The Effect of Training Frequency on Explosive Strength in Adolescent Tennis Players During a Six-Week Functional Training Program

NCT07398547 | Completed

• 1 other identifier: 1071
• Study Type: interventional
• Target: 30
• Locations: 1 country
• Sites: 1

Brief Summary

Adolescence is a period characterized by rapid growth and development, characterized by intense structural, functional, and neuromuscular changes in the musculoskeletal system. The rapid height growth and proportional changes that occur during this period can negatively impact athletic performance by disrupting muscle strength and flexibility. Deficiencies in lower extremity muscle strength, in particular, can lead to decreased performance and increased injury risk in sports requiring high agility, balance, and explosive power, such as tennis. Functional training programs are holistic exercise approaches that aim to improve neuromuscular control, balance, coordination, and muscle strength by simultaneously training multiple muscle groups. This type of training is particularly important in adolescent athletes because it supports the development of strength, endurance, and explosive power. Training frequency, in turn, plays a decisive role in muscle adaptation and performance enhancement by influencing the balance between loading and recovery. Literature contains limited studies directly examining the effects of functional training frequency on explosive power performance in young athletes. Most existing research has focused on adult or professional athletes, and experimental studies comparing the effects of different training frequencies in adolescent tennis players are insufficient. In this context, the aim of our study was to examine the effects of a six-week functional training program implemented at different training frequencies on lower extremity explosive strength parameters in adolescent tennis athletes.

Conditions

Exercise Therapy

Keywords

adolescent tennis players; explosive strength; performance development; functional training

Outcome Measures

Primary Outcomes (5)

• Countermovement Jump Test (CMJ)

  The participant performs a rapid squat from an upright position with hands on hips, followed by a maximum vertical jump. This assesses lower extremity explosive strength and elastic energy utilization.

  6 weeks

• Squat Jump (SJ) Test

  The participant is fixed in a position of approximately 90° flexion of the knee and hip joints, then performs a maximum vertical jump without using the arms. It measures pure concentric muscle strength.

  6 weeks

• Reactive Strength Index (RSI) Test

  It's typically performed using a drop jump protocol. The participant jumps onto the platform from a specific height and bounces back up as quickly as possible after contact with the ground. RSI is calculated based on jump height and ground contact time; it measures reactive strength and stretch-shortening cycle (SSC) effectiveness.

  6 weeks

• Standing Long Jump (SLJ) Test

  The participant stands with their feet parallel and jumps as far forward as possible using their arms. Lower extremity explosive strength is assessed by measuring the jump distance.

  6 weeks

• Assessment of normal joint motion

  The Normal Joint Motion Assessment (NJM) Test is an objective method used to measure joint range of motion. In the study, participants' hip and knee joint flexion and extension angles will be assessed using the NJM test using a universal goniometer. Measurements will be made using active range of motion, and each measurement will be repeated three times and averaged.

  6 weeks

Study Arms (2)

Low-Frequency Functional Training Group (LFFT)

OTHER

Participants in this group performed the functional training program once per week for six consecutive weeks. Each session lasted approximately 60 minutes and included dynamic warm-up, multi-joint functional exercises, and cool-down activities supervised by the same physiotherapist.

Other: Low-Frequency Functional Training Group (LFFT)

High-Frequency Functional Training Group (HFFT)

EXPERIMENTAL

Participants in this group performed the same functional training program three times per week for six consecutive weeks. Each 60-minute session followed the same structure as the low-frequency program and was conducted under identical supervision and environmental conditions.

Other: High-Frequency Functional Training Group (HFFT)

Interventions

High-Frequency Functional Training Group (HFFT) OTHER

Participants in this group performed the same functional training program three times per week for six consecutive weeks. Each 60-minute session followed the same structure as the low-frequency program and was conducted under identical supervision and environmental conditions.

Also known as: exercise

High-Frequency Functional Training Group (HFFT)

Low-Frequency Functional Training Group (LFFT) OTHER

Participants in this group performed the same functional training program once per week for six consecutive weeks. Each 60-minute session followed the same structure as the low-frequency program and was conducted under identical supervision and environmental conditions.

