Asymmetrical Movement Patterns Research Articles

Biomechanical Comparison of Pediatric Female Ballet Dancers With and Without Pain

BACKGROUND: Across all genres of dance, studies have reported musculoskeletal injury in 20-84% of dancers with 95% reporting a history of musculoskeletal pain. Compared to other dance styles, ballet dancers specifically are most affected by musculoskeletal injuries. The purpose of this study is to compare movement patterns and muscle activity in pediatric female pre-professional dancers with and without self- reported pain, using the Patient-Reported Outcomes Measurement Information System pediatric numeric rating scale. We hypothesize dancers reporting pain will exhibit compensatory strategies, such as asymmetrical movement patterns and muscle activity, across a series of ballet movements. METHODS: A total of 55 female ballet dancers who train en pointe were seen for testing (age 14.4±1.9 years), with 34 dancers (62%) self-reported pain in the 7 days preceding testing. Biomechanical testing, performed in pointe shoes, included performance of static (5 classical ballet positions) and dynamic ballet movements (développé, arabesqué and grand jeté) while instrumented with surface electromyography (EMG) to capture muscle activity and inertial measurement (IMU) dual sensors on the trunk and lower extremities to capture movement patterns. The experimental setup allowed for measurement of trunk and lower extremity muscle activity, as well as trunk, hip, knee, and ankle joint angles in the sagittal, coronal, and transverse planes. Student’s t-test was used to compare the pain and no pain groups across all variables with statistical significance set to α=0.05. RESULTS: Movement patterns and EMG differences were seen between groups. During first and third positions, the right (non-barre sided) leg demonstrated less external knee rotation in the pain group (p≤0.05). In fifth position, the left (barre-sided) leg exhibited increased ankle flexion (p=0.048), reduced hip abduction (p=0.027), and reduced knee adduction (p=0.026) in the pain group. The pain group exhibited decreased trunk flexion/extension range-of-motion during the grand jeté (p=0.004), and increased trunk rotation range-of-motion when performing the arabesqué en pointe (p=0.034). Rectus femoris activation was reduced for the pain group on the left leg in fifth position (p<0.03). The up leg in the pain group during the développé (flat) showed increased hamstring activation (p=0.04). CONCLUSION: Ballet dancers with pain exhibited differences in movement patterns while performing certain ballet movements, notably during fifth position, grand jeté, and arabesqué (en pointe). Additionally, dancers with pain exhibited reduced rectus femoris activation in fifth position and increased hamstring activation on the working leg during the développé (flat). Future work should investigate how movement patterns and muscle activation in ballet dancers vary by location and severity of reported pain.

Bilateral Activity of Spine Extensors and Rotators during Asymmetric Lumbar Stabilization Exercises Executed in Prone, Quadruped, and Standing-Prone Positions

(1) Background: Most daily activities and sport gestures involve asymmetric movement patterns of the upper and lower extremities, transferring asymmetric mechanical loadings to the spine. Therefore, asymmetric lumbar stabilization exercises are frequently prescribed in athletic programs and preventive/rehabilitation interventions. This study analyzed the bilateral activity of the thoracic erector spinae (ES), lumbar multifidus (MF), external oblique (EO), and internal oblique (IO) during asymmetric lumbar stabilization exercises executed in prone, quadruped, and standing-prone positions, rising an upper and/or lower limb in all possible combinations. A limited subset of these data has been previously published in earlier studies. (2) Methods: Surface EMG signals were bilaterally recorded from the selected muscles using wireless EMG sensors. (3) Results: ES, MF, and oblique muscles’ activity was significantly higher in prone, standing-prone, and quadruped positions, respectively, and was maximized by specific limb rise combinations (up to 69%, 64%, 34%, and 24% maximum-voluntary-isometric-contraction for ES, MF, EO, and IO). The bilateral difference in muscle activation was significantly higher in the quadruped position and revealed different strategies used to stabilize the body in response to the different exercise conditions. (4) Conclusions: The study results can provide deeper insights into the stabilizing function of the lumbar and oblique muscles and aid in designing optimal progressions for lumbar stabilization exercises.

