Comparison of Center of Pressure and Kinematic Differences in Grand Plié With and Without the Barre

The purpose of this study was to determine what differences exist when performing grand plié with and without the barre. Differences in center of pressure (COP) sway, trunk kinematics, and lower extremity kinematics were used in this analysis for both first (P1) and fifth positions (P5). It was hypothesized that use of the barre would result in decreased COP sway, but increased asymmetries in trunk and lower extremity kinematics would be seen compared with the same movements performed without the barre in both positions. Sixteen collegiate dancers (1 male, 15 female) performed three trials of grand plié in P1 and P5 (right leg crossed in front) with or without the barre, for a total of 12 trials. For the barre condition (BC), participants demonstrated less time to complete grand plié, slightly less depth in grand plié, and decreased anterior-posterior (AP) sway compared to the without barre condition (WBC). The BC condition showed increased peak left trunk rotation, right knee flexion, decreased right and left peak hip flexion, and increased right hip abduction in both P1 and P5. Comparing P1 to P5, there was decreased AP sway, decreased peak left trunk rotation, decreased peak right and left hip flexion, increased left hip abduction, and decreased right knee flexion in both BC and WBC conditions. For the BC, there was increased right hip abduction in P1 compared to P5. Our results indicate that while use of the barre provides proprioceptive information, which helps dancers to control balance and learn a motor control strategy, grand plié should also be taught without the barre to challenge the dancer's balance control with different movement patterns in space.

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Test Re-test Reliability of Single and Multijoint Strength Properties in Female Australian Footballers

Sports Medicine - Open ◽

10.1186/s40798-020-00292-5 ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Daniel Kadlec ◽

Matthew J. Jordan ◽

Leanne Snyder ◽

Jacqueline Alderson ◽

Sophia Nimphius

Keyword(s):

Knee Flexion ◽

Intraclass Correlation ◽

Strength Properties ◽

Peak Force ◽

Test Reliability ◽

Leg Extension ◽

Hip Abduction ◽

Hip Flexion ◽

Voluntary Contractions ◽

Trunk Position

Abstract Purpose To examine the test re-test reliability of isometric maximal voluntary contractions (MVC) of hip adduction (ADDISO), hip abduction (ABDISO), and multijoint leg extension (SQUATISO) in sub-elite female Australian footballers. Methods Data were collected from 24 sub-elite female Australian footballers (age 22.6 ± 4.5 years; height 169.4 ± 5.5 cm; body mass 66.6 ± 8.0 kg; 4.5 ± 4.4 years sport-specific training; 2.5 ± 2.0 years unstructured resistance training) from the same club on two non-consecutive days. Participants performed three isometric MVCs of ADDISO, ABDISO, and SQUATISO. The SQUATISO was performed at 140° knee flexion with a vertical trunk position and ADDISO and ABDISO measures were performed in a supine position at 60° of knee flexion and 60° hip flexion. Reliability was assessed using paired t tests and the intraclass correlation coefficient (ICC) with 95% confidence intervals (CI), typical error (TE), and coefficient of variation (CV%) with 95% CI. Results SQUATISO peak force (ICC .95; CV% 4.1), ABDISO for left, right, and sum (ICC .90–.92; CV% 5.0–5.7), and ADDISO for left, right, and sum (ICC .86–.91; CV% 6.2–6.9) were deemed acceptably reliable based on predetermined criteria (ICC ≥ .8 and CV% ≤ 10). Conclusion SQUATISO, ABDISO, and ADDISO tests demonstrated acceptable reliability for the assessment of peak force in sub-elite female Australian footballers, suggesting these assessments are suitable for muscle strength testing and monitoring adaptations to training.

