Inclusion Criteria:

• Age between 18 and 26 years
• Active student or doctoral student status at a higher education institution
• Active participation in sports training (endurance or mixed disciplines, e.g., cycling, running, triathlon, team sports) with a minimum frequency of 3 times per week, verified by a recruitment questionnaire.
• Good general health, with no medical contraindications to performing intense exercise testing on a cycle ergometer.
• Normal anatomical condition of the Achilles tendon and patellar ligament during baseline screening - no history of acute inflammation or ruptures.
• Provision of voluntary, written informed consent to participate in the study and for medical data processing.

Exclusion Criteria:

• Orthopedic and structural contraindications: Recent injuries in less than 6 months, joint ruptures, or surgical interventions in the lower limbs; chronic or acute inflammation of the Achilles tendon or patellar ligament; presence of metal implants or joint replacements in the stimulated limbs.
• Neurological contraindications: Diagnosed epilepsy or susceptibility to seizures, superficial or deep sensory impairment such as neuropathy, radiculopathy, that could impair stimulus evaluation or risk tissue damage.
• Cardiovascular contraindications: Diagnosed heart defects, unstable arterial hypertension, cardiac arrhythmias; presence of a pacemaker or implantable cardioverter-defibrillator, active thromboembolic diseases, deep vein thrombosis, or severe varicose veins of the lower limbs.
• General medical contraindications: Pregnancy; active oncological diseases; active infections or fever on the day of testing; dermatological changes, open wounds, or skin ulcers at the planned application sites of sEMG electrodes or Tendo vibration sleeves.
• Other: Regular intake of medications or substances that affect the threshold of pain or fatigue perception (e.g., strong analgesics, steroids, or pre-workout supplements containing high amounts of stimulants taken directly before the test).