Chronic glutamine supplementation increases nasal but not salivary IgA during 9 days of interval training.

Oral glutamine supplementation during and after exercise abolishes exercise-induced decreases in plasma glutamine concentration but does not affect secretory IgA (sIgA) salivary output. Whether chronic glutamine supplementation during high-intensity interval training influences salivary and nasal sIgA concentration is unknown. The purpose of this study was examine the effects of chronic glutamine supplementation on sIgA during intense running training. Runners (n = 13, body mass 69.9 +/- 2.8 kg, peak whole body oxygen uptake 55.5 +/- 2 ml.kg(-1).min(-1), age 29.1 +/- 2.8 yr) participated in twice-daily interval training for 9-9.5 days, followed by recovery (5-7 days). Oral glutamine supplement (0.1 g/kg) or placebo was given four times daily for the first 14 days. After an overnight fast, venous blood, nasal washes, and stimulated saliva were collected at baseline (T1), midtraining (T2), posttraining (T3), and after recovery (T4). Mood states were assessed by using Profile of Mood States (POMS) inventories. We found that glutamine concentration in resting subjects decreased from T1 to T4 (P < 0.05) and was not altered by supplementation. Salivary IgA concentration and output were unchanged by training or supplementation. Mean nasal IgA across the study period was greater in runners receiving glutamine (264.7 +/- 35.0 microg/mg protein) vs. placebo (172.4 +/- 33.7 microg/mg protein; P < 0.05). POMS analyses indicated that vigor was lower at T3 vs. T1 (P < 0.05) and fatigue was higher at T2 vs. T1 and T4 (P < 0.05). We conclude that chronic glutamine supplementation during interval training results in higher nasal IgA than placebo but does not affect salivary IgA concentration or output.     

SALIVARY IL-21 AND IGA RESPONSES TO A COMPETITIVE MATCH IN ELITE BASKETBALL PLAYERS

Athletes engaged in strenuous training might experience transient immune suppression that could lead to greater incidence of upper respiratory tract infections (URTI). Since interleukin 21 (IL-21) stimulates immunoglobulin A (IgA) secreting cells and a low level of this immunoglobulin is associated with increased incidence of URTI, the aim of the present study was to investigate the effect of a basketball match on salivary cortisol (sC), salivary IL-21 (sIL-21) and salivary IgA (sIgA) levels. Twenty male basketball players participated in an official game in two teams (10 players in each team). The saliva samples were collected before the warm-up and approximately 10-15 min after the end of the match and were analysed by ELISA methods. sC concentration increased significantly after the match while sIL-21 level was reduced (p < 0.05). In opposition to the study''s hypothesis, sIgA level did not change in response to the match. The present findings suggest that a basketball match is sufficiently stressful to elevate sC concentration and attenuates the sIL-21 output without compromising the sIgA level. It is reasonable to speculate that the stability of sIgA acute responses to the match, despite the decrement in sIL-21, indicates that other mechanisms rather than IL-21 stimulating B cell proliferation/differentiation might modulate IgA concentration and secretion rate.     

Effect of competition on salivary cortisol, immunoglobulin A, and upper respiratory tract infections in elite young soccer players

The present study examined the effect of a 20-day period of competition on salivary cortisol, mucosal immunity, and upper respiratory tract infections (URTI) in young male soccer players (n = 14). The players were monitored during the main under-19 Brazilian soccer championship, in which 7 matches were played in 20 days. Saliva samples were collected in the morning of each match and analyzed for cortisol and immunoglobulin A (IgA). Signs and symptoms of URTI were assessed across the study and a rating of perceived exertion (RPE) was obtained for each match. Compared with match 1, a significant increase in player RPE was observed in matches 4-7 (p < 0.05). Significant (p < 0.05) increases in the reporting of URTI occurred between matches 2 and 3, and 6 and 7, and this was accompanied by significant decreases in salivary IgA levels. Significant (p < 0.05) correlations were also seen between the individual reports of URTI and the decrease in IgA levels in match 2 (r = -0.60) and match 6 (r = -0.65). These results suggest that decrements in mucosal immunity, as measured by salivary IgA concentrations, may lead to a greater incidence of URTI in elite young soccer players. It may be speculated that the physiological and psychological stressors imposed by training and competition in a short timeframe are major contributing factors to these responses. Thus, the monitoring of salivary IgA could provide a useful and noninvasive approach for predicting URTI occurrences in young athletes during short-term competitions, especially if frequent sampling and rapid measurements are made.     

