Sports Physiology Research Articles

АДАПТИВНЫЕ БИОХИМИЧЕСКИЕ ИЗМЕНЕНИЯ ЭРИТРОЦИТОВ КРЫСЫ ПОСЛЕ ЦИКЛА ПРИНУДИТЕЛЬНОГО ПЛАВАНИЯ С ПРИМЕНЕНИЕМ ЭКСТРАКТА ЗЕЛЕНОГО ЧАЯ И АММОНИЙНОГО ПРЕКОНДИЦИОНИРОВАНИЯ

The study of natural compounds, increasing endurance and (or) accelerating recovery, is the most important task of sports medicine and physiology. This paper presents the results of comparing the effects of decaffeinated green tea extract (GTE) and one of the endogenous products of amino acid metabolism, ammonia, which was tested as a solution of ammonium chloride (NH4Cl) alone and in combination with GTE as a stimulator of physical performance. In a forced swimming model, the stimulating effect of NH4Cl was established, which exceeded the action of GTE. Multidirectional adaptive changes of some biochemical parameters of blood plasma and erythrocytes were revealed in rats using GTE and NH4Cl, as well as enhancing effect of combined application of these compounds on the performance of rats. A mechanism is proposed for optimizing the oxygen transport and shuttle function of erythrocytes by ammonium chloride under conditions of intense physical activity.

Pre-exercise optimisation of the alkalosis response to sodium bicarbonate ingestion: have we been missing its peak ergogenic effect?

The use of sodium bicarbonate (NaHCO 3 ) as an ergogenic aid has been widespread in athletic populations where high intensity, relatively short duration activity, is an important component of performance. The traditional ingestion time for this pre-exercise ergogenic buffering agent, is typically between 60-120 minutes before the start of exercise, using the most frequently ingested dose of 300 mg.kgBM -1 (McNaughton et al., 2016). This strategy has provided some equivocal data regarding the efficacy of the use of NaHCO 3 , in some sporting activities (Carr et al., 2012). However, a recent innovation using a personalised approach to the pre-exercise ingestion timing for NaHCO 3 (Miller et al., 2016; Sparks et al., 2017), may be more appropriate to achieve optimal ergogenic effects. The use of this technique has been shown to produce repeatable acid-base (Gough et al., 2017a) and performance responses (Gough et al., 2017b). More specifically, an individualised approach that synchronises the start of exercise with peak HCO 3 concentrations, appears to produce more consistent performance advantages over placebos in exercise bouts like 4 km cycling time trials (TT). This approach still suggests that doses of 300 mg.kgBM -1 are likely to be more ergogenic than 200 mg.kgBM -1 ones, but the associated gastrointestinal (GI) side effects that are exhibited in some athletes using higher doses may be ergolytic in extreme cases (Deb et al., 2018). Indeed, the GI symptoms are both difficult to predict and may vary between trials even with normal pre-exercise experimental dietary controls in place. Athletes, coaches, and performance nutrition professionals should therefore be aware of the potential ergogenic effect of NaHCO 3 , when individual time to peak has been accurately established, because it is likely larger than previously observed. However, caution and careful familiarisation with this ergogenic aid is essential to determine the severity of the potential ergolytic side effects that may preclude athletes from using it. Â Keywords: Ergogenic aid, performance, nutritional intervention, supplement. Â References Carr AJ, Slater GJ, Gore CJ, Dawson B, Burke LM (2012) Reliability and effect of sodium bicarbonate: buffering and 2000-m rowing performance. International Journal of Sports Physiology and Performance 7 (2):152-60. doi: 10.1123/ijspp.7.2.152 Â Deb SK, Gough LA, Sparks SA, McNaughton LR (2018) Sodium bicarbonate supplementation improves severe-intensity intermittent exercise under moderate acute hypoxic conditions. European Journal of Applied Physiology 118 (3):607-615 . doi: 10.1007/s00421-018-3801-7. Â Gough L, Deb S, Sparks SA, McNaughton LR (2017a) The Reproducibility of Blood Acid Base Responses in Male Collegiate Athletes Following Individualised Doses of Sodium Bicarbonate: A Randomised Controlled Crossover Study. Sports Medicine 47 (10):2117-2127. doi: 10.1007/s40279-017-0699-x. Â Gough L, Deb SK, Sparks SA, McNaughton LR (2017b) The reproducibility of 4 km time trial (TT) performance following individualised sodium bicarbonate supplementation: a randomised controlled trial in trained cyclists. Sports Medicine Open 3 (1) :34. doi: 10.1186/s40798-017-0101-4. Â McNaughton LR, Gough L, Deb S, Bentley D, Sparks SA (2016) Recent developments in the use of sodium bicarbonate as an ergogenic aid. Current Sports Medicine Reports 15 (4):233-44. doi: 10.1249/JSR.0000000000000283. Â Miller P, Robinson A, Sparks SA, Bridge CA, Bentley D, McNaughton LR (2016) The effects of novel ingestion of sodium bicarbonate on repeated sprint ability. Journal of Strength and Conditioning Research. 30 (2): 561-568. doi: 10.1519/JSC.0000000000001126. Â Sparks SA, Williams EL, Bentley D, Bridge CA, McNaughton LR (2017) Sodium bicarbonate ingestion and individual variability in time to peak pH. Research in Sports Medicine 25 (1):58-66. doi: 10.1080/15438627.2016.1258645.

