in the development of recurrent or systemic muscle cramping in the tennis athlete. More research is needed to better define its conclusive etiology.

Muscle Cramping in the Marathon: Dehydration and Electrolyte Depletion vs. Muscle Damage

Martínez-Navarro, I, Montoya-Vieco, A, Collado, E, Hernando, B, Panizo, N, and Hernando, C. Muscle Cramping in the marathon: Dehydration and electrolyte depletion vs. muscle damage. J Strength Cond Res XX(X): 000-000, 2020-Our aim was to compare dehydration variables, serum electrolytes, and muscle damage serum markers between runners who suffered exercise-associated muscle cramps (EAMC) and runners who did not suffer EAMC in a road marathon. We were also interested in analyzing race pacing and training background. Nighty-eight marathoners took part in the study. Subjects were subjected to a cardiopulmonary exercise test. Before and after the race, blood and urine samples were collected and body mass (BM) was measured. Immediately after the race EAMC were diagnosed. Eighty-eight runners finished the marathon, and 20 of them developed EAMC (24%) during or immediately after the race. Body mass change, post-race urine specific gravity, and serum sodium and potassium concentrations were not different between crampers and noncrampers. Conversely, runners who suffered EAMC exhibited significantly greater post-race creatine kinase (464.17 ± 220.47 vs. 383.04 ± 253.41 UI/L, p = 0.034) and lactate dehydrogenase (LDH) (362.27 ± 72.10 vs. 307.87 ± 52.42 UI/L, p = 0.002). Twenty-four hours post-race also values of both biomarkers were higher among crampers (CK: 2,438.59 ± 2,625.24 vs. 1,166.66 ± 910.71 UI/L, p = 0.014; LDH: 277.05 ± 89.74 vs. 227.07 ± 37.15 UI/L, p = 0.021). The difference in the percentage of runners who included strength conditioning in their race training approached statistical significance (EAMC: 25%, non-EAMC: 47.6%; p = 0.074). Eventually, relative speed between crampers and noncrampers only differed from the 25th km onward (p < 0.05). Therefore, runners who suffered EAMC did not exhibit a greater degree of dehydration and electrolyte depletion after the marathon but displayed significantly higher concentrations of muscle damage biomarkers.

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.

Muscle cramps: A comparison of the two-leading hypothesis

Exercise-Associated Muscle Cramps (EAMC) are a common painful condition of muscle spasms. Despite scientists tried to understand the physiological mechanism that underlies these common phenomena, the etiology is still unclear. From 1900 to nowadays, the scientific world retracted several times the original hypothesis of heat cramps. However, recent literature seems to focus on two potential mechanisms: the dehydration or electrolyte depletion mechanism, and the neuromuscular mechanism. The aim of this review is to examine the recent literature, in terms of physiological mechanisms of EAMC. A comprehensive search was conducted on PubMed and Google Scholar. The following terminology was applied: muscle cramps, neuromuscular hypothesis (or thesis), dehydration hypothesis, Exercise-Associated muscle cramps, nocturnal cramps, muscle spasm, muscle fatigue. From the initial literature of 424 manuscripts, sixty-nine manuscripts were included, analyzed, compared and summarized. Literature analysis indicates that neuromuscular hypothesis may prevails over the initial hypothesis of the dehydration as the trigger event of muscle cramps. New evidence suggests that the action potentials during a muscle cramp are generated in the motoneuron soma, likely accompanied by an imbalance between the rising excitatory drive from the muscle spindles (Ia) and the decreasing inhibitory drive from the Golgi tendon organs. In conclusion, from the latest investigations there seem to be a spinal involvement rather than a peripheral excitation of the motoneurons.

Underlying Chronic Disease, Medication Use, History of Running Injuries and Being a More Experienced Runner Are Independent Factors Associated With Exercise-Associated Muscle Cramping: A Cross-Sectional Study in 15778 Distance Runners

BACKGROUND

Exercise-associated muscle cramping (EAMC) is a significant medical complication in distance runners, yet factors associated with EAMC are poorly documented.

