Biomedical subjects

Joseph B Myers

Publications and source records attributed to Joseph B Myers.

18 recordsLinked to original sources

PubMed2006

Sensorimotor contribution to shoulder stability: effect of injury and rehabilitation.

Shoulder joint stability is the humeral head remaining or promptly returning to proper alignment within the glenoid fossa. This is mediated by both mechanical and dynamic restraint mechanisms. Coordination of these restraint systems is required for shoulder joint stability. The sensorimotor system is defined as all of the sensory, motor, and central integration and processing components involved in maintaining joint stability. The sensorimotor system is comprised of several components including proprioception, joint position sense, kinesthesia, sensation of force, and neuromuscular control. With joint injury, not only are the mechanical restraints disrupted (joint capsule, glenoid labrum, etc.) but also, the sensorimotor system is affected. Restoration of the sensorimotor system has been shown to occur through both surgical and conservative intervention and rehabilitation. Surgery has been shown to restore both mechanical restraints and the sensorimotor system. Specific rehabilitation techniques have also been effective at improving the sensorimotor system in healthy and pathological patients.

Humans↗

PubMed2006

Scapular dysfunction in throwers with pathologic internal impingement.

STUDY DESIGN: Case control group study. OBJECTIVES: To compare scapular position and orientation between baseball players with and without pathologic internal impingement. BACKGROUND: Scapular dysfunction has been implicated as a contributor to throwing-related pathologic internal impingement of the shoulder due to its role in increasing the contact between the greater tuberosity and posterior-superior glenoid, thereby impinging the posterior rotator cuff tendon(s) and labrum. However, to date, no definitive data demonstrate this scapular dysfunction in throwing athletes. The purpose of this study was to assess, in a controlled laboratory environment, whether scapular position and orientation would be different in throwing athletes diagnosed with pathologic internal impingement than in a control group of throwing athletes. METHODS AND MEASURES: Eleven throwing athletes diagnosed with pathologic internal impingement, using both clinical examination and a magnetic resonance arthrogram, were demographically matched with a control group of 11 throwers with no history of upper extremity injury. An electromagnetic tracking device was used to measure scapular internal/external rotation, anterior/posterior tilt, upward/downward rotation, sternoclavicular protraction/retraction, and elevation/depression during humeral elevation within the scapular plane. Comparisons were made between groups with analysis of variance models (P<.05). RESULTS: The individuals in the pathologic internal impingement group demonstrated statistically significant increased sternoclavicular elevation when elevating their humerus from 30 degrees to 120 degrees (P = .002) and from 60 degrees to 120 degrees (P = .003), compared to the control group. Furthermore, these patients also had increased posterior scapular tilt position (P = .016). No statistically significant differences were present in any other scapular variables measured. CONCLUSIONS: Based on the results of this study, throwing athletes diagnosed with pathologic internal impingement present with statistically significant increases in sternoclavicular elevation and scapular posterior tilt position during humeral elevation in the scapular plane.

Adult↗

PubMed2005

Glenohumeral range of motion deficits and posterior shoulder tightness in throwers with pathologic internal impingement.

BACKGROUND: Alterations in glenohumeral range of motion, including increased posterior shoulder tightness and glenohumeral internal rotation deficit that exceeds the accompanying external rotation gain, are suggested contributors to throwing-related shoulder injuries such as pathologic internal impingement. Yet these contributors have not been identified in throwers with internal impingement. HYPOTHESIS: Throwers with pathologic internal impingement will exhibit significantly increased posterior shoulder tightness and glenohumeral internal rotation deficit without significantly increased external rotation gain. STUDY DESIGN: Case control study; Level of evidence, 3. METHODS: Eleven throwing athletes with pathologic internal impingement diagnosed using both clinical examination and a magnetic resonance arthrogram were demographically matched with 11 control throwers who had no history of upper extremity injury. Passive glenohumeral internal and external rotation were measured bilaterally with standard goniometry at 90 degrees of humeral abduction and elbow flexion. Bilateral differences in glenohumeral range of motion were used to calculate glenohumeral internal rotation deficit and external rotation gain. Posterior shoulder tightness was quantified as the bilateral difference in passive shoulder horizontal adduction with the scapula retracted and the shoulder at 90 degrees of elevation. Comparisons were made between groups with dependent t tests (P < .05). RESULTS: The throwing athletes with internal impingement demonstrated significantly greater glenohumeral internal rotation deficit (P = .03) and posterior shoulder tightness (P = .03) compared with the control subjects. No significant differences were observed in external rotation gain between groups (P = .16). CLINICAL RELEVANCE: These findings could indicate that a tightening of the posterior elements of the shoulder (capsule, rotator cuff) may contribute to impingement. The results suggest that management should include stretching to restore flexibility to the posterior shoulder.

