Adam R. Marmon

Validity Of The Nintendo Wii Balance Board To Assess Weight Bearing Asymmetry During Sit-To-Stand And Return-To-Sit Task

Weight bearing asymmetry is common in patients with unilateral lower limb musculoskeletal pathologies. The Nintendo Wii Balance Board (WBB) has been suggested as a low-cost and widely-available tool to measure weight bearing asymmetry in a clinical environment; however no study has evaluated the validity of this tool during dynamic tasks. Therefore, the purpose of this study was to determine the concurrent validity of force measurements acquired from the WBB as compared to laboratory force plates. Thirty-five individuals before, or within 1 year of total joint arthroplasty performed a sit-to-stand and return-to-sit task in two conditions. First, subjects performed the task with both feet placed on a single WBB. Second, the task was repeated with each foot placed on an individual laboratory force plate. Peak vertical ground reaction force (VGRF) under each foot and the inter-limb symmetry ratio were calculated. Validity was examined using Intraclass Correlation Coefficients (ICC), regression analysis, 95% limits of agreement and Bland-Altman plots. Force plates and the WBB exhibited excellent agreement for all outcome measurements (ICC=0.83-0.99). Bland-Altman plots showed no obvious relationship between the difference and the mean for the peak VGRF, but there was a consistent trend in which VGRF on the unaffected side was lower and VGRF on the affected side was higher when using the WBB. However, these consistent biases can be adjusted for by utilizing regression equations that estimate the force plate values based on the WBB force. The WBB may serve as a valid, suitable, and low-cost alternative to expensive, laboratory force plates for measuring weight bearing asymmetry in clinical settings.

Sit-To-Stand Biomechanics Before and After Total Hip Arthroplasty.

The purpose of this study was to evaluate changes in movement patterns during a sit-to-stand (STS) task before and after total hip arthroplasty (THA), and to compare biomechanical outcomes after THA to a control group. Forty-five subjects who underwent THA and twenty-three healthy control subjects participated in three-dimensional motion analysis. Pre-operatively, subjects exhibited inter-limb movement asymmetries with lower vertical ground reaction force (VGRF) and smaller moments on the operated limb. Although there were significant improvements in movement symmetry 3 months after THA, patients continued to demonstrate lower VGRF and smaller moments on the operated limb compared to non-operated and to control limbs. Future studies should identify the contributions of physical impairments and the influence of surgical approach on STS biomechanics.

Perception and Presentation of Function in Patients with Unilateral Versus Bilateral Knee Osteoarthritis

Lower extremity functional performance and perception of functional abilities influence clinical management in people diagnosed with unilateral or bilateral knee osteoarthritis (OA). The purpose of this study was to determine if there were differences in perception of function and performance during functional tasks between individuals with unilateral and bilateral knee OA.

Activity Demands During Multi-Directional Team Sports: A Systematic Review

BackgroundLate-stage rehabilitation programs often incorporate ‘sport-specific’ demands, but may not optimally simulate the in-game volume or intensity of such activities as sprinting, cutting, jumping, and lateral movement.ObjectiveThe aim of this review was to characterize, quantify, and compare straight-line running and multi-directional demands during sport competition.Data SourcesA systematic review of PubMed, CINAHL, SPORTDiscus, and Cochrane Central Register of Controlled Trials databases was conducted.Study Eligibility CriteriaStudies that reported time-motion analysis data on straight-line running, accelerations/decelerations, activity changes, jumping, cutting, or lateral movement over the course of an entire competition in a multi-directional sport (soccer, basketball, lacrosse, handball, field hockey, futsal, volleyball) were included.Study Appraisal and Synthesis MethodsData was organized based on sport, age level, and sex and descriptive statistics of the frequency, intensity, time, and volume of the characteristics of running and multi-directional demands were extracted from each study.ResultsEighty-one studies were included in the review (nxa0=xa047 soccer, nxa0=xa011 basketball, nxa0=xa09 handball, nxa0=xa07 field hockey, nxa0=xa03 futsal, nxa0=xa04 volleyball). Variability of sport demand data was found across sports, sexes, and age levels. Specifically, soccer and field hockey demanded the most volume of running, while basketball required the highest ratio of high-intensity running to sprinting. Athletes change activity between 500 and 3000 times over the course of a competition, or once every 2–4xa0s. Studies of soccer reported the most frequent cutting (up to 800 per game), while studies of basketball reported the highest frequency of lateral movement (up to 450 per game). Basketball (42–56 per game), handball (up to 90 per game), and volleyball (up to 35 per game) were found to require the most jumping.LimitationsThese data may provide an incomplete view of an athlete’s straight-line running load, considering that only competition and not practice data was provided.ConclusionsConsiderable variability exists in the demands of straight-line running and multi-directional demands across sports, competition levels, and sexes, indicating the need for sports medicine clinicians to design future rehabilitation programs with improved specificity (including the type of activity and dosage) to these demands.

