Systematic Selection of Key Logistic Regression Variables for Risk Prediction Analyses: A Five-Factor Maximum Model.

GENERAL AND CRITICAL REVIEW FORMAT: The evolution of clinical practice and medical technology has yielded an increasing number of clinical measures and tests to assess a patient's progression and return to sport readiness after injury. The plethora of available tests may be burdensome to clinicians in the absence of evidence that demonstrates the utility of a given measurement. OBJECTIVE: Thus, there is a critical need to identify a discrete number of metrics to capture during clinical assessment to effectively and concisely guide patient care. DATA SOURCES: The data sources included Pubmed and PMC Pubmed Central articles on the topic. Therefore, we present a systematic approach to injury risk analyses and how this concept may be used in algorithms for risk analyses for primary anterior cruciate ligament (ACL) injury in healthy athletes and patients after ACL reconstruction. MAIN RESULTS: In this article, we present the five-factor maximum model, which states that in any predictive model, a maximum of 5 variables will contribute in a meaningful manner to any risk factor analysis. CONCLUSIONS: We demonstrate how this model already exists for prevention of primary ACL injury, how this model may guide development of the second ACL injury risk analysis, and how the five-factor maximum model may be applied across the injury spectrum for development of the injury risk analysis.

Refractory Ulnar Nerve Symptoms in an Adolescent Pitcher With Medial Apophysitis.

A 16-year-old high school baseball pitcher with a 3-week history of acute-onset pain in his medial elbow during throwing presented to physical therapy. Following examination, physical therapy was initiated and the patient was referred for imaging, with suspicion of ulnar collateral ligament (UCL) injury. Radiographs were noncontributory. Ultrasound imaging, however, was performed by a physiatrist and was suggestive of a partial-thickness tear of the UCL and ulnar nerve enlargement. The physiatrist ordered magnetic resonance imaging, which confirmed a medial apophyseal stress reaction, a mild UCL sprain, and reactive ulnar nerve edema. J Orthop Sports Phys Ther 2018;48(5):419. doi:10.2519/jospt.2018.7359.

Patient-Reported and Objectively Measured Function Before and After Reverse Shoulder Arthroplasty.

BACKGROUND AND PURPOSE: Documenting functional outcomes after reverse shoulder arthroplasty (RSA) is critical to advancing patient care. The interplay been self-reported and objectively measured outcome measures has not been widely described. The utilization of wearable devices to document upper extremity limb activity is a new approach for objectively measuring outcomes. Therefore, the purpose of this study was to evaluate changes in pain, and self-reported function and objectively measured limb activity after RSA. We also assessed the influence of pain on self-reported function and objectively measured limb activity to determine the impact of pain on outcomes after RSA. MATERIALS: This study implemented a prospective, repeated-measures design. Fourteen patients undergoing RSA underwent testing before surgery, and 2 and 12 months after surgery. Patient-reported instruments included pain, Disabilities of Arm, Shoulder and hands (DASH), and physical component summary (PCS) of the 36-Item Short Form Health Survey. Objective limb activity (mean activity value, m/s/min epoch; inactive time, %; low activity, %; and high activity, %) was captured with triaxial accelerometers worn on the upper and lower arm. A repeated-measures ANOVA tested for differences across time. The Spearman rank-order correlation was calculated to evaluate the influence of pain on DASH, PCS scores, and mean limb activity. RESULTS: Patient-reported measures improved after surgery (pain, P < .01; DASH, P < .01; PCS, P = .01). No change in limb activity was found at 1 year compared with preoperative values for mean (forearm, P = 1.00; arm, P = .36), inactivity (forearm, P = .33; arm, P = .22), low (forearm, P = .77; arm, P = .11) or high (forearm, P = 1.00; arm, P = .20) activity. There was a relationship between pain and DASH scores 1 year after surgery (P = .04) but not before surgery (P = .16), or 2 months after surgery (P = .30). There was no relationship between pain and PCS scores at any time point (preoperative, P = .97; 2 months, P = .21; 1 year, P = .08) nor pain and limb activity (forearm: preoperative, P = .36; 2 months, P = .67; 1 year, P = .16; arm: preoperative, P = .97; 2 months, P = .59; 1 year, P = .51). CONCLUSIONS: RSA reduced pain and enhanced patient-perceived function. Objectively measured upper extremity limb activity is not different 1 year after surgery compared with preoperative levels. LEVEL OF EVIDENCE: III.

