2019 Research on GPS & Training Load: 5 Key Papers

GPS and training load continue to be a hot topic in sport science with the number of research papers keeping pace with its widespread use in team sports. The major search engine PUBMED identified 111 papers published in 2019 using the key words “GPS and athletes’ – and ‘training load management’ became a household term in America in 2019 thanks to the NBA!

Here’s a summary of 5 key papers published in 2019:

1. Spikes In Acute:Chronic Workload Ratio Associated with a 5-7 Times Greater Injury Rate in English Premier League Football Players: A Comprehensive 3-Year Study. Br J Sports Med. 2019

What’s great about this paper is that it covers 3 full seasons of tracking English Premier League football players from the Southampton Football Club. Most other studies are just 1 season.

The main findings were:

• When chronic load exposure is low, an acute:chronic workload ratio (ACWR) >2.0 is associated with 5–7 times the risk of a soft tissue injury compared to players whose ACWR is <2.0.

• Non-contact injury risk was also 5-6 times higher for accelerations and low-intensity distance when the chronic workloads were categorised as low and the ACWR was >2.0 compared with ACWRs below this.

• Regardless of chronic exposure, a spike in workload is associated with increased injury risk, although this risk is lessened with greater chronic loads.
• A spike in decelerations was associated with the greatest non-contact injury risk.

What does it mean? Coaches and trainers involved in planning training for performance and injury prevention should monitor the ACWR, progressively increase exposure to higher loads, and avoid spikes that approach or exceed 2.0.

2. The Association between the Acute:Chronic Workload Ratio and Injury and its Application in Team Sports: A Systematic Review. Sports Med. 2019

This paper is a systematic review – meaning that the researchers considered all the relevant original research studies (22 single studies in this case) and came up with a general finding. Not only did they look at the relationship between the Acute:Chronic Workload Ratio (ACWR) and injury, but also tried to determine the best mathematical method of the ACWR – comparing the rolling average model and the exponentially weighted moving average model.

The findings of this review support much of the research showing an association between the ACWR and non-contact injuries and its use as a valuable tool for monitoring training load as part of a larger scale multifaceted monitoring system that includes other proven methods.

It was also suggested that ways of calculating the ACWR - rolling average model and the exponentially weighted moving average model - are supported but the exponentially weighted moving average offers greater sensitivity. In addition, the most appropriate acute time period (e.g., 3, 4, or 7 days) and chronic time period (e.g., 21 or 28 days) and training load variables (e.g., total distance, high-speed running) may be dependent on the specific sport and its structure.

3. Comparison of Preseason and In-Season Practice and Game Loads in NCAA Division I Football Players. J Strength Cond Res. 2019

Compared to the other football codes (soccer, rugby, Aussie rules), there is limited research on GPS and American football. However, more and more collegiate and now high school teams are starting to use GPS to track and monitor athlete performance and health.

This study reports on a Power 5 NCAA Division I football team monitored during 22 preseason practices (which were divided into preseason week 1, week 2, and week 3) and across the 12 in-season weeks that included 36 in-season practices and 12 competitions.

It is widely known that the first few weeks of preseason football camp can be grueling. And this study simply put numbers to it.  Weekly training load was significantly higher during preseason than in-season – a training load score of about 3600 during the first 2 weeks of preseason compared to about 1500 in-season. 

What’s the implication?  Given that training load should be progressed to reduce the risk of injury and optimize athlete preparation, it is important to ensure that athletes are accustomed to these loads before the start of the preseason camp and/or the session duration (and intensity) should be gradually increased throughout week 1 (and week 2) of the preseason.

But if you aren’t measuring…. you are only guessing!

4. Elite Male Lacrosse Players' Match Activity Profile J Sports Sci Med. 2019

Lacrosse is one of the fastest growing games in the United States, and SPT is proud to be the official partner of US Lacrosse. The game is also gaining popularity across many parts of the globe with 46 countries competing in the 2018 Men’s World Lacrosse Championship and 25 countries competing in the 2017 Women’s Lacrosse World Cup.

Similar to American football, there is very little research on the movement demands of lacrosse. In this study, the activity profiles of the Japanese national team was quantified using GPS and heart rate during 13 international matches.

Players moved 3800 m at an average speed of 94 m/min with variation by position:

Attackers: 4500m at speed of 81 m/min
Midfielders: 3028m at a speed of 110 m/min
Defenders: 4239m at a speed of 87 m/min

The work:rest ratio was 1:0.64 (i.e., for every minute of work, 0.64 minutes of rest), and here are some of the other key metrics by position.

	Attackers	Midfielders	Defenders
Heart rate (%max)	77	80	85
Walk (m)	2213	839	1820
Jog (m)	1381	1073	1407
Run (m)	789	817	842
Sprint (m)	121	261	169

 

These results can help coaches and performance staff set targets for training and in-season practice plans.

5. High-Intensity Acceleration and Deceleration Demands in Elite Team Sports Competitive Match Play: A Systematic Review and Meta-Analysis of Observational Studies Sports Med. 2019

Often times we look to the common GPS metrics of total distance and high speed running but the physical demands of accelerating and decelerating the body during the dynamic and chaotic nature of team sports can have a significant impact on muscle fatigue, muscle damage, risk of injury and performance. More specifically, accelerations have a high metabolic cost and decelerations cause high mechanical forces on the muscles and joints.

This paper is another systematic review but also quantifies all the studies using a summary statistic (meta-analysis). A total of 19 studies representing a total of 469 elite male athletes from 7 different team sports were included.

Only high intensity (> 2.5 m·s⁻²) and very high intensity (> 3.5 m·s⁻²) acceleration and deceleration were considered.

The key points gleaned were:

• All team sports (Australian Football, field hockey, rugby codes, and soccer) except American Football reported a greater frequency of decelerations compared to accelerations.
• There was a small decrease in the frequency of high and very high intensity accelerations and decelerations from the first to the second half periods of elite competitive match play, suggesting intense accelerations and decelerations could be particularly vulnerable to fatigue and risk of injury.
• To ensure that athletes are optimally prepared for the high-intensity accelerations and decelerations of competitive play, it is imperative that athletes are exposed to comparable demands under controlled training conditions.

These are only 5 of the 111 papers published on GPS and training load monitoring in athletes from 2019. We look forward to sharing more research and best practices in sport science in 2020.

Click here to contact SPT's Sport Science team with any enquiries.