Adult↗

PubMed2005

The effect of direction and reaction on the neuromuscular and biomechanical characteristics of the knee during tasks that simulate the noncontact anterior cruciate ligament injury mechanism.

BACKGROUND: Jumping and landing tasks that have a change in direction have been implicated as a mechanism of noncontact anterior cruciate ligament injury. Yet, to date, neuromuscular and biomechanical research has focused primarily on straight landing tasks during planned jumps. HYPOTHESIS: Lateral and reactive jumps increase the neuromuscular and biomechanical demands placed on the anterior cruciate ligament, and women perform these tasks differently from men. STUDY DESIGN: Controlled laboratory study. METHODS: A total of 18 male and 17 female healthy high school basketball players underwent an analysis of the knee during planned and reactive 2-legged stop-jump tasks in 3 different directions that included novel methodology to incorporate a reactive component. Ground-reaction forces, joint kinematics, joint kinetics, and electromyographic activity were assessed during the tasks. RESULTS: Jump direction and task (planned or reactive) significantly affected joint angles, ground-reaction forces, knee joint moments, and proximal anterior tibia shear forces; female players demonstrated different kinematic, kinetic, and electromyographic characteristics during these tasks. CONCLUSION AND CLINICAL RELEVANCE: Jump direction significantly influenced knee biomechanics, suggesting that lateral jumps are the most dangerous of the stop-jumps. Reactive jumps were also significantly different, suggesting differences between planned laboratory experiments and actual athletic competition. The results of this study indicate that directional and reactive jumps should be included in research methodology and injury-prevention programs.

Adolescent↗

PubMed2005

Scapular position and orientation in throwing athletes.

BACKGROUND: Despite the recognized importance of proper 3-dimensional motion of the scapula in throwers, minimal research has quantified scapular position and orientation in throwing athletes. HYPOTHESIS: Throwing athletes exhibit scapular position and orientation differences when compared to nonthrowing control subjects. STUDY DESIGN: Descriptive laboratory study. METHODS: Scapular position and orientation during scapular plane humeral elevation were assessed with electromagnetic tracking in a group of 21 throwing athletes and 21 control subjects. Scapular upward/downward rotation, internal/external rotation, anterior/posterior tipping, elevation/depression, and protraction/retraction were assessed. RESULTS: The throwing athletes demonstrated significantly increased upward rotation, internal rotation, and retraction of the scapula during humeral elevation. No differences in anterior/posterior tipping and elevation/depression were present. CONCLUSIONS: The results indicate that throwing athletes have scapular position and orientation differences compared to non-throwing athletes. This suggests that throwers develop chronic adaptation for more efficient performance of the throwing motion. CLINICAL RELEVANCE: Clinicians evaluate scapular position, orientation, and movement in throwing athletes as part of the evaluation of shoulder injuries associated with the throwing motion. The current study provides clinicians with an understanding of the types of adaptations that may be observed in normal, healthy throwing athletes.

Adaptation, Physiological↗

PubMed2005

On-the-Field Resistance-Tubing Exercises for Throwers: An Electromyographic Analysis.

Context: Athletes who throw commonly use rubber-tubing resistance exercises in the field setting to assist with warm-up before throwing. Yet no researchers have described which muscles are being activated or which exercises are most effective during rubber-tubing exercises used by throwers for warm-up.Objective: To describe the effectiveness of 12 rubber-tubing resistance exercises commonly used by throwers in activating the shoulder muscles important for throwing.Design: Descriptive research design.Setting: An applied biomechanics research laboratory.Patients or Other Participants: Fifteen physically active male subjects with no history of shoulder injury.Main Outcome Measure(s): Subjects randomly performed 12 rubber-tubing resistance exercises while we assessed muscle activation of the subscapularis, supraspinatus, teres minor, and rhomboid major by indwelling electromyography. Activation of the sternal portion of the pectoralis major, anterior deltoid, middle deltoid, latissimus dorsi, serratus anterior, biceps brachii, triceps brachii, lower trapezius, and infraspinatus muscles was assessed by surface electromyography.Results: Performance of 7 exercises (external rotation at 90 degrees of abduction, throwing deceleration, humeral flexion, humeral extension, low scapular rows, throwing acceleration, and scapular punch) resulted in the highest level of muscle activation of all muscles tested.Conclusions: These 7 exercises exhibited moderate activation (>20% maximal voluntary isometric contraction) in each muscle of the rotator cuff, the primary humeral movers, and the scapular stabilizer muscles. The results suggest that these exercises are most effective in activating the muscles important to the throwing motion and may be beneficial for throwers during their prethrowing warm-up routine.