Ununited Bone Ossicle in a Patient With Patellar Tendinopathy.

A 40-year-old man presented to a physician for knee pain when squatting and in resisted knee extension. The initial diagnosis was patellar tendinopathy. Following physical therapy treatment, a sports medicine physician was consulted for a second opinion. Radiography, diagnostic ultrasound, and magnetic resonance imaging were performed, confirming the original diagnosis and revealing Hoffa's fat pad impingement secondary to an ununited ossicle. J Orthop Sports Phys Ther 2017;47(11):885. doi:10.2519/jospt.2017.7443.

Novel approaches to objectively assess shoulder function.

BACKGROUND: The purpose of this study was to evaluate the effectiveness of existing technologies implemented in a novel manner to objectively capture upper extremity function. MATERIALS AND METHODS: Patients scheduled to undergo reverse shoulder arthroplasty were recruited for the study. Functional limb use was measured with triaxial accelerometers worn in the subjects' natural living environment. Functional reach area was captured by 3-dimensional motion analysis testing as subjects were asked to circumduct their limb, reaching as far as possible in a circular manner. Statistical testing (α ≤ .05) was performed by paired t tests to identify differences between limbs. RESULTS: There was no difference in functional limb activity between sides for the lower (P = .497) or upper arm (P = .918) for inactivity time. Mean activity was greater for the uninvolved limb compared with the involved limb (lower arm, P = .045; upper arm, P = .005). Low-intensity activity was greater for the involved arm compared with the uninvolved arm (lower arm, P = .007; upper arm, P = .015), whereas high-intensity activity was greater for the uninvolved arm (lower arm, P = .013; upper arm, P = .005). Radius of the functional reach area was greater for the uninvolved limb compared with the involved limb (P = .006). CONCLUSIONS: Novel methods of capturing function were effective in discerning differences in side-to-side abilities among patients scheduled to undergo reverse shoulder arthroplasty. These testing procedures may be used to capture function across a spectrum of shoulder diseases. These objective data are invaluable in assessing the impact of disease and recovery after intervention and obtaining reimbursement from third-party payers.

Accelerations of the waist and lower extremities over a range of gait velocities to aid in activity monitor selection for field-based studies.

This study aimed to define accelerations measured at the waist and lower extremities over a range of gait velocities to provide reference data for choosing the appropriate accelerometer for field-based human activity monitoring studies. Accelerations were measured with a custom activity monitor (± 16g) at the waist, thighs, and ankles in 11 participants over a range of gait velocities from slow walking to running speeds. The cumulative frequencies and peak accelerations were determined. Cumulative acceleration amplitudes for the waist, thighs, and ankles during gait velocities up to 4.8 m/s were within the standard commercial g-range (± 6g) in 99.8%, 99.0%, and 96.5% of the data, respectively. Conversely, peak acceleration amplitudes exceeding the limits of many commercially available activity monitors were observed at the waist, thighs, and ankles, with the highest peaks at the ankles, as expected. At the thighs, and more so at the ankles, nearly 50% of the peak accelerations would not be detected when the gait velocity exceeds a walking velocity. Activity monitor choice is application specific, and investigators should be aware that when measuring high-intensity gait velocity activities with commercial units that impose a ceiling at ± 6g, peak accelerations may not be measured.

Tri-axial accelerometer analysis techniques for evaluating functional use of the extremities.

UNLABELLED: Activity monitors provide an objective mechanism for evaluating patient function. It is unclear what similarities or unique information may be yielded using different analyses. Fifteen patients scheduled to undergo shoulder arthroplasty and fifteen matched control subjects wore tri-axial accelerometer activity monitors bilaterally at the lower (wrist) and upper (biceps) arm for 3days. Measures of central tendency, variance, sample entropy, and asymmetry were calculated. A novel technique to evaluate time distribution of activity intensity was also performed. Within both groups there was a difference in central tendency and variance when comparing dominant and non-dominant limbs for both the lower ( CONTROLS: Mean Activity, P<0.001; Max Activity, P<0.001; PATIENTS: Mean Activity, P=0.044; Max Activity, P=0.009) and upper ( CONTROLS: Mean Activity, P<0.001; Max Activity, P=0.046; PATIENTS: Mean Activity, P=0.002; Max Activity, P=0.049) arm. Within group differences were also present for lower arm entropy in both groups (CONTROLS, P<0.001; PATIENTS P=0.041), and at the upper arm for patients (P=0.003). There were differences between groups for the asymmetry index for both the lower (P=0.033) and upper arm (P=0.005), and maximum activity level of the lower arm (P=0.05). Between group differences were present for time distribution of activity intensity, as the involved upper arm of patients was inactive for a greater time than controls (P=0.013). These results highlight unique information provided by multiple analysis methods, and include a novel approach of evaluating the distribution of time spent across variable intensity activities.

