A comparison of kinematic demands placed on the knee and hip during two ACL return-to-sport screening maneuvers and an agility test.

OBJECTIVES: This study's purpose was to compare the kinematic demands placed on the knee and the hip during various biomechanical tests. DESIGN: Retrospective cross-sectional design. SETTING: A university research laboratory. PARTICIPANTS: The study sample consisted of 70 NCAA Division I female athletes. MAIN OUTCOME MEASURES: During the performance of three test maneuvers, a drop vertical jump (DVJ), single leg cross over hop (COH) and modified T-test (AT), the hip and knee joint angles at maximum knee valgus were obtained from marker displacement data collected using a 20-camera motion analysis system. A linear mixed model was used to compare the effect of test on joint angle. RESULTS: A significant difference (p < 0.001) in the frontal and sagittal plane position of the knee and hip was noted between the DVJ, COH, and AT tests at maximum knee valgus. CONCLUSIONS: The DVJ, COH, and AT maneuvers do not appear to place the same kinematic stress on the knee, supporting the need for the development of return to sport tests that mimic on field demands.

Walking is regulated by environmental temperature.

The mechanisms that regulate human walking are not fully understood, although there has been substantial research. In our study, we hypothesized that, although walking can be volitionally modified, it is also involuntary and controlled by evolutionary factors, such as the relationship between temperature and movement speed in poikilotherms. This study aimed to determine the effects of environmental temperature on speed, step length, and cadence during unrestrained walking over long periods. Customers of a private insurance company were asked to use a background smartphone GPS application that measured walking parameters. Participants were 1065 app users (298 men and 767 women) aged 14-86 years. Observed walking speed and cadence were higher in winter (average maximum temperature: 10.2 °C) than in summer (average maximum temperature: 29.8 °C) (p < 0.001). The walking parameters were closely related to environmental temperature, with cadence most strongly correlated with daily maximum temperature (r = - 0.812, p < 0.001) and indicating a curvilinear relationship. A decrease in environmental temperature was found to increase cadence when the temperature was below 30 °C. The findings suggest that walking may be regulated by environmental temperature and potentially by the autonomic nervous system's response to environmental temperature.

The Missing Link: Defining the Functional Parameters of Pelvic and Acetabular Alignment.

BACKGROUND: This study aimed to define the three-dimensional functional alignment of the pelvis, proximal femur, and acetabulum during postural and physical activities. METHODS: Thirty volunteers aged 40 years or greater were recruited. Reflective markers placed on bony prominences on the pelvis and lower extremities were tracked using a 12-camera motion analysis system. Measurements were obtained for various postures (ie, supine, standing, and sitting) and activities (ie, walking and ascending/descending stairs). RESULTS: Significant pelvic motion occurred only in the sagittal plane. The mean posterior inclinations of the pelvis were 15°, 18°, and 51° in the supine, standing, and sitting positions, respectively. These corresponded to acetabular anteversion/inclination angles of 26°/44°, 28°/45°, and 55°/55°, respectively. For activities, the mean posterior inclinations of the pelvis were 19°, 19°, and 20° during walking and ascending and descending stairs, respectively. These corresponded to acetabular anteversion/inclination angles of 29°/45°, 29°/45°, and 30°/46°, respectively. DISCUSSION: The functional parameters for pelvic and acetabular alignment were defined. Further research is needed to understand the extent to which these normal parameters are altered in the setting of hip and/or spinal degenerative disease to guide acetabular implant placement.

Osteoarthritis, Osteophytes, and Enthesophytes Affect Biomechanical Function in Adults With X-linked Hypophosphatemia.

