The Effectiveness of Two Different Interventions on Hip Adduction Strength in Junior Floorball Players

The Effectiveness of Two Different Interventions on Hip Adduction Strength in Junior Floorball Players - A Randomized Controlled Trial

Study type The present study is a two- armed randomized controlled trial. Study setting and participants 50 floorball players in high-school level will be invited to participate. An a priori power calculation indicated that 40 participants are required to detect an effect size of 0,3, with a significance level of 0.05 and a statistical power of 80%.

Recruitment and study procedure The recruitment will be performed in two steps; (1) The project will be presented to responsible floorball coaches at one high-school with the aim to get consent to contact the players in their floorball group. (2) The Research Group will visit the players to ask for individual consent.

Baseline assessment Three assessments will be performed: (a) questionnaire including demographic data, injury history, history of adductor strength training and information dominant leg, history of lower limb and lower back problems and previous experience of groin specific strength training. (b) eccentric hip adductor strength measured with a handheld dynamometer (c) isometric hip adductor and abductor strength measured with the ForceFrame Strength System (VALD).

Randomization, stratification and statistical analysis Randomization will follow an individual-randomization procedure. Randomization will take place after completion of baseline strength measurements. Allocation followed a 1:1 ratio, where the two intervention groups are equal in size. All stratification follows the allocation described under "Randomization" above.

The following variables will be stratified: Sex, and eccentric hip adductor strength (measured with a handheld dynamometer) at baseline. Analyses will follow the intention-to-treat principle using mixed-effects models.

Intervention

The intervention will consist of two parallel groups:

• Progressive training program using the Copenhagen Adductor Exercise (CAE).
• Progressive training program using the Adductor Slide (AS). The interventions followed a progressive protocol. The exercise was incorporated into the participants' regular training and took approximately 10 minutes on the days the intervention was performed. The intervention protocol for both groups followed an 8-week progressive loading structure with gradual increases in training volume over time. During week 1, participants completed 2 sessions per week, performing 2 sets of 6 repetitions per side. In weeks 2 and 3, the number of repetitions was increased to 8 and 10 per side, respectively, while maintaining the same weekly frequency and number of sets. In week 4, the number of sets was increased from 2 to 3, while repetitions remained at 10 per side. During weeks 5 and 6, repetitions were further increased to 12 per side, followed by 15 repetitions per side during weeks 7 and 8. Overall, the protocol progressively increased training load by manipulating repetitions first, then sets, and finally maintaining a higher training volume in the final phase.

For both interventions, each repetition was performed with a 3-second eccentric phase and a 3-second concentric phase.

Implementation and adherence The intervention was supervised by the research group. Attendance was recorded at each intervention session.

Follow-up assessment Three assessments were performed: (a) questionnaire assessing how the players experienced the intervention, if any adverse events occured, their motivation to perform the intervention and if they experienced DOMS (delayed onset muscle soreness) during the intervention (b) eccentric hip adductor strength measured with a handheld dynamometer (c) isometric hip adductor and abductor strength measured with the ForceFrame Strength System (VALD).

Outcome variables and analyses. Between-group effects will be calculated. Main outcome variables will be;

• Eccentric hip adductor strength (measured with handheld dynamometer). The unit used will be Nm/kg.
• Isometric hip adductor and abductor strength (measured with the ForceFrame Strength System, VALD). The unit used will be Nm/kg.
• Ratio between isometric hip adductor and isometric hip abductor strength (measured with the ForceFrame Strength System, VALD). Percentage (i.e a measure of the strength balance between the hip adductors and abductors. Lower values indicate relatively weaker adductors compared with abductors) will be calculated to express this ratio. Potential confounders that will be analyzed as interactions will include;
• Attendance to the intervention
• Motivation to perform the intervention
• Experienced DOMS
• Contamination (i.e if the participant performed hip adductor specific training outside the intervention).

Study Overview

• Status: Completed
• Conditions: Hip Adduction; Hip Adduction Strength
• Intervention / Treatment: Other: Copenhagen Adductor Exercise; Other: Adductor Slide

• Study Type: Interventional
• Enrollment (Actual): 49
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Sweden
  • Västerbotten County
    • Umeå, Västerbotten County, Sweden, 90187
      • Umeå Energi Arena

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Floorball players between 16-20 years old
• Not actively using any of the interventions in their daily training

Exclusion Criteria:

• Pain or injury to the lower extremities or lower back that hinders the person from performing the assigned intervention

