Shorter constant work rate cycling tests as proxies for longer tests in highly trained cyclists.

Severe-intensity constant work rate (CWR) cycling tests simulate the high-intensity competition environment and are useful for monitoring training progression and adaptation, yet impose significant physiological and psychological strain, require substantial recovery, and may disrupt athlete training or competition preparation. A brief, minimally fatiguing test providing comparable information is desirable. Purpose To determine whether physiological variables measured during, and functional decline in maximal power output immediately after, a 2-min CWR test can act as a proxy for 4-min test outcomes. Methods Physiological stress ([Formula: see text] kinetics, heart rate, blood lactate concentrations ([La-]b)) was monitored and performance fatigability was estimated (as pre-to-post-CWR changes in 10-s sprint power) during 2- and 4-min CWR tests in 16 high-level cyclists ([Formula: see text] ml∙kg-1∙min-1). The relationship between the 2- and 4-min CWR tests and the physiological variables that best relate to the performance fatigability were investigated. Results The 2-min CWR test evoked a smaller decline in sprint mechanical power (32% vs. 47%, p<0.001). Both the physiological variables (r = 0.66-0.96) and sprint mechanical power (r = 0.67-0.92) were independently and strongly correlated between 2- and 4-min tests. Differences in [Formula: see text] and [La-]b in both CWR tests were strongly associated with the decline in sprint mechanical power. Conclusion Strong correlations between 2- and 4-min severe-intensity CWR test outcomes indicated that the shorter test can be used as a proxy for the longer test. A shorter test may be more practical within the elite performance environment due to lower physiological stress and performance fatigability and should have less impact on subsequent training and competition preparation.

Quantification of maximal power output in well-trained cyclists.

This study aimed to compare mechanical variables derived from torque-cadence and power-cadence profiles established from different cycle ergometer modes (isoinertial and isokinetic) and modelling procedures (second- and third-order polynomials), whilst employing a novel method to validate the theoretical maximal power output (Pmax). Nineteen well-trained cyclists (n = 12 males) completed two experimental sessions comprising six, 6-s maximal isoinertial or isokinetic cycling sprints. Maximal pedal strokes were extracted to construct power-cadence relationships using second- and third-order polynomials. A 6-s sprint at the optimal cadence (Fopt) or optimal resistance (Topt) was performed to assess construct validity of Pmax. No differences were found in the mechanical parameters when derived from isokinetic (Pmax = 1311 ± 415, Fopt = 118 ± 12) or isoinertial modes (Pmax = 1320 ± 421, Fopt = 116 ± 19). However, R2 improved (P < 0.02) when derived from isoinertial sprints. Third-order polynomial modelling improved goodness of fit values (Standard Error, adjusted R2), but derived similar mechanical parameters. Finally, peak power output during the optimised sprint did not significantly differ from the theoretical Pmax in both cycling modes, thus providing construct validity. The most accurate P-C profile can be derived from isoinertial cycling sprints, modelled using third-order polynomial equations.

Correction to: Applied Physiology of Rugby League.

The original article 'Science of Rugby League Football: A Review'.

Comparing Global Positioning System and Global Navigation Satellite System Measures of Team-Sport Movements.

PURPOSE: To compare data from conventional global positioning system (GPS-) and new global navigation satellite system (GNSS-) enabled tracking devices and to examine the interunit reliability of GNSS devices. METHODS: Interdevice differences between 10-Hz GPS and GNSS devices were examined during laps (n = 40) of a simulated game circuit and during elite hockey matches (n = 21); GNSS interunit reliability was also examined during laps of the simulated game circuit. Differences in distance values and measures in 3 velocity categories (low <3 m·s-1; moderate 3-5 m·s-1; and high >5 m·s-1) and acceleration/deceleration counts (>1.46 and <-1.46 m·s-2) were examined using 1-way analysis of variance. Interunit GNSS reliability was examined using the coefficient of variation (CV) and intraclass correlation coefficient. RESULTS: Interdevice differences (P < .05) were found for measures of peak deceleration, low-speed distance, percentage of total distance at low speed, and deceleration count during the simulated game circuit and for all measures except total distance and low-speed distance during hockey matches. Interunit (GNSS) differences (P < .05) were not found. The coefficient of variation was below 5% for total distance, average and peak speeds and distance and percentage of total distance of low-speed running. The GNSS devices had a lower horizontal dilution of precision score than GPS devices in all conditions. CONCLUSIONS: These findings suggest that GNSS devices may be more sensitive than GPS devices in quantifying the physical demands of team-sport movements, but further study into the accuracy of GNSS devices is required.

A time-motion analysis of professional rugby league match-play.

The aim of this study was to analyse movement patterns of professional rugby league players during matches played as part of Australia's National Rugby League (NRL) competition. The movement patterns of one player from each of the three positional groups (hit-up forwards, adjustables, and outside backs) during three competition matches were examined using time-motion analysis. Positional groups differed in distances covered (P = 0.001), and covered shorter distances than those described in earlier research. The mean exercise-to-rest ratio was 1:6 for the outside backs and hit-up forwards and 1:5 for the adjustables. However, such ratios did not reflect the most demanding periods of the game, which included repeated high-intensity efforts interspersed with recovery periods of short duration. These periods of repeated high-intensity exercise often occurred at crucial phases of the game, when players were either attacking or defending the try-line. Furthermore, patterns of movement during repeated high-intensity periods of play differed among positional groups. To prepare for the most highly intense periods of match-play, professional rugby league players should adopt position-specific training that includes the highest and lowest exercise-to-rest ratios likely to be experienced in competition.

Applied physiology of rugby league.

Rugby league football is played in several countries worldwide. A rugby league team consists of 13 players (6 forwards and 7 backs), with matches played over two 40-minute halves separated by a 10-minute rest interval. Several studies have documented the physiological capacities of rugby league players and the physiological demands of competition, with the physiological capacities of players and the physiological demands of competition increasing as the playing level is increased. However, there is also evidence to suggest that the physiological capacities of players may deteriorate as the season progresses, with reductions in muscular power and maximal aerobic power and increases in skinfold thickness occurring towards the end of the rugby league season, when training loads are lowest and match loads and injury rates are at their highest. Player fatigue and playing intensity have been suggested to contribute to injuries in rugby league, with a recent study reporting a significant correlation (r=0.74) between match injury rates and playing intensity in semi-professional rugby league players. Studies have also reported a higher risk of injury in players with low 10-m and 40-m speed, while players with a low maximal aerobic power had a greater risk of sustaining a contact injury. Furthermore, players who completed <18 weeks of training prior to sustaining their initial injury were at greater risk of sustaining a subsequent injury. These findings provide some explanation for the high incidence of fatigue-related injuries in rugby league players and highlight the importance of speed and endurance training to reduce the incidence of injury in rugby league players. To date, most, but not all, studies have investigated the movement patterns and physiological demands of rugby league competition, with little emphasis on how training activities simulate the competition environment. An understanding of the movement patterns and physiological demands of specific individual positions during training and competition would allow the development of strength and conditioning programmes to meet the specific requirements of these positions. In addition, further research is required to provide information on the repeated effort demands of rugby league. A test that assesses repeated effort performance and employs distances, tackles and intensities specific to rugby league, while also simulating work-to-rest ratios similar to rugby league competition, is warranted.