Exercise-associated Muscle Cramps Research Articles

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

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

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

To determine independent risk factors associated with a history of exercise-associated muscle cramps (hEAMCs) in distance runner race entrants in a community-based mass participation event. Cross-sectional study. 2012 to 2015, Two Oceans marathon races (21.1 and 56 km), South Africa. Seventy six thousand six hundred fifty-four consenting race entrants. Entrants completed an online prerace medical screening questionnaire as part of the entry process. In a multiple model, sex, age, training variables, history of chronic disease, allergies, and running injuries were included as potential factors associated with hEAMC in 21.1 and 56 km entrants. Prevalence (%) and prevalence ratios (PRs, 95% confidence intervals) are reported. Men ( P < 0.0001) and older age (>40 years, P < 0.0001) were significantly associated with hEAMC. Therefore, the model was adjusted for sex and age group and run separately for 21.1- and 56-km entrants. Specific independent risk factors associated with hEAMC in 21.1- and 56-km entrants were: a history of chronic diseases (21.1 km: PR = 1.9; 56 km: PR = 1.6; P < 0.0001), running injury in the last 12 months (21.1 km: PR = 1.7; 56 km: PR = 1.4; P < 0.0001), history of allergies (21.1 km: PR = 1.4; 56 km: PR = 1.2; P < 0.0001), and various training variables (PR = 1.0-1.1). In 21.1- and 56-km race entrants, independent risk factors associated with hEAMC were men, older age, longer race distances, training variables, chronic diseases, history of allergies, and history of a running injury in the past 12 months.

CLASSIFICATION OF EXERCISE-ASSOCIATED MUSCLE CRAMPS IN IRONMAN-DISTANCE TRIATHLETES OVER THREE DECADES

Exercise-associated muscle cramps (EAMC) is a common condition in ultra-endurance athletic events. Despite its high incidence, the etiology and risk factors are not fully understood. PURPOSE: The purpose of this study was to explore trends in Ironman-distance triathletes, that presented to the medical tent during competition with muscle cramping as well as those who returned with subsequent cramping after initial treatment. METHODS: Medical records (n=10,553) from the 1989-2019 Ironman World Championship (Kona, HI) were reviewed. Independent samples t-tests were run and odds ratios were calculated to compare athletes with cramping (n=2,859) to those without (n=7,670). The same analyses were used to compare those who returned to the tent with muscle cramps (n=377) to those who had muscle cramps and did not subsequently return with muscle cramps (n=2,248). RESULTS: Triathletes who presented with muscle cramps were more likely to have a history of previously reporting to the medical tent with muscle cramps within the same race compared to those presenting without muscle cramps (OR 2.40; 95% CI = 1.91-3.03). Triathletes who presented with muscle cramps had slightly higher serum sodium (140 +/- 7 vs. 139 +/- 7 mEq/L, p = .007) and potassium (4.3 +/- 0.7 vs. 4.2 +/- 0.6 mEq/L, p < .001) concentrations than those without muscle cramps. Dehydration was more common in triathletes with muscle cramps (OR 1.63; 95% CI = 1.49-1.78) compared to those without. Male triathletes were much more likely to present with muscle cramps than female triathletes (29 vs. 22%, p < .001). For those returning to the medical tent with muscle cramps, faster race completion time was associated with increased risk of returning with muscle cramps (11.0 +/- 1.9 vs. 11.4 +/- 1.8 hours, p < .001). CONCLUSIONS: Our findings from nearly 30 years of elite ultra-endurance data indicate that muscle cramps are likely to be a reoccurring issue throughout the race and are more common among males. We confirm that electrolyte abnormalities are not associated with muscle cramps during ultra-endurance competition. Our finding that dehydration is associated with muscle cramps is somewhat contradictory to current literature.

Chronic Prescription Medication Is Associated With A History Of Exercise Associated Muscle Cramps In Runners

