Rugby Union

Introduction
Rugby union is a sport which makes use of the aerobic and anaerobic metabolic systems to a vast extent. 1-3
While playing an 80 min match, studies of time-motion analysis 1-3 show that around 120-125 brief and intense actions (∼5 s) are performed by the trained and professional rugby forwards, whereas backs only perform 50-70 work periods in comparison. These analysis indicate that it is essential for rugby players to repeat the high intensity efforts with a very short recovery span.
However, Rugby is not an easy sport and tends to demand a lot from the players with the variety of body movements and positions that it involves. Duthie et al. 6 highlighted the differences in the forward and back body masses which were seen as 107.3±8.3 kg for the forwards and 84.5±7.9 kg for the backs. Quarie et al. 7 took into account the contrasts in the update of oxygen which turned out to be ˙VO2max (54.9±3.9mLkg−1 min−1 vs. 59.9±2.5mLkg−1 min−1) between the two segments. The metabolic demands in the game of rugby are very distinct and the forwards involving actions like rucking, mauling, scrimmaging, end up spending more time and intensity, which is about 13% of the total time, as compared to the backs which involve only up to 4.5% of the total time. 2, 3.
The ratio of work-rest in the forwards (mean work ∼5 s, mean rest ∼30–40 s)2 shows that the forwards have the ability to complete work segments that last for over 20s, and about 20% of the work bouts are continued by periods of rest which are of an equal or shorter time period. The forwards however, have chances of experiencing fatigue due to hydrogen accumulation(H+) mainly because the level of energy in this segment is supplied by the anaerobic glycolysis and the aerobic metabolism. 2 On the other hand, the work rest ratio for the backs (meanwork∼5 s, mean rest∼80–110 s)2 shows that the creatine phosphate (PCr) system plays a vital role. The fatigue resistance does not have much of an effect to limit the backs because the back players tend to work for a shorter span of time which is about 10seconds long and thus get a rest period of almost 90% of the work. Hence shorter work is followed by an equal or greater time period of rest.
Methods
A study was conducted wherby seven fully trained rugby players were asked to participate. Amongst these were four forwards and three backwards and then average age was around 20.6±0.5 yrs, the average height being around 181.9±10.0 cm and the mean mass of the body of around 94.5±12.8 kg.Each player had am experience of playing for at least 5 years therefore they were used to the procedures taking place. The study was carried out in the regular season where test sessions were conducted at least 2 days after the preceding match. During this time period, the players received physical training sessions and were focused on their skills and tactics. About 8 training session wee held every week which was followed by a championship game on the weekend. Players were made to sign written agreements after being briefed about the risks and benefits involved in the experiment. The study was also approved by the local Ethics Committee.
Three test sessions were carried out over 3 a week’s time. All the participants were made to perform a maximum incremental exhaustion test so as to derive the maximum aerobic speed of the players. The velocity at the initial stage was kept to 8hmh-1 and this gradually increased by about 0.5kmh-1 per minute. The running velocity of the players was adjusted according to the normal auditory pacing signals and the visual indicators which were marked on the running tracks at an interval of 20 minutes. Billat and Koralsztein stated that MAS was calculated and the velocity of the last stage was completed .
There were two experimental sessions which were different only in terms of the recovery mode (AR and PR). Each players participated in both the sessions conducted and took part in a 30 min match, abiding by all the rules outlines by the International Board Rugby, without any clear instructions on the recovery mode.A pre test was held before each match and was followed by a post test by a specific repeated sprint rugby test which was also known as the Narbonne test , after every 10 minutes of the match.
Statistical analysis
The mean and the standard deviation was then calculated for each variable. Apart from the HR during the match, all other statistics were non parametric and after the normal and equal variance tests were conducted and rechecked for the data. The changes found in the performance of the two recovery conditions, AR and PR, during the Narbonne test measuring the scrum forces, agility and sprint times were analyzed by Friedman Repeated Measures test on Ranks. HR during the match was calculated by One-way Repeated Measures Analysis of Varaince. A post hoc Student–Neumann–Keuls test was carried out when the effects were measured. This test aimed to measure the differences between the means of pairs. (SigmaStat 1.0, Jandel Corporation, San Rafael, CA, USA). Statistical significance was derived at a α level of p < 0.05.

