Acute immune response of elite rugby union players to Super 15 Match-play

Abstract

The present study observed the immunological response to Super 15 match-play by analyzing weekly work load, match statistics, and [s-IgA] of elite rugby union players (n = 23, age 24.8 ± 2.9 years; stature 185.6 ± 6.8 cm; weight 100.7 ± 11.2 kg, Super 15 career of 56.3 ± 24.7 rugby games) competing in three Super 15 rugby matches (Match 10, Match 12 and Match 15). Saliva samples (0.5 ml) were collected at 32 hours pre match, 1 hour post match play and 32 hours post match play, using the Individual Profiling device (IPRO) (Oxfordshire, UK) to determine the [s-IgA]. Training and game loads (RPE x Duration) were recorded to calculate weekly workloads across the Super Rugby season. A substantial increase in [s-IgA] was observed pre 32 hour match play and 1 hour post match play in Match 10 for backs (45.8 ± 22.6 %, ES 1.78 ± 0.96) and forwards (49.3 ± 25.8 %, ES 1.29 ± 0.74), and pre 32 hour match play and 32 hours post match in Match 10 (23.1 ± 50.8 %, ES 0.98 ± 1.93) for backs and forwards (50.9 ± 38.9 %, ES 1.32 ± 1.06) and Match 12 for backs (54.2 ± 45.2 %, ES 1.06 ± 0.92) and forwards (40.3 ± 32.6 %, ES 0.89 ± 0.74) compared to all other time points. Acute weekly changes (week to week changes) in physical loads found substantial decreases during Match 10 for backs (-26.1 ± 12.1 %, ES -2.36 ± 0.92) and forwards (-37.5 ± 22.3%, ES -2.21 ± 0.95) and Match 15 for backs (-19.1 ± 37.8%, ES -0.89 ± 1.35) and forwards (-22.0 ± 30.0%, ES -1.10 ± 1.17), and substantial increases during Match 12 in both backs (23.8 ± 37.8%, ES 0.50 ± 0.75) and forwards (14.8 ± 17.2%, ES 0.53 ± 0.61). Accumulated changes in (training stress balance) also found same trends seen in acute weekly changes, where there were substantial decreases during Match 10 and Match 15, and substantial increases during Match 12 in backs and forwards. The results of this study indicate inconsistencies in the changes in [s-IgA] across multi-match analysis, which highlight individual variation in response to the demands of rugby match play. The possible mechanism for the substantial increase in [s-IgA] post rugby match play in Match 10 and Match 12 remains unclear, but it could be attributed to the immune rebounding effect from the physiological disruptions seen in rugby match play. The variation in response to the physiological demands of Super Rugby match play highlight the importance of monitoring players on an individual basis to determine whether rugby union players are able to cope with the demands of rugby match play or are at risk of injury or illness. The present study also found significant increases in [s-IgA] during recovery periods (32 hours post-match play), which suggests the host immunity may not fully restore to its baseline values. The findings of this study also found decreases in weekly training load could potentially have an effect in minimizing the suppression of immune function. As a result, strategic periodization in player loading needs to be considered to reduce the risk of suppression in the immune function and subsequent risk of contracting URTI. The practical application of the present research suggests the importance in combining athlete monitoring methods that include s-IgA and the analysis of player work load to determine the immunological response of elite rugby union players to the physical workloads and demands of Super Rugby.

Date of Award	10 Aug 2016
Original language	English
Supervisor	Christopher P McLellan (Supervisor) & Bon Gray (Supervisor)