Effects of a Total Motion Release (TMR®) Protocol for the Single Leg Squat on Asymmetrical Movement Patterns.

Improving single leg squat (SLS) movement symmetry may benefit rehabilitation protocols. The Total Motion Release® (TMR®) protocol has been theorized to evaluate and improve patient-perceived movement asymmetries. The purpose of this study was to evaluate whether perceived asymmetries identified by a TMR® scoring protocol were related to biomechanical asymmetries and whether improving perceived asymmetries influenced movement mechanics. It was hypothesized that participants with perceived asymmetries would also present with biomechanical asymmetries. A secondary hypothesis was that participants would reduce their perceived asymmetries after performing the TMR® protocol and subsequently have greater biomechanical symmetry. Descriptive Cohort (Laboratory Study). Twenty participants (10 female, 10 male) with self-identified bilateral differences of 10 points or greater on the TMR® scoring scale were recruited for the study. The non-preferred side was defined as the side that scored higher. 3Dimensional motion capture was used to bilaterally assess baseline SLS depth as well as hip, knee, and ankle kinematics and kinetics. For the TMR® protocol, sets of 10 SLSs were performed on the preferred leg until their perceived asymmetries were resolved (i.e., both sides scored equally), or four sets had been completed. Kinematics and kinetics were collected immediately after the intervention and after a 10-minute rest period. Participants had biomechanical asymmetries at baseline for knee flexion, ankle flexion, and knee moments. Following the intervention, participants had reduced TMR® scores on the non-preferred leg, and this coincided with increased knee joint moments on that side. Although perceived asymmetries were resolved after the intervention, kinematic and kinetic asymmetries at the knee and ankle were still present. A TMR® intervention could benefit rehabilitation protocols by reducing factors of dysfunction and increasing the ability of patients to load the non-preferred knee. Further investigations are necessary to elucidate the importance of asymmetrical movement patterns. 3b.

Smile Reanimation with Masseteric-to-Facial Nerve Transfer plus Cross-Face Nerve Grafting in Patients with Segmental Midface Paresis: 3D Retrospective Quantitative Evaluation

Facial paresis involves functional and aesthetic problems with altered and asymmetric movement patterns. Surgical procedures and physical therapy can effectively reanimate the muscles. From our database, 10 patients (18–50 years) suffering from unilateral segmental midface paresis and rehabilitated by a masseteric-to-facial nerve transfer combined with a cross-face facial nerve graft, followed by physical therapy, were retrospectively analyzed. Standardized labial movements were measured using an optoelectronic motion capture system. Maximum teeth clenching, spontaneous smiles, and lip protrusion (kiss movement) were detected before and after surgery (21 ± 13 months). Preoperatively, during the maximum smile, the paretic side moved less than the healthy one (23.2 vs. 28.7 mm; activation ratio 69%, asymmetry index 18%). Postoperatively, no differences in total mobility were found. The activity ratio and the asymmetry index differed significantly (without/with teeth clenching: ratio 65% vs. 92%, p = 0.016; asymmetry index 21% vs. 5%, p = 0.016). Postoperatively, the mobility of the spontaneous smiles significantly reduced (healthy side, 25.1 vs. 17.2 mm, p = 0.043; paretic side 16.8 vs. 12.2 mm, p = 0.043), without modifications of the activity ratio and asymmetry index. Postoperatively, the paretic side kiss movement was significantly reduced (27 vs. 19.9 mm, p = 0.028). Overall, the treatment contributed to balancing the displacements between the two sides of the face with more symmetric movements.

Effects of Yoga Intervention on Functional Movement Patterns and Mindfulness in Collegiate Athletes: A Quasi-Experimental Study.