Pitch velocity is a predictor of medial elbow distraction forces in the uninjured high school-aged baseball pitcher.

BACKGROUND: Medial elbow injuries are common among baseball pitchers. Easily accessed methods to assess medial elbow stress may be useful in identifying individuals with increased injury risk. HYPOTHESIS: Pitch velocity (PV) is positively associated with higher medial elbow adduction moments. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: Participants included 26 uninjured high school pitchers, 15 to 18 years in age. Three-dimensional data and PV were collected as athletes threw 10 fastballs for strikes to a regulation-distance target. Variables of interest were the normalized peak internal elbow adduction moment and peak PV. Linear regression was performed to evaluate the influence of PV on the adduction moment. RESULTS: For the group, mean PV was 71 mph (range, 58-81 mph), and the adduction moment was 0.558 Nm/Ht × mass (range, 0.378-0.723). PV was positively associated with the adduction moment (P < 0.01, R(2)= 0.373). CONCLUSIONS: Talented young pitchers may be more susceptible to elbow injuries as a consequence of a biomechanical coupling between PV and upper extremity joint moments. CLINICAL RELEVANCE: PV may be measured easily and serve as an indicator of medial elbow stress.

Glenohumeral rotational motion and strength and baseball pitching biomechanics.

CONTEXT: Addressing loss of shoulder range of motion and rotator cuff weakness in injury-prevention programs might be an effective strategy for preventing throwing arm injuries in baseball pitchers. However, the influence of these clinical measures on pitching biomechanics is unclear. OBJECTIVE: To evaluate the relationships among clinical measures of shoulder rotational motion and strength and 3-dimensional pitching biomechanics and to evaluate the presence of coupling between the shoulder and the elbow during pitching to provide insight into the influence of clinical shoulder characteristics on elbow biomechanics. DESIGN: Cross-sectional study. SETTING: Biomechanics laboratory. PATIENTS OR OTHER PARTICIPANTS: A total of 27 uninjured male high school baseball pitchers (age = 16 ± 1.1 years, height = 183 ± 7 cm, mass = 83 ± 12 kg). MAIN OUTCOME MEASURE(S): Clinical measures included shoulder internal- and external-rotation range of motion and peak isometric internal- and external-rotator strength. Three-dimensional upper extremity biomechanics were assessed as participants threw from an indoor pitching mound to a target at regulation distance. Linear regressions were used to assess the influence of clinical measures on the peak shoulder internal and external rotation moments and the peak elbow-adduction moment. RESULTS: We found a positive relationship between clinically measured internal-rotator strength and shoulder external-rotation moment (R(2) = 0.181, P = .04) during pitching. We also noted an inverse relationship between clinically measured external-rotation motion and the elbow-adduction moment (R(2) = 0.160, P = .04) and shoulder internal-rotation moment (R(2) = 0.250, P = .008) during pitching. We found a positive relationship between peak shoulder internal-rotation moment and the peak elbow-adduction moment (R(2) = 0.815, P < .001) during pitching. CONCLUSIONS: This study provides insight into the effects of shoulder strength and motion on pitching biomechanics and how these clinical measures might contribute to throwing arm injuries in the baseball pitcher. A relationship also was identified between peak shoulder and elbow moments in the throwing arm during pitching, providing biomechanical support for addressing clinical shoulder characteristics as a potential strategy for preventing elbow injury.

Voluntary activation deficits of the infraspinatus present as a consequence of pitching-induced fatigue.