Lower leg compensatory strategies during performance of a step up and over task in patient six-months after total knee arthroplasty

The purpose of this study was to assess the ankle, knee, and hip joint contributions to the total support moment (TSM) and the activation patterns of muscles in the lower leg in patients after total knee arthroplasty (TKA) and healthy older adults during the step up and over task. Moreover, the relationship between quadriceps strength and knee contribution to TSM was measured. Twenty patients six-months after TKA and twenty healthy controls were recruited for this study. Motion and surface electromyographic (EMG) analyses were performed during a step up and over task. Biomechanics and EMG variables were compared between groups using ANCOVA models with movement speed as covariate. Patients after TKA had reduced contribution to the TSM from the knee joint, and greater contribution from the hip and ankle joints, possibly to compensate for the reduced contribution at the knee. No consistent differences of EMG activation or co-contraction were found between groups. Patients with stronger quadriceps had significantly higher knee contribution to TSM during the lowering phase of the task. The results of this study suggest that patients after TKA may use compensatory strategies at the hip and ankle joints to safely perform the step up and over task. Patients may rely on the force generating ability of the quadriceps during the lowering phase as they are not able to compensate with other joints of the lower extremity during this phase of the task.

Changes in biomechanical knee injury risk factors across two collegiate soccer seasons using the 11+ prevention program

The 11+ injury prevention program effectively reduces injuries in high school‐aged female soccer player, but the mechanism of the 11+ is unknown, particularly whether it impacts biomechanical risk factors associated with knee injuries. The purpose of this study was to report the changes in hip and knee biomechanics with use of the 11+ over two soccer seasons. Two collegiate womens soccer teams performed the 11+ for two soccer seasons. A control team was followed for one season. Athletes performed motion analysis of a drop vertical jump during preseason and postseason. Both groups had meaningful increases in peak knee abduction angle over the first season, and there were no meaningful changes in peak knee abduction moment over either season. The control group had bilateral decreases in knee flexion angle. The program did not seem to systematically impact biomechanical risk factors associated with knee injuries, with increases in peak knee abduction angle and no bilateral changes in frontal or transverse hip motion. The 11+ may have mitigated clinically meaningful decreases in knee flexion; however, as ACL injuries do not occur purely in the sagittal plane, it is unclear the impact of these changes. The results of this study indicate that the 11+ may require some modifications to impact landing biomechanics and potentially risky movement patterns, particularly when used in collegiate women over multiple seasons.

High muscle co-contraction does not result in high joint forces during gait in anterior cruciate ligament deficient knees: MUSCLE CO-CONTRACTION AND JOINT FORCES

The mechanism of knee osteoarthritis development after anterior cruciate ligament injuries is poorly understood. The objective of this study was to evaluate knee gait variables, muscle co‐contraction indices and knee joint loading in young subjects with anterior cruciate ligament deficiency (ACLD, nu2009=u200936), versus control subjects (nu2009=u200912). A validated, electromyography‐informed model was used to estimate joint loading. For the involved limb of ACLD subjects versus control, muscle co‐contraction indices were higher for the medial (pu2009=u20090.018, effect sizeu2009=u20090.93) and lateral (pu2009=u20090.028, effect sizeu2009=u20090.83) agonist–antagonist muscle pairs. Despite higher muscle co‐contraction, medial compartment contact force was lower for the involved limb, compared to both the uninvolved limb (mean differenceu2009=u20090.39 body weight, pu2009=u20090.009, effect sizeu2009=u20090.70) as well as the control limb (mean differenceu2009=u20090.57 body weight, pu2009=u20090.007, effect sizeu2009=u20091.14). Similar observations were made for total contact force. For involved versus uninvolved limb, the ACLD group demonstrated lower vertical ground reaction force (mean differenceu2009=u20090.08 body weight, pu2009=u20090.010, effect sizeu2009=u20090.70) and knee flexion moment (mean differenceu2009=u20091.32% body weight * height, pu2009=u20090.003, effect sizeu2009=u20090.76), during weight acceptance. These results indicate that high muscle co‐contraction does not always result in high knee joint loading, which is thought to be associated with knee osteoarthritis. Long‐term follow‐up is required to evaluate how gait alterations progress in non‐osteoarthritic versus osteoarthritic subjects.

