3D Motion Capture May Detect Spatiotemporal Changes in Pre-Reaching Upper Extremity Movements with and without a Real-Time Constraint Condition in Infants with Perinatal Stroke and Cerebral Palsy: A Longitudinal Case Series.

Perinatal stroke (PS), occurring between 20 weeks of gestation and 28 days of life, is a leading cause of hemiplegic cerebral palsy (HCP). Hallmarks of HCP are motor and sensory impairments on one side of the body-especially the arm and hand contralateral to the stroke (involved side). HCP is diagnosed months or years after the original brain injury. One effective early intervention for this population is constraint-induced movement therapy (CIMT), where the uninvolved arm is constrained by a mitt or cast, and therapeutic activities are performed with the involved arm. In this preliminary investigation, we used 3D motion capture to measure the spatiotemporal characteristics of pre-reaching upper extremity movements and any changes that occurred when constraint was applied in a real-time laboratory simulation. Participants were N = 14 full-term infants: N = six infants with typical development; and N = eight infants with PS (N = three infants with PS were later diagnosed with cerebral palsy (CP)) followed longitudinally from 2 to 6 months of age. We aimed to evaluate the feasibility of using 3D motion capture to identify the differences in the spatiotemporal characteristics of the pre-reaching upper extremity movements between the diagnosis group, involved versus uninvolved side, and with versus and without constraint applied in real time. This would be an excellent application of wearable sensors, allowing some of these measurements to be taken in a clinical or home setting.

Effects of Optimization Technique on Simulated Muscle Activations and Forces.

Two optimization techniques, static optimization (SO) and computed muscle control (CMC), are often used in OpenSim to estimate the muscle activations and forces responsible for movement. Although differences between SO and CMC muscle function have been reported, the accuracy of each technique and the combined effect of optimization and model choice on simulated muscle function is unclear. The purpose of this study was to quantitatively compare the SO and CMC estimates of muscle activations and forces during gait with the experimental data in the Gait2392 and Full Body Running models. In OpenSim (version 3.1), muscle function during gait was estimated using SO and CMC in 6 subjects in each model and validated against experimental muscle activations and joint torques. Experimental and simulated activation agreement was sensitive to optimization technique for the soleus and tibialis anterior. Knee extension torque error was greater with CMC than SO. Muscle forces, activations, and co-contraction indices tended to be higher with CMC and more sensitive to model choice. CMC's inclusion of passive muscle forces, muscle activation-contraction dynamics, and a proportional-derivative controller to track kinematics contributes to these differences. Model and optimization technique choices should be validated using experimental activations collected simultaneously with the data used to generate the simulation.

Gait, balance, and patient-reported outcomes during taxane-based chemotherapy in early-stage breast cancer patients.

BACKGROUND: Chemotherapy-induced peripheral neuropathy (CIPN) is a dose-limiting toxicity of several commonly used chemotherapy drugs including taxanes, vinca alkaloids, and platinum compounds. Development of CIPN is highly variable, both in self-reported symptoms and functional consequences, and can be severe enough to alter dose intensity. PURPOSE: To describe the natural histories of both patient-reported symptoms of CIPN and functional impairments in breast cancer patients undergoing taxane-based chemotherapy. METHODS: Thirty-three breast cancer patients (32 female/1 male; 47.8 ± 11.2 years; n = 17 stage II/n = 16 stage III) were enrolled. Patients completed self-reports of symptoms and function (e.g., EORTC QLQ-CIPN20) and objective measures of physical function (i.e., balance and gait testing) in an outpatient oncology clinic at five timepoints: (1) baseline-prior to starting chemotherapy, (2-4) before starting subsequent chemotherapy cycles, and (5) 1-3 months after receiving their last taxane infusion. RESULTS: Significant negative changes in both patient-reported outcomes and objective functional measures were observed. Decreased balance was observed after the first chemotherapy cycle (28% increase in medial-lateral excursion of the center of pressure, p = 0.016) and progressed with cumulative exposure (43% increase, p < 0.001). Patients also demonstrated slower walking speeds (5% decrease, p = 0.003) as they progressed through treatment. These functional deficits were mirrored with increased patient-reported symptom severity for all EORTC QLQ-CIPN20 subscales (all p < 0.05). CONCLUSION: This study longitudinally assessed patient-reported outcomes concurrently with balance and gait testing in patients undergoing taxane therapy. Taxane treatment was associated with the development of clinically relevant problems in both CIPN symptoms and patient function.

