Effect of NSAID on Muscle Injury and Oxidative Stress

Using machine learning to determine the nationalities of the fastest 100-mile ultra-marathoners and identify top racing events

The present study intended to determine the nationality of the fastest 100-mile ultra-marathoners and the country/events where the fastest 100-mile races are held. A machine learning model based on the XG Boost algorithm was built to predict the running speed from the athlete's age (Age group), gender (Gender), country of origin (Athlete country) and where the race occurred (Event country). Model explainability tools were then used to investigate how each independent variable influenced the predicted running speed. A total of 172,110 race records from 65,392 unique runners from 68 different countries participating in races held in 44 different countries were used for analyses. The model rates Event country (0.53) as the most important predictor (based on data entropy reduction), followed by Athlete country (0.21), Age group (0.14), and Gender (0.13). In terms of participation, the United States leads by far, followed by Great Britain, Canada, South Africa, and Japan, in both athlete and event counts. The fastest 100-mile races are held in Romania, Israel, Switzerland, Finland, Russia, the Netherlands, France, Denmark, Czechia, and Taiwan. The fastest athletes come mostly from Eastern European countries (Lithuania, Latvia, Ukraine, Finland, Russia, Hungary, Slovakia) and also Israel. In contrast, the slowest athletes come from Asian countries like China, Thailand, Vietnam, Indonesia, Malaysia, and Brunei. The difference among male and female predictions is relatively small at about 0.25 km/h. The fastest age group is 25-29 years, but the average speeds of groups 20-24 and 30-34 years are close. Participation, however, peaks for the age group 40-44 years. The model predicts the event location (country of event) as the most important predictor for a fast 100-mile race time. The fastest race courses were occurred in Romania, Israel, Switzerland, Finland, Russia, the Netherlands, France, Denmark, Czechia, and Taiwan. Athletes and coaches can use these findings for their race preparation to find the most appropriate racecourse for a fast 100-mile race time.

The Effect of Pressotherapy on Performance and Recovery in the Management of Delayed Onset Muscle Soreness: A Systematic Review and Meta-Analysis

Background: It has been demonstrated that pressotherapy used post-exercise (Po-E) can influence training performance, recovery, and physiological properties. This study examined the effectiveness of pressotherapy on the following parameters. Methods: The systematic review and meta-analysis were performed according to PRISMA guidelines. A literature search of MEDLINE, PubMed, EBSCO, Web of Science, SPORTDiscus, and ClinicalTrials has been completed up to March 2021. Inclusion criteria were: randomized control trials (RCTs) or cross-over studies, mean participant age between 18 and 65 years, ≥1 exercise mechanical pressotherapy intervention. The risk of bias was assessed by the Cochrane risk-of-bias tool for RCT (RoB 2.0). Results: 12 studies comprised of 322 participants were selected. The mean sample size was n = 25. Pressotherapy significantly reduced muscle soreness (Standard Mean Difference; SMD = −0.33; CI = −0.49, −0.18; p < 0.0001; I2 = 7%). Pressotherapy did not significantly affect jump height (SMD = −0.04; CI = −0.36, −0.29; p = 0.82). Pressotherapy did not significantly affect creatine kinase level 24−96 h after DOMS induction (SMD = 0.41; CI = −0.07, 0.89; p = 0.09; I2 = 63%). Conclusions: Only moderate benefits of using pressotherapy as a recovery intervention were observed (mostly for reduced muscle soreness), although, pressotherapy did not significantly influence exercise performance. Results differed between the type of exercise, study population, and applied treatment protocol. Pressotherapy should only be incorporated as an additional component of a more comprehensive recovery strategy. Study PROSPERO registration number—CRD42020189382.

