To determine the change in mechanical properties of sprinting performance across an 8-week off-season period in professional rugby league players.
Design: Repeated measuresMethods: Twenty-six professional rugby league players from a single rugby league team competing in Super League completed two assessments of linear sprint performance during final week of the season and second week of preseason. Linear split times were used to model the horizontal force-velocity profile and determine theoretical maximal force (F0), velocity (V0) and power (Pmax).
Results:Our result indicated moderate-to-large increases in split times at each distance across the off-season period (ES = 0.86 to 1.24; most likely), indicative of a reduced sprinting ability. Furthermore, small reductions in F0 (ES -0.34 to -0.57; likely to very likely) were observed, whilst the reduction in V0 (ES = -0.81; most likely) and Pmax (ES = -0.62 to -1.03; most likely) were considered moderate in magnitude.
Conclusions:An 8-week off-season period elicited negative changes in linear sprint times and the horizontal force-velocity profile of professional rugby league players. Such findings might have implications for preseason training loads and therefore, the off-season period requires careful consideration by practitioners and clinicians with regards to content and monitoring.
Objective: The purpose of this study was to establish the inter-day reliability of several performance variables measured during a 2 × 6 s sprint on a Wattbike cycle ergometer in male rugby players. Reliablilty was assessed against an 'analytical goal' of detecting meaningful changes that might be expected with fatigue in rugby.
Design & Methods:Sixteen male rugby players performed three trials of the protocol on different days seperated by a mimimum of 48 h. The protocol comprised 2 × 6 s 'all out' cycle sprints with 90 s recovery between efforts. Typical error (TE), coefficient of variation (CV), smallest worthwhile change (SWC) and moderate change (MC) were calculated between each trial for seven variables.Results: Peak Power output significantly increased from the first to the third trial (3.3-4.4 %), whilst all variables had better reliability from trials 2-3 than 1-2. Mean power (3.7%), peak power (4.2%) and total distance (2.7%) had a CV% lower than decrements observed with team sport fatigue (~5%), however only total work had a TE (2.1 kJ) lower than the smallest worthwhile change (4.6 kJ) while the remainder were lower than the moderate worthwhile change.
Conclusion:Assuming one complete habituation trial is completed, total work appears to be the most reliable variable capable of detecting a worthwhile change in performance. We recommend using this variable to monitor fatigue in rugby players.(Journal of Trainology 2018;7:1-4)
Objectives: The main objective of this study was to determine the concurrent validity between a hand-held (HHD) and mounted hand-held dynamometer (MHHD) for assessing isometric neck strength.Design: Observational design.
Setting: UK-based semiprofessional rugby clubParticipants: Nineteen semi-professional rugby players (age = 26 ± 5 years, stature = 186.5 ± 6.5 cm, body mass = 98.7 ± 12.8 kg).Main outcome measures: Concurrent validity (i.e., limits of agreement, correlation) between HHD and MHHD, the intrarater reliability (intra-class correlation, ICC) and comparison between playing positions.Results: Absolute peak and mean peak force were systematically lower when using the HHD compared to MHHD, with the mean bias ranging from -1.8 to -3.8 kgf (P <0.05). Differences were not evident for flexion when applying the correction equations (-0.5 to 2.1 kgf, P >0.05) but remained for extension. Correlations between methods were large-to-very large; the ICCs for both methods were good (ICC = 0.72-0.89), with no difference between positions (P >0.05).
Conclusion:The concurrent validity of HHD was considered acceptable when compared to the MHHD and the correction equation was applied. Both methods are reliable and useful for assessing neck strength in rugby players, though, caution is needed when determining strength during neck extension.
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