Do Neuromuscular Dentistry-Designed Mouthguards Enhance Dynamic Movement Ability in Competitive Athletes?

The purpose of this study was to examine the effect of a neuromuscular dentistry-designed mouthguard (NMDD) on dynamic movement ability. Forty-two competitive athletes (8 women, 21.9 ± 2.9 years, 66.8 ± 18.8 kg, 1.68 ± 0.11 m; 34 men, 22.8 ± 4.8 years, 77.4 ± 12.7 kg, 1.78 ± 0.08 m) with greater than 2 years' experience in their designated sport were enrolled in the study. Participants completed the Functional Movement Screen (FMS), modified Star Excursion Balance Test (mSEBT), and a single-leg landing (SLL) task. Each subject was tested with 3 separate mouthguard conditions in random order: (a) no mouthguard (NO), (b) over-the-counter boil-and-bite mouthguard (BB; Shockdoctor Gravity, (c) and an NMDD (Pure Power Elite). Data were analyzed using a repeated-measures analysis of variance for each variable. There were no differences between mouthguard conditions in each of the 7 individual components or composite FMS score (p > 0.05). No differences were seen in the anterior, posteromedial, or posterolateral movements of the mSEBT; overall composite score; or time-to-contact measurements (p > 0.05). The BB condition (2.16 Nm·kg) exhibited higher peak knee valgus moments (pKVM) on the right leg only when compared with the NMDD condition (1.95 Nm·kg; p = 0.003) but not the NO condition (2.09 Nm·kg; p = 0.7262) during the SLL task. No differences in pKVM were seen on the left leg (p = 0.324). In conclusion, an NMDD was not effective at enhancing or diminishing measures of dynamic movement ability compared with BB or NO conditions.

Physical Exam Risk Factors for Lower Extremity Injury in High School Athletes: A Systematic Review.

OBJECTIVE: A stated goal of the preparticipation physical evaluation (PPE) is to reduce musculoskeletal injury, yet the musculoskeletal portion of the PPE is reportedly of questionable use in assessing lower extremity injury risk in high school-aged athletes. The objectives of this study are: (1) identify clinical assessment tools demonstrated to effectively determine lower extremity injury risk in a prospective setting, and (2) critically assess the methodological quality of prospective lower extremity risk assessment studies that use these tools. DATA SOURCES: A systematic search was performed in PubMed, CINAHL, UptoDate, Google Scholar, Cochrane Reviews, and SportDiscus. Inclusion criteria were prospective injury risk assessment studies involving athletes primarily ages 13 to 19 that used screening methods that did not require highly specialized equipment. Methodological quality was evaluated with a modified physiotherapy evidence database (PEDro) scale. MAIN RESULTS: Nine studies were included. The mean modified PEDro score was 6.0/10 (SD, 1.5). Multidirectional balance (odds ratio [OR], 3.0; CI, 1.5-6.1; P < 0.05) and physical maturation status (P < 0.05) were predictive of overall injury risk, knee hyperextension was predictive of anterior cruciate ligament injury (OR, 5.0; CI, 1.2-18.4; P < 0.05), hip external:internal rotator strength ratio of patellofemoral pain syndrome (P = 0.02), and foot posture index of ankle sprain (r = -0.339, P = 0.008). CONCLUSIONS: Minimal prospective evidence supports or refutes the use of the functional musculoskeletal exam portion of the current PPE to assess lower extremity injury risk in high school athletes. Limited evidence does support inclusion of multidirectional balance assessment and physical maturation status in a musculoskeletal exam as both are generalizable risk factors for lower extremity injury.

Muscle Forces and Their Contributions to Vertical and Horizontal Acceleration of the Center of Mass During Sit-to-Stand Transfer in Young, Healthy Adults.