ANTI-INFLAMMATORIES FOR DELAYED ONSET MUSCLE SORENESS: SYSTEMATIC REVIEW AND META-ANALYSIS

ABSTRACT Objective: To investigate the effectiveness of pharmacological interventions in the treatment of delayed onset muscle soreness (DOMS). Design: A systematic review and meta-analysis of randomized controlled clinical trials (RCTs). Data sources: The PubMed/MEDLINE, EMBASE, SPORTDiscus, Scielo and Cochrane Central Register of Controlled Trials (CENTRAL) databases were searched for RCTs published prior to August 3, 2020. Eligibility criteria for selecting studies: Studies that 1) used an RCT design; 2) evaluated the effectiveness of steroidal or nonsteroidal anti-inflammatory drugs (NSAIDs) in treating DOMS; and 3) therapeutically used drugs after exercise were included. Results: In total, 26 studies (patients = 934) were eligible for inclusion in the qualitative analysis on the treatment of DOMS. The results of the meta-analysis showed no superiority between the use and non-use of NSAIDs in the improvement of late muscle pain, as no statistically significant differences were verified (21 studies, n= 955; standard mean difference (SMD)= 0.02; 95% confidence interval (CI) −0.58, 0.63; p=0.94; I2=93%). The quality of the synthesized evidence was very low according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) criteria, and there was significant heterogeneity among the included studies. Conclusion: The results demonstrate that NSAIDs are not superior to controls/placebos in treating DOMS. The inclusion of both studies with dose-response protocols and those with exercise protocols may have influenced the results. In addition, the high risk of bias identified reveals that limitations need to be considered when interpreting the results. Level of evidence I; ystematic review of RCT (Randomized and Controlled Clinical Trials).

Effects of microplastic exposure on the blood biochemical parameters in the pond turtle (Emys orbicularis)

The accumulation of microplastics (MPs) is a growing problem in aquatic ecosystems. Despite increased research on MPs in the last decade, their potential threat to freshwater ecosystems remains an open question. In the present study, the negative impacts of MPs were investigated on blood biochemical parameters in the European pond turtle (Emys orbicularis). Pond turtles were distributed into three experimental groups (n = 9 for each group) and were fed diets containing 250, 500, and 1000 mg MPs (PE100 polyethylene) per kg of food for 30 days, and a control group fed with a standard uncontaminated diet. The results indicated that exposure to 500 and 1000 mg kg^-1 MPs caused a significant increase in the activities of alanine and aspartate aminotransferases, and in the levels of cholesterol, glucose, creatinine, urea, and calcium (Ca⁺²) compared with the control group. On the contrary, the activity of gamma-glutamyl transferase and the levels of total protein, albumin, total immunoglobulins, and phosphorus were significantly reduced in E. orbicularis exposed to 500 and 1000 mg kg^-1 MPs when compared with the controls. In all the MP-exposed groups, the activity of lactate dehydrogenase and globulin and magnesium (Mg⁺²) levels were significantly reduced; while creatine phosphokinase and alkaline phosphatase activities were increased with respect to the control turtles. A significant decrease in triglyceride levels was reported in E. orbicularis exposed to 1000 mg kg^-1 MPs. MPs intake induced notable alterations in blood biochemical parameters of E. orbicularis. These results suggest that changes in the blood biochemical parameters could be an appropriate bio-indicator to evidence the existence of tissue damage in E. orbicularis.

Chronological effects of non-steroidal anti-inflammatory drug therapy on oxidative stress and antioxidant status in patients with rheumatoid arthritis

INTRODUCTION/OBJECTIVES

Non-steroidal anti-inflammatory drugs (NSAIDs) are effective in reducing pain and inflammation in rheumatoid arthritis and other joint- and muscle-associated diseases. However, the extensive, long-term, and over the counter administration of NSAIDs may cause various side effects in the patients. In the present study, the chronological effect of NSAIDs on oxidative stress and antioxidant status in patients with rheumatoid arthritis was studied.

METHODS

The study included 100 female individuals categorized in four major groups: (1) control group consisting of age- and gender-matched healthy individuals, (2) NRA-NSAID individuals taking NSAIDs without any history of RA, (3) RA individuals with a history of RA but not taking NSAIDs, and (4) RA-NSAID individuals with chronic RA and taking NSAIDs for a long period. The sera of the participants were analyzed for the oxidative stress and antioxidant status.