Journal Article↗

PubMed2005

Maxillofacial Fractures and Dental Trauma in a High School Soccer Goalkeeper: A Case Report.

Objective: To present the case of a 17-year-old male soccer goalkeeper who sustained maxillofacial fractures and dental trauma after being struck in the face by an opponent's knee.Background: Because of the nature of the sport and a lack of protective headgear, soccer players are at risk for sustaining maxillofacial trauma. Facial injuries can complicate the routine management of on-field medical emergencies often encountered by certified athletic trainers. The appropriate management of maxillofacial trauma on the playing field may help to reduce both the immediate and long-term morbidity and mortality associated with these injuries.Differential Diagnosis: Lacerated superior labial artery, lacerated upper lip, dental fractures, maxillofacial fractures, orbital blowout fracture, closed head injury, cervical spine injury, cerebrovascular accident.Treatment: The athlete received immediate on-field medical care and was subsequently transported to the hospital, where diagnostic testing was performed and further treatment was provided. Hospital inpatient management included dental and plastic surgery. After discharge from the hospital, the athlete underwent several additional dental procedures, including gingival surgery and nonsurgical endodontic treatments. The fractures were followed closely to assure that adequate healing had occurred. The athlete did not return to soccer.Uniqueness: Certified athletic trainers need to be prepared for on-field medical emergencies. Bleeding associated with maxillofacial trauma can complicate basic medical interventions such as airway maintenance. Inappropriate on-field management may result in unnecessary morbidity and mortality for the injured athlete. Therefore, immediate recognition of the severity of the injury is needed in order to institute appropriate airway-management strategies.Conclusions: It is sometimes necessary to consider nonstandard methods of airway management in order to first address heavy bleeding that may be associated with facial trauma. Achieving hemostasis is essential in order to prevent potentially life-threatening complications related to hemorrhage, such as airway obstruction and hypovolemic shock.

Journal Article↗

PubMed2004

Reflexive muscle activation alterations in shoulders with anterior glenohumeral instability.

BACKGROUND: Patients with glenohumeral instability have proprioceptive deficits that are suggested to contribute to muscle activation alterations. HYPOTHESIS: Muscle activation alterations will be present in shoulders with anterior glenohumeral instability. STUDY DESIGN: Posttest-only control group design. METHODS: Eleven patients diagnosed with anterior glenohumeral instability were matched with 11 control subjects. Each subject received an external humeral rotation apprehension perturbation while reflexive muscle activation characteristics were measured with indwelling electromyography and surface electromyography. RESULTS: Patients with instability demonstrated suppressed pectoralis major and biceps brachii mean activation; increased peak activation of the subscapularis, supraspinatus, and infraspinatus; and a significantly slower biceps brachii reflex latency. Supraspinatus-subscapularis coactivation was significantly suppressed in the patients with instability as well. CONCLUSIONS AND CLINICAL RELEVANCE: In addition to the capsuloligamentous deficiency and proprioceptive deficits present in anterior glenohumeral instability, muscle activation alterations are also present. The suppressed rotator cuff coactivation, slower biceps brachii activation, and decreased pectoralis major and biceps brachii mean activation may contribute to the recurrent instability episodes seen in this patient group. Clinicians can implement therapeutic exercises that address the suppressed muscles in patients opting for conservative management or rehabilitation before and after capsulorraphy procedures.

Adult↗

PubMed2004

Effect of lateral ankle ligament anesthesia on single-leg stance stability.