CONTEXT: X-Linked hypophosphatemia (XLH) is a lifelong metabolic disease with musculoskeletal comorbidities that dominate the adult clinical presentation. OBJECTIVE: The adult XLH disorder has yet to be quantified on the basis of the physical and functional limitations that can affect activities of daily living. Our goal was to report the impact of the musculoskeletal manifestations on physical function. DESIGN AND SETTING: Musculoskeletal function was evaluated by validated questionnaires and in an interdisciplinary clinical space where participants underwent full-body radiologic imaging, goniometric range of motion (ROM) measurements, general performance tests, and kinematic gait analysis. PATIENTS: Nine adults younger than 60 years with a diagnosis of XLH and self-reported musculoskeletal disability, but able to independently ambulate, were selected to participate. Passive ROM and gait analysis were also performed on age-approximated controls to account for differences between individual laboratory instrumentation. RESULTS: Enthesophytes, degenerative arthritis, and osteophytes were found to be consistently bilateral and diffusely present at the spine and synovial joints across participants, with predominance at weight-bearing joints. Passive ROM in adults with XLH was decreased at the cervical spine, hip, knee, and ankle compared to controls. Gait analysis relative to controls revealed increased step width, markedly increased lateral trunk sway, and physical restriction at the hip, knees, and ankle joints that translated into limitations through the gait cycle. CONCLUSIONS: The functional impact of XLH musculoskeletal comorbidities supports the necessity for creating an interprofessional health-care team with the goal of establishing a longitudinal plan of care that considers the manifestations of XLH across the lifespan.

Trunk Muscle Endurance, Flexibility, Stride Foot Balance, and Contralateral Trunk Lean in Collegiate Baseball Pitchers.

Myrick, KM, Pallone, AS, Feinn, RS, Ford, KM, and Garbalosa, JC. Trunk muscle endurance, flexibility, stride foot balance, and contralateral trunk lean in collegiate baseball pitchers. J Strength Cond Res 33(10): 2641-2647, 2019-The incidence of shoulder and elbow injuries in baseball is increasing. The trunk is crucial to transmission of energy from lower limbs, achieving the largest angular momentum and torque during pitching, and controlling acceleration of the arm. Excessive contralateral trunk lean has been correlated with increased ball velocity and forces on the elbow. Underlying biomechanical causes contributing toward excessive lean have not been well described. Previous studies outlined the importance of trunk muscle strength and endurance. Understanding contributing factors associated with contralateral lean and pitch velocity may be helpful in pitching performance, informing strength and conditioning protocols, and preventing injuries. The aim of this study was to examine the correlation between trunk muscle endurance and flexibility, and stride foot balance with contralateral lean during pitching. Level of significance was set at p < 0.05. Pitching motion analysis and functional assessments were obtained. Three-dimensional motion analysis was used. Average degree of contralateral lean was 2.33° (SD = 3.66). No statistically significant relationships were identified between trunk muscle endurance, flexibility, and stride foot balance with contralateral lean; moderate negative association between contralateral lean and pitch speed (B = -0.631, p = 0.175) was identified along with negative association of ipsilateral maximum trunk rotation (r = -0.108, p = 0.208) and ipsilateral side plank (r = -0.095, p = 0.194) with contralateral lean. Contralateral lean does not appear influenced by trunk muscle endurance, flexibility, or stride foot balance, and does not increase pitch velocity in high velocity pitchers. Future study is warranted to determine why contralateral lean exists at lower pitch velocities, and not at higher velocities.

Effects of season long participation on ACL volume in female intercollegiate soccer athletes.

BACKGROUND: The aim of this study was to characterize the volumetric changes of the anterior cruciate ligament over the course of a competitive soccer season in female athletes. METHODS: Seventeen Division-I collegiate soccer players were recruited. Two data collection sessions were conducted. The first data collection occurred prior to the start of the soccer season. Each subject completed a brief questionnaire, had height and weight measured, underwent a clinical assessment of their anterior cruciate ligaments and an eight sequence magnetic resonance imagery of their knees. Contours of the anterior cruciate ligaments were outlined in sagittal T-2 weighted MR images and volumes were calculated using Medical Image Processing, Analysis, and Visualization software. Presence or absence of edema within the ligament was determined in pre and post season scans. All subjects were followed during the season to determine if a lower extremity injury had been sustained. RESULTS: Mean ligament volume significantly increased from preseason to postseason (p=.006). There was a 10% increase in the percentage of knees with edema pre to post season. CONCLUSIONS: The physical demand of a competitive soccer season in female collegiate athletes appears to cause an increase in volume of the anterior cruciate ligament. The increase in volume may be related to the accumulation of microscopic tears over the course of the season which induce inflammation and edema. The volumetric changes in the ligament may have significant clinical implications, however further studies must be done to determine the relationship between anterior cruciate ligament volume and risk of injury.

