scholarly journals Peak Lower Extremity Landing Kinematics in Dancers and Nondancers

2018 ◽  
Vol 53 (4) ◽  
pp. 379-385 ◽  
Author(s):  
Bethany L. Hansberger ◽  
Shellie Acocello ◽  
Lindsay V. Slater ◽  
Joseph M. Hart ◽  
Jatin P. Ambegaonkar
Keyword(s):  
Injury Risk ◽  
Sagittal Plane ◽  
Frontal Plane ◽  
Acl Injury ◽  
Group Activity ◽  
Dimensional System ◽  
Landing Biomechanics ◽  
Main Effects ◽  
Vertical Jumps ◽  
Jump Landings

Context:  Anterior cruciate ligament (ACL) injuries often occur during jump landings and can have detrimental short-term and long-term functional effects on quality of life. Despite frequently performing jump landings, dancers have lower incidence rates of ACL injury than other jump-landing athletes. Planned versus unplanned activities and footwear may explain differing ACL-injury rates among dancers and nondancers. Still, few researchers have compared landing biomechanics between dancers and nondancers. Objective:  To compare the landing biomechanics of dancers and nondancers during single-legged (SL) drop-vertical jumps. Design:  Cross-sectional study. Setting:  Laboratory. Patients or Other Participants:  A total of 39 healthy participants, 12 female dancers (age = 20.9 ± 1.8 years, height = 166.4 ± 6.7 cm, mass = 63.2 ± 16.4 kg), 14 female nondancers (age = 20.2 ± 0.9 years, height = 168.9 ± 5.0 cm, mass = 61.6 ± 7.7 kg), and 13 male nondancers (age = 22.2 ± 2.7 years, height = 180.6 ± 9.7 cm, mass = 80.8 ± 13.2 kg). Intervention(s):  Participants performed SL–drop-vertical jumps from a 30-cm–high box in a randomized order in 2 activity (planned, unplanned) and 2 footwear (shod, barefoot) conditions while a 3-dimensional system recorded landing biomechanics. Main Outcome Measure(s):  Overall peak sagittal-plane and frontal-plane ankle-, knee-, and hip-joint kinematics (joint angles) were compared across groups using separate multivariate analyses of variance followed by main-effects testing and pairwise-adjusted Bonferroni comparisons as appropriate (P < .05). Results:  No 3-way interactions existed for sagittal-plane or frontal-plane ankle (Wilks λ = 0.85, P = .11 and Wilks λ = 0.96, P = .55, respectively), knee (Wilks λ = 1.00, P = .93 and Wilks λ = 0.94, P = .36, respectively), or hip (Wilks λ = 0.99, P = .88 and Wilks λ = 0.97, P = .62, respectively) kinematics. We observed no group × footwear interactions for sagittal-plane or frontal-plane ankle (Wilks λ = 0.94, P = .43 and Wilks λ = 0.96, P = .55, respectively), knee (Wilks λ = 0.97, P = .60 and Wilks λ = 0.97, P = .66, respectively), or hip (Wilks λ = 0.99, P = .91 and Wilks λ = 1.00, P = .93, respectively) kinematics, and no group × activity interactions were noted for ankle frontal-plane (Wilks λ = 0.92, P = .29) and sagittal- and frontal-plane knee (Wilks λ = 0.99, P = .81 and Wilks λ = 0.98, P = .77, respectively) and hip (Wilks λ = 0.88, P = .13 and Wilks λ = 0.85, P = .08, respectively) kinematics. A group × activity interaction (Wilks λ = 0.76, P = .02) was present for ankle sagittal-plane kinematics. Main-effects testing revealed different ankle frontal-plane angles across groups (F2,28 = 3.78, P = .04), with male nondancers having greater ankle inversion than female nondancers (P = .05). Conclusions:  Irrespective of activity type or footwear, female nondancers landed with similar hip and knee kinematics but greater peak ankle eversion and less peak ankle dorsiflexion (ie, positions associated with greater ACL injury risk). Ankle kinematics may differ between groups due to different landing strategies and training used by dancers. Dancers' training should be examined to determine if it results in a reduced occurrence of biomechanics related to ACL injury during SL landing.

