Anthropometry and physical characteristics in English premiership women’s rugby

Rugby union is a field-based team sport characterized by repeated high-intensity activities (sprinting, agility and collisions) combined with periods of lower intensity activities (walking and jogging). Based on positional differences and match demands, athletes are generally grouped as forwards (front row, second row and back row) and backs (scrum half, inside backs and outside backs). English premiership women’s rugby union has been continually growing in popularity and gaining participants every year. Besides increases in participation, the standard of women’s rugby union has improved due to increased investment, which enabled international women rugby players to become semi or fully professional. The growth of women’s rugby union has naturally led to an increase in scientific interest and research. Research into women’s rugby union has focused on match demands, anthropometry, and physical characteristics.

In study 1, a systematic search of literature was undertaken to review existing research regarding identifying the characteristics to become a competitive women’s rugby union player. The result revealed that a total of 25 studies focused on identifying and discussing match demands, anthropometry, and physical characteristics. Forwards were found to have participated in more collisions, were heavier, and demonstrated greater absolute strength. Backs engaged in more high-speed running, were leaner, aerobically fitter, and relatively stronger.

In study 2, anthropometry using dual-X-ray absorptiometry and physical characteristics made up of strength and power tests (countermovement jump, drop jump, and isometric mid-thigh pull) were investigated and grouped by position. Overall, forwards had significantly (p < 0.01) higher body mass, fat mass, lean mass, bone mineral content, and take-off momentum, and backs had significantly higher (p < 0.01, d > 0.5) jump height, reactive strength index modified, and shorter drop jump contact time.

In study 3, Seasonal changes of anthropometry and physical characteristics were observed throughout pre-, mid- and post-season. Based on the tests used in study 1, statistically significant differences (p < 0.01) or moderate to large practical differences (d > 0.5) in lean mass (mid- > pre-season), reactive strength index modified (post- > mid-season), time to take-off (post- < mid-season) and drop jump flight time (pre- < mid- and post-season) were shown among forwards. Backs were found to have statistically significant differences (p < 0.01) or moderate to large practical differences (d > 0.5) in lean mass (post- > pre-season) and drop jump flight time (pre- < mid- and post-season) throughout the season.

In study 4, sprint performance and kinematics were discussed between positions and fast, moderate, and slow groups based on the split times of acceleration and top speed were formed. Findings demonstrate that during acceleration backs performed statistically significantly higher velocity, step rate, step velocity, and shorter contact time (p < 0.05, g > 0.80). Forwards, despite being slower, still produced moderately higher to statistically significantly higher initial and top speed momentum (p < 0.05 or g > 0.7) due to higher body mass. When comparing different speed groups, faster athletes used a shorter contact time (g = 1.58 to 1.64) to generate a moderate to larger toe-off thigh angle (g =0.57 to 1.00), and a longer flight length (g =1.21 to 1.34) to create a longer step length (g = 1.12 to 1.19) in both acceleration and top speed.

In study 5, seasonal changes of sprint performance and kinematics were observed throughout pre-, mid- and post-season. Velocity, initial momentum, flight time, toe off distance, and flight length statistically significantly decreased (p < 0.05, g > 1.33) in acceleration from pre- to mid-season. A similar trend was found in top speed, and step length, step velocity, foot strike distance, toe-off distance, and contact length all statistically significantly decreased (p < 0.05, g > 1.87) from pre-to mid-season. From mid- to post-season, trivial practical differences were found in acceleration velocity but large practical differences were observed in contact time, flight time, toe-off distance, and flight length (g > 0.90). Top speed had a moderate increase (g = 0.68) from mid- to post-season, and step velocity, foot strike distance, toe-off distance, contact and flight length all statistically significantly increased (p < 0.05, g > 1.38).

In study 6, change of direction ability and relationship was determined between positions. Further investigation using different speed groups was again undertaken and were based on the time of the 505 test, again split into thirds. Dominant side of the 505 test was based on the faster time compared between both left and right turn recorded during the test. Backs demonstrated statistically significantly faster 505 times in both the dominate and non-dominate side compared to forwards (p < 0.05, g = 0.93 and 1.06). However, no statistically significant differences were found in change of direction deficit between positions. Forwards’ dominant side 505 time demonstrated a significant positive relationship (r = 0.67) with body mass. Furthermore, forwards’ linear velocity had significant negative relationship (r = -0.70) with dominate side 505 time, but a positive relationship with dominate side change of direction deficit (r = 0.60). In contrast, no significant relationship in backs was found between linear velocity and dominate side 505 for backs. Backs linear sprint velocity was shown to have a significant positive relationship with both dominate (r = 0.60) and non-dominate side (r = 0.71) change of direction deficit. When observing speed group differences, faster athletes had statistically significantly lighter body mass, faster linear sprint, and non-dominate side 505 time (p < 0.05, g = 1.35 to 2.15).

In study 7, seasonal changes of change of direction ability were observed between mid- and post-season. No pre-season data was collected due to the impact the COVID 19 pandemic had to professional sport. Besides large practical increase in body mass and initial momentum, only small practical increases was found in 505 time on both the dominate and non-dominate side (g = 0.37 and 0.41).

In conclusion, the findings of this thesis determined the match demands that women rugby players face in different position. The results demonstrated that forwards, although slower than backs, have higher lean mass and fat mass, generated higher momentum and absolute peak force, which support positional match demands for forwards to face more frequent collisions. Backs were found to be leaner, faster in both linear and change of direction sprints, and were able to produce relative peak force similar to forwards. In addition, the results supported match demand studies identifying backs have more opportunity to reach high speed but also need the strength to face higher collision forces. The longitudinal studies determined that anthropometry characteristics are maintained throughout the season with only a small practical increase in lean mass from pre- to mid-season. However, in physical characteristics, both power tests and sprint performance results showed a decrease from pre- to mid-season and an increase from mid- to post-season. Lastly, as both sprinting and change of direction are motor skills rather than proxy measures of force and power output, understanding the kinematics in sprinting and change of direction can be used to identify common characteristics in fast athletes from which training can be devised and monitored. Overall, these finding represent novel contributions to women’s rugby union literature as well as providing insights and baseline data for future research and practitioners to make informed recruitment and training decisions.