Olive Leaf Extract in Handball Players

Karabuk University18 enrolled

Overview

Olive leaf extract (OLE) is a natural supplement rich in phenolic compounds, especially oleuropein, which has antioxidant properties that may support recovery after physical exercise. While OLE has been studied for various health-related effects, its potential impact on exercise recovery and performance in elite athletes remains unclear. This randomized, double-blind, placebo-controlled study was designed to evaluate the effects of four weeks of OLE supplementation on physical performance, sleep quality, and post-exercise muscle soreness in elite male handball players aged 18 to 25 years. Participants were randomly assigned to receive either a daily OLE supplement (500 mg, standardized to 25% oleuropein) or a placebo for four weeks. Physical performance, sleep quality, and muscle soreness were assessed at baseline, during the intervention, and at the end of the study period. Muscle soreness was additionally evaluated at 12 and 24 hours following exercise sessions.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

PREVENTION

Masking

TRIPLE

Enrollment

Conditions

Handball Players

Interventions

Eligibility

Sex: MALEMin age: 18 YearsMax age: 25 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Male elite handball players aged 18 years or older * Free from any diagnosed chronic disease, as determined by medical history * Not following a calorie-restricted diet within the previous six months * No use of nutritional supplements within the previous six months Exclusion Criteria: * Age under 18 years * Smoking or alcohol consumption * Presence of any diagnosed chronic disease * Adherence to a regular calorie-restricted diet within the previous six months * Use of nutritional supplements during the previous six months

Outcomes

Primary Outcomes

Muscle Soreness

The severity of muscle soreness will be assessed using the Visual Analog Scale (VAS). Patients choose the appropriate score between 0 and 10. Higher scores indicate higher muscle soreness levels.

Time frame: Baseline, After intervention (two week later), After intervention (fourt week later)

Squat jump height

Lower-body explosive performance was assessed using the squat jump test. Jump height was measured in centimeters (cm) with higher values indicating better explosive performance.

Time frame: Performance outcomes were assessed at baseline, week 2, and week 4 of the intervention period.

Peak anaerobic power

Peak anaerobic power was assessed using the Wingate anaerobic test. Peak power output was recorded in watts (W) during the 30-second maximal cycling test. Higher values indicate greater anaerobic power.

Time frame: baseline, week 2, and week 4.

Countermovement jump height

Lower-body explosive performance was assessed using the countermovement jump test. Jump height was measured in centimeters (cm) with higher values indicating better explosive performance.

Time frame: Assessments were conducted at baseline, week 2, and week 4. Higher values indicate better explosive performance.

Mean anaerobic power

Mean anaerobic power was assessed using the Wingate anaerobic test. Mean power output was calculated as the average power produced over the 30-second test and recorded in watts (W). Higher values indicate better anaerobic capacity.

Time frame: Baseline, week 2, and week 4

Fatigue index

Fatigue index was assessed using the Wingate anaerobic test and calculated as the percentage decline in power output from peak to minimum power during the 30-second test. Higher values indicate greater fatigue.

Time frame: Baseline, week 2, and week 4

Secondary Outcomes

Sleep quality

Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI) total score. The PSQI is a validated self-reported questionnaire consisting of 19 items, yielding a global score ranging from 0 to 21, with higher scores indicating poorer sleep quality.

Time frame: Total PSQI scores were recorded at baseline, week 2, and week 4 to evaluate changes in perceived sleep quality during the supplementation period.