scholarly journals Lower Extremity Energy Absorption and Biomechanics During Landing, Part I: Sagittal-Plane Energy Absorption Analyses

2013 ◽  
Vol 48 (6) ◽  
pp. 748-756 ◽  
Author(s):  
Marc F. Norcross ◽  
Michael D. Lewek ◽  
Darin A. Padua ◽  
Sandra J. Shultz ◽  
Paul S. Weinhold ◽  
...  
Keyword(s):  
Energy Absorption ◽  
Injury Risk ◽  
Sagittal Plane ◽  
Frontal Plane ◽  
Acl Injury ◽  
Knee Extension ◽  
Landing Biomechanics ◽  
Anterior Tibial ◽  
Acl Injury Risk ◽  
Risk Potential

Context: Eccentric muscle actions of the lower extremity absorb kinetic energy during landing. Greater total sagittal-plane energy absorption (EA) during the initial impact phase (INI) of landing has been associated with landing biomechanics considered high risk for anterior cruciate ligament (ACL) injury. We do not know whether groups with different INI EA magnitudes exhibit meaningful differences in ACL-related landing biomechanics and whether INI EA might be useful to identify ACL injury-risk potential. Objective: To compare biomechanical factors associated with noncontact ACL injury among sagittal-plane INI EA groups and to determine whether an association exists between sex and sagittal-plane INI EA group assignment to evaluate the face validity of using sagittal-plane INI EA to identify ACL injury risk. Design: Descriptive laboratory study. Setting: Research laboratory. Patients or Other Participants: A total of 82 (41 men, 41 women; age = 21.0 ± 2.4 years, height = 1.74 ± 0.10 m, mass = 70.3 ± 16.1 kg) healthy, physically active individuals volunteered. Intervention(s): We assessed landing biomechanics using an electromagnetic motion-capture system and force plate during a double-legged jump-landing task. Main Outcome Measure(s): Total INI EA was used to group participants into high, moderate, and low tertiles. Sagittal- and frontal-plane knee kinematics; peak vertical and posterior ground reaction forces (GRFs); anterior tibial shear force; and internal hip extension, knee extension, and knee varus moments were identified and compared across groups using 1-way analyses of variance. We used a χ2 analysis to compare male and female representation in the high and low groups. Results: The high group exhibited greater knee-extension moment and posterior GRFs than both the moderate (P < .05) and low (P < .05) groups and greater anterior tibial shear force than the low group (P < .05). No other group differences were noted. Women were not represented more than men in the high group (χ2 = 1.20, P = .27). Conclusions: Greater sagittal-plane INI EA likely indicates greater ACL loading, but it does not appear to influence frontal-plane biomechanics related to ACL injury. Women were not more likely than men to demonstrate greater INI EA, suggesting that quantification of sagittal-plane INI EA alone is not sufficient to infer ACL injury-risk potential.

scholarly journals DOES BRAIN ACTIVATION DURING FUNCTIONAL MOVEMENT TASKS DIFFERENTIATE BETWEEN GOOD AND BAD MOVERS? AN INTEGRATED NEUROIMAGING ASSESSMENT OF MOTOR CONTROL IN YOUNG ATHLETES

2021 ◽  
Vol 9 (7_suppl3) ◽  
pp. 2325967121S0013
Author(s):  
Manish Anand ◽  
Jed A. Diekfuss ◽  
Dustin R. Grooms ◽  
Alexis B. Slutsky-Ganesh ◽  
Scott Bonnette ◽  
...  
Keyword(s):  
Motor Control ◽  
Range Of Motion ◽  
Brain Function ◽  
Sagittal Plane ◽  
Brain Activity ◽  
Frontal Plane ◽  
Acl Injury ◽  
Timing Error ◽  
Lingual Gyrus ◽  
Increased Activity