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Lower Extremity Neuromuscular Control Immediately After Fatiguing Hip-Abduction Exercise

Journal of Athletic Training ◽

10.4085/1062-6050-46.6.607 ◽

2011 ◽

Vol 46 (6) ◽

pp. 607-614 ◽

Cited By ~ 14

Author(s):

Kelly L. McMullen ◽

Nicole L. Cosby ◽

Jay Hertel ◽

Christopher D. Ingersoll ◽

Joseph M. Hart

Keyword(s):

Lower Extremity ◽

Postural Control ◽

Center Of Pressure ◽

Neuromuscular Control ◽

Lower Extremity Injury ◽

Median Frequency ◽

Men And Women ◽

Hip Abduction ◽

Quality Of Movement

Context: Fatigue of the gluteus medius (GMed) muscle might be associated with decreases in postural control due to insufficient pelvic stabilization. Men and women might have different muscular recruitment patterns in response to GMed fatigue. Objective: To compare postural control and quality of movement between men and women after a fatiguing hip-abduction exercise. Design: Descriptive laboratory study. Setting: Controlled laboratory. Patients or Other Participants: Eighteen men (age = 22 ± 3.64 years, height = 183.37 ± 8.30 cm, mass = 87.02 ±12.53 kg) and 18 women (age = 22 ± 3.14, height = 167.65 ± 5.80 cm, mass = 66.64 ± 10.49 kg) with no history of low back or lower extremity injury participated in our study. Intervention(s): Participants followed a fatiguing protocol that involved a side-lying hip-abduction exercise performed until a 15% shift in electromyographic median frequency of the GMed was reached. Main Outcome Measure(s): Baseline and postfatigue measurements of single-leg static balance, dynamic balance, and quality of movement assessed with center-of-pressure measurements, the Star Excursion Balance Test, and lateral step-down test, respectively, were recorded for the dominant lower extremity (as identified by the participant). Results: We observed no differences in balance deficits between sexes (P > .05); however, we found main effects for time with all of our postfatigue outcome measures (P ≤ .05). Conclusions: Our findings suggest that postural control and quality of movement were affected negatively after a GMed-fatiguing exercise. At similar levels of local muscle fatigue, men and women had similar measurements of postural control.

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Development of an on-field injury screening test using wearable sensor technology

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967120s00513 ◽

2020 ◽

Vol 8 (9_suppl7) ◽

pp. 2325967120S0051

Author(s):

Pinar Melodi Caliskan ◽

Anne Benjaminse ◽

Alli Gokeler

Keyword(s):

Knee Flexion ◽

Motor Coordination ◽

Knee Extension ◽

Ankle Dorsiflexion ◽

Hip Abduction ◽

Knee Abduction ◽

Hip Flexion ◽

Injury Screening ◽

Coordination Patterns ◽

Hip Extension

Introduction: Injuries of the anterior cruciate ligament (ACL) commonly occur during complex game situations when the athlete encounters multiple factors such as ball, opponent, field position, and game strategy (Grooms et al., 2018). Many of the current traditional injury screening programs are performed within a predictable, fixed or ‘closed’ environment which do not represent real game situations that require high neurocognitive demands (Dingenen & Gokeler, 2017; Grooms et al., 2018). A complementary approach to lab-based settings is necessary to incorporate the demands of the complex athletic environments. By using wearable sensor technology, we aim to develop an on-field injury screening test in elite youth male soccer players. Investigating the individual differences in motor coordination patterns of the players during sport-specific tasks might enhance our understanding of how ACL injuries occur. Hypotheses: We hypothesized that the motor coordination patterns of the players would be affected when they perform under different conditions manipulated with constraints (task and environmental). Methods: A football-specific test setup was created to analyse the kinematic and performance measures of a group of 17 male youth elite football players aged 15 years (height = 164 ± 9 cm, mass = 50.9± 7.4 kg). The players were grouped into two and measured on two consecutive days. All the players were instructed to complete the test setup (4 conditions, 5 trials) as fast as possible. Condition 1 includes no constraint, condition 2 includes a task constraint (football dummies), condition 3 includes an environmental constraint (stroboscopic glasses) (SENAPTEC, Beaverton, Oregon) and condition 4 includes both task and environmental constraints. 3-D kinematics of the hip, knee, ankle joints were captured using Xsens wearable full-body sensor suits (Xsens, MVN Link version, Enschede, The Netherlands). MATLAB (MATLAB R2019a, The MathWorks Inc., Massachusetts) was used to process and analyse the kinematic data. Data from condition 1 was determined as reference behavior/condition to be compared to other conditions. Kinematic data are presented in attitude vectors (ATV). Results: In total, 81% of the players demonstrated a significant difference (P < 0.05) in angles of hip, knee and ankle joints when performing under different conditions. The percentage of players with increased comparison-based joint movements as follows; condition 1 to condition 2 comparison; 41% hip flexion, 59% hip extension, 53% hip abduction, 47% hip adduction, 62% knee flexion, 38% knee extension, 59% knee abduction, 41% knee adduction, 47% ankle dorsiflexion, 53% ankle plantarflexion, condition 1 to condition 3 comparison; 35% hip flexion, 65% hip extension, 47% hip abduction, 53% hip adduction, 50% knee flexion, 50% knee extension, 41% knee abduction, 59% knee adduction, 59% ankle dorsiflexion, 41% ankle plantarflexion and condition 1 to condition 4 comparison; 31% hip flexion, 69% hip extension, 38% hip abduction, 62% hip adduction, 60% knee flexion, 40% knee extension, 44% knee abduction, 56% knee adduction, 69% ankle dorsiflexion, 31% ankle plantarflexion. Conclusion: The result of this pilot study demonstrated that manipulating task with different constraints caused significant changes in players’ motor coordination patterns which supported the hypothesis of our study. Our findings suggest to develop ACL injury screening tests in a sport-specific setting.

