Raised troponin T and echocardiographic abnormalities after prolonged strenuous exercise--the Australian Ironman Triathlon

Background

There is concern about whether cardiac damage occurs as a result of prolonged strenuous exercise.

Objective

To investigate whether competing in a triathlon is associated with cardiac damage based on a sustained increase in cardiac troponin T (cTnT), and whether such an increase correlates with echocardiographic changes

Methods

cTnT and echocardiographic measurements were made in 38 participants in the 2001 Australian ironman triathlon. cTnT was measured the day before, immediately after, and the day following the race. Echocardiography was done the day before, immediately after, and two to six weeks later for measurement of ejection fraction, stroke volume, cardiac output, wall motion analysis, and global left ventricular function (LVF).

Results

No subject had detectable cTnT in the pre‐race sample. Following the race, 32 subjects (86.5%) had detectable levels of cTnT (>0.01 ng/ml), with six (16.2%) having >0.10 ng/ml. The day after the race, nine subjects (23.7%) still had detectable cTnT, with two recording a level >0.10 ng/ml. Previously described echocardiographic changes of “cardiac fatigue” were observed in the whole cohort. There was a modest but significant correlation between change in ejection fraction and peak cTnT level (p = 0.02, r = 0.39). Athletes with a post‐race cTnT >0.10 ng/ml had a greater decrease in global LVF (p = 0.02) and a trend toward a greater fall in ejection fraction and stroke volume than athletes with cTnT levels <0.10 ng/ml. Cardiac output fell in the group with cTnT >0.10 ng/ml (p>0.05).

Conclusions

Participation in ironman triathlon often resulted in persistently raised cTnT levels, and the troponin rise was associated with echocardiographic evidence of abnormal left ventricular function. The clinical significance and long term sequelae of such damage remains to be determined.     

维生素E与青蒿琥酯的抗疟机制

在鼠疟模型上观察了维生素Ｅ对青蒿琥酯抗疟作用的影响。流式细胞仪的测定结果表明，青蒿琥酯可抑制疟原虫ＤＡＮ的合成，而补充维生素Ｅ后这种作用减弱。可见宿主体内维生素Ｅ的水平可影响青蒿琥酯的抗疟作用。     

Video analysis of acute injuries and referee decisions during the 24th Men's Handball World Championship 2015 in Qatar

Although handball is a contact sport with a high risk of acute match injuries, their mechanisms have not yet been investigated. We aimed to describe the mechanisms of acute match injuries in elite male handball and evaluate referee performance in injury situations. Based on injury surveillance from the 24th Men′s Handball World Championship 2015 in Qatar, injury situations and the referee decisions were identified on video footage. A total of 55 injury situations and 37 referee decisions were included for analysis. The injury situations were analyzed individually by five handball experts, followed by a consensus meeting. An expert referee panel performed individual blinded evaluation of the referee decisions, followed by an online consensus meeting. Injuries were evenly distributed among attackers (n = 29) and defenders (n = 26). The most frequent injury cause was contact trauma due to a tackle (n = 27). At the time of injury, attackers were most frequently performing a jump shot (n = 9), while defenders were completing a tackle (n = 10). Defenders most commonly tackled the throwing arm (n = 7) or toward the head/face region (n = 6) of injured attackers, while attackers most frequently hit injured defenders with the knee during jump shots (n = 5). Agreement between the referees and the expert panel was weak (kappa: 0.22, 95% CI 0.07 to 0.36), with substantially more lenient rule interpretation by the referees. Our results suggest that stricter refereeing and rule amendments should be considered to prevent acute match injuries in elite handball, especially in relation to tackling episodes when an attacker is performing a jump shot.     

