Written by: Hembre, A.1 and Eriksrud, O.2

1 Apex klinikken, Oslo, Norway
2 1080 Motion AB, Stockholm, Sweden


In soccer, muscle injuries account for 25-31% of all injuries (Ueblacker, Muller-Wohlfahrt & Ekstrand, 2015;
Ekstrand, Hagglund & Walden, 2011). Muscle injuries of the lower extremities dominate (92%), with injuries to
the major muscle groups as follows: hamstrings (38%), adductors (23%), quadriceps (21%) and calf (13%)
(Ekstrand et al, 2011). Soccer appears to be a sport particularly susceptible to quadriceps strains, considering
that among collegiate sports, soccer has the highest reported rate of such injuries (Eckard, Kerr, Padua, Djoko,
& Dompier, 2017).

Effective return-to-play strategies in professional sports not only save money, but also improve performance
since the chance of reinjury and time away from competition is decreased. Thus, the decision to return to play
made by the coach, trainer and healthcare professional is very important.

Data can aid this decision, especially if data from multiple sources are in agreement. An assessment of both
structure (ultrasound) and mechanical output (force, speed or power) can provide valuable information.
Ultrasound is used in the assessment of quadriceps strains (Ibounig & Simons, 2016), while lower extremity
mechanical output is commonly assessed in isolated joint movements (e.g., isokinetics) (Fousekis, Tsepis,
Poulmedis, Athanasopoulos, & Vagenas, 2011).

Considering that kicking is an important multi-joint movement of soccer, and that an explosive contraction of
the quadriceps creates a risk of quadriceps strains, it is interesting to observe that such movements are not
assessed. With the development of robotic technology such as the 1080 Quantum, movements specific to a
given task can easily be simulated with documentation of mechanical output. A simulated soccer kick can be
performed in such a system, providing coaches, trainers and clinicians valuable information of mechanical
output (force, speed and power).

The purpose of this case study was to show how mechanical output of a simulated soccer kick in a professional
soccer player supported by structural assessment (ultrasound) can be used in return-to-play decisions.