INTRODUCTION: The prevalence of chronic prescription medication (CPM) use in recreational distance runners is 12.5%. CPM use in endurance athletes is associated with a history of exercise associated muscle cramps (hEAMC), but which main categories of CPM are associated with hEAMC has not been explored. PURPOSE: To determine the association between the use of main categories of CPM and a hEAMC. METHODS: 76654 consenting entrants (71.8% of all entrants) in two annual races (21.1 km & 56 km) were studied from 2012-2015. CPM use and type of medication in 8 main categories were self-reported as part of an online pre-race medical screening questionnaire at race entry. Entrants reported demographics (age, sex, and race distance), CPM use in 8 categories (blood pressure-lowering, asthma, cholesterol-lowering, anxiety/depression, allergy, any diabetes, any heart, other medication) and hEAMC. The prevalence (%; 95%CI) and prevalence ratio’s (PR; 95%CI) of main categories of CPM use in runners with (E group) and without hEAMC (C group) are reported, using a multinominal logistic regression model (adjusted for age, gender, and race distance). RESULTS: CPM use was significantly higher in the E vs. C group for main categories of medication use (prevalence in %; PR in decreasing order; 95%CIs): allergy (E: 1.5; 1.2-1.8 vs C: 0.8; 0.7-0.9, PR = 2.1; 1.7-2.6; p < 0.0001); asthma (E: 3.9; 3.5-4.3 vs C: 2.4; 2.3-2.5, PR = 1.8; 1.6-2.0; p < 0.0001); anxiety/depression (E: 3.0; 2.6-3.4 vs C: 2.1; 2.0-2.2, PR = 1.6; 1.4-1.8; p < 0.0001); any diabetes (E: 0.9; 0.7-1.1 vs C: 0.6; 0.6-0.7, PR = 1.5; 1.2-2.0; p < 0.01); blood pressure-lowering (E: 3.8;3.4-4.2 vs C: 3.0;2.8-3.2, PR = 1.4;1.3-1.6; p < 0.0001); cholesterol-lowering (E: 3.6; 3.2-4.0 vs C: 2.9; 2.7-3.0, PR = 1.4; 1.2-1.6; p < 0.0001). CONCLUSIONS: CPM use is associated with hEAMC in endurance athletes and may contribute to EAMC. Specific main categories of medication associated with >1.5X risk of hEAMC are allergy medication, asthma medication, medication to treat anxiety/depression, and any diabetes medication.

Exercise-associated muscle cramps and creatine kinase responses after workload spikes in a professional soccer player: a case study

Purpose.Exercise-associated muscle cramps (EAMC) are characterized by intense pain and involuntary contractions of a single muscle or muscle group. While EAMCs may occur during and after exercise, their precise aetiology remains unknown. However, there are some potential risk factors, as the workload of physical training previously performed. The purpose of this case report was to evaluate the acute:chronic workload ratio (ACWR) and creatine kinase (CK) concentrations in a professional soccer player to verify the potential influence of recent training history on an extreme EAMC episode and subsequent muscle damage.Methods.A 21-year-old professional soccer player (body fat: 6.5%; body mass: 76 kg; height: 1.76 m) who experienced an extreme EAMC episode after the end of an official soccer match was monitored with session rating of perceived exertion before and after the EAMC episode and with post-match CK concentrations.Results.ACWR revealed several spikes on the days before the match, with the highest one observed on the match day. The CK concentrations recorded 35 and 53 hours after the EAMC episode were 262% and 182% higher, respectively, than the maximal CK concentrations recorded during the season (703 U/l).Conclusions.This case report illustrates, for the first time, how workload spikes, monitored with ACWR, preceded an extreme EAMC episode that was followed by an exacerbated muscle damage response. Some insights are provided in this case report for practitioners working in professional soccer to help them better manage similar cases.

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

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

Medical emergencies during running events

HintergrundDie Anzahl an kurz- und langstreckigen Laufveranstaltungen in Deutschland nimmt zu. Laufen als Breitensport wird von einer Vielzahl an Personen unterschiedlicher Altersklassen, Risikogruppen und Professionalisierungsgrade betrieben, woraus ein breites Spektrum medizinischer Notfälle resultiert.Ziel der ArbeitDer vorliegende Beitrag erläutert die Inzidenz, Pathophysiologie und Therapie relevanter Notfallbilder bei Laufveranstaltungen. Ziel ist die Optimierung der Arbeitsabläufe des Rettungsdienstpersonals.Material und MethodenEs erfolgte eine Literaturrecherche in PubMed.ErgebnisseAnstrengungsassoziierte Muskelkrämpfe, gastrointestinale Symptome, Kollaps, Kompartmentsyndrom und Tendinopathien sind häufige Erscheinungsbilder und resultieren meist aus akuter oder chronischer Überanstrengung. Der Kreislaufstillstand bzw. plötzliche Herztod ist ein seltenes Ereignis bei Laufveranstaltungen. Bewusstseinsstörungen und generalisierte Krampfanfälle sind schwerwiegende Komplikationen. Disseminierte intravasale Koagulopathie, belastungsinduzierte Hyponatriämie, Hitzschlag, Rhabdomyolyse und thromboembolische Ereignisse sind mit hoher Morbidität und Mortalität verbunden. Substanzen zur Erhöhung der Schmerzschwelle und leistungssteigernde Substanzen sind unter Läufern stark verbreitet und gehen mit einer hohen Rate an Nebenwirkungen einher.DiskussionUnspezifische Symptome wie Erbrechen, Fieber, Kollaps, Muskelschmerzen, Übelkeit, und Schwäche sind die führenden Symptome bei Laufveranstaltungen. Eine sorgfältige Anamnese ist wegweisend für eine zielgerichtete klinische Therapie. Präklinisch steht eine Symptomkontrolle im Mittelpunkt. Das Flüssigkeitsmanagement stellt eine besondere Herausforderung dar.