Measurement of metabolic fluxes using stable isotope tracers in whole animals and human patients.

Metabolic flux analysis using stable isotope labeled substrates allows for the tracing of carbon, nitrogen, and hydrogen atoms through metabolic pathways and is an invaluable tool for investigating dynamic metabolic changes occurring in health and disease. Studies of flux analysis in vivo are more technically challenging than in vitro or ex vivo but provide a highly detailed view of organ and/or systemic metabolism. We review here recent efforts in studies of diet and nutrition, non-small cell lung cancer, ischemia/reperfusion injury, and hemorrhagic shock where in vivo flux analysis was utilized to analyze metabolic modulation. Recent technical strides in the field of metabolomics afford sensitive and quantitative in vivo measurements of metabolic fluxes. Stable isotope tracing with C-glucose, C, N-glutamine, C-propionate, and other substrates are used in combination or in parallel to investigate the interplays among central carbon metabolic pathways and many other areas of the metabolome. Stable isotope tracing in vivo provides opportunities to investigate physiological processes in the context of the whole animal. These approaches, often NMR spectroscopy or mass spectrometry (MS)-based, are growing in use and will likely find key applications in studying systemic disease, sports physiology, cancer metabolism, and personalized medicine.

Gazelle: Energy-Efficient Wearable Analysis for Running

Running is one of the most popular sports with hundreds of millions of participants worldwide. Good running form is the key to fast, efficient, and injury-free running. Existing kinematic analysis technologies, such as high-speed camera systems, are expensive, difficult to operate, and exclusive to sports physiology laboratories and elite athletes. Miniature MEMS-based motion sensors enable portable high-precision kinematic analysis, but suffer from high energy consumption hence short battery lifetime, especially for continued online analysis for running. This paper presents Gazelle, a wearable online analysis system for running that is compact, lightweight, accurate, and highly energy efficient; intended for runners of all levels. To enable long-term maintenance-free mobile analysis for running, Sparse Adaptive Sensing (SAS) is proposed, which selectively identifies the best sampling points to maintain high accuracy while greatly reducing sensing and analysis energy overheads. Experimental results demonstrate 97.7 percent accuracy with 76.9 to 99 percent reduced energy consumption (83.6 percent average reduction under real-world testing)-a one-order-of-magnitude improvement over existing solutions. SAS enables $>$ 200 days of continuous high-precision operation using only a coin-cell battery. Since 2014, Gazelle has been used by over 100 elite and recreational runners during daily training and at top-level races like the Kona Ironman World Championships and New York Marathon.

Specific circulating phospholipids, acylcarnitines, amino acids and biogenic amines are aerobic exercise markers.

