The Real Home-Field Advantage Vol. 1

Yannick Lambrichts

11 Mar 2022

Ready to step out on the field, deafening roars of the crowd and the stadium anthem blasting through the speakers. These are psychological motivational techniques that certainly motivate and help the home team. But if you want to fully exploit the home advantage, you have to consider the surface. The ground you run on, impacts your performance and influences injury risks.

Every detail gets analysed and prepared from team formation to AI modelling, to optimising training load throughout the week. A big contribution to team performance and its success, is the quality of the playing surface. How are performance and grounds staff ensuring the perfect pitch?

Vertical impact/energy
Test the mechanical properties of the surface that affect performance.
Running shoes are selected based on the optimal balance between stiffness for speed and shock absorption for comfort and safety. As football boots hardly modify the impact, surfaces need to have optimal mechanical properties to ensure speed and safety. Football pitches are tested on multiple parameters. Elasticity is tested and related to energy expenditure of players. The lower the energy restitution, the sooner players will fatigue and are likely to underperform.

The timing of energy return is crucial to enable players to use it. Leg stiffness can be marginally modified so the retrieved energy is optimally used. However, if the spring rate (speed of E return) lies outside of the muscle’s capabilities, energy return is lost (too late) or returned as a shock (too fast).

Shock absorption of the surface relates to the impact on the athlete’s tendons, joints and muscle’s structural elements which affects acute and chronic injuries. However, firm surfaces can help players achieve high speeds more easily when compared to very compliant ones. Football pitches tend to deform slightly with every impact. Some of the deformation is permanent, while a part is restored. This surface deformation affects players comfort and stability as the top layer of the pitch functions as a visco-elastic cushion.

Horizontal forces
Players are constantly changing directions with different intensities. Pitches should provide players sufficient traction and rotational resistance to accelerate, brake, thrust and turn efficiently. With insufficient resistance by the plant and soil, the surface gives away inhibiting players to perform powerful agile movements. Surface traction is provided by the interplay between root strength, soil moisture and soil particle size and shape. Players usually choose their boots based on the perceived amount of available traction but can now base their decision on objective data. Shoe-surface traction can be increased or decreased with about 20% by choosing a different outsole. Under hazardous torque the surface should give way. If not, torsion is transferred up the body and puts joints and ligaments at risk.

Some surfaces have a very compacted top layer, making it hard for studs to penetrate the soil. This is needed for the players to use the available traction. When studs do not penetrate the soil and force is applied, slipping is imminent. The amount of force needed for studs to penetrate the soil is called Stud force and can be objectively measured (with the Raw Traction Tester).

Ground staff can use this and all above mentioned measurements and data to optimally prepare the training and stadium pitches, tailored to the needs and safety of their players.