Corticospinal and intracortical excitability differ between athletes early after ACLR and matched controls: EXCITABILITY DIFFERS EARLY AFTER ACLR

Neuromuscular impairments, such as quadriceps weakness and activation deficits, persist after anterior cruciate ligament reconstruction (ACLR). Recent research demonstrating changes in the function of the primary motor cortex after ACLR posits that quadriceps impairments may be influenced by reduced corticospinal excitability. The purpose of this study was to investigate whether the integrity of the neuromotor axis of the vastus medialis is altered in subjects 2 weeks post‐ACLR compared to uninjured control subjects. Eighteen athletes 2 weeks post‐ACLR and 18 age and sex matched uninjured control subjects participated in this cross‐sectional study. We quantified corticospinal (resting motor threshold, RMT; motor evoked potential amplitudes at 120% RMT, MEP120) and intracortical (inhibition and facilitation) excitability using single and paired pulse transcranial magnetic stimulation (TMS), respectively. We assessed spinal‐reflex excitability (H‐reflex amplitude normalized to maximal M‐wave, H/M ratio) using peripheral stimulation. Subjects post‐ACLR had higher RMTs (pu2009=u20090.001), greater MEP120 amplitudes (pu2009=u20090.001), and more asymmetric facilitation (pu2009=u20090.041) than the uninjured control subjects. No significant group differences were found for intracortical inhibition (pu2009=u20090.289) and H/M ratio (pu2009=u20090.332). Our findings indicate that both intracortical and corticospinal excitability of vastus medialis are bilaterally altered in subjects 2 weeks after ACLR. Given persistent neuromuscular deficits seen after ACLR, rehabilitation strategies targeting intracortical and corticospinal deficits may potentially improve clinical outcomes.

Physical Function After Total Knee Replacement: An Observational Study Describing Outcomes in a Small Group of Women From China and the United States

OBJECTIVEnTo describe physical function before and six months after Total Knee Replacement (TKR) in a small sample of women from China and the United States.nnnDESIGNnObservational.nnnSETTINGnCommunity environment.nnnOUTCOMESnBoth groups adhered to the Osteoarthritis Research Society International (OARSI) protocols for the 6-minute walk and 30-second chair stand. We compared physical function prior to TKR and 6 months after using linear regression adjusted for covariates.nnnPARTICIPANTSnWomen (N=60) after TKR.nnnINTERVENTIONSnNot applicable.nnnRESULTSnAge and body mass index in the China group (n=30; 66y and 27.0kg/m2) were similar to those in the U.S. group (n=30; 65y and 29.6kg/m2). Before surgery, the China group walked 263 (95% confidence interval [CI], -309 to -219) less meters and had 10.2 (95% CI, -11.8 to -8.5) fewer chair stands than the U.S. group. At 6 months when compared with the U.S. group, the China group walked 38 more meters, but this difference did not reach statistical significance (95% CI, -1.6 to 77.4), and had 3.1 (95% CI, -4.4 to -1.7) fewer chair stands. The China group had greater improvement in the 6-minute walk test than did the U.S. group (P<.001).nnnCONCLUSIONSnDespite having worse physical function before TKR, the China group had greater gains in walking endurance and similar gains in repeated chair stands than did the U.S. group after surgery.

BIOMECHANICAL CHANGES WITH FIFA11+ UTILIZATION OVER MULTIPLE SOCCER SEASONS

Background The FIFA11+ is a dynamic warm-up injury prevention program. Previous studies have examined its efficacy in reducing injuries, however no information is available on whether it changes targeted movement patterns. Objective The purpose of this study was to examine the changes in peak knee abduction moment (PKAM) over two soccer seasons using the FIFA11+. We hypothesized that athletes will have decreased PKAM over the first season, no changes in the off-season, and further decreases over the second season. Design Prospective non-randomized intervention study (control team data currently being collected). Setting Elite collegiate womens soccer. Patients (or Participants) First season N=83, off-season N=68, second season N=59. Interventions The FIFA11+ program was initiated during the preseason and completed throughout two consecutive soccer seasons as a warm-up prior to training sessions and games at least 3x/week. Researchers did not influence the training during the off-season. Main Outcome Measurements PKAM measured during motion analysis of a drop jump at pre- and postseason of two consecutive seasons. Repeated measures ANCOVAs were used to analyse the change over each season and the off-season, with baseline PKAM included in each model as a covariate. Results There was a significant main effect of time over the first season (preseason 0.24±0.01, postseason 0.23±0.01, p=0.02). PKAM was a significant covariate (p<0.01). There no main effect of time over the off-season (p=0.40), however, PKAM was a significant covariate (p<0.01). There was also no main effect of time over the second season (p=0.29), with PKAM again a significant covariate (p<0.01). Conclusions The FIFA11+ is effective in preventing injuries, however its mechanism is unknown. The preliminary results of this study indicate this injury reduction may not be occurring as a result of a decrease in PKAM in all athletes.