Eccentric Training Effects on Hamstrings Structure, Strength, and Sprint Performance
NCT ID: NCT05455346
Last Updated: 2023-12-21
Study Results
The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.
Basic Information
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COMPLETED
NA
32 participants
INTERVENTIONAL
2022-12-02
2023-12-08
Brief Summary
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Detailed Description
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Participants will be randomly assigned to either the RDL or NHE. After randomization, each participant will undergo the 6 week intervention program based upon their group allocation. Exercises will be performed using a 6 second eccentric (i.e., lowering) contraction.
Following the 6 week intervention, participants would return to the lab for post-intervention assessments of regional hamstring morphology and architecture and sprint testing, which would be carried out in the same manner as baseline assessments. Since fascicle length changes are known to return to baseline values within 2 weeks after the cessation of eccentric training, participants will be asked to return to the lab following a 2 week detraining period where final imaging, strength, and sprint performance assessments will be determined.
Conditions
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Study Design
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RANDOMIZED
PARALLEL
OTHER
DOUBLE
Study Groups
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Romanian Deadlift
The training intervention groups will undergo the same program with the only difference being the interventional hamstring exercise. The program will consist of a 2-week acclimatization period followed by 4-weeks of progressive training. The RDL will be performed with a 6 second eccentric component with the athlete returning to the start position with a maximal concentric hip extension.
Ultrasound imaging
Ultrasound B-mode images will be unilaterally collected from the biceps femoris muscle of the dominant limb for each participant using a commercial ultrasound system and linear array transducer. Standardized image locations will correspond to 33%, 50%, and 67% of the thigh length from the ischial tuberosity.
Three repeat longitudinal extended-field-of-view images of the entire biceps femoris muscle will be collected for offline analysis for fascicle length, muscle thickness, and pennation angle. Transverse extended-field-of-view images will be captured at the proximal, mid-belly, and distal locations to determine regional anatomical cross-sectional area of the biceps femoris long head muscle.
To determine changes in tissue stiffness via ultrasound shear wave speed, the same transducer will be placed in the same locations in a longitudinal view. Shear wave maps will be generated by the ultrasound system and shear wave speed measures extracted from the middle of the map.
Hamstring Eccentric Strength Testing
Prior to each test, participants will perform a standardized 5-minute general warm-up followed by a task-specific warm-up including 3 sets of submaximal trials. Load increases (5-20%) will be added for each RDL 3-repetition maximum trial attempt until the participant cannot complete 3 repetitions through the full range of motion using proper technique. A 3-minute rest will be administered between all warm-up and testing sets to allow for full recovery.
Participants will kneel on a commercial device used to assess maximum eccentric knee flexor strength via uniaxial load cells with their ankles secured into fixed hooks. Participants will slowly lower their torso to the ground with arms crossed across their chest and without bending at the hips or spine. The maximal test will consist of 1 set of 3 maximal repetitions. If participants can control lower themselves to the ground, then they will hold barbell plates (5-10 lb increments) across their chest while performing the NHE.
Maximal 60 m Sprint
Following a standardized warm-up, inertial measurement units (IMUs) will be placed on the sternum, sacrum, and bilaterally on the thighs, legs, and foot. Each participant will perform a total of 3 maximal 60 m sprints from a standing position with 1.5-3 min rest in between each trial to minimize the effects of fatigue.
Romanian Deadlift
The RDL intervention will be performed twice per week for 6 weeks. Participants will hinge at the hips lowering the bar to just below their patella before reversing the movement. The RDL will be performed with a 6 second eccentric component and returning to the start position with a maximal concentric hip extension.
Nordic Hamstring Exercise
The training intervention groups will undergo the same program with the only difference being the interventional hamstring exercise. The program will consist of a 2-week acclimatization period followed by 4-weeks of progressive training. During the acclimatization period, the relative intensity will be lower compared to the 4-week progressive training to ensure each participant performs the exercise with proper technique. During the subsequent progressive training weeks, the participants will perform the NHE without the bands.
Ultrasound imaging
Ultrasound B-mode images will be unilaterally collected from the biceps femoris muscle of the dominant limb for each participant using a commercial ultrasound system and linear array transducer. Standardized image locations will correspond to 33%, 50%, and 67% of the thigh length from the ischial tuberosity.
Three repeat longitudinal extended-field-of-view images of the entire biceps femoris muscle will be collected for offline analysis for fascicle length, muscle thickness, and pennation angle. Transverse extended-field-of-view images will be captured at the proximal, mid-belly, and distal locations to determine regional anatomical cross-sectional area of the biceps femoris long head muscle.
To determine changes in tissue stiffness via ultrasound shear wave speed, the same transducer will be placed in the same locations in a longitudinal view. Shear wave maps will be generated by the ultrasound system and shear wave speed measures extracted from the middle of the map.
Hamstring Eccentric Strength Testing
Prior to each test, participants will perform a standardized 5-minute general warm-up followed by a task-specific warm-up including 3 sets of submaximal trials. Load increases (5-20%) will be added for each RDL 3-repetition maximum trial attempt until the participant cannot complete 3 repetitions through the full range of motion using proper technique. A 3-minute rest will be administered between all warm-up and testing sets to allow for full recovery.