Quantification characteristics of digital spiral analysis for understanding the relationship among tremor and clinical measures in persons with multiple sclerosis.

BACKGROUND: Multiple sclerosis (MS) is a degenerative neurological condition causing demyelination and neuronal loss. Tremor, a symptom of MS, is prevalent in 45.0-46.8% NARCOMS registrants. Although several tools to measure tremor exist, few outcomes are quantitative or regularly utilized clinically. NEW METHOD: Introduction of a novel adaptation of the digital spiral drawing to find a quick, sensitive, and clinically useful technique, to predict tremor in persons with MS (pwMS). Digital spiral measures included: Segment Rate (SEGRT), Standard Deviation (SD) of Radial Velocity (VSD-R), SD of Tangential Velocity (VSD-T), SD of Overall Velocity (VSD-O), Mean Drawing Velocity (MNV-O) and Mean Pen Pressure Acceleration (MNA-P). Digital spiral measures were compared with the manual Archimedes Spiral (AS) drawing and the following clinical measures: Finger-Nose Test (FNT), presence of visually observed intention tremor (VOT), Nine-Hole Peg Test (NHPT), and Box and Block Test (BBT). RESULTS: All clinical measures utilized demonstrated significant relationships with all digital variables, except VSD-R. The forward-stepwise regression revealed BBT accounted for the most variance, followed by SEGRT. Comparison with Existing Methods: SEGRT is more sensitive in detecting VOT and better for quantifying tremor than AS. BBT and SEGRT are optimal predictive measures for tremor. CONCLUSIONS: SEGRT has stronger sensitivity and negative predictive value than AS in detecting VOT. All clinical measures (NHPT, FNT, BBT, and AS) were significantly associated with the digital variables (SEGRT, VSD-T, VSD-O, MNV-O, and MNA-P) except for VSD-R. After controlling for Patient Determined Disease Steps (PDDS), BBT and SEGRT are the best predictive measures for tremor.

The effect of orthotics on intersegmental foot kinematics and the EMG activity of select lower leg muscles.

BACKGROUND: Persons with exertional related leg pain are managed using orthoses. This study aimed to determine the effectiveness of two orthoses in altering foot motion and muscle activity in symptomatic individuals. METHODS: 52 subjects with lower extremity pain complaints of a non-traumatic, mechanical origin received one of two orthoses. Foot kinematics and EMG activity were recorded while treadmill walking in 3 footwear conditions. The peak EMG activity of the sandal and sandal orthotic trials (normalized to peak barefoot values) and foot motion during 4 subphases of stance were obtained. Using a multivariate multilevel model via linear mixed models, the effect of orthoses within these phases on motion and EMG was determined. RESULTS: An effect of orthotic type was not present for any of the rearfoot or forefoot motions (p>.10). A significant effect of footwear and orthotic type on first ray motion (p<.05) during subphases 2 and 4 was seen. During subphase 4 an interaction effect between footwear condition and orthotic type on tibialis posterior EMG activity (p=.036) was present. CONCLUSION: Orthoses are unable to control rear or midfoot motion but appear to control first ray motion and during late stance, affect tibialis posterior muscle activity. Public trials registry number: NCRT02143947.

Lower limb kinematics of male and female soccer players during a self-selected cutting maneuver: Effects of prolonged activity.

