Differences in the vertical and horizontal force-velocity profile between academy and senior professional rugby league players, and the implications for strength and speed training

Abstract

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.

Postural evaluation and risk of musculoskeletal injuries in professional male rugby players: a proof-of-principle study

“…1,2 The incidence of injuries among professional rugby players seems to vary between 27 and 218 per 1000 hours of match and between 2 and 6 per 1000 hours of training in the studies analyzed; for amateur rugby players the incidence drops to about 47 per 1000 match hours. 2,[4][5][6][7][8][9][10] Although rugby is a contact sport, most injuries affect the muscle-tendon structures and ligaments of the lower limbs through indirect trauma. 2,4,5 Williams et al, in 2017, published an interesting article that demonstrates the correlation between games played in the last 12 months, games played in the last month and injury predisposition: players who have played less than 15 times or more than 35 times in the last year present an increased risk compared to teammates.…”