HYPOTHESIS: Neuromuscular inhibition of the infraspinatus would be greater and external rotation muscle force would be lower after a simulated game compared with pregame values. MATERIALS AND METHODS: The sample included 21 uninjured, asymptomatic high school-aged baseball pitchers. Maximum volitional shoulder external rotation strength was assessed before and after a simulated game with a clinical dynamometer. Voluntary activation of the infraspinatus was assessed during strength testing by a modified burst superimposition technique. Performance-related fatigue was assessed by monitoring pitch velocity, and global fatigue was assessed by subject self-report before and after the game. Statistical testing included paired and independent t tests, with α ≤ .05. RESULTS: There was no difference between throwing and non-throwing shoulder external rotation strength (P = .12) or voluntary infraspinatus activation (P = .27) before the game. After the game, voluntary activation was significantly lower in the throwing limb compared with pregame activation levels (P = .01). Lower external rotation strength after the game approached statistical significance (P = .06). Pitch velocity was lower in the final inning compared with first-inning velocity (P = .01), and fatigue was significantly greater after the game (P = .01). CONCLUSIONS: Voluntary infraspinatus muscle activation is a mechanism contributing to external rotation muscle weakness in the fatigued pitcher. Understanding mechanisms contributing to muscle weakness is necessary to develop effective injury prevention and rehabilitation programs. Treatment techniques that enhance neuromuscular activation may be a useful strategy for enhancing strength in this population.

The effects of anthropometric scaling parameters on normalized muscle strength in uninjured baseball pitchers.

CONTEXT: Muscle force must be normalized for between-subjects comparisons of strength to be valid. The most effective method for normalizing muscle strength has not, however, been systematically evaluated. OBJECTIVE: To evaluate the effects of normalizing muscle strength using a spectrum of anthropometric parameters. DESIGN: Cross-sectional. SETTING: Laboratory. PARTICIPANTS: 50 uninjured high-school-age baseball pitchers. INTERVENTIONS: Shoulder-rotation strength was tested at 0° and 90° abduction with a handheld dynamometer. Muscle force was normalized to parameters including subject height, weight, height × weight, body-mass index (BMI), forearm length, and forearm length × height. OUTCOME MEASURES: Statistical analysis included evaluating the coefficient of variation, skewness, and kurtosis of the nonnormalized and normalized muscle force. The most effective normalization method was determined based on the scaling factor that yielded the lowest variability for the data set and promoted the most normal distribution of the data set. RESULTS: Using body weight to scale muscle force was the most effective anthropometric parameter for normalizing strength values based on the group of statistical measures of variability. BMI, height × weight, and forearm length × weight as scaling factors also yielded less variable values for muscle strength compared with nonnormalized strength, but less consistently than body weight. Height and forearm length were least effective in reducing the variability of the data set relative to nonnormalized muscle force. CONCLUSION: This study provides objective support for scaling muscle strength to subject body weight. This approach to normalizing muscle strength uses methods readily accessible to clinicians and researchers and may facilitate the identification of differences in strength between individuals with diverse physical characteristics.

A profile of glenohumeral internal and external rotation motion in the uninjured high school baseball pitcher, part II: strength.

CONTEXT: A database describing the range of normal rotator cuff strength values in uninjured high school pitchers has not been established. Chronologic factors that contribute to adaptations in strength also have not been established. OBJECTIVES: To establish a normative profile of rotator cuff strength in uninjured high school baseball pitchers and to determine whether bilateral differences in rotator cuff strength are normal findings in this age group. DESIGN: Cohort study. SETTING: Baseball playing field. PATIENTS OR OTHER PARTICIPANTS: A total of 165 uninjured male high school baseball pitchers (age = 16 ± 1 years, height=1.8±0.1 m, mass=76.8±10.1 kg, pitching experience =7±2 years). MAIN OUTCOME MEASURE(S): Isometric rotator cuff strength was measured bilaterally with a handheld dynamometer. We calculated side-to-side differences in strength (external rotation [ER], internal rotation [IR], and the ratio of ER:IR at 90° of abduction), differences in strength by age, and the influence of chronologic factors (participant age, years of pitching experience) on limb strength. RESULTS: Side-to-side differences in strength were found for ER, IR, and ER:IR ratio at 90° of abduction. Age at the time of testing was a significant but weak predictor of both ER strength (R(2)=0.032, P = .02) and the ER:IR ratio (R(2)=0.051 , P = .004) at 90° of abduction. CONCLUSIONS: We established a normative profile of rotator cuff strength for the uninjured high school baseball pitcher that might be used to assist clinicians and researchers in the interpretation of muscle strength performance in this population. These data further suggested that dominant-limb adaptations in rotator cuff strength are a normal finding in this age group and did not demonstrate that these adaptations were a consequence of the age at the time of testing or the number of years of pitching experience.