High-quality movement patterns and high levels of mindfulness are thought to be beneficial in preventing sports injuries. Yoga is recommended in the field of athlete rehabilitation. This study investigated the effects of yoga intervention on functional movement patterns and mindfulness in collegiate athletes. It is a quasi-experimental study with a pre/post-test control design. The participants were divided into a yoga group and a control group. A Functional Movement Screen and the Mindful Attention Awareness Scale were used to assess participants' basic movement patterns and mindfulness before and after 12 weeks of yoga intervention (two classes per week, 90 min per class). The results show that the yoga group's FMS scores improved more compared to the control group [F(1,78) = 29.08, p < 0.001, ŋp2 = 0.27], and that the scores for the deep squat (ŋp2 = 0.4), shoulder mobility (ŋp2 = 0.17), and trunk stability pushup (ŋp2 = 0.36) improved substantially. The dysfunctional score ratio for deep squats (χ2 = 18.57, p < 0.001), shoulder mobility (χ2 = 26.90, p < 0.001), trunk stability pushup (χ2 = 17.07, p < 0.001), and rotatory stability (χ2= 38.29, p <0.001) decreased significantly compared with the control group, but there was no significant improvement in asymmetric movement patterns (χ2 = 0.75, p = 0.39). The mindfulness scores in the yoga group significantly exceeded those of the control group [F(1,78) = 13.56, p < 0.001, ŋp2 = 0.15]. These results suggest that yoga intervention can improve functional movement patterns and mindfulness levels, but further evidence is needed to determine whether yoga could positively influence sports injuries.

ASSOCIATION OF LOWER LIMB STRENGTH ASYMMETRIES WITH STAIR AMBULATORY PAIN IN INDIVIDUALS WITH OR AT RISK FOR KNEE OA: DATA FROM THE OSTEOARTHRITIS INITIATIVE

Purpose: Walking and functional decline associated with knee osteoarthritis (OA) are significant, independent predictors of poor health state. Difficulty with stair ambulation can be an early response to pain and signal functional decline in individuals with or at risk for knee OA, resulting in asymmetrical movement patterns to reduce symptoms and compensate for associated muscle weakness. Lower limb strength asymmetry has been associated with increased odds of secondary OA development, with a 1% increase in quadriceps symmetry index (SI) resulting in a 4% lower odds of clinical OA development.

Identifying Gait Pathology after ACL Reconstruction Using Temporal Characteristics of Kinetics and Electromyography.

Asymmetrical gait mechanics after anterior cruciate ligament reconstruction (ACLR) are associated with the development of posttraumatic knee osteoarthritis. Current measures of gait mechanics have focused heavily on peak magnitudes of knee kinematics, kinetics, and joint contact forces but have seldom considered the rate of knee loading, cumulative knee load, or the timing of motor input surrounding peaks. The purpose of this study was to introduce and describe novel metrics of gait using temporal characteristics of kinetics and EMG to identify neuromuscular deficits of the quadriceps in patients after ACLR. Gait mechanics were assessed 6 months (n = 145) and 24 months (n = 116) after ACLR. External knee flexion rate of moment development (RMD) and knee flexion moment impulse (KFMI) leading up to the time of peak knee flexion moment (pKFM), peak RMD between initial contact to pKFM, and cumulative KFMI were calculated. Extensor latencies from the quadriceps, vastus medialis, vastus lateralis, and rectus femoris (time of pKFM - time of peak EMG activity) during the weight acceptance phase of gait were also calculated. Paired-sample t-tests (α = 0.05) were performed between limbs at both time points. Slower RMD, smaller KFMI, and longer extensor latencies in the involved compared with uninvolved limb were observed across all measures at 6 months (P < 0.005). At 24 months, RMDpeak was slower, and KFMI50ms, KFMI100ms, and KFMItotal were lower in the involved limb (P < 0.003), but no other asymmetries were found. Slower RMD, smaller KFMI, and prolonged extensor latencies may characterize neuromuscular deficits underlying aberrant gait mechanics early after ACLR. RMD, KFMI, and extensor latencies during gait should be considered in the future to quantify asymmetrical movement patterns observed after ACLR and as markers of recovery.

Effective Interventions for Improving Functional Movement Screen Scores Among "High-Risk" Athletes: A Systematic Review.