RESULTS

The RA-NSAID group showed the significantly highest oxidative stress, in terms of malondialdehyde content and lipid-reducing ability as determined in thiocyanate and hemoglobin-induced linoleic acid systems. However, the free radical scavenging ability of the RA-NSAID group, against 2,2-diphenyl-1-picrylhydrazyl, hydroxyl, superoxide, and 2,2-azino-bis-tetrazolium sulfate radicals, was found to be lower than those of the other study groups. The regression analysis of the experimental data showed a significant positive relationship between duration of NSAID intake and malondialdehyde production, lipid-reducing ability, and metal chelating ability in the RA-NSAID patients. The free radical scavenging abilities of the RA-NSAID group were negatively correlated with the duration of NSAID intake.

CONCLUSIONS

The prolonged use of NSAIDs significantly increased the oxidative stress and decrease the antioxidant potential of both the RA patients and NRA individuals. The study provides awareness to the public particularly the RA patients regarding the risk of oxidative stress-associated abnormalities caused by the frequent and prolonged use of NSAIDs for temporary relief from pain. Key Points • The study presents the effects of long-term use of non-steroidal anti-inflammatory drugs (NSAIDs) on antioxidant status of patients with rheumatoid arthritis. • The continuous administration of NSAIDs has been found to significantly increase the oxidative stress of the patients with rheumatoid arthritis as well as the individuals with no signs of rheumatoid arthritis. • The prolonged NSAID therapy also decreased the antioxidant potential of the patients with rheumatoid arthritis as well as the individuals with no signs of rheumatoid arthritis. • The study would be a significant and valuable contribution to the literature for the awareness regarding the use of NSAIDs.

Platelet releasate promotes skeletal myogenesis by increasing muscle stem cell commitment to differentiation and accelerates muscle regeneration following acute injury

AIM

The use of platelets as biomaterials has gained intense research interest. However, the mechanisms regarding platelet-mediated skeletal myogenesis remain to be established. The aim of this study was to determine the role of platelet releasate in skeletal myogenesis and muscle stem cell fate in vitro and ex vivo respectively.

METHODS

We analysed the effect of platelet releasate on proliferation and differentiation of C2C12 myoblasts by means of cell proliferation assays, immunohistochemistry, gene expression and cell bioenergetics. We expanded in vitro findings on single muscle fibres by determining the effect of platelet releasate on murine skeletal muscle stem cells using protein expression profiles for key myogenic regulatory factors.

RESULTS

TRAP6 and collagen used for releasate preparation had a more pronounced effect on myoblast proliferation vs thrombin and sonicated platelets (P < 0.05). In addition, platelet concentration positively correlated with myoblast proliferation. Platelet releasate increased myoblast and muscle stem cell proliferation in a dose-dependent manner, which was mitigated by VEGFR and PDGFR inhibition. Inhibition of VEGFR and PDGFR ablated MyoD expression on proliferating muscle stem cells, compromising their commitment to differentiation in muscle fibres (P < 0.001). Platelet releasate was detrimental to myoblast fusion and affected differentiation of myoblasts in a temporal manner. Most importantly, we show that platelet releasate promotes skeletal myogenesis through the PDGF/VEGF-Cyclin D1-MyoD-Scrib-Myogenin axis and accelerates skeletal muscle regeneration after acute injury.

CONCLUSION

This study provides novel mechanistic insights on the role of platelet releasate in skeletal myogenesis and set the physiological basis for exploiting platelets as biomaterials in regenerative medicine.

Non-steroidal Anti-inflammatory Drug Consumption in a Multi-Stage and a 24-h Mountain Bike Competition

Purpose: Excessive or inappropriate non-steroidal anti-inflammatory drug (NSAID) use during ultra-endurance events could cause potential risk to athletes’ health. Reports on NSAID consumption in mountain bikers or ultra-mountain bikers are scarce. Therefore, the aim of this study was to investigate the prevalence of NSAID consumption immediately before, during and immediately after a mountain bike (MTB) race and to compare NSAID consumption in two different MTB competitions.

Methods: This observational study took place at a three-stage MTB race (SMTB) (n = 63) and at a 24-h MTB race (24MTB) (n = 68), both held in the Czechia in 2017. NSAID consumption was evaluated via self-reported electronic questionnaires.