Discussion
The Narbonne test basically shows the active recovery impairs performance as more important than passive recovery. Figure 3 indicated the evolution of the heart rate values while the Narbonne test in A which shows the pretest and B which shows post test. The clear difference between A and B is evident before the scrum and after the sprint, the higher sprint fatigue index and the slow sprint times. Even though the heart rates while the Narbonne test was taking place were higher in active rather than passive recovery in the pre test, these results were weakened in the post test.


The reduction in PCr resynthesis throughout the recovery process is the result of restricted oxygen supplies between lactate oxidation, Pcr resynthesis and the cost of increasing O2
for the additional exercise as the PCr resynthesis depends on oxidative processes. Dupont et al.10 reported that during the passive recovery, the increase in the reoxygenation of Myoglobin, PCr resynthesis and improved exercise performance may be the result of decline in muscle oxygenation. Further he (Dupont et al.9,10) proved that passive recovery during high intensity bout takes more time to exhaust if carried out at 120% of ‘V O2max [cycling and running protocols (set of rules to be followed)]. It was indicated in active recovery by Spencer et al.11 (25 s at 32% ‘VO2max) that there is a strong attraction towards lower post exercise (PCr). In accordance to the result given by Dupont et al.9,10 and Spencer et al.11 it was known that a slower PCr depeletion and higher PCr resynthesis throughout passive recovery are the controlling mechanism that maintain performance during the Narbonne test.













Similarly, Rossiter et al.17 showed a close relation between muscles (PCr) pulmonary and kinetics vo2 and the relation between both moderate and heavy intensity exercise. Jones et al.18 demonstrated that when the heavy exercise was initiated from moderate intensity exercise as compared to when it was started from rest, the fall in PCr was found to be longer. Today’s study seems like active recovery is almost same or equal to the moderate intensity exercise while the rest position can be compared to the passive recovery. Acc to dup these results proved that a faster VO2 adjustment throughout the recurring exercise may lessen the decrement in PCr, as it is in passive recovery. The resulted proves with the passive recovery introduce a much better recovery between the maximum recurring efforts and because of the rugby match the development of fatigue is decreased. This result was confirmed by the passive recovery in which fatigue was measured and found to be low both during the pretest and post test (less total sprint time and fatigue index). After the game, regardless of verbal communications and encouragement, the greater fatigue index seem to be a out of box conclusion and could represent some sort of quick.


In pre test the heart rate is found to be higher in active recovery instead of in passive recovery. The higher rate in active recovery may result in increasing the competition for blood supply between the hearts and exercising muscles. During active recovery the skeletal muscle pump more utilized because of its greater use as compare to the passive recovery.


The heart rate values that were recorded in passive recovery were found to be higher in post test. The dissimilarity between active a passive recovery in post test can be emphases by lesser heart rates values in active recovery as compare to the pre test. In answer to the moderate intensity through out recovery. 20 the peripheral resistances is extremely less and blood flow is increased. Another explanation is that during the active recover the average work load on the player is greater then in normal condition, because of less amont of time and the work load is found to be zero.

In active recovery, the pump rate of heart is heavily dependent on the average workload as it is as their relation is directly proportional to each other. As we play a game or a match the cardiac response is decreased because of cardiac reserve is decreased, our stamina gets lower and we start feeling tired.

Sprint performance is not damaged when it is followed by serious resistance exercise such as scrimmaging, it was indicated by Deutsch and Lloyd21. Also the dissimilarity in quick printing followed by scrimmaging (vigorous straggle) is in agreement with the results.
To conclude, when Narbonne test was conducted for before the game-play was initiated and after it was ended, lower performance was evident due to active recovery. This was not the case with passive recovery. During repeated sprints, the active recovery showed greater fatigue index, which is opposite to passive recovery, i.e 7.3% vs. 4.3%.in post-test and 11.5% vs. 6.7% in pre-test.