OBJECTIVE

To document risk factors associated with EAMC in runners.

DESIGN

Cross-sectional study.

SETTING

Two ocean races (21.1 km, and 56 km).

PARTICIPANTS

Fifteen thousand seven hundred seventy-eight race entrants.

METHODS

Participants completed a prerace medical history screening tool including: training, cardiovascular disease (CVD), risk factors for, and symptoms of CVD, history of diseases affecting major organ systems, cancer, allergies, medication use, and running injury. Runners were grouped as having a history of EAMC (hEAMC group = 2997) and a control group (Control = 12 781).

RESULTS

Independent factors associated with a higher prevalence ratio (PR) of hEAMC were any risk factor for CVD (PR = 1.16; P = 0.0002), symptoms of CVD (PR = 2.38; P < 0.0001), respiratory disease (PR = 1.33; P < 0.0001), gastrointestinal disease (PR = 1.86; P < 0.0001), nervous system or psychiatric disease (PR = 1.51; P < 0.0001), kidney or bladder disease, (PR = 1.60; P < 0.0001), haematological or immune disease (PR = 1.54; P = 0.0048), cancer (PR = 1.34; P = 0.0031), allergies (PR = 1.37; P < 0.0001), regular medication use (PR = 1.80; P < 0.0001), statin use (PR = 1.26; P = 0.0127), medication use during racing (PR = 1.88; P < 0.0001), running injury (PR = 1.66; P < 0.0001), muscle injury (PR = 1.82; P < 0.0001), tendon injury (PR = 1.62; P < 0.0001), and runners in the experienced category (PR = 1.22; P < 0.0001).

CONCLUSION

Novel risk factors associated with EAMC in distance runners were underlying chronic disease, medication use, a history of running injuries, and experienced runners. These factors must be identified as possible associations, and therefore be considered in the diagnosis and treatment of EAMC.

Exercise-Associated Muscle Cramp-Doubts About the Cause

Introduction:

Exercise-associated muscle cramp (EAMC) is one of the most common conditions that occur during or immediately after the exercise, with questionable etiology.

Aim:

Aim of article was to present doubts about the cause of EAMC, whether it is primarily a neurological condition or it is water and salt imbalance.

Results:

Strongest evidence supports the neuromuscular aetiology with the focus on the muscle fatigue. Muscle overload and fatigue affects the balance between the excitatory drive from muscle spindles and the inhibitory drive from the Golgi tendon organs (GTO). This results in a localized muscle cramp. Since the dehydration and electrolyte depletion are systemic abnormalities, it is not clear how these changes would result in local symptoms such as cramping of the working muscle groups.

Conclusion:

“Triad” of causes might be behind the etiology of EAMC, although the “altered neuromuscular control” theory with the “dehydration” theory is the most cogent descriptive model that explains the origin of EAMC. Treatment and prevention strategies for EAMC include: electrical cramp induction, kinesio taping and compression garments, massage therapy, electrolyte supplementation and hydration, corrective exercise, stretching, quinine, pickle juice, hyperventilation strategies.

Prophylactic stretching does not reduce cramp susceptibility

INTRODUCTION

Some clinicians advocate stretching to prevent muscle cramps. It is unknown whether static or proprioceptive neuromuscular facilitation (PNF) stretching increases cramp threshold frequency (TF_c ), a quantitative measure of cramp susceptibility.

METHODS

Fifteen individuals completed this randomized, counterbalanced, cross-over study. We measured passive hallux range of motion (ROM) and then performed 3 minutes of either static stretching, PNF stretching (hold-relax-with agonist contraction), or no stretching. ROM was reassessed and TF_c was measured.