A profile of glenohumeral internal and external rotation motion in the uninjured high school baseball pitcher, part I: motion.

CONTEXT: The magnitude of motion that is normal for the throwing shoulder in uninjured baseball pitchers has not been established. Chronologic factors contributing to adaptations in motion present in the thrower's shoulder also have not been established. OBJECTIVES: To develop a normative profile of glenohumeral rotation motion in uninjured high school baseball pitchers and to evaluate the effect of chronologic characteristics on the development of adaptations in shoulder rotation motion. DESIGN: Cohort study. SETTING: Baseball playing field. PATIENTS OR OTHER PARTICIPANTS: A total of 210 uninjured male high school baseball pitchers (age = 16 ± 1.1 years, height=1.8±0.1 m, mass=77.5±11.2 kg, pitching experience=6±2.3 years). INTERVENTION(S): Using standard goniometric techniques, we measured passive rotational glenohumeral range of motion bilaterally with participants in the supine position. MAIN OUTCOME MEASURE(S): Paired t tests were performed to identify differences in motion between limbs for the group. Analysis of variance and post hoc Tukey tests were conducted to identify differences in motion by age. Linear regressions were performed to determine the influence of chronologic factors on limb motion. RESULTS: Rotation motion characteristics for the population were established. We found no difference between sides for external rotation (ER) at 0° of abduction (t(209) = 0.658, P = .51), but we found side-to-side differences in ER (t(209) =-13.012,P < .001) and internal rotation (t(209) =15.304, P < .001) at 90° of abduction. Age at the time of testing was a significant negative predictor of ER motion for the dominant shoulder (R(2) = 0.019, P = .049) because less ER motion occurred at the dominant shoulder with advancing age. We found no differences in rotation motion in the dominant shoulder across ages (F(4,205) range, 0.451-1.730,P > .05). CONCLUSIONS: This range-of-motion profile might be used to assist with the interpretation of normal and atypical shoulder rotation motion in this population. Chronologic characteristics of athletes had no influence on range-of-motion adaptations in the thrower's shoulder.

Relationship between the medial elbow adduction moment during pitching and ulnar collateral ligament appearance during magnetic resonance imaging evaluation.

BACKGROUND: Medial elbow distraction during pitching as the primary mechanism contributing to adaptations in ulnar collateral ligament (UCL) appearance during magnetic resonance imaging (MRI) evaluation has not been established. HYPOTHESIS: Uninjured high school-aged pitchers with unilateral adaptations of the UCL exhibit a higher peak internal elbow adduction moment than those without UCL adaptations. STUDY DESIGN: Cohort study (Prevalence); Level of evidence, 2. METHODS: Twenty uninjured, asymptomatic high school-aged pitchers underwent bilateral elbow MRI examinations. Three-dimensional motion analysis testing was performed to collect throwing arm biomechanics as participants pitched from an indoor mound. Nonparametric tests were performed to compare peak internal elbow adduction moment in uninjured participants with and without adaptations in UCL appearance and to determine the nature of the relationship between the peak internal adduction moment and UCL appearance. RESULTS: Uninjured participants with UCL thickening exhibited a higher peak internal elbow adduction moment of 53.3 ± 6.8 N·m compared with uninjured participants without adaptations in UCL appearance, 38.8 ± 10.9 N·m (P = .05), as higher moments were correlated with ligament thickening (correlation coefficient, 0.45) (P = .02). CONCLUSION: This study establishes the association between medial elbow distraction captured by the internal adduction moment during pitching and UCL adaptations visible during MRI evaluation.

Magnetic resonance imaging of the throwing elbow in the uninjured, high school-aged baseball pitcher.

