ArticleLiterature Review

Muscle Cramping in Athletes-Risk Factors, Clinical Assessment, and Management

February 2008
Clinics in Sports Medicine 27(1):183-94, ix-x

DOI:10.1016/j.csm.2007.09.006

Source
PubMed

Authors:

Martin Schwellnus

University of Pretoria

Malcolm Collins

University of Cape Town

Exercise associated muscle cramping (EAMC) is defined as a painful, spasmodic, and involuntary contraction of skeletal muscle that occurs during or immediately after exercise. There is a high lifetime prevalence of EAMC in athletes, specifically in endurance athletes. The most important risk factors for EAMC in athletes are a previous history of EAMC, and performing exercise at a higher relative exercise intensity or duration, when compared with normal training and participating in hot and humid environmental conditions. The diagnosis of EAMC is made clinically, and the most effective immediate management of EAMC is rest and passive stretching. The key to the prevention of EAMC is to reduce the risk of developing premature muscle fatigue.

Sex, training variables, history of chronic disease, and chronic injury are risk factors associated with a history of exercise-associated muscle cramping in 10,973 ultramarathon race entrants: a SAFER XXXVIII study

Article

Jun 2024
J SPORT MED PHYS FIT

Background: The prevalence of a history of exercise-associated muscle cramping (hEAMC) among ultramarathon runners is high. While the Comrades is one of the most popular mass community-based participation ultramarathons (90km) globally, research on the epidemiology, clinical characteristics, and risk factors of entrants' lifetime hEAMC are scarce. This research aimed to describe the epidemiology, clinical characteristics, and risk factors of hEAMC among Comrades Marathon entrants. Methods: This was a retrospective, cross-sectional study in which 10973 race entrants of the 2022 Comrades Marathon participated. Entrants completed a prerace medical screening questionnaire that included questions related to the lifetime prevalence (%; 95%CI), severity, treatment and risk factors (demographics, training/racing variables, chronic disease/allergies, injury) for EAMC. Results: 1582 entrants reported hEAMC in their lifetime (14.4% ; 95%CI: 13.77-15.09). There was a significantly (p<0.01) higher prevalence of male (16.10%; 95%CI:15.34-16.90) than female (8.31%; 95%CI: 7.27-9.50) entrants with hEAMC (PR=1.94; 95%CI:1.68-2.23). The prevalence of hEAMC was highest in entrants with a 1) 1 disease increase in composite disease score (PR=1.31; 95%CI:1.25-1.39), 2) history of collapse (PR=1.87; 95%CI 1.47-2.38) 3), 3) past chronic musculoskeletal (MSK) injury (PR=1.71; 95%CI 1.50-1.94) and 4) MSK injury in the previous 12 months (PR=2.38;95%2.05-2.77). Training-related risk factors included an increase of 10km weekly running distance (PR=0.97; 95%CI:0.95-0.99) and a training pace increase of 1min/km (slower) (PR=1.07; 95%CI:1.03-1.12). Conclusions: Future research should investigate the causal relationship between risk factors identified and hEAMC in ultramarathon runners. Findings from this study could assist in effective anticipation and adequate planning for treating EAMC encounters during community-based mass participation events.

History Of Exercise Associated Muscle Cramping Among 10973 Comrades Ultramarathon Race Entrants - A Safer Study: 2591

Article

Sep 2023

Effects of Sodium Intake on Health and Performance in Endurance and Ultra-Endurance Sports

Article

Full-text available

Mar 2022
Int J Environ Res Publ Health

The majority of reviews on sports nutrition issues focus on macronutrients, often omitting or paying less attention to substances such as sodium. Through the literature, it is clear that there are no reviews that focus entirely on the effects of sodium and in particular on endurance sports. Sodium intake, both at high and low doses, has been found to be associated with health and performance issues in athletes. Besides, there have been theories that an electrolyte imbalance, specifically sodium, contributes to the development of muscle cramps (EAMC) and hyponatremia (EAH). For this reason, it is necessary to create this systematic review, in order to report extensively on the role of sodium consumption in the population and more specifically in endurance and ultra-endurance athletes, the relationship between the amount consumed and the occurrence of pathological disorders, the usefulness of simultaneous hydration and whether a disturbance of this substance leads to EAH and EAMC. As a method of data collection, this study focused on exploring literature from 2000–2021. The search was conducted through the research engines PubMed and Scopus. In order to reduce the health and performance effects in endurance athletes, simultaneous emphasis should be placed on both sodium and fluid intake.

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

Article

Nov 2021
CLIN J SPORT MED

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.

Exercise-Associated Muscle Cramps in the Tennis Player

Article

Full-text available

Oct 2020

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.

Conceptual Design of a Massaging Device to Mitigate Exercise Associated Calf Muscle Cramps

Article

Full-text available

Mar 2019

Diana Starovoytova

Exercise-associated muscle-cramping (EAMC) is a-common-condition, experienced by recreational and competitive-athletes, which can potentially-endanger their-health, as-well-as professional-career. This paper reports the-synopsis of a-conceptual-design, simulation, and analysis of a-massaging-device to-mitigate paraphysiologic-EAMC, in-the-calf-area. Document-analysis was utilized as one of the-study-instruments (including published-research on the-concepts of cramps and their-treatments; selected-relevant International-patents; the-use of anthropometric-data in product-design; prior-art on massaging-devices, and selected-devices, currently available at the-market, with their-respective-limitations). The-study applied fundamental-Engineering-principles of product design, and was-carried-out in-compliance with ISO7250: 1996 (Basic-human-body-measurements for technological-design). The-best-ranked-design (out of the 3 design-alternatives, made) was chosen, via Engineering-Design Weighted-Decision-Matrix, and confirmed by the 'Drop and Re-vote' (D & R) method. 2D-drawings, of the-best-design-alternative, were created by computer-aided-design (CAD) AutoCAD-software, while 50 th percentile, adult-male was selected, as a design-target. Relevant-leg and hand-dimensions (one-dimensional measurements), were obtained from published-anthropometric-data-tables. Simulation of Stress-Analysis/Single-Point Static-Analysis (to-detect and eliminate rigid-body-modes; and separate stresses across contact-surfaces) was done by Autodesk Inventor-Version: 2016 (Build 200138000, 138). Conceptual-design of the-massaging-device was optimized according-to results of simulations, calculations, and fundamental engineering-product design principles. The-study also revealed that the-patho-physiology, causing EAMC, is most-likely multi factorial and complex. Overall, the-results of this-concise-study are rather-positive, providing a-good starting-point for advanced-exploration on the-same. Further-improvements and trials, however, are necessary. The-study, hence, recommended: (i) Further-studies, to-optimize the-dimensions of the-device, to-accommodate different-shapes of calf-muscles; (ii) More-advanced-methods, such-as PuCC; AHP, and TRIZ should be considered in-selection of the-best-design-alternative; (iii) Comprehensive-materials-selection should be detailed via Ashby-charts; (iv) To-carry-out a-detail-design; (v) To-fabricate a-prototype; (vi) To-conduct additional-tests (e.g., FEA/FEM) and explorative-use-ability-trials, in-collaboration-with the-department of Medical-Engineering, School of Medicine, MU; and (vii) To-analyze the-marketing-aspect of the-final-device. The-device is potentially-beneficial to sports-health-care-providers, coaches, and athletes; moreover, it could be included into-First-Aid Sport-kit (subject-to satisfactory-trails).

Exercise Associated Muscle Cramps -A Current Perspective

Article

Full-text available

Apr 2017

Exercise-associated muscle cramps (EAMC) are a common condition experienced by recreational and competitive athletes and often require medical attention during or immediately after sports events. Despite the high prevalence of this condition, the etiology of EAMC remains poorly understood, and there is a lack of high levels of evidence to guide the management of this condition. The previous claim as to how EAMC come about is being challenged by more recent evidence suggesting a distinctive mechanism. EAMC has been long attributed to an excessive sweat sodium loss together with dehydration. However, growing evidence suggests that EAMC occurs with sustained and repetitive muscle contraction that results in fatigue. The purpose of this article is to examine the existing scientific evidence in support of various views on the etiology of EAMC and to highlight the most current understanding of this complex condition. Various strategies adopted to treat and prevent EAMC also are discussed even though most of them remain anecdotal and have yet to be substantiated by research experimentation.

An initial prospective exploratory investigation to identify predictors of calf cramping in rugby league players

Article

Dec 2011
J SCI MED SPORT

SVALOVÉ KŔČE – PATOGENÉZA, DIAGNOSTIKA A LIEČBA

Article

Peter Špalek

Centrum pre neuromuskulárne ochorenia, Neurologická klinika SZU UN Bratislava -Ružinov Svalové kŕče sú charakterizované náhlou, bolestivou, mimovôľovou kontrakciou svalu. Anamnéza, objektívne vyšetrenie a la-boratórne vyšetrenia umožňujú diagnostikovať rôzne príčiny svalových kŕčov. Primárne (idiopatické) svalové kŕče, bez známej príčiny, sa vyskytujú u zdravých jedincov. Napriek "benígnemu" charakteru mnohí pacienti vnímajú primárne kŕče ako veľmi obťažujúce. Časté sú najmä u starších osôb a tehotných žien. Vznikajú najmä v noci ako nočné kŕče svalov dolných končatín. Sekundárne svalové kŕče sú zriedkavejšie. Spôsobujú ich viaceré rôzne príčiny: 1. Neurogénne ochorenia – amyotrofická late-rálna skleróza, bulbospinálna amyotrofia, polyneuropatie, radikulopatie, neuromyotónia. 2. Svalové ochorenia – metabolické myopatie, dystrofinopatie, kaveolinopatie, atď. 3. Celkové ochorenia – diabetes mellitus, hypothyreóza, cirhóza, poruchy elektrolytov, renálna insuficiencia, atď. 4. Liekmi a toxínmi indukované svalové kŕče – statíny, fibráty, diuretiká, alkohol, atď. Prvým krokom v diagnostike svalových kŕčov je odlíšenie, či ide o primárne alebo sekundárne kŕče. Liečba primárnych sva-lových kŕčov je symptomatická (antiepileptiká, magnézium, cvičenie, naťahovacie cviky). Pri sekundárnych svalových kŕčoch je rozhodujúca kauzálna, resp. patogenetická liečba základného ochorenia. V článku je uvedený prehľad klinických prejavov, patogenéza, diagnostika a liečba svalových kŕčov. Kľúčové slová: primárne svalové kŕče, sekundárne svalové kŕče, patogenéza, diagnostika, liečba MUSCLE CRAMPS – PATHOGENESIS, DIAGNOSIS AND TREATMENT Muscle cramps are characterized by a sudden, painful, involuntary contraction of muscle. Medical history, physical exami-nation, and laboratory test help to determine the various causes of muscle cramps. Primary (or idiopathic) muscle cramps, without known cause, occur normally in healthy persons. Despite the "benign" nature, many patients find idiopathic cramps very uncomfortable. They are frequent especially in elderly and pregnant women, presenting usually at night as nocturnal leg cramps. Secondary muscle cramps are not so frequent. They are caused by multiple divers causes: 1. Neurogenic disorders -amyotrophic lateral sclerosis, bulbospinal amyotrophy, polyneuropathies, radiculopathies, acquired neuromyotonia. 2. Muscle disorders -metabolic myopathies, dystrophinopathies, caveolinopathies, etc. 3. Systemic disorders -diabetes, hypothyroidism, cirrhosis, electrolyte disturbances, uremia, etc. 4. Drug and toxin induced cramps -statins, fibrates, diuretics, ethanol, etc. The first diagnostic step in a patient with muscle cramp is to find out if the cramps are of primary or secondary origin. Treat-ment of primary muscle cramps is empiric (antiepileptics, magnesium, stretching exercises). In patients with secondary muscle cramps the pathogenic therapy of underlying disease is of crucial importance. This paper covers the pathogenesis, clinical presentation, diagnosis and treatment of muscle cramps.