Background: Aberrant frontal and sagittal plane knee motor control biomechanics contribute to increased anterior cruciate ligament (ACL) injury risk. Emergent data further indicates alterations in brain function may underlie ACL injury high risk biomechanics and primary injury. However, technical limitations have limited our ability to assess direct linkages between maladaptive biomechanics and brain function. Hypothesis/Purpose: (1) Increased frontal plane knee range of motion would associate with altered brain activity in regions important for sensorimotor control and (2) increased sagittal plane knee motor control timing error would associate with altered activity in sensorimotor control brain regions. Methods: Eighteen female high-school basketball and volleyball players (14.7 ± 1.4 years, 169.5 ± 7 cm, 65.8 ± 20.5 kg) underwent brain functional magnetic resonance imaging (fMRI) while performing a bilateral, combined hip, knee, and ankle flexion/extension movements against resistance (i.e., leg press) Figure 1(a). The participants completed this task to a reference beat of 1.2 Hz during four movement blocks of 30 seconds each interleaved in between 5 rest blocks of 30 seconds each. Concurrent frontal and sagittal plane range of motion (ROM) kinematics were measured using an MRI-compatible single camera motion capture system. Results: Increased frontal plane ROM was associated with increased brain activity in one cluster extending over the occipital fusiform gyrus and lingual gyrus ( p = .003, z > 3.1). Increased sagittal plane motor control timing error was associated with increased brain activity in multiple clusters extending over the occipital cortex (lingual gyrus), frontal cortex, and anterior cingulate cortex ( p < .001, z > 3.1); see Figure 1 (b). Conclusion: The associations of increased knee frontal plane ROM and sagittal plane timing error with increased activity in regions that integrate visuospatial information may be indicative of an increased propensity for knee injury biomechanics that are, in part, driven by reduced spatial awareness and an inability to adequately control knee abduction motion. Increased activation in these regions during movement tasks may underlie an impaired ability to control movements (i.e., less neural efficiency), leading to compromised knee positions during more complex sports scenarios. Increased activity in regions important for cognition/attention associating with motor control timing error further indicates a neurologically inefficient motor control strategy. [Figure: see text]

scholarly journals Do ACL Injury Risk Reduction Exercises Reflect Common Injury Mechanisms? A Scoping Review of Injury Prevention Programs

2021 ◽  
pp. 194173812110379
Author(s):  
Steven L. Dischiavi ◽  
Alexis A Wright ◽  
Rachel A. Heller ◽  
Claire E. Love ◽  
Adam J. Salzman ◽  
...  
Keyword(s):  
Risk Reduction ◽  
Scoping Review ◽  
Injury Risk ◽  
Sagittal Plane ◽  
Cruciate Ligament ◽  
Acl Injury ◽  
Flight Phase ◽  
Targeted Interventions ◽  
Injury Mechanisms ◽  
Acl Injury Risk

Context: Anterior cruciate ligament (ACL) injury risk reduction programs have become increasingly popular. As ACL injuries continue to reflect high incidence rates, the continued optimization of current risk reduction programs, and the exercises contained within them, is warranted. The exercises must evolve to align with new etiology data, but there is concern that the exercises do not fully reflect the complexity of ACL injury mechanisms. It was outside the scope of this review to address each possible inciting event, rather the effort was directed at the elements more closely associated with the end point of movement during the injury mechanism. Objective: To examine if exercises designed to reduce the risk of ACL injury reflect key injury mechanisms: multiplanar movement, single limb stance, trunk and hip dissociative control, and a flight phase. Data Sources: A systematic search was performed using PubMed, Medline, EBSCO (CINAHL), SPORTSDiscus, and PEDro databases. Study Selection: Eligibility criteria were as follows: (1) randomized controlled trials or prospective cohort studies, (2) male and/or female participants of any age, (3) exercises were targeted interventions to prevent ACL/knee injuries, and (4) individual exercises were listed and adequately detailed and excluded if program was unable to be replicated clinically. Study Design: Scoping review. Level of Evidence: Level 4. Data Extraction: A total of 35 studies were included, and 1019 exercises were extracted for analysis. Results: The average Consensus on Exercise Reporting Template score was 11 (range, 0-14). The majority of exercises involved bilateral weightbearing (n = 418 of 1019; 41.0%), followed by single limb (n = 345 of 1019; 33.9%) and nonweightbearing (n = 256 of 1019; 25.1%). Only 20% of exercises incorporated more than 1 plane of movement, and the majority of exercises had sagittal plane dominance. Although 50% of exercises incorporated a flight phase, only half of these also involved single-leg weightbearing. Just 16% of exercises incorporated trunk and hip dissociation, and these were rarely combined with other key exercise elements. Only 13% of exercises challenged more than 2 key elements, and only 1% incorporated all 4 elements (multiplanar movements, single limb stance, trunk and hip dissociation, flight phase) simultaneously. Conclusion: Many risk reduction exercises do not reflect the task-specific elements identified within ACL injury mechanisms. Addressing the underrepresentation of key elements (eg, trunk and hip dissociation, multiplanar movements) may optimize risk reduction in future trials.

