Hayden Knowles’s scientific contributions

The purpose of this study was to examine the differences in physical performance and game-specific skill demands between 5 positional groups in a professional rugby league team. Positional groups consisted of the backs (n = 8), forwards (n = 8), fullback (n = 7), hooker (n = 8), and service players (n = 8). Time-motion analysis was used to determine physical performance measures (exercise intensity, distance travelled, time, frequency, and speed measures) and game-specific skill measures (ball carries, supports, ball touches, play the balls, and tackling indices) per minute of playing time. The main finding was that the fullback completed more very high-intensity running (VHIR) because of more support runs when compared to all other positional groups (p = 0.017). THe VHIR (p = 0.004) and sprinting indices (p < 0.002) were also greater in the second half of a match for the fullback than in any other positional group. The hooker spent more time jogging than the backs and forwards (p < 0.001) and touched the ball on more occasions than any other positional group (p < 0.001). The backs spent more time walking than the forwards, hooker, and service players (p < 0.001). The forwards, hooker, and service players completed more tackles per minute during a match than the backs and fullback (p < 0.001). The fullback and forwards also ran the ball on more occasions than the backs, hooker, and service players did (p < 0.001). These results show that positional roles play an important part in determining the amount of physical and game-specific skill involvement during match play.

The purpose of this study was to examine differences in physical performance and game-specific skills between elite and semi-elite rugby league players during match-play. Time-motion analysis was used to determine physical and game-specific skill match demands in 17 elite and 22 semi-elite rugby league players. Physical performance (time, intensity of exercise, frequency, repeated-sprint ability, and speed measures) and game-specific skill measures (ball carries, supports, ball touches, play-the-balls, and tackles) were recorded per minute of playing time. The main findings were that total intensity (elite: 108.9 +/- 10.6 m . min(-1); semi-elite: 102.3 +/- 9.7 m . min(-1)), high-intensity exercise (elite: 36.7 +/- 9.8 m . min(-1); semi-elite: 29.6 +/- 7.8 m . min(-1)), mean playing speed (elite: 6.6 +/- 0.6 km . h(-1); semi-elite: 6.2 +/- 0.6 km . h(-1)), and support play (elite: 0.29 +/- 0.16 . min(-1); semi-elite: 0.15 +/- 0.09 . min(-1)) were all higher during first-half match-play in the elite than semi-elite players (P < 0.01). The elite players experienced decrements in most physical performance measures during the second-half of match-play (P < 0.01), which was not evident in the semi-elite players (P > 0.01). There were no differences in most physical performance and game-specific skill measures for the match between the two playing standards. These results show that while the two standards of competition have similar game-specific skills and physical demands during a match, there is variation within a match according to standard. Specifically, the higher physical demands placed on elite players during the first half could result in the earlier onset of physical fatigue towards the end of a match.