Predictors of Calf Cramping in Rugby League

Article

Jun 2013
J STRENGTH COND RES

Exercise-Associated Muscle Cramps (EAMC) in the calf are common in rugby league. To date, the aetiology 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, as well as 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 one 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 modelling: competition level, age, ethnicity, playing position, history of cramping, pre-cramping, 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 one incidence of calf cramping. Playing in a senior competition level (OR 0.21; 95% CI 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 pre-season screening in senior players to identify those at risk of calf cramping and the development of possible preventative strategies.

Comparative study of cold compress and liniment treatment as an adjunct to massage therapy for exercise-associated muscle cramps (EAMC) among young athletes in the Philippine setting

Article

Full-text available

Sep 2021

Exercise-associated muscle cramps (EAMC) is prevalent among athletes during training or competitions where they are subjected to strenuous activities for a prolonged period. To manage this painful condition, health practitioners have used numerous treatment modalities having massage done with adjunct application such as cold compress or liniment. Studies show that it is debatable which combination of treatment modalities is more effective on people affected by EAMC. Hence, this study aimed to present evidence-based data to show if there is a difference in the effectiviteness of the two modalities in treating EAMC. A total of thirty-two (32) athletic participants were enrolled in this study and a total of 40 treatment trials were included in the analysis of data. Each participant performed strenuous exercises meant to induce muscle cramps. The onset of muscle cramps was identified using a set criteria. After which, treatment was applied and the length of time that the cramp was resolved was recorded. Determining relief from muscle cramps was based on the characteristic of muscle hardness and the level of pain by using a numerical rating scale. Results showed that though majority of the participants verbalized preference for the ice treatment, analysis of data using one-way ANOVA revealed that there is no evidence to prove that there is a difference in the effectivity among the treatment modalities performed. In conclusion, though all modalities performed were able to relieve the EAMC, the use of adjunct treatment in addition to massage and stretching may have a placebo effect component, which improves the patient's perception of greater efficacy.

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

Article

Full-text available

Mar 2021
Sports Nutr Rev J

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.

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

Preprint

Full-text available

Oct 2020

Background: Muscle cramp is a painful, involuntary muscle contraction, and occurs during or following exercise, which is referred to as exercise-associated muscle cramp (EAMC). The causes of EAMC are likely to be multifactorial, but dehydration and electrolytes deficits have been 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 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 by 3.8 ± 2.7 to 4.5 ± 1.7 Hz from immediately to 65 min post-DHR for the spring water condition, but increased by 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.

Sweat Characteristics in Individuals With Varying Susceptibilities of Exercise-Associated Muscle Cramps

Article

May 2020

Szymanski, M, Miller, KC, O'Connor, P, Hildebrandt, L, and Umberger, L. Sweat characteristics in individuals with varying susceptibilities of exercise-associated muscle cramps. J Strength Cond Res 36(5): 1171-1176, 2022-Many medical professionals believe dehydration and electrolyte losses cause exercise-associated muscle cramping (EAMC). Unlike prior field studies, we compared sweat characteristics in crampers and noncrampers but accounted for numerous factors that affect sweat characteristics including initial hydration status, diet and fluid intake, exercise conditions, and environmental conditions. Sixteen women and 14 men (mean ± SD; age = 21 ± 2 year, body mass = 69.1 ± 11.6 kg, height = 171.4 ± 9.9 cm) self-reported either no EAMC history (n = 8), low EAMC history (n = 10), or high EAMC history (n = 12). We measured V̇o2max, and subjects recorded their diet. At least 3 days later, subjects ran at 70% of their V̇o2max for 30 minutes in the heat (39.9 ± 0.6° C, 36 ± 2% relative humidity). Dorsal forearm sweat was collected and analyzed for sweat sodium concentration ([Na+]sw), sweat potassium concentration ([K+]sw), and sweat chloride concentration ([Cl-]sw). Sweat rate (SWR) was estimated from body mass and normalized using body surface area (BSA). Dietary fluid, Na+, and K+ ingestion was estimated from a 3-day diet log. We observed no differences for any variable among the original 3 groups (p = 0.05-p = 0.73). Thus, we combined the high and low cramp groups and reanalyzed the data against the noncramping group. Again, there were no differences for [Na+]sw (p = 0.68), [K+]sw (p = 0.86), [Cl-]sw, (p = 0.69), SWR/BSA (p = 0.11), dietary Na+ (p = 0.14), dietary K+ (p = 0.66), and fluid intake (p = 0.28). Fluid and electrolyte losses may play a more minor role in EAMC genesis than previously thought.

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

Article

Full-text available

Jun 2015

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

Exercise associated muscle cramps: Discussion on causes, prevention and treatment

Article

Full-text available

Oct 2014
SCI SPORT

Pascal Edouard

Objective: To discuss the causes, prevention and treatment of exercise associated muscle cramps (EAMC) according to the level of evidence of the available literature, in order to present some evidence-based guidelines for athletes, coaches and health professionals. News: Since it appears fundamental for sports medicine physicians and sports health professionals to be able to manage and prevent EAMC, although pathophysiology and causes of EAMC are discussed, clear understanding of EAMC causes seems important in order to treat and prevent EAMC. Perspectives and projects: The present review evaluated the available literature on EAMC based on their level of evidence to present some evidence-based guidelines for sports professionals. Fifty articles were selected: 24 after full-text reading and 26 articles after screening selected articles references. Level of evidence was from 1 (n= 3), 2 (n= 8), 3 (n= 10), 4 (n= 13), and 5 (n= 16). Conclusions: The "Altered neuromuscular control theory" seems to be the most scientifically acceptable theory, and suggests that EAMC are caused by an imbalance between increased afferent activity (e.g. muscle spindle, Ia) and decreased inhibitory afferent activity (e.g. Golgi tendon organs, Ib) which leads to increased α-motor neuron activity and muscle cramping, especially with muscle contraction in a shortened position. EAMC prevention measures should take into account the preparation of muscle to exercise (adapted training) and the respect of muscle fatigue during exercise (warm-up before exercise, well-controlled effort and rest during exercise). EAMC treatments should be non-pharmacological and should play a role on neuromuscular control (rest and/or stretching).

Intravenous Fluid Use in Athletes

Article

Jul 2012

Time allowing, euhydration can be achieved in the vast majority of individuals by drinking and eating normal beverages and meals. Important to the competitive athlete is prevention and treatment of dehydration and exercise-associated muscle cramps, as they are linked to a decline in athletic performance. Intravenous (IV) prehydration and rehydration has been proposed as an ergogenic aid to achieve euhydration more effectively and efficiently. PubMed database was searched in November 2011 for all English-language articles related to IV utilization in sport using the keywords intravenous, fluid requirements, rehydration, hydration, athlete, sport, exercise, volume expansion, and performance. Limited evidence exists for prehydration with IV fluids. Although anecdotal evidence does exist, at this time there are no high-level studies confirming that IV prehydration prevents dehydration or the onset of exercise-associated muscle cramps. Currently, there are no published studies describing IV fluid use during the course of an event, at intermission, or after the event as an ergogenic aid. The use of IV fluid may be beneficial for a subset of fluid-sensitive athletes; this should be reserved for high-level athletes with strong histories of symptoms in well-monitored settings. Volume expanders may also be beneficial for some athletes. IV fluids and plasma binders are not allowed in World Anti-Doping Agency-governed competitions. Routine IV therapy cannot be recommended as best practice for the majority of athletes.

Topical Delivery of Methocarbamol Loaded Nanoemulgel - in-vitro Characterization

Article

Full-text available

Nov 2021
INDIAN J PHARM EDUC

Background: Methocarbamol is used as skeletal muscle relaxant. Nanoemulgel is currently being developed as a transdermal drug delivery technology because to its nanosized droplets, which provide superior effectiveness with reduced toxicity. Aim: The aim of the study is to prepare and characterize the Methocarbamol loaded nanoemulgel. Materials and Methods: The required quantity of Methocarbamol dissolved in Acconon oil, surfactant and co-surfactant used to prepare nanoemulsion with various ratios using probe sonicator and poured into the prepared carbopal gel with constant stirring. The prepared nanomelgel was characterized for its pH, viscosity, particle size and zeta potential, surface morphology by TEM, drug content and in-vitro Methocarbamol release from developed formulation. Results: The developed NEs formulation exhibited acceptable pH range around 6 to 7, viscosity was in the range of 38.26cps to 45.25cps. The average droplet size of the NE formulations varied from 20.1 to 56.4 nm. There is no much change of droplet size when varying the oil concentration of the NEs. The result of the droplet polydispersity index (PDI) shows the droplets are uniformly distributed. The zeta potential of the formulations ranging from -0.1mV to 0.3mV for NE and NE-Gel respectively. This is due to the presence of the non-ionic surfactant over the droplet. The TEM micrograph of the 10% NEs and NE-Gel appears spherical in nature with drug embedded in the oil droplet. The volume of drug release for 3% Nanoemulsion is 64.28%, 50.78%, 41.78%, 38.57% and 3% Nanoemulgel is 29.57%, 38.25%, 43.71%, 52.39% respectively. Due to higher quantity of oil phase of NE and rigid gel nature the in-vitro resulted in delaying and sustaining in drug release. Conclusion: Hence, we conclude that the developed NE, NE-Gel might be beneficial for the better topical delivery of muscle relaxant.

What is the role of magnesium for skeletal muscle cramps? A Cochrane Review summary with commentary

Article

Full-text available

Mar 2021

Antimo Moretti

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

Article

Aug 2020

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.

