Original research
High chronic training loads and exposure to bouts of maximal velocity running reduce injury risk in elite Gaelic football

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Abstract

Objectives

To examine the relationship between chronic training loads, number of exposures to maximal velocity, the distance covered at maximal velocity, percentage of maximal velocity in training and match-play and subsequent injury risk in elite Gaelic footballers.

Design

Prospective cohort design.

Methods

Thirty-seven elite Gaelic footballers from one elite squad were involved in a one-season study. Training and game loads (session-RPE multiplied by duration in min) were recorded in conjunction with external match and training loads (using global positioning system technology) to measure the distance covered at maximal velocity, relative maximal velocity and the number of player exposures to maximal velocity across weekly periods during the season. Lower limb injuries were also recorded. Training load and GPS data were modelled against injury data using logistic regression. Odds ratios (OR) were calculated based on chronic training load status, relative maximal velocity and number of exposures to maximal velocity with these reported against the lowest reference group for these variables.

Results

Players who produced over 95% maximal velocity on at least one occasion within training environments had lower risk of injury compared to the reference group of 85% maximal velocity on at least one occasion (OR: 0.12, p = 0.001). Higher chronic training loads (≥4750 AU) allowed players to tolerate increased distances (between 90 to 120 m) and exposures to maximal velocity (between 10 to 15 exposures), with these exposures having a protective effect compared to lower exposures (OR: 0.22 p = 0.026) and distance (OR = 0.23, p = 0.055).

Conclusions

Players who had higher chronic training loads (≥4750 AU) tolerated increased distances and exposures to maximal velocity when compared to players exposed to low chronic training loads (≤4750 AU). Under- and over-exposure of players to maximal velocity events (represented by a U-shaped curve) increased the risk of injury.

Introduction

Training load has been reported as a modifiable risk factor for subsequent injury.1 Several studies have investigated the influence of training workload and injury risk in team sports. In professional rugby union, players1 higher 1-week (>1245 AU) and 4-week cumulative loads (>8651 AU) were associated with a greater risk of injury. Furthermore, Rogalski et al.2 observed that larger 1-weekly (>1750 arbitrary units, OR = 2.44–3.38), 2-weekly (>4000 arbitrary units, OR = 4.74) and previous to current week changes in load (>1250 arbitrary units, OR = 2.58) were significantly related to greater injury risk throughout the in-season phase in elite Australian rules football players.

The ability to produce high speeds is considered an important quality for performance, with athletes shown to achieve 85–94% of maximal velocity during team sport match-play.3 Well-developed high-speed running ability and maximal velocity are required of players during competition in order to beat opposition players to possession and gain an advantage in attacking and defensive situations.4, 5 In order to optimally prepare players for these maximal velocity and high speed elements of match play, players require regular exposure to periods of high-speed running during training environments6. Recent evidence suggests that lower limb injuries are associated with excessive high-speed running exposure.7, 8 Within elite rugby league and Australian football cohorts, players who performed greater amounts of very high-speed running within training sessions were 2.7 and 3.7 times more likely to sustain a non-contact, soft tissue injury than players who performed less very-high speed running.8, 9 However, these studies failed to assess the potential impact that chronic training load could have on reducing the injury risk in these players. Currently there is a lack of understanding of the potential benefits of maximal velocity exposures and also the minimum dose required to provide protection against injuries.

Recent evidence suggests that high chronic training loads can offer a protective stimulus for team sport athletes.10, 11 Australian rules football players with higher 1 week training loads (>3519 AU) were at reduced risk of injury (OR = 0.199) compared to players exposed to lower training loads (<3518 AU).12 Additionally Cross et al.1 have reported a U-shaped curve for training load and injury risk in elite rugby union players with low and high training loads increasing injury risk, and intermediate loads reducing injury risk. High aerobic fitness has been reported to offer a protective effect against subsequent lower limb injury for team sport players.6 Higher training loads may be needed to provide the appropriate stimulus for aerobic fitness improvements6 with lower training loads potentially placing players at increased risk due to a lack of exposure to the physical stimulus required for competitive play.6

Although greater amounts of high-speed running have been associated with injury risk, there is evidence that players are often required to perform maximal efforts over short to moderate distances during competition and training.13, 14, 15 Training for team sport ultimately requires a balance between appropriately prescribed training loads to develop the required physical qualities to compete while also allowing the appropriate recovery between sessions and match-play to minimise injury risk for players. Given the need for players to perform maximal efforts during match-play, exposure of players to these maximal efforts during training may offer a “vaccine” against soft-tissue injury.6 However, the inter-relationship among these training variables and potential injury risk is poorly understood. Therefore the aim of the current investigation was to examine exposure to maximal velocity events as a potential modifiable risk factor for injury within Gaelic football. Additionally with higher chronic training loads offering a protective effect from injury in other sports, there is a need to investigate the interaction of chronic training loads, maximal velocity exposure, and injury risk within Gaelic football. Accordingly, we explored the relationship between training load, the number of maximal velocity exposures during training and match-play, the distance covered at maximal velocity and injury risk in elite Gaelic football players.

Section snippets

Methods

The current investigation was a prospective cohort study of elite Gaelic football players competing at the highest level of competition in Gaelic football (National League Division 1 and All-Ireland Championship). Data were collected for 37 players (Mean ± SD, age: 24 ± 3 years; height: 179 ± 5 cm; mass: 79 ± 7 kg) over one season. The study was approved by the local institute’s research ethics committee and written informed consent was obtained from each participant.

The intensity of all competitive

Results

In total, 91 time-loss injuries were reported across the season (36 training injuries and 55 match injuries). A rate of 2.4 injuries per player was observed. Overall, match injury incidence was 45.3/1000 h (95% CI: 41.9–53.8) with a training injury incidence of 6.9/1000 h (95% CI: 5.8–7.8). The total match and training volumes reported during the season were 1210 h and 5975 h respectively.

Players who produced over 95% maximal velocity within training and match-play environments in the preceding

Discussion

The current investigation is the first to explore the relationship between training load, maximal velocity exposures and injury risk in elite Gaelic football players. Our data showed that when players’ produced over 95% of their maximal velocity they were at reduced risk of subsequent injury (OR: 0.12) (Table 1). When maximal velocity exposures were considered independently of training load history a U-shaped curve was shown for number of exposures and subsequent injury risk (Supplementary Fig.

Conclusion

In conclusion when maximal velocity exposures were considered independently of training load history a U-shaped curve was shown for number of exposures and subsequent injury risk. Our data suggests that players who produce ≥95% of their maximal velocity were at reduced injury risk compared to players who produced lower relative maximal velocities. Coaches should expose players to high percentages of maximal velocity within training situations as this offers a potential “vaccine” against

Practical applications

  • Exposure of players to maximal velocity running should be mainstream practice in elite sport in order to adequately prepare players for maximal velocity situations during match-play.

  • Coaches should allow for situations within training where players can achieve high percentages of maximal velocity as these situations offer a potential protective effect against injury.

  • Players who produce ≥95% of their maximal velocity are at reduced injury risk compared to players who produced lower relative

Acknowledgements

The authors would like to acknowledge with considerable gratitude the players, coaches and medical staff for their help throughout the study period.

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