SSA Blog: VAR and the physicality of football

Last week saw the introduction, into competitive English football, on a trial basis, of the video assistant referee technology system (VAR). It follows last season’s successful implementation of goal line technology and is the latest in a growing number of virtual, tracking or predictive technologies introduced to support officials and referees across sport.

Arguments as to the benefits and drawbacks have been well reported. What has gained less coverage is the potential impact regarding players’ physical load during a game.


Throughout sport, rule changes and the introduction of technology have affected how the game is played and the nature of the players playing it. Tennis is a prime example.  Players often use the challenge system tactically, in an attempt to break opponents’ momentum or gain extra recovery time following a high-intensity rally.

Football at the highest level requires players to combine a number of fitness elements. It involves high intensity sprinting, accelerations, strength, an endurance base as well as the application of skill and mental agility to deal with tactical demands.

In the English Premier League, the average 90 minute game sees the ball in play for 56.17 minutes. Players are covering distances of nearly 11km per game of which over 10% is covered at high speed. But the biggest increase in activity levels has come in the number of high intensity runs players now make. Data from Barnes et al, back in 2014, showed that players were making 49% more high speed runs than in 2007 and the total distance and intensity numbers are expected to have continued to rise.

The game is undoubtedly speeding up though many have argued VAR may slow it down. What they actually mean is, VAR will impact the ball in play time. But can VAR actually increase ball in play time? Or could it lead to changes in player load and even greater physical demands?

A recent study examining the evolutionary changes in activity and recovery in Rugby League, published by Gabbett & Hulin (2017) in the Journal of Sport Sciences, showed the greatest impact on ‘ball in play’ time resulted from video referee stoppages. It also showed that ‘in game recovery’ time actually increased. So, while video referee referrals reduced the ‘ball in play’ time, it also produced greater recovery time for players, which can enable greater player load/exertion levels to be reached during games.

Could the same be a consequence of the introduction of VAR in football?

There are two areas to consider here:

  1. Will VAR reduce ball in play time?
  2. Will VAR effect in game recovery (and therefore training practices to address this)?

Until the system has been fully trialled and evaluated it is difficult to answer either of these questions. However anecdotal evidence from goal line technology points to more ball in play time as players no longer challenge the referee during breaks. This leads to play being resumed without incident. Evidence from Rugby League and Rugby union on the other hand, suggests that ball in play time has been reduced by the introduction of video technology as game time is lost during those time on and time off moments during referrals.

The really interesting analysis will be the impact, if any, on the players physical demands. Will, as we have seen in Rugby League, increased in game recovery time allow players to compete at even higher intensities once play resumes? Will more effective decision making mean less stoppages and a reduction of in game recovery? And what impact will this have regarding player preparation in order to cope with the potential physical challenges VAR might bring.  

It’s too early to know how VAR will impact player load and the physical demands of the Premier League.  As the system’s adoption increases, sport science teams will evaluate how its introduction impacts areas such as ball in play and in game recovery. If it does, as in both codes of Rugby, start to alter the physical demands of the game, the challenge for clubs will be to adapt training, ensuring players are prepared for these new demands. 

Sport Science Agency works with brands, broadcasters, rights holders and agencies to create insight, experiences and content from the latest sport science research. If you want to know more just drop us a note via and we can arrange to go for a healthy performance boosting drink.