Injury;Sports
Conditions
Brief summary
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.
Interventions
OTHERHip extension exercise with inertial load
Hip extension exercise with inertial load
OTHERHip extension exercise with gravitational load
Hip extension exercise with gravitational load
Sponsors
University of Valencia
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
DOUBLE (Caregiver, Outcomes Assessor)
Eligibility
Sex/Gender
MALE
Age
18 Years to No maximum
Healthy volunteers
Yes
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Fascicle length | 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) | 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)) |
| Muscle Strength Assessment | Baseline, at the end of the 6 weeks of training and 4 weeks after this (detraining period) | 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. |
| Jump performance | Baseline, at the end of the 6 weeks of training and 4 weeks after this (detraining period) | 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. |
| Power | Baseline, at the end of the 6 weeks of training and 4 weeks after this (detraining period) | 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. |
| Soreness | From session 1 (the beginning of week 1) to session 12 (the end of week 6), at the beginning and end of each session. | 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) |
Countries
Spain
Outcome results
None listed