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Effect of Frequency on Human Unipedal Hopping

Perceptual and Motor Skills ◽

10.2466/pms.2002.95.3.733 ◽

2002 ◽

Vol 95 (3) ◽

pp. 733-740 ◽

Cited By ~ 11

Author(s):

Gary P. Austin ◽

David Tiberio ◽

Gladys E. Garrett

Keyword(s):

Lower Extremity ◽

Knee Flexion ◽

Lower Extremities ◽

Ankle Dorsiflexion ◽

Vertical Force ◽

Two Dimensional ◽

Vertical Stiffness ◽

Hip Flexion ◽

Force Displacement ◽

Healthy Males

All mature forms of locomotion involve periods of unilateral stance. Unipedal hopping may provide useful information about the neuromuscular and biomechanical capabilities of a single lower extremity in adults. This study investigated whether hopping influenced vertical stiffness and lower extremity angular kinematics during human unipedal hopping. Vertical force and two-dimensional kinematics were measured in 10 healthy males hopping at three frequencies: preferred, +20%, and −20%. At +20%, compared to preferred, vertical stiffness increased 55% as hip flexion, knee flexion, and ankle dorsiflexion decreased, while at −20% vertical stiffness decreased 39.4% as hip flexion, knee flexion, and ankle dorsiflexion increased. As in bipedal hopping, the force-displacement relationship was more springlike at the preferred rate and +20% than at −20%. Given the prevalence of unilateral stance during walking, running, and skipping, findings related to unipedal hopping may be useful in the rehabilitation or conditioning of lower extremities.

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Changes in Lower Extremity Biomechanics Due to a Short-Term Fatigue Protocol

Journal of Athletic Training ◽

10.4085/1062-6050-48.2.03 ◽

2013 ◽

Vol 48 (3) ◽

pp. 306-313 ◽

Cited By ~ 27

Author(s):

Nelson Cortes ◽

Eric Greska ◽

Roger Kollock ◽

Jatin Ambegaonkar ◽

James A. Onate

Keyword(s):

