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The purpose of this study is to evaluate the influence of competition level on running patterns for five playing position in the most successful 2014–2015 European rugby union team. Seventeen French rugby union championship and seven European rugby Champions Cup games were analysed. Global positioning system (sampling: 10 Hz) were used to determine high-speed movements, high-intensity accelerations, repeated high-intensity efforts and high-intensity micro-movements characteristics for five positional groups. During European Champions Cup games, front row forwards performed a higher number of repeated high-intensity efforts compared to National championship games (5.8±1.6 vs. 3.6±2.3; +61.1%), and back row forwards travelled greater distance both at high-speed movements (3.4±1.8 vs. 2.4±0.9 m·min-1 ; +41.7%) and after high-intensity accelerations (78.2±14.0 vs. 68.1 ±13.4 m; +14.8%). In backs, scrum halves carried out more high-intensity accelerations (24.7±3.1 vs. 14.8±5.0; +66.3%) whereas outside backs completed a higher number of high-speed movements (62.7±25.4 vs. 48.3±17.0; +29.8%) and repeated high-intensity efforts (13.5±4.6 vs. 9.7±4.9; +39.2%). These results highlighted that the competition level affected the high-intensity activity differently among the five playing positions. Consequently, training programs in elite rugby should be tailored taking into account both the level of competition and the high-intensity running pattern of each playing position. [ABSTRACT FROM AUTHOR]

Context: A passive knee-extension test has been shown to be a reliable method of assessing hamstring tightness, but this method does not take into account the potential effect of gravity on the tested leg. Objective: To compare an original passive knee-extension test with 2 adapted methods including gravity's effect on the lower leg. Design: Repeated measures. Setting: Laboratory. Participants: 20 young track and field athletes (16.6 ± 1.6 y, 177.6 ± 9.2 cm, 75.9 ± 24.8 kg). Intervention: Each subject was tested in a randomized order with 3 different methods: In the original one (M1), passive knee angle was measured with a standard force of 68.7 N (7 kg) applied proximal to the lateral malleolus. The second (M2) and third (M3) methods took into account the relative lower-leg weight (measured respectively by handheld dynamometer and anthropometrical table) to individualize the force applied to assess passive knee angle. Main Outcome Measures: Passive knee angles measured with video-analysis software. Results: No difference in mean individualized applied force was found between M2 and M3, so the authors assessed passive knee angle only with M2. The mean knee angle was different between M1 and M2 (68.8 ± 12.4 vs 73.1 ± 10.6, P < .001). Knee angles in M1 and M2 were correlated (r = .93, P < .001). Conclusions: Differences in knee angle were found between the original passive knee-extension test and a method with gravity correction. M2 is an improved version of the original method (M1) since it minimizes the effect of gravity. Therefore, we recommend using it rather than M1. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to compare VO2 kinetics during constant power cycle exercise measured using a conventional facemask (CM) or a respiratory snorkel (RS) designed for breath-by-breath analysis in swimming. Methods: VO2 kinetics parameters--obtained using CM or RS, in randomized counterbalanced order--were compared in 10 trained triathletes performing two submaximal heavy-intensity cycling square-wave transitions. These VO2 kinetics parameters (ie, time delay: td1, td2; time constant: ô1, ô2; amplitude: A1, A2, for the primary phase and slow component, respectively) were modeled using a double exponential function. In the case of the RS data, this model incorporated an individually determined snorkel delay (ISD). Results: Only td1 (8.9 ± 3.0 vs 13.8 ± 1.8 s, P < .01) differed between CM and RS, whereas all other parameters were not different (ô1 = 24.7 ± 7.6 vs 21.1 ± 6.3 s; A1 = 39.4 ± 5.3 vs 36.8 ± 5.1 mL.min.1.kg.1; td2 = 107.5 ± 87.4 vs 183.5 ± 75.9 s; A2. (relevant slow component amplitude) = 2.6 ± 2.4 vs 3.1 ± 2.6 mL.min.1.kg.1 for CM and RS, respectively). Conclusions: Although there can be a small mixture of breaths allowed by the volume of the snorkel in the transition to exercise, this does not appear to significantly influence the results. Therefore, given the use of an ISD, the RS is a valid instrument for the determination of VO2 kinetics within submaximal exercise. [ABSTRACT FROM AUTHOR]

