Flywheel Training Effects on Power and Performance in Youth Olympic Weightlifters (FLY-WL)

Effects of Flywheel Inertial Training on Lower-Limb Power, Trunk Stability, and Olympic Weightlifting Performance in Youth Athletes

This study investigated the effects of flywheel inertial training on lower-limb power, trunk stability, and Olympic weightlifting performance in youth athletes. Eighteen youth Olympic weightlifters were allocated to a flywheel training group or a control group. Both groups continued their regular weightlifting training over a 10-week intervention period. The experimental group performed additional flywheel-based exercises twice weekly. Outcomes included measures of lower-limb power, trunk inclination during lifting, weightlifting performance, and technical error frequency.

Study Overview

• Status: Completed
• Conditions: Sports Performance
• Intervention / Treatment: Behavioral: Flywheel Inertial Training; Behavioral: Traditional Weightlifting Training

Detailed Description

This study investigated the effects of flywheel inertial training on lower-limb power, trunk stability, and Olympic weightlifting performance in youth athletes. Flywheel training is an eccentric-overload method that has been suggested to enhance neuromuscular adaptations, particularly in power and movement control. Eighteen youth Olympic weightlifters participated in this controlled intervention study and were allocated into a flywheel training group and a control group.

Both groups continued their regular Olympic weightlifting training program, which included technical practice of the snatch and clean, strength exercises, and general physical preparation. The experimental group additionally performed flywheel-based exercises twice per week over a 10-week training period. The intervention was progressively structured to ensure appropriate load adaptation and technical execution.

Outcome measures included assessments of lower-limb power, trunk inclination during lifting positions, performance in the snatch and clean, and technical error frequency. Pre- and post-intervention comparisons were used to evaluate the effects of the training program.

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

Contacts and Locations

Study Locations

• Egypt
  • Damietta, Egypt, 34517
    • Damietta University, Faculty of Sports Science

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Male youth Olympic weightlifters aged 13-17 years
• Actively participating in structured Olympic weightlifting training
• Technical ability to perform snatch and clean lifts
• Free from musculoskeletal injury at the time of participation
• Medically fit for resistance training and high-intensity exercise

Exclusion Criteria:

• Presence of injury limiting participation in training or testing
• Absence rate greater than 20% of training or intervention sessions
• Participation in additional structured lower-limb eccentric or flywheel training outside the study program
• Any medical condition contraindicating resistance training

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Flywheel Inertial Training Group; Participants in this group performed their regular Olympic weightlifting training program combined with additional flywheel inertial training twice per week for 10 weeks. The flywheel training included lower-limb and trunk exercises such as squats, split squats, Romanian deadlifts, pulling variations, and anti-rotation core exercises. The training was progressively structured to ensure appropriate eccentric overload and technical control.	Behavioral: Flywheel Inertial Training; Flywheel inertial training was performed twice weekly for 10 weeks in addition to regular Olympic weightlifting training. The program included lower-limb and trunk exercises such as squats, split squats, Romanian deadlifts, pulling variations, and core stabilization exercises. The training emphasized eccentric overload and progressive resistance to enhance power production and movement control.; Other Names: Flywheel resistance training; eccentric overload training; Behavioral: Traditional Weightlifting Training; Participants performed conventional Olympic weightlifting training including snatch and clean and jerk technique practice, squats, pulling exercises, strength exercises, mobility exercises, and general physical preparation according to the regular training program.
Active Comparator: Control Group (Traditional Weightlifting Training); Participants in this group continued their regular Olympic weightlifting training program only, which included snatch and clean technique practice, strength exercises, pulling derivatives, squats, mobility work, and general physical preparation, without any additional flywheel training.	Behavioral: Traditional Weightlifting Training; Participants performed conventional Olympic weightlifting training including snatch and clean and jerk technique practice, squats, pulling exercises, strength exercises, mobility exercises, and general physical preparation according to the regular training program.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Snatch Performance	Snatch performance was assessed as the best successful snatch lift completed by each participant according to technical criteria. The unit of measurement was kilograms (kg). The outcome was analyzed as the change in kilograms from baseline to 10 weeks.	Baseline and 10 weeks post-intervention
Clean Lift Performance	Clean lift performance was assessed as the best successful clean lift completed by each participant without performing the jerk phase. The unit of measurement was kilograms (kg). The outcome was analyzed as the change in kilograms from baseline to 10 weeks.	Baseline and 10 weeks post-intervention
Countermovement Jump Height	Countermovement jump height was measured to assess lower-limb explosive power. The unit of measurement was centimeters (cm). The outcome was analyzed as the change in centimeters from baseline to 10 weeks.	Baseline and 10 weeks post-intervention
Trunk Inclination Angle During Snatch Receiving Position	Trunk inclination angle was measured during the lowest stable snatch receiving position using video-based kinematic analysis. The angle was measured from the vertical reference line passing through the hip joint. The unit of measurement was degrees (°). The outcome was analyzed as the change in degrees from baseline to 10 weeks. A lower angle indicates a more upright trunk position.	Baseline and 10 weeks post-intervention

