In this observational study embedded within a randomized controlled trial, the investigators aim to characterize the activation patterns of the tibialis anterior and medial gastrocnemius muscles in the more rigid leg of patients with Parkinson's disease when performing walking tasks under dual cognitive-task conditions, which are known to increase the risk of falls in this population.

To this end, a control group without neurological disorders and with comparable sociodemographic characteristics will also be assessed.

The study seeks to determine whether significant changes occur in forward and backward gait as a function of the dual-task condition.

Inclusion Criteria:

• Ability to walk independently for at least 5 meters, both forward and backward, without the need for assistive devices or assistance from another person.
• Diagnosis of idiopathic Parkinson's disease made by a neurologist at Hospital Virgen Macarena.
• Hoehn and Yahr stage I-III.
• Being in the "ON" phase of antiparkinsonian medication during the assessment (approximately one hour after intake, when the pharmacokinetic curve of levodopa reaches its peak).

Exclusion Criteria:

• Presence of symptomatic musculoskeletal disorders affecting the lower limbs (LL) (relevant orthopedic surgery or leg length discrepancy > 1 cm), or other neurological conditions (stroke, neuropathies, etc.) that independently affect gait.
• Balance disorders due to other causes (vestibulopathy, severe orthostatic hypotension, etc.).
• Decompensated systemic diseases (cardiac disease, COPD, uncontrolled diabetes mellitus, etc.).
• Uncorrected visual impairments that may affect gait performance.
• Previous treatment with deep brain stimulation.

Patients with Parkinson's disease and mild cognitive and gait functional impairment recruited from the Parkinson's Association of Seville.