Ankle Dorsiflexion Displacement During Landing is Associated With Initial Contact Kinematics but not Joint Displacement

2015 ◽  
Vol 31 (4) ◽  
pp. 205-210 ◽  
Author(s):  
Rebecca L. Begalle ◽  
Meghan C. Walsh ◽  
Melanie L. McGrath ◽  
Michelle C. Boling ◽  
J. Troy Blackburn ◽  
...  
Keyword(s):  
Injury Risk ◽  
Sagittal Plane ◽  
Plantar Flexion ◽  
Three Dimensional ◽  
Contact Angles ◽  
Ankle Dorsiflexion ◽  
Lower Extremity Injury ◽  
Initial Contact ◽  
Joint Displacement ◽  
Jump Landings

The ankle, knee, and hip joints work together in the sagittal plane to absorb landing forces. Reduced sagittal plane motion at the ankle may alter landing strategies at the knee and hip, potentially increasing injury risk; however, no studies have examined the kinematic relationships between the joints during jump landings. Healthy adults (N = 30; 15 male, 15 female) performed jump landings onto a force plate while three-dimensional kinematic data were collected. Joint displacement values were calculated during the loading phase as the difference between peak and initial contact angles. No relationship existed between ankle dorsiflexion displacement during landing and three-dimensional knee and hip displacements. However, less ankle dorsiflexion displacement was associated with landing at initial ground contact with larger hip flexion, hip internal rotation, knee flexion, knee varus, and smaller plantar flexion angles. Findings of the current study suggest that restrictions in ankle motion during landing may contribute to contacting the ground in a more flexed position but continuing through little additional motion to absorb the landing. Transverse plane hip and frontal plane knee positioning may also occur, which are known to increase the risk of lower extremity injury.

scholarly journals Posterior Tibial Slope Angle Correlates With Peak Sagittal and Frontal Plane Knee Joint Loading During Robotic Simulations of Athletic Tasks

2016 ◽  
Vol 44 (7) ◽  
pp. 1762-1770 ◽  
Author(s):  
Nathaniel A. Bates ◽  
Rebecca J. Nesbitt ◽  
Jason T. Shearn ◽  
Gregory D. Myer ◽  
Timothy E. Hewett
Keyword(s):  
Knee Joint ◽  
Slope Angle ◽  
Frontal Plane ◽  
Acl Injury ◽  
Tibial Slope ◽  
Lateral Compartment ◽  
Posterior Tibial Slope ◽  
Posterior Tibial ◽  
Vertical Jumps ◽  
Posterior Tibial Slope Angle