Sit-to-stand transfer is a common task that is challenging for older adults and others with musculoskeletal impairments. Associated joint torques and muscle activations have been analyzed two-dimensionally, neglecting possible three-dimensional (3D) compensatory movements in those who struggle with sit-to-stand transfer. Furthermore, how muscles accelerate an individual up and off the chair remains unclear; such knowledge could inform rehabilitation strategies. We examined muscle forces, muscleinduced accelerations, and interlimb muscle force differences during sit-to-stand transfer in young, healthy adults. Dynamic simulations were created using a custom 3D musculoskeletal model; static optimization and induced acceleration analysis were used to determine muscle forces and their induced accelerations, respectively. The gluteus maximus generated the largest force (2009.07 ± 277.31 N) and was a main contributor to forward acceleration of the center of mass (COM) (0.62 ± 0.18 m/s(2)), while the quadriceps opposed it. The soleus was a main contributor to upward (2.56 ± 0.74 m/s(2)) and forward acceleration of the COM (0.62 ± 0.33 m/s(2)). Interlimb muscle force differences were observed, demonstrating lower limb symmetry cannot be assumed during this task, even in healthy adults. These findings establish a baseline from which deficits and compensatory strategies in relevant populations (eg, elderly, osteoarthritis) can be identified.

Stride Leg Ground Reaction Forces Predict Throwing Velocity in Adult Recreational Baseball Pitchers.

Ground reaction forces produced during baseball pitching have a significant impact in the development of ball velocity. However, the measurement of only one leg and small sample sizes in these studies curb the understanding of ground reaction forces as they relate to pitching. This study aimed to further clarify the role ground reaction forces play in developing pitching velocity. Eighteen former competitive baseball players with previous high school or collegiate pitching experience threw 15 fastballs from a pitcher's mound instrumented to measure ground reaction forces under both the drive and stride legs. Peak ground reaction forces were recorded during each phase of the pitching cycle, between peak knee height and ball release, in the medial/lateral, anterior/posterior, and vertical directions, and the peak resultant ground reaction force. Stride leg ground reaction forces during the arm-cocking and arm-acceleration phases were strongly correlated with ball velocity (r2 = 0.45-0.61), whereas drive leg ground reaction forces showed no significant correlations. Stepwise linear regression analysis found that peak stride leg ground reaction force during the arm-cocking phase was the best predictor of ball velocity (r2 = 0.61) among drive and stride leg ground reaction forces. This study demonstrates the importance of ground reaction force development in pitching, with stride leg forces being strongly predictive of ball velocity. Further research is needed to further clarify the role of ground reaction forces in pitching and to develop training programs designed to improve upper extremity mechanics and pitching performance through effective force development.

Hip adductor activations during run-to-cut manoeuvres in compression shorts: implications for return to sport after groin injury.

Athletes at high risk of groin strains in sports such as hockey and soccer often choose to wear shorts with directional compression to aid in prevention of or recovery from hip adductor strains. Large, eccentric contractions are known to result in or exacerbate strain injuries, but it is unknown if these shorts have a beneficial effect on hip adductor muscle activity. In this study, surface electromyography (EMG) of the adductor longus and ground reaction force (GRF) data were obtained simultaneously on 29 healthy individuals without previous history of serious injury while performing unanticipated 45° run-to-cut manoeuvres in a laboratory setting wearing shorts with non-directional compression (control, HeatGear, Under Armour, USA) or shorts with directional compression (directional, CoreShort PRO, Under Armour, USA), in random order. Average adductor activity in the stance leg was significantly lower in the directional condition than in the control condition during all parts of stance phase (all P < 0.042). From this preliminary analysis, wearing directional compression shorts appears to be associated with reduced stance limb hip adductor activity. Athletes seeking to reduce demand on the hip adductors as they approach full return to activities may benefit from the use of directional compression shorts.

Anteromedial ridging of the femoral intercondylar notch: an anatomic study of 170 archival skeletal specimens.

PURPOSE: (1) To identify the relationship between anteromedial notch ridging, a recently identified non-contact anterior cruciate ligament injury risk factor, and patient demographics in a general population. (2) To characterize the symmetry of the femoral notch between knees. METHODS: The femoral notches of 170 non-arthritic archival skeletal specimens devoid of soft-tissue attachments (n = 79 females, 90 males, 34.3 ± 15.7 years) were measured for notch width, ridge thickness, and outlet stenosis due to ridging. Measurements were compared by race and sex by ANOVA, and Pearson correlations were calculated for all continuous measures. RESULTS: Percent stenosis was associated with increasing age (p < 0.001, r = 0.40). Ridge thickness was similar among men (2.7 ± 1.6 mm) and women (3.1 ± 1.5; n.s.). Women had narrower notches (16.0 ± 2.1 mm) and higher percent stenosis (19.6 ± 9.9 %) than men (p ≤ 0.001; men 19.3 ± 2.4 mm; 14.4 ± 8.7 %). African American men have narrower notches than Caucasian men (20.4 ± 2.5 vs. 18.7 ± 2.3 mm, respectively; p = 0.002) with no difference between women of both races (16.2 ± 2.5 vs. 15.8 ± 1.6 mm, respectively; n.s.). A positive association was observed between height and notch width among men only (18+ years men p = 0.004, r = 0.33; women n.s., r = 0.21). Finally, both total notch width and ridge thickness are symmetric between knees (p < 0.001; r = 0.98 and 0.93, respectively). CONCLUSIONS: Women have narrower femoral notches overall and also exhibit greater percent notch stenosis due to anteromedial ridging than men. Anteromedial ridging increases with age, suggesting progressive formation over time. Finally, both notch width and ridge thickness are highly symmetric between knees.