Regular aerobic exercise provides beneficial effects on human health and reduces all-cause mortality. Aerobic exercise has profound metabolic effects, and specific metabolites may reflect physiological changes. We aimed to identify endogenous metabolites that distinguish the trained from the untrained state to increase the spectrum of analytes amenable for hypothesis testing and to expand understanding of putative beneficial pathways. Cross sectional laboratory repeated measures study. Exercise testing was performed in 37 healthy male participants and serum samples were obtained before and after completion of a ten-week standardized exercise program. Samples were analyzed for routine clinical parameters and for 188 endogenous metabolites by LC-MS/MS. Indicating the effectiveness of the intervention program, parameters of sport physiology were different after training. After correcting for multiple testing, serum concentrations of several metabolites differed between the trained and untrained state. Serine and glutamate decreased in response to exercise, whereas sarcosine and kynurenine increased. Phosphatidylcholines showed a mixed response in that four species increased and three decreased. However, all seven lysophosphatidylcholines and all four plasmalogens that differed between the trained and untrained state, increased. One short-chain acylcarnitine also decreased. In receiver operator characteristics analyses, sarcosine displayed the highest AUC value (0.839; 95% CI: 0.734-0.926) in discriminating the pre- from the post-trained state. Our study detected metabolites that clearly differentiate the trained from the untrained state. These metabolites may be targeted in mechanistic studies to understand underlying biochemical pathways and could serve to improve the design, monitoring and individualization of training programs.

An overview and recommendations for using expired gas analysis indirect calorimetry in professional practice and research

Introduction: The prior presentations and abstracts have provided detailed accounts of the fundamental concepts and equations of the method, compared different methods of measuring ventilation, and also compared different methods of expired gas sampling and analysis. Important features of EGAIC have been highlighted, and several concerns have been raised based on past and current practice. The purpose of this presentation is to provide a concise overview of these findings, and establish the needed changes that need to be made to current practice to improve the internal and external validity of the method. These changes will be presented as a series of recommendations linked to strategies that can be followed to ensure that such changes can occur with minimal expense but maximal impact. In addition, key aspects of future research will be identified that if pursued will provide further improvements to the validity of EGAIC and its correct applications to sport physiology, nutrition, and the detection, prevention and rehabilitation from disease.

The integrated assessment of the functional status of soccer players in different periods of football season

The search for simple and minimally invasive methods of diagnostics of the functional status of professional soccer players was always the object of the interest of sport medicine and physiology. The aim of research was the increase of medical control of the professional soccer players by elaboration and introduction of methodology of integral assessment of the soccer players’ functional status using the program-hardware complex Fazagraf ® . Methods of research. The research included 34 professional players in the age 18-34 years. The research was carried out during the football season in different training periods and included instrumental methodology of assessment of the functional status using apparatus fazagraf and also the methodology of assessment of the functional status, offered by us. Results of research. With the help of the offered methodology it was established, that at the end of basic period the low marks of FS (1,2 and 3) were not fixed. All soccer players were in the good and very good FS. At the end of competitive period of training it was revealed, that in 11 soccer players (32%) were observed the low indices of integral assessment that is FS disorders. Conclusion: in the basic period of training takes place the increase of adaptive potential and decrease of the risk of development of disorders in sportsmen’s health. In competitive period of training were observed the disorders of functional status under the effect of big physical loads and other factors that needs more attention to the medical control in this training period

Surveillance technologies as Instruments of discipline in the elite sports coaching context: A cautionary post-structural commentary

The use of surveillance technologies as tools to encourage performance enhancement has become an accepted component of elite coaching. Those from the communities of sports physiology, psychology and biomechanics who promote the application of surveillance technologies have reported multiple benefits for the athlete. Conversely, several socio-cultural studies have suggested that surveillance technologies can lead to an oppressive mechanism of control over the athlete, significantly altering the role and responsibilities of the contemporary coach. In this critical commentary we use a post-structural position and adopt Foucault’s disciplinary analysis to contribute to the ongoing debate surrounding the use of surveillance technology in sport. Specifically, we achieve this by labelling surveillance technologies in sport as what Foucault (1977) might call, instruments of discipline, and by explaining the impact they have upon the working coach and the skilled athlete. We present some suggestions surrounding how to most appropriately utilise surveillance technologies in a sports coaching context and conclude by warning against a binary consideration of the use of technology as either good or bad.