Salivary hormonal responses and performance changes during 15 weeks of mixed aerobic and weight training in elite junior wrestlers

ABSTRACT: Passelergue, PA and Lac, G. Salivary hormonal responses and performance changes during 15 weeks of mixed aerobic and weight training in elite junior wrestlers. J Strength Cond Res 26(11): 3049-3058, 2012-To prepare efficiently for competition, wrestlers usually train physically for a period of approximately 12-20 weeks. Numerous physical qualities must be developed during this period of preparation: aerobic fitness, maximal strength, muscular endurance, power, and speed. However, numerous studies have concluded that it is difficult to concurrently develop strength and aerobic fitness for several reasons, in particular antagonistic endocrine variations. The study involved 15 elite junior wrestlers who trained at a sports training school for 15 weeks. To investigate the effects of long-term training and to assess the relationships between hormonal concentrations (salivary testosterone [T] and cortisol [C]) and performance changes during simultaneous strength and aerobic fitness training, 6 saliva samples and 3 physical tests and 2 measures of body composition were made during the training period. Wrestlers had a significant increase (+1.5 kg) in body weight without changes in percentage body fat. Apart from the 20-m maximal shuttle speed, all performances increased significantly during the 15 weeks of training: maximum mechanical power output (Pmax: +12.8%), mean power during 30 seconds (Pmean: +10.8%), bench press (+5.7%), squat (+23.1%), power clean (+6.1%), time to 3,000- and 30-m sprints (-3.6, -1.3% respectively). During the period that the C increased, there was no significant variation for the T. The T/C ratio followed a variation pattern contrary to that of the C. We found strong correlations between salivary T, C, and T/C and the variation in explosive strength. Our results suggest that data about subjects' salivary C, T, and T/C may be employed to optimize the training process for sports people who need to develop strength and aerobic fitness simultaneously.     

Genetic consequences of interglacial isolation in a steppe bird

In response to climate changes that have occurred during Pleistocene glacial cycles, taxa associated to steppe vegetation might have followed a pattern of historical evolution in which isolation and fragmentation of populations occurred during the short interglacials and expansion events occurred during the long glacial periods, in contrast to the pattern described for temperate species. Here, we use molecular genetic data to evaluate this idea in a steppe bird with Palaearctic distribution, the little bustard (Tetrax tetrax). Overall, extremely low genetic diversity and differentiation was observed among eight little bustard populations distributed in Spain and France. Mismatch distribution analyses showed that most little bustard populations expanded during cooling periods previous to, and just after, the last interglacial period (127,000-111,000 years before present), when steppe habitats were widespread across Europe. Coalescent-based methods suggested that glacial expansions have resulted in substantial admixture in Western Europe due to the existence of different interglacial refugia. Our results are consistent with a model of evolution and genetic consequences of Pleistocene cycles with low between-population genetic differentiation as a result of short-term isolation periods during interglacials and long-term exchange during glacial periods.     

Salivary hormone and immune responses to three resistance exercise schemes in elite female athletes

This study examined the salivary hormone and immune responses of elite female athletes to 3 different resistance exercise schemes. Fourteen female basketball players each performed an endurance scheme (ES-4 sets of 12 reps, 60% of 1 repetition maximum (1RM) load, 1-minute rest periods), a strength-hypertrophy scheme (SHS-1 set of 5RM, 1 set of 4RM, 1 set of 3RM, 1 set of 2RM, and 1set of 1RM with 3-minute rest periods, followed by 3 sets of 10RM with 2-minute rest periods) and a power scheme (PS-3 sets of 10 reps, 50% 1RM load, 3-minute rest periods) using the same exercises (bench press, squat, and biceps curl). Saliva samples were collected at 07:30 hours, pre-exercise (Pre) at 09:30 hours, postexercise (Post), and at 17:30 hours. Matching samples were also taken on a nonexercising control day. The samples were analyzed for testosterone, cortisol (C), and immunoglobulin A concentrations. The total volume of load lifted differed among the 3 schemes (SHS > ES > PS, p < 0.05). Postexercise C concentrations increased after all schemes, compared to control values (p < 0.05). In the SHS, the postexercise C response was also greater than pre-exercise data (p < 0.05). The current findings confirm that high-volume resistance exercise schemes can stimulate greater C secretion because of higher metabolic demand. In terms of practical applications, acute changes in C may be used to evaluate the metabolic demands of different resistance exercise schemes, or as a tool for monitoring training strain.     

