Isokinetic Knee Strength, Bilateral Muscle Balance, and Anaerobic Performance in Adolescent Athletes
Isokinetic Knee Strength · Hamsting-to-Quadriceps Strength Ratio · Anaerobic Performance
What this study involves
The registry does not currently label this study as recruiting. Ask about its status before planning a screening visit.
- Study type
- Observational
- Phase
- Not applicable / not listed
- Age range
- 15 years - 16 years
- Sex eligible
- Male
- Healthy volunteers
- Accepted
- Participants
- 21 Estimated
These are starting points, not an eligibility decision. The research team must review the full requirements.
About the research
This study looks at how strong the knee muscles are in adolescent athletes and how this strength relates to short-term, high-intensity (anaerobic) performance. Strong, well-balanced thigh muscles may help athletes produce more power during sport movements, but this has not been studied well in teenagers. Male athletes aged 15-16 years will be measured on two separate days. On the first day, their height and body weight will be measured and the strength of the muscles at the front (quadriceps) and back (hamstrings) of both thighs will be tested on a special strength-testing machine. On the second day, they will do a 30-second all-out cycling test to measure anaerobic power. The study will compare the right and left legs and will examine whether knee muscle strength and the balance between the front and back thigh muscles are linked to power output during the cycling test. No treatment or intervention will be given. The results may help coaches and sports scientists understand the physical development of adolescent athletes.
Read the full description
Lower-limb strength and anaerobic power are important parts of the physical profile of adolescent athletes in high-intensity sports such as wrestling. Isokinetic dynamometry allows knee extensor (quadriceps) and flexor (hamstring) strength and the balance between these muscle groups to be measured objectively, while the 30-second Wingate Anaerobic Test (WAnT) is a widely used laboratory test of anaerobic performance. Evidence on how these measures relate to each other in adolescent athletes is limited.
This is a cross-sectional, correlational observational study. Twenty-one male adolescent athletes aged 15-16 years will be recruited in Malatya, Turkey. Written informed consent will be obtained from parents or legal guardians, and assent from participants. Testing will take place on two separate days to limit fatigue. Participants will avoid heavy exercise for 48 hours and caffeine for 12 hours before testing.
Day 1: Height and body mass are measured and body mass index is calculated. Concentric knee extension and flexion are then tested bilaterally on a HUMAC NORM isokinetic dynamometer at 60, 120 and 180 degrees per second (three practice repetitions followed by five maximal repetitions at each speed; 45 seconds of rest between speeds and 10 minutes between limbs). Peak torque is recorded for the quadriceps and hamstrings of each limb, and the conventional hamstring-to-quadriceps (H/Q) ratio is calculated.
Day 2: Participants complete a 30-second WAnT on a mechanically braked cycle ergometer (Monark 874E) with a braking load of 0.075 kg per kg of body mass, after a standardized warm-up. Peak power, mean power and fatigue index are recorded.
Differences between the right and left limbs will be examined with paired-samples t-tests (with 95% confidence intervals and Cohen's dz). Associations between isokinetic variables and WAnT outcomes will be examined with Pearson correlation. The sample size (minimum 19) was calculated with G\*Power for a correlation of r = 0.60 (alpha = 0.05, power = 0.80); 21 participants are planned to allow for possible data loss.
Who may be able to participate?
The list below is the sponsor’s full registry wording. It can include conditions, prior treatment, test results and other requirements. A match in search does not mean you qualify.