Also known as: exercise

Low-Frequency Functional Training Group (LFFT)

Eligibility Criteria

• Age: 12 Years - 18 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Child (0-17), Adult (18-64)

You may qualify if:

• Adolescent tennis players aged 12-18 years.
• Have at least two years of regular tennis training history.
• Regularly practice tennis at least three days a week.
• Have not had an acute injury or surgery affecting the lower extremities in the last six months.
• Have the physical ability to fully complete explosive strength tests (CMJ, SJ, SLJ, RSI).
• Individuals who voluntarily agreed to participate in the study and provided written consent from their parents.

You may not qualify if:

• Those with ongoing pain, instability, or deformity in the knee, hip, ankle, or spine area.
• Those who have undergone a musculoskeletal physical therapy or rehabilitation program within the last 6 months.
• Those with a systemic disease that may affect neurological, vestibular, or balance.
• Those who experience pain or fatigue to the extent that they cannot complete postural analysis or performance tests.
• Those who do not have a regular sports history or have not trained regularly in the last 3 months.
• Participants who exhibited a lack of cooperation during the assessment process that could compromise measurement consistency.

Sponsors & Collaborators

• Biruni University: lead

Study Sites (1)

Sportplus Tennis Academy

Istanbul, Maltepe, 34844, Turkey (Türkiye)

Location

Related Publications (7)

• Axman S, Stausholm MB, Volk NR, Ferrauti A, Magnusson SP, Couppe C. Physical Performance Tests in 8008 Competitive Youth Tennis Players-A Systematic Review and Meta-Analysis of Normative Values. Eur J Sport Sci. 2025 Sep;25(9):e70023. doi: 10.1002/ejsc.70023.

  PMID: 40884448 RESULT

• Colomar J, Baiget E, Corbi F. Influence of Strength, Power, and Muscular Stiffness on Stroke Velocity in Junior Tennis Players. Front Physiol. 2020 Mar 6;11:196. doi: 10.3389/fphys.2020.00196. eCollection 2020.

  PMID: 32210838 RESULT

• Myer GD, Faigenbaum AD, Ford KR, Best TM, Bergeron MF, Hewett TE. When to initiate integrative neuromuscular training to reduce sports-related injuries and enhance health in youth? Curr Sports Med Rep. 2011 May-Jun;10(3):155-66. doi: 10.1249/JSR.0b013e31821b1442.

  PMID: 21623307 RESULT

• Fernandez-Fernandez J, Ulbricht A, Ferrauti A. Fitness testing of tennis players: how valuable is it? Br J Sports Med. 2014 Apr;48 Suppl 1(Suppl 1):i22-31. doi: 10.1136/bjsports-2013-093152.

  PMID: 24668375 RESULT

• Markovic G, Mikulic P. Neuro-musculoskeletal and performance adaptations to lower-extremity plyometric training. Sports Med. 2010 Oct 1;40(10):859-95. doi: 10.2165/11318370-000000000-00000.

  PMID: 20836583 RESULT

• Castro-Pinero J, Ortega FB, Artero EG, Girela-Rejon MJ, Mora J, Sjostrom M, Ruiz JR. Assessing muscular strength in youth: usefulness of standing long jump as a general index of muscular fitness. J Strength Cond Res. 2010 Jul;24(7):1810-7. doi: 10.1519/JSC.0b013e3181ddb03d.

  PMID: 20555277 RESULT

• Noyes FR, Barber SD, Mangine RE. Abnormal lower limb symmetry determined by function hop tests after anterior cruciate ligament rupture. Am J Sports Med. 1991 Sep-Oct;19(5):513-8. doi: 10.1177/036354659101900518.

  PMID: 1962720 RESULT

MeSH Terms

Interventions

Exercise

Intervention Hierarchy (Ancestors)

Motor Activity; Movement; Musculoskeletal Physiological Phenomena; Musculoskeletal and Neural Physiological Phenomena

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: PhD

Model Details: Our study is designed as a prospective, two-group experimental study. Participants will be randomly assigned to two groups: the first group will participate in a 60-minute functional training program once a week, and the second group will participate in a 60-minute functional training program three times a week. At the end of the six-week program, the effects of training frequency will be assessed by comparing changes in explosive strength performance across groups.

Study Record Dates

• First Submitted: January 24, 2026
• First Posted: February 10, 2026
• Study Start: February 10, 2026
• Primary Completion: March 30, 2026
• Study Completion: April 5, 2026
• Last Updated: April 28, 2026

Record last verified: 2026-04

Locations

TU (1)