Individuals with a ventral hernia who report moderate to high fear have worse functional performance than those with low fear.

PURPOSE: Ventral hernia repairs (VHR) are performed to restore the integrity of the abdominal wall. Fear of movement, or kinesiophobia, may develop in patients with ventral hernia due to pain and functional impairments, however it has not yet been objectively measured in this patient population. The purpose of this study was to test the hypothesis that in patients with ventral hernia awaiting surgical repair, higher levels of kinesiophobia would be associated with poorer mobility, abdominal core function, and quality of life. METHODS: Seventy-seven participants scheduled for ventral hernia repair were enrolled as part of an ongoing randomized controlled trial (NCT05142618). The Tampa Scale of Kinesiophobia (TSK-11) is an 11-item questionnaire that asks about fear of movement and physical activity restriction. Participants were split into groups based on their TSK-11 score (minimal, low, moderate to high). Primary outcome measures included the five-time sit-to-stand (5xSTS), Quiet Unstable Sitting Test (QUeST), and the Hernia-Related Quality-of-Life (HerQLeS) survey. A one-way ANOVA with a Bonferroni correction compared QUeST, 5xSTS, and HerQLes results between groups. RESULTS: Groups were significantly different on 5xSTS (minimal: 11.4 ± 2.6 s, low: 13.8 ± 3.1 s, moderate to high: 17.8 ± 9.8 s; p = 0.001) and HerQLes (minimal: 58.0 ± 27.8, low: 49.4 ± 22.0, moderate to high: 30.6 ± 25.3; p = 0.003) but not QUeST (minimal: - 2.8 ± 2.5, low: - 6.8 ± 10.0, moderate to high: - 5.5 ± 5.0; p = 0.16). CONCLUSION: Individuals with moderate to high kinesiophobia have worse pre-operative performance-based (5xSTS) and self-reported (HerQLes) function and quality of life than those with minimal and low kinesiophobia. Future research should examine the influence of kinesiophobia on post-operative outcomes as it may be a potent target for rehabilitation.

Task-Related Differences in End-Point Kinematics in School-Age Children with Typical Development.

Understanding whether and how children with typical development adapt their reaches for different functional tasks could inform a more targeted design of rehabilitation interventions to improve upper extremity function in children with motor disabilities. This prospective study compares timing and coordination of a reach-to-drink, reach-to-eat, and a bilateral reaching task in typically developing school-aged children. Average speed, straightness, and smoothness of hand movements were measured in a convenience sample of 71 children, mean age 8.77 ± 0.48 years. Linear mixed models for repeated measures compared the variables by task, phases of the reach, task x phase interactions, and dominant versus non-dominant hands. There were significant main effects for task and phase, significant task x phase interactions (p < 0.05), and a significant difference between the dominant and non-dominant hand for straightness. Hand movements were fastest and smoothest for the reach-to-eat task, and least straight for the bilateral reaching task. Hand movements were also straighter in the object transport phases than the prehension and withdrawal phases. These results indicate that children with typical development change their timing and coordination of reach based on the task they are performing. These results can inform the design of rehabilitation interventions targeting arm and hand function.

ABVENTURE-P pilot trial of physical therapy versus standard of care following ventral hernia repair: Protocol for a randomized controlled trial.

