Bundesliga: When summer vacation ends at Bayer Leverkusen

There's a lot of sweating going on, on the third floor of the BayArena this July morning as Bayer Leverkusen's players are put through their paces in the club's annual pre-preseason testing.

Kerem Demirbay (pictured above) breathes through a masks as he runs on a treadmill with several cables attached to his body. Karim Bellarabi works on his strength on a fitness machine. Wendell lies on his stomach on the wooden floor straining to flex his back muscles. For Leverkusen's Bundesliga stars, the summer break is now officially over.

"This is the first place the players report to when they return from their vacation," says Malte Krüger, the head of the sports sciences department of the Werkself.

In search of vitamin D

Part of what the sports scientists are looking to find out during the more than three hours of testing is how well the players did in sticking to their individual training plans during their vacation.

"There is a medical element, a physiotherapy element, and one for athletics. We also conduct a body screening," Krüger says. "The aim is to determine the state of the players' health, as well as where their strengths and weaknesses lie."

After the checks have been completed, an individual profile of each player is created, including a large blood count in which parameters such as the level of vitamin D or mineral content are included.

"It has been scientifically proven, for example that a lack of vitamin D increases the risk of injury," Krüger says. With the help of this diagnostic method, it is possible to prevent injury.

Level of oxygen intake

In classical performance diagnostics, which are designed to determine how resilient a player's body is, the aim is to find out in what state of fitness he is and how his body reacts to exertion. The data gathered when a player wearing a breathing mask runs on the treadmill tells the sports scientists how efficient his body is at breaking down carbohydrates and fat. The test also reveals his maximum oxygen intake.

During sprints, not only do the sports scientists find out how fast each player is, but they also analyze their running technique.

"Here, small adjustments can improve their speed," Krüger explains.

Different weighting

But it's not about optimizing the performance of the players in each and every area, even if they are at a high level in all of them.

"It's more about finding the optimum for each player," the sports scientist says. "After all, a goalkeeper requires different physical abilities and strengths than an offensive midfielder."

It's also about discovering muscular imbalances in the body during the strength and mobility tests.

"However, the individual results are weighted differently (according to player)," Krüger explains.

Individual training

"Young players often have some catching up to do in terms of athleticism, while also having to get used to the rhythm. When it comes to older players, who may have been injured before, it's more important to assess what preventive action can be taken to avoid further injuries."

The individual profiles help the coaching staff to respond more precisely to the needs of individual players throughout the entire season. This is done through targeted individual training, which is in addition to regular team training sessions.