Results: Of all finishers (n = 131), fourteen (10%) consumed NSAID at least once during the competition day (immediately before, during or immediately after the race). The number of NSAID consumers was the same in both competitions. Nevertheless, only three athletes (2%), all of them from the 24MTB, consumed NSAID during the race and 5% of all mountain bikers reported consumption after the race. In contrast to the SMTB, the intake reported by the 24MTB participants was quite homogeneous in terms of the timing of NSAID consumption. The NSAID users were older (p = 0.043) than the non-users. Ibuprofen was most commonly used by 79% of all consumers.

Conclusion: The prevalence of NSAID use was higher in the older participants and seems to be lower in comparison with results from studies about runners, ultra-runners and triathletes suggesting that it is determined by the discipline (i.e., cycling). On the other hand, the timing of NSAID consumption was probably affected by the competition character (e.g., MTBS or 24MTB). Future studies should focus on a larger sample size of cyclists from various disciplines.

Strategies to decrease oxidative stress biomarker levels in human medical conditions: A meta-analysis on 8-iso-prostaglandin F2α

The widespread detection of elevated oxidative stress levels in many medical conditions has led to numerous efforts to design interventions to reduce its effects. Efforts have been wide-ranging, from dietary changes to administration of antioxidants, supplements, e.g., omega-3-fatty acids, and many medications. However, there is still no systemic assessment of the efficacy of treatments for oxidative stress reduction across a variety of medical conditions. The goal of this meta-analysis is, by combining multiple studies, to quantitate the change in the levels of the popular oxidative stress biomarker 8-iso-prostaglandin F2α (8-iso-PGF2α) after a variety of treatment strategies in human populations. Nearly 350 unique publications with 180 distinct strategies were included in the analysis. For each strategy, the difference between pre- or placebo and post-treatment levels calculated using Hedges' g value of effect. In general, administration of antibiotics, antihyperlipidemic agents, or changes in lifestyle (g = - 0.63, - 0.54, and 0.56) had the largest effect. Administration of supplements, antioxidants, or changes in diet (g = - 0.09, - 0.28, - 0.12) had small quantitative effects. To fully interpret the effectiveness of these treatments, comparisons to the increase in g value for each medical condition is required. For example, antioxidants in populations with coronary artery disease (CAD) reduce the 8-iso-PGF2α levels by g = - 0.34 ± 0.1, which is quantitatively considered a small effect. However, CAD populations, in comparison to healthy populations, have an increase in 8-iso-PGF2α levels by g = 0.38 ± 0.04; therefore, the overall reduction of 8-iso-PGF2α levels is ≈ 90% by this treatment in this specific medical condition. In conclusion, 8-iso-PGF2α levels can be reduced not only by antioxidants but by many other strategies. Not all strategies are equally effective at reducing 8-iso-PGF2α levels. In addition, the effectiveness of any strategy can be assessed only in relation to the medical condition investigated.

A randomized controlled trial of manual therapy and pneumatic compression for recovery from prolonged running - an extended study

Manual therapy (MT) and intermittent pneumatic compression (IPC) are recovery methods used by endurance athletes with little evidence supporting effectiveness. This randomized controlled trial evaluated effectiveness of four daily post-race treatments of a specific MT protocol and IPC compared with supine rest on recovery following an ultramarathon among 56 ultramarathoners. Groups were comparable across all characteristics examined, including post-race plasma creatine kinase concentration. Subject completed timed 400 m runs before the race and on days three, five, seven and 14 post- race, and also provided muscle pain and soreness ratings and fatigue scores immediately before and after treatments, and during the 14 days post- race. Daily subjective measures and 400 m run times were not improved by either treatment, but both treatments reduced (p < .05) muscular fatigue scores acutely after treatment following the race and on post-race day 1, and MT improved (p < .05) muscle pain and soreness acutely following the race.