BACKGROUND: Despite the recent emphasis on injury prevention, anterior cruciate ligament (ACL) injury rates remain high. This study aimed to ascertain the effects of prolonged activity on lower limb kinematics during a self-selected cutting maneuver. METHODS: Angular kinematics were recorded during an agility test performed until the completion time was greater than the mean plus one SD of baseline trials. Cut type was identified and the hip and knee angles at 33 ms post heel strike were determined. A linear mixed effects model assessed the effects of cut type, gender, and activity status on the hip and knee angles. RESULTS: Males performed sidestep cuts more frequently than females. Females increased the incidence of sidestep cuts after prolonged activity. At the hip, a gender-cut type interaction existed for the transverse (p=0.001) and sagittal (p=0.11) planes. Females showed more internal rotation during sidestep and more external rotation and less flexion during crossover cuts. For the frontal plane, a gender-activity status interaction (p = 0.032) was due to no change within females but greater hip adduction during prolonged activity within males. With prolonged activity, both genders displayed less hip (p=0.29) and knee (p=0.009) flexion and more knee (p=0.001) adduction. Females displayed less hip and knee flexion than men (p=0.001). CONCLUSIONS: Sidestep may be more risky than crossover cuts. Both genders place themselves in at-risk postures with prolonged activity due to less hip and knee flexion.

Sidestep and crossover lower limb kinematics during a prolonged sport-like agility test.

BACKGROUND: Non-contact anterior cruciate ligament (ACL) injuries in athletes occur more often towards the end of athletic competitions. However, the exact mechanisms of how prolonged activity increases the risk for ACL injuries are not clear. PURPOSE: To determine the effect of prolonged activity on the hip and knee kinematics observed during self-selected cutting maneuvers performed in a timed agility test. METHODS: Nineteen female Division I collegiate soccer players completed a self-selected cutting agility test until they were unable to meet a set performance time (one standard deviation of the average baseline trial). Using the 3D dimensional coordinate data the cut type was identified by the principle investigators. The 3D hip and knee angles at 32ms post heel strike were analyzed using a two-factor, linear mixed model to assess the effect of prolonged activity and cut type on the recorded mean hip and knee angles. RESULTS: Athletes performed either sidestep or crossover cuts. An effect of cut type and prolonged activity was seen at the hip and knee. During the prolonged activity trials, the knee was relatively more adducted and both the hip and knee were less flexed than during the baseline trials regardless of cut type. Regardless of activity status, during sidestep cuts, the hip was more internally rotated and abducted, and less flexed than during crossover cuts while the knee was more abducted and less flexed during the sidestep than crossover cuts. CONCLUSIONS: During a sport-like agility test, prolonged activity appears to predispose the athlete to position their knee in a more extended and abducted posture and their hip in a more extended posture. This position has been suggested to place stress on the ACL and potentially increase the risk for injury. Clinicians may want to consider the effects of prolonged activity on biomechanical risk factors for sustaining ACL injuries in the design of intervention strategies to prevent ACL injuries. LEVEL OF EVIDENCE: Level 4.

Validity of two alternative systems for measuring vertical jump height.

Vertical jump height is frequently used by coaches, health care professionals, and strength and conditioning professionals to objectively measure function. The purpose of this study is to determine the concurrent validity of the jump and reach method (Vertec) and the contact mat method (Just Jump) in assessing vertical jump height when compared with the criterion reference 3-camera motion analysis system. Thirty-nine college students, 25 females and 14 males between the ages of 18 and 25 (mean age 20.65 years), were instructed to perform the countermovement jump. Reflective markers were placed at the base of the individual's sacrum for the 3-camera motion analysis system to measure vertical jump height. The subject was then instructed to stand on the Just Jump mat beneath the Vertec and perform the jump. Measurements were recorded from each of the 3 systems simultaneously for each jump. The Pearson r statistic between the video and the jump and reach (Vertec) was 0.906. The Pearson r between the video and contact mat (Just Jump) was 0.967. Both correlations were significant at the 0.01 level. Analysis of variance showed a significant difference among the 3 means F(2,235) = 5.51, p < 0.05. The post hoc analysis showed a significant difference between the criterion reference (M = 0.4369 m) and the Vertec (M = 0.3937 m, p = 0.005) but not between the criterion reference and the Just Jump system (M = 0.4420 m, p = 0.972). The Just Jump method of measuring vertical jump height is a valid measure when compared with the 3-camera system. The Vertec was found to have a high correlation with the criterion reference, but the mean differed significantly. This study indicates that a higher degree of confidence is warranted when comparing Just Jump results with a 3-camera system study.