Exercise-associated Muscle Cramps in Runners: A Review

Objective: Exercise-associated Muscle Cramp (EAMC) is an intense, painful, and involuntary contraction of skeletal muscles during a physical activity. Runners are more prone to this syndrome than other athletes. The present paper aims to review of the literature on EAMC in runners to determine the reasons and nature of EAMC in this sports field. Methods: A search was conducted for related studies from 1997 to 2021 in MEDLINE/PubMed, EMBASE/SCOPUS, LILACS, CINAHL, CENTRAL, Web of Science, PEDro, Google Scholar as well as MagIran, IranDoc, IranMedex, MedLib using MeSH Keywords. The reference section of the studies were also checked to find more studies. Finally, 15 eligible papers on EAMC in runners were reviewed and findings were reported. Results: Several factors were found to be effective in EAMC among runners, including dehydration, electrolyte deficit, cold, long training or competition period, increased body temperature during training or competition, history of injury or muscle cramp, increased training intensity in short time, and dietary restrictions. Conclusion: The cause of EAMC in runners seems to be multifactorial.

Exertional Rhabdomyolysis Following Noncontact Collegiate Recreational Activity: A Case Report

A healthy 19-year-old male (body mass = 68.04 kg, height = 175.26 cm) participating in a collegiate intramural flag football tournament presented with unilateral gastrocnemius exercise-associated muscle cramps. He was given electrolytes, stretched, and returned to play. The exercise-associated muscle cramps progressed to his quadriceps bilaterally within 23 min of initial reported symptoms. Emergency medical services was activated and the patient was transported by ambulance to the emergency department, where he was diagnosed with acute exertional rhabdomyolysis. This case report explores the rarity of exertional rhabdomyolysis in a noncontact intramural sport and highlights the necessity for early recognition and treatment.

Total Body and Extracellular Water Measures Are Unrelated to Cramp Sensitivity in Euhydrated Cramp-Prone Individuals.

Earp, JE, Stearns, RL, Agostinucci, J, Lepley, AS, and Ward-Ritacco, CL. Total body and extracellular water measures are unrelated to cramp sensitivity in euhydrated cramp-prone individuals. J Strength Cond Res 36(9): 2653-2656, 2022-Spectral bioelectrical impedance analysis (BIA) is a valid and noninvasive tool for measuring total body water (TBW), intracellular water (ICW), and extracellular water (ECW). As altered hydration and electrolyte imbalance have been proposed as one of 2 etiologies for exercise-associated muscle cramps (EAMC), the purpose of this study was to determine if distribution of body water is related to cramp sensitivity in similarly hydrated cramp-prone individuals. To this end, 11 euhydrated subjects who regularly experience EAMC had their relative TBW, ICW, and ECW assessed using 8-pole spectral BIA. Subjects' cramp sensitivity was then assessed by electrically stimulating the tibial nerve at increasing frequencies until a muscle cramp occurred, allowing for the determination of the threshold frequency (TF) at which the cramp occurred. It was observed that TF was not significantly related to TBW ( r = 0.087, p = 0.368), ICW ( r = 0.105, p = 0.338), ECW ( r = 0.087, p = 0.368), or ECW:TBW ( r = 0.147, p = 0.280). As cramp etiology is poorly understood, these results add to a growing body of literature questioning the role of hydration and electrolyte imbalance in EAMC. Although fluid distribution may be unrelated to TF in those who commonly experience EAMC, additional research is needed to compare those who commonly experience cramps (athletes as well as individuals with specific neuropathies or pharmacologically induced cramps) with those who do not experience cramps and to determine if acute shifts in body water compartmentalization are related to changes in cramp sensitivity.

Magnesium for skeletal muscle cramps.

Magnesium for skeletal muscle cramps.

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

Martínez-Navarro, I, Montoya-Vieco, A, Collado, E, Hernando, B, Panizo, N, and Hernando, C. Muscle Cramping in the marathon: Dehydration and electrolyte depletion vs. muscle damage. J Strength Cond Res 36(6): 1629-1635, 2022-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.

Exercise-Associated Muscle Cramps in the Tennis Player

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

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

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.

Sweat Characteristics of Cramp-Prone and Cramp-Resistant Athletes.