BackgroundThe Functional Movement ScreenTM (FMSTM) is a tool designed to screen a series of movements that aids in the identification of compensatory fundamental movement patterns, functional limitations, and asymmetrical movement patterns. A previous systematic review and meta-analysis has shown that athletes with an FMSTM score <13-14 are considered “high-risk” and are more likely to be injured. There are discrepancies regarding the efficacy of physical intervention programs in improving FMSTM scores.PurposeThe aim of this systematic review was to assess the role of physical intervention programs in increasing functional movement in “high-risk” athletes as measured by the FMSTM.Study DesignSystematic ReviewMethodsA computerized search was performed in 2019 according to PRISMA guidelines searching Embase, Science Direct, Ovid, and PubMed. The studies were assessed for quality and risk of bias using the Modified Downs and Black checklist. Participant demographics, intervention routines, and FMSTM scores were extracted from the included studies.ResultsSix studies met the inclusion criteria and demonstrated a fair methodological quality. Comparisons across all studies revealed significant improvement in FMSTM scores following implementation of a variety of physical intervention programs. These programs included those that utilized functional training, foot muscle strengthening, Pilates, core stability training, and resistance movements. Despite variations in the corrective exercises performed, the number of training sessions, and the length of the intervention program, all studies demonstrated an increase in the total FMSTM score following program implementation.ConclusionThe included intervention programs significantly improved total FMSTM scores in “high-risk” athletes. Despite variations in the corrective exercises (interventions) performed, the number of training sessions, and the length of the program, all studies demonstrated a significant increase in the total FMSTM score following program implementation.

Optimizing Exercise Selection for the Asymmetric Athlete After Anterior Cruciate Ligament Reconstruction

ABSTRACT Persistent deficits in quadriceps strength occur after anterior cruciate ligament (ACL) reconstruction and should be addressed to facilitate safe return to sport. Asymmetric movement patterns that shield the affected knee by shifting demands to the unaffected lower extremity, or other joints within the affected limb, may limit the ability of common strength training exercises to effectively mitigate quadriceps weakness. A multifaceted approach focusing on the early restoration of symmetrical loading during the squat, programming isolated knee extensions, and varying exercise selection to include split-stance positions, such as the split-squat and lunge, may result in the successful restoration of quadriceps strength after ACL reconstruction.

Gait Mechanics in Women of the ACL-SPORTS Randomized Control Trial: Interlimb Symmetry Improves Over Time Regardless of Treatment Group.

Women after anterior cruciate ligament (ACL) injury and ACL reconstruction (ACLR) are more likely than men to exhibit asymmetric movement patterns, which are associated with post-traumatic osteoarthritis. We developed the ACL specialized post-operative return-to-sports (ACL-SPORTS) randomized control trial to test the effect of strength, agility, plyometric, and secondary prevention (SAPP) training with and without perturbation training (SAPP + PERT) on gait mechanics in women after ACLR. We hypothesized that movement symmetry would improve over time across both groups but more so among the SAPP + PERT group. Thirty-nine female athletes 3-9 months after primary ACLR were randomized to SAPP or SAPP + PERT training. Biomechanical testing during overground walking occurred before (Pre-training) and after (Post-training) training and one and 2 years post-operatively. Hip and knee kinematic and kinetic variables were compared using repeated measures analysis of variance with Bonferroni corrections for post hoc comparisons (α = 0.05). There was a time by limb interaction effect (p = 0.028) for peak knee flexion angle (PKFA), the primary outcome which powered the study, characterized by smaller PKFA in the involved compared to uninvolved limbs across treatment groups at Pre-training, Post-training, and 1 year, but not 2 years. Similar findings occurred across sagittal plane knee excursions and kinetics and hip extension excursion at midstance. There were no meaningful interactions involving group. Neither SAPP nor SAPP + PERT training improved walking mechanics, which persisted 1 but not 2 years after ACLR. Statement of clinical significance: Asymmetrical movement patterns persisted long after participants achieved symmetrical strength and functional performance, suggesting more time is needed to recover fully after ACLR. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1743-1753, 2019.