Vitamin C and E supplementation blunts increases in total lean body mass in elderly men after strength training

The aim of this study was to investigate the effects of vitamin C and E supplementation on changes in muscle mass (lean mass and muscle thickness) and strength during 12 weeks of strength training in elderly men. Thirty‐four elderly males (60–81 years) were randomized to either an antioxidant group (500 mg of vitamin C and 117.5 mg vitamin E before and after training) or a placebo group following the same strength training program (three sessions per week). Body composition was assessed with dual‐energy X‐ray absorptiometry and muscle thickness by ultrasound imaging. Muscle strength was measured as one‐repetition maximum (1RM). Total lean mass increased by 3.9% (95% confidence intervals: 3.0, 5.2) and 1.4% (0, 5.4) in the placebo and antioxidant groups, respectively, revealing larger gains in the placebo group (P = 0.04). Similarly, the thickness of m. rectus femoris increased more in the placebo group [16.2% (12.8, 24.1)] than in the antioxidant group [10.9% (9.8, 13.5); P = 0.01]. Increases of lean mass in trunk and arms, and muscle thickness of elbow flexors, did not differ significantly between groups. With no group differences, 1RM improved in the range of 15–21% (P < 0.001). In conclusion, high‐dosage vitamin C and E supplementation blunted certain muscular adaptations to strength training in elderly men.     

The genetics of endurance: Frequency of the ACTN3 R577X variant in Ironman World Championship athletes

ObjectivesTo investigate the frequency of the ACTN3 R577X polymorphism in elite endurance triathletes, and whether ACTN3 R577X is significantly associated with performance time.DesignCross-sectional study.MethodsSaliva samples, questionnaires, and performance times were collected for 196 elite endurance athletes who participated in the 2008 Kona Ironman championship triathlon. Athletes were of predominantly North American, European, and Australian origin. A one-way analysis of variance was conducted to compare performance times between genotype groups. Multiple linear regression analysis was performed to model the effect of questionnaire variables and genotype on performance time. Genotype and allele frequencies were compared to results from different populations using the chi-square test.ResultsPerformance time did not significantly differ between genotype groups, and age, sex, and continent of origin were significant predictors of finishing time (age and sex: p < 5 × 10^?6; continent: p = 0.003) though genotype was not. Genotype and allele frequencies obtained (RR 26.5%, RX 50.0%, XX 23.5%, R 51.5%, X 48.5%) were found to be not significantly different from Australian, Spanish, and Italian endurance athletes (p > 0.05), but were significantly different from Kenyan, Ethiopian, and Finnish endurance athletes (p < 0.01).ConclusionsGenotype and allele frequencies agreed with those reported for endurance athletes of similar ethnic origin, supporting previous findings for an association between 577X allele and endurance. However, analysis of performance time suggests that ACTN3 does not alone influence endurance performance, or may have a complex effect on endurance performance due to a speed/endurance trade-off.     

Effect of Vitamin C and E supplementation on biochemical and ultrastructural indices of muscle damage after a 21 km run.

This study investigated whether 4 weeks of daily supplementation with 500 or 1000 mg of Vitamin C and 500 or 1000 IU of Vitamin E could modify biochemical and ultrastructural indices of muscle damage following a 21 km run. Fifteen experienced male distance runners were divided into two groups (vitamin or placebo) and received supplementation for four weeks before completing the first 21 km run in as fast a time as possible. A four-week "washout" period followed before the subjects crossed over and received the alternate supplement for the next four weeks. They then completed a second 21 km run. Before, immediately after and 24 h after each run venous blood samples were taken and analysed for serum creatine kinase, myoglobin, malondialdehyde and vitamin C and E (before-samples only) concentrations. A subgroup of six subjects also had muscle biopsy (gastrocnemius) samples taken 24 h before and 24 h after each 21 km run, which were later analysed by electron microscopy. The two dosages of supplementation produced similar results, so a single vitamin group was formed for further analysis of results. Significant increases (p < 0.05) in creatine kinase and myoglobin, but not in malondialdehyde, were found post-run in both groups. However, no significant differences were found between the vitamin and placebo groups for creatine kinase, myoglobin and malondialdehyde concentrations recorded after the 21 km runs. A qualitative ultrastructural examination of pre-run muscle samples revealed changes consistent with endurance training, but little further change was seen after the 21 km run in either the vitamin or placebo groups. It was concluded that vitamin C and E supplementation (500 or 1000 mg or IU per day) for four weeks does not reduce either biochemical or ultrastructural indices of muscle damage in experienced runners after a half marathon.     

