. 4 , 10 , 11 Studies have shown that single-leg landings are more likely to result in increased ACL loading than double-leg landings because of greater impact forces and decreased knee flexion angles during the landing phase. 10 – 13 In addition, some studies found that females demonstrated lower
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Prelanding Knee Kinematics and Landing Kinetics During Single-Leg and Double-Leg Landings in Male and Female Recreational Athletes
Ling Li, Yu Song, Maddy Jenkins, and Boyi Dai
Muscular Coordination of Single-Leg Hop Landing in Uninjured and Anterior Cruciate Ligament-Reconstructed Individuals
Prasanna Sritharan, Luke G. Perraton, Mario A. Munoz, Peter Pivonka, and Adam L. Bryant
. 2 Increasing the rate of postsurgery participation in sport represents a challenge to rehabilitation research and may be garnered through improvements in clinical assessment. The single-leg hop for distance is a well-studied and routinely employed task in the functional evaluation of ACLR
Comparison of 5 Normalization Methods for Knee Joint Moments in the Single-Leg Squat
Steven M. Hirsch, Christopher J. Chapman, David M. Frost, and Tyson A.C. Beach
assessed using NJM about the mediolateral (NJM-ML) and anteroposterior (NJM-AP) axes of the knee joint during a single-leg squat movement, using data extracted from a published study that were collected for a different purpose. 13 It was hypothesized that dividing NJM by mass × height and mass × leg
Subsequent Jumping Increases the Knee and Hip Abduction Moment, Trunk Lateral Tilt, and Trunk Rotation Motion During Single-Leg Landing in Female Individuals
Masato Chijimatsu, Tomoya Ishida, Masanori Yamanaka, Shohei Taniguchi, Ryo Ueno, Ryohei Ikuta, Mina Samukawa, Takumi Ino, Satoshi Kasahara, and Harukazu Tohyama
reduced to minimize the risk of ACL injuries, especially in female athletes. Double-/single-leg drop landing (SDL) and drop vertical jumping (SDVJ) are common landing tasks used to evaluate the knee abduction moment. 8 , 11 – 14 The presence or absence of a subsequent jump after landing leads to
Variables Associated With Knee Valgus in Male Professional Soccer Players During a Single-Leg Vertical Landing Task
Matheus Vianna, Leonardo Metsavaht, Eliane Guadagnin, Carlos Eduardo Franciozi, Marcus Luzo, Marcio Tannure, and Gustavo Leporace
programs to suit the unique needs of this population. Therefore, this study aimed to investigate the correlation between knee valgus and lateral trunk inclination, hip adduction, and internal rotation angles during a continuous single-leg vertical landing task in professional male soccer athletes as well
Effect of Fatigue on Single-Leg Hop Landing Biomechanics
Karl F. Orishimo and Ian J. Kremenic
The objective of this study was to measure adaptations in landing strategy during single-leg hops following thigh muscle fatigue. Kinetic, kinematic, and electromyographic data were recorded as thirteen healthy male subjects performed a single-leg hop in both the unfatigued and fatigued states. To sufficiently fatigue the thigh muscles, subjects performed at least two sets of 50 step-ups. Fatigue was assessed by measuring horizontal hopping ability following the protocol. Joint motion and loading, as well as muscle activation patterns, were compared between fatigued and unfatigued conditions. Fatigue significantly increased knee motion (p = 0.012) and shifted the ankle into a more dorsiflexed position (p = 0.029). Hip flexion was also reduced following fatigue (p = 0.042). Peak extension moment tended to decrease at the knee and increase at the ankle and hip (p = 0.014). Ankle plantar flexion moment at the time of peak total support moment increased from 0.8 (N⋅m)/kg (SD, 0.6 [N⋅m]/kg) to 1.5 (N⋅m)/kg (SD, 0.8 [N⋅m]/kg) (p = 0.006). Decreased knee moment and increased knee flexion during landings following fatigue indicated that the control of knee motion was compromised despite increased activation of the vastus medialis, vastus lateralis, and rectus femoris (p = 0.014, p = 0.014, and p = 0.017, respectively). Performance at the ankle increased to compensate for weakness in the knee musculature and to maintain lower extremity stability during landing. Investigating the biomechanical adaptations that occur in healthy subjects as a result of muscle fatigue may give insight into the compensatory mechanisms and loading patterns occurring in patients with knee pathology. Changes in single-leg hop landing performance could be used to demonstrate functional improvement in patients due to training or physical therapy.