A preliminary study investigating functional movement screen test scores in female collegiate age horse-riders

The functional movement screen (FMS) is an easily administered and non-invasive tool to identify areas of weakness and asymmetry during specific exercises. FMS is a common method of athlete screening in many sports and is used to ascertain injury risk, but has to be used within an equestrian population. The aim of this study was to establish FMS scores for female collegiate age (18-26 years) riders, to inform a normative data set of FMS scores in horse riders in the future. Thirteen female collegiate horse riders (mean ± standard deviation (sd); age 21.5±1.4 years, height 167.2±5.76 cm, mass 60.69±5.3 kg) and 13 female collegiate non-riders (mean ± sd; age 22.5±2.1 years, height 166.5±5.7 cm, mass 61.5±4.9 kg) were assessed based on their performance on a 7-point FMS (deep squat, hurdle step, in-line lunge, shoulder mobility, active straight leg raise, trunk stability and rotary stability). The mean composite FMS scores (± sd) for the rider group was 14.15±1.9 and for the non-riders was 13.15±1.77. There was no statistically significant difference in median FMS composite scores between the rider and non-rider groups (Mann-Whitney U test, z=-1.249, P =0.223). However, 46% of riders and 69% of non-riders scored ≤14, indicating that a non-rider is 1.5 times (odds ratio) more likely to be at increased risk of injury compared to riders. Collegiate female riders scored higher than the non-rider population, but lower than seen in other sports suggesting some riders may be at risk of injury. Riders’ FMS scores demonstrated asymmetric movement patterns potentially limiting left lateral movement. Asymmetry has a potential impact on equestrian performance, limiting riders’ ability to apply the correct cues to the horse. The findings of such screening could inform the development of axillary training programmes to correct asymmetry pattern and target injury prevention.

Stiff knee gait may increase risk of second total knee arthroplasty.

Osteoarthritis (OA) progression in the contralateral limb after unilateral total knee arthroplasty (TKA) may be related to altered and asymmetrical movement patterns that overload the contralateral joints. The purpose of this study was to determine if biomechanical factors after unilateral TKA were associated with future contralateral TKA. One hundred and fifty-eight individuals who underwent unilateral TKA completed three dimensional motion analysis 6-24 months after unilateral TKA (baseline). Subjects were re-contacted for follow-up (mean 5.89 years after baseline testing) to determine if they had undergone a contralateral TKA. Biomechanical variables from gait at baseline were compared between those who did and did not undergo contralateral TKA at follow-up using one-way ANOVAs. Odds ratios were calculated for variables found to be significant in the ANOVA models. Individuals who underwent contralateral TKA had less knee flexion excursion (10.5° vs. 12.1°; p = 0.032) and less knee extension excursion (8.2° vs. 9.6°; p = 0.035) at baseline on the operated side during walking. Individuals who underwent contralateral TKA also had less knee flexion excursion on the contralateral limb at baseline (11.9° vs. 14.0°; p = 0.017). For every additional degree of knee flexion excursion on the contralateral knee at baseline, there was a 9.1% reduction in risk of future contralateral TKA. Individuals who walked with stiffer gait patterns were more likely to undergo future contralateral TKA. Clinical Significance: Altered movement patterns after surgery may increase the risk for contralateral TKA. Knee excursion is an important metric to include in outcome studies and may serve as a target of rehabilitation after TKA. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:397-402, 2019.

Behavioural asymmetry in Devonian trilobites

The cephalon of the trilobite Phacopidae was usually separated from the thorax during moulting, and abandoned near the trunk. We statistically evaluated the distribution pattern of the cephala of Omegops cornelius, and found that near 70% of the total cephala were displaced on the right side, from the Upper Devonian deposits of the western Junggar in Northwest China. Omegops cornelius might have actively pushed the cephalon to the right of its body during moulting, indicating their preference to move counterclockwise. This preferred movement direction manifested the behavioural asymmetry in trilobites. A different type of asymmetry has been observed in Phacopidae Plagiolaria nandanensis from the Lower Devonian of Guangxi in South China, where about 67% of the cephala were found on the left side of the trilobite trunks. So the behavioural asymmetry may be diverse (or opposite) in different species of trilobites, and the reasons for the asymmetric moulting and movement patterns of the above two trilobites are likely related to their body structures, or their living environments. These new materials provide evidence for studying the origin and evolution of behavioural asymmetry.