Anterior Cruciate Ligament ◽

Lower Extremity ◽

Knee Flexion ◽

Cruciate Ligament ◽

Ligament Injury ◽

Initial Contact ◽

Fatigue Protocol ◽

Lower Extremity Biomechanics ◽

Anterior Cruciate ◽

Hip Flexion

Context: Noncontact anterior cruciate ligament injury has been reported to occur during the later stages of a game when fatigue is most likely present. Few researchers have focused on progressive changes in lower extremity biomechanics that occur throughout fatiguing. Objective: To evaluate the effects of a sequential fatigue protocol on lower extremity biomechanics during a sidestep-cutting task (SS). Design: Controlled laboratory study. Setting: Laboratory. Patients or Other Participants: Eighteen uninjured female collegiate soccer players (age = 19.2 ± 0.9 years, height = 1.66 ± 0.5 m, mass = 61.6 ± 5.1 kg) volunteered. Intervention(s): The independent variable was fatigue level, with 3 levels (prefatigue, 50% fatigue, and 100% fatigue). Using 3-dimensional motion capture, we assessed lower extremity biomechanics during the SS. Participants alternated between a fatigue protocol that solicited different muscle groups and mimicked actual sport situations and unanticipated SS trials. The process was repeated until fatigue was attained. Main Outcome Measure(s): Dependent variables were hip- and knee-flexion and abduction angles and internal moments measured at initial contact and peak stance and defined as measures obtained between 0% and 50% of stance phase. Results: Knee-flexion angle decreased from prefatigue (−17° ± 5°) to 50% fatigue (−16° ± 6°) and to 100% fatigue (−14° ± 4°) (F2,34 = 5.112, P = .004). Knee flexion at peak stance increased from prefatigue (−52.9° ± 5.6°) to 50% fatigue (−56.1° ± 7.2°) but decreased from 50% to 100% fatigue (−50.5° ± 7.1°) (F2,34 = 8.282, P = 001). Knee-adduction moment at peak stance increased from prefatigue (0.49 ± 0.23 Nm/kgm) to 50% fatigue (0.55 ± 0.25 Nm/kgm) but decreased from 50% to 100% fatigue (0.37 ± 0.24) (F2,34 = 3.755, P = 03). Hip-flexion angle increased from prefatigue (45.4° ± 10.9°) to 50% fatigue (46.2° ± 11.2°) but decreased from 50% to 100% fatigue (40.9° ± 11.3°) (F2,34 = 6.542, P = .004). Hip flexion at peak stance increased from prefatigue (49.8° ± 9.9°) to 50% fatigue (52.9° ± 12.1°) but decreased from 50% to 100% fatigue (46.3° ± 12.9°) (F2,34 = 8.639, P = 001). Hip-abduction angle at initial contact decreased from prefatigue (−13.8° ± 6.6°) to 50% fatigue (−9.1° ± 6.5°) and to 100% fatigue (−7.8° ± 6.5°) (F2,34 = 11.228, P < .001). Hip-adduction moment decreased from prefatigue (0.14 ± 0.13 Nm/kgm) to 50% fatigue (0.08 ± 0.13 Nm/kgm) and to 100% fatigue (0.06 ± 0.05 Nm/kg) (F2,34 = 5.767, P = .007). Conclusions: The detrimental effects of fatigue on sagittal and frontal mechanics of the hip and knee were visible at 50% of the participants' maximal fatigue and became more marked at 100% fatigue. Anterior cruciate ligament injury-prevention programs should emphasize feedback on proper mechanics throughout an entire practice and not only at the beginning of practice.

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Comparison of Lower Extremity Kinematics and Hip Muscle Activation During Rehabilitation Tasks Between Sexes

Journal of Athletic Training ◽

10.4085/1062-6050-45.2.181 ◽

2010 ◽

Vol 45 (2) ◽

pp. 181-190 ◽

Cited By ~ 44

Author(s):

Maureen K. Dwyer ◽

Samantha N. Boudreau ◽

Carl G. Mattacola ◽

Timothy L. Uhl ◽

Christian Lattermann

Keyword(s):