缺血再灌注时维生素E乳剂抗氧化作用的实验研究

目的 观察缺血再灌注时肝脏脂质过氧化损害及维生素Ｅ（ＶＥ）乳剂的抗氧化保护效应。方法 采用大鼠全身低务压再灌注与肝缺血两种动物模型,检测肝脏组织丙二醛（ＭＤＡ）含量,超氧化物歧化酶（ＳＯＤ）活性及三磷酸腺苷（ＡＴＰ）含量,同时进行肝组织病理形态学观察。结果 缺血再灌注可造成肝组织ＭＤＡ含量显著增加,ＳＯＤ活性及ＡＴＰ含量显著降低。     

Health complaints and heat stress prevention strategies during taper as predictors of peaked athletic performance at the 2015 World Athletics Championship in hot conditions

ObjectivesTo investigate whether self-reported health complaints and choice of heat stress prevention strategies during the taper predicted peaking at an athletics championship in hot conditions.DesignCohort study.MethodsData on health and heat stress prevention were collected before the 2015 World Athletics Championship in Beijing, China. Peaking was defined using the athlete’s pre-competition ranking and final competition rank. Baseline and endpoint data were fitted into multiple logic regression models.ResultsTwo hundred forty-five (29%) of 841 eligible athletes participated. Both sprint/power (Odds ratio (OR) 0.33 (95% Confidence interval (CI) 0.11 to 0.94), P = 0.038) and endurance/combined events (OR 0.38 (95% CI 0.14 to 1.00), P = 0.049) athletes having sustained concern-causing health complaints during the taper were less likely to peak. Endurance/combined events athletes who chose pre-cooling to mitigate heat stress were less likely to peak (OR 0.35 (95% CI 0.15 to 0.80), P = 0.013), while sprint/power athletes reporting a sudden-onset injury complaint during the taper displayed increased peaking (OR 4.47 (95% CI 1.28 to 15.59), P = 0.019).ConclusionsHealth complaints that caused the athlete concern during the taper were predictive of failure to peak at a major athletics competition. Sprint/power athletes who experienced an acute injury symptom during the taper appeared to benefit from rest. Pre-cooling strategies seem to require further validation during real-world endurance/combined events. It appears that athletics athletes’ self-reported health should be monitored during the taper, concerns addressed, and heat stress prevention strategies individually tested before championships in hot conditions.     

维生素Eβ-环糊精包合物的制备及稳定性研究

目的采用正交试验法，研究β-CYD对VE的包合作用和稳定性。方法通过分光光度法测定包合物中VE含量，考察了VE利用率、包合率、包合物收率三个指标。结果筛选出最佳制备工艺为A282C2，经TLC、粉末X-射线衍射验证包合物确已形成。结论VE被CYD包合后稳定性明显提高。     

Vitamin and mineral supplementation and neuromuscular recovery after a running race

PURPOSE: This double-blind study investigated the effects of vitamin and mineral complex supplementation on the neuromuscular function of the knee-extensor muscles after a prolonged trail running race. METHODS: Twenty-two well-trained endurance runners took either placebo (Pl group) or vitamins and minerals (Vm group) for 21 d before the race and for 2 d after the race. Maximal voluntary contractions (MVC) and surface EMG activity of the vastus lateralis (VL) muscle were recorded before (pre) and 1 h (post), 24 h (post 24) and 48 h (post 48) after the race. Central activation ratio (CAR), neural (M-wave), and contractile (muscular twitch) properties of the quadriceps muscles were analyzed using electrical stimulation techniques. RESULTS: The knee-extensor MVC was significantly (P < 0.01) reduced after exercise for both groups (Vm: 36.5 +/- 3.0 %; Pl: 36.9 +/- 2.1%), but MVC recovery was greater for Vm than Pl after 48 h (11%, P < 0.05). The reduced MVC after exercise was associated with a significant reduction in maximal EMG normalized to the M-wave in VL muscle and in CAR for both groups. Characteristics of the muscular twitch were not significantly altered for either groups, whereas M-wave duration increased significantly (P < 0.05) after exercise. CONCLUSIONS: The reduction of MVC immediately after the race appeared to result from peripheral mechanisms such as a failure in muscle membrane excitation and, to a lesser extent, from reduced central activation. The cause of the depressed MVC 24 h after the race seemed to be located within the muscle itself. A dietary supplementation of a vitamin and mineral complex does not attenuate the loss of contractile function immediately after the running exercise, and it may accelerate the recovery of maximal force capacity.     