Asymmetry of lumbopelvic movement patterns during active hip abduction is a risk factor for low back pain development during standing

An induced-pain paradigm has been used in back-healthy people to understand risk factors for developing low back pain (LBP) during prolonged standing. We examined asymmetry of lumbopelvic movement timing during a clinical test of active hip abduction in back-healthy people who developed LBP symptoms during standing (Pain Developers; PDs) compared to back-healthy people who did not develop LBP symptoms during standing (Non Pain Developers, NPDs). Participants completed the hip abduction test while movement was recorded with a motion capture system. Difference in time between start of hip and lumbopelvic movement was calculated (startdiff). PDs moved the lumbopelvic region earlier during left hip abduction than right hip abduction. There was no difference between sides in NPDs. In PDs, the amount of asymmetry was related to average symptom intensity during standing. Asymmetric lumbopelvic movement patterns may be a risk factor for LBP development during prolonged standing.

Lower Extremity Musculoskeletal Injury History, Strength, and Biomechanics in Female US Army Soldiers

Female Soldiers have a significantly higher rate of injury, specifically low back and lower extremity (LB/LE) injuries, compared to male Soldiers. Despite return to full activity following an injury, LE biomechanical asymmetries may persist, likely leading to an increased risk for recurrent injuries. PURPOSE: To assess musculoskeletal and biomechanical asymmetries that may relate to the development of injury in female Soldiers. METHODS: Female 101st Airborne Division (Air Assault) Soldiers’ (n=77; age=27.1±5.9) LE strength (% body weight) and LE biomechanics were collected with 3D motion analysis during a drop landing task. Paired samples t-tests compared bilateral strength and landing biomechanics in female Soldiers. SPSS v.23 was utilized for analysis (p<0.05). RESULTS: Among all female Soldiers, 15.6% (12/77) reported at least one LB/LE injury within the last year, with half of those with injuries reporting a knee injury. The majority of all injuries and specifically knee injuries occurred on the right side. Significant asymmetries were found in knee extension strength (R:186.8±39.0 %BW vs L:171.9 ± 39.5 %BW, p<0.001), knee flexion strength (R:90.9.8±22.3 %BW vs L:86.5±21.1 %BW, p=0.001), knee flexion at initial contact (IC) (R:19.9±6.9° vs L:21.2±6.7°, p=0.33), knee flexion excursion (R:69.5±11.8° vs L:67.5±12.0°, p=0.004) and peak vertical ground reaction force (PvGRF) (R:350.3±88.6 %BW vs L:327.2±84.8 %BW, p<0.001). CONCLUSION: Female Soldiers demonstrated asymmetrical landing strategies, including decreased right knee flexion at IC and increased right PvGRF, potentially placing an increased load on the right limb, which was also the most injured limb. This stiffened landing position and greater PvGRF were found despite greater knee strength and increased knee flexion excursion on the right. These results suggest that in female Soldiers, shock absorption strategies at the knee may be influenced by mechanisms other than maximal knee strength. Further research is needed to determine the interaction between sagittal and frontal plane mechanics during landing in female Soldiers. With the expanded role of women in the military, understanding the mechanisms associated with these asymmetrical movement patterns and increased risk of injury should be a priority in military medicine.