RESULTS

PNF stretching increased hallux extension (pre-PNF 81 ± 11°, post-PNF 90 ± 10°; P < 0.05) but not hallux flexion (pre-PNF 40 ± 7°, post-PNF 40 ± 7°; P > 0.05). Static stretching increased hallux extension (pre-static 80 ± 11°, post-static 88 ± 9°; P < 0.05) but not hallux flexion (pre-static 38 ± 9°, post-static 39 ± 8°; P > 0.05). No ROM changes occurred with no stretching (P > 0.05). TF_c was unaffected by stretching (no stretching 18 ± 7 Hz, PNF 16 ± 4 Hz, static 16 ± 5 Hz; P = 0.37).

DISCUSSION

Static and PNF stretching increased hallux extension, but neither increased TF_c . Acute stretching may not prevent muscle cramping. Muscle Nerve 57: 473-477, 2018.

Acute Passive Static Stretching and Cramp Threshold Frequency

CONTEXT

  Exercise-associated muscle cramps are a common clinical problem for athletes.

OBJECTIVE

  To determine whether acute passive static stretching altered cramp threshold frequency (CTF) of electrically induced muscle cramps.

DESIGN

  Crossover study.

SETTING

  Laboratory.

PATIENTS OR OTHER PARTICIPANTS

  Seventeen healthy college-aged individuals.

INTERVENTION(S)

  Stretching or no stretching.

MAIN OUTCOME MEASURE(S)

  The independent variable was the static stretch versus the no-stretch condition, and the dependent variable was the CTF.

RESULTS

  The CTF increased in both the control (pretest: 18.12 ± 6.46 Hz, posttest: 19.65 ± 7.25 Hz; P = .033) and stretching (pretest: 18.94 ± 5.96 Hz, posttest: 20.47 ± 7.12 Hz; P = .049) groups. No difference between the groups was found (t₁₅ = 0.035, P = .97).

CONCLUSIONS

  Acute passive static stretching did not seem to increase the CTF.

Effects of TRPV1 and TRPA1 activators on the cramp threshold frequency: a randomized, double-blind placebo-controlled trial

PURPOSE

Previous data indicate that a strong sensory input from orally administered TRPV1 and TRPA1 activators alleviates muscle cramps in foot muscles by reducing the α-motor neuron hyperexcitability. We investigated if TRP activators increase the cramp threshold frequency of the medial gastrocnemius.

METHODS

We randomly assigned 22 healthy male participants to an intervention (IG) and a control group (CG). While participants of the IG ingested a mixture of TRPV1 and TRPA1 activators, the CG received a placebo. We tested the cramp threshold frequency (CTF), the cramp intensity (EMG activity), and the perceived pain of electrically induced muscle cramps before (pre), and 15 min, 4, 8, and 24 h after either treatment. We further measured the maximal isometric force of knee extensors at pre, 4, and 24 h to assess potential side-effects on the force output.

RESULTS

When we included all measurement time points, no group-by-time interaction was observed for the CTF. However, when only pre and 15 min values were incorporated, a significant interaction, with a slightly greater CTF increase in IG (3.1 ± 1.5) compared to the CG (2.0 ± 1.5), was observed. No significant group by time interaction was found for the cramp intensity, the perceived pain, and the maximal isometric force.

CONCLUSION

Our data indicate that orally administered TRPV1 and TRPA1 activators exert a small short-term effect on the CTF, but not on the other parameters tested. Future studies need to investigate whether such small CTF increments are sufficient to prevent exercise-associated muscle cramps.

Muscle cramp susceptibility increases following a volitionally induced muscle cramp

INTRODUCTION

Muscle cramping may increase peripheral nervous system excitability. It is unknown if, and how long, cramp susceptibility is affected by previous cramping. We tested whether volitionally induced muscle cramps (VIMCs) lowered cramp threshold frequency (TF_c ) and how long TF_c was affected post-VIMC.

METHODS

Fifteen cramp-prone participants volitionally induced a flexor hallucis brevis (FHB) cramp on 4 separate days. FHB TF_c was measured before VIMC (i.e., baseline) and 5, 30, and 60 min post-VIMC. VIMC electromyography (EMG) amplitude, VIMC duration, and perceived VIMC intensity were measured to ensure consistency of VIMC between days.

