Heart Rate-Index Estimates Oxygen Uptake, Energy Expenditure and Aerobic Fitness in Rugby Players.

The purpose of the study was to verify the suitability of heart rate-index (HRindex) in predicting submaximal oxygen consumption (VO2), energy expenditure (EE) and maximal oxygen consumption (VO2max) during treadmill running in rugby players. Fifteen professional rugby players (99.8 ± 12.7 kg, 1.85 ± 0.09 m) performed a running incremental test while VO2 (breath-by-breath) and heart rate (HR) were measured. HRindex was calculated (actual HR/resting HR) to predict submaximal and maximal VO2 ({[(HRindex x 6)-5.0] x (3.5 body weight)}) and EE. Measured and predicted VO2 and EE were compared by two-way RM-ANOVA (method, speed), correlation and Bland-Altman analysis. Measured and predicted VO2max were compared by paired t-test, correlation and Bland-Altman analysis. Submaximal VO2 and EE significantly increased (baseline VO2: 8.1 ± 1.6 ml·kg-1·min-1VO2max: 46.8 ± 4.3 ml·kg-1·min-1, baseline EE: 0.03 ± 0.01 kcal·kg-1·min-1, peak EE: 0.23 ± 0.03 kcal·kg-1·min-1) as a function of speed (p < 0.001 and p < 0.001 for VO2 and EE respectively) yet measured and predicted values at equal treadmill speeds were not significantly different (p = 0.17; p = 0.16) and highly correlated (r = 0.95; r = 0.94). The Bland-Altman analysis confirmed a non-significant bias between measured and estimated VO2 (measured: 40.3 ± 10.7, estimated: 40.7 ± 10.1 ml·kg-1·min-1, bias = 1.35 ml·kg-1·min-1, z = 1.12, precision = 3.39 ml·kg-1·min-1) and EE (measured: 20.0 ± 0.05 kcal·kg-1·min-1, estimated: 20.0 ± 0.05 kcal·kg-1·min-1, bias = 0.00 kcal·kg-1·min-1, z = 0.04, precision = 0.02 kcal·kg-1·min-1). Estimated and predicted VO2max were not statistically different (p = 0.91), highly correlated (r = 0.96), and showed a non-significant bias (bias = 0.17, z = 0.22, precision = 1.29 ml·kg-1·min-1). HRindex is a valid field method to track VO2, EE and VO2max during running in rugby players.

Player's success prediction in rugby union: From youth performance to senior level placing.

OBJECTIVES: The study questioned if and to what extent specific anthropometric and functional characteristics measured in youth draft camps, can accurately predict subsequent career progression in rugby union. DESIGN: Original research. METHODS: Anthropometric and functional characteristics of 531 male players (U16) were retrospectively analysed in relation to senior level team representation at age 21-24. Players were classified as International (Int: National team and international clubs) or National (Nat: 1st, 2nd and other divisions and dropout). Multivariate analysis of variance (one-way MANOVA) tested differences between Int and Nat, along a combination of anthropometric (body mass, height, body fat, fat-free mass) and functional variables (SJ, CMJ, t15m, t30m, VO2max). A discriminant function (DF) was determined to predict group assignment based on the linear combination of variables that best discriminate groups. Correct level assignment was expressed as % hit rate. RESULTS: A combination of anthropometric and functional characteristics reflects future level assignment (Int vs. Nat). Players' success can be accurately predicted (hit rate=81% and 77% for Int and Nat respectively) by a DF that combines anthropometric and functional variables as measured at ∼15 years of age, percent body fat and speed being the most influential predictors of group stratification. CONCLUSIONS: Within a group of 15 year-olds with exceptional physical characteristics, future players' success can be predicted using a linear combination of anthropometric and functional variables, among which a lower percent body fat and higher speed over a 15m sprint provide the most important predictors of the highest career success.

Anthropometrics of Italian Senior Male Rugby Union Players: From Elite to Second Division.

UNLABELLED: Anthropometric evaluation of athletes is necessary to optimize talent identification and player development. OBJECTIVES: To provide a specific anthropometric reference database of senior male rugby players competing at different levels in the southern European region. DESIGN: Cross-sectional. METHODS: In 362 professional players (25 ± 4 y; 138 Italian national team, 97 first-division, and 127 second-division national championships) the authors measured mass, stature, and percentage body fat (plicometry). Mean, SD, and coefficient of variation were calculated for forwards and backs and for positional subgroups. Binomial logistic regression and receiver-operating-characteristic curve were performed to assess which variables best predicted level assignment (international vs national level). RESULTS: For all competitive levels forwards were significantly heavier and taller and had a larger percentage body fat and fat-free mass than backs. The lower the competitive level, the higher the within-role variability observed; furthermore, players in a specific positional subgroup were lighter, shorter, and fatter and had less fat-free mass. Fatfree mass is the variable that best predicts the likelihood of being classified as an international or national player (cutoff value 79.54 kg). CONCLUSIONS: The data confirm the specificity in the physical requirements of rugby in individual playing positions at all competitive levels and document significant differences among elite and 1st- and 2nd-division players in the same positional role. These differences may reflect the variable technical abilities, selection, training practices, and requirements of the game among these categories.