Back Pain and Musculoskeletal Disorders in Multiple Sclerosis

Introduction: Musculoskeletal disorders and back pain can occur as a result of irregular, asymmetric movement patterns and postures due to muscular weakness, spasticity or imbalance in Multiple Sclerosis (MS). The aim was to investigate musculoskeletal disorders and risk factors of low back pain in MS patients. Methods: In this study, patients followed in our large MS centre with confirmed MS with an EDSS score between 4 to 7 were selected. Data of MS history, pain, musculoskeletal disorders, muscle strength and spasticity in lower limbs were collected. Results: 190 patients were included. The mean age of the patients was 54.9 ± 9.2 years and 32.1% participants were man. The mean disease duration was 19.3 ± 9.9 years, and the median EDSS score was 6. 48.9% of patients had a secondary progressive form and 27.4% had a relapse remitting form. The most common musculoskeletal disorders were: knee osteoarthritis (7.9%), claw toe (6.8%) and genu recurvatum (6.3%). The prevalence of low back pain was 41.6% and was higher in patients with a progressive form (secondary: OR=2.96 (p=0,0079) and primitive OR=2.63; p=0.0398)) or a visual dysfunction at EDSS score (OR=1.41 (p=0.0124)) and decreased in male patients (OR= 0.31 (p=0.0014)). Conclusions: A progressive form of MS and visual dysfunction increased the risk of low back pain in these patients.

Evaluation Of Three-Dimensional Motion During Side-step Cutting After Anterior Cruciate Ligament Reconstruction in Pediatric Athletes

Objectives:This study assessed three-dimensional kinematic and kinetic data during side-step cutting in young athletes following anterior cruciate ligament (ACL) reconstruction.Methods:The study included 28 pediatric athletes (mean age 15.6 ± 2.2 years) who underwent ACL reconstruction due to a non-contact injury. Lower extremity and trunk three-dimensional kinematic and kinetic data was collected during a side-step cut. Testing occurred within 12 months (mean time since surgery 5.3 ± 2.1 months) post-surgery. Outcomes were evaluated at initial foot contact and between initial foot contact and maximum knee flexion of the cutting limb. Differences between the operative limb and non-operative (contralateral) limb were investigated using paired t-tests.Results:The operative limb had higher peak adduction (-0.14° ± 7.3 vs. -6.1° ± 5.0, p=0.001) and higher peak pelvic obliquity (14.0° ±6.2 vs. 10.5° ±5.7, p=0.01) compared to the non-operative limb. While there was no significant difference in peak ground reaction force (23.2 N/kg ± 4.7 vs. 24.5 N/kg ± 4.5, p=0.15), the operative limb had lower peak knee flexion (53.3° ± 13.5 vs. 59.6° ±10.0, p=0.004), ankle dorsiflexion (14.5° ± 7.5 vs. 18.6° ± 6.5, p=0.007), and external knee flexor moment (1.4 Nm/kg ± 0.61 vs. 1.9 Nm/kg ± 0.62, p=0.002) leading to the operative limb having less power absorption at the knee (0.38 Ws/kg ± 0.31 vs. 0.58 Ws/kg ± 0.28, p=0.005). At initial contact the operative limb was more adducted (-5.0° ± 7.6 vs. -8.6° ± 3.9; p=0.02) and flexed (56.3° ± 11.4 vs. 52.5° ± 12.7; 0.06) at the hip and more flexed at the knee (21.5° ± 17.1 vs. 17.2° ± 13.6; p=0.06). The operative limb also had more pelvic elevation (8.1° ± 7.0 vs. 5.5° ± 3.8; p=0.04) and had more trunk rotation (rotation relative to the lab; -11.4° ±7.2 vs. -5.3° ±8.6; p=0.004). Eight of the 28 operative limbs had an asymmetry greater than 10% of the non-operative limb on one of the kinematic or kinetic variables; though all eight limb asymmetries occurred on different movement variables.Conclusion:Following ACL reconstruction pediatric athletes exhibit asymmetry several months post-surgery. The operative limb displayed deficits and asymmetry in hip control and shock absorption strategies after initial contact until maximum knee flexion which could increase the risk of future re-injury based on prior biomechanical studies. The contralateral limb also demonstrated deficits and asymmetries at initial contact. These asymmetrical movement patterns and deficits potentially put the non-operative limbs at an increased risk for injury and potentially lend insight into why patients who tear one ACL are at increased risk of contralateral ACL injury. If asymmetry is indicative of future injury risk, this should be considered during treatment, rehabilitation and return to sport decision-making.