RESULTS

VIMC EMG amplitude, duration, and perceived intensity were similar between days (P > 0.05). VIMC lowered TF_c ; baseline TF_c (18 ± 6 Hz) was higher than 5-min (14 ± 6 Hz), 30-min (14 ± 5 Hz), and 60-min TF_c (14 ± 5 Hz; P < 0.05).

DISCUSSION

Acute VIMCs increase cramp susceptibility. Clinicians should apply treatments for at least 60 min postcramp to decrease the probability of cramp recurrence. Muscle Nerve 56: E95-E99, 2017.

Cramp Training Induces a Long-Lasting Increase of the Cramp Threshold Frequency in Healthy Subjects

OBJECTIVE

A low cramp threshold frequency (CTF) is associated with an increased cramp susceptibility. Recent data indicate that the CTF can be substantially increased by a cramp training consisting of electrically induced muscle cramps (EIMCs). This study investigated if four cramp training sessions induce sustained effects on the CTF.

METHODS

In ten healthy male subjects, EIMCs were induced in the gastrocnemius medialis of one leg (intervention leg, IL) twice a week, while the opposite leg served as control leg (CL). The stimulation protocol consisted of three sets of six bipolar rectangular wave pulsed currents (5 sec on, 10 sec off) at 30 Hz above the individual CTF.

RESULTS

After four cramp training sessions (2 weeks) the CTF differed (p < 0.001) from pre-values in the IL (pre: 19.2 ± 1.4 Hz post 29.8 ± 8.0 Hz) but not in the CL (pre: 18.2 ± 1.5 Hz post 19.6 ± 2.8 Hz; p > 0.05). Thereafter, the CTF remained elevated in the IL for 22 days (22 days post: 22.2 ± 3.2 Hz; p < 0.05) when compared to pre and was significantly (p < 0.05) higher than that of the CL 5, 10, and 14 days after the intervention.

CONCLUSION

The applied cramp training induced a long-term CTF increase of 14 days.

Are Electrically Induced Muscle Cramps Able to Increase the Cramp Threshold Frequency, When Induced Once a Week?

The cramp threshold frequency (CTF) is known to be positively correlated with the individual cramp susceptibility. Here we assessed CTF changes after two bouts of electrically induced muscle cramps (EIMCs). The EIMCs (6×5 sec) were unilaterally induced twice (separated by one week) in the gastrocnemius of an intervention group (n=8), while 5 participants served as control. The CTF increased from 25.1±4.6 Hz at baseline to 31.4±9.0 Hz and 31.7±8.5 Hz 24 h after bout 1 and 2 (P<0.05). Thereafter, the CTF declined following both bouts to reach values of 28.0±6.7 Hz and 29.1±7.7 Hz after 72 h after bout 1 and 2. Creatine kinase (CK) activity and perceived discomfort during cramps was lower after bout 2 (P<0.05). CTF, CK, and discomfort did not change in CG. That is, a single bout of EIMCs induces a 24 h CTF increment and a second bout sustains this effect, while perceived discomfort and muscle damage decreases. This short term effect may help athletes to reduce the cramp susceptibility for an important match.

Wilderness Medical Society practice guidelines for the prevention and treatment of heat-related illness: 2014 update

The Wilderness Medical Society (WMS) convened an expert panel to develop a set of evidence-based guidelines for the recognition, prevention, and treatment of heat illness. We present a review of the classifications, pathophysiology, and evidence-based guidelines for planning and preventive measures as well as best practice recommendations for both field and hospital-based therapeutic management of heat illness. These recommendations are graded on the basis of the quality of supporting evidence, and balance between the benefits and risks or burdens for each modality. This is an updated version of the original WMS Practice Guidelines for the Prevention and Treatment of Heat-Related Illness published in Wilderness & Environmental Medicine 2013;24(4):351-361.