Suplementação oral de magnésio na prevenção de cãibras musculares: revisão baseada na evidência

Article

Full-text available

Feb 2020

Aim: Evidence review on the efficacy of oral magnesium supplementation in the prevention of muscle cramps without associated pathology, in adults. Data sources: National Guideline Clearinghouse, Canadian Medical Association Practice Guidelines Infobase, Guidelines Finder, The Cochrane Library, DARE, Bandolier, Evidence-Based Medicine Online, and PubMed. Methods: On 4th July 2018, using the MeSH terms Muscle Cramp, Magnesium and Magnesium Compounds, we searched for meta-analyses, systematic reviews, randomized controlled trials (RCT), observational studies and clinical guidelines published in Portuguese, Spanish, and English. To assign levels of evidence (LE) and strength of recommendations, the Strength of Recommendation Taxonomy (SORT) scale of the American Academy of Family Physicians was used. Results: We found 47 articles, of which five met the inclusion criteria: one meta-analysis (LE 2), three systematic reviews (LE 2) and one RCT (LE 2). No studies related to exercise-associated cramps were found. Studies are consensual in the apparent lack of efficacy of the magnesium in the prevention of idiopathic muscle cramps. As for the pregnancy-associated cramps, the evidence is inconsistent. However, the use of small samples, short follow-up periods and the heterogeneity of methodologies (population, supplement type, posology, and outcomes) compromise the extrapolation and reduce the strength of the conclusions obtained. Conclusion: According to the evidence found, oral magnesium supplementation in the general population seems to be ineffective in preventing idiopathic muscle cramps (SORT B), therefore, with no evidence to support its routine prescription in clinical practice. In pregnancy-associated cramps, the evidence of oral magnesium supplementation is unclear (SORT B). To achieve more robust conclusions, higher quality RCT is needed, with more homogeneous methodologies.

Muscle cramps: A comparison of the two-leading hypothesis

Article

May 2018
J ELECTROMYOGR KINES

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

Article

Aug 2017
CLIN J SPORT MED

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.

Article

Full-text available

Jul 2017
SAMJ S AFR MED J

Wilderness heat-related illnesses span a variety of conditions caused by excessive or prolonged heat exposure, and/or the inability to compensate adequately for increased endogenous production during strenuous outdoor activities. Despite management of well-known risk factors, such as lack of fitness or acclimatisation, dehydration, underlying illness and certain medications, even highly trained individuals may exceed their physiological capability to dissipate increased core temperature. Heat illnesses range from benign cramps to the more concerning heat syncope and exercise-associated collapse (with or without hyperthermia), and culminate in life-threatening heat stroke. The differential diagnosis in the wilderness is broad and should include exercise-associated hyponatraemia with or without encephalopathy. Clinical guidelines for wilderness and hospital management of these conditions are available. Field management and evacuation are based on severity, and include cooling, rehydration and assessment of core temperature and serum sodium, if possible. Hyponatraemia should be corrected with the use of oral or intravenous hypertonic saline, depending on whether the patient can safely take oral fluids. Hospital management may include aggressive and potentially invasive cooling, careful assessment for organ dysfunction, and intensive multi-organ support, if required. Paracetamol, non-steroidal anti-inflammatory drugs and dantrolene should not be used. © 2017, South African Medical Association. All rights reserved.

Cardiovascular Responses to Body Fluid Imbalance

Chapter

Full-text available

Dec 2015

Heat Stress and Thermal Strain Challenges in Running

Article

Aug 2014

Michael F. Bergeron

Synopsis: 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.

Plasma Potassium Concentration and Content Changes After Banana Ingestion in Exercised Men

Article

Nov 2012
J ATHL TRAINING

Kevin Miller

Individuals prone to exercise-associated muscle cramps (EAMCs) are instructed to eat bananas because of their high potassium (K(+)) concentration and carbohydrate content and the perception that K(+) imbalances and fatigue contribute to the genesis of EAMCs. No data exist about the effect of bananas on plasma K(+) concentration ([K(+)](p)) or plasma glucose concentration ([glucose](p)) after exercise in the heat. To determine whether ingesting 0, 1, or 2 servings of bananas after 60 minutes of moderate to vigorous exercise in the heat alters [K(+)](p) or [glucose](p) and whether changes in [K(+)](p) result from hypotonic fluid effluxes or K(+) ion changes. Crossover study. Laboratory. Patients or Other Participants: Nine euhydrated men (age = 27 ± 4 years, height = 180.3 ± 8.4 cm, mass = 84.9 ± 26.1 kg, urine specific gravity ≤ 1.006) without EAMCs volunteered. Intervention(s): On 3 separate days, participants completed 60 minutes of moderate to vigorous cycling (temperature = 36.4°C ± 1.1°C, relative humidity = 19.4% ± 2.5%) and then ate 0 g (0 servings), 150 g (1 serving), or 300 g (2 servings) of bananas. Blood samples were collected at 3, 5, 15, 30, and 60 minutes postingestion. Main Outcome Measure(s): The [K(+)](p), changes in plasma K(+) content, plasma volume changes, and [glucose](p). The [K(+)](p) differed between conditions at 60 minutes; 2 servings (4.6 ± 0.3 mmol/L [conventional unit = 4.6 ± 0.3 mEq/L]) was greater than 1 serving (4.5 ± 0.2 mmol/L [conventional unit = 4.5 ± 0.2 mEq/L]) and 0 servings (4.4 ± 0.3 mmol/L [conventional unit = 4.4 ± 0.3 mEq/L]) (P < .05). The [K(+)](p) was greater at 60 minutes than at 3 and 5 minutes in the 1-serving condition and was greater at 30 and 60 minutes than at 3 and 5 minutes in the 2-servings condition (P < .05). Percentage change in K(+) content was greater only at 30 and 60 minutes postingestion than at baseline in the 2-servings condition (4.4% ± 3.7% and 5.8% ± 2.3% increase, respectively) (P < .05). The plasma volume changes among conditions were unremarkable. The [glucose](p) was greater in the 2-servings condition than in all other conditions at 15, 30, and 60 minutes (P < .05). The effect of banana ingestion on EAMCs is unknown; however, these data suggested bananas are unlikely to relieve EAMCs by increasing extracellular [K(+)] or [glucose](p). The increases in [K(+)](p) were marginal and within normal clinical values. The changes in [K(+)](p), plasma K(+) content, and [glucose](p) do not occur quickly enough to treat acute EAMCs, especially if they develop near the end of competition.

Deportes específicos y lesiones asociadas

Chapter

Jan 2013

Gregory L. Landry

Her Yaş İçin Esneklik ve Egzersiz Örnekleri

Chapter

Full-text available

Dec 2023

Bu bölüm, esnekliğin her yaş grubundaki önemini ve bu yaş gruplarına uygun egzersiz önerilerini kapsamaktadır. Çocuklar için esneklik egzersizlerinin, fiziksel uygunluğu artırdığı ve motor becerileri geliştirdiği belirtilirken, yaşlı bireylerde ise esnekliği korumanın günlük yaşam aktivitelerini kolaylaştırdığı ve düşme riskini azalttığı vurgulanmaktadır. Ayrıca, dinamik ve statik germe teknikleri gibi farklı esneklik egzersizlerinin nasıl uygulanacağı, egzersizlerin sıklığı ve süresi hakkında detaylı bilgiler verilmektedir. Çocuklar için yaşa göre değişen esneklik seviyeleri ve uygun egzersiz türleri tartışılırken, yaşlılar için haftada en az iki gün, seans başı en az 10 dakika süren egzersizlerin, boyun, omuzlar, sırt ve bacaklar gibi önemli bölgelerde esnekliği artırdığı belirtilmektedir. Pilates ve yoga gibi disiplinlerin, esneklik egzersizleri olarak zihinsel ve fiziksel sağlığa katkıları da ele alınmaktadır .

Impact of Weather and Climate Change on Mass Gathering Events

Chapter

Apr 2024

Mass medical deployments to large events, such as music festivals or sporting events, are increasing in number, size, and complexity. This textbook provides guidance and direction for rational, effective, and practical medical management of mass gathering events for medical leaders. This is the first authoritative text on mass event medicine, filling a much-needed gap in a large and important area of the specialty. An international group of contributors introduce the specialty and cover topics such as general deployment, staffing, equipment, and resources, moving on to more complex issues such as the business aspect of mass gathering medicine and the legal implications. There are also practical chapters on specific types of events and adverse events such as terrorism, severe weather, and civil disobedience. An invaluable text for all healthcare professionals planning for and attending mass events, particularly EMS professionals, large event planners and administrators, and law enforcement and security personnel.

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

Article

Full-text available

Mar 2024

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.

Hematologic and Endocrine Conditions: Exercise Collapse-Associated with Sickle Cell Trait, Exertional Rhabdomyolysis, Hyperglycemia, and Hypoglycemia

Chapter

Jan 2024

Exercise collapse associated with sickle cell trait (ECAST) occurs in those with sickle cell trait and is generally a benign condition. However, athletes exercising at near maximal exertion without adequate interval rest periods are at risk of this condition which ranges from mild weakness to fulminant disease. Early recognition and preventative measures are crucial for keeping athletes with sickle cell trait safe during exercise. Exertional rhabdomyolysis is a clinical syndrome that occurs in the setting of strenuous activity and is characterized by muscle necrosis leading to the release of intracellular components into the systemic circulation. Athletes with rhabdomyolysis can have a host of signs and symptoms that range from mild to multi-organ failure. Initial management is based on the severity of an athlete’s clinical presentation and point-of-care testing. Hypoglycemia and hyperglycemia are important endocrine conditions that can occur in athletes with or without diabetes mellitus. Hypoglycemic episodes should be carefully monitored as severe hypoglycemia can be life-threatening, leading to obtundation and seizures. Management involves withholding the athlete from exercising, providing oral carbohydrates, turning off insulin, and/or providing glucagon. On the other hand, uncontrolled hyperglycemia can lead to severe conditions such as diabetic ketoacidosis and hyperosmolar hyperglycemic state but typically only occur in those with diabetes mellitus.

Muskelzuckungen und Muskelkrämpfe – Differenzialdiagnosen und elektrophysiologische Diagnostik

Article

Mar 2023

Muskelzuckungen und -krämpfe sind Beschwerden, die vom harmlosen Symptom bis hin zu Symptomen einer schwerwiegenden neurologischen Erkrankung reichen können. Eine ausführliche Anamnese, gründliche neurologische Untersuchung und elektrophysiologische Untersuchungen ermöglichen die Unterscheidung der verschiedenen Ätiologien. In diesem Artikel werden verschiedene Ursachen unter Berücksichtigung deren Definition, der elektrophysiologisch zugrunde liegenden Phänomene und deren differenzialdiagnostischer Einordnung dargestellt.