BACKGROUND: Tissue adaptations in response to pitching are an expected finding during magnetic resonance imaging (MRI) evaluation of the throwing elbow of adult pitchers. These changes are considered normal in the absence of symptom complaints. It is unclear when during the playing career these tissue adaptations are initiated. HYPOTHESIS: Abnormalities in the appearance of the throwing elbow compared with the nonthrowing elbow would be visible during MRI assessment of this asymptomatic population of high school-aged throwers. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Twenty-three uninjured, asymptomatic male high school-aged baseball pitchers (mean age, 16 years) with no history of elbow injury were recruited for the study. Participants had a minimum of 3 years' experience with pitching as their primary position (mean experience, 6 years). Bilateral elbow MRI examinations were performed using a standardized protocol including fast spin-echo proton-density (axial and coronal), T1-weighted (sagittal), and T2-weighted fat-saturated (axial, sagittal, and coronal) sequences. Osteoarticular, ligamentous, musculotendinous, and neural structures were evaluated and compared bilaterally. The images were reviewed by a musculoskeletal radiologist who was blinded to all the gathered data on these athletes, including limb dominance. RESULTS: Three participants (13%) had no abnormalities. Fifteen individuals (65%) had asymmetrical anterior band ulnar collateral ligament thickening, including 4 individuals who also had mild sublime tubercle/anteromedial facet edema. Fourteen participants (61%) had posteromedial subchondral sclerosis of the ulnotrochlear articulation, including 8 (35%) with a posteromedial ulnotrochlear osteophyte, and 4 (17%) with mild posteromedial ulnotrochlear chondromalacia. Ten individuals (43%) had multiple abnormal findings in the throwing elbow. CONCLUSION: Thickening of the anterior band of the ulnar collateral ligament and posteromedial subchondral sclerosis of the trochlea are common findings in the high school-aged pitcher and may be considered normal clinical findings in the absence of symptom complaints. Other changes in tissue appearance of the throwing elbow are uncommon in this age group and should be regarded with a higher level of caution when evaluating for the presence of injury. An understanding of the MRI appearance of the uninjured youth pitcher is necessary for clinicians to distinguish between normal adaptations and the presence of injury.

Comparison of shoulder range of motion, strength, and playing time in uninjured high school baseball pitchers who reside in warm- and cold-weather climates.

BACKGROUND: There is an assumption that baseball athletes who reside in warm-weather climates experience larger magnitude adaptations in throwing shoulder motion and strength compared with their peers who reside in cold-weather climates. HYPOTHESES: (1) The warm-weather climate (WWC) group would exhibit more pronounced shoulder motion and strength adaptations than the cold-weather climate (CWC) group, and (2) the WWC group would participate in pitching activities for a greater proportion of the year than the CWC group, with the time spent pitching predicting throwing shoulder motion and strength in both groups. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: One hundred uninjured high school pitchers (50 each WWC, CWC) were recruited. Rotational shoulder motion and isometric strength were measured and participants reported the number of months per year they pitched. To identify differences between groups, t tests were performed; linear regression was used to determine the influence of pitching volume on shoulder motion and strength. RESULTS: The WWC group pitched more months per year than athletes from the CWC group, with the number of months spent pitching negatively related to internal rotation motion and external rotation strength. The WWC group exhibited greater shoulder range of motion in all planes compared with the CWC group, as well as significantly lower external rotation strength and external/internal rotation strength ratios. There was no difference in internal rotation strength between groups, nor a difference in the magnitude of side-to-side differences for strength or motion measures. CONCLUSION: Athletes who reside in cold- and warm-weather climates exhibit differences in throwing shoulder motion and strength, related in part to the number of months spent participating in pitching activities. The amount of time spent participating in pitching activities and the magnitude of range of motion and strength adaptations in athletes who reside in warm-weather climates may make these athletes more susceptible to throwing-related injuries.

Comparative biomechanical effectiveness of over-the-counter devices for individuals with a flexible flatfoot secondary to forefoot varus.

OBJECTIVES: Evaluate effects of a new off-the-shelf insert on frontal plane foot biomechanics and compare effectiveness of the new and an existing off-the-shelf insert and a motion-control shoe in neutralizing frontal plane foot biomechanics. DESIGN: Descriptive. SETTING: Biomechanics laboratory. PARTICIPANTS: Fifteen uninjured subjects with a flexible flatfoot secondary to forefoot varus. ASSESSMENT OF RISK FACTORS: Three-dimensional kinematic and kinetic data were collected as subjects walked and jogged at their self-selected speed while wearing a motion-control running shoe, the shoe with a new off-the-shelf insert, and the shoe with an existing off-the-shelf insert. MAIN OUTCOME MEASURES: Frontal plane kinematics and rearfoot kinetics were evaluated during stance. Statistical analysis was performed using a repeated measures analysis of variance and Student-Newman-Keuls post hoc tests (α ≤ 0.05). RESULTS: The new insert and motion-control shoe placed the forefoot in a less-everted position than the existing off-the-shelf insert during walking. There were no differences in forefoot kinematics during jogging, nor were there differences in rearfoot motion during walking or jogging. The rearfoot eversion moment was significantly lower with the new off-the-shelf insert compared with the motion-control shoe and the existing insert during walking and jogging. CONCLUSIONS: A new off-the-shelf device is available that promotes more neutral frontal plane biomechanics, thus providing a theoretical rationale for using this device for injury prevention and treatment. The comparative biomechanical effectiveness of a motion-control shoe and the orthotic inserts may assist health care professionals in selecting a device to correct the flatfoot structure.

