All participants underwent the same protocol: two laboratory assessments, a 106 km race, and post-race physiological parameter evaluations at 24 hours and 48 hours.

All participants underwent the same protocol: two laboratory assessments, a 106 km race, and post-race physiological parameter evaluations at 24 hours and 48 hours.

Blood Analysis: Blood samples will be analyzed for the following parameters:

• Number of red cells in a volume of blood in µL. (number of red cells x10^6 / µL )
• Creatine Kinase (CK) in International Units in a volume of blood in litres. (U/L)
• Lactate Dehydrogenase (LDH) in International Units in a volume of blood in litres. (U/L)
• C-reactive Protein (CRP) in milligrams in a volume of blood in litres. (mg/L)
• Sodium (Na) in millimoles in a volume of blood in litres (mmol/L)
• Potassium (K) in millimoles in a volume of blood in litres (mmol/L)
• Interleukin 6 (IL-6) in picograms in a volume of blood (pg/dL)

Blood Sample Collection: Blood samples will be collected twice during the second laboratory session-once before starting the treadmill test (negative 15% incline for 5 km at VT1 speed) and again 30 minutes after completing the test. Additional blood samples will be taken at baseline before the race, at the finish line, 24 hours post-race, and 48 hours post-race.

The knee extensors will be measured using ultrasound. Muscle fibre thickness of Rectus femoris and Vastus lateralis will be measured in cm.

Pennation angle of muscle fibre of Rectus femoris and Vastus lateralis will be measured in degrees.

The ankle extensors will be measured using ultrasound. Muscle fibre thickness of Medial gastrocnemius will be measured in cm. Pennation angle of muscle fibre of Medial gastrocnemius will be measured in degrees.

Assessments will be conducted twice during the second laboratory session: once before starting the treadmill test (-15% incline for 5 km at VT1 speed) and again 30 minutes after completing the test. Additionally, measurements will be taken at baseline before the race start and at the finish line

Measurements:

• Squat Jump (SJ): Jump height in centimetres will be measured during a vertical jump performed from a squat position without a countermovement.
• Reactive Strength Index (RSI): The subject performs a sequence of 10 consecutive jumps, during which flight time (in milliseconds) and ground contact time (in milliseconds) are measured. These two variables are used to calculate the Reactive Strength Index (RSI), defined as the ratio of flight time to contact time (flight time in milliseconds / contact time in milliseconds).
• Maximal Isometric Strength (MIS): The isometric strength of the knee and ankle extensors will be measured in Newtons (N).

Collection of Measurements: • Squat Jump will be evaluated during the first laboratory session (first week), before and after cardiopulmonary test (two jumps per attempt). • Reactive Jump will be assessed during the first laboratory session (first week), before and after the 5 km at VT1 speed treadmill test (-15% incline)

Weight in kilograms, height in meters. Weight and height will be combined to report BMI in kg/m^2.

Assessed using bioelectrical impedance analysis (BIA) to estimate percentage of fat mass (%), percentage of fat-free mass (%), and total body water (L). The percentage of fat mass (%), percentage of fat-free mass (%), and total body water (L) will be used to know the body composition of the subject combining the percentage of fat mass, percentage of fat free mass and total body water.

Collection of Measurements:

• Weight, height, BMI, percentage of fat mass, percentage of fat-free mass, total body water and Body composition will be measured during the first laboratory assessment (1st week)