Association Between Racket Stiffness and Lateral Epicondylalgia in Tennis Players

Association Between Racket Stiffness and Lateral Epicondylalgia in Tennis Players: A Multicenter Observational Study

Background. Lateral epicondylalgia is common in tennis and is associated with pain and functional limitation. Although racket stiffness has been experimentally linked to vibration transmission, its clinical association with this condition in tennis players remains insufficiently studied.

Objective. To evaluate the association between racket stiffness and the presence of lateral epicondylalgia in adult tennis players, and to examine the potential effect modification by sex and competitive level on this association.

Methods. An analytical observational study with a cross-sectional design will be conducted. A total of 200 athletes will be recruited. The primary outcome will be the presence of lateral epicondylalgia within the previous 12 months. Functional severity will be assessed using the Patient-Rated Tennis Elbow Evaluation Questionnaire. The main independent variable will be racket stiffness (RA/stiffness). Secondary variables will include string age, use of a vibration dampener, and exposure related to playing load and technique. Potential confounders will include sex, competitive level, age, anthropometric characteristics, smoking status, prior history of elbow pain, occupational ergonomics involving repetitive gripping (ISO 11228-3 criteria), sleep quality (Pittsburgh Sleep Quality Index), and racket characteristics. The prevalence of lateral epicondylalgia will be estimated, and multivariable logistic regression models will be used to assess the association between racket stiffness and lateral epicondylalgia, including interaction terms to evaluate effect modification by sex and competitive level.

Expected results. To determine the prevalence of lateral epicondylalgia in adult tennis players and to identify the association between racket stiffness and the presence of this condition, as well as the potential modifying effects of sex and competitive level.

Study Overview

• Status: Active, not recruiting
• Conditions: Tennis Elbow
• Intervention / Treatment: Other: Adult tennis players

• Study Type: Observational
• Enrollment (Actual): 207

Contacts and Locations

Study Locations

• Spain
  • Principality of Asturias
    • Oviedo, Principality of Asturias, Spain, 33006
      • Universidad de Oviedo

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

Adult tennis players

Description

Inclusion Criteria:

• Tennis players aged 16 years or older.
• Regular tennis practice over the previous 12 months, defined as at least one weekly training or competition session.
• Habitual use of an adult tennis racket weighing more than 280 grams for training and competition for a minimum period of three months prior to data collection.
• Provision of written informed consent. Players with a history of elbow pain related to tennis practice will be eligible for inclusion and this information will be recorded as an independent clinical variable.

Exclusion Criteria:

• Players with a history of upper-limb surgery within the previous year.
• Athletes with a prior medical diagnosis of neurological or rheumatological disease that could affect the upper limb.
• Athletes who sustained an acute traumatic injury to the shoulder, elbow, or wrist within the six months preceding the study.
• Participants who fail to complete the study questionnaires correctly.

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Observacional group; Adult tennis players in whom the association between racket stiffness and the presence of lateral epicondylalgia will be evaluated, including an analysis of the potential effect modification by sex and competitive level on this association.	Other: Adult tennis players; Adult tennis players in whom the association between racket stiffness and the presence of lateral epicondylalgia will be evaluated, including an analysis of the potential effect modification by sex and competitive level on this association.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Measurement of Clinical of lateral epicondylalgia within the previous 12 months.	Lateral epicondylalgia will be assessed using the Patient-Rated Tennis Elbow Evaluation (PRTEE) Questionnaire. This instrument evaluates pain and functional disability in individuals with lateral epicondylalgia. The questionnaire consists of 15 items. The total PRTEE score is transformed to a 0-100 scale, where 0 indicates no pain or disability and 100 represents the worst possible pain and functional impairment.	Screening visit