Effect of shoes cleat position on physiological and biomechanical variables of cycling performance

Introduction: The cleat under the cycling shoe is generally positioned below the first metatarsal head, directly over the pedal axis (Silberman et al., 2005, Clinical Journal of Sport Medicine, 15, 271-276). Previous studies did not found significant change of oxygen consumption (VO2) with moving forward or backward the cleat position (Van Sickle & Hull, 2007, Journal of Biomechanics, 40, 1262-1267; Paton, 2009, International Journal of Sports Physiology and Performance, 4, 517-523) although small changes in electromyography (EMG) activity in leg and thigh muscles have been observed (Ericson et al., 1985, Scandinavian Journal of Rehabilitation Medicine, 17, 53-61; Litzenberger et al., 2008, The Engineering of Sport 7, 1, 215-222). However, these changes have been observed with non cyclist subjects for larger shoe cleat displacements (+ 50 mm).  Purpose: The aim of this study was to investigate the acute effects of small variation of cleat position on the energy cost and pedalling technique (kinetics, kinematics and electromyography) during submaximal cycling. The second purpose was to analyze their effects on supramaximal cycling performance.  Methods: Twelve cyclists participated (25 ± 6 years; 69 ± 7 kg; 1.78 ± 0.05 m; Maximal Aerobic Power: 406 ± 40 W), being amateur and elite cyclists, according to previous conventions (Ansley and Cangley, 2009, European Journal of Sport Science, 9(2), 61-85). They performed three 5-min submaximal pedalling exercises (35, 50 and 65% MAP) and one 10-s supramaximal test (sprint) on Lode Excalibur electromagnetically braked cycle ergometer (Lode B. V., Groningen, The Netherlands). Three different cleat positions were studied in a randomized order: under the first metatarsal head, 15 mm forward and 15 mm backward. Power output, oxygen consumption, kinematics of lower limb joints and surface EMG activity (EMG) of six lower limb muscles (rectus femoris: RF, vastus lateralis: VL, biceps femoris: BF, tibialis anterior: TA, gastrocnemius lateralis: GL, soleus: SOL) were recorded during all the pedalling exercises, at 1, breath-by-breath, 200 and 1000 Hz, respectively. The kinematics and RMS over whole crank cycle of EMG activity were computed during 30 consecutives pedalling cycles. One-way ANOVA for repeated measures was performed to analyse the effect of cleat position on biomechanical and physiological variables.   Results and Discussion: Hip ROM was lower in forward position and ankle ROM was lower in backward position compared to the metatarsal position (Figure 1). None significant differences between the three cleat positions were found for knee ROM and RMS despite trends can be observed in backward position for SOL and GL activity to decrease and for RF and TA activity to increase. These tendencies are consistent with previous studies (Ericson et al., 1985; Litzenberger et al., 2008). Like in previous studies (Van Sickle & Hull, 2007; Paton, 2009), small changes of cleat position had no significant effects on VO2, nor on gross efficiency (19.9 ± 1.9 % ; 19.5 ± 2.1 % ;19.4 ± 2.0 % respectively for forward, metatarsal and backward cleat positions). No significant differences in peak power output were found during the supramaximal test between forward (18.9 ± 3.2 W.kg-1), metatarsal (19.0 ± 3.4 W.kg-1) and backward (19.0 ± 2.9 W.kg-1) cleat positions.  To conclude, the main finding of this study is that small changes of cleat position (± 15 mm) involve slight changes of kinematic of the hip and ankle joints without altering cycling efficiency and maximal power output during supramaximal sprints. Although muscular activity level remains unchanged by variation ± 15 mm of cleat position, these results should be completed by the analysis of the muscle timing activation.

Scientific Progress or Regress in Sports Physiology?

In modern societies there is strong belief in scientific progress, but, unfortunately, a parallel partial regress occurs because of often avoidable mistakes. Mistakes are mainly forgetting, erroneous theories, errors in experiments and manuscripts, prejudice, selected publication of "positive" results, and fraud. An example of forgetting is that methods introduced decades ago are used without knowing the underlying theories: Basic articles are no longer read or cited. This omission may cause incorrect interpretation of results. For instance, false use of actual base excess instead of standard base excess for calculation of the number of hydrogen ions leaving the muscles raised the idea that an unknown fixed acid is produced in addition to lactic acid during exercise. An erroneous theory led to the conclusion that lactate is not the anion of a strong acid but a buffer. Mistakes occur after incorrect application of a method, after exclusion of unwelcome values, during evaluation of measurements by false calculations, or during preparation of manuscripts. Co-authors, as well as reviewers, do not always carefully read papers before publication. Peer reviewers might be biased against a hypothesis or an author. A general problem is selected publication of positive results. An example of fraud in sports medicine is the presence of doped subjects in groups of investigated athletes. To reduce regress, it is important that investigators search both original and recent articles on a topic and conscientiously examine the data. All co-authors and reviewers should read the text thoroughly and inspect all tables and figures in a manuscript.