Exercise-associated muscle cramps (EAMCs) are thought to be caused by dehydration and/or electrolyte losses. In this multicenter, cross-sectional study, the authors determined whether sweat rates (SRs), sweat electrolyte concentrations, or sweat electrolyte content differed in athletes with (i.e.,crampers) and without (i.e.,noncrampers) a history of EAMCs and whether these variables could predict EAMC-prone athletes. Male and female collegiate athletes (N = 350) from 11 sports with (n = 245) and without (n = 105) a self-reported history of EAMCs completed a typical exercise or conditioning session. SRs, calculated from body mass, and posterior forearm sweat were analyzed for sweat sodium concentration ([Na+]sw), sweat potassium concentration ([K+]sw), and sweat chloride concentration ([Cl-]sw). The authors used SRs and sweat electrolyte concentrations to calculate sweat electrolyte content lost. Within each gender, no differences in SRs (204 males, p = .92; 146 females, p = .24); [Na+]sw (191 males, p = .55; 126 females, p = .55); Na+sw content (191 males, p = .59; 126 females, p = .20); [K+]sw (192 males, p = .57; 126 females, p = .87); K+sw content (192 males, p = .49; 126 females, p = .03); [Cl-]sw (192 males, p = .94; 77 females, p = .57); and Cl-sw content (192 males, p = .55; 77 females, p = .34) occurred between crampers and noncrampers. Receiver operating characteristic curve analysis revealed that sweat electrolyte content and SRs were predictive of EAMC-prone athletes in American football (area under curve = 0.65-0.72, p ≤ .005), but not in any other sport. EAMCs may not be solely caused by fluid or electrolyte losses in most athletes. Fluid and electrolyte replacement may help American footballers. Clinicians should individualize fluid and electrolyte replacement and understand different etiologies for EAMCs.

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

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

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

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

Acute Passive Static Stretching and Cramp Threshold Frequency.

Exercise-associated muscle cramps are a common clinical problem for athletes. To determine whether acute passive static stretching altered cramp threshold frequency (CTF) of electrically induced muscle cramps. Crossover study. Laboratory. Seventeen healthy college-aged individuals. Stretching or no stretching. The independent variable was the static stretch versus the no-stretch condition, and the dependent variable was the CTF. The CTF increased in both the control (pretest: 18.12 ± 6.46 Hz, posttest: 19.65 ± 7.25 Hz; P = .033) and stretching (pretest: 18.94 ± 5.96 Hz, posttest: 20.47 ± 7.12 Hz; P = .049) groups. No difference between the groups was found (t15 = 0.035, P = .97). Acute passive static stretching did not seem to increase the CTF.

Fueling the Triathlete: Evidence-Based Practical Advice for Athletes of All Levels.

Triathletes need to effectively fuel during training and racing to maximize their potential for success. While most research on fueling has focused on elite male triathletes, triathlon participation encompasses a broader demographic of racers ranging from those with aspirations of winning to those whose goals are completion. Carbohydrate is the primary macronutrient for fueling endurance activities. Athletes can usually tolerate 60 to 90 mg·h in the form of multiple different carbohydrate sources. Athletes should drink as thirst dictates and consider sodium replacement of sweat loss especially in individuals with a history of exercise-associated muscle cramps. Caffeine is a known ergogenic aid that could be dosed at 3 mg·kg to maximize benefits of mental alertness while limiting potential side effects. Athletes need to balance fueling with development of exercise-induced gastrointestinal syndrome. As demographics of race participants change, understanding the special fueling needs of obese triathletes can encourage participation while minimizing bad outcomes.

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

Previous data indicate that a strong sensory input from orally administered TRPV1 and TRPA1 activators alleviates muscle cramps in foot muscles by reducing the α-motor neuron hyperexcitability. We investigated if TRP activators increase the cramp threshold frequency of the medial gastrocnemius. We randomly assigned 22 healthy male participants to an intervention (IG) and a control group (CG). While participants of the IG ingested a mixture of TRPV1 and TRPA1 activators, the CG received a placebo. We tested the cramp threshold frequency (CTF), the cramp intensity (EMG activity), and the perceived pain of electrically induced muscle cramps before (pre), and 15min, 4, 8, and 24h after either treatment. We further measured the maximal isometric force of knee extensors at pre, 4, and 24h to assess potential side-effects on the force output. When we included all measurement time points, no group-by-time interaction was observed for the CTF. However, when only pre and 15min values were incorporated, a significant interaction, with a slightly greater CTF increase in IG (3.1±1.5) compared to the CG (2.0±1.5), was observed. No significant group by time interaction was found for the cramp intensity, the perceived pain, and the maximal isometric force. Our data indicate that orally administered TRPV1 and TRPA1 activators exert a small short-term effect on the CTF, but not on the other parameters tested. Future studies need to investigate whether such small CTF increments are sufficient to prevent exercise-associated muscle cramps.