Widening the window of persistence in seasonal pathogen-host systems

Local instability of exploiter-victim systems is well-known in both theory and in nature. Victims can be too sparse to support exploiter reproduction (under-exploitation) or they can be too readily driven to extinction (over-exploitation). Exploiters of seasonal resources face the additional challenge of surviving periods when victims are rare or unavailable. We formulate a fully stochastic model of highly seasonal pathogen-host dynamics and explore the interactions between an entomopathogenic nematode and its lepidopteran host. Our model suggests that if nematode populations experience the high rates of mortality predicted by short-term laboratory experiments, the paired threats of under- and over-exploitation should preclude the long-term persistence of this exploiter-victim system. We measured nematode mortality rates in the field and found that long-term mortality is lower than that predicted by short-term experiments. Incorporation of this new data into our model produces long-term persistence of local nematode populations across a range of initial nematode densities.     

Testosterone, cortisol, and mood in a sports team competition

In humans, hormonal responses to winning/losing and their relationships to mood and status change have mostly been examined in individual athletic competitions. In this study, the salivary testosterone (T) and cortisol (C) and mood responses to a real match between two professional basketball teams were investigated. Data about individuals' contributions to outcome, performance appraisal, and attribution of outcome to internal/external factors were also collected. Results did not show statistically significant different T and C responses depending on the outcome. Negative mood was significantly enhanced, especially in the losers, while winners showed a better appraisal of team performance and a more internal attribution. T response did not show a significant relationship with mood changes, but it correlated positively with the "score/time playing" ratio, an indicator of individual participation in the outcome. Furthermore, T response correlated negatively with external attribution in winners and positively in losers. These results indicate that in a real, highly competitive situation, T changes are not directly a response to the outcome, but rather to the contribution the individual makes to it and to the causes he attributes.     

Combining small-sided soccer games and running-based methods: A systematic review

Small-sided games (SSGs) are often used in soccer to produce acute physiological and physical responses, while a tactical/technical stimulus is also employed. However, due to some limitations of SSGs, researchers have been testing this method combined with running-based training methods. This systematic review was conducted to assess the effects of combined SSG and running-based methods on soccer players’ acute responses and adaptations after training interventions. A systematic review of Web of Science, PubMed, Cochrane Library, Scopus, and SPORTDiscus databases was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The database search initially identified 782 titles. From those, five articles were deemed eligible for the systematic review. The five included studies presented data from training load, reporting inconsistent greater values in combined SSG and running-based methods when compared to SSG-only formats. Considering the adaptations, studies comparing combined SSG and running-based methods with SSG-only methods revealed inconsistent differences in terms of the effects on aerobic performance and sprinting. Combining SSG and running-based methods can increase the acute mechanical load and high-intense running stimuli in players when compared to interventions that use only SSGs. However, the adaptations promoted by both methods are similar, and the differences are unclear. The order of combination (SSG and running-based method) does not seem to impact players’ adaptations; however, the frequency of sessions did have a meaningful impact.     

Reduction of saliva immunoglobulin levels by swim training

Saliva immunoglobulin A (IgA) and cortisol levels were measured in 21 male members of a major midwestern swim team. Saliva samples were collected before and after training sessions four times during the fall season; the training intensity was light, moderate, heavy and during the taper period before a major competitive meet. Saliva IgA levels were decreased after each training session, reaching statistical significance with the moderate training intensity. Over the 3-month training period the pre-session and post-session IgA levels both decreased significantly during the heavy and taper training intensities later in the fall season. Cortisol levels were significantly elevated only after the heavy-intensity training session. The Profile of Mood States (POMS) was used to assess the swimmers' overall mood on each test day. No significant correlations were found between the global POMS score and IgA or cortisol. Also, cortisol and IgA were not significantly correlated except after the light training session. Results from this study indicate that acute bouts of exercise can reduce salivary IgA levels and that chronic exercise of high intensity can reduce the resting levels of IgA. These changes may render the athletes more vulnerable to respiratory infections after exercise and even at rest during the later stages of the competitive season.     

