analysis, it was observed that, in many cases, urinary LH concentrations close to or below the threshold of 1.0 IU/L were related to low SG values (diluted samples, SG < 1.005). Based on anecdotal evidence, hyperhydration is being used by a number of athletes as a masking method, since urine dilution is
Ioanna Athanasiadou, Sven Christian Voss, Wesal El Saftawy, Hind Al-Jaber, Najib Dbes, Sameera Al-Yazedi, Waseem Samsam, Vidya Mohamed-Ali, Mohammed Alsayrafi, Georgia Valsami and Costas Georgakopoulos
Blake D. McLean, Cloe Cummins, Greta Conlan, Grant Duthie and Aaron J. Coutts
% during straight line running), which could mask any small load increases in the anteroposterior and mediolateral axes that may occur during tackling drills. It has previously been shown that 3D accelerometer loads are strongly influenced by total distance traveled during locomotor activities (due to the
Judy L. Van Raalte, Lorraine Wilson, Allen Cornelius and Britton W. Brewer
sport of SCUBA diving are particularly interesting, because failure to execute SCUBA diving skills correctly can result in injury or even death. Mask clearing is one of many fundamental SCUBA diving skills. SCUBA divers must clear their masks when water leaks into the mask, which can happen under
Geoff Minett, Rob Duffield and Stephen P. Bird
To investigate the effects of an acute multinutrient supplement on game-based running performance, peak power output, anaerobic by-products, hormonal profiles, markers of muscle damage, and perceived muscular soreness before, immediately after, and 24 h following competitive rugby union games.
Twelve male rugby union players ingested either a comprehensive multinutrient supplement (SUPP), [RE-ACTIVATE:01], or a placebo (PL) for 5 d. Participants then performed a competitive rugby union game (with global positioning system tracking), with associated blood draws and vertical jump assessments pre, immediately post and 24 h following competition.
SUPP ingestion resulted in moderate to large effects for augmented 1st half very high intensity running (VHIR) mean speed (5.9 ± 0.4 vs 4.8 ± 2.3 m·min−1; d = 0.93). Further, moderate increases in 2nd half VHIR distance (137 ± 119 vs 83 ± 89 m; d = 0.73) and VHIR mean speed (5.9 ± 0.6 v 5.3 ± 1.7 m·min−1; d = 0.56) in SUPP condition were also apparent. Postgame aspartate aminotransferase (AST; 44.1 ± 11.8 vs 37.0 ± 3.2 UL; d = 1.16) and creatine kinase (CK; 882 ± 472 vs. 645 ± 123 UL; d = 0.97) measures demonstrated increased values in the SUPP condition, while AST and CK values correlated with 2nd half VHIR distance (r = −0.71 and r = −0.76 respectively). Elevated C-reactive protein (CRP) was observed postgame in both conditions; however, it was significantly blunted with SUPP (P = .05).
These findings suggest SUPP may assist in the maintenance of VHIR during rugby union games, possibly via the buffering qualities of SUPP ingredients. However, correlations between increased work completed at very high intensities and muscular degradation in SUPP conditions, may mask any anticatabolic properties of the supplement.
David Morawetz, Tobias Dünnwald, Martin Faulhaber, Hannes Gatterer and Wolfgang Schobersberger
) preconditioning phase. In the first trial, pure oxygen was administered to group I1 (FiO 2 = 1.0), whereas group I0 breathed chamber air equal to 3500 m (nonhyperoxic). Both groups breathed through a mask. During the final minute of the preconditioning phase, capillary blood (t2) was collected and analyzed
David Morawetz, Tobias Dünnwald, Martin Faulhaber, Hannes Gatterer, Lukas Höllrigl, Christian Raschner and Wolfgang Schobersberger
administered pure oxygen to I1 (FiO 2 = 1.0), whereas I0 breathed chamber air (equal to 3500 m). All participants breathed through a mask. Capillary blood (t2) was collected and analyzed again during the last minute of the preconditioning phase. Immediately after the 5-minute preconditioning phase, subjects
R. Pla, Y. Le Meur, A. Aubry, J.F. Toussaint and P. Hellard
immediately using backward extrapolation and a K4b2 gas analyzer (Cosmed, Rome, Italy) connected to a face mask (Hans Rudolph, Inc, Shawnee, KS). As soon as the swimmer’s head was out of the water, the mask was put on the swimmer for 30 seconds. The first 20 seconds were used for the analysis to determine V
Sjors Groot, Lars H.J. van de Westelaken, Dionne A. Noordhof, Koen Levels and Jos J. de Koning
checked during every calibration and accepted if between 50 and 200 ms. Dead space of the mask depended on the size of the mask (small: 50 mL; medium: 60 mL). The volume transducer was calibrated using a 3-L volume syringe (COSMED srl). Heart rate was measured during the test with a heart rate monitor
Louise M. Burke and Peter Peeling
specific scenarios. Many available studies suffer from limitations in methodology which may mask a true interpretation of the results. Research that is poorly conducted or interpreted may result in type 1 (incorrect attribution of a performance change) or type II (failure to detect a true performance
Dennis van Erck, Eric J. Wenker, Koen Levels, Carl Foster, Jos J. de Koning and Dionne A. Noordhof
test, corresponding to the manufacturer’s instructions. The mask that was used to collect respiratory data was also used to supply air to the participants. The mask was connected to a bag of air (hypoxic or normoxic), which contained air produced by the b-CAT High-Altitude (b-CAT BV, Tiel, the