ANTI-ULCEROGENIC EFFICACY AND MECHANISMS OF EDIBLE AND NATURAL INGREDIENTS IN NSAID-INDUCED ANIMAL MODELS

Background:

Nonsteroidal anti-inflammatory drugs (NSAIDs) are a class of the most commonly used medicines and proven to be effective for certain disorders. Some people use NSAIDs on daily basis for preventive purpose. But a variety of severe side effects can be induced by NSAIDs. Studies have shown that edible natural ingredients exhibit preventive benefit of gastric ulcer. This paper reviews the efficacy and safety of edible natural ingredients in preventing the development of gastric ulcer induced by NSAIDs in animal models.

Methods:

A systematic literature search was conducted on PubMed, using the terms “herbal medicines” and “gastric ulcer”, “herbal medicines” and “peptic ulcer”, “food” and “peptic ulcer”, “food” and “gastric ulcer”, “natural ingredient” and “peptic ulcer”, “natural ingredient” and “gastric ulcer”, “alternative medicine” and “peptic ulcer”, “alternative medicine” and “gastric ulcer”, “complementary medicine” and “peptic ulcer”, “complementary medicine” and “gastric ulcer” in papers published in English between January 1, 1960 and January 31, 2016, resulting in a total of 6146 articles containing these terms. After exclusion of studies not related prevention, not in NSAID model or using non-edible natural ingredients, 54 articles were included in this review.

Results:

Numerous studies have demonstrated that edible natural ingredients exhibit antiulcerogenic benefit in NSAID-induced animal models. The mechanisms by which edible, ingredient-induced anti-ulcerogenic effects include stimulation of mucous cell proliferation, antioxidation, inhibition of gastric acid secretion, as well as inhibition of H (+), K (+)- ATPase activities. Utilization of edible, natural ingredients could be a safe, valuable alternative to prevent the development of NSAID-induced gastric ulcer, particularly for the subjects who are long-term users of NSAIDs.

A Placebo-Controlled Trial of Riboflavin for Enhancement of Ultramarathon Recovery

Background

Riboflavin is known to protect tissue from oxidative damage but, to our knowledge, has not been explored as a means to control exercise-related muscle soreness. This study investigated whether acute ingestion of riboflavin reduces muscle pain and soreness during and after completion of a 161-km ultramarathon and improves functional recovery after the event.

Methods

In this double-blind, placebo-controlled trial, participants of the 2016 161-km Western States Endurance Run were assigned to receive a riboflavin or placebo capsule shortly before the race start and when reaching 90 km. Capsules contained either 100 mg of riboflavin or 95 mg of maltodextrin and 5 mg of 10% ß-carotene. Subjects provided muscle pain and soreness ratings before, during, and immediately after the race and for the 10 subsequent days. Subjects also completed 400-m runs at maximum speed on days 3, 5, and 10 after the race.

Results

For the 32 (18 in the riboflavin group, 14 in the placebo group) race finishers completing the study, muscle pain and soreness ratings during and immediately after the race were found to be significantly lower (p = .043) for the riboflavin group. Analysis of the 400-m run times also showed significantly faster (p < .05) times for the riboflavin group than the placebo group at post-race days 3 and 5. Both groups showed that muscle pain and soreness had returned to pre-race levels by 5 days after the race and that 400-m run times had returned to pre-race performance levels by 10 days after the race.

Conclusions

This preliminary work suggests that riboflavin supplementation before and during prolonged running might reduce muscle pain and soreness during and at the completion of the exercise and may enhance early functional recovery after the exercise.

Determinants of recovery from a 161-km ultramarathon

The primary study objective was to identify determinants of short-term recovery from a 161-km ultramarathon. Participants completed 400 m runs at maximum speed before the race and on days 3 and 5 post-race, provided a post-race blood sample for plasma creatine kinase (CK) concentration, and provided lower body muscle pain and soreness ratings (soreness, 10-point scale) and overall muscular fatigue scores (fatigue, 100-point scale) pre-race and for 7 days post-race. Among 72 race finishers, soreness and fatigue had statistically returned to pre-race levels by 5 days post-race; and 400 m times at days 3 and 5 remained 26% (P = 0.001) and 12% (P = 0.01) slower compared with pre-race, respectively. CK best modelled soreness, fatigue and per cent change in post-race 400 m time. Runners with the highest CKs had 1.5 points higher (P < 0.001) soreness and 11.2 points higher (P = 0.006) fatigue than runners with the lowest CKs. For the model of 400 m time, a significant interaction of time with CK (P < 0.001) indicates that higher CKs were linked with a slower rate of return to pre-race 400 m time. Since post-race CK was the main modifiable determinant of recovery following the ultramarathon, appropriate training appears to be the optimal approach to enhance ultramarathon recovery.