Salivary IgA subclasses and infection risk in elite swimmers.

The concentrations of total IgA, IgA1 and IgA2 were measured in saliva collected from 25 elite swimmers in the early and late phases of a 7 month training season and compared with the number of respiratory infections during the season. The IgA1 concentrations in the early phase of the training season were significantly associated (P = 0.01) with the number of respiratory infection episodes during the training season. The lower the concentration of IgA1, the greater the number of infection episodes. Swimmers with four or more infections during the training season had significantly lower salivary IgA1 concentrations than those with less than four infection episodes (P = 0.01). The proportion of IgA1 in the saliva of the elite swimmers (80%) was higher than for normal non-exercising adults (60%). A small proportion of athletes had salivary IgA2 concentrations below the detection limit of the assay and the mean concentration of IgA2 was significantly lower than the concentrations for a normal adult population (P = 0.01). This study suggests that measurement of IgA subclasses, in particular IgA1, at the commencement of a training season may predict infection risk in elite swimmers.     

Temporal variation in the genetic structure of host-associated populations of the small ermine moth Yponomeuta padellus (Lepidoptera, Yponomeutidae)

Temporal changes in allele frequencies were studied in host-associated populations of the small ermine moth Yponomeuta padellus. At one site, populations from three host plants (Sorbus aucuparia, Amelanchier larnarckii , and Crataegus spp.) were sampled annually during a four-year-period and analysed with 20 polymorphic allozyme markers. At two other sites, allele frequencies at 5- 6 enzyme loci of Y. padellus populations from two different host plants were also tested for consistency over a 13-year-pcriod. Significant allele frequency changes occurred in the short-term analysis, whereas allele frequencies remained relatively stable through time in the long-term analyses. Furthermore, allele frequencies of Y. padellus populations from Crataegus spp. were relatively stable compared to the other host populations. The role of the agents responsible for the observed patterns is discussed.     

Effects of the number of players and game type constraints on heart rate, rating of perceived exertion, and technical actions of small-sided soccer games

The purpose of this study was to identify the variation of heart rate (HR), rating of perceived exertion (RPE), and technical actions between 2 soccer small-sided games (SSGs; 3 × 3 and 4 × 4) in 3 game type constraints (when playing only offense [OFF], playing only defense [DEF], and both situations [GAME]). Sixteen high-level young male players were analyzed (age 15.75 ± 0.45 years; height 172.4 ± 4.83 cm; body mass 64.5 ± 6.44 kg; HRmax199.1 ± 9.08 b·min(-1); and 8.06 ± 1.98 years of soccer practice). All tasks were performed in 4 periods of 4 minutes interspersed with 2 minutes of active recovery. The HR was measured continuously and then analyzed by the time spent into 4 training zones according to individual %HRmax (zone 1 <75%; zone 2 75-84.9%; zone 3 85-89.9%; and zone 4 ≥90%). Results identified that players were most frequently in zones 2 and 3. The 3 × 3 SSGs elicited higher HR and RPE and the most intense situation was GAME. Despite the known higher frequencies from technical actions in SSGs with fewer players, player effectiveness in 3 × 3 and 4 × 4 was identical. The use of GAME, OFF, and DEF game type constraints should be carefully planned. Using the 3 × 3 format seems more adequate when aiming for aerobic performance optimal effects; however, DEF situations should only be used to promote aerobic recovery effects. The inclusion of an additional player in SSGs had different interactions in game type constraints, and only GAME presented adequate intensity.     

