Elastography, Exercise Training, Healthy, Running, Sport, Ultrasound Imaging
Conditions
Brief summary
The overall goal of this study is to investigate the effects of a 6-week training program between two hamstring exercises-the Romanian deadlift (RDL) and the Nordic hamstring exercise (NHE)-on hamstring strain injury risk factors and sprint performance.
Detailed description
Prior to the intervention, participants will report to the lab on one occasion for baseline assessments. During the baseline visit, a) regional measures of biceps femoris long head fascicle length, pennation angle, muscle thickness, and anatomical cross-sectional area will be determined using ultrasound, b) baseline NHE strength and 3RM for the RDL will be determined, and c) maximal 60 m sprint performance will be measured. 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.
Interventions
DIAGNOSTIC_TESTUltrasound 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.
OTHERHamstring 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.
OTHERMaximal 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.
OTHERRomanian 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.
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.
Sponsors
University of Wisconsin, Madison
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
OTHER
Masking
DOUBLE (Investigator, Outcomes Assessor)
Intervention model description
Each eligible participant will be block randomized (1:1 allocation) to either the RDL or the NHE intervention group
Eligibility
Sex/Gender
ALL
Age
18 Years to 25 Years
Healthy volunteers
Yes
Inclusion criteria
* 18-25 years of age * Have \>6 months experience in resistance training
Exclusion criteria
* History of hamstring strain injury within the last 12 months * 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
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Biceps femoris long head fascicle length | Baseline |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Biceps femoris long head pennation angle | Baseline, Post-intervention (6 weeks), Post 2 week de-training (8 weeks) | — |
| Biceps femoris long head muscle thickness | Baseline, Post-intervention (6 weeks), Post 2 week de-training (8 weeks) | — |
| Biceps femoris long head anatomical cross sectional area | Baseline, Post-intervention (6 weeks), Post 2 week de-training (8 weeks) | — |
| Nordic hamstring exercise (NHE) maximal strength | Baseline, Post-intervention (6 weeks), Post 2 week de-training (8 weeks) | Maximal eccentric force measured by Nordbord device during NHE |
| Maximal 60 m sprint times | Baseline, Post-intervention (6 weeks), Post 2 week de-training (8 weeks) | Fastest 60 m sprint times with interval split times |
| Romanian deadlift (RDL) 3-repetition maximal strength | Baseline, Post-intervention (6 weeks), Post 2 week de-training (8 weeks) | Maximum weight lifted for 3 repetitions during the RDL |
Other
| Measure | Time frame |
|---|---|
| Biceps femoris long head regional shear wave speed | Baseline, Post-intervention (6 weeks), Post 2 week de-training (8 weeks) |
| Inertial measurement unit (IMU)-derived trunk, hip, knee, and ankle kinematics | Baseline, Post-intervention (6 weeks), Post 2 week de-training (8 weeks) |
Countries
United States
Outcome results
None listed