The relationships between sport sciences and sports are complex and changeable, and it is not clear how they reciprocally influence each other. By looking at the relationship between sport sciences and the "new" (∼30-year-old) sport of triathlon, together with changes in scientific fields or topics that have occurred between 1984 and 2006 (278 publications), one observes that the change in the sport itself (eg, distance of the events, wetsuit, and drafting) can influence the specific focus of investigation. The sport-scientific fraternity has successfully used triathlon as a model of prolonged strenuous competition to investigate acute physiological adaptations and trauma, as support for better understanding cross-training effects, and, more recently, as a competitive sport with specific demands and physiological features. This commentary discusses the evolution of the scientific study of triathlon and how the development of the sport has affected the nature of scientific investigation directly related to triathlon and endurance sport in general. [ABSTRACT FROM AUTHOR]

We aimed to analyse the relationship between training load/intensity and different heart rate variability (HRV) fatigue patterns in 57 elite Nordic-skiers. 1063 HRV tests were performed during 5 years. R-R intervals were recorded in resting supine (SU) and standing (ST) positions. Heart rate, low (LF), high (HF) frequency powers of HRV were determined. Training volume, training load (TL, a.u.) according to ventilatory threshold 1 (VT1) and VT2 were measured in zones I ≤ VT1; VT1 < II ≤ VT2; III > VT2, IV for strength. TL was performed at 81.6 ± 3.5 % in zone I, 0.9 ± 0.9 % in zone II, 5.0 ± 3.6 % in zone III, 11.6 ± 6.3 % in zone IV. 172 HRV tests matched a fatigue state and four HRV fatigue patterns (F) were statistically characterized as F(HF-LF-) SU&lowbar;ST for 121 tests, F(LF + SULF-ST) for 18 tests, F(HF-SUHF+ ST) for 26 tests and F(HF + SU) for 7 tests. The occurrence of fatigue states increased substantially with the part of altitude training time (r2 = 0.52, p < 0.001). This study evidenced that there is no causal relationship between training load/intensity and HRV fatigue patterns. Four fatigue-shifted HRV patterns were sorted. Altitude training periods appeared critical as they are likely to increase the overreaching risks. [ABSTRACT FROM AUTHOR]

We compare the macro-kinematics of six elite female cross-country skiers competing in 1.1-m Sprint and 10.5-km Distance classical technique events on consecutive days under similar weather and track conditions. The relative use of double pole (DP), kick-double pole (KDP), diagonal stride (DS), tucking (Tuck) and turning (Turn) sub-techniques, plus each technique's respective velocities, cycle lengths and cycle rates were monitored using a single micro-sensor unit worn by each skier during the Sprint qualification, semi-final and finals, and multiple laps of the Distance race. Over a 1.0-km section of track common to both Sprint and Distance events, the mean race velocity, cyclical sub-technique velocities, and cycle rates were higher during the Sprint race, while Tuck and Turn velocities were similar. Velocities with KDP and DS on the common terrain were higher in the Sprint (KDP +12%, DS +23%) due to faster cycle rates (KDP +8%, DS +11%) and longer cycle lengths (KDP +5%, DS +10%), while the DP velocity was higher (+8%) with faster cycle rate (+16%) despite a shorter cycle length (-9%). During the Sprint the percentage of total distance covered using DP was greater (+15%), with less use of Tuck (-19%). Across all events and rounds, DP was the most used sub-technique in terms of distance, followed by Tuck, DS, Turn and KDP. KDP was employed relatively little, and during the Sprint by only half the participants. Tuck was the fastest sub-technique followed by Turn, DP, KDP, and DS. These findings reveal differences in the macro-kinematic characteristics and strategies utilized during Sprint and Distance events, confirm the use of higher cycle rates in the Sprint, and increase our understanding of the performance demands of cross-country skiing competition. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the differences in maximal oxygen uptake (...O2max) and submaximal thresholds between a standard graded exercise test (GXT) and a perceptually regulated graded exercise test (PRGXT) in trained runners. Eleven well-trained middle- to long-distance runners performed both tests in a randomized order. PRGXT used incremental "clamps" of rating of perceived exertion (RPE) over 10 X 1-min stages on an automated treadmill equipped with a sonar sensor allowing them to change their running speed instantly and in a natural way. GXT used fixed 1 km.h-1 increment every minute. Ventilatory threshold (VT) and respiratory compensation point (RCP) were determined using ventilatory equivalents. No differences were found in ...O2max (68.0 (5.3) vs. 69.5 (5.9) ml ⋅ min-1 ⋅ kg -1, p = 0.243), minute ventilation (...E) (159.4 (35.0) vs. 162.4 (33.7) l ⋅ min-1, p = 0.175), heart rate (HR) (188.4 (6.9) vs. 190.7 (5.2) bpm, p = 0.254) and speed (21.0 (1.7) vs. 21.1 (2.3) km ⋅ h-1, p = 0.761) between GXT and PRGXT. At VT, there were no significant differences between GXT and PRGXT for any outcome variables. For 8 of 11 subjects, it was not possible to determine RCP from ventilatory equivalent in PRGXT. GXT appears more relevant for a comprehensive gas analysis in trained runners. [ABSTRACT FROM AUTHOR]

