A joint is considered "hypermobile" when it has a greater range of motion than normal for a given age, ethnicity or gender. Many people have asymptomatic hyperlaxity in multiple joints, a condition called Generalized Joint Hypermobility (GJH).

Conversely, hyperlaxity can be symptomatic, a condition that has been defined "Joint Hypermobility Syndrome" - JHS.

Diagnosis of JHS is commonly performed by applying the revised Brighton criteria. Based on these criteria, an individual is diagnosed with JHS with a Beighton score >/= 4/9, and arthralgia for 3 or more months in 4 or more joints (major criteria).

The dynamic body balance test (i.e. the stability test with multiple single-leg jumps) can provide information regarding the effectiveness of the feedforward and feedback mechanisms in correcting the postural deviations necessary to achieve successful performance during daily and sporting activities. Such assessment may also be useful to demonstrate deficiencies in balance, especially in young patients with increased physical activity.

The aim of this study is to examine the postural balance of individuals with JHS by performing stability tests in monopodalic and bipodalic stance with the "Delos Postural Proprioceptive System"

Inclusion Criteria:

• Patients with moderate (Beighton-Horan Joint Mobility Index score from 3 to 4) or severe (Beighton-Horan Joint Mobility Index score from 5 to 9) joints hyperlaxity at the clinical evaluation

Exclusion Criteria:

• Obesity (BMI > 25) and weight > 90 kg
• Practice of competitive sport
• Orthopedic (complex surgery of the spine and lower limbs), neurological (spasticity, stroke), and oncological comorbidities
• Orthostatic / walking inability
• Absence of joints hyperlaxity at the clinical evaluation (Beighton-Horan Joint Mobility Index score from 0 to 2)

Patients with moderate (Beighton-Horan Joint Mobility Index score from 3 to 4) or severe (Beighton-Horan Joint Mobility Index score from 5 to 9) joints hyperlaxity at the clinical evaluation