Small-Sided Games Versus Interval Training in Amateur Soccer Players: Effects on the Aerobic Capacity and the Ability to Perform Intermittent Exercises With Changes of Direction

ABSTRACT: Dellal, A, Varliette, C, Owen, A, Chirico, EN, and Pialoux, V. Small-sided games versus interval training in amateur soccer players: Effects on the aerobic capacity and the ability to perform intermittent exercises with changes of direction. J Strength Cond Res 26(10): 2712-2720, 2012-The purpose of this study was to compare the effects of small-sided games (SSGs) in soccer versus high-intensity intermittent training (HIT) on a continuous aerobic test (Vameval) and the performance in an intermittent test with changes of direction (CODs; 30-15 intermittent fitness test [30-15IFT]). Twenty-two amateur soccer players (mean age ± SD: 26.3 ± 4.7 years) were assigned to 3 different groups for 6 weeks: SSG group (n = 8), HIT group (n = 8), and control group (CG; n = 6). In addition to the usual technical and tactical sessions and competitive games, the SSG group performed 9 sessions of 2 versus 2 and 1 versus 1 SSGs, whereas the HIT group performed 9 sessions of intermittent runs in the form of 30 seconds of effort interspersed with 30 seconds of passive recovery (30s-30s), 15s-15s, and 10s-10s. The HIT and SSG groups showed performance improvements in the Vameval test (5.1 and 6.6%, respectively) and the 30-15IFT intermittent test with CODs (5.1 and 5.8%, respectively), whereas there was no change in the performance of the CG. Players from HIT and SSG groups showed similar increase in their performance in the 30-15IFT and the Vameval tests during the 6-week training period, especially with an increase significantly different to that in a traditional training as in the CG (p < 0.05). This investigation demonstrates that both SSG and HIT interventions are equally effective in developing the aerobic capacity and the ability to perform intermittent exercises with CODs in male amateur soccer players. Furthermore, these 2 methods of training applied during the 6 weeks induce similar effect on the recovery capacity and on the ability to repeat directional changes of 180°. Coaches will now be able to choose between these two methods according to the objective of the training and to optimize the training.     

Special feature for the Olympics: effects of exercise on the immune system: exercise effects on mucosal immunity

The present review examines the effects of exercise on mucosal immunity in recreational and elite athletes and the role of mucosal immunity in respiratory illness. Habitual exercise at an intense level can cause suppression of mucosal immune parameters, while moderate exercise may have positive effects. Saliva is the most commonly used secretion for measurement of secretory antibodies in the assessment of mucosal immune status. Salivary IgA and IgM concentrations decline immediately after a bout of intense exercise, but usually recover within 24 h. Training at an intense level over many years can result in a chronic suppression of salivary immunoglobulin levels. The degree of immune suppression and the recovery rates after exercise are associated with the intensity of exercise and the duration or volume of the training. Low levels of salivary IgM and IgA, particularly the IgA1 subclass, are associated with an increased risk of respiratory illness in athletes. Monitoring mucosal immune parameters during critical periods of training provides an assessment of the upper respiratory tract illness risk status of an individual athlete. The mechanisms underlying the mucosal immune suppression are unknown.     

Crossing barriers in an extremely fragmented system: two case studies in the afro-alpine sky island flora

The flora on the afro-alpine sky islands is renowned for extreme fragmentation, representing a unique natural experiment in biogeography. Here we address the roles of isolation and gene flow, in particular across the narrow Rift Valley (the RV barrier) that cuts through the Ethiopian Highlands (EH), and across the vast low-lying landscape that separates EH from the East African mountains (the EH–EA barrier). We inferred the history of two species with different dispersal mechanisms, but with similar geographic ranges and habitats based on Amplified fragment length polymorphisms (AFLPs). Contrary to our predictions, we found that the populations from opposite sides of the RV barrier were less similar than those from opposite sides of the EH–EA barrier, and that only the supposedly short distance-dispersed species (Trifolium cryptopodium) showed a strong signal of secondary gene flow across the RV barrier. In the wind-dispersed Carduus schimperi, we rather found an evidence for the gene flow between differentiated populations inhabiting different EA mountains. Both species harbored little genetic diversity but considerable genetic rarity in several individual mountains, suggesting long-term isolation and bottlenecks during climatically unfavorable periods. Our genetic data corroborate a division of C. schimperi into three subspecies, but with new delimitation of their ranges, and of T. cryptopodium into two intraspecific taxa. Our findings support the idea that stochasticity may play a major role in shaping extremely fragmented ecosystems such as the afro-alpine. After initial colonization of different mountains, periods of isolation may alternate with unpredictable episodes of intermountain gene flow.     