A Randomized Controlled Trial of Massage and Pneumatic Compression for Ultramarathon Recovery

Study Design Randomized controlled trial. Background Postexercise recovery techniques are widely used, but little research has examined their effectiveness. Objectives To examine the effectiveness of massage and pneumatic compression on recovery from a 161-km ultramarathon. Methods Participants in the 2015 161-km Western States Endurance Run were randomized to a 20-minute postrace intervention of massage, intermittent sequential pneumatic compression, or supine rest. Each subject completed two 400-m runs at maximum speed before the race and on days 3 and 5 after the race, and also provided muscle pain and soreness ratings and overall muscular fatigue scores before and for 7 days after the race. Results Among the 72 runners who finished the race and completed the study, comparison among intervention groups revealed no significant group or interaction effect on 400-m run time, but there was a significant (P<.0001) time effect. Immediately posttreatment, massage resulted in lower muscle pain and soreness ratings compared with the supine-rest control condition (P<.0001), while both massage (P<.0001) and pneumatic compression (P<.01) resulted in lower overall muscular fatigue scores compared with the control group. There were no significant differences between groups in any outcome 1 to 7 days after the race. Conclusion Single 20-minute sessions of postrace massage and intermittent sequential pneumatic compression provide some immediate subjective benefit. There is no evidence, however, that such treatments provide extended subjective or functional benefits of clinical importance. The trial was registered at www.clinicaltrials.gov (NCT02530190). Level of Evidence Therapy, level 1b. J Orthop Sports Phys Ther 2016;46(5):320-326. Epub 23 Mar 2016. doi:10.2519/jospt.2016.6455.

Alterations in redox homeostasis in the elite endurance athlete

BACKGROUND

The production of reactive oxygen (ROS) and nitrogen species (RNS) is a fundamental feature of mammalian physiology, cellular respiration and cell signalling, and essential for muscle function and training adaptation. Aerobic and anaerobic exercise results in alterations in redox homeostasis (ARH) in untrained, trained and well trained athletes. Low to moderate doses of ROS and RNS play a role in muscle adaptation to endurance training, but an overwhelming increase in RNS and ROS may lead to increased cell apoptosis and immunosuppression, fatigued states and underperformance.

OBJECTIVES

The objectives of this systematic review are: (a) to test the hypotheses that ARH occur in elite endurance athletes; following an acute exercise bout, in an endurance race or competition; across a micro-, meso- or macro-training cycle; following a training taper; before, during and after altitude training; in females with amenorrhoea versus eumenorrhoea; and in non-functional over-reaching (NFOR) and overtraining states (OTS); (b) to report any relationship between ARH and training load and ARH and performance; and (c) to apply critical difference values for measures of oxidative stress/ARH to address whether there is any evidence of ARH being of physiological significance (not just statistical) and thus relevant to health and performance in the elite athlete.

METHODS

Electronic databases, Embase, MEDLINE, and SPORTDiscus were searched for relevant articles. Only studies that were observational articles of cross-sectional or longitudinal design, and included elite athletes competing at national or international level in endurance sports were included. Studies had to include biomarkers of ARH; oxidative damage, antioxidant enzymes, antioxidant capacity, and antioxidant vitamins and nutrients in urine, serum, plasma, whole blood, red blood cells (RBCs) and white blood cells (WBCs). A total of 3,057 articles were identified from the electronic searches. Twenty-eight articles met the inclusion criteria and were included in the review.

