Save
Long-Axis Rotational Training Improves Lower Extremity Neuromuscular Control During Forward Single Leg Drop Jump Landing and Stabilization
Author(s):
Nyland J. (United States of America)
,
Nyland J. (United States of America)
Affiliations:
Krupp R.
,
Krupp R.
Affiliations:
Givens J.
,
Givens J.
Affiliations:
Caborn D.
Caborn D.
Affiliations:
ESSKA Academy. Nyland J. 05/09/18; 209291; P02-244 Topic: Biomechanics
Dr. John Nyland
Dr. John Nyland
This content is reserved for ESSKA members. Login or become a member here

You can access free non-premium educational content on the ESSKA Academy Portal by registering for free as 'ESSKA Academy User' here
Abstract
Discussion Forum (0)
Rate & Comment (0)
Objectives: Improved lower extremity neuromuscular control during forward single leg drop jump landing and stabilization (FSLDJLS) may reduce non-contact knee injuries. This prospective randomized, controlled study evaluated the efficacy of long-axis rotational training for improving lower extremity neuromuscular control during FSLDJLS. Previous studies have supported training efficacy for single leg jumping [1], lateral hopping [2], and kicking [3] maneuvers. The hypothesis was that subjects who performed long-axis rotational training would display improved FSLDJLS lower extremity neuromuscular control compared to an untrained control group.

Methods: Thirty-six healthy athletes (24 ± 5 years of age) were randomly assigned to groups of 18 subjects (9 women, 9 men/group). The experimental group trained for nine, 20 min sessions over 3-4 weeks. Both groups continued regular sports without modifying intensity or frequency. All subjects underwent pre- and post-program FSLDJLS testing (20.3 cm step height) as ground reaction force (GRF)(1000 Hz), two-dimensional kinematic (60 Hz), and lower extremity EMG (1000 Hz) data were collected. GRF magnitudes were standardized to bodyweight (N/kg). EMG amplitudes were standardized to maximum volitional isometric contraction values. Muscle activation, GRF and peak lower extremity displacement onset timing were standardized to initial force plate contact. A two-way (group, time) ANOVA was used to evaluate main and mixed effects, and Χ² tests were used to evaluate group neuromuscular activation differences (P ≤ 0.05).

Results: Main effects did not reveal statistically significant differences. Significant group x time interactions were observed. The training group displayed increased dynamic lower extremity stiffness (peak vertical GRF * bodyweight(-1)/peak knee flexion - knee flexion at contact)(P = 0.02), increased gluteus maximus and gluteus medius EMG amplitudes (P ≤ 0.04), and decreased gluteus maximus, gluteus medius, vastus medialis, rectus femoris, and vastus lateralis activation durations (P ≤ 0.04) compared to the control group. More training group subjects also displayed increased post-test gluteus maximus (Χ² = 4.3, P = 0.04) and gluteus medius (Χ² = 4.6, P = 0.03) EMG amplitudes and reduced gluteus maximus (Χ² = 4.3, P = 0.04), gluteus medius (Χ² = 4.3, P = 0.04), vastus medialis (Χ² = 5.8, P = 0.02), rectus femoris (Χ² = 5.8, P = 0.02), vastus lateralis (Χ² = 4.3, P = 0.04) and gastrocnemius (Χ² = 4.3, P = 0.04) EMG activation durations compared to the control group.

Conclusions: Increased training group dynamic lower extremity stiffness, increased hip muscle EMG amplitudes and decreased hip and knee muscle activation durations, with equivalent GRF magnitudes, kinematic displacements and onset timing confirmed improved lower extremity neuromuscular control during FSLDJLS. Long-axis rotational training may reduce the non-contact athletic knee injury risk associated with impaired lower extremity neuromuscular control [1][2][3].

Keywords:
Therapeutic Exercise; Neuromuscular Control; Injury Prevention
Code of conduct/disclaimer available in General Terms & Conditions
Anonymous User Privacy Preferences

Strictly Necessary Cookies (Always Active)

MULTILEARNING platforms and tools hereinafter referred as “MLG SOFTWARE” are provided to you as pure educational platforms/services requiring cookies to operate. In the case of the MLG SOFTWARE, cookies are essential for the Platform to function properly for the provision of education. If these cookies are disabled, a large subset of the functionality provided by the Platform will either be unavailable or cease to work as expected. The MLG SOFTWARE do not capture non-essential activities such as menu items and listings you click on or pages viewed.


Performance Cookies

Performance cookies are used to analyse how visitors use a website in order to provide a better user experience.



Google Analytics is used for user behavior tracking/reporting. Google Analytics works in parallel and independently from MLG’s features. Google Analytics relies on cookies and these cookies can be used by Google to track users across different platforms/services.


Save Settings