Sex Differences ◽

Lower Extremity ◽

Knee Flexion ◽

Muscle Activation ◽

Gluteus Maximus ◽

Rectus Femoris ◽

Kinetic Chain ◽

Closed Kinetic Chain ◽

Hip Flexion ◽

Rehabilitation Exercises

Abstract Context: Closed kinetic chain exercises are an integral part of rehabilitation programs after lower extremity injury. Sex differences in lower extremity kinematics have been reported during landing and cutting; however, less is known about sex differences in movement patterns and activation of the hip musculature during common lower extremity rehabilitation exercises. Objective: To determine whether lower extremity kinematics and muscle activation levels differ between sexes during closed kinetic chain rehabilitation exercises. Design: Cross-sectional with 1 between-subjects factor (sex) and 1 within-subjects factor (exercise). Setting: Research laboratory. Patients or Other Participants: Participants included 21 women (age = 23 ± 5.8 years, height = 167.6 ± 5.1 cm, mass = 63.7 ± 5.9 kg) and 21 men (age = 23 ± 4.0 years, height = 181.4 ± 7.4 cm, mass = 85.6 ± 16.5 kg). Intervention(s): In 1 testing session, participants performed 3 trials each of single-leg squat, lunge, and step-up-and-over exercises. Main Outcome Measure(s): We recorded the peak joint angles (degrees) of knee flexion and valgus and hip flexion, extension, adduction, and external rotation for each exercise. We also recorded the electromyographic activity of the gluteus maximus, rectus femoris, adductor longus, and bilateral gluteus medius muscles for the concentric and eccentric phases of each exercise. Results: Peak knee flexion angles were smaller and peak hip extension angles were larger for women than for men across all tasks. Peak hip flexion angles during the single-leg squat were smaller for women than for men. Mean root-mean-square amplitudes for the gluteus maximus and rectus femoris muscles in both the concentric and eccentric phases of the 3 exercises were greater for women than for men. Conclusions: Sex differences were observed in sagittal-plane movement patterns during the rehabilitation exercises. Because of the sex differences observed in our study, future researchers need to compare the findings for injured participants by sex to garner a better representation of altered kinematic angles and muscle activation levels due to injury.

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Inﬂuence of prophylactic ankle tapes on lower-extremity kinematics during a stop-jump task in chronic ankle instability

10.31083/jomh.2021.068 ◽

2021 ◽

Keyword(s):

Lower Extremity ◽

Knee Flexion ◽

Ankle Instability ◽

Three Dimensional ◽

Lower Extremities ◽

Chronic Ankle Instability ◽

Ankle Dorsiflexion ◽

Ankle Inversion ◽

Motion System ◽

Hip Flexion

Background and objective: Numerous tape applications have been used in patients with chronic ankle instability (CAI). However, the effect of prophylactic ankle taping on lower-extremity kinematics is still not well understood. This study aimed to investigate the effects of traditional taping, ﬁbular repositioning taping, and kinesiology taping on the peak angles of the lower extremities in patients with CAI. Materials and Methods: A total of 14 men (age, 24.07 ± 4.46 years; height, 175.06 ± 5.10 cm; weight, 82.24 ± 10.38 kg (mean ± standard deviation)) with CAI identiﬁed using screening questionnaires (Cumberland Ankle Instability Tool, 17.64 ± 4.14; Foot and Ankle Ability Measure (FAAM) Activity of Daily Living, 86.69 ± 6.71; and FAAM Sports Subscale, 75.45 ± 6.70) participated. The peak angles of the hip, knee, and ankle joints during a stop-jump task, with and without tape application, were collected using a three-dimensional motion system. Results: The following peak angles were measured: hip ﬂexion, hip adduction (ADD), hip internal rotation (IR), knee ﬂexion, knee abduction (ABD), knee IR, ankle dorsiﬂexion, ankle inversion, and ankle ADD. No signiﬁcant differences were observed in the peak angle of each joint across conditions (hip ﬂexion, F(3,39) = 0.85, p = 0.47; hip ADD, F(1.729,22.478) = 1.90, p = 0.18; hip IR, F(1.632,21.220) = 0.67, p = 0.49; knee ﬂexion, F(3,39) = 1.24, p = 0.15; knee ABD, F(1.691,21.982) = 1.24, p = 0.30; knee IR, F(1.830,23.794) = 0.44, p = 0.63; ankle dorsiﬂexion, F(3,39) = 0.66, p = 0.58; ankle inversion, F(1.385,18.007) = 0.85, p = 0.40; ankle ADD, F(1.865,24.249) = 2.23, p = 0.13). Conclusion: The application of different taping techniques did not signiﬁcantly change the peak joint angles of the lower extremities during a stop-jump task. These results contradict those of previous studies, suggesting that ankle taping restricts joint range of motion.