RESULTS

ARH occurs in elite endurance athletes, after acute exercise, a competition or race, across training phases, and with natural or simulated altitude. A reduction in ARH occurs across the season in elite athletes, with marked variation around intensified training phases, between individuals, and the greatest disturbances (of physiological significance) occurring with live-high-train-low techniques, and in athletes competing. A relationship with ARH and performance and illness exists in elite athletes. There was considerable heterogeneity across the studies for the biomarkers and assays used; the sport; the blood sampling time points; and the phase in the annual training cycle and thus baseline athlete fitness. In addition, there was a consistent lack of reporting of the analytical variability of the assays used to assess ARH.

CONCLUSIONS

The reported biochemical changes around ARH in elite athletes suggest that it may be of value to monitor biomarkers of ARH at rest, pre- and post-simulated performance tests, and before and after training micro- and meso-cycles, and altitude camps, to identify individual tolerance to training loads, potentially allowing the prevention of non-functionally over-reached states and optimisation of the individual training taper and training programme.

Massage timing affects postexercise muscle recovery and inflammation in a rabbit model

PURPOSE

This study compared the effect of immediate versus delayed massage-like compressive loading (MLL) on peak isometric torque recovery and inflammatory cell infiltration after eccentric exercise (EEX).

METHODS

Eighteen skeletally mature New Zealand White rabbits were instrumented with peroneal nerve cuffs for the stimulation of hindlimb tibialis anterior muscles. After a bout of EEX, rabbits were randomly assigned to an MLL protocol (0.5 Hz, 10 N, 15 min) that started immediately post-EEX, 48 h post-EXX, or no-MLL control and performed for four consecutive days. A torque-angle (T-Θ) relationship was obtained for 21 joint angles pre- and post-EEX and after four consecutive days of MLL or no-MLL. Muscle wet weights and immunohistochemical sections were obtained after final treatments.

RESULTS

EEX produced an average 51% ± 13% decrease in peak isometric torque output. The greatest peak torque recovery occurred with the immediate application of MLL. There were differences in torque recovery between immediate and delayed MLL (P = 0.0012), immediate MLL and control (P < 0.0001), and delayed MLL and control (P = 0.025). Immunohistochemical analysis showed 39.3% and 366.0% differences in the number of RPN3/57 and CD11b-positive cells between immediate (P = 0.71) and delayed MLL (P = 0.12). The area under the T-Θ curve showed a difference for immediate (P < 0.0001) and delayed (P = 0.0051) MLL as compared with control. Exercise produced an average 10° ± 0.2° rightward shift from preexercise peak isometric torque angle. Control, immediate MLL, and delayed MLL produced an average leftward angular shift from the postexercise angle (P = 0.28, P = 0.03, and P = 0.47, respectively).

CONCLUSION

Post-EEX, immediate MLL was more beneficial than delayed MLL in restoring muscle function and in modulating inflammatory cell infiltration. These findings invite similar human studies to make definitive conclusions on optimal timing of massage-based therapies.

Influence of a low-dose cox-2 inhibitor drug on exercise-induced inflammation, muscle damage and lipid peroxidation

The purpose of this study was to examine the effect of acute low-dose celecoxib administration on exercise-induced inflammation, muscle damage and lipid peroxidation. Twenty healthy untrained males (age: 25.5±4.5 yrs, weight: 72.7±7.9 kg, height: 177.3±7.2 cm) were randomly assigned to treatment (T) or placebo (P) groups. Blood samples were obtained before, immediately after, 3 h after and 24 h after exercise. Subjects ran for 30 min at 75% V.O₂ max on a treadmill. Participants consumed 100 mg celecoxib or a placebo immediately after and 12 h after the immediately post-exercise blood sample. Total leukocytes, neutrophils, creatine kinase (CK), C-reactive protein (CRP) and malondialdehyde (MDA) were assessed at each time point. Significant increases in total leukocytes and neutrophils were observed 3 h after exercise in both groups (P < 0.05). CK and CRP levels were significantly increased immediately, 3 h and 24 h after exercise in both groups (P < 0.05). A significant increase in MDA was observed immediately after exercise in both groups (P < 0.05); however, no significant group differences were observed for MDA or CK. These findings suggest that inhibition of cyclo-oxygenase activity with low-dose celecoxib does not affect exercise-induced inflammation, muscle damage, or lipid peroxidation.