Heading in the Right Direction: Understanding Head Turn Preference in the Preterm Infant

Abstract Date Presented 4/17/2015 Head turn preference in the preterm infant is not associated with medical factors in the neonatal intensive care unit (NICU); however, it is associated with early neurobehavior and asymmetric movement patterns, and it is also a marker for adverse developmental outcome at age 2 yr.

Spatial asymmetries in connectivity influence colonization-extinction dynamics.

Movement has broad implications for many areas of biology, including evolution, community and population ecology. Movement is crucial in metapopulation ecology because it facilitates colonization and reduces the likelihood of local extinction via rescue effects. Most metapopulation modeling approaches describe connectivity using pair-wise Euclidean distances resulting in the simplifying assumption of a symmetric connectivity pattern. Yet, assuming symmetric connectivity when populations show net asymmetric movement patterns may result in biased estimates of colonization and extinction, and may alter interpretations of the dynamics and conclusions regarding the viability of metapopulations. Here, we use a 10-year time series on a wind-dispersed orchid Lepanthes rupestris that anchors its roots in patches of moss growing on trees or boulders along streams, to test for the role of connectivity asymmetries in explaining the colonization-extinction dynamics of this orchid in a network of 975 patches. We expected that wind direction could highly alter dispersal direction in this orchid. To account for this potential asymmetry, we modified the connectivity measure traditionally used in metapopulation models to allow for asymmetric effective distances between patches and subsequently estimated colonization and extinction probabilities using a dynamic occupancy modeling approach. Asymmetric movement was prevalent in the L. rupestris metapopulation and incorporating potential dispersal asymmetries resulted in higher colonization estimates in larger patches and more accurate models. Accounting for dispersal asymmetries may reveal connectivity effects where they were previously assumed to be negligible and may provide more reliable conclusions regarding the role of connectivity in patch dynamics.

Evaluation of a Side-Step Cut After Anterior Cruciate Ligament Reconstruction

PURPOSE: This study assessed kinematics and kinetics during side-step cutting in young athletes following anterior cruciate ligament (ACL) reconstruction. METHODS: The study included 28 pediatric athletes (mean age 15.6 ± 2.2 years) who underwent ACL reconstruction due to a non-contact injury. Lower extremity and trunk three-dimensional kinematic and kinetic data was collected during a side-step cut. Testing occurred within 12 months (mean time since surgery 5.3 ± 2.1 months) post-surgery. Outcomes were evaluated at initial foot contact and between initial foot contact and maximum knee flexion of the cutting limb. Differences between the operative limb and non-operative (contralateral) limb were investigated using paired t-tests. RESULTS: The operative limb had higher peak adduction (p=0.001) and higher peak pelvic obliquity (p=0.02) compared to the non-operative limb. While there was no significant difference in peak ground reaction force (p=0.15), the operative limb had lower peak knee flexion (p=0.004), ankle dorsiflexion (p=0.07), and external knee flexor moment (p=0.002) leading to the operative limb having less power absorption at the knee (p=0.005). At initial contact the operative limb was more adducted (p=0.02) and flexed (0.06) at the hip and more flexed at the knee (p=0.06). The operative limb also had more pelvic elevation (p=0.04) and had more trunk rotation (p=0.004). Eight of the 28 operative limbs had an asymmetry greater than 10% of the non-operative limb on one of the kinematic or kinetic variables; though all eight limb asymmetries occurred on different movement variables. CONCLUSIONS: Following ACL reconstruction pediatric athletes exhibit asymmetry several months post-surgery. The operative limb displayed deficits and asymmetry in hip control and shock absorption strategies after initial contact until maximum knee flexion which could increase the risk of future re-injury based on prior biomechanical studies. The contralateral limb also demonstrated deficits and asymmetries at initial contact. These asymmetrical movement patterns and deficits potentially put the non-operative limbs at an increased risk for injury and potentially lend insight into why patients who tear one ACL are at increased risk of contralateral ACL injury. If asymmetry is indicative of future injury risk, this should be considered during treatment, rehabilitation and return to sport decision-making.