Specific Sports and Associated Injuries

Chapter

Jan 2011

Gregory L. Landry

A Sequential Application of Qualitative Methods to Develop a Population Based Tool for Identifying and Managing Exertional Heat Illness

Article

Full-text available

Jul 2022

Problem: United States (U.S.) National Guard (NG) units train annually to respond to natural and human-caused disasters. Given seasonal weather and climate extremes, no specific EHI risk assessment tool exists for medical personnel to assess EHI risk both before, during and after each day of training or response. With personnel wearing impermeable personal protective equipment (all hazard suits and respirators), these personnel are at increased risk for EHI. Purpose: EHI risk factors were identified, and clinical management guidelines were developed using qualitative methods involving focus groups, content experts and a Delphi panel. Methods: A 4-phase approached was utilized: focus groups, content panel experts to estimate content validity of the revised SF-600 and a Delphi panel to estimate the content validity of the field and clinical management care guidelines to be used in conjunction with the SF-600R. The fourth phase was piloting the SF600R to compare with the current SF600. Results: Focus group data revealed human, environmental, and workplace/social factors as indicators associated with EHI. Content expert consensus was reached for sleep, fitness, acclimatization, sickle cell trait, medications, and hyper-motivation factors. Delphi panel results were used to confirm evidence-based field/pre-transport guidelines for managing EHI in CERF-P/HRF operations. A revised SF 600 was developed and piloted during a limited 2-day training exercise. Readability, time to completion by service members and medical teams, and capture of additional evidence-based risk factors were evaluated with a sub-set of 250 NG personnel (n=38). Conclusion: Screening and assessment of NG personnel before disaster deployment and post-screening evaluations must utilize current evidence on prevention and identification of EHI risk. Medical group leadership need to engage in more strategic planning and discussion to utilize the SF600 Pre and Post Event Screening form as a risk-based safety tool to reduce EHI incidence during training exercises and real-world response deployments. Keywords: Haddon’s Matrix, Exertional Heat Illness, Focus groups, Qualitative Research, Military

Pouzdanost hrvatske verzije upitnika za procjenu uživanja u tjelesnoj aktivnosti kod studenata Sveučilišta u Zagrebu

Conference Paper

Full-text available

Jun 2021

Kako je pojava nove bolesti COVID-19 promijenila dosadašnji, uobičajeni način izvođenja nastave TZK te uzrokovala potpuno novi pristup njezinu izvođenju uz implementaciju i primjenu informacijsko-komunikacijske tehnologije (IKT), primarni je cilj ovoga istraživanja ispitati pomaže li novi oblik nastave TZK učenicima i studentima da ostanu tjelesno aktivni u uvjetima ograničenoga kretanja. Sljedeći je cilj je ispitati jesu li učenici i studenti zadovoljni ponuđenim modelom nastave TZK te postoje li razlike po dobi. Uzorak je obuhvatio ukupno 309 ispitanika (182 žene ili 58,9%; 127 muškaraca ili 41,1%), odnosno 166 studenata (84 studentice i 82 studenta) Sveučilišta u Zagrebu (dob: 20,31 ± 0,99 godina) te 143 učenika (98 učenica i 45 učenika) gimnazije iz Slavonije (dob: 16,49 ± 1,17). Ispitanici su anonimni upitnik ispunjavali dobrovoljno tijekom sedmog tjedna nastave na daljinu. Podaci su obrađeni kompjutorskim statističkim programom Statistika 13.5.0.17. Izračunati su osnovni deskriptivni pokazatelji te χ2 -test za nezavisne uzorke. Za sve varijable određene su frekvencije odgovora, a χ2 -test nezavisnosti (uz korekciju neprekidnosti prema Yatesu) pokazao je statistički značajnu povezanost dobi i stava o utjecaju nastave TZK na daljinu na tjelesnu aktivnost u vrijeme pandemije, c2 (1, n=309) = 19,68, p=0,00. Također, χ2 -test nezavisnosti (uz korekciju neprekidnosti prema Yatesu) pokazao je statistički značajnu povezanost dobi i želje za samostalnim odabirom vježbi, c2 (1, n=309) = 91,7, p=0,00. Novi oblik nastave TZK, odnosno nastava na daljinu primjenom IKT-a pomaže učenicima i studentima da ostanu tjelesno aktivni u vrijeme pandemije bolesti COVID-19.

Magnesium for skeletal muscle cramps

Article

Full-text available

Sep 2020

Background: Skeletal muscle cramps are common and often occur in association with pregnancy, advanced age, exercise or motor neuron disorders (such as amyotrophic lateral sclerosis). Typically, such cramps have no obvious underlying pathology, and so are termed idiopathic. Magnesium supplements are marketed for the prophylaxis of cramps but the efficacy of magnesium for this purpose remains unclear. This is an update of a Cochrane Review first published in 2012, and performed to identify and incorporate more recent studies. Objectives: To assess the effects of magnesium supplementation compared to no treatment, placebo control or other cramp therapies in people with skeletal muscle cramps. SEARCH METHODS: On 9 September 2019, we searched the Cochrane Neuromuscular Specialised Register, CENTRAL, MEDLINE, Embase, LILACS, CINAHL Plus, AMED, and SPORTDiscus. We also searched WHO-ICTRP and ClinicalTrials.gov for registered trials that might be ongoing or unpublished, and ISI Web of Science for studies citing the studies included in this review. Selection criteria: Randomized controlled trials (RCTs) of magnesium supplementation (in any form) to prevent skeletal muscle cramps in any patient group (i.e. all clinical presentations of cramp). We considered comparisons of magnesium with no treatment, placebo control, or other therapy. Data collection and analysis: Two review authors independently selected trials for inclusion and extracted data. Two review authors assessed risk of bias. We attempted to contact all study authors when questions arose and obtained participant-level data for four of the included trials, one of which was unpublished. We collected all data on adverse effects from the included RCTs. Main results: We identified 11 trials (nine parallel-group, two cross-over) enrolling a total of 735 individuals, amongst whom 118 cross-over participants additionally served as their own controls. Five trials enrolled women with pregnancy-associated leg cramps (408 participants) and five trials enrolled people with idiopathic cramps (271 participants, with 118 additionally crossed over to control). Another study enrolled 29 people with liver cirrhosis, only some of whom suffered muscle cramps. All trials provided magnesium as an oral supplement, except for one trial which provided magnesium as a series of slow intravenous infusions. Nine trials compared magnesium to placebo, one trial compared magnesium to no treatment, calcium carbonate or vitamin B, and another trial compared magnesium to vitamin E or calcium. We judged the single trial in people with liver cirrhosis and all five trials in participants with pregnancy-associated leg cramps to be at high risk of bias. In contrast, we rated the risk of bias high in only one of five trials in participants with idiopathic rest cramps. For idiopathic cramps, largely in older adults (mean age 61.6 to 69.3 years) presumed to have nocturnal leg cramps (the commonest presentation), differences in measures of cramp frequency when comparing magnesium to placebo were small, not statistically significant, and showed minimal heterogeneity (I² = 0% to 12%). This includes the primary endpoint, percentage change from baseline in the number of cramps per week at four weeks (mean difference (MD) -9.59%, 95% confidence interval (CI) -23.14% to 3.97%; 3 studies, 177 participants; moderate-certainty evidence); and the difference in the number of cramps per week at four weeks (MD -0.18 cramps/week, 95% CI -0.84 to 0.49; 5 studies, 307 participants; moderate-certainty evidence). The percentage of individuals experiencing a 25% or better reduction in cramp rate from baseline was also no different (RR 1.04, 95% CI 0.84 to 1.29; 3 studies, 177 participants; high-certainty evidence). Similarly, no statistically significant difference was found at four weeks in measures of cramp intensity or cramp duration. This includes the number of participants rating their cramps as moderate or severe at four weeks (RR 1.33, 95% CI 0.81 to 2.21; 2 studies, 91 participants; moderate-certainty evidence); and the percentage of participants with the majority of cramp durations of one minute or more at four weeks (RR 1.83, 95% CI 0.74 to 4.53, 1 study, 46 participants; low-certainty evidence). We were unable to perform meta-analysis for trials of pregnancy-associated leg cramps. The single study comparing magnesium to no treatment failed to find statistically significant benefit on a three-point ordinal scale of overall treatment efficacy. Of the three trials comparing magnesium to placebo, one found no benefit on frequency or intensity measures, another found benefit for both, and a third reported inconsistent results for frequency that could not be reconciled. The single study in people with liver cirrhosis was small and had limited reporting of cramps, but found no difference in terms of cramp frequency or cramp intensity. Our analysis of adverse events pooled all studies, regardless of the setting in which cramps occurred. Major adverse events (occurring in 2 out of 72 magnesium recipients and 3 out of 68 placebo recipients), and withdrawals due to adverse events, were not significantly different from placebo. However, in the four studies for which it could be determined, more participants experienced minor adverse events in the magnesium group than in the placebo group (RR 1.51, 95% CI 0.98 to 2.33; 4 studies, 254 participants; low-certainty evidence). Overall, oral magnesium was associated with mostly gastrointestinal adverse events (e.g. diarrhoea), experienced by 11% (10% in control) to 37% (14% in control) of participants. Authors' conclusions: It is unlikely that magnesium supplementation provides clinically meaningful cramp prophylaxis to older adults experiencing skeletal muscle cramps. In contrast, for those experiencing pregnancy-associated rest cramps the literature is conflicting and further research in this population is needed. We found no RCTs evaluating magnesium for exercise-associated muscle cramps or disease-state-associated muscle cramps (for example amyotrophic lateral sclerosis/motor neuron disease) other than a single small (inconclusive) study in people with liver cirrhosis, only some of whom suffered cramps.

Magnesium for skeletal muscle cramps Review information Review number: 163 Contact person

Article

Full-text available

Jul 2020

Muscle cramps are common and can occur in a wide range of settings. Older adults and pregnant women commonly complain of leg cramps while they are resting, athletes can cramp when they are pushing the limits of their endurance, and some people develop muscle cramps as a symptom of other medical conditions. One potential treatment that is already being marketed to prevent muscle cramps is magnesium supplementation. Magnesium is a common mineral in our diets and extra oral supplements of this mineral are available either over the Internet or in health food stores and pharmacies (usually in the form of tablets or powders to be dissolved in water). We searched for all high quality published studies evaluating the effectiveness of magnesium to prevent muscle cramps and found four studies in older adults and three studies in pregnant women. There were no studies of people who cramp while exercising and no studies on people who cramp because of underlying medical problems. The four studies in older adults (a total of 322 participants including controls in cross-over studies) collectively suggest that magnesium is unlikely to provide a meaningful benefit in reducing the frequency or severity of cramps in that population. We consider this evidence to be of moderate quality. In contrast, the three studies in pregnant women (202 participants) are collectively inconclusive since one study found benefit in reducing both cramp frequency and cramp pain while the other two found no benefit. More research on magnesium in pregnant women is needed; however, older adult cramp sufferers appear unlikely to benefit from this therapy. While we could not determine the rate of unwanted side effects, the study withdrawal rates and adverse event discussions suggest the treatment is well tolerated.