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Lower Extremity Flexibility Profile in Basketball Players: Gender Differences and Injury Risk Identification

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph182211956 ◽

2021 ◽

Vol 18 (22) ◽

pp. 11956

Author(s):

Antonio Cejudo

Keyword(s):

Gender Differences ◽

Lower Extremity ◽

Injury Risk ◽

Sports Injuries ◽

Risk Identification ◽

Ankle Dorsiflexion ◽

Basketball Players ◽

Risk Of Injury ◽

Hip Abduction ◽

Hip Flexion

Analysis of the flexibility profile of basketball players (BPs) can reveal differences in range of motion (ROM) by gender and also identify those players who are at higher risk for sports injuries. A descriptive observational study was conducted to determine the lower extremity flexibility profile of sixty-four basketball players and gender differences to identify players at higher risk of injury due to limited and asymmetric ROM in one or more movements. Participants: Sixty-four (33 male and 31 female) competitive athletes from the national leagues of the Spanish basketball league system participated in the present study (power of sample size ≥0.99). The eight passive ROM tests of the hip, knee and ankle were assessed using the ROM-SPORT battery. Each player completed a questionnaire on age, basic anthropometric data, dominant extremities, and training and sport-related variables. The lower extremity flexibility profile was established at 15° and 10° hip extension (HE), 39° and 38° ankle dorsiflexion with knee extended (ADF-KE), 40° and 39° ankle dorsiflexion with knee flexed (ADF-KF), 43° and 43° hip abduction (HAB), 75° and 61° hip abduction with the hip flexed (HAB-HF), 78° and 83° hip flexion with the knee extended (HF-KE), 134° and 120° knee flexion (KF), and 145° and 144° hip flexion (HF) by male and female basketball players, respectively. Sex differences in HE, HAB-HF, and KF were observed in BPs (p ≤ 0.01; Hedges’ g ≥ 1.04). Players reported limited ROM in ADF-KF, HE, HAB-HF, HF-KE, and KF; and asymmetric ROM mainly in HE, ADF-KE, KF, ADF-KF, and HF-KE. In conclusion, this study provides gender-specific lower extremity flexibility profile scores in BPs that can help athletic trainers and athletic and conditioning trainers to identify those players who are at higher risk of injury due to abnormal ROM scores.

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Instruction and Jump-Landing Kinematics in College-Aged Female Athletes Over Time

Journal of Athletic Training ◽

10.4085/1062-6050-48.2.09 ◽

2013 ◽

Vol 48 (2) ◽

pp. 161-171 ◽

Cited By ~ 20

Author(s):

Jena Etnoyer ◽

Nelson Cortes ◽

Stacie I. Ringleb ◽

Bonnie L. Van Lunen ◽

James A. Onate

Keyword(s):

Lower Extremity ◽

Retention Test ◽

Knee Flexion ◽

Female Athletes ◽

Initial Contact ◽

Knee Valgus ◽

Drop Jump ◽

Jump Landing ◽

Peak Knee ◽

Hip Flexion

Context: Instruction can be used to alter the biomechanical movement patterns associated with anterior cruciate ligament (ACL) injuries. Objective: To determine the effects of instruction through combination (self and expert) feedback or self-feedback on lower extremity kinematics during the box–drop-jump task, running–stop-jump task, and sidestep-cutting maneuver over time in college-aged female athletes. Design: Randomized controlled clinical trial. Setting: Laboratory. Patients or Other Participants: Forty-three physically active women (age = 21.47 ± 1.55 years, height = 1.65 ± 0.08 m, mass = 63.78 ± 12.00 kg) with no history of ACL or lower extremity injuries or surgery in the 2 months before the study were assigned randomly to 3 groups: self-feedback (SE), combination feedback (CB), or control (CT). Intervention(s): Participants performed a box–drop-jump task for the pretest and then received feedback about their landing mechanics. After the intervention, they performed an immediate posttest of the box–drop-jump task and a running–stop-jump transfer test. Participants returned 1 month later for a retention test of each task and a sidestep-cutting maneuver. Kinematic data were collected with an 8-camera system sampled at 500 Hz. Main Outcome Measure(s): The independent variables were feedback group (3), test time (3), and task (3). The dependent variables were knee- and hip-flexion, knee-valgus, and hip- abduction kinematics at initial contact and at peak knee flexion. Results: For the box–drop-jump task, knee- and hip-flexion angles at initial contact were greater at the posttest than at the retention test (P < .001). At peak knee flexion, hip flexion was greater at the posttest than at the pretest (P = .003) and was greater at the retention test than at the pretest (P = .04); knee valgus was greater at the retention test than at the pretest (P = .03) and posttest (P = .02). Peak knee flexion was greater for the CB than the SE group (P = .03) during the box–drop-jump task at posttest. For the running–stop-jump task at the posttest, the CB group had greater peak knee flexion than the SE and CT (P ≤ .05). Conclusions: Our results suggest that feedback involving a combination of self-feedback and expert video feedback with oral instruction effectively improved lower extremity kinematics during jump-landing tasks.