Optimizing Whole-Body Kinematics During Single-Leg Jump Landing to Reduce Peak Abduction/Adduction and Internal Rotation Knee Moments: Implications for Anterior Cruciate Ligament Injury Risk
Dhruv Gupta, Jeffrey A. Reinbolt, and Cyril J. Donnelly
/adduction and internal rotation knee moments that elevates the ACL load and injury risk more than either in isolation. 16 Therein, it should be the focus of injury-prevention frameworks to reduce both abduction/adduction and internal rotation moments during the weight-acceptance phase of single-leg landing and
Eight-Week Inspiratory Muscle Training Alters Electromyography Activity of the Ankle Muscles During Overhead and Single-Leg Squats: A Randomized Controlled Trial
Behnam Gholami-Borujeni, Ali Yalfani, and Leila Ahmadnezhad
and low-back region diminishes (eg, when one is standing on an unstable surface and implementing overhead and single-leg squats), individuals may rely more heavily on other proprioceptive inputs. 3 This process is known as proprioceptive reweighting, which leads to the greater use of the
Relationship Between Bilateral Differences in Single-Leg Jumps and Asymmetry in Isokinetic Knee Strength
Yuji Kobayashi, Junjiro Kubo, Takeo Matsubayashi, Akifumi Matsuo, Kando Kobayashi, and Naokata Ishii
The aims of the study were to investigate the differences in kinematics and kinetics between the dominant and nondominant leg during single-leg jumps without arm swing, and to determine the relationship between bilateral asymmetry in isokinetic knee strength and the single-leg jump. Isokinetic knee strength and single-leg jump kinematics and kinetics were measured in 11 male participants. The bilateral asymmetry index was calculated for each parameter. For isokinetic knee strength, there were no significant differences between the dominant and nondominant legs. Significant correlations were observed for the bilateral asymmetry index for isokinetic knee strength at 180 degrees per second and the bilateral asymmetry indexes for maximum flexion angle and the mean knee joint torque during the single-leg jumps. In conclusion, the findings of the current study suggest an association between knee strength imbalances and the joint angle, as well as the torque produced in single-leg jumps, although no relationship between knee strength and jump height was observed.
Muscle Synergies During a Single-Leg Drop-Landing in Boys and Girls
Kristof Kipp, Ron Pfeiffer, Michelle Sabick, Chad Harris, Jeanie Sutter, Seth Kuhlman, and Kevin Shea
The purpose of this study was to investigate muscle activation patterns during a landing task in boys and girls through the use of muscle synergies. Electromyographical data from six lower extremity muscles were collected from 11 boys and 16 girls while they performed single-leg drop-landings. Electromyographical data from six leg muscles were rectified, smoothed, and normalized to maximum dynamic muscle activity during landing. Data from 100 ms before to 100 ms after touchdown were submitted to factor analyses to extract muscle synergies along with the associated activation and weighing coefficients. Boys and girls both used three muscle synergies. The activation coefficients of these synergies captured muscle activity during the prelanding, touchdown, and postlanding phases of the single-leg drop-landing. Analysis of the weighing coefficients indicated that within the extracted muscle synergies the girls emphasized activation of the medial hamstring muscle during the prelanding and touchdown synergy whereas boys emphasized activation of the vastus medialis during the postlanding synergy. Although boys and girls use similar muscle synergies during single-leg drop-landings, they differed in which muscles were emphasized within these synergies. The observed differences in aspects related to the muscle synergies during landing may have implications with respect to knee injury risk.