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Copenhagen Adductor Exercise; The Copenhagen Adduction exercise protocol followed an 8-week progressive loading structure with gradual increases in training volume over time. During week 1, participants completed 2 sessions per week, performing 2 sets of 6 repetitions per side. In weeks 2 and 3, the number of repetitions was increased to 8 and 10 per side, respectively, while maintaining the same weekly frequency and number of sets. In week 4, the number of sets was increased from 2 to 3, while repetitions remained at 10 per side. During weeks 5 and 6, repetitions were further increased to 12 per side, followed by 15 repetitions per side during weeks 7 and 8. Overall, the protocol progressively increased training load by manipulating repetitions first, then sets, and finally maintaining a higher training volume in the final phase. Each repetition is performed with a 3-second eccentric phase and a 3-second concentric phase.	Other: Copenhagen Adductor Exercise; The Copenhagen Adductor Exercise is performed with a partner and primarily targets the hip adductor muscles. The athlete begins in a side plank position with the lower forearm placed directly under the shoulder and the body held in a straight line. A partner stands beside the athlete and supports the upper leg by holding the ankle and, if needed, the knee. The lower leg remains free beneath the body. From the starting position, the athlete lifts the body upward by pressing the supported upper leg down into the partner's hands while simultaneously raising the lower leg to meet the upper leg. The body should remain straight and stable throughout the movement, with the hips kept elevated and aligned. The athlete then slowly lowers the lower leg back to the starting position in a controlled manner while maintaining trunk stability. After completing the prescribed repetitions on one side, the exercise is repeated on the opposite side.; Other Names: CAE
Active Comparator: Adductor Slide; The Adductor Slide exercise protocol followed an 8-week progressive loading structure with gradual increases in training volume over time. During week 1, participants completed 2 sessions per week, performing 2 sets of 6 repetitions per side. In weeks 2 and 3, the number of repetitions was increased to 8 and 10 per side, respectively, while maintaining the same weekly frequency and number of sets. In week 4, the number of sets was increased from 2 to 3, while repetitions remained at 10 per side. During weeks 5 and 6, repetitions were further increased to 12 per side, followed by 15 repetitions per side during weeks 7 and 8. Overall, the protocol progressively increased training load by manipulating repetitions first, then sets, and finally maintaining a higher training volume in the final phase.	Other: Adductor Slide; The Adductor Slide is performed in standing and targets the hip adductors while also challenging balance and trunk control. The athlete stands with one foot on a sliding surface and the other firmly planted on the floor. A resistance band is placed around the ankle of the sliding leg and positioned to pull the leg laterally away from the body. The athlete slowly slides the leg out to the side while bending the stance leg into a controlled side-lunge position, keeping the trunk upright and pelvis stable. The sliding leg is then actively pulled back to the starting position against the resistance of the band using the hip adductor muscles. The movement should be slow and controlled. After completing the prescribed repetitions, the exercise is repeated on the opposite side. Each repetition is performed with a 3-second eccentric phase and a 3-second concentric phase.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes in eccentric adduction strength after 8 week training period	Eccentric adduction strength measured with a handheld dynamometer	Measured at baseline (pre intervention) and directly after the intervention (post intervention). Post intervention = Intervention ends on a Friday, post-intervention testing will be performed during the upcoming 14 days.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes in isometric adduction strength and abduction strength after 8 week training period	Isometric adductor strength and abductor strength measured with a stationary strength testing system (VALD ForceFrame)	Pre and post intervention. Pre Intervention = Maximum 14 days before the intervention starts. Post intervention = Intervention ends on a Friday, post-intervention testing will be performed during the upcoming 14 days.
Changes in ratio between isometric adduction strength and abduction strength after 8 week training period	Ratio between isometric adduction strength and abduction strength measured with a stationary strength testing system (VALD ForceFrame)	Measured at baseline (pre intervention) and directly after the intervention (post intervention). Post intervention = Intervention ends on a Friday, post-intervention testing will be performed during the upcoming 14 days.

Collaborators and Investigators

• Sponsor: Umeå University
• Investigators: Principal Investigator: Apostolos Theos, PhD, Umeå University; Principal Investigator: Kajsa Gilenstam, PhD, Umeå University

Study record dates

Study Major Dates

• Study Start (Actual): January 17, 2025
• Primary Completion (Actual): June 1, 2026
• Study Completion (Actual): June 1, 2026

Study Registration Dates

• First Submitted: June 1, 2026
• First Submitted That Met QC Criteria: September 16, 2026
• First Posted (Actual): September 17, 2026

Study Record Updates

• Last Update Posted (Actual): September 17, 2026
• Last Update Submitted That Met QC Criteria: September 16, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Keywords: Hip; Groin; Adductor; Adductor Strength; Copenhagen Adductor; Adductor Slide; Hip Strength
• Other Study ID Numbers: Dnr 2024-07167-01

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: All researchers that will be working with this data are stated in this registration

Drug and device information, study documents

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