Adductor Endurance Test: Validity and Reliability

Validity and Reliability of the Adductor Endurance Test Developed for the Hip Adductor Muscles

Groin and hip injuries are common in team sports-especially soccer, rugby, and ice hockey-and frequently affect male and young athletes. About 14% of all sports injuries involve the groin and hip region, with most related to the adductor muscles. These injuries often increase during congested match periods and may result in athletes missing 1 to 6.9 weeks of training or competition, extending up to 14 weeks when surgery is required. Weakness in the adductor muscles is a key risk factor for groin injuries, and current assessments primarily measure maximal strength using tools such as squeeze tests, sphygmomanometers, or dynamometers. However, muscle endurance-critical because many injuries occur under fatigue-has not been adequately studied, and no validated endurance tests for the hip adductors exist. This study aims to evaluate the validity and reliability of a newly developed hip adductor endurance test for monitoring endurance strength in professional soccer players.

Study Overview

• Status: Not yet recruiting
• Conditions: Hip Injuries; Athletic Injuries; Groin Injury
• Intervention / Treatment: Other: Hip Adductor Endurance and Strength Testing

Detailed Description

Groin and hip injuries are common in various team sports such as soccer, rugby, and ice hockey, and are particularly prevalent among male athletes and young athletes aged 15-24 . Studies show that approximately 14% of all injuries occur in the groin and hip regions, and 63% of these are directly related to the adductor muscles . Furthermore, these injuries increase during periods when matches are played at frequent intervals. Research conducted by the Union of European Football Associations (UEFA) within the scope of the Champions League has reported an injury rate of 1.1 per 1,000 match hours for this type of injury. A significant consequence of these injuries is that players are unable to participate in training or matches for an average of 1 to 6.9 weeks ; when surgical intervention is required, this period can extend up to 14 weeks . This situation strains the financial resources of clubs and negatively affects the overall performance of the team . Given the importance of these injuries, it is crucial to regularly monitor athletes' health and take protective measures when necessary . Weakness in the adductor muscles is an important risk factor in predicting groin and hip injury risk. Adductor muscle strength measurements are usually performed using the hip adductor squeeze test, which is both accurate and reliable. During the test, a measuring device is placed between the player's knees, and they are asked to squeeze their legs together. Research has shown that decreased adductor muscle strength may indicate a risk of groin pain development in soccer players. Furthermore, it has been reported that previously injured athletes have weaker adductor muscles compared to uninjured athletes before the season. This information has led to the development of new monitoring methods to detect early signs of muscle weakness in athletes throughout the season and to initiate strengthening exercises. Therefore, the availability and development of easily applicable tests to determine muscle strength may be beneficial for coaches and physical therapists in preventive interventions.

Various technologies such as sphygmomanometers, isometric dynamometers, and isokinetic dynamometers are used to measure adductor strength. In these measurements, peak force variables obtained during isometric contraction of the adductor muscles are recorded. However, all of these methods have been developed to assess the maximum muscle strength of the adductor muscles. Since the vast majority of muscle injuries develop after muscle fatigue, assessing the muscles' ability to resist force over a long period of time may be indicative in predicting muscle injuries. However, there are no studies in the scientific literature on tests used to measure muscle endurance, which is the ability of the hip adductor muscles to resist prolonged force.

The aim of this study is to examine the validity and reliability of the hip adductor endurance test, which will be used to measure hip adductor endurance strength in professional soccer players.

• Study Type: Interventional
• Enrollment (Estimated): 18
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Ferruh Taspinar, Prof.Dr.; Phone Number: +90542 685 38 77; Email: ferruh.taspinar@idu.edu.tr
• Study Contact Backup: Name: Ezgi ÜNÜVAR YÜKSEL, Asst.Prof.; Phone Number: +905078337676; Email: ezgi.unuvaryuksel@idu.edu.tr

Study Locations

• Turkey (Türkiye)
  • Izmir, Turkey (Türkiye), 35000
    • Izmir Democracy Univercity

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Being between 18 and 30 years of age
• Being a professional soccer player for at least four years
• Actively participating in training sessions
• Scoring >87.5 points on the hip and groin injury questionnaire (HAGOS) sports subscale

Exclusion Criteria:

• Having any orthopedic injury involving the lower extremities that would prevent participation in training sessions
• Experiencing pain rated four or higher on the numerical pain rating scale during the hip adductor squeeze test and palpation of the adductor muscle tendons.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Test Group; Participants perform the Hip Adductor Endurance Test and GroinBar isometric strength test in randomized order.	Other: Hip Adductor Endurance and Strength Testing; Participants will perform the Hip Adductor Endurance Test to assess adductor muscle endurance, followed by isometric maximum force assessment using the fixed dynamometer (GroinBar) . Tests are conducted in randomized order before routine training sessions, after a 5-minute light aerobic warm-up and dynamic stretching

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pain Assessment	Pain felt during the adductor squeeze test and adductor palpation test, which are applied for inclusion/exclusion criteria, will be assessed using the Numerical Pain Rating Scale. The patient will be asked to mark the level of pain they feel on a 10 cm line, and the marked location will then be measured with a ruler and recorded.	baseline
Evaluation of Maximum Isometric Muscle Strength of the Hip Adductor Muscles	Hip adductor strength of both lower extremities will be assessed simultaneously using the GroinBar fixed dynamometer (VALD Performance, Australia), a highly reliable method (ICC=0.94). Strength will be measured in two positions: short lever arm (hips 60°, knees 90° flexed, force applied at medial knee epicondyles) and long lever arm (hips and knees extended, force applied 5 cm proximal to medial malleoli). Athletes perform three 5-second maximal isometric contractions per position, with 5-10 seconds rest between repetitions and 20-30 seconds between positions. A trial at 80% of maximal effort is allowed before measurement. Verbal encouragement is provided, and the highest values in Newtons (N) for both dominant and non-dominant legs are recorded; strength ratios are subsequently calculated.	baseline
Hip Adductor Endurance Test	Hip adductor endurance will be assessed using a time-based version of the Copenhagen Adduction Exercise, which elicits high adductor activation. Participants lie on their side, lift their body concentrically, hold the isometric position as long as possible, and lower eccentrically. The test focuses on maintaining correct alignment and endurance duration rather than maximal force, converting the Copenhagen exercise into an endurance assessment protocol.	baseline

Collaborators and Investigators

• Sponsor: Izmir Democracy University
• Investigators: Principal Investigator: Betül Taspinar, Prof.Dr., Izmir Democracy University; Study Director: Ayşe Sezgi Kızılırmak Karataş, Pt.PhD, Izmir Democracy University; Study Director: Mesut Buğday, Pt., Göztepe Sports Club

Study record dates

Study Major Dates

• Study Start (Estimated): April 15, 2026
• Primary Completion (Estimated): September 15, 2026
• Study Completion (Estimated): October 15, 2026

Study Registration Dates

• First Submitted: December 9, 2025
• First Submitted That Met QC Criteria: December 9, 2025
• First Posted (Estimated): December 22, 2025

Study Record Updates

• Last Update Posted (Actual): December 30, 2025
• Last Update Submitted That Met QC Criteria: December 23, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: Validity; Reliability; Sports injuries; Hip adductor muscles; Adductor endurance
• Additional Relevant MeSH Terms: Wounds and Injuries; Athletic Injuries; Hip Injuries
• Other Study ID Numbers: HAET-VR-35

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