Exercise-related transient abdominal pain (ETAP)

Exercise-related transient abdominal pain (ETAP), commonly referred to as ‘stitch’, is an ailment well known in many sporting activities. It is especially prevalent in activities that involve repetitive torso movement with the torso in an extended position, such as running and horse riding. Approximately 70 % of runners report experiencing the pain in the past year and in a single running event approximately one in five participants can be expected to suffer the condition. ETAP is a localized pain that is most common in the lateral aspects of the mid abdomen along the costal border, although it may occur in any region of the abdomen. It may also be related to shoulder tip pain, which is the referred site from tissue innervated by the phrenic nerve. ETAP tends to be sharp or stabbing when severe, and cramping, aching, or pulling when less intense. The condition is exacerbated by the postprandial state, with hypertonic beverages being particularly provocative. ETAP is most common in the young but is unrelated to sex or body type. Well trained athletes are not immune from the condition, although they may experience it less frequently. Several theories have been presented to explain the mechanism responsible for the pain, including ischemia of the diaphragm; stress on the supportive visceral ligaments that attach the abdominal organs to the diaphragm; gastrointestinal ischemia or distension; cramping of the abdominal musculature; ischemic pain resulting from compression of the celiac artery by the median arcuate ligament; aggravation of the spinal nerves; and irritation of the parietal peritoneum. Of these theories, irritation of the parietal peritoneum best explains the features of ETAP; however, further investigations are required. Strategies for managing the pain are largely anecdotal, especially given that its etiology remains to be fully elucidated. Commonly purported prevention strategies include avoiding large volumes of food and beverages for at least 2 hours prior to exercise, especially hypertonic compounds; improving posture, especially in the thoracic region; and supporting the abdominal organs by improving core strength or wearing a supportive broad belt. Techniques for gaining relief from the pain during an episode are equivocal. This article presents a contemporary understanding of ETAP, which historically has received little research attention but over the past 15 years has been more carefully studied.

Muscle Cramping During a 161-km Ultramarathon: Comparison of Characteristics of Those With and Without Cramping

BACKGROUND

This work sought to identify characteristics differing between those with and without muscle cramping during a 161-km ultramarathon.

METHODS

In this observational study, race participants underwent body weight measurements before, during, and after the race; completed a post-race questionnaire about muscle cramping and "near" cramping (controllable, not reaching full-blown cramping), drinking strategies, and use of sodium supplementation during four race segments; and underwent a post-race blood draw for determination of serum sodium and blood creatine kinase (CK) concentrations.

RESULTS

The post-race questionnaire was completed by 280 (74.5 %) of the 376 starters. A post-race blood sample was provided by 181 (61.1 %) of the 296 finishers, and 157 (53.0 %) of finishers completed the post-race survey and also provided a post-race blood sample. Among those who completed the survey, the prevalence of cramping and near cramping was 14.3 and 26.8 %, respectively, with greatest involvement being in the calf (54 %), quadriceps (44 %), and hamstring (33 %) muscles. Those with cramping or near cramping were more likely to have a prior history of muscle cramping during an ultramarathon (p < 0.0001) and had higher blood CK concentrations (p = 0.001) than those without cramping. Weight change during the race, use of sodium supplements, intake rate of sodium in supplements, and post-race serum sodium concentration did not differ between those with and without cramping.

CONCLUSIONS

Muscle cramping is most common in those with a prior history of cramping and greater muscle damage during an ultramarathon, suggesting an association with relative muscular demand. Impaired fluid and sodium balance did not appear to be an etiology of muscle cramping during an ultramarathon.

Active Nutrient acute and active for the prevention of calf muscle cramps

Hintergrund: Spontane, meist nächtliche Krämpfe der Muskulatur der Füße und Waden treten gelegentlich bis häufig bei ca. 40 % der Bevölkerung in Deutschland auf. Ursache sind meist lokale Durchblutungsstörungen als Folge einer Grunderkrankung, Trinkschwäche, Ernährungsstörungen, wie mangelnde Elektrolyt- oder Vitaminzufuhr.