Muscles

Chapter

Apr 2020

Muscle injuries are very common in all ages and different types of sports. They represent over 30% of all sports-related injuries and are a major reason for missed playing time (Grassi et al., Joints 4:39–46, 2016; Valle, Br J Sports Med 45:e2, 2011; Mueller-Wohlfahrt et al., Br J Sports Med 47:342–350, 2012). The more common muscles injuries are strains, hematomas/contusions, cramps, rhabdomyolysis, and chronic exertional compartment syndrome. This chapter addresses, in detail, the presentation, diagnosis, acute and long-term management, and prevention of these frequently encountered injuries in the sports medicine community. It also discusses when an athlete can safely return to play after sustaining a muscle injury which is a difficult decision and involves a group conversation between the athlete, physicians, coaches, athletic trainers, and physical therapists.

Fruits

Chapter

Full-text available

Feb 2020

Fruits come in a wide variety of colors, shapes, and flavors. This chapter will cover selected fruits that are known to be healthy and highly nutritious. These fruits were chosen due to their common usage and availability. Since it is not possible to cover all health benefits or essential nutrients and important phytochemicals of the fruit composition, this chapter will focus on the key valuable constituents and their potential health effects.

Exercise-Associated Muscle Cramps

Chapter

Jan 2020

Kevin Miller

Exercise-associated muscle cramps (EAMC) are painful, involuntary skeletal muscle contractions during and after exercise. Despite EAMC being the most prevalent heat-related illness in athletes, their cause remains unclear and controversial. Contrary to popular opinion, most recent observational and experimental evidence suggests EAMC are not solely due to dehydration or electrolyte imbalances. Rather, it is likely EAMC stem from a convergence of an individual’s intrinsic and extrinsic risk factors which act to alter central and peripheral nervous system excitability. Unfortunately, the lack of a clear etiology for EAMC has spawned numerous myths and anecdotes regarding the most effective treatment and prevention strategies. However, the treatment for an athlete experiencing EAMC remains gentle static stretching until the EAMC abate. The most effective EAMC prevention strategy is less clear. EAMC prevention strategies should be tailored to an individual’s unique risk factors following a thorough medical evaluation and screening. Clinicians should avoid generalized treatment advice (e.g., drink more fluids or sports drinks) since it can result in disastrous outcomes such as exertional hyponatremia.

Exertional Heat Illnesses

Chapter

Feb 2018

Exercising in hot, humid environments can have a negative impact on exercise performance and one’s health. Strategies such as gradually becoming accustomed to exercise in new environments, adequate hydration and nutrition, and appropriate work-to-rest ratios can help decrease the risk of exertional heat illness. If an exertional heat illness does occur, it is imperative to rapidly recognize the condition and provide appropriate treatment. Rapid recognition and rapid cooling are essential for survival in cases of exertional heat stroke, which can be fatal. Determining the cause of the heat illness is key to ensure the athlete can safely return to exercise following the heat illness.

The influence of heat on the occurrence of exercise associated muscle cramps: a review

Article

Full-text available

Mar 2017

The occurrence of exercise associated muscle cramps can be detrimental for exercise performance and there is controversy about its relation to exercise in the heat. The purpose of this study is therefore to review the influence of exercising in the heat on the occurrence of cramps. There are three main theories for the development of cramps during exercise: dehydration, electrolyte depletion and altered neuromuscular control. Muscle cramps can be divided into two categories: fatigue-induced and heat-related. Fatigue-induced cramps can be explained by solely muscle fatigue which causes reduced neuromuscular control. Heat-related cramps are a result of muscle fatigue combined with fluid and electrolyte loss due to sweating. Heat results in more muscle fatigue and therefore an altered neuromuscular control. Moreover, heat will result in a higher sweat rate and sweat sodium concentration. Taken together, these heat-associated adaptations are likely to influence the occurrence of both fatigue-induced and heat-related muscle cramps.

Acute Medical Problems in the Adolescent Tennis Player

Chapter

Apr 2016

Deena C. Casiero

Although all types of acute medical problems of all types can occur in adolescent tennis players, the specific demands of the sport can predispose young athletes to certain acute medical conditions such as fluid disorders and exertional heat illness. In addition, while athletes are participating in this physically demanding sport, otherwise silent underlying cardiovascular issues can be unveiled. Concussions, though not common in the sport of tennis, can occur in any athlete and are one of the most important medical issues concerning adolescent athletes today. The purpose of this chapter is to familiarize the health-care provider with several acute medical problems that may occur in young tennis athletes and to discuss how improving diagnosis, management, and prevention of these conditions can lead to not only better performance but better overall health and wellness.

Sports Injuries

Article

Jan 2015

Johannes Zwerver

Regular participation in sports and exercise activities is considered beneficial for health but unfortunately sometimes sports injuries occur. Based on the onset of symptoms and the mechanism, sports injuries can be classified as either acute injuries (due to a single traumatic event) or overuse injuries (due to repetitive microtraumata). In this chapter, the various types and causes of sports injuries of the musculoskeletal system are described. The general principles of acute and overuse injuries of the bone, cartilage, joint, ligaments, muscle, tendon, bursa, and nerves are discussed, and some insight into etiology and pathophysiology is provided.

Heat Cramps: Treatment and Prevention

Article

Sep 2010

Assessment Of Physiological Attributes Leading To Distance-Running Performance Of Trained Collegiate Distance-Runners

Article

Sep 2011

Mike Martino

Purpose - This study sought to determine the relationship among running economy (RE), anaerobic threshold (AT), maximal aerobic capacity (VO2max), ventilatory threshold (VT) and distance-running performance in collegiate distance-runners. Methods - Fourteen (7 male, 7 female) well-trained, collegiate distance-runners were tested during treadmill running at progressively increasing velocities (190 m×min-1 – 290 m×min-1) to determine RE, AT and VT on one occasion, and VO2max was measured on a second occasion. Distance-running performance was assessed as the time to complete the NCAA Division II South-eastern Regional cross-country championship race (10-km for men, 6-km for women), and was normalized to distance to yield running pace velocity. Results - Performance pace velocity and RE were not strongly related across the 3 common economy velocities of 230, 240, and 250 m×min-1 (r2 = 0.01, 0.31, and 0.35 respectively, p < 0.05). Running pace at AT was a very strong predictor (r2 = 0.95, p < 0.05) of performance pace velocity, and so was pace at VT (r2 = 0.87, p < 0.05). VO2max was a strong predictor of performance pace (r2 = 0.88, p < 0.05), but only when the men and women were compared together. Conclusions - Running pace at AT accounted for 95% of the variation observed in race performance, confirming that among trained distance-runners, pace at AT was the strongest predictor of performance.

Muscle Cramps in Old Adults: Clinical Features and Pathophysiology

Article

Full-text available

Dec 2013

Muscle cramps are defined as painful, spasmodic, involuntary skeletal muscle contractions during or immediately after physical exercise. Muscle cramps have a typical clinical presentation, as the definition and the diagnosis is made based on a typical history together with the findings on clinical examination. Muscle cramps are self-extinguishing within seconds to minutes or relieved by stretching, and is often accompanied by a palpable knotting of the muscle. Old adults are prone to get muscle cramps, which may occur in patients with diseases, but also occur often in healthy subjects with no history of nervous system or metabolic disorders. Comorbidity and multiple medications, including diuretics due to an underlying disease, can be a part of the reason in old adults. We reviewed articles regarding the etiology of muscle cramps and introduced a new hypothesis of 'altered neuromuscular control', which has been documented recently.

The Relationship Among Running Economy, Lactate Threshold and Distance Running Performance

Article

Full-text available

Dec 2011

Christopher D. Black

Plasma potassium concentration and content changes following banana ingestion in exercised males

Article

Full-text available

Dec 2012

Kevin Miller

Risk Factors for Exercise Associated Muscle Cramping (Eamc) in Marathon Runners 993

Article

Full-text available

May 1996

The elite marathon runner: problems during and after competition

Article

Full-text available

Apr 1988

Two questionnaires were given to the participants of the Danish national marathon championship to obtain information on health, training habits, previous injuries and the medical problems sustained during and after the competition. All 60 participants replied to both questionnaires. The elite runner is training between 90-150 km per week, using one daily training session. He is generally careful about stretching and warming up and down. Forty-three per cent of runners sustained injuries in the last year that prevented them from training, but only 3% needed to stay off work. The most common reasons for not completing the race were exhaustion and injuries to the lower extremities. Sixty-one per cent of the runners who did not drink at all refreshment stations dropped out, whereas only 27% of those who did dropped out. There was no difference in relation to results or medical problems between the group who used a special diet before the run and those who did not. The major medical problems were gastrointestinal disturbances, skin lesions and pain or cramps in the lower extremities. No serious injuries were reported.

Aetiology of skeletal muscle ‘cramps’ during exercise: A novel hypothesis

Article

Full-text available

Jul 1997

The aetiology of exercise-associated muscle cramps (EAMC), defined as 'painful, spasmodic, involuntary contractions of skeletal muscle during or immediately after physical exercise', has not been well investigated and is therefore not well understood. This review focuses on the physiological basis for skeletal muscle relaxation, a historical perspective and analysis of the commonly postulated causes of EAMC, and known facts about EAMC from recent clinical studies. Historically, the causes of EAMC have been proposed as (1) inherited abnormalities of substrate metabolism ('metabolic theory') (2) abnormalities of fluid balance ('dehydration theory'), (3) abnormalities of serum electrolyte concentrations ('electrolyte theory') and (4) extreme environmental conditions of heat or cold ('environmental theory'). Detailed analyses of the available scientific literature including data from recent studies do not support these hypothesis for the causes of EAMC. In a recent study, electromyographic (EMG) data obtained from runners during EAMC revealed that baseline activity is increased (between spasms of cramping) and that a reduction in the baseline EMG activity correlates well with clinical recovery. Furthermore, during acute EAMC the EMG activity is high, and passive stretching is effective in reducing EMG activity. This relieves the cramp probably by invoking the inverse stretch reflex. In two animal studies, abnormal reflex activity of the muscle spindle (increased activity) and the Golgi tendon organ (decreased activity) has been observed in fatigued muscle. We hypothesize that EAMC is caused by sustained abnormal spinal reflex activity which appears to be secondary to muscle fatigue. Local muscle fatigue is therefore responsible for increased muscle spindle afferent and decreased Golgi tendon organ afferent activity. Muscles which cross two joints can more easily be placed in shortened positions during exercise and would therefore decrease the Golgi tendon organ afferent activity. In addition, sustained abnormal reflex activity would explain increased baseline EMG activity between acute bouts of cramping. Finally, passive stretching invokes afferent activity from the Golgi tendon organ, thereby relieving the cramp and decreasing EMG activity.

