The kBox targets many important aspects of developing a Tennis player’s strength and is already adopted by high-level players.

With flywheel training on the kBox tennis players have a tool for improving sprint speed, change of direction ability and hitting power.


In Tennis, the kBox is a tool for training many aspects of the player’s physique. It’s used for lower limb work to improve starting strength and speed in change of direction, by way of squats, split squats and lateral squats for example. Overloaded actions targeting the end range eccentric strength are excellent both for acceleration and overall speed. Upper body and core drills are important both for performance and hitting power but also to improve shoulder health through various drills such as rotations, rows and pulls that may involve hip movement.


Studies have shown change of direction performance has been strongly linked to eccentric strength in a study involving elite female basketball athletes (Spiteri et al 2014) and studies using flywheels have shown acute and chronic adaptations to flywheel training that improved both linear and acceleration speed and change of direction performance (Hoyo et al 2015, Hoyo et al 2016).

The Exxentric Harness reduces a lot of the torque and stress on the lower back which makes the training very efficient, accessible and safe for athletes without a specific gym background. Using the kMeter makes it easy and safe to perform and monitor your athletes.

Go back to applications for sports performance.


kBox4 Active

Our entry level model for the serious personal trainer or demanding home user. The perfect tool in strength and rehabilitation at our lowest price point.

  • Entry Level Model
  • Holds 1-2 Flywheels
  • kMeter Compatible
  • Weighs 15 kg
  • Starting at €1 410 / $1 635
Shop System

kBox4 Lite

Offers the lowest weight and best portability which makes it perfect for frequent travel without compromising the training.

  • Enhanced Portability
  • Holds 1-4 Flywheels
  • Built in kMeter
  • Weighs 9.5 kg
  • Starting at €2 300 / $2 665
Shop System

kBox4 Pro

Our premium kBox model with the greatest versatility and largest performance area. It’s ideal for sports teams, premium fitness clubs and physiotherapy facilities.

  • Largest Performance Area
  • Holds 1-4 Flywheels
  • Built in kMeter
  • Weighs 15.5 kg
  • Starting at €2 990 / $3 465
Shop System


The kPulley2 is the ideal horizontal solution for improving strength by offering flywheel training for rotational and pull exercises.

  • Horizontal Model
  • Holds 1-2 Flywheels
  • Built in kMeter
  • Easy to assemble
  • Starting at €1 890 / $2 190
Shop System