A retrospective study of patients with diabetes mellitus after partial foot amputation and hyperbaric oxygen treatment.

A retrospective chart review was conducted of 35 patients (40 feet) who received hyperbaric oxygen (HBO) therapy after partial foot amputation between 1990 and 2000. Preoperative transcutaneous partial pressure of oxygen (tcPO2) levels, the number of hyperbaric treatments, time to final outcome, use of revascularization procedures, and postsurgical outcome were extracted from the charts. Seventy percent (n = 28) had a successful outcome, defined as complete healing and absence of ulceration at the amputation site, and lack of further surgical procedures to heal the amputation site; whereas 30% (n = 12) had a failed outcome, defined as lack of healing or the presence of an ulcer at the site of amputation or the need for further surgery to heal the amputation site. The level of amputation, use of revascularization procedures, time to final outcome, and number of hyperbaric treatments were not significantly different (P > .05) between the 2 postsurgical outcome groups. The mean preoperative tcPO2 levels were greater (P < .01) in the successful (24 +/- mm Hg) than in the failed (11 +/- mm Hg) outcome groups. All patients with a tcPO2 level > 29 mm Hg had a successful outcome. Patients with a successful postsurgical outcome had a mean of 20 HBO treatments and took 44 days to final outcome, while those with a failed postsurgical outcome had 16 HBO treatments and took 216 days to final outcome.

The value of radiographic parameters in the surgical treatment of hallux rigidus.

The purpose of this study was to determine if metatarsal protrusion or the length of the first and second rays were associated with the incidence of hallux rigidus. For this retrospective study, anteroposterior radiographs from 51 patients diagnosed with hallux rigidus and 51 patients without evidence of hallux rigidus were selected for review as a control group. Radiographs were randomly assigned to one of two raters who determined the metatarsal protrusion distance, first metatarsal length, second metatarsal length, length of the proximal phalanx of the hallux, length of the proximal phalanx of the second toe, and overall hallux length. A statistical comparison of these radiographic measurements showed only first metatarsal length to significantly differ (P = .05) between the two groups (65.4 +/- 5.3 mm and 67.7 +/- 5.9 mm for the hallux rigidus and control groups, respectively). The findings of this study suggest the need to revisit the role that metatarsal protrusion distance and first metatarsal length play in the etiology of hallux rigidus. In addition the need to surgically correct a long first metatarsal should be further evaluated.

The efficacy of prophylactic intravenous antibiotics in elective foot and ankle surgery.

A retrospective chart review of 555 patients who received elective foot and ankle surgeries between 1995 and 2001 at 1 outpatient podiatric hospital clinic was performed to evaluate the efficacy of preoperative intravenous antibiotic use. Only those patients who were having elective foot or ankle surgery for the first time, were being followed up at the hospital's outpatient clinic, and had a nontraumatic cause for their surgery were included in this study. A wound was considered infected when purulent material from the wound sites was noted and an organism(s) was cultured. A wound complication was defined as a superficial dehiscence, edema, erythema, or stitch abscess. Three hundred six (55.1%) patients received a preoperative antibiotic and 249 (44.9%) patients did not. Of the 306 patients who received a preoperative antibiotic, 9 (1.6%) acquired a postoperative wound infection, whereas 8 (1.4%) of the 249 patients who did not receive preoperative antibiotics acquired a postoperative infection. A logistic regression model and chi square tests of association were used to determine if preoperative antibiotic use, age, gender, type of surgical procedure, operative time, tourniquet use, past medical history, and internal fixation were predictive of or associated with postoperative wound infection or complication. None of the study factors was predictive of postoperative wound infection or complication (P >.01). Preoperative antibiotic use was associated with surgical category and internal fixation use (P <.001) but not postoperative wound infection or complication (P >.01). The results suggest that prophylactic intravenous antibiotic use in routine elective foot and ankle surgery is not warranted.