Shoulder demands in manual wheelchair users across a spectrum of activities.

OBJECTIVE: Investigate shoulder joint kinetics over a range of daily activity and mobility tasks associated with manual wheelchair propulsion to characterize demands placed on the shoulder during the daily activity of manual wheelchair users. DESIGN: Case series. SUBJECTS: Twelve individuals who were experienced manual wheelchair users. METHODS: Upper extremity kinematics and handrim wheelchair kinetics were measured over level propulsion, ramp propulsion, start and stop over level terrain, and a weight relief maneuver. Shoulder intersegmental forces and moments were calculated from inverse dynamics for all conditions. RESULTS: Weight relief resulted in significantly higher forces and ramp propulsion resulted in significantly higher moments than the other conditions. Surprisingly, the start condition resulted in large intersegmental moments about the shoulder equivalent with that of the ramp propulsion, while the demand imparted by the stop condition was shown to be equivalent to level propulsion across all forces and moments. CONCLUSIONS: This study provides characterization of daily living and mobility activities associated with manual wheelchair propulsion not previously reported and identifies activities that result in higher shoulder kinetics when compared to standard level propulsion.

Upper-limb joint kinetics expression during wheelchair propulsion.

In the wheelchair propulsion literature, it is common to report upper-limb (UL) joint kinetics to express shoulder, elbow, and wrist loads. Choosing the appropriate kinetic resolution coordinate system (CS) for UL joint forces and moments has become a laboratory-specific process. The differences that arise during interpretation may hinder a clear and broad understanding of UL joint kinetics during wheelchair propulsion. This article addresses the inconsistency of kinetic reporting in the wheelchair literature that examines the pain and injury experienced by manual wheelchair users. To highlight the variety of reporting methods in wheelchair propulsion, this article surveys peer-reviewed, published articles reporting wrist-, elbow-, or shoulder-joint intersegmental forces and moments calculated from inverse dynamics during wheelchair propulsion. To correct this inconsistency, researchers may need to standardize kinetic reporting methods to achieve a cohesive comprehension of wheelchair biomechanics. This article is provided to open discussion on the anatomical and clinical relevance of currently employed CSs and other available options, with the additional goal of providing an initial recommendation for kinetic representation during wheelchair propulsion.

Wheelchair propulsion demands during outdoor community ambulation.

OBJECTIVE: Quantify manual wheelchair propulsion effort during outdoor community ambulation. DESIGN: Case series. SUBJECTS: Thirteen individuals (12 with SCI, 1 with spina bifida) who were experienced manual wheelchair users and had no current upper extremity injury or pain complaints. METHODS: Measurements were obtained from instrumented wheelchair rims during steady-state propulsion as subjects traversed outdoor concrete sidewalk terrain that included smooth level, aggregate level, and a ramp with a smooth surface. Propulsion effort was assessed using the average propulsion moment, average instantaneous power, and work for both upper extremities. RESULTS: Propulsion effort, captured by the propulsion moment, work and power, varied across ground conditions (p<0.001). Propulsion effort was greater as the rolling resistance increased (i.e., smooth versus aggregate surfaces) and as the inclination angle progressed from level to inclined surfaces. There were no side-to-side differences across ground conditions for the propulsion moment or work. Power generation was significantly greater on the dominant compared to the non-dominant extremity during the more challenging aggregate surface and ramp conditions. CONCLUSIONS: Propulsion effort varies with demands imposed by different ground conditions. Quantification of wheelchair propulsion demands provides rehabilitations specialists with objective information to guide treatment of patients adapting to manual wheelchair use.