Background: Tibial slope angle is a nonmodifiable risk factor for anterior cruciate ligament (ACL) injury. However, the mechanical role of varying tibial slopes during athletic tasks has yet to be clinically quantified. Purpose: To examine the influence of posterior tibial slope on knee joint loading during controlled, in vitro simulation of the knee joint articulations during athletic tasks. Study Design: Descriptive laboratory study. Methods: A 6 degree of freedom robotic manipulator positionally maneuvered cadaveric knee joints from 12 unique specimens with varying tibial slopes (range, −7.7° to 7.7°) through drop vertical jump and sidestep cutting tasks that were derived from 3-dimensional in vivo motion recordings. Internal knee joint torques and forces were recorded throughout simulation and were linearly correlated with tibial slope. Results: The mean (±SD) posterior tibial slope angle was 2.2° ± 4.3° in the lateral compartment and 2.3° ± 3.3° in the medial compartment. For simulated drop vertical jumps, lateral compartment tibial slope angle expressed moderate, direct correlations with peak internally generated knee adduction ( r = 0.60-0.65), flexion ( r = 0.64-0.66), lateral ( r = 0.57-0.69), and external rotation torques ( r = 0.47-0.72) as well as inverse correlations with peak abduction ( r = −0.42 to −0.61) and internal rotation torques ( r = −0.39 to −0.79). Only frontal plane torques were correlated during sidestep cutting simulations. For simulated drop vertical jumps, medial compartment tibial slope angle expressed moderate, direct correlations with peak internally generated knee flexion torque ( r = 0.64-0.69) and lateral knee force ( r = 0.55-0.74) as well as inverse correlations with peak external torque ( r = −0.34 to −0.67) and medial knee force ( r = −0.58 to −0.59). These moderate correlations were also present during simulated sidestep cutting. Conclusion: The investigation supported the theory that increased posterior tibial slope would lead to greater magnitude knee joint moments, specifically, internally generated knee adduction and flexion torques. Clinical Relevance: The knee torques that positively correlated with increased tibial slope angle in this investigation are associated with heightened risk of ACL injury. Therefore, the present data indicated that a higher posterior tibial slope is correlated to increased knee loads that are associated with heightened risk of ACL injury.

Characterization of Thigh and Shank Segment Angular Velocity During Jump Landing Tasks Commonly Used to Evaluate Risk for ACL Injury

2012 ◽  
Vol 134 (9) ◽  
Author(s):  
Ariel V. Dowling ◽  
Julien Favre ◽  
Thomas P. Andriacchi
Keyword(s):  
Angular Velocity ◽  
Injury Risk ◽  
Sagittal Plane ◽  
Cruciate Ligament ◽  
Acl Injury ◽  
Simple Method ◽  
Jump Landing ◽  
Drop Jumps ◽  
Angular Velocities ◽  
Knee Abduction

The dynamic movements associated with anterior cruciate ligament (ACL) injury during jump landing suggest that limb segment angular velocity can provide important information for understanding the conditions that lead to an injury. Angular velocity measures could provide a quick and simple method of assessing injury risk without the constraints of a laboratory. The objective of this study was to assess the inter-subject variations and the sensitivity of the thigh and shank segment angular velocity in order to determine if these measures could be used to characterize jump landing mechanisms. Additionally, this study tested the correlation between angular velocity and the knee abduction moment. Thirty-six healthy participants (18 male) performed drop jumps with bilateral and unilateral landing. Thigh and shank angular velocities were measured by a wearable inertial-based system, and external knee moments were measured using a marker-based system. Discrete parameters were extracted from the data and compared between systems. For both jumping tasks, the angular velocity curves were well defined movement patterns with high inter-subject similarity in the sagittal plane and moderate to good similarity in the coronal and transverse planes. The angular velocity parameters were also able to detect differences between the two jumping tasks that were consistent across subjects. Furthermore, the coronal angular velocities were significantly correlated with the knee abduction moment (R of 0.28–0.51), which is a strong indicator of ACL injury risk. This study suggested that the thigh and shank angular velocities, which describe the angular dynamics of the movement, should be considered in future studies about ACL injury mechanisms.

scholarly journals Lower Extremity Landing Biomechanics in Both Sexes After a Functional Exercise Protocol

2015 ◽  
Vol 50 (9) ◽  
pp. 914-920 ◽  
Author(s):  
Caroline A. Wesley ◽  
Patricia A. Aronson ◽  
Carrie L. Docherty
Keyword(s):  
Sex Differences ◽  
Injury Risk ◽  
Female Athletes ◽  
Cruciate Ligament ◽  
Movement Analysis ◽  
Acl Injury ◽  
Analysis Tool ◽  
Exercise Protocol ◽  
Cross Sectional ◽  
Landing Biomechanics