Eine abendliche Physiotherapie, wie Dehnungsübungen oder Anwendung eines Massagerollers zum Ausstreichen von Ödemen haben sich als wirksam erwiesen.

Methode: Eine medikamentöse Prophylaxe, z. B. mit Chininsulfat, sollte nur dann zur Anwendung kommen, wenn alle anderen Maß-nahmen ausgeschöpft sind, im Übrigen sollte sorgfältig vorher das Nutzen-Risiko-Verhältnis abgewogen werden, da es selten zu gefährlichen unerwünschten Reaktionen kommen kann. Neu ist der Ansatz, das Säure-Basen-Verhältnis zu beeinflussen, um einer Übersäuerung des Muskels vorzubeugen. 70 Probanden wurden in die Anwendungsbeobachtung eingeschlossen.

Ergebnisse: Die ersten Ergebnisse veranlassen zu einer optimistischen Beurteilung, um über die Aufnahme von Citrat- und Carbonatsalzen sowie Vitamin-B-Krämpfen vorzubeugen.

Predictors of calf cramping in rugby league

Exercise-associated muscle cramps (EAMC) in the calf are common in rugby league. To date, the etiology and predictors of calf cramping are poorly understood. The aim of this study was to undertake a prospective investigation to identify predictors of calf cramping in rugby league players. Demographic and anthropometric data and calf cramp and injury history were collected in the preseason. Hydration status, number of games played, and calf cramps were recorded on game days. Male rugby league players (n = 103, mean age 18.8 ± 4.1 years) were classified as either EAMC (experienced at least 1 incident of calf cramps in the season) or no EAMC (no calf cramps). The following were investigated as possible predictors of EAMC using logistic regression modeling: competition level, age, ethnicity, playing position, history of cramping, precramping, low back pain, foot orthotic usage, foot posture, foot strike, muscle flexibility, calf girth, hydration status, and number of games played. Half the players, n = 52, experienced at least 1 incidence of calf cramping. Playing in a senior competition level (odds ratio: 0.21; 95% confidence interval: 0.06-0.75; p = 0.016), a history of calf cramping (10.85; 2.16-54.44; p = 0.004), and a history of low back pain resulting in missed field minutes (4.50, 1.37-14.79; p = 0.013) were found to predict EAMC. This study suggests that there is a high incidence of calf cramping in rugby league, especially at senior competition levels, and supports preseason screening in senior players to idetify those at risk of calf cramping and the development of possible preventative strategies.

Heat stress and thermal strain challenges in running

Running well and safely in the heat is challenging for all runners, from recreational to elite. As environmental heat stress (heat stress modulated or augmented by air temperature, humidity, wind speed, and solar radiation) and the intensity and duration of a training run or race increase, so are metabolic heat production, the parallel need for heat transfer from the body to maintain thermal equilibrium, the consequent increase in blood flow to the skin, and the concomitant sweating response progressively and proportionally amplified. An accumulating total body-water deficit from extensive sweating and escalating level of cardiovascular and thermal strain will, in due course, considerably challenge a runner's physiology, perception of effort, and on-course well-being and performance. However, with the appropriate preparation and modifications to planned running intensity and distance, runners can safely tolerate and effectively train and compete in a wide range of challenging environmental conditions. Clinicians play a key role in this regard as an effective resource for providing the most effective guidelines and making the best overall individual recommendations regarding training and competing in the heat.

Golgi tendon organ reflex inhibition following manually applied acute static stretching

