Comparison of Architectural and Performance Adaptations of Hip Extension Exercise Under Gravitational or Inertial Loading Conditions

The main objective of this study is to investigate training-induced adaptations in Biceps femoris long head (BFlh) architecture and performance measures such as muscle strength, jumping, and power variables after following 6 weeks of resistance training program with gravitational or inertial hip extension (HE) exercise and a subsequent detraining period, comparing those adaptations with a control group. In addition, this study aims to determine the time course of BFlh architectural adaptations throughout a 6-week training intervention.

Study Overview

• Status: Completed
• Conditions: Injury;Sports
• Intervention / Treatment: Other: Hip extension exercise with inertial load; Other: Hip extension exercise with gravitational load

• Study Type: Interventional
• Enrollment (Actual): 32
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Spain
  • Valencia, Spain
    • Rodrigo Martin-San Agustin

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• at least two years of resistance training experience
• not have any injury, disease or pain that could reduce their maximal effort

Exclusion Criteria:

• history of injury to the lower limbs (including the hamstrings), wrist, or back in the past 18 months

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Gravitational; Hip extension exercise performed under gravitational loading conditions using free-weight equipment during six weeks with two sessions per week.	Other: Hip extension exercise with gravitational load; Hip extension exercise with gravitational load
No Intervention: Control; Participans was advised to continue their regular levels of physical activity but not to perform any lower body resistance training
Experimental: Inertial; Hip extension exercise performed under inertial loading conditions using the EPTE Inertial Concept (Ionclinics SL, L'Alcudia, Spain) during six weeks with two sessions per week. The EPTE Inertial Concept is an inertial device that combines a series of output pulleys and telescopic arms, capable of implementing 6 disks of different weights and radii.	Other: Hip extension exercise with inertial load; Hip extension exercise with inertial load

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Muscle Strength Assessment	Knee flexion was assessed with subjects in prone position performing knee flexor maximal isometrics contractions with a knee angle of approximately 15 degrees. For hip extension, a resisted hip extension was requested with the subjects lying in the prone position with their legs straight. Hip adduction was evaluated in a supine position with the hips at 45º flexion, requesting an maximal isometrics contraction adduction with a resistance in the internal condyle.	Baseline, at the end of the 6 weeks of training and 4 weeks after this (detraining period)
Jump performance	CMJ and SJ, utilizing the MyJump 2 application on an iPad Pro (at 240 frames per second, high-definition video resolution). In the CMJ, participants initiated the jump from a standing position, performed a preparatory movement by bending their knees to 90° flexion, and then jumped upward as high as possible without pausing between movements. Similarly, for the SJ, participants began from a standardized position with knees flexed at 90°, and then jumped as high as possible with hands on their hips. Throughout both tests, participants were instructed to maintain their hands on their hips to minimize lateral and horizontal displacement, ensuring accurate vertical jump measurement.	Baseline, at the end of the 6 weeks of training and 4 weeks after this (detraining period)
Power	Power was calculated in both modalities (i.e., HE gravitational and inertial) as the product of velocity and force. The velocity was calculated using the MuscleLab 4020e linear encoder (Ergotest Technology AS, Porsgrunn, Norway). For gravitational loading (i.e. constant mass), the force was calculated as the product of mass and acceleration. For inertial loading, the force was calculated using a force gauge that was anchored along the rope, between a pulley and the proximal end of the second rope.	Baseline, at the end of the 6 weeks of training and 4 weeks after this (detraining period)
Soreness	Participants were asked "How sore do you feel in your hamstrings?" and rated their soreness on a 10-point Likert Scale (1 = No Soreness, 3 = Minimal Soreness, 5 = Moderate Soreness, 8 = Very Sore, 10 = Extremely Sore)	From session 1 (the beginning of week 1) to session 12 (the end of week 6), at the beginning and end of each session.
Fascicle length	Two-dimensional images of the Biceps femoris long head (BFlh) architecture were captured using B-mode ultrasonography. All imaging was conducted with participants lying prone with their hips and knees in a neutral and fully extended position.Three ultrasound images were taken and stored for analysis through the ImageJ software (National Institutes of Health, USA). The most visible fascicle in each image was used for measurement of fascicle pennation angle (i.e., angle between the fascicle and the intermediate aponeurosis) and estimation of fascicle length using a validated equation: FL = sin (AA + 90°) × MT ÷ sin (180° - (AA + 180° - PA))	Baseline, at weeks 2 and 3 of the intervention, at the end of the 6 weeks of training and 4 weeks after this (detraining period)

Collaborators and Investigators

• Sponsor: University of Valencia
• Investigators: Principal Investigator: Rodrigo Martín-San Agustín, University of Valencia

Study record dates

Study Major Dates

• Study Start (Actual): September 1, 2019
• Primary Completion (Actual): June 30, 2021
• Study Completion (Actual): June 30, 2021

Study Registration Dates

• First Submitted: July 27, 2024
• First Submitted That Met QC Criteria: July 31, 2024
• First Posted (Actual): August 5, 2024

Study Record Updates

• Last Update Posted (Actual): August 9, 2024
• Last Update Submitted That Met QC Criteria: August 5, 2024
• Last Verified: August 1, 2024

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Wounds and Injuries; Athletic Injuries
• Other Study ID Numbers: H1551979435533

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