Context Sex differences in landing biomechanics play a role in increased rates of anterior cruciate ligament (ACL) injuries in female athletes. Exercising to various states of fatigue may negatively affect landing mechanics, resulting in a higher injury risk, but research is inconclusive regarding sex differences in response to fatigue. Objective To use the Landing Error Scoring System (LESS), a valid clinical movement-analysis tool, to determine the effects of exercise on the landing biomechanics of males and females. Design Cross-sectional study. Setting University laboratory. Patients or Other Participants Thirty-six (18 men, 18 women) healthy college-aged athletes (members of varsity, club, or intramural teams) with no history of ACL injury or prior participation in an ACL injury-prevention program. Intervention(s) Participants were videotaped performing 3 jump-landing trials before and after performance of a functional, sportlike exercise protocol consisting of repetitive sprinting, jumping, and cutting tasks. Main Outcome Measure(s) Landing technique was evaluated using the LESS. A higher LESS score indicates more errors. The mean of the 3 LESS scores in each condition (pre-exercise and postexercise) was used for statistical analysis. Results Women scored higher on the LESS (6.3 ± 1.9) than men (5.0 ± 2.3) regardless of time (P = .04). Postexercise scores (6.3 ± 2.1) were higher than preexercise scores (5.0 ± 2.1) for both sexes (P = .01), but women were not affected to a greater degree than men (P = .62). Conclusions As evidenced by their higher LESS scores, females demonstrated more errors in landing technique than males, which may contribute to their increased rate of ACL injury. Both sexes displayed poor technique after the exercise protocol, which may indicate that participants experience a higher risk of ACL injury in the presence of fatigue.

scholarly journals Sagittal and Frontal Plane Knee Angular Jerk Effects During Prolonged Load Carriage

2020 ◽  
Author(s):  
Samantha M. Krammer
Keyword(s):  
Motion Capture ◽  
Repeated Measures ◽  
Injury Risk ◽  
Sagittal Plane ◽  
Frontal Plane ◽  
Musculoskeletal Injury ◽  
Load Carriage ◽  
Knee Motion ◽  
Effective Measure ◽  
Knee Jerk

Introduction: Musculoskeletal injuries are a costly military problem that routinely occur during training. Quantifying smoothness of knee motion, or angular knee jerk, may be an effective measure to monitor injury risk during training, but to date, the effects of body borne load and prolonged locomotion on angular knee jerk are unknown. Purpose: This study sought to quantify angular knee jerk for frontal and sagittal plane motion during prolonged load carriage. Methods: Eighteen participants had peak and cost of angular jerk for frontal and sagittal plane knee motion quantified while they walked (1.3 m/s) 60-minutes with three body borne loads (0, 15, and 30 kg). Statistical Analysis: Peak and cost of angular jerk for sagittal and frontal plane knee motion of stance phase (0 % - 100%) were derived from motion capture and IMU data and submitted to a repeated measures linear model to test the main effects and interaction of load (0, 15, and 30 kg) and time (0, 15, 30, 45, and 60 min.). Two one sided t-tests (TOSTs) were used to compare the motion capture- and IMU-derived measures of angular jerk for sagittal and frontal plane knee motion. Results: For the motion capture-derived jerk measures, body borne load increased peak and cost of angular jerk for sagittal (p < 0.001, p < 0.001) and frontal (p < 0.001, p < 0.001) plane knee motion, while time increased jerk cost (p = 0.001) of frontal plane knee motion. While the IMU-derived jerk measures exhibited similar increases in peak and cost of angular jerk for sagittal (p < 0.001, p < 0.001) and frontal (p = 0.027, p < 0.001) plane knee motion with addition of load, and in cost (p = 0.015) of angular jerk for frontal plane knee motion with time, they were not statistically equivalent to motion-capture derived measures (p > 0.05). Conclusion: Prolonged load carriage may lead to jerkier knee motion and increased knee musculoskeletal injury risk. Specifically, the jerkier knee motions exhibited with the addition of body borne load and longer walking time may increase the joint loading that leads to greater knee musculoskeletal injury risk.

