The purpose of this study is to compare the effects of an intensity-, volume-, and time under tension-matched eccentric hamstring exercise intervention with the Romanian deadlift (RDL) and the Nordic hamstring exercise (NHE) to a sprint-specific training program on hamstring muscle architecture, volume, sprint performance, strength, and power. Participants will be assigned to complete one of the 3 hamstring interventions for 10 weeks.
Prior to the intervention, participants will undergo baseline testing which will include a) ultrasound imaging of the hamstrings muscles for measures of biceps femoris long head fascicle length, pennation angle, muscle thickness, anatomical cross-sectional area, and muscle volume b) passive and active ranges of motion, c) 3 repetition maximum (3RM) RDL strength, d) peak NHE force, e) countermovement jump height, f) broad jump distance, g) Pro Agility change of direction, and h) a 60 m sprint with sprint kinematics assessed via inertial measurement units. Participants will be randomly assigned to either the RDL, NHE, or sprint training group. After randomization, each participant will undergo the intervention program based upon their group allocation. Performance testing and imaging will be repeated mid-intervention, following the intervention, and after 2 weeks of deloading.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
DOUBLE
Enrollment
90
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.
The NHE will be performed with a 6 second eccentric component.
The sprint training program will be performed twice per week with the first day of training focused on shorter distances to focus on acceleration and the second training day focused on maximal velocity. The relative efforts and distances for each training day will mimic a similar prescription to that of the resistance training program.
University of Wisconsin - Madison
Madison, Wisconsin, United States
Change in fascicle length (FL)
Time frame: Baseline to Mid-intervention (6 weeks), Post-intervention (10 weeks), and Post 2 week de-training (12 weeks)
Change in muscle cross-sectional area (CSA)
Time frame: Baseline to Mid-intervention (6 weeks), Post-intervention (10 weeks), and Post 2 week de-training (12 weeks)
Change in muscle volume
Time frame: Baseline to Mid-intervention (6 weeks), Post-intervention (10 weeks), and Post 2 week de-training (12 weeks)
Change in pennation angle (PA)
Time frame: Baseline to Mid-intervention (6 weeks), Post-intervention (10 weeks), and Post 2 week de-training (12 weeks)
Change in eccentric strength
Eccentric hamstring strength of each limb will be assessed during the hamstring exercise.
Time frame: Baseline to Mid-intervention (6 weeks), Post-intervention (10 weeks), and Post 2 week de-training (12 weeks)
Change in inertial measurement units (IMU)-based sprinting biomechanics
Sprinting biomechanics will be assessed using seven IMUs (sacrum, both thighs, both shanks, both feet). Lower extremity joint motions referenced to upright stance will be calculated throughout an on-field sprint and other football drills.
Time frame: Baseline to Mid-intervention (6 weeks), Post-intervention (10 weeks), and Post 2 week de-training (12 weeks)
Change in countermovement jump (CMJ) performance
Time frame: Baseline to Mid-intervention (6 weeks), Post-intervention (10 weeks), and Post 2 week de-training (12 weeks)
Change in standing broad jump (SBJ) performance
Time frame: Baseline to Mid-intervention (6 weeks), Post-intervention (10 weeks), and Post 2 week de-training (12 weeks)
Change in change of direction (CoD) performance
Time frame: Baseline to Mid-intervention (6 weeks), Post-intervention (10 weeks), and Post 2 week de-training (12 weeks)
Change in range of motion (ROM) performance
Time frame: Baseline to Mid-intervention (6 weeks), Post-intervention (10 weeks), and Post 2 week de-training (12 weeks)
Change in hip flexion
Time frame: Baseline to Mid-intervention (6 weeks), Post-intervention (10 weeks), and Post 2 week de-training (12 weeks)
Change in anterior pelvic tilt
Time frame: Baseline to Mid-intervention (6 weeks), Post-intervention (10 weeks), and Post 2 week de-training (12 weeks)
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