Specific circulating phospholipids, acylcarnitines, amino acids and biogenic amines are aerobic exercise markers

Abstract Objectives Regular aerobic exercise provides beneficial effects on human health and reduces all-cause mortality. Aerobic exercise has profound metabolic effects, and specific metabolites may reflect physiological changes. We aimed to identify endogenous metabolites that distinguish the trained from the untrained state to increase the spectrum of analytes amenable for hypothesis testing and to expand understanding of putative beneficial pathways. Design Cross sectional laboratory repeated measures study. Methods Exercise testing was performed in 37 healthy male participants and serum samples were obtained before and after completion of a ten-week standardized exercise program. Samples were analyzed for routine clinical parameters and for 188 endogenous metabolites by LC–MS/MS. Results Indicating the effectiveness of the intervention program, parameters of sport physiology were different after training. After correcting for multiple testing, serum concentrations of several metabolites differed between the trained and untrained state. Serine and glutamate decreased in response to exercise, whereas sarcosine and kynurenine increased. Phosphatidylcholines showed a mixed response in that four species increased and three decreased. However, all seven lysophosphatidylcholines and all four plasmalogens that differed between the trained and untrained state, increased. One short-chain acylcarnitine also decreased. In receiver operator characteristics analyses, sarcosine displayed the highest AUC value (0.839; 95% CI: 0.734–0.926) in discriminating the pre- from the post-trained state. Conclusions Our study detected metabolites that clearly differentiate the trained from the untrained state. These metabolites may be targeted in mechanistic studies to understand underlying biochemical pathways and could serve to improve the design, monitoring and individualization of training programs.

State of the Science-Ultraendurance Sports.

Participation in ultraendurance sports has been increasing in recent years. This participation growth has been associated with an increase in research focused on such events. While the total amount of research related to these sports remains relatively small compared with other sports, the research growth is encouraging. New sources for research funding for ultraendurance sports should advance the science. In addition to continued opportunities with observational studies, promising areas of investigation remain for experimental studies and research that uses ultraendurance-sport environments as models for studies relevant to wider populations. Insight into the breadth of research opportunities in ultraendurance sports can be gained by reviewing the abstracts published online in the International Journal of Sports Physiology and Performance from the annual Medicine & Science in Ultra-Endurance Sports Conference that took place this year in Chamonix, France.

Use of the Testosterone/Cortisol Ratio Variable in Sports

This critical review discusses the use of the testosterone/cortisol ratio in the studies of athletic performance and sports physiology. Although in most of the time physical exercise is beneficial to health, it can also be seen as a “stressor” both in men and in women. It is not completely known at what level this “physical stress” ends up its beneficial effects and begins to impair health status. In search for this putative turning point, several markers have been put forward in the last decades. One of these markers is the ratio between testosterone, considered as an anabolic hormone, and cortisol, considered as a catabolic one. Whether in search for an anabolic internal environment for strength training or to avoid performance decline during aerobic workout, the testosterone/cortisol ratio has been considered as an important physiological variable to gauge individual conditioning and responses.

Disciplinarity and sport science in Europe: A statistical and sociological study of ECSS conference abstracts

s of European College of Sports Science conferences (1995–2014) are studied. The number of abstracts has been increasing regularly (+90 per year). This rise is in recent years largely due to extra-European countries. The magnitude and accumulation of the different topics of discussion are examined. An operational criterion determines four stages of evolution of a topic: social network, cluster, specialty, and discipline. The scientific production can, therefore, be classified as disciplinary or non-disciplinary. The disciplinary part is more important but has been less dynamic recently. The cognitive content of sport science is then explored through a multidimensional scaling of the topics based on the keywords used in the abstracts. Three areas are visible: social sciences and humanities, sports medicine and physiology, and biomechanics and neurophysiology. According to the field theory of Bourdieu (1975), three scientific habitus are distinguished. The logic of academic disciplinary excellence is the consequence of the autonomy of this scientific field, its closure, peer-review process, and barriers to entry. The distribution of scientific capital and professional capital is unequal across the three areas. Basically, conservation strategies of academic disciplinary excellence are predicted in biomechanics and neurophysiology, subversion strategies of interdisciplinarity based on professional concerns can appear in the sports medicine and physiology area, and critical strategies of interdisciplinarity based on social utility in social sciences and humanities. Moreover, additional tensions within these areas are depicted. Lastly methods based on co-citations of disciplines and boundary objects are proposed to find tangible patterns of multidisciplinarity confirming these strategies.