scholarly journals Associations Among Eccentric Hamstrings Strength, Hamstrings Stiffness, and Jump-Landing Biomechanics

2020 ◽  
Vol 55 (7) ◽  
pp. 717-723 ◽  
Author(s):  
Derek R. Dewig ◽  
Jonathan S. Goodwin ◽  
Brian G. Pietrosimone ◽  
J. Troy Blackburn
Keyword(s):  
Ground Reaction Force ◽  
Injury Risk ◽  
Reaction Force ◽  
Acl Injury ◽  
Ground Contact ◽  
Vertical Ground Reaction Force ◽  
Landing Biomechanics ◽  
Peak Knee ◽  
Acl Injury Risk ◽  
Vertical Ground

Context Anterior cruciate ligament (ACL) injury risk can be assessed from landing biomechanics. Greater hamstrings stiffness is associated with a landing-biomechanics profile consistent with less ACL loading but is difficult to assess in the clinical setting. Eccentric hamstrings strength can be easily evaluated by clinicians and may provide a surrogate measure for hamstrings stiffness. Objective To examine associations among eccentric hamstrings strength, hamstrings stiffness, and landing biomechanics linked to ACL injury risk. Design Cross-sectional study. Setting Research laboratory. Patients or Other Participants A total of 34 uninjured, physically active participants (22 women, 12 men; age = 20.2 ± 1.6 years, height = 171.5 ± 9.7 cm, mass = 67.1 ± 12.7 kg). Intervention(s) We collected eccentric hamstrings strength, active hamstrings stiffness, and double- and single-legged landing biomechanics during a single session. Main Outcome Measure(s) Bivariate associations were conducted between eccentric hamstrings strength and hamstrings stiffness, vertical ground reaction force, internal knee-extension moment, internal knee-varus moment, anterior tibial shear force, knee sagittal-plane angle at initial ground contact, peak knee-flexion angle, knee frontal-plane angle at initial ground contact, peak knee-valgus angle, and knee-flexion displacement using Pearson product moment correlations or Spearman rank-order correlations. Results We observed no association between hamstrings stiffness and eccentric hamstrings strength (r = 0.029, P = .44). We also found no association between hamstrings stiffness and landing biomechanics. However, greater peak eccentric strength was associated with less vertical ground reaction force in both the double-legged (r = −0.331, P = .03) and single-legged (r = −0.418, P = .01) landing conditions and with less internal knee-varus moment in the single-legged landing condition (r = −0.326, P = .04). Conclusions Eccentric hamstrings strength was associated with less vertical ground reaction force during both landing tasks and less internal knee-varus moment during the single-legged landing but was not an acceptable clinical estimate of active hamstrings stiffness.

scholarly journals Reflecting on side-cutting variability on ACL injury risk: A case study

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Muhammad Hamdan ◽  
Raja Mohammed Firhad Raja Azidin
Keyword(s):  
Injury Risk ◽  
Sagittal Plane ◽  
Cruciate Ligament ◽  
Acl Injury ◽  
Ligament Injury ◽  
Task Execution ◽  
Soccer Match ◽  
Laboratory Session ◽  
Increased Risk

This case study aims to discuss a proposal for identifying anterior cruciate ligament injury (ACL) risk by observing the variability of side cutting kinematics with respect to the development of fatigue. One participant (n=1) sustained an ACL injury while performing a side-cutting task during the latter stages of a soccer match a few months after a recorded laboratory session. Data from his laboratory session was then compared to matched samples of seventeen healthy, uninjured participants (n=17). The injured participant was found to have performed his side-cutting task with a lower deviation than mean variability right before the later stages of the second half of simulated soccer match-play. Over time, the participant performed side-cutting tasks with increased variability in sagittal plane kinematics, suggesting that compensatory actions may have been implemented to facilitate the task execution. This elevated variability may be indicative of an increased risk of ACL injury. The further prospective investigation is warranted to gain a deeper understanding of how variabilities may play a role in task execution performance with respect to injury mechanisms.

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