PURPOSE: This study was designed to determine, in isolation, the contribution of lateral ankle ligament mechanoreceptors to postural stability during single leg static (eyes open, eyes closed) and landing tasks. METHODS: Fourteen healthy subjects (nine males, five females) underwent two different treatment conditions (control, anesthesia) in a counterbalanced order (48-h interval). During the anesthetic treatment, lidocaine was injected into the anterior talofibular and calcaneofibular ligament (1.5 cc each) regions. Postural stability was measured using forceplate and kinematic variables. The average of each variable across multiple trials under each treatment for the three tasks was analyzed statistically. RESULTS: Results of all statistical analyses failed to demonstrate significant alterations (P > 0.05) in postural control attributable to the treatment condition. CONCLUSION: These results suggest that lateral ankle ligament mechanoreceptors either do not make a significant contribution to single leg stance stability, do not have a unique, irreplaceable role, or have a role that is too subtle to be detected given the measurement techniques used. Thus, the idea that single leg stability becomes altered after ankle joint injury because of proprioceptive disruption was not supported. This would suggest that reported postural control alterations in persons after repetitive ankle injury more likely occur as a result of alterations in mechanical stability, motor components, and/or central motor programming.

Adult↗

PubMed2003

Kinematic analysis of the hip and trunk during bilateral stance on firm, foam, and multiaxial support surfaces.

OBJECTIVE: To differentiate hip and trunk motion during double-leg stance. DESIGN: Trunk and hip angular position variances were measured on different support surfaces with and without vision. BACKGROUND: Postural control results from motion about the hips and trunk during bilateral stance. While the hip joint has been studied extensively, information concerning relative amounts of hip and trunk motions during postural control is limited. METHODS: Trunk flexion/extension, trunk lateral flexion, right and left hip flexion/extension and abduction/adduction angular position variances were assessed in 14 normal subjects using an electromagnetic tracking system during bilateral stance on firm, foam, and multiaxial support surfaces with and without vision. RESULTS: Significantly greater amounts of motion occurred at all joints for the multiaxial-eyes closed condition compared to all other surface-vision conditions. No significant differences were found between any other surface-vision conditions. Within the multiaxial-eyes closed condition, right and left hip flexion/extension and abduction/adduction magnitudes were significantly greater than those of trunk flexion and lateral flexion, and left hip flexion/extension motion was significantly greater than that of the right hip. CONCLUSIONS: Postural control mechanisms involve similar amounts of motion at the hips and trunk, except for conditions under which a rigid base of support becomes unstable and vision is eliminated. RELEVANCE: These results suggest that the trunk and hips should be considered separately during kinematic analysis of postural control. This information may be useful in providing a more sensitive assessment of postural control to identify balance-related pathologies associated with stroke, concussion, and somatosensory deficits.

Abdomen↗

PubMed2003

Comparison of the ankle, knee, hip, and trunk corrective action shown during single-leg stance on firm, foam, and multiaxial surfaces.

OBJECTIVE: To compare the quantity of ankle, knee, hip, and trunk corrective actions shown during single-leg stance. DESIGN: Counter-balanced crossover design. Single-leg stance under the conditions of eyes open on firm, foam, and multiaxial surfaces and eyes closed on a firm surface were recorded for 12 seconds in 18 participants. SETTING: A university neuromuscular research laboratory. PARTICIPANTS: Eighteen healthy and recreationally active college students. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: Average angular displacement magnitude between successive sampling instances for the ankle, knee, hip, and trunk. RESULTS: A significant condition by joint interaction was revealed. Post hoc comparisons revealed that the ankle dominated as the source of corrective action across each of the testing conditions. As the challenge became greater because of foam surface or eyes closed, more corrective action occurred at proximal joints (hip and/or knee). CONCLUSIONS: The ankle is of primary importance during single-leg stance on firm, foam, and multiaxial surfaces, with proximal joints having an increased role under more challenging conditions. These results provide a scientific basis for clinicians' and researchers' decisions about support surface and visual condition during single-leg postural control testing and training.

Adolescent↗

PubMed2003

Shoulder muscle reflex latencies under various levels of muscle contraction.

Previous research in relaxed muscles shows that muscle reflex latencies are too slow to protect the shoulder. However, during athletic activity when injury occurs, some level of shoulder muscle contraction typically exists. The purpose of the current study was to assess shoulder muscle reflex latencies under various levels of muscle contraction. Seventeen healthy subjects participated. A perturbation consisting of an external rotation collision force to the anterior forearm in a position of apprehension under various levels of muscle contraction (0%, 20%, and 50% of a maximum voluntary muscle contraction) was applied. Muscle reflex latencies were measured as the time from perturbation application to onset of muscle activity. Electromyography measured activity onset of the rotator cuff muscles and the primary humeral movers. During 0%, the latissimus dorsi muscle reflex latency was significantly slower than most other muscles. No difference existed between muscles in the 20% and 50% conditions. For the rotator cuff muscles, the reflex latencies significantly quickened for 20% and 50% compared with the relaxed state (0%). Overall, introducing muscle contraction significantly quickened muscle reflex latencies. These results provide clinicians with a better understanding of the role that these reflexes play in joint stability in a position of injury vulnerability like a position of apprehension.

