Whilst full team training and matches have resumed at the highest level, grassroots and semi-professional football is still bound by government guidelines. Social distancing poses a unique challenge for players and teams like never before. But amongst the waves of professional footballer Instagram posts and home workout routines that have gone viral over the last few weeks, is it actually possible to maintain and improve match fitness when small- sided games and friendly matches are banned? This mini case study demonstrates some key metabolic considerations, using real match data obtained from a professional player to demonstrate the key talking points.
METABOLIC DEMANDS
The metabolic demands are the demands that are placed on the body's energy systems. When we discuss 'endurance' and 'fitness' in football we need to consider how the game is played. Research has shown that the amount of high intensity actions in modern football has increased significantly in recent years. This is partly due to the increased popularity of counter pressing and counterattacking styles of play, but also partly due to advances in the level of expert sport science support that elite teams and academies have access to. Professional players now spend the vast majority of matches at a heart rate (bpm) above 70% of their maximum and generally expend at least 12-14 calories (Kcal) per minute in matches. This places considerable demands on the bodies energy systems. Below is a typical energy expenditure breakdown from a professional football match. This is real data and represents an example of the typical energy split of what most players I've worked with tend to hit in matches.
As we can see, the overall amount of energy expended was measured to be 1248 Kcal over a full match (equating to roughly 13 calories per minute). This was accomplished with an almost even split between aerobic and anaerobic energy expenditure. This means it is important to train both energy systems accordingly. But what exactly does this metabolic split consist of and how should it be trained?
AEROBIC vs ANAEROBIC TRAINING
To train the aerobic energy systems you have two main options: 1) distance runs and 2) tempo runs. Distance runs are typically 5km or more (you may have seen this from an outrageous Ross Barkley run featured on Instagram recently!). They can be used to train aerobic endurance and can be progressed from session to session by either increasing the distance slightly or completing the same distance in less time. Tempo runs for footballers typically involve a few repetitions and sets of 50-200m efforts running at 60-80% of top speed, with shorter rest periods between repetitions and longer rest periods between sets. They train aerobic power and can be progressed by increasing the tempo of each rep or keeping the same tempo as the last session, or increasing the overall amount of repetitions.
A recent GPS analysis on one of our Club2 workouts showed that the tempo running session allowed the player to hit the same amount of high-speed running as a Premier League match, in just 20 minutes. The session also caused the player to expend energy at a rate of 14.7 calories per minute (slightly higher than the typical match day demands) with an average heart rate of 78% of their max throughout. Due to these high metabolic demands, tempo runs will increase your VO2 max but crucially, they will also increase a player's anaerobic threshold.
Let's take a look at the importance of this now. The image below is an example of what we call a metabolic zone breakdown for a professional player during a match. Note that the following actions typically make up each of the metabolic zones ('Met Zones'). A higher met zone indicates that the bodies energy systems are being stressed to a greater extent.
As we can see, the player is covering more distance in the lower met zones than the higher met zones. Also, the distance in the lower met zones is greater than the relative energy cost. This is because in these met zones the player is using their aerobic energy systems, so the distance is covered fairly easily; expending energy aerobically. When working in the higher met zones, we can see the player is now expending much more energy (Kcal) relative to the distance they are covering. These zones are of a higher metabolic intensity, which causes the player to enter and exceed their anaerobic threshold as they start to expend energy anaerobically. This makes distances covered in these zones much more metabolically demanding, so the energy costs start to outweigh the distance (see graph). Match actions which involve a higher metabolic intensity causes the players heart rate and overall energy cost for that period of play to increase accordingly.
Met zone 5 usually consists of high intensity accelerations rather than anything else. These have by far the greatest energy cost, making them the most metabolically demanding action in football. To emphasise this point, consider this: the acceleration phase of a sprint is on average around 3x as metabolically demanding as the steady speed phase. The record-breaking sprint from last year's Champions League was recorded as 34.5km/h and was performed by Virgil Van Dijk against FC Barcelona. It would take a maximal sprint approaching this kind of record-breaking speed to enter met zone 5. Even then, it would be the high intensity acceleration phase of that sprint that was by far the most demanding part.
IMPROVING MATCH FITNESS
To develop and improve match fitness in the current situation, players must consider the typical energy split of match play, as shown above. Train across all of the met zones and train both the aerobic and anaerobic energy systems accordingly. Aerobic training can consist of a mix of longer distance jogs and tempo runs. Anaerobic training can consist of a mixture of high-speed running, sprints and most demanding of all, high intensity accelerations. The most specific form of training will contain a combination of all met zones and will match the heart rate (bpm) and Kcal/min demands of match play. In the absence of small and large-sided games, interval-based conditioning methods will best replicate the physical demands of the game, where high intensity bursts are interspersed with lower intensity recovery periods.
So, in short, what should you do? Mix your training up, train across each met zone and be specific with your targets for each session that you complete. The end goal is to try to gradually increase the metabolic intensity that you are able to sustain during conditioning sessions, training and ultimately, matches. On the simplest level, this can be achieved and measured by increasing the number of calories expended per minute (Kcal/min) during your sessions. To measure this, use a smart watch, or for optimum accuracy, a chest-based heart rate monitor, to obtain Kcal data from your sessions. Divide the total Kcal figure by the duration of the sessions in minutes, to provide you with a Kcal/min score. As we saw from the case-study above, professional footballers often expend over 13 calories per minute during match play.
Regardless of whether you own a smart watch or heart rate monitor, Club2 provides players with tried and tested conditioning sessions that increase in difficulty over time. All sessions have undergone extensive GPS and Heart Rate analysis, to ensure that they meet the physical demands of both Premier League and elite academy football matches. For players aspiring to play at these or similar levels, it is essential to train accordingly, so that they are physically prepared for the step up.
To conclude, this blog post has focused on improving match fitness from a metabolic perspective. The next one will take a look at improving match fitness and reducing injuries, according to the mechanical demands of match play. In particular, we will look at the importance of deceleration and multi-directional training. We will also discuss the window of opportunity that the current period offers players to get faster and more powerful, as highlighted by Adama Traore in a recent interview.
This article was written by Raj Soni-Tricker, an academy sport scientist at Wolverhampton Wanderers FC.