Hernia disease is one of the most common reasons patients seek surgical treatment, yet nearly 1 in 4 patients seeking ventral hernia repair in the United States suffer from chronic pain, disability, and diminished physical activity. The relationships between the anterior abdominal wall, lower back, diaphragm, and pelvic floor are critical in providing function and quality of life, yet management of hernia disease has been limited to surgical restoration of anatomy without taking into consideration the functional relationships of the abdominal core. Therefore, the primary goal of this study is to evaluate the feasibility of implementing physical therapy targeted to improving stability and function in this population. A secondary goal is to estimate whether pre-operative abdominal core function predicts responsiveness to physical therapy. This study is a registry-based randomized controlled trial (NCT05142618: Pilot Trial of Abdominal Core Rehabilitation To Improve Outcomes After Ventral Hernia Repair (ABVENTURE-P)). All participants will be randomized to one of two post-operative treatment arms: standard of care plus up to 16 sessions of physical therapy, or standard of care alone. Primary timepoints include pre-operative (baseline) and ten weeks after surgery, with intermediate or secondary timepoints 30 days, 6 months, and 1 year post-operative. At each timepoint, participants will undergo functional and patient-reported outcome testing. We will also collect data on retention rate and treatment adherence. An intention to treat approach is planned for all analyses, using all participants who were randomized and have available data at the 10-week timepoint. This is a pilot and feasibility trial, hence our goals are to establish safety and initial efficacy of the PT intervention, retention and adherence to both PT and control arms, whether pre-operative abdominal core function predicts responsiveness to PT, and to collect a large enough sample to power a future definitive multi-center randomized controlled trial.

Design and cadaveric validation of a novel device to quantify knee stability during total knee arthroplasty.

The success of total knee arthroplasty depends, in part, on the ability of the surgeon to properly manage the soft tissues surrounding the joint, but an objective definition as to what constitutes acceptable postoperative joint stability does not exist. Such a definition may not exist due to lack of suitable instrumentation, as joint stability is currently assessed by visual inspection while the surgeon manipulates the joint. Having the ability to accurately and precisely measure knee stability at the time of surgery represents a key requirement in the process of objectively defining acceptable joint stability. Therefore, we created a novel sterilizable device to allow surgeons to measure varus-valgus, internal-external, or anterior-posterior stability of the knee during a total knee arthroplasty. The device can be quickly adjusted between 0 deg and 90 deg of knee flexion. The device interfaces with a custom surgical navigation system, which records the resultant rotations or translations of the knee while the surgeon applies known loads to a patient's limb with a handle instrumented with a load cell. We validated the performance of the device by having volunteers use it to apply loads to a mechanical linkage that simulated a knee joint; we then compared the joint moments calculated by our stability device against those recorded by a load cell in the simulated knee joint. Validation of the device showed low mean errors (less than 0.21 ± 1.38 Nm and 0.98 ± 3.93 N) and low RMS errors (less than 1.5 Nm and 5 N). Preliminary studies from total knee arthroplasties performed on ten cadaveric specimens also demonstrate the utility of our new device. Eventually, the use of this device may help determine how intra-operative knee stability relates to postoperative function and could lead to an objective definition of knee stability and more efficacious surgical techniques.

The influence of receiving real-time visual feedback on breathing during treadmill running to exhaustion.

Breathing plays a vital role in everyday life, and specifically during exercise it provides working muscles with the oxygen necessary for optimal performance. Respiratory inductance plethysmography (RIP) monitors breathing through elastic belts around the chest and abdomen, with efficient breathing defined by synchronous chest and abdomen movement. This study examined if providing runners with visual feedback through RIP could increase breathing efficiency and thereby time to exhaustion. Thirteen recreational runners (8F, 5M) ran to exhaustion on an inclined treadmill on two days, with visual feedback provided on one randomly chosen day. Phase angle was calculated as a measure of thoraco-abdominal coordination. Time to exhaustion was not significantly increased when visual feedback was provided (p = 1). Phase angle was not significantly predicted by visual feedback (p = 0.667). Six participants improved phase angle when visual feedback was provided, four of whom increased time to exhaustion. Four participants improved phase angle by 9° or more, three of whom increased time to exhaustion. Participants who improved phase angle with visual feedback highlight that improving phase angle could increase time to exhaustion. Greater familiarization with breathing techniques and visual feedback and a different paradigm to induce running fatigue are needed to support future studies of breathing in runners.

Discover your potential: The influence of kinematics on a muscle's ability to contribute to the sit-to-stand transfer.