Inclusion Criteria:
- Actively practicing wrestling in Malatya, Turkey
- Male, aged 15-16 years
- At least 2 years of regular training (at least 2 days per week)
- No lower-extremity injury or surgery in the last 6 months
- No musculoskeletal, cardiometabolic, or neurological condition that could prevent testing
- Willing to participate in all planned tests
- Written informed consent signed by parent or legal guardian, and assent from the participant
Exclusion Criteria: \* Younger than 15 or older than 16 years
- Lower-extremity injury or surgery within the last 6 months
- Musculoskeletal, cardiometabolic, or neurological condition that could prevent testing
- Open wound, varicose veins, acute inflammation, or history of thrombosis
- Regular use of analgesic or anti-inflammatory medication or ergogenic supplements in the last 3 months
- Unable to attend all planned testing sessions
- Unwilling to follow the pre-test rules (no heavy exercise for 48 hours, no caffeine for 12 hours, usual training and diet)
- Withdrawal during the study due to non-compliance, incomplete sessions, serious injury or illness, or participant request
Study population
Male adolescent athletes aged 15-16 years who actively wrestle and train regularly in Malatya, Turkey. Participants are healthy athletes recruited from local clubs on a voluntary basis.
Understand screeningTreatment, groups and participation
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- Assignment
- Not reported
- Masking
- Not reported
Adolescent Athletes
Male adolescent athletes aged 15-16 years who regularly train and compete. All participants complete anthropometric measurements, bilateral isokinetic knee strength testing, and the Wingate Anaerobic Test on separate days.
Diagnostic Test: Isokinetic Knee Strength Testing · Diagnostic Test: Wingate Anaerobic Test
Isokinetic Knee Strength Testing DIAGNOSTIC_TEST
Bilateral concentric knee extension and flexion tested on an isokinetic dynamometer at 60, 120, and 180 degrees per second. Peak torque and the conventional hamstring-to-quadriceps ratio are recorded.
Wingate Anaerobic Test DIAGNOSTIC_TEST
A 30-second all-out cycling test on a mechanically braked cycle ergometer with a braking load of 0.075 kg per kg of body mass. Peak power, mean power, and fatigue index are recorded.
What researchers are measuring
Outcome measures describe what is being studied. They are not proof that a treatment works.
Primary measures
Isokinetic Peak Torque of the Knee Extensors and Flexors
Time frame: Day 1 of testing (single measurement session)
Peak torque (N·m) of the quadriceps and hamstrings, measured separately for the right and left limbs at 60, 120, and 180 degrees per second on an isokinetic dynamometer (highest value across five maximal concentric repetitions). Right-to-left differences and associations with Wingate Anaerobic Test outcomes are analyzed.
Wingate Anaerobic Test Peak Power
Time frame: Day 2 of testing (single measurement session)
Highest power output (W) achieved during the 30-second Wingate Anaerobic Test performed on a mechanically braked cycle ergometer with a braking load of 0.075 kg per kg of body mass.
Secondary measures
Conventional Hamstring-to-Quadriceps (H/Q) Strength Ratio
Time frame: Day 1 of testing
Concentric hamstring peak torque divided by quadriceps peak torque, multiplied by 100 (%), calculated for each limb at 60, 120, and 180 degrees per second.
Wingate Anaerobic Test Mean Power
Time frame: Day 2 of testing
Average power output (W) maintained across the 30-second Wingate Anaerobic Test.
Wingate Anaerobic Test Fatigue Index
Time frame: Day 2 of testing
Percentage decline from peak power to the lowest power output during the test: \[(peak power - minimum power) / peak power\] × 100.
Review the complete result tables and limitations in the official record.
Open official results ↗Research locations (1)
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1 locations
Department of Physical Education and Sport Teaching, Faculty of Sports Sciences, Inonu University,Malatya, Malatya, Turkey (Türkiye)Status unknown
Study team and timeline
- Lead sponsor
- Inonu University
- Study start
- Dec 28, 2026 Estimated
- Primary completion
- Jan 28, 2027 Estimated
- Study completion
- Jan 28, 2027 Estimated
- First posted
- Nov 6, 2026 Actual
- Last updated
- Nov 10, 2026 Actual
Official study contacts
Official study title
Relationship of Isokinetic Knee Strength and Bilateral Muscle Balance With Anaerobic Performance in Adolescent Athletes
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Retrieved: Nov 12, 2026 · Last registry update: Nov 10, 2026