Golgi tendon organ disinhibition may contribute to exercise-associated muscle cramp (henceforth referred to as "cramps") genesis. Static stretching pre-exercise is prescribed to prevent cramps based on the assumption golgi tendon organ inhibition remains elevated post-stretching. We determined whether stretching increased gastrocnemius golgi tendon organ inhibition and, if so, the time course of this inhibition post-stretching. Twelve participants' dominant limb medial gastrocnemius inhibition was measured before, and at 1, 5, 10, 15 and 30 min after investigators applied three, 1-min duration stretches. Participants maintained voluntary contraction intensities of 5% of their maximum while the Achilles tendon was stimulated transcutaneously 50 times. Five-hundred millisecond epochs of raw electromyographic activity were band-pass filtered, full-wave rectified and averaged. An algorithm identified inhibitory points and calculated the area, maximum and duration of inhibition. Area of inhibition (F1,14 = 1.5, P = 0.25), maximum inhibition (F1,14 = 0.2, P = 0.72) and duration of inhibition (F1,14 = 1.5, P = 0.24) were unaffected by static stretching over the 30-min post-stretching period. If pre-stretching does prevent fatigue-induced cramping, the mechanism is unlikely to involve the autoinhibition produced by the golgi tendon organ reflex. Further empirical research is needed to validate the proposed link between static stretching and cramping and then to investigate alternative mechanisms.

A promising approach to effectively reduce cramp susceptibility in human muscles: a randomized, controlled clinical trial

Background

To investigate if the cramp threshold frequency (CTF) can be altered by electrical muscle stimulation in a shortened position.

Methods

A total of 15 healthy male sport students were randomly allocated to an intervention (IG, n = 10) and a non-treatment control group (CG, n = 5). Calf muscles of both legs in the IG were stimulated equally twice a week over 6 weeks. The protocol was 3×5 s on, 10 s off, 150 µs impulse width, 30 Hz above the individual CTF, and was at 85% of the maximal tolerated stimulation energy. One leg was stimulated in a shortened position, inducing muscle cramps (CT), while the opposite leg was fixated in a neutral position at the ankle, hindering muscle cramps (nCT). CTF tests were performed prior to the first and 96 h after the 6^th (3 w) and 12^th (6 w) training session.

Results

After 3 w, the CTF had significantly (p<0.001) increased in CT calves from 23.3±5.7 Hz to 33.3±6.9 Hz, while it remained unchanged in nCT (pre: 23.6±5.7 Hz, mid: 22.3±3.5 Hz) and in both legs of the CG (pre: 21.8±3.2 Hz, mid: 22.0±2.7 Hz). Only CT saw further insignificant increases in the CTF. The applied stimulation energy (mA² • µs) positively correlated with the effect on the CTF (r = 0.92; p<0.001).

Conclusions

The present study may be useful for developing new non-pharmacological strategies to reduce cramp susceptibility.

Trial Registry

German Clinical Trials Register DRKS00005312

Efficacy of a massage roller combined with cooling lotion in the prevention of calf muscle cramps

In dieser offenen Anwendungsbeobachtung wurde an 208 Patienten über 4 Wochen geprüft, ob die Kombination des Massagerollers mit der Waden Massage Pflegelotion die Anzahl der Waden- und Fußkrämpfe senken kann. Zur Prophylaxe wurden täglich über mindestens 5 Minuten die betroffenen Muskeln ausgehend von der Großzehe in Rich-tung der Leiste mit dem Massageroller mit mäßig bis mittelstarkem Druck ausgerollt. Bei 151 Patienten zeigte sich eine deutliche Besserung, indem die Frequenz der Wadenkrämpfe um mehr als die Hälfte abnahm bzw. keine Wadenkrämpfe mehr auftraten. Auch die Krampflänge nahm durch Anwendung des Massagerollers bei einem aktuellen Wadenkrampf ab. Die Häufigkeit und Stärke wurde in einem Fragebogen dokumentiert. Schwangere, jüngere Patienten, solche mit Venenerkrankungen und Männer in jedem sowie Frauen im mittleren Alter profitierten von der Anwendung des Massagerollers am besten.

Middle and lower trapezius strengthening for the management of lateral epicondylalgia: a case report

STUDY DESIGN

Case report.

BACKGROUND

Addressing weakness of the shoulder region, especially the rotator cuff and scapular musculature, is often suggested clinically for the treatment of individuals with lateral epicondylalgia. However, to our knowledge, the clinical effectiveness of this approach has not been established.