Purpose: To analyze if live high-train low (LHTL) effectiveness is improved when daily training is guided by heart rate variability (HRV).Methods: Twenty-four elite Nordic skiers took part in a 15-day LHTL study and were randomized into a HRV-guided training hypoxic group (H-HRV, n = 9, sleeping in normobaric hypoxia, FiO2 = 15.0%) and two predefined training groups sleeping either in hypoxia (H, n = 9, FiO2 = 15.0%) or normoxia (N, n = 6). HRV and training loads (TL) were recorded daily. Prior (Pre), one (Post-1), and 21 days (Post-21) following LHTL, athletes performed a 10-km roller-ski test, and a treadmill test for determination of [Formula: see text] was performed at Pre and Post-1.Results: Some HRV parameters measured in supine position were different between H-HRV and H: low and high (HF) frequency power in absolute (ms2) (16.0 ± 35.1 vs. 137.0 ± 54.9%, p = 0.05) and normalized units (- 3.8 ± 10.1 vs. 53.0 ± 19.5%, p = 0.02), HF(nu) (6.3 ± 6.8 vs. - 13.7 ± 8.0%, p = 0.03) as well as heart rate (3.7 ± 6.3 vs. 12.3 ± 4.1%, p = 0.008). At Post-1, [Formula: see text] was improved in H-HRV and H (3.8 ± 3.1%; p = 0.02 vs. 3.0 ± 4.4%; p = 0.08) but not in N (0.9 ± 5.1%; p = 0.7). Only H-HRV improved the roller-ski performance at Post-21 (- 2.7 ± 3.6%, p = 0.05).Conclusion: The daily individualization of TL reduced the decrease in autonomic nervous system parasympathetic activity commonly associated with LHTL. The improved performance and oxygen consumption in the two LHTL groups confirm the effectiveness of LHTL even in elite endurance athletes. [ABSTRACT FROM AUTHOR]

We assessed the time course of running mechanical alterations during an 800-m. On a 200-m indoor track, 18 physical education students performed an 800-m self-paced run. Once per lap, ground reaction forces were measured by a 5-m-long force platform system, and used to determine running kinetics/kinematics and spring-mass characteristics. Compared with 100 m (19.4±1.8 km.h-1) running velocity progressively decreased at 300, 500 m but levelled-off at 700 m marks (-5.7±4.6, -10.4 ± 8 .3, and -9.1 ±13.5%, respectively; P< 0.001). Stride length (- 8.5 ± 2.3 %, P< 0.01) and frequency (-1.0 ± 1.5 %, P = 0.05) along with peak braking (-7.5 ±4.4%, P<0.05) and push-off forces (-5.1 ±7.2%, P<0.05) decreased from 100 m to 700 m. Peak vertical forces (-3.0 ± 2.7 %;P>0.05) and leg compression (+2.8 ±3.9%; P> 0.05) remained unchanged, whereas centre of mass vertical displacement (+ 24.0 ± 7.0%; P<0.001) increased during the run. Vertical stiffness decreased (-18.1 ±4.4%; P<0.001), whereas leg stiffness was unchanged (-3.2 ±4.6%; P>0.05). During an 800 m by physical education students, highest running velocity was achieved early during the run, with a progressive decrease in the second half of the trial. While vertical ground force characteristics remained unchanged, non-specialist runners produced lower peak braking and push-off forces, in turn leading to shorter stride length. Spring-mass model characteristics changed toward lower vertical stiffness values, whereas leg stiffness did not change. [ABSTRACT FROM AUTHOR]