The influence of footbolers functional status on the success in football competition

The search of the simple and minimally invasive methods of diagnostics of professional footballer functional state was always the subject of great interest of sport medicine and physiology. The aim of research was to reveal the connection between the indices of functional state and indices of the football player success in competition. Methods of research . The research included 28 football players – candidates to the national team of Ukraine less than 19 years old (U-19). The research was carried out during three matches of European Championship (U-19) and included the use of FAZAGRAF™ method for diagnostics of the functional state. This method is based on analysis of ascending and descending parts of T wave of the standard electrocardiogram and also attended with the change of heart rate variability for assessment of the state of vegetative nerve system and regulatory systems of organism. We carried out the expert assessment of effectiveness of competitive activity of footballers during the matches of tournament and also used the methods of mathematical statistics. Results of research . The index of integral assessment of success in the game during the tournament was in the mean 0,46±0,016. There was revealed a correlation between the functional state and the success in game. There were received adequate models for forecasting the success in game during the matches. Conclusion. The success of playing activity of footballers depends on their functional state the day before match. The most informative indices are rest pulse, symmetry of T wave and tension index according to Baevsky. With the help of received models it is possible to forecast the success of game of every footballer during the match. It helps trainer with the choice of players for the football match

The role of heart rate variability in sports physiology.

Heart rate variability (HRV) is a relevant marker reflecting cardiac modulation by sympathetic and vagal components of the autonomic nervous system (ANS). Although the clinical application of HRV is mainly associated with the prediction of sudden cardiac death and assessing cardiovascular and metabolic illness progression, recent observations have suggested its applicability to physical exercise training. HRV is becoming one of the most useful tools for tracking the time course of training adaptation/maladaptation of athletes and in setting the optimal training loads leading to improved performances. However, little is known regarding the role of HRV and the internal effects of physical exercise on an athlete, which may be useful in designing fitness programs ensuring sufficient training load that may correspond with the specific ability of the athlete. In this review, we offer a comprehensive assessment of investigations concerning the interrelation between HRV and ANS, and examine how the application of HRV to physical exercise may play a role in sports physiology.

Development and Implementation of Touch Screen Multimedia Technology in Sports Physiology Curriculum

With the advance of technological development, many emerging technologies have been successfully applied in the teaching field, resulting in significant improvements in teaching effects. However, applying these technologies to sports specialty teaching is difficult because of certain limitations of the specialty. Few trials have been made to reform teaching methods. This study analyzes innovative studies on existing sports teaching, points out shortcomings, and attempts to introduce touch screen multimedia technology in the sports specialty. This study also discusses the theoretical basis and supporting technology to construct touch screen multimedia teaching system, as well as the design and implementation of this system. The author applies this system in Sports Physiology teaching and designs a control experiment. Results show that the practical teaching effect of touch screen computer-assisted sports is superior to the traditional teaching method, and this technology offers a new teaching mode for sports teaching.

Fatigue in sport and exercise

Fatigue in sport has become a topic of interest among athletes, coaches and sport scientists because it affects athletic performance across a wide range of sports. Shaun Phillips is a sport physiology professor at the University of Edinburgh and has studied how peripheral and central mechanisms may impact fatigue. His text; Fatigue in Sport and Exercise, is the first book of its kind. Shaun synthesized a great deal of fatigue research into a go-to resource for those in the sport and exercise physiology field. Though his book does not provide “all the answers”, he presents the information and research in a way that’s easy to read and understand. Fatigue in Sport and Exercise is broken into four parts. Part 1 sheds light on the difficulty in defining fatigue and some of the ways in which fatigue is measured. Part 2 discusses many potential mechanisms of fatigue including metabolic acidosis, dehydration and hyperthermia, etc. Part 3 complements Part 2 by pulling together the information across all previously discussed fatigue mechanisms based on different types of exercise (i.e. short distance vs. middle distance sports). The book concludes in Part 4 with some thoughts on the direction of fatigue research, the interpretation of this research, and some recommendations with respect to keeping abreast the fatigue literature. Shaded “Key Point” boxes are littered throughout the test, which summarize the most important concepts of each chapter. This provides the reader with a great review and easy reference in the future. Although this book is the first of its kind, the current list price may be a barrier for some interested in the material. Irrespective of the price, I would recommend Fatigue in Sport and Exercise to all those working with an athletic population.

