2.3. BESS

Before testing, the participants were instructed to execute a ball-kicking task for the determination of their dominant foot. All assessments were conducted without footwear. Six distinct testing positions were evaluated in a specified sequence, encompassing three standing tasks (bipedal with feet hip-width apart, unipedal on the non-dominant foot, and tandem stance with the non-dominant foot positioned at the rear) each lasting 20 s. Each test was executed under two conditions—on both a firm and soft surface (foam pad (48 cm × 40 cm × 6 cm, density: 38.6 kg/m³, AIREX^®, Sins, Switzerland)) with closed eyes. Children were instructed to interrupt testing in the event of discomfort or fatigue. Recorded errors, documented on paper, included hands lifting off the iliac crests, opening of the eyes, taking a step, stumbling, or falling, moving the hip beyond 30 degrees of abduction or flexion, lifting the forefoot or heel, or deviating from the test position for more than 5 s. A predefined maximum of 10 errors was established for each trial, resulting in a maximum possible error count of 60 for the overall BESS score across all six testing positions. All evaluations were conducted by two examiners who had received training in the instrumented BESS testing protocol.