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Measurement of racket stiffness.	Racket stiffness will be assessed using the measured stiffness value (RA) or stiffness index. As not all racket models report this parameter, when participants are unaware of the RA value, it will be determined based on the exact brand, model, and year of manufacture, and subsequently obtained from manufacturer catalogs or technical reference tables. The unit of measurement will be the RA rating (Racquet Analysis rating), also referred to as the stiffness index.	Screening visit
Measurement of string age.	String age will be measured as the number of months since the last restringing. This variable will be used as a mechanical proxy for string condition, as commonly applied in biomechanical studies and technical-sport performance recommendations.	Screening visit
Measurement of vibration dampener use	Vibration dampener use will be recorded as a dichotomous variable (yes/no). When applicable, the specific dampener model will be documented. This variable is a recognized modifier of the vibratory spectrum, as described in experimental studies.	Screening visit
Measurement of load exposure and playing technique	In this variable, data will be collected on the number of weekly training hours (measured in hours/week).	Screening visit
Measurement of load exposure and technique.	In this variable, data will be collected on the years of tennis practice (number of years).	Screening visit
Measurement of load exposure and technique.	In this variable, data will be collected on the number of weekly matches (matches/week).	Screening visit
Measurement of load exposure and technique.	In this variable, data will be collected on upper-limb dominance (right / left).	Screening visit
Measurement of load exposure and technique.	In this variable, data will be collected on whether the athlete performs specific weekly upper-limb strength training (yes / no).	Screening visit
Measurement of load exposure and technique.	In this variable, data will be collected on the number of weekly strength training hours.	Screening visit
Measurement of load exposure and technique.	In this variable, data will be collected on backhand execution (one-handed / two-handed).	Screening visit
Measurement of load exposure and technique.	In this variable, data will be collected on competitive level (occasional recreational (≤1 session/week; no tournaments); regular recreational (2-3 sessions/week; occasional local leagues); regional competitive	Screening visit

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Measurement of gender	This will be the variable acting as an a priori effect modifier, with an RA×sex interaction term included in the models, given that sex-related differences in injury patterns have been reported in padel and contextual differences have	Screening visit
Measurement of competitive level	This will be assessed using a dichotomous variable (Federated / Non-federated). This variable will act as a potential effect modifier (RA×competitive level), as exposure level, technique, and equipment differ between rec	Screening visit
Measurement of age	Age will be measured in years	Screening visit
Measurement of body weight.	This variable will be measured in kilograms (kg)	Screening visit
Measurement of height	This variable will be measured in meters (m)	Screening visit
Measurement of smoking status	Smoking status will be recorded as a dichotomous variable (yes/no). This variable is included because some studies have shown that individuals with a history of smoking present higher odds of developing the condition compared with controls.	Screening visit
Measurement of previous history of elbow pain	This variable will be assessed using ISO 11228-3 screening criteria and temporal exposure. Three dichotomous items anchored to the ISO 11228-3 criteria for repetitive upper-limb tasks will be used, along with a quantification of exposure time in hours per week.	Screening visit
Measurement of sleep quality	Sleep quality will be assessed using the Pittsburgh Sleep Quality Index. This scale measures global sleep quality over the previous month, including aspects such as sleep latency, duration, efficiency, sleep disturbances, use of sleep medication, and daytime dysfunction. It consists of 19 items grouped into seven domains, with a total score ranging from 0 to 21 (higher scores indicate poorer sleep quality; scores >5 indicate poor sleep quality).	Screening visit

Collaborators and Investigators

• Sponsor: University of Oviedo
• Investigators: Principal Investigator: Rubén Cuesta-Barriuso, PhD, Universidad de Oviedo

Study record dates

Study Major Dates

• Study Start (Actual): February 13, 2026
• Primary Completion (Actual): April 1, 2026
• Study Completion (Estimated): May 11, 2026

Study Registration Dates

• First Submitted: February 5, 2026
• First Submitted That Met QC Criteria: February 5, 2026
• First Posted (Actual): February 12, 2026

Study Record Updates

• Last Update Posted (Actual): May 1, 2026
• Last Update Submitted That Met QC Criteria: April 27, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: Equipment Design; Sports Injuries; Pain Measurement; Tennis Elbow
• Additional Relevant MeSH Terms: Elbow Tendinopathy; Elbow Injuries; Musculoskeletal Diseases; Muscular Diseases; Wounds and Injuries; Tendon Injuries; Arm Injuries; Tendinopathy; Athletic Injuries; Tennis Elbow
• Other Study ID Numbers: TENrig

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No