Vitamin E regulates changes in tissue antioxidants induced by fish oil and acute exercise

PURPOSE: Prooxidant effects of fish oil supplementation could unfavorably affect the cardiovascular benefits of fish oil. We tested the effects of 8 wk vitamin E cosupplementation with fish oil on antioxidant defenses at rest and in response to exhaustive exercise in rats. METHODS: Rats (N = 80) were divided into fish oil, fish oil and vitamin E (FOVE), soy oil, and soy oil and vitamin E (SOVE) supplemented groups. For the vitamin E supplemented rats, corresponding groups (FOVE-Ex and SOVE-Ex) performed an acute bout of exhaustive exercise after the supplementation period. RESULTS: Fish oil supplementation increased the activity of catalase, glutathione peroxidase, and glutathione-S-transferase in the liver and red gastrocnemius (RG) muscle. Fish oil decreased liver total glutathione (TGSH) levels. Vitamin E supplementation decreased antioxidant enzyme activities to levels at or near those in SOVE in a tissue specific pattern. Vitamin E increased TGSH in liver, heart, and RG. Regression analysis showed TGSH to be a negative determinant of protein oxidative damage as measured by protein carbonyl levels in both liver and RG. Catalase activity was associated with liver lipid peroxidation as measured by thiobarbituric acid-reacting substances. The exercise-induced decrease in hepatic TGSH tended to be less in FOVE versus SOVE. Exhaustive exercise also modulated tissue antioxidant enzymes. CONCLUSIONS: Vitamin E supplementation markedly decreased fish oil induced antioxidant enzyme activities in all tissues. Sparing of glutathione may be an important mechanism by which vitamin E decreased tissue protein oxidative damage.     

Musculoskeletal and head injuries in the Ultimate Fighting Championship (UFC)

Objectives: Mixed martial arts (MMA) has witnessed a surge in popularity worldwide. This study explores the musculoskeletal and head injuries sustained in the professional fights of the Ultimate Fighting Championship (UFC), and establishes associations between injury profiles and impactful contributory factors.

Methods: The Nevada State Athletic Commission database was screened for ringside physician reports of UFC fights between January 2016 and July 2018. Information on the fighter’s gender, weight, injury, way of finish, and match result were collected. Injury rates were calculated and statistical analyses were conducted to determine significant associations among variables. P-values <0.05 were considered significant (95% CI).

Results: A total of 291 injuries were recorded in 285 fights from nine weight divisions. The overall injury rate was 51 per 100 athletic exposures (AE). Males predominantly partook in 249 matches (87%) and had higher injury rates (54 injuries per 100 AE) than females (30 injuries per 100 AE). Decision was the most common way a match ended. Knockouts (KOs) were significantly higher in males (36%) than in females (14%, P = 0.0007). Submissions were significantly higher in females (36%) than in males (16%, P = 0.001). Head injuries (67%) were the most common injuries reported with a rate of 34 per 100 AE. Upper limb injuries were significantly higher in females (40%) than in males (14%, P = 0.0003). Lower limb injuries were significantly higher in males (19%) than in females (5%, P = 0.01). Head injuries were significantly associated with KOs (P < 0.0001). Upper limb injuries (P = 0.032) and lower limb injuries (P = 0.034) were significantly associated with matches that ended with Decision. Trend-line analyses showed that as weight division increases, overall injury rates, head injuries, lower limb injuries, and KOs’ frequency increase, whereas upper limb injuries, Submission frequency, and Decision frequency decrease.

Conclusion: MMA has a high injury rate. Gender, way of finish, and weight play an important role in predicting fight outcomes and injury profiles. Injury prevention policies must be entertained to limit injury risk in MMA.     