CASE DESCRIPTION

The patient was a 54-year-old woman with a 5-month history of right lateral elbow pain, whose symptoms were reproduced with clinical tests typically used to diagnose lateral elbow tendinopathy. The patient also demonstrated weakness in her middle and lower trapezius muscles, and the medial border of her scapula, measured with a tape measure, was 11 cm lateral from the spinous processes of the thoracic spine with the patient standing in relaxed stance. Based on improved grip strength and reduced associated elbow pain when tested with the scapula manually corrected in a more adducted position, treatment focused solely on strengthening of the middle and lower trapezius muscles over a 10-week period.

OUTCOMES

Following the intervention, the patient presented with improved scapular position, with the medial border of the scapula being 9 cm lateral to the midthoracic spine. The patient's middle and lower trapezius strength improved from 3+/5 and 4-/5, respectively, to 5/5, and her grip strength from 26.1 to 42.2 kg. The patient's scores on the Disabilities of the Arm, Shoulder and Hand questionnaire also improved from 44.2 at the initial evaluation to 0 at the completion of therapy, with the patient being able to perform all of her daily activities in a pain-free manner.

DISCUSSION

The results of this case report suggest that assessment and treatment of scapular musculature warrant consideration in the management of individuals with lateral epicondylalgia.

LEVEL OF EVIDENCE

Therapy, level 4.

Initial electrical stimulation frequency and cramp threshold frequency and force

CONTEXT

In the electrically induced cramp model, the tibial nerve is stimulated at an initial frequency of 4 Hz with increases in 2-Hz increments until the flexor hallucis brevis cramps. The frequency at which cramping occurs (ie, threshold frequency [TF]) can vary considerably. A potential limitation is that multiple subthreshold stimulations before TF might induce fatigue, which is operationally defined as a decrease in maximal voluntary isometric contraction (MVIC) force, thereby biasing TF.

OBJECTIVE

To determine if TF is similar when initially stimulated at 4 Hz or 14 Hz and if MVIC force is different among stimulation frequencies or over time (precramp, 1 minute postcramp, and 5 minutes postcramp).

DESIGN

Crossover study.

SETTING

Laboratory. Patients or Other Participants: Twenty participants (13 males: age = 20.6 ± 2.9 years, height = 184.4 ± 5.7 cm, mass = 76.3 ± 7.1 kg; 7 females: age = 20.4 ± 3.5 years, height = 166.6 ± 6.0 cm, mass = 62.4 ± 10.0 kg) who were prone to cramps.

INTERVENTION(S)

Participants performed 20 practice MVICs. After a 5-minute rest, three 2-second MVICs were recorded and averaged for the precramp measurement. Participants were stimulated at either 4 Hz or 14 Hz, and the frequency was increased in 2-Hz increments from each initial frequency until cramp. The MVIC force was reevaluated at 1 minute and 5 minutes postcramp.

MAIN OUTCOME MEASURE(S)

The TF and MVIC force.

RESULTS

Initial stimulation frequency did not affect TF (4 Hz = 16.2 ± 3.8 Hz, 14 Hz = 17.1 ± 5.0 Hz; t(19) = 1.2, P = .24). Two participants had inaccurate TFs when initially stimulated at 14 Hz; they cramped at 10 and 12 Hz in the 4-Hz condition. The MVIC force did not differ between initial frequencies (F(1,19) = 0.9, P = .36) but did differ over time (F(2,38) = 5.1, P = .01). Force was lower at 1 minute postcramp (25.1 ± 10.1 N) than at precramp (28.7 ± 7.8 N; P, .05) but returned to baseline at 5 minutes postcramp (26.7 ± 8.9 N; P > .05).

CONCLUSIONS

The preferred initial stimulation frequency might be 4 Hz because it did not alter or overestimate TF. The MVIC force was lower at 1 minute postcramp, suggesting the induced cramp rather than the varying electrical frequencies affected force. A 1- to 5-minute rest should be provided postcramp induction if multiple cramps are induced.