Serum electrolyte concentrations and hydration status are not associated with exercise associated muscle cramping (EAMC) in distance runners

Article

Full-text available

Sep 2004
BRIT J SPORT MED

To determine whether acute exercise associated muscle cramping (EAMC) in distance runners is related to changes in serum electrolyte concentrations and hydration status. A cohort of 72 runners participating in an ultra-distance road race was followed up for the development of EAMC. All subjects were weighed before and immediately after the race. Blood samples were taken before the race, immediately after the race, and 60 minutes after the race. Blood samples were analysed for glucose, protein, sodium, potassium, calcium, and magnesium concentrations, as well as serum osmolality, haemoglobin, and packed cell volume. Runners who suffered from acute EAMC during the race formed the cramp group (cramp, n = 21), while runners with no history of EAMC during the race formed the control group (control, n = 22). There were no significant differences between the two groups for pre-race or post-race body weight, per cent change in body weight, blood volume, plasma volume, or red cell volume. The immediate post-race serum sodium concentration was significantly lower (p = 0.004) in the cramp group (mean (SD), 139.8 (3.1) mmol/l) than in the control group (142.3 (2.1) mmol/l). The immediate post-race serum magnesium concentration was significantly higher (p = 0.03) in the cramp group (0.73 (0.06) mmol/l) than in the control group (0.67 (0.08) mmol/l). There are no clinically significant alterations in serum electrolyte concentrations and there is no alteration in hydration status in runners with EAMC participating in an ultra-distance race.

Influence of Hydration and Electrolyte Supplementation on Incidence and Time to Onset of Exercise-Associated Muscle Cramps

Article

Full-text available

Jul 2005
J ATHL TRAINING

Context: Exercise-associated muscle cramps (EAMCs) are common among physically active individuals and are temporarily disabling; therefore, prevention is of great interest.Objective: To determine the role of hydration and electrolyte supplementation in the prevention of EAMCs.Design: Each subject completed 2 counterbalanced trials in a repeated-measures design.Setting: University of Alabama.Patients or Other Participants: College-aged men (n = 13) with a history of EAMCs.Intervention(s): In each trial, participants performed a calf-fatiguing protocol to induce EAMCs in the calf muscle group. Each trial was performed in a hot environment (dry bulb temperature of 37 degrees C, relative humidity of 60%). In the carbohydrate-electrolyte trial, subjects consumed, at a rate similar to sweat loss, a carbohydrate-electrolyte beverage with sodium chloride added. In the hypohydration trial, subjects were not allowed to consume any fluids.Main Outcome Measure(s): We measured the incidence and time to onset of EAMCs.Results: Nine participants experienced cramps in the carbohydrate-electrolyte trial, compared with 7 in the hypohydration trial. Of the 7 individuals who had EAMCs in both trials, exercise duration before onset was more than doubled in the carbohydrate-electrolyte trial (36.8 +/- 17.3 minutes) compared with the hypohydration trial (14.6 +/- 5.0 minutes, P < .01).Conclusions: Consumption of a carbohydrate-electrolyte beverage before and during exercise in a hot environment may delay the onset of EAMCs, thereby allowing participants to exercise longer. However, it appears that dehydration and electrolyte loss are not the sole causes of EAMCs, because 69% of the subjects experienced EAMCs when they were hydrated and supplemented with electrolytes.

Sweat and Sodium Losses in NCAA Football Players: A Precursor to Heat Cramps?

Article

Full-text available

Jan 2006

This observational study was designed to determine whether football players with a history of heat cramps have elevated fluid and sodium losses during training. During a "two-a-day" training camp, five Division I collegiate football players (20.2 +/- 1.6 y, 113 +/- 20 kg) with history of heat cramps (C) were matched (weight, age, race and position) with a cohort of teammates (19.6 +/- 0.6 y, 110 +/- 20 kg) who had never cramped (NC). Change in body weight (adjusted by fluid intake) determined gross sweat loss. Sweat samples (forearm patch) were analyzed for sodium and potassium concentrations. Ad libitum fluid intake was measured by recording pre- and post-practice bottle weights. Average sweat sodium loss for a 2.5-h practice was projected at 5.1 +/- 2.3 g (C) vs. 2.2 +/- 1.7 g (NC). When averaged across two practices within the day, fluid intake was similar between groups (C: 2.6 +/- 0.8 L vs. NC: 2.8 +/- 0.7 L), as was gross sweat loss (C: 4.0 +/- 1.1 L vs. NC: 3.5 +/- 1.6 L). There was wide variability in the fluid deficit incurred for both C and NC (1.3 +/- 0.9 vs. 0.7 +/- 1.2%) due to fluid intake. Sweat potassium was similar between groups, but sweat sodium was two times higher in C versus NC (54.6 +/- 16.2 vs. 25.3 +/- 10.0 mmol/L). These data indicate that sweat sodium losses were comparatively larger in cramp-prone football players than in NC. Although both groups consumed sodium-containing fluids (on-field) and food (off-field), both appeared to experience an acute sodium deficit at the end of practices based on sweat sodium losses. Large acute sodium and fluid losses (in sweat) may be characteristic of football players with a history of heat cramping.

Exertional Heat Illness and Environmental Conditions During a Single Football Season in the Southeast

Article

Full-text available

Jul 2006

Context: Recommendations for heat illness prevention provided by sports medicine associations do not always account for sex differences, specific age populations, regional environmental conditions, equipment worn during activity, or the athlete's size or preexisting level of fitness. Objective: To evaluate the rate of exertional heat illness (EHI) among collegiate football athletes and to monitor environmental conditions during American football practice for a 3-month period. Design: Epidemiologic study in which we reviewed the occurrence rates of EHI and wet bulb globe temperature readings during a 3-month period of American collegiate football practice sessions. Setting: Five universities in the southeastern region of the United States. Patients or other participants: Collegiate football players at the 5 universities. Main outcome measure(s): Wet bulb globe temperatures were recorded from August through October 2003, at the beginning, middle, and end of each practice session. The EHIs were identified and recorded, and athlete-exposures (AEs) were calculated. Results: A total of 139 EHIs and 33 196 AEs were reported (EHI rate = 4.19/1000 AEs). The highest incidence of EHIs was in August (88%, EHI rate = 8.95/1000 AEs) and consisted of 70% heat cramps (6.13/1000 AEs), 23% heat exhaustion (2.06/ 1000 AEs), and 7% heat syncope (0.58/1000 AEs). No cases of heat stroke or hyponatremia were identified. The highest risk of EHI occurred during the first 3 weeks of the study; mean wet bulb globe temperature declined significantly as the study continued ( P < .001). Temperatures in the final 5 weeks of the study were significantly cooler than in the first 5 weeks ( P < .05). Conclusions: Heat cramps were the most common EHI and occurred most often during the first 3 weeks of practice. Athletic trainers should take all necessary preventive measures to reduce the risk of EHI.

American College of Sports Medicine position stand. Exercise and Fluid Replacement

Article

Full-text available

Feb 2007

This Position Stand provides guidance on fluid replacement to sustain appropriate hydration of individuals performing physical activity. The goal of prehydrating is to start the activity euhydrated and with normal plasma electrolyte levels. Prehydrating with beverages, in addition to normal meals and fluid intake, should be initiated when needed at least several hours before the activity to enable fluid absorption and allow urine output to return to normal levels. The goal of drinking during exercise is to prevent excessive (>2% body weight loss from water deficit) dehydration and excessive changes in electrolyte balance to avert compromised performance. Because there is considerable variability in sweating rates and sweat electrolyte content between individuals, customized fluid replacement programs are recommended. Individual sweat rates can be estimated by measuring body weight before and after exercise. During exercise, consuming beverages containing electrolytes and carbohydrates can provide benefits over water alone under certain circumstances. After exercise, the goal is to replace any fluid electrolyte deficit. The speed with which rehydration is needed and the magnitude of fluid electrolyte deficits will determine if an aggressive replacement program is merited.

Muscle Cramping in the Marathon

Article

Apr 2007

Martin Schwellnus

Skeletal muscle cramps are commonly encountered in marathon runners by medical staff. However, the aetiology, and therefore management, of this condition is not well understood. Exercise-associated muscle cramping (EAMC) is defined as an involuntary, painful contraction of skeletal muscle during or immediately after exercise. In early anecdotal reports, cramps were associated with profuse sweating, together with changes in serum electrolyte concentrations. No mechanism explains how such imbalances in serum electrolytes result in localised muscle cramping. The ‘muscle fatigue’ hypothesis suggests that EAMC is the result of an abnormality of neuromuscular control at the spinal level in response to fatiguing exercise and is based on evidence from epidemiological studies, animal experimental data on spinal reflex activity during fatigue and electromyogram data recorded during bouts of acute cramping after fatiguing exercise. The development of premature muscle fatigue appears to explain the onset of EAMC.

SALINE DRINK IN INDUSTRIAL FATIGUE

Article

Jan 1925

R OSWALD

620 CRAMPING STUDIES IN 2600 ENDURANCE ATHLETES

Article

Apr 1990

Exertional Heat Illness during Training and Competition

Article

Mar 2007

Exertional heat illness can affect athletes during high-intensity or longduration exercise and result in withdrawal from activity or collapse during or soon after activity. These maladies include exercise associated muscle cramping, heat exhaustion, or exertional heatstroke. While certain individuals are more prone to collapse from exhaustion in the heat (i.e., not acclimatized, using certain medications, dehydrated, or recently ill), exertional heatstroke (EHS) can affect seemingly healthy athletes even when the environment is relatively cool. EHS is defined as a rectal temperature greater than 40-C accompanied by symptoms or signs of organ system failure, most frequently central nervous system dysfunction. Early recognition and rapid cooling can reduce both the morbidity and mortality associated with EHS. The clinical changes associated with EHS can be subtle and easy to miss if coaches, medical personnel, and athletes do not maintain a high level of awareness and monitor at-risk athletes closely. Fatigue and exhaustion during exercise occur more rapidly as heat stress increases and are the most common causes of withdrawal from activity in hot conditions. When athletes collapse from exhaustion in hot conditions, the term heat exhaustion is often applied. In some cases, rectal temperature is the only discernable difference between severe heat exhaustion and EHS in on-site evaluations. Heat exhaustion will generally resolve with symptomatic care and oral fluid support. Exercise associated muscle cramping can occur with exhaustive work in any temperature range, but appears to be more prevalent in hot and humid conditions. Muscle cramping usually responds to rest and replacement of fluid and salt (sodium). Prevention strategies are essential to reducing the incidence of EHS, heat exhaustion, and exercise associated muscle cramping.

How to Read a Paper: The Basics of Evidence-based Medicine

Book

Jan 2006

Skeletal Muscle Cramps During Exercise

Article

Nov 1999

Martin Schwellnus

Cramps are painful, involuntary contractions of skeletal muscle that occur during or immediately after exercise and are common in endurance athletes. Although cramps can occur in many rare medical conditions, most athletes who have exercise-associated muscle cramping do not have congenital or acquired medical disorders. The cause of cramping is not well understood but may have to do with abnormal spinal control of motor neuron activity, particularly when a muscle contracts in a shortened position. Important risk factors include muscle fatigue and poor stretching habits. Treatment consists mainly of passive stretching, with supportive measures as needed. Special diagnostic studies and conditioning programs may be necessary for recurrent episodes.

