Monitoring internal load parameters during simulated and official basketball matches

Moreira, A, McGuigan, MR, Arruda, AFS, Freitas, CG, and Aoki, MS. Monitoring internal load parameters during simulated and official basketball matches. J Strength Cond Res 26(3): 861-866, 2012-The purpose of this study was to compare the internal load responses (session rating of perceived exertion [RPE] and salivary cortisol) between simulated and official matches (SM and OM). Ten professional basketball players participated in 2 OMs and 2 SMs during the competition season. Subjects provided saliva samples 30 minutes before the prematch warm-up (PRE) and 10 minutes after the end of the match. Session RPE (CR-10 scale) was assessed 30 minutes after each match. The results from the 2-way analysis of variance showed significant differences for post-OM salivary cortisol as compared with pre-OM values (p < 0.05). No changes were observed for cortisol during the SM. Before the OM, a significant difference in salivary cortisol was observed as compared with pre-SM values (p < 0.05). Moreover, the OM session RPE was significantly greater than that of SM. There was a significant correlation between session RPE and cortisol changes (r = 0.75). In summary, the results of this study showed a greater magnitude of cortisol and session RPE responses after OM as compared with that after SM confirming the hypothesis that a real competition generates a greater stress response than a simulated condition does. The anticipatory effect was also observed in the OM. In addition, the results indicate that session RPE seems to be a viable tool in monitoring internal loads, and the results are useful in providing a better understanding of internal loads imposed by basketball training and competitions. The precise monitoring of these responses might help the coaches to plan appropriate loads maximizing recovery and performance.

SALIVARY CORTISOL AND IMMUNOGLOBULIN A RESPONSES TO SIMULATED AND OFFICIAL JIU-JITSU MATCHES

Moreira, A, Franchini, E, Freitas, CG, Arruda, AFS, Moura, NR, Costa, EC, and Aoki, MS. Salivary cortisol and immunoglobulin A responses to simulated and official Jiu-Jitsu matches. J Strength Cond Res 26(8): 2185-2191, 2012-The aim of this study was to compare the salivary cortisol (sC) and the salivary immunoglobulin A (sIgA) responses to simulated and official Brazilian Jiu-Jitsu (BJJ) matches. Saliva samples were collected from 9 male BJJ athletes before (pre) and after (post) 2 simulated matches (SMs) and 2 official matches (OMs) performed during 2 different competitions. Salivary cortisol and sIgA concentrations (absolute concentration of sIgA [sIgA(abs)] and the secretion rate of sIgA [sIgA(rate)]) were measured by an enzyme-linked immunosorbent assay. For sC, there was an effect of condition (SM vs. OM) (p < 0.05) and a time effect (pre and post) (p < 0.05). The sC was lower during SMs as compared with that during OMs and lower at premeasurement when compared with postmeasurement. No changes were observed for sIgA measurements. In summary, both SMs and official BJJ matches can increase sC levels. Moreover, the higher sC resting levels, observed before OMs, suggest that psychological factors associated with high physical-physiological demands from official BJJ competitions maximize stress hormone responses. In addition, the present findings suggest that the acute effect of BJJ matches on mucosal immunity is minimal, and it seems unlikely that changes in cortisol play a major role in the alterations in sIgA levels in response to BJJ matches. The findings of this study suggest that the use of sC can provide valuable information for coaches regarding athletes' responses to competition. In addition, psychological strategies should be implemented before events, to improve the manner in which BJJ athletes cope with the stress inherent to official matches.

The uncertain consequences of transferring bacterial strains between laboratories - rpoS instability as an example

Abstract Background Microbiological studies frequently involve exchanges of strains between laboratories and/or stock centers. The integrity of exchanged strains is vital for archival reasons and to ensure reproducible experimental results. For at least 50 years, one of the most common means of shipping bacteria was by inoculating bacterial samples in agar stabs. Long-term cultures in stabs exhibit genetic instabilities and one common instability is in rpoS. The sigma factor RpoS accumulates in response to several stresses and in the stationary phase. One consequence of RpoS accumulation is the competition with the vegetative sigma factor σ70. Under nutrient limiting conditions mutations in rpoS or in genes that regulate its expression tend to accumulate. Here, we investigate whether short-term storage and mailing of cultures in stabs results in genetic heterogeneity. Results We found that samples of the E. coli K-12 strain MC4100TF exchanged on three separate occasions by mail between our laboratories became heterogeneous. Reconstruction studies indicated that LB-stabs exhibited mutations previously found in GASP studies in stationary phase LB broth. At least 40% of reconstructed stocks and an equivalent proportion of actually mailed stock contained these mutations. Mutants with low RpoS levels emerged within 7 days of incubation in the stabs. Sequence analysis of ten of these segregants revealed that they harboured each of three different rpoS mutations. These mutants displayed the classical phenotypes of bacteria lacking rpoS. The genetic stability of MC4100TF was also tested in filter disks embedded in glycerol. Under these conditions, GASP mutants emerge only after a 3-week period. We also confirm that the intrinsic high RpoS level in MC4100TF is mainly due to the presence of an IS1 insertion in rssB. Conclusions Given that many E. coli strains contain high RpoS levels similar to MC4100TF, the integrity of such strains during transfers and storage is questionable. Variations in important collections may be due to storage-transfer related issues. These results raise important questions on the integrity of bacterial archives and transferred strains, explain variation like in the ECOR collection between laboratories and indicate a need for the development of better methods of strain transfer.