The Addition of Core Muscle Training on Tennis Serve Speed in Tennis Players

July 24, 2026 updated by: Ahmed ElMelhat, Cairo University

The Effect of Adding Core Muscle Training With Shoulder Strengthening in Tennis Players: A Randomized Controlled Trial

Compared with shoulder-only training and with continued tennis training alone, will the addition of core strengthening to shoulder training produce significantly greater improvements in flat serve ball speed in healthy tennis players?

Secondary Hypothesis:

  • Combined core + shoulder training will produce greater improvement in serve accuracy than shoulder-only training or tennis training alone.
  • Combined core + shoulder training will produce greater improvement in TGAR than shoulder-only training or tennis training alone.
  • Combined core + shoulder training will produce greater improvement in core strength/endurance and shoulder rotational strength than the comparator groups.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

The kinetic chain model suggests that core musculature plays a crucial role in transferring energy from the lower body to the upper extremity during the tennis serve. However, evidence on the relationship between core strength and tennis serve (TS) ball speed and passive total glenohumeral arc of rotation (TGAR) remains inconsistent, warranting further investigation.

It is hypothesized that the addition of core muscle exercises to the training program would yield greater improvements in terms of tennis serve ball speed and TGAR when compared to a control group performing only shoulder exercises in tennis players.

Tennis players with at least 1-3 years of weekly tennis training will be included and allocated randomly into the control group (CG) and experimental group (EG). CG participants will perform shoulder exercises and sham core exercises. EG participants will receive the same training as CG in addition to performing core exercises. Both groups will participate in a 12-week intervention (2 sessions per week, 50 minutes per session). Pre- and postintervention assessments will include TS ball speed analysis and TGAR, respectively.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
120

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • Lebanon
    • Beirut
      • Beirut, Beirut, Lebanon, 1100
        • Recruiting
        • Beirut Arab University
        • Contact:
    • Giza
      • Beirut, Giza, Lebanon, 2356
        • Recruiting
        • BAU activities
        • Contact:
        • Contact:
          • Ahmed ELMelhat, PhD

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Healthy adults aged 18-35 years
  • Recreational to competitive non-professional tennis players (currently playing ≥2 sessions/week for ≥1 year; NTRP 3.0-5.0 or equivalent ITN; no professional ranking or tour-level competition history)
  • Right- or left-hand dominant (serve arm recorded)
  • Able to perform a full flat serve without pain
  • Willing to maintain current tennis training routine and refrain from starting other new strength/conditioning programs during the study

Exclusion Criteria:

  • Current or history of shoulder pain/injury in the past 6 months (e.g., rotator cuff pathology, labral injury, impingement)
  • Low back pain or lumbar spine pathology in the past 6 months
  • Prior shoulder or spine surgery
  • Systemic conditions affecting neuromuscular function (e.g., uncontrolled diabetes, neurological disorders)
  • Pregnancy
  • Current participation in a structured core or shoulder strengthening program

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Other
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Active Comparator: Shoulder+ sham core
Shoulder strengthening + sham/placebo core exercises (non-loading trunk mobility).
Other: Shoulder Strengthening Program+ Sham core Treatment

Delivered 2×/week for 10 weeks under supervision of a licensed physical therapist or certified strength and conditioning specialist. Progressive resistance program including:

  • External/internal rotation strengthening (resistance band, cable, or dumbbell) at 0° and 90° abduction
  • Scapular stabilization exercises (rows, Y-T-W raises, serratus punch)
  • Posterior shoulder stretching (sleeper stretch, cross-body stretch) for the TGAR component
  • Progressive overload every 2 weeks based on tolerated resistance/repetitions

Sham :Low-intensity, non-progressive trunk mobility exercises with minimal loading (e.g., seated trunk rotations without resistance, cat-camel stretches), matched for session time and attention to control for non-specific training effects, without targeting core strength/endurance adaptation.
Experimental: shoulder strengthening exercises+ core strengthening
Participants in EG performed the same shoulder strengthening exercises as in CG, coupled with a physical therapy core strengthening program.
Other: Shoulder Strengthening Program+ Core Strengthening Program

Delivered 2×/week for 10 weeks, same sessions as the shoulder program (combined ~50-60 minute sessions), progressive core program including:

  • Anti-rotation exercises (Pallof press)
  • Rotational power exercises (medicine ball rotational throws, cable woodchoppers)
  • Anterior/lateral/posterior chain stability (plank variations, side plank, bird-dog)
  • Progressive overload via increased resistance, hold time, or instability surface every 2 weeks

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Flat serve ball speed
Time Frame: measured at baseline (Week 0) and post-intervention (Week 12).
Flat serve ball speed (km/h or mph), measured via radar gun (e.g., Stalker Pro II) or equivalent validated device, averaged across the best 5 of 10 flat serves hit into the deuce-side service box, measured at baseline (Week 0) and post-intervention (Week 12).
measured at baseline (Week 0) and post-intervention (Week 12).

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Serve accuracy
Time Frame: measured at baseline (Week 0) and post-intervention (Week 12).
  • Target-based scoring system: standardized service box divided into scoring zones (e.g., 5 concentric/quadrant zones worth 1-5 points); participant hits 10 flat serves aimed at a designated target zone (e.g., wide serve to deuce court corner); accuracy score = mean points across 10 serves.
  • Recorded simultaneously with ball speed trials (speed-accuracy trade-off examined as an exploratory outcome).
measured at baseline (Week 0) and post-intervention (Week 12).
Total glenohumeral arc of rotation (TGAR)
Time Frame: measured at baseline (Week 0) and post-intervention (Week 12).
● Passive internal rotation (IR) + external rotation (ER) range of motion measured via goniometry (or inclinometer) with scapula stabilized, participant supine, shoulder abducted to 90°, elbow flexed to 90°. TGAR = IR + ER (degrees). Measured bilaterally.
measured at baseline (Week 0) and post-intervention (Week 12).
Shoulder rotational strength
Time Frame: measured at baseline (Week 0) and post-intervention (Week 12).
● Peak IR and ER isometric or isokinetic torque (Nm), measured via hand-held dynamometer (standardized stabilization protocol) or isokinetic dynamometer (60°/sec and 180°/sec) if available, at 0° abduction. ER/IR strength ratio calculated. Measured bilaterally.
measured at baseline (Week 0) and post-intervention (Week 12).
Core strength/endurance
Time Frame: measured at baseline (Week 0) and post-intervention (Week 12).
● McGill core endurance battery: trunk flexor endurance test (seconds), bilateral side-bridge/plank endurance test (seconds).
measured at baseline (Week 0) and post-intervention (Week 12).

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Cairo University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
June 15, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
September 15, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
September 20, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
July 21, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 24, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
July 29, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
July 29, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 24, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
July 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • Core Vs shoulder in tennis

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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