Handball Players
Conditions
Brief summary
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.
Interventions
DIETARY_SUPPLEMENTOlive leaf extract
OLE supplement (500 mg, standardized to 25% oleuropein)
OTHERPlacebo
Sucrose capsules with the same color, scent, and size as OLE capsules.
Sponsors
Karabuk University
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
TRIPLE (Subject, Caregiver, Investigator)
Masking description
double blind (participant investigator)
Intervention model description
Parallel assigned
Eligibility
Sex/Gender
MALE
Age
18 Years to 25 Years
Healthy volunteers
No
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Muscle Soreness | Baseline, After intervention (two week later), After intervention (fourt week later) | 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. |
| Squat jump height | Performance outcomes were assessed at baseline, week 2, and week 4 of the intervention period. | 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. |
| Peak anaerobic power | baseline, week 2, and week 4. | 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. |
| Countermovement jump height | Assessments were conducted at baseline, week 2, and week 4. Higher values indicate better explosive performance. | 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. |
| Mean anaerobic power | Baseline, week 2, and week 4 | 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. |
| Fatigue index | Baseline, week 2, and week 4 | 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. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Sleep quality | Total PSQI scores were recorded at baseline, week 2, and week 4 to evaluate changes in perceived sleep quality during the supplementation period. | 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. |
Countries
Turkey (Türkiye)
Outcome results
None listed