Reliability of Time –Trial versus Time-to- Exhaustion Cycle Tests in healthy untrained subjects

In sport science and physiology, exercise performance tests are frequently used to examine the influence of experimental interventions on endurance performance. The reliability (or reproducibility) of performance of a test refers to the consistency or reproducibility of performance when someone performs the test repeatedly. The reliability of time-to-exhaustion and time-trial performance test protocols has not been studied extensively. To date, the studies of Jeukendrup et al (cyling) and Laursen et al. (running) are the only studies that directly compared the reliability of TTE versus TT exercise tests. The reliability of TTE versus TT in healthy untrained subjects needs to be studied since athletic status, exercise intensity and duration are factors that affect the reliability of performance tests. Therefore, the purpose of this study was 1) to evaluate the reproducibility of comparable TT and TTE tests in healthy untrained male subjects; and 2) to evaluate the performance (time to completion) in the TT and TTE test with similar intensity. Methods: Eleven healthy male students volunteered to participate in this study. All participants performed a maximal incremental exercise test, followed by three time-trial (TT) tests and three time-to-exhaustion (TTE) tests. In three consecutive sessions, participants performed a cycle TT test at 65%W peak on the Excalibur Sport ergometer. The first TT was a familiarization trial. After a 5 min 100W warm-up, participants were asked to finish the TT (total amount of work; approximately 30 min cycling) in the fastest time possible. In the TT protocol, participants received no verbal encouragement and visible information about elapsed time and pedaling rate throughout the trial. During the last three sessions of the test protocol, participants performed a TTE cycle protocol, at the same individual mean power output as the previous time trials. After the standard 5 min, 100W warm-up, participants performed a TTE cycle protocol until exhaustion. In the TTE protocol, participants received no verbal encouragement and visible information about elapsed time and pedaling rate and performed work (kJ) throughout the trial. Results: The CV of the TT (3.4) was significantly lower than the CV of the TTE test (14.1) (P=0.0018). There was no difference in mean time to complete the three TT (2029 ± 150s) and the mean time-to-exhaustion of the three TTE tests (1900 ± 974s) (P=0.641). No differences were found tor the time-to-completion, power, RPM, HR, %HR max and RPE completion of the TT the TTE tests (p > 0.05). Conclusion: The main finding of this study is that the time-trial is a reliable test for performance evaluation in healthy untrained subjects. The reliability of time-to-exhaustion protocols in healthy untrained subjects was poor.

Limits to anaerobic energy and cytosolic concentration in the living cell.

For many physical systems at any given temperature, the set of all states where the system's free energy reaches its largest value can be determined from the system's constitutive equations of internal energy and entropy, once a state of that set is known. Such an approach is fraught with complications when applied to a living cell, because the cell's cytosol contains thousands of solutes, and thus thousands of state variables, which makes determination of its state impractical. We show here that, when looking for the maximum energy that the cytosol can store and release, detailed information on cytosol composition is redundant. Compatibility with cell's life requires that a single variable that represents the overall concentration of cytosol solutes must fall between defined limits, which can be determined by dehydrating and overhydrating the cell to its maximum capacity. The same limits are shown to determine, in particular, the maximum amount of free energy that a cell can supply in fast anaerobic processes, starting from any given initial state. For a typical skeletal muscle in normal physiological conditions this energy, i.e., the maximum anaerobic capacity to do work, is calculated to be about 960 J per kg of muscular mass. Such energy decreases as the overall concentration of solutes in the cytosol is increased. Similar results apply to any kind of cell. They provide an essential tool to understand and control the macroscopic response of single cells and multicellular cellular tissues alike. The applications include sport physiology, cell aging, disease produced cell damage, drug absorption capacity, to mention the most obvious ones.