Under pressure: Short- and long-term response to predation varies in two populations of a live-bearing fish

The non-lethal effects of predation can significantly influence animal behavior and population composition. Research has often centered around prey response to predator exposure in the short term, but fewer studies have highlighted the effects of long-term predator exposures. In addition, studies of responses to predation risk are not always calibrated against the ecological history of predation risk in specific populations. We address these gaps by examining the effects of both long- and short-term predator exposure on the behavior of individuals from populations that have different ecological histories of predation risk. We exposed individuals from high-predation and low-predation populations of the live-bearing freshwater poeciliid, Heterandria formosa, to predators to assess changes in male reproductive behavior toward females. We also assessed longer-term reproductive responses by exposing male and female H. formosa to predators at a random time of day, every day, for 30 days. In the presence of a predator, in the short term, males changed the frequency of their behaviors and females varied in their concentration of cortisol, demonstrating immediate responses to the perceived risk. The magnitude of these changes was larger in the population without a long history of predator exposure. However, we found that males and females did not change their reproductive output when exposed to predators over longer periods of time, suggesting that individuals acclimatize to the level of predation risk they experience. These results also suggest that short-term variation in behavior or stress hormone responses should not be used as proxies for long-term responses or fitness effects. Future work should assess both short-term behavior and long-term responses while simultaneously considering the ecological history of populations.     

Body temperature in captive long-beaked echidnas (Zaglossus bartoni)

The routine occurrence of both short-term (daily) and long-term torpor (hibernation) in short-beaked echidnas, but not platypus, raises questions about the third monotreme genus, New Guinea's Zaglossus. We measured body temperatures (T(b)) with implanted data loggers over three and a half years in two captive Zaglossus bartoni at Taronga Zoo, Sydney. The modal T(b) of both long-beaks was 31 degrees C, similar to non-hibernating short-beaked echidnas, Tachyglossus aculeatus, in the wild (30-32 degrees C) and to platypus (32 degrees C), suggesting that this is characteristic of normothermic monotremes. T(b) cycled daily, usually over 2-4 degrees C. There were some departures from this pattern to suggest periods of inactivity but nothing to indicate the occurrence of long-term torpor. In contrast, two short-beaked echidnas monitored concurrently in the same pen showed extended periods of low T(b) in the cooler months (hibernation) and short periods of torpor at any time of the year, as they do in the wild. Whether torpor or hibernation occurs in Zaglossus in the wild or in juveniles remains unknown. However, given that the environment in this study was conducive to hibernation in short-beaks, which do not easily enter torpor in captivity, and their large size, we think that torpor in wild adult Zaglossus is unlikely.     

Differential recognition of oral indigenous bacteria by salivary immunoglobulins A and G

Assuming that salivary immunity to indigenous microorganisms could develop, we assessed antibacterial reactivities of natural salivary antibodies in specific pathogen-free inbred mice. An ELISA was set up, using whole bacterial cells, to map reactivities of salivary IgA and IgG which accounted respectively for 91% and 8.7% of salivary Ig's in the BALB/c mouse. Representative strains of seven species from three genera (Lactobacilli, Staphylococci, and Streptococci), including major and minor components of the murine oral flora (38, 43, and 8%, respectively), were used to determine the presence and level of specific antibodies in individual saliva. It was verified that naturally occurring IgA antibodies can display diverse antibacterial reactivities. A characteristic profile emerged for salivary IgA where antibodies to Streptococcus faecalis predominate. Natural salivary IgG antibodies did not show the same reactivity pattern as IgA, anti-Lactobacilli and anti-Staphylococci reactivities being much less frequent in the salivary IgG repertoire. However, antibodies to S. faecalis occurred at the same high frequency for both isotypes (62-70% of the samples). Besides being species-specific, antibacterial reactivities were also found to be strain-specific. Broad variations in antibacterial titers were detected among individual mice under standardized experimental conditions. Present data thus suggest that the dynamics of salivary antibody production in the mouse reflect a differential natural sensitization of the secretory (IgA) versus the systemic (IgG) immune systems by distinct populations of indigenous bacteria.