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EFFECT OF STATIC ANATOMIC ALIGNMENT ON DYNAMIC LIMB VALGUS DURING SIDE-STEP CUTTING IN UNINJURED ADOLESCENT ATHLETES

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967119s00028 ◽

2019 ◽

Vol 7 (3_suppl) ◽

pp. 2325967119S0002

Author(s):

Nicole Mueske ◽

Daniel T. Feifer ◽

Curtis VandenBerg ◽

J. Lee Pace ◽

Mia J. Katzel ◽

...

Keyword(s):

Lower Extremity ◽

Internal Rotation ◽

Knee Flexion ◽

External Rotation ◽

Acl Injury ◽

Adolescent Athletes ◽

Knee Abduction ◽

Hip Flexion ◽

Hip Internal Rotation ◽

Hip Rotation

BACKGROUND Dynamic limb valgus, combining hip adduction and internal rotation with knee abduction posture and moments, has been implicated in ACL injury. However, the contribution of static lower extremity alignment to dynamic limb valgus is unknown. This study assessed the relationships among lower extremity static alignment and dynamic kinematics and kinetics during side-step cutting in uninjured adolescent athletes. METHODS This prospective study included 88 limbs from 44 uninjured athletes aged 8-15 years (mean 12.3, SD 2.3; 19 (44%) female) who were evaluated during an anticipated 45° side-step cut. 3D lower extremity kinematics and kinetics from a custom 6 degree of freedom model were assessed while standing and during the loading phase of the cut from initial contact to peak knee flexion; 2-3 trials per limb were averaged for analysis. Femoral anteversion was measured for each limb with the participant lying prone. Relationships among static and dynamic measures were investigated using correlation and multiple linear regression. RESULTS In terms of static alignment, more static hip internal rotation and more static knee external rotation (tibia external relative to femur) were associated with more internal hip rotation and external knee rotation dynamically during cutting (r=0.34, p=0.001) (Table 1). Static hip adduction was also related to more external hip rotation and less hip flexion dynamically (p=0.24, p=0.02). More static knee abduction, external hip rotation and hip adduction were associated with higher average knee abduction angles during cutting (r=0.25, p=0.02). However, only static external knee rotation was associated with higher dynamic knee abduction moments (r=0.48, p<0.0001) (Figure 1). During cutting, positive associations were observed between hip flexion, knee flexion, and hip internal rotation (r=0.24, p=0.03). Knee adduction angles were related to more hip flexion, internal hip rotation, and knee external rotation (r=0.25, p=0.02). Additionally, lower peak knee flexion was associated with higher peak ground reaction force and more external knee rotation (r=0.24, p=0.02). Both simple correlation and multiple regression analysis indicated that higher knee abduction moments were related dynamically to higher knee abduction angles, greater knee external rotation, higher hip abduction angles, and greater hip internal rotation (R2=0.72, p<0.001). After considering dynamic metrics, no static measure remained significantly related to knee abduction moments. CONCLUSION/SIGNIFICANCE Static knee rotation was the only anatomic alignment measure associated with knee abduction moments during side-step cutting in uninjured adolescent athletes. Knee abduction moments were influenced more by dynamic posture than static alignment. As knee abduction moments have been implicated in ACL injury, this study supports the notion of dynamic limb valgus, specifically increased knee abduction and hip internal rotation, relating to ACL injury. Motion analysis can be used to identify these risky biomechanical patterns, and neuromuscular training can be used to correct them. Since knee abduction moments are primarily determined by dynamic posture, neuromuscular training can be used to reduce these moments and ACL injury risk. [Figure: see text][Table: see text]

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