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Squat Jump Height	Squat jump height was measured to assess concentric lower-limb power. The unit of measurement was centimeters (cm). The outcome was analyzed as the change in centimeters from baseline to 10 weeks.	Baseline and 10 weeks post-intervention
Standing Long Jump Distance	Standing long jump distance was measured to assess horizontal lower-limb explosive power. The unit of measurement was centimeters (cm). The outcome was analyzed as the change in centimeters from baseline to 10 weeks.	Baseline and 10 weeks post-intervention
Trunk Inclination Angle During Clean Receiving Position	Trunk inclination angle was measured during the lowest stable clean receiving position using video-based kinematic analysis. The angle was measured from the vertical reference line passing through the hip joint. The unit of measurement was degrees (°). The outcome was analyzed as the change in degrees from baseline to 10 weeks. A lower angle indicates a more upright trunk position.	Baseline and 10 weeks post-intervention
Total Weightlifting Performance	Total weightlifting performance was calculated as the sum of the best successful snatch lift and the best successful clean lift without jerk. The unit of measurement was kilograms (kg). The outcome was analyzed as the change in kilograms from baseline to 10 weeks.	Baseline and 10 weeks post-intervention
Technical Error Frequency During Snatch and Clean Attempts	Technical-error frequency was calculated from video analysis by counting the total number of observed technical errors during selected snatch and clean attempts. The coded errors included excessive trunk inclination, forward or backward jump during receiving, unstable receiving position, loss of balance during recovery, and visible bar path deviation. The unit of measurement was number of errors. The outcome was analyzed as the change in number of errors from baseline to 10 weeks.	Baseline and 10 weeks post-intervention

Collaborators and Investigators

• Sponsor: New Damietta University Hospital
• Investigators: Principal Investigator: Ahmed Hassan, PhD, Faculty of Sports Science, Damietta University

Study record dates

Study Major Dates

• Study Start (Actual): December 20, 2025
• Primary Completion (Actual): February 27, 2026
• Study Completion (Actual): February 27, 2026

Study Registration Dates

• First Submitted: May 22, 2026
• First Submitted That Met QC Criteria: May 28, 2026
• First Posted (Actual): June 3, 2026

Study Record Updates

• Last Update Posted (Actual): June 3, 2026
• Last Update Submitted That Met QC Criteria: May 28, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: DU-FLY-2026

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Individual participant data (IPD) collected in this study will include anthropometric data, performance measures (snatch, clean, jump tests), trunk kinematic variables, and technical error scores. De-identified data will be shared with qualified researchers upon reasonable request for secondary analysis.
• IPD Sharing Time Frame: Data will become available after publication of the primary results and will remain accessible for a period of 5 years following publication.
• IPD Sharing Access Criteria: Access to the de-identified dataset will be granted upon reasonable request to the principal investigator. Requests must include a brief research proposal and will be evaluated for scientific merit and ethical compliance.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF; ANALYTIC_CODE

Study Data/Documents

1. Individual Participant Data Set
   Information identifier: OSF Registry: bc4mp
   Information comments: De-identified individual participant data (IPD) will be available upon reasonable request to the principal investigator after publication. Access is restricted to academic research purposes and subject to ethical approval where required. Supporting materials including study protocol, statistical analysis plan, and analytic code are available via the Open Science Framework (OSF) registry.

Drug and device information, study documents

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