The -55 C/T polymorphism within the UCP3 gene and performance during the South African Ironman Triathlon

Uncoupling protein 3 is believed to be involved in total body energy expenditure, including the regulation of fat and glucose metabolism. These biochemical processes may distinguish top ultra-endurance triathletes from slower competitors. The aim of this study was to determine whether the uncoupling protein 3 gene is associated with the performance capacity of ultra-endurance Ironman triathletes. Two triathlete groups consisting of the 89 fastest and 89 slowest Caucasian, male triathletes who completed either the 2000 or 2001 South African Ironman triathlon events were genotyped for the -55 C/T polymorphism within the uncoupling protein 3 gene. A control group consisting of 92 Caucasian males who had not trained for or participated in an ultra-endurance athletic event was also genotyped. There was no significant difference in the genotype (CC, CT and TT) frequency distribution of the -55 C/T polymorphism within the uncoupling protein 3 gene between the fast triathlete, slow triathlete and control groups. In addition, no significant differences were observed between the frequencies of the C and T alleles between the three groups. The two triathlete groups were combined and grouped according to their genotype. No particular genotype or allele was associated with the time taken by the triathletes to complete the entire triathlon, or either the swim, cycle or run legs of the event. Thus no association was found between the -55 C/T polymorphism within the uncoupling protein 3 gene and the ultra-endurance performance of triathletes who completed either the 2000 or 2001 South African Ironman triathlons.     

Effects of oat beta-glucan on innate immunity and infection after exercise stress

PURPOSE: To test the effects of oat beta-glucan (ObetaG) on respiratory infection, macrophage antiviral resistance, and NK cytotoxicity. METHODS: Mice were randomly assigned to one of four groups: Ex-H2O, Ex-ObetaG, Con-H2O, or Con-ObetaG. ObetaG was fed in the drinking water for 10 d before intranasal inoculation of HSV-1 or sacrifice. Exercise consisted of treadmill running to volitional fatigue (approximately 140 min) for three consecutive days. Fifteen minutes after the last bout of exercise or rest, mice (N = 24) were intranasally inoculated with a standardized dose of HSV-1. Mice were monitored twice daily for morbidity and mortality. Additional mice were sacrificed after exercise, peritoneal macrophages were obtained via i.p. lavage and assayed for antiviral resistance to HSV-1 (N = 18), and spleens were harvested and assayed for NK cell cytotoxicity (N = 12). RESULTS: Exercise stress was associated with a 28% increase in morbidity (P = 0.036) and 18% increase in mortality (P = 0.15). Ingestion of ObetaG before infection prevented this increase in morbidity (P = 0.048) and mortality (P = 0.05). Exercise stress was associated with a decrease in macrophage antiviral resistance (P = 0.007), which was blocked by ingestion of ObetaG (P < 0.001). There were no effects of exercise or ObetaG on NK cytotoxicity. CONCLUSION: These data suggest that daily ingestion of ObetaG may offset the increased risk of URTI associated with exercise stress, which may be mediated, at least in part, by an increase in macrophage antiviral resistance.     

Heart rate and GPS data analysis of kiteboard course racing during the Italian Championship

Background

Despite the growing popularity of kiteboard course racing, there is a paucity of scientific literature about the performance in this sport.

Purpose

The aim of the present study was to analyze displacement (speed and direction) and heart rate (HR) data in high-level kiteboarders during competition.

Methods

Five kiteboarders, ages 33.8 ± 5.3 years, weight: 80.6 ± 4.8 kg, height: 181.2 ± 7.8 cm, were monitored with a GPS receiver and an HR monitor during four races of the Italian Kiteboarding Championship for a total of 46 regattas.

Results

Each regatta lasted 926 ± 175 s and was composed by 11 ± 1 beats. The average sailing speed recorded in competition was 8.9 ± 0.9 m/s. The speed was higher (p < 0.01) in the downwind leg (9.9 ± 1.4 m/s) than in the upwind leg (7.9 ± 0.3 m/s). The orientation of the kiteboard with respect to the wind direction during the upwind sailing phase was 66.4° ± 6.3°, resulting in being wider than in traditional sailing sports. The mean HR was 82.7 ± 0.9% of HR_reserve and 86% ± 1.2 HR_max, showing a relatively high exercise intensity compared to most of other sailing sports.

Conclusion

The duration and intensity of a kiteboard racing suggest the need of specific physical training programs for competitive kiteboarders.