Urine dipstick analysis for identification of runners susceptible to acute kidney injury following an ultramarathon

This study examined whether urine dipstick testing might be useful to predict the development of acute kidney injury after an ultramarathon. Participants in the 2011 161-km Western States Endurance Run underwent post-race blood and urine dipstick analyses. Of the 310 race finishers, post-race urine dipstick testing was completed on 152 (49%) and post-race blood also was obtained from 150 of those runners. Based on "injury" and "risk" criteria for acute kidney injury of blood creatinine 2.0 and 1.5 times estimated baseline, respectively, 4% met the criteria for injury and an additional 29-30% met the criteria for risk of injury. Those meeting the injury criteria had higher creatine kinase concentrations (P < 0.001) than those not meeting the criteria. Urine dipstick tests that read positive for at least 1+ protein, 3+ blood, and specific gravity ≥ 1.025 predicted those meeting the injury criteria with sensitivity of 1.00 (95% confidence interval [CI] 0.54-1.00), specificity of 0.76 (95% CI 0.69-0.83), positive predictive value of 0.15 (95% CI 0.06-0.30), negative predictive value of 1.00 (95% CI 0.97-1.00), and likelihood ratio for a positive test of 4.2. We conclude that urine dipstick testing was successfully able to identify those individuals meeting injury criteria for acute kidney injury with excellent sensitivity and specificity.

Factors related to successful completion of a 161-km ultramarathon

PURPOSE

Despite increased 161-km ultramarathon participation in recent years, little is known about those who pursue such an activity. This study surveyed entrants in two of the largest 161-km trail ultramarathon runs in North America to explore demographic characteristics and issues that affected race performance.

METHODS

All entries of the 2009 Western States Endurance Run and the Vermont 100 Endurance Race were invited to complete a postrace questionnaire.

RESULTS

There were 500 respondents among the 701 race entries (71.3% response). Finish time was found to have a significant (P ≤ .01) negative association with training volume and was generally directly associated with body mass index. Among nonfinishers, the primary reason for dropping out was nausea and/or vomiting (23.0%). Finishers compared with nonfinishers were more likely (P ≤ .02) to report blisters (40.1% vs 17.3%), muscle pain (36.5% vs 20.1%), and exhaustion (23.1% vs 13.7%) as adversely affecting race performance, but nausea and/or vomiting was similar between groups (36.8% vs 39.6%). Nausea and/or vomiting was no more common among those using nonsteroidal anti-inflammatory drugs (NSAIDs), those participating in the event with higher ambient temperatures, those with a lower training volume, or those with less experience at finishing 161-km races. Overall use of NSAIDs was high, and greater (P = .006) among finishers (60.5%) than nonfinishers (46.4%).

CONCLUSIONS

From this study, we conclude that primary performance-limiting issues in 161-km ultramarathons include nausea and/or vomiting, blisters, and muscle pain, and there is a disturbingly high use of NSAIDs in these events.

Cyclic compressive loading facilitates recovery after eccentric exercise

PURPOSE

To assess the biologic basis of massage therapies, we developed an experimental approach to mimic Swedish massage and evaluate this approach on recovery from eccentric exercise-induced muscle damage using a well-controlled animal model.

METHODS

Tibialis anterior muscles of six New Zealand White rabbits were subjected to one bout of damaging, eccentric contractions. One muscle was immediately subjected to cyclic compressive loads, and the contralateral served as the exercised control.

RESULTS

We found that commencing 30 min of cyclic compressive loading to the muscle, immediately after a bout of eccentric exercise, facilitated recovery of function and attenuated leukocyte infiltration. In addition, fiber necrosis and wet weight of the tissue were also reduced by compressive loading.

CONCLUSION

We conclude that subjecting muscle to compressive loads immediately after exercise leads to an enhanced recovery of muscle function and attenuation of the damaging effects of inflammation in the rabbit model. Although these observations suggest that skeletal muscle responds to cyclic compressive forces similar to those generated by clinical approaches, such as therapeutic massage, further research is needed to assess the translational efficacy of these findings.