Medical care at ultraendurance triathlons

Article

Nov 1989

Robert H. Laird

With the increasing participation in triathlons of all distances has come a corresponding increase in the need for competent medical information relating to the care of these triathletes. Although medical organization at triathlons involves certain principles which should be applied regardless of race specifics, there are certain other arrangements that will vary with the size and length of the event. For example, the longer races require a reliable communication system, fully equipped mobile response teams, and a larger number of medical staff. Medical communication needs can be served by having priority medical transmissions via UHF radio from mobile vans to a main medical station. An average of 2.5 physicians and 7.5 nurses and other paramedical volunteers for each group of 100 competitors has been found to be sufficient to meet the medical needs of triathletes. The swim, although having the greatest potential for catastrophe, accounts for only 1-3% of medical visits at the Hawaii Ironman Triathlon. Ten percent of injuries requiring medical evaluation at the Hawaii Ironman occur during the bike portion of the race. The rest occur either during the run or after finishing. Seventy-one percent of the total medical visits come directly from the finish line. Dehydration and exhaustion account for the majority of primary medical diagnoses. Appropriate medical care at triathlon races is necessary to aid athletes in safely experiencing their physical potentials.

Is this really a muscle cramp?

Article

Oct 1989

John M. Eaton

Preview In this article, Dr Eaton aids physicians in the differential diagnosis of muscle cramps and conditions that mimic cramps. He also explains the difference between idiopathic cramps and cramps caused by systemic disorders that respond to specific treatment. Finally, he proposes a plan for evaluating and treating patients who complain of muscle cramps.

Medical Problems in Mass Participation Runs

Article

Dec 1988

John W. Robertson

Road race medicine has evolved rapidly over the last few years from minimal, if any, on-course coverage to efficient well-organised medical teams. As the number of casualties is fairly predictable and varies directly with climatic heat stress, road races can plan for adequate medical coverage based on the expected number of entrants. The number of casualties can be reduced dramatically by promoting public awareness of safe running techniques and identifying the runner at risk before injury occurs. Runners with heat injuries must be identified rapidly and treated aggressively which requires on-site emergency vehicles dispatched by an efficient communications network.

Dynamic and static stretch responses in muscle spindle receptors in fatigued muscle

Article

Sep 1985

Dynamic and static stretch responses in muscle spindles were investigated in fatigued muscle to determine if acute adaptations do occur in receptor discharge as has been shown after contractions of short duration. Fatigue to 60-50% maximum tetanic tension was induced in the isolated gastrocnemius muscle in 16 cats by sustained, 7 X threshold electrical stimulation (100 Hz) of the cut L7 ventral root and S1 ventral root. Group Ia and II afferent fiber responses to slow ramp stretches (5 mm X s-1) and vibration (100 Hz) applied to the Achilles tendon were monitored before and immediately after muscle tetany to fatigue. Changes in firing characteristics were similar when results from faster (25-30 mm X s-1) ramp stretches were contrasted. During muscle fatigue, decreases in response latency to displacement and increases in resting discharge, mean frequency during stretch, and frequency of firing to vibration were predominant in both afferent fiber types. Static responses were generally lower, indicating a decrease in position sensitivity. Resting muscle force and passive peak muscle stiffness were consistently higher following contraction. The sum effects of these proprioceptive afferent and mechanical muscle responses would be to increase muscle stiffness and thus resist yield in muscle length to perturbations at lower muscle forces. The magnitude of these adaptations in proprioceptive discharge appears dependent on intrafusal muscle fiber activation.

The cause of leg cramps and knee pains: an hypothesis and effective treatment

Article

Feb 1988
MED HYPOTHESES

Cramps and pains of the lower extremities along with stiffness and pains in the knees are common complaints in the general population. Because the etiology and development of these disorders are poorly understood, treatment has been haphazard, for the most part unsuccessful, and occasionally dangerous. The diagnosis of "arthritis" is often incorrect; when osteoarthritis is present it is frequently not the cause of the pain. We name these maladies the "stiff leg syndrome" and hypothesise that they are caused by muscle and tendon shortening which came about as a direct result of modern civilization; the popular practice of squatting close to the ground to defecate, cook and eat was replaced by a more "civilized" practice of sitting high on toilets and chairs. We discuss several simple stretching exercises which mimic the effects of squatting and frequently result in immediate and dramatic relief of symptoms.

Medical and physiological considerations in triathlons

Article

Mar 1987
AM J SPORT MED

Triathlons (races involving consecutive swimming, bi cycling, and running) have become commonplace in the United States. These races may involve from 30 min utes to 36 hours of continuous exercise, usually in warm or hot environments. Little has been published regarding the medical and physiological aspects of these events. This paper represents the first large study to date on the subject, including both an analysis of medical complications at six triathlons as well as a prospective electrolyte study conducted at two of these races. Medical records were kept and examined for all ath letes requiring treatment during a typical United States Triathlon Series (USTS) race in 1986 (1,000 starters; finish times, 2 to 4 hours), a typical Ironman Qualifier (IQ) race in 1986 (622 starters; finish times, 4 to 8 hours), and the 1982 through 1985 Hawaii lronman World Championships (4,583 starters; finish times, 9 to 17 hours). At the USTS race, fewer than 2% (17/1,000) of the starters required aid, at the IQ, approximately 10% (61 /622) of the starters were treated, and at the Ironman, an average of 17% (794/4,583) received med ical attention. The most common diagnoses at the USTS and IQ were dehydration and heat exhaustion. At the lronman, dehydration and heat problems were complicated by hyponatremia. Because hyponatremia has been reported as a com plication of ultraendurance events, a prospective study was performed on 36 athletes during a USTS race and 64 athletes at the 1984 lronman race. Prerace and postrace blood samples showed that no athletes were hyponatremic following the shorter USTS race, but 27% (17/64) of the athletes studied were hyponatremic fol lowing the lronman race. Medical personnel should be prepared to treat a minimum of 2% and up to 10% of the athletes in races lasting up to 4 hours, 10% to 20% of those in races lasting 4 to 8 hours, and at least 20% of starters in races lasting between 9 and 17 hours. For races less than 4 hours, the IV fluid of choice should be D5 1/2 NSS (normal saline solution). For races longer than 4 hours, D5NSS should be used for IV resuscitation.

Exercise‐induced muscle cramp: A prospective biochemical study in marathon runners

Article

Feb 1986

R J Maughan

Exercise-induced muscle cramp has been considered to result from disturbances of fluid and electrolyte balance resulting from excessive sweat loss. Serum biochemical and haematological measurements were made on 82 male marathon runners before and after a 42.2-km race. Fifteen (18%) of the runners reported an attack of muscle cramp which occurred after 35 +/- 6 km (mean +/- S.D.) had been covered. These subjects were not different from the others in terms of racing performance or training status. Serum electrolyte concentrations, including sodium and potassium, were not different between those suffering from cramp and those not so affected either before or after the race, although a significant (P less than 0.001) increase in serum sodium concentrations occurred in both groups. Serum bicarbonate concentrations fell to the same extent (from 28 to 24 mmol l-1) in both groups. Significant decreases in plasma volume, calculated from the changes in circulating haemoglobin and haematocrit, occurred in both groups of subjects, but there was no difference in the extent of the haemoconcentration. The results suggest that exercise-induced muscle cramp may not be associated with gross disturbances of fluid and electrolyte balance.

Physiotherapy and electromyography in muscle cramp

Article

Jan 1986

P Helin

Four cases of muscle cramps, at a sports institute, are presented. Electric activity was increased in cramp due to overload. The influence of stretching, electro- and compression therapies on these increased Electromyographic (EMG) activities was studied. The registration was performed with an EMG-analyser combined with a recorder, using surface electrodes.

Stretch sensitivity of Golgi tendon organs in fatigued gastrocnemius muscle

Article

Mar 1986

Alterations in Golgi tendon organs' (Ib afferent receptors) stretch sensitivity were assessed in fatigued gastrocnemius muscle of cats. Muscle fatigue to 60-50% peak tension was induced in 13 cats by electrical stimulation of L7 and S1 ventral roots. Forty-three group Ib afferent fibers were recorded in L7 or S1 dorsal root filaments before and during fatigue. Fiber activity was assessed by applying to the Achilles tendon a 5-mm ramp stretch at 5 or 25-30 mm X s-1. Group Ib afferent responses to both velocities of stretch were either completely abolished or depressed over several seconds compared to pre-fatigue firing frequencies. When responding, longer latencies (measured at 5 mm X s-1 only) to firing onset occurred during fatigue. Increasing the rate of stretch (250 mm X s-1) to produce a 5-mm stretch approximately equivalent to twitch tension time revealed a depression more selective to static stretch sensitivity. Post-excitation depression of the Ib receptor potential appears to be one possible mechanism. These acute adaptations in Ib afferent discharge to muscle stretch were opposite in direction to those recently reported in fatigued muscle for group Ia and group II muscle spindle afferents. Functional implications of these results are discussed.

The influence of muscle lengthening on cramps

Article

Feb 1993

Muscle cramps induced by voluntary contraction and by electrical stimulation of the peripheral nerve were studied electrophysiologically in 10 healthy subjects. The aim was to verify that cramps can be evoked by electrical stimulation of peripheral nerve and to clarify the physiological mechanism responsible by analyzing the effect of muscular stretching on cramps. Our results showed: (1) Cramps can be induced even after peripheral nerve block by electrical stimulation distal to the block. (2) No cramps were recorded during or following maximal voluntary contraction without muscular shortening, while 7 of 10 subjects showed a true cramp following maximal effort with shortening of the muscle. (3) Muscle stretching caused a sudden interruption of cramps induced by either voluntary contraction or electrical stimulation of the peripheral nerve, even after the induction of nerve block. (4) The lengthening state of the muscle can strongly influence the possibility of evoking cramps by electrical stimulation of nerve. Our study verifies the experimental model proposed by Lambert in 1969, emphasizing the relevance of frequency of stimulation and confirming the hypothesis that cramps are of peripheral origin. The effects of muscle stretch and lengthening on cramp interruption and development also have a peripheral mechanism.

Heat Cramps during Tennis: A Case Report

Article

Apr 1996
Int J Sport Nutr

Michael F. Bergeron

A 17-year-old, nationally ranked, male tennis player (AH) had been experiencing heat cramps during tennis match play. His medical history and previous physical exams were unremarkable, and his in-office blood chemistry profiles were normal. On-court evaluation and an analysis of a 3-day dietary record revealed that AH's sweat rate was extensive (2.5 L.hr-1) and that his potential daily on-court sweat sodium losses (89.8 mmol.hr of play-1) could readily exceed his average daily intake of sodium (87.0-174.0 mmol.day-1). The combined effects of excessive and repeated fluid and sodium losses likely predisposed AH to heat cramps during play. AH was ultimately able to eliminate heat cramps during competition and training by increasing his daily dietary intake of sodium.