Existing methods for estimating how individual muscles contribute to a movement require extensive time and experimental resources. In this study we developed an efficient method for determining how changes to lower extremity joint kinematics affect the potential of individual muscles to contribute to whole-body center-of-mass vertical (support) and anteroposterior (progression) accelerations. A 4-link 2-dimensional model was used to assess the effect of kinematic changes on muscle function. Joint kinematics were systematically varied throughout ranges observed during the momentum transfer phase of the sit-to-stand transfer. Each muscle's potential to contribute to support and progression was computed and compared to simulated potentials estimated by traditional dynamic simulation methods for young adults and individuals with knee osteoarthritis. The new method required 4-10s to compute muscle potentials per kinematic state and computed potentials were consistent with simulated potentials. The new method identified differences in muscle potentials between groups due to kinematic differences, particularly decreased anterior pelvic tilt in young adults, and revealed kinematic and muscle strengthening modifications to increase support. The methods presented provide an efficient, systematic approach to evaluate how joint kinematic adjustments alter a muscle's ability to contribute to movement and can identify potential sources of pathologic movement and rehabilitation strategies.

Is modular control related to functional outcomes in individuals with knee osteoarthritis and following total knee arthroplasty?

BACKGROUND: Individuals who undergo total knee arthroplasty (TKA) for treatment of knee osteoarthritis often experience suboptimal outcomes. Investigation of neuromuscular control strategies in these individuals may reveal factors that contribute to these functional deficits. The purpose of this pilot study was to determine the relationship between patient function and modular control during gait before and after TKA. METHODS: Electromyography data from 36 participants (38 knees) were collected from 8 lower extremity muscles on the TKA-involved limb during ≥5 over-ground walking trials before (n = 30), 6-months after (n = 26), and 24-months after (n = 13) surgery. Muscle modules were estimated using non-negative matrix factorization. The number of modules was determined from 500 resampled trials. RESULTS: A higher number of modules was related to better performance-based and patient-reported function before and 6-months after surgery. Participants with organization similar to healthy, age-matched controls trended toward better function 24-months after surgery, though these results were not statistically significant. We also observed plasticity in the participants' modular control strategies, with 100% of participants who were present before and 24-months after surgery (10/10) demonstrating changes in the number of modules and/or organization of at least 1 module. CONCLUSIONS: This pilot work suggests that functional improvements following TKA may initially present as increases in the number of modules recruited during gait. Subsequent improvements in function may present as improved module organization. NOTEWORTHY: This work is the first to characterize motor modules in TKA both before and after surgery and to demonstrate changes in the number and organization of modules over the time course of recovery, which may be related to changes in patient function. The plasticity of modular control following TKA is a key finding which has not been previously documented and may be useful in predicting or improving surgical outcomes through novel rehabilitation protocols.

A Quiet Unstable Sitting Test to quantify core stability in clinical settings: Application to adults with ventral hernia.

BACKGROUND: The abdominal core is comprised of the diaphragm, abdominal wall, and pelvic floor, and serves several important functions for balance, movement, and strength. Injury to this area, such as hernia, can have substantial impact. The Quiet Unstable Sitting Test involves individuals seated on the rounded surface of a BOSU® balance trainer placed on top of a force plate and situated on a flat, elevated surface. METHODS: An ordinal Quiet Unstable Sitting Test core stability score was calculated from center of pressure measurements, with 0 representing "normal" and < 0 indicating worsening stability. Hernia-Related Quality of Life survey summary scores were assessed (higher scores indicating better quality). FINDINGS: A developmental cohort of 32 was used to establish reliability and normative values for the Quiet Unstable Sitting Test. A control group of 32 participants (43.7 ± 16.2 yrs., BMI 29.0 ± 4.9, 66% Female) was then compared to 21 patients with hernia (56.2 ± 12.5 yrs., BMI 29.2 ± 6.3, 24% Female). Hernia patients had median composite score of -2 and median quality of life score of 66, versus median Quiet Unstable Sitting Test of -0.5 and median quality of life of 93 for controls (p ≤ 0.01). Quality of life and Quiet Unstable Sitting Test scores were not correlated (p > 0.05). INTERPRETATION: Hernia patients demonstrated significantly worse core stability and quality of life. These assessments were independent of one another across the entire population, indicating each measure's unique constructs of patient function. Core stability can be reliably measured in a clinical setting and may help with patient activation and rehabilitation.

Comparative assessment of bone pose estimation using Point Cluster Technique and OpenSim.