Participants will kneel on a commercial device used to assess maximum eccentric knee flexor strength via uniaxial load cells with their ankles secured into fixed hooks. Participants will slowly lower their torso to the ground with arms crossed across their chest and without bending at the hips or spine. The maximal test will consist of 1 set of 3 maximal repetitions. If participants can control lower themselves to the ground, then they will hold barbell plates (5-10 lb increments) across their chest while performing the NHE.
Maximal 60 m Sprint
Following a standardized warm-up, inertial measurement units (IMUs) will be placed on the sternum, sacrum, and bilaterally on the thighs, legs, and foot. Each participant will perform a total of 3 maximal 60 m sprints from a standing position with 1.5-3 min rest in between each trial to minimize the effects of fatigue.
Nordic hamstring exercise
The NHE will be performed twice per week for 6 weeks. Participants will be instructed to maintain their ankles in a dorsiflexed position, lower themselves as close to the ground as possible at a constant and controlled speed while maintaining a neutral position of the hips and trunk, and to cross their arms in front of their chest.
Interventions
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Ultrasound imaging
Ultrasound B-mode images will be unilaterally collected from the biceps femoris muscle of the dominant limb for each participant using a commercial ultrasound system and linear array transducer. Standardized image locations will correspond to 33%, 50%, and 67% of the thigh length from the ischial tuberosity.
Three repeat longitudinal extended-field-of-view images of the entire biceps femoris muscle will be collected for offline analysis for fascicle length, muscle thickness, and pennation angle. Transverse extended-field-of-view images will be captured at the proximal, mid-belly, and distal locations to determine regional anatomical cross-sectional area of the biceps femoris long head muscle.
To determine changes in tissue stiffness via ultrasound shear wave speed, the same transducer will be placed in the same locations in a longitudinal view. Shear wave maps will be generated by the ultrasound system and shear wave speed measures extracted from the middle of the map.
Hamstring Eccentric Strength Testing
Prior to each test, participants will perform a standardized 5-minute general warm-up followed by a task-specific warm-up including 3 sets of submaximal trials. Load increases (5-20%) will be added for each RDL 3-repetition maximum trial attempt until the participant cannot complete 3 repetitions through the full range of motion using proper technique. A 3-minute rest will be administered between all warm-up and testing sets to allow for full recovery.
Participants will kneel on a commercial device used to assess maximum eccentric knee flexor strength via uniaxial load cells with their ankles secured into fixed hooks. Participants will slowly lower their torso to the ground with arms crossed across their chest and without bending at the hips or spine. The maximal test will consist of 1 set of 3 maximal repetitions. If participants can control lower themselves to the ground, then they will hold barbell plates (5-10 lb increments) across their chest while performing the NHE.
Maximal 60 m Sprint
Following a standardized warm-up, inertial measurement units (IMUs) will be placed on the sternum, sacrum, and bilaterally on the thighs, legs, and foot. Each participant will perform a total of 3 maximal 60 m sprints from a standing position with 1.5-3 min rest in between each trial to minimize the effects of fatigue.
Romanian Deadlift
The RDL intervention will be performed twice per week for 6 weeks. Participants will hinge at the hips lowering the bar to just below their patella before reversing the movement. The RDL will be performed with a 6 second eccentric component and returning to the start position with a maximal concentric hip extension.
Nordic hamstring exercise
The NHE will be performed twice per week for 6 weeks. Participants will be instructed to maintain their ankles in a dorsiflexed position, lower themselves as close to the ground as possible at a constant and controlled speed while maintaining a neutral position of the hips and trunk, and to cross their arms in front of their chest.
Other Intervention Names
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Eligibility Criteria
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Inclusion Criteria
* Have \>6 months experience in resistance training
Exclusion Criteria
* History of lower extremity surgery
* Current musculoskeletal injury to the lower extremity
* Females who are currently pregnant
* Individuals who indicate they are unwilling to refrain from novel outside training activities
* Individuals who do not complete 75% (9 out of 12) of the training sessions
18 Years
25 Years
ALL
Yes
Sponsors
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University of Wisconsin, Madison
OTHER
Responsible Party
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Principal Investigators
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Scott K Crawford, PhD
Role: PRINCIPAL_INVESTIGATOR
University of Wisconsin, Madison
Locations
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University of Wisconsin
Madison, Wisconsin, United States
Countries
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References
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Crawford SK, Sandberg C, Vlisides J, Thompson Q, Mosiman SJ, Heiderscheit BC, Hickey JT. Hamstrings Muscle Architecture and Morphology Following 6 wk of an Eccentrically Biased Romanian Deadlift or Nordic Hamstring Exercise Intervention. Med Sci Sports Exerc. 2025 Aug 1;57(8):1799-1809. doi: 10.1249/MSS.0000000000003701. Epub 2025 May 14.
Crawford SK, Hickey J, Vlisides J, Chambers JS, Mosiman SJ, Heiderscheit BC. The effects of hip- vs. knee-dominant hamstring exercise on biceps femoris morphology, strength, and sprint performance: a randomized intervention trial protocol. BMC Sports Sci Med Rehabil. 2023 Jun 26;15(1):72. doi: 10.1186/s13102-023-00680-w.
Other Identifiers
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Protocol Version 2/27/2023
Identifier Type: OTHER
Identifier Source: secondary_id
A176000
Identifier Type: OTHER
Identifier Source: secondary_id
2022-0763
Identifier Type: -
Identifier Source: org_study_id