Aerobic exercise physiology in a professional rugby union team

In professional rugby, different positional roles may require different levels of aerobic fitness. Forward and backline players from a team of elite rugby players were tested to evaluate the differences between the two groups.

28 male players, 15 backs and 13 forwards, underwent maximal treadmill cardiopulmonary exercise testing (CPX), lung spirometry, a 3 km timed run, and body fat measurement.

Peak oxygen uptake was higher in backs than in forwards (peak VO(2) 48.3+/-2.1 vs. 41.2+/-2.7 ml kg(-1) min(-1), P<0.05) with no significant difference in peak respiratory exchange ratio (1.08+/-0.02 vs. 1.07+/-0.02, P=NS), exercise time (1306+/-39.7 vs. 1217+/-25.1 s, P=NS) or time for 3 km run (667.5+/-14.1 vs. 699.0+/-20.7 s, P=NS). However, the forwards were taller and heavier (height 190.2+/-2.2 vs. 179.5+/-1.3 cm, P<0.001, body mass 104+/-2.4 vs. 86.3+/-1.7 kg, P<0.0001) and had a higher fat content (body fat percentage 12.8+/-0.8 vs. 9.7+/-0.6%, P<0.01) and forced expiratory volume in 1 s (FEV1, 4.9+/-0.1 vs. 4.5+/-0.2 l, P<0.05). There was a significant negative correlation between peak VO(2), 3 km run time (r=-0.45, P<0.05) and weight (r=-0.54, P<0.003) for all subjects.

Backline players have a higher peak oxygen uptake per kilogram than forwards, although the cardiopulmonary exercise test duration, degree of anaerobic metabolism and 3 km run time are not significantly different. These results could be due to the two groups' different body structure, being shorter, lighter and having a lower percentage body fat. These differences, which are likely to be a result of selection for specific roles in the game, should be taken into account when evaluating aerobic fitness within a rugby team.