Estimating the position of the bones from optical motion capture data is a challenge associated with human movement analysis. Bone pose estimation techniques such as the Point Cluster Technique (PCT) and simulations of movement through software packages such as OpenSim are used to minimize soft tissue artifact and estimate skeletal position; however, using different methods for analysis may produce differing kinematic results which could lead to differences in clinical interpretation such as a misclassification of normal or pathological gait. This study evaluated the differences present in knee joint kinematics as a result of calculating joint angles using various techniques. We calculated knee joint kinematics from experimental gait data using the standard PCT, the least squares approach in OpenSim applied to experimental marker data, and the least squares approach in OpenSim applied to the results of the PCT algorithm. Maximum and resultant RMS differences in knee angles were calculated between all techniques. We observed differences in flexion/extension, varus/valgus, and internal/external rotation angles between all approaches. The largest differences were between the PCT results and all results calculated using OpenSim. The RMS differences averaged nearly 5° for flexion/extension angles with maximum differences exceeding 15°. Average RMS differences were relatively small (< 1.08°) between results calculated within OpenSim, suggesting that the choice of marker weighting is not critical to the results of the least squares inverse kinematics calculations. The largest difference between techniques appeared to be a constant offset between the PCT and all OpenSim results, which may be due to differences in the definition of anatomical reference frames, scaling of musculoskeletal models, and/or placement of virtual markers within OpenSim. Different methods for data analysis can produce largely different kinematic results, which could lead to the misclassification of normal or pathological gait. Improved techniques to allow non-uniform scaling of generic models to more accurately reflect subject-specific bone geometries and anatomical reference frames may reduce differences between bone pose estimation techniques and allow for comparison across gait analysis platforms.

Lumbopelvic control and pitching performance of professional baseball pitchers.

This study assessed the correlation between lumbopelvic control during a single-leg balancing task and in-game pitching performance in Minor-League baseball pitchers. Seventy-five healthy professional baseball pitchers performed a standing lumbopelvic control test during the last week of spring training for the 2008 and 2009 seasons while wearing a custom-designed testing apparatus, the "Level Belt." With the Level Belt secured to the waist, subjects attempted to transition from a 2-leg to a single-leg pitching stance and balance while maintaining a stable pelvic position. Subjects were graded on the maximum sagittal pelvic tilt from a neutral position during the motion. Pitching performance, number of innings pitched (IP), and injuries were compared for all subjects who pitched at least 50 innings during a season. The median Level Belt score for the study group was 7°. Two-sample t-tests with equal variances were used to determine if pitchers with a Level Belt score <7° or ≥7° were more likely to perform differently during the baseball season, and chi-square analysis was used to compare injuries between groups. Subjects scoring <7° on the Level Belt test had significantly fewer walks plus hits per inning than subjects scoring ≥7° (walks plus hits per inning pitched, 1.352 ± 0.251 vs. 1.584 ± 0.360, p = 0.013) and significantly more IP during the season (IP, 78.89 ± 38.67 vs. 53.38 ± 42.47, p = 0.043). There was no significant difference in the number of pitchers injured between groups. These data suggest that lumbopelvic control influences overall performance for baseball pitchers and that a simple test of lumbopelvic control can potentially identify individuals who have a better chance of pitching success.

Effects of spinal coupling and marker set on tracking of spine models during running.

Despite the wide-spread use of musculoskeletal simulations and its use in estimating spinal loads, much is not known about how to best collect experimental data for modelling purposes. The primary purposes in this study were to determine the effects of tracking of running motion capture data to a model (1) with and without coupling of lumbar spine segments, and (2) with varying combinations of spinal markers. Running trials were collected from 7 participants, with each at three different speeds. The motion data was fit to the Full-Body Lumbar Spine Model (FBLS) with coupling of the lumbar spine enabled (CS) and disabled and therefore rigid (RS) in OpenSim through the Inverse Kinematics tool (IK). Different combinations of markers were chosen as tracking inputs for IK to represent experimental data collection with different marker sets. Root-mean-square (RMS) marker errors of all 13 markers along the spine for each gait cycle were calculated. The CS model resulted in 23.7% lower errors than the RS model (p < 0.001). The marker subset analysis showed that increasing the number of markers in the experimental data collection decreases the error, with the four marker tracking subsets with the highest number of markers tracked having the lowest errors. The location of the marker and timing in the gait cycle did not affect marker error. When spinal mechanics are of interest, the inclusion of a coupled lumbar spine in the model and a larger spinal marker set help better track experimental kinematics when fitting to a model.