Muscular cramps: Proposals for a new classification

Article

Apr 2003

Muscle cramps are involuntary, painful, sudden contractions of the skeletal muscles. They are present in normal subjects under certain conditions (during a strong voluntary contraction, sleep, sports, pregnancy) and in several pathologies such as myopathies, neuropathies, motoneuron diseases, metabolic disorders, hydroelectrolyte imbalances or endocrine pathologies. There has been considerable uncertainty in the literature regarding the classification and nomenclature of muscle cramps, both because the term "cramp" is used to indicate a variety of clinical features of muscles, leading to its use as an imprecise "umbrella" term that includes stiffness, contractures and local pain, and because the spectrum of the diseases in which it appears is wide. The purpose of the present study is to propose a simple classification to provide a framework to better recognize the full spectrum of phenomenology of muscle cramps.

Heat cramps: Fluid and electrolyte challenges during tennis in the heat

Article

Apr 2003
J SCI MED SPORT

Michael F. Bergeron

Sweat losses during tennis can be considerable. And while most players make a genuine effort to stay well hydrated to maintain performance and reduce the risk of heat illness, regular and copious water intake is often not enough. Besides an extraordinary water loss, extensive sweating can lead to a concomitant large electrolyte deficit too--particularly for sodium. Although a variety of other mineral deficiencies and physiological conditions are purported to cause muscle cramps, evidence suggests that, when a tennis player cramps in warm to hot weather, extensive and repeated sweating during the current and previous matches and a consequent sodium deficit are usually the primary contributing factors. Heat cramps often begin as subtle "twitches" or fasciculations in one or more voluntary muscles and, unless treated, can rapidly progress to widespread debilitating muscle spasms that leave an afflicted player on the court writhing in pain. If sufficient preventive measures are taken well before and during play, such cramping is avoidable in most cases. Appropriate and sufficient salt and fluid intake will enhance rehydration and fluid distribution throughout a player's body, so that heat cramps can be completely averted, even during long matches in the most challenging environments.

An electromyographic study of induced and spontaneous muscle cramps

Article

Mar 1957
Electroencephalogr Clin Neurophysiol

Serum Electrolytes in Ironman Triathletes with Exercise-Associated Muscle Cramping

Article

Aug 2005

To compare serum electrolyte concentrations of cramping and control Ironman triathletes. Triathletes suffering from acute exercise-associated muscle cramping (EAMC) after the 2000 South African Ironman Triathlon formed the cramping group (CR, N = 11). Non-cramping triathletes matched for race finishing time and body mass formed the control group (CON, N = 9). All subjects were weighed at race start and immediately post-race. Blood samples were drawn from both groups during recovery for the analysis of serum magnesium, glucose, sodium, potassium and chloride concentrations. Hemoglobin concentration and hematocrit were also measured. Surface electromyography (EMG) (mV) was recorded from a non-cramping control muscle (triceps) and the most severely cramping lower limb muscle of the CR group. EMG was recorded at the beginning of every minute for a 10-min period during recovery. There were no significant differences between the groups for body mass or percent body mass loss during the race. Post-race sodium concentration was significantly lower (P = 0.01) in the CR group than the CON group (140 +/- 2 vs 143 +/- 3 mmol.L) but was within the normal clinical range of post-race serum sodium concentrations. There were no significant differences between the two groups for post-race serum electrolytes, glucose, hemoglobin concentrations or hematocrit. Surface EMG (mV) was significantly higher (P < 0.05) in the cramping muscles than the control muscle of the CR group at 0, 3, 4, and 5 min of the 10-min recording period. Acute EAMC in ironman triathletes is not associated with a greater percent body mass loss or clinically significant differences in serum electrolyte concentrations. The increased EMG activity of cramping muscles may reflect increased neuromuscular activity.

Level of Evidence in Orthopaedic Journals

Article

Dec 2005

The American edition of The Journal of Bone and Joint Surgery (JBJS-A) has included a level-of-evidence rating for each of its clinical scientific papers published since January 2003. The purpose of this study was to assess the type and level of evidence found in nine different orthopaedic journals by applying this level-of-evidence rating system. We reviewed all clinical articles published from January through June 2003 in nine orthopaedic journals. Studies of animals, studies of cadavera, basic-science articles, review articles, case reports, and expert opinions were excluded. The remaining 382 clinical articles were randomly assigned to three experienced reviewers and two inexperienced reviewers, who rated them with the JBJS-A grading system. Each reviewer determined whether the studies were therapeutic, prognostic, diagnostic, or economic, and each rated the level of evidence as I, II, III, or IV. Reviewers were blinded to the grades assigned by the other reviewers. According to the reviewers' ratings, 70.7% of the articles were therapeutic, 19.9% were prognostic, 8.9% were diagnostic, and 0.5% were economic. The reviewers graded 11.3% as Level I, 20.7% as Level II, 9.9% as Level III, and 58.1% as Level IV. The kappa values for the interobserver agreement between the experienced reviewers and the inexperienced reviewers were 0.62 for the level of evidence and 0.76 for the study type. The kappa values for the interobserver agreement between the experienced reviewers were 0.75 for the level of evidence and 0.85 for the study type. The kappa values for the agreement between the reviewers' grades and the JBJS-A grades were 0.84 for the level of evidence and 1.00 for the study type. All kappa values were significantly different from zero (p < 0.0001 for all). The percentage of articles that were rated Level I or II increased in accordance with the 2003 journal impact factors for the individual journals (p = 0.0061). Orthopaedic journals with a higher impact factor are more likely to publish Level-I or II articles. The type and level of information in orthopaedic journals can be reliably classified, and clinical investigators should pursue studies with a higher level of evidence whenever feasible.

Heat cramps. A clinical and chemical study

Article

Jun 1933

Evidence-Based Approach to Lingering Hydration Questions

Article

Feb 2007

Studies related to fundamental hydration issues have required clinicians to re-examine certain practices and concepts. The ingestion of substances such as creatine, caffeine, and glycerol has been questioned in regards to safety and hydration status. Reports of overdrinking (hyponatremia) also have brought into question the practices of drinking appropriate fluid amounts and the role that fluid-electrolyte balance has in the etiology of heat illnesses such as heat cramps. This article offers a fresh perspective on timely topics related to hydration, fluid balance, and exercise in the heat.

Muscle cramping in the marathon: Aetiology and risk factors

Article

Feb 2007

Martin Schwellnus

Skeletal muscle cramps are commonly encountered in marathon runners by medical staff. However, the aetiology, and therefore management, of this condition is not well understood. Exercise-associated muscle cramping (EAMC) is defined as an involuntary, painful contraction of skeletal muscle during or immediately after exercise. In early anecdotal reports, cramps were associated with profuse sweating, together with changes in serum electrolyte concentrations. No mechanism explains how such imbalances in serum electrolytes result in localised muscle cramping. The 'muscle fatigue' hypothesis suggests that EAMC is the result of an abnormality of neuromuscular control at the spinal level in response to fatiguing exercise and is based on evidence from epidemiological studies, animal experimental data on spinal reflex activity during fatigue and electromyogram data recorded during bouts of acute cramping after fatiguing exercise. The development of premature muscle fatigue appears to explain the onset of EAMC.

A survey of Exercise Associated Muscle Cramps (EAMC) in rugby players. BSc (Med) (Hons) dissertation. Cape Town: University of Cape Town

Jan 2001

R Tindall

Tindall R. A survey of Exercise Associated Muscle Cramps (EAMC) in rugby players. BSc (Med) (Hons) dissertation. Cape Town: University of Cape Town; 2001.

Muscle cramps in athletes, BSc (Med) (Hons) Sports Medicine dissertation. Cape Town: University of Cape Town

Jan 1991

S I Manjra

Manjra SI. Muscle cramps in athletes, BSc (Med) (Hons) Sports Medicine dissertation. Cape Town: University of Cape Town; 1991.

Die voorkoms van spierkrampe in fietsryers MPrax Med dissertation. Univer-sity of the Free State

Jan 1994

C Grundling

Grundling C. Die voorkoms van spierkrampe in fietsryers. MPrax Med dissertation. Univer-sity of the Free State; 1994.

New disorder from heat: a disorder due to exposure to intense heat

Jan 1908
1969

Edsall

Edsall DL. New disorder from heat: a disorder due to exposure to intense heat. JAMA 1908;11:1969-71.

Exercise and fluid replacement. ACSM position stand

Jan 2007
377-90

Sawka
Burke Lm Mn
Er Eichner

Sawka MN, Burke LM, Eichner ER, et al. Exercise and fluid replacement. ACSM position stand. Med Sci Sports Exerc 2007;39(2):377–90.

Exercise associated muscle cramping: investigating a novel hypothesis. MSc (Med) dissertation. Cape Town: University of Cape Town

Jan 2003

N U Sulzer

Sulzer NU. Exercise associated muscle cramping: investigating a novel hypothesis. MSc (Med) dissertation. Cape Town: University of Cape Town; 2003.

Exercise Associated Muscle Cramps (EAMC) in Triathletes. MPhil (Sports Medicine) dissertation. Cape Town: University of Cape Town

Jan 2006

N Drew

Drew N. Exercise Associated Muscle Cramps (EAMC) in Triathletes. MPhil (Sports Medicine) dissertation. Cape Town: University of Cape Town; 2006.

Exercise-associated muscle cramps in distance runners: the role of serum electrolytes both during and following an ultra-marathon and IEMG activity in the recovery phase postcramp. MPhil (Sports Medicine) dissertation. Cape Town: University of Cape Town

Jan 1996

J Nicol

Nicol J. Exercise-associated muscle cramps in distance runners: the role of serum electrolytes both during and following an ultra-marathon and IEMG activity in the recovery phase postcramp. MPhil (Sports Medicine) dissertation. Cape Town: University of Cape Town; 1996.

MPrax Med dissertation. University of the Free State

Jan 1994

C Grundling

Grundling C. Die voorkoms van spierkrampe in fietsryers. MPrax Med dissertation. University of the Free State; 1994.

Exercise and fluid replacement. ACSM position stand

Jan 2007
377

Sawka

Muscle Cramping in Athletes-Risk Factors, Clinical Assessment, and Management

Abstract

No full-text available

Recommended publications

Effect of the flexibility training performed immediately before resistance training on muscle hypert...

Effects of a Short Proprioceptive Neuromuscular Facilitation Stretching Bout on Quadriceps Neuromusc...

Effect of warm up program (plyometric - core stability- agility and dynamic stretch) on injury preve...

Veränderung der Reaktionszeit und Explosivkraftentfaltung nach einem passiven Stretchingprogramm und...