Adult↗

PubMed2002

Shoulder proprioception and function following thermal capsulorraphy.

PURPOSE: Because monopolar radiofrequency energy has a denaturing effect on the glenohumeral joint capsule during thermal capsulorraphy, we hypothesized that thermal treatment would have a deleterious effect on the mechanoreceptors present within the capsule, thereby affecting proprioception and function. The purpose of this study was to evaluate proprioception and function following thermal capsulorraphy. TYPE OF STUDY: Case series. METHODS: Twenty subjects (13 male, 7 female) diagnosed with unilateral anterior, anteroinferior, or multidirectional glenohumeral instability with no significant concomitant pathologies, were treated with monopolar radiofrequency thermal capsulorraphy by one surgeon. Capsular redundancy was the primary diagnosis in all subjects. Subjects were bilaterally tested retrospectively 6 to 24 months (11.90 +/- 5.65 months) following surgery. Each subject's ability to actively reproduce joint positions (ARJP) and reproduce paths of motion (PMR) was measured with an electromagnetic motion analysis system. Both passive reproduction of joint positions (PRJP) and threshold to detect passive motion (TTDPM) were measured using a proprioception testing device. Function was quantified with the Shoulder Rating Questionnaire (SRQ). Proprioception data were analyzed with separate repeated measures ANOVA (P <.05). RESULTS: Statistical analysis revealed a significant ARJP difference between the involved and uninvolved limb (P =.005) indicating that reproduction error was less with the involved limb compared to the uninvolved limb. No significant interactions were present for TTDPM, PRJP, or PMR. The SRQ indicates that the subjects returned to near normal function (91.86/100 +/- 5.38 points) at the time of testing. CONCLUSIONS: The results from this study do not support our hypothesis of proprioception and functional deficits following thermal treatment. Normalized proprioception following thermal capsulorraphy may have resulted from the healing effects of thermal treated ligament, as reported in the literature, as well as facilitation of other mechanoreceptors present in adjacent tissue about the shoulder joint during rehabilitation. The results of this study indicate that no appreciative deleterious effects exist with proprioception and function following treatment of shoulder instability with thermal capsulorraphy.

Adult↗

PubMed2002

Sensorimotor deficits contributing to glenohumeral instability.

The conventional perspective has been that capsuloligamentous structures act as a mechanical restraint to humeral translation at the shoulder. Although this is true, the capsuloligamentous structures also have a sensorimotor influence on the musculoskeletal system, providing stability at the shoulder. The purpose of the current study was to discuss the sensorimotor role that the capsuloligamentous structures play in providing stability, how these mechanisms are disrupted with glenohumeral instability, and how surgical intervention restores such mechanisms. Proprioceptive information transmitted from the mechanoreceptors embedded within the capsuloligamentous structures influence the coordinated motor patterns, reflex activity, and joint stiffness to provide enhanced joint stability. The capsuloligamentous injury that occurs with shoulder instability not only affects mechanical restraint, but also alters this proprioceptive input to the central nervous system. As a result of these deficits in proprioception, alterations in reflex activity and motor programs as evident by muscle firing pattern alterations manifest. Although the main goal of surgical intervention is to restore the mechanical restraint that is lost with joint dislocation or subluxation, surgical intervention whether through open, arthroscopic, or thermal techniques seem to restore the proprioceptive deficits that exist after joint injury.

Humans↗

PubMed2002

Gender differences in strength and lower extremity kinematics during landing.

This study evaluated kinematic, vertical ground reaction forces, and strength variables in healthy collegiate female basketball, volleyball, and soccer players compared with matched male subjects. Thirty athletes did single-leg landing and forward hop tasks. An electromagnetic tracking device synchronized with a force plate provided kinematic data and vertical ground reaction force data, respectively. Maximum angular displacement and time to maximum angular displacement kinematic variables were calculated for hip flexion, abduction, rotation, knee flexion, and lower leg rotation. Vertical ground reaction force data normalized to body mass provided impulse, maximum force, time to maximum force, and stabilization time variables. An isokinetic device measured quadriceps and hamstring peak torque to body mass at 60 degrees /second. With both tasks, females had significantly less knee flexion and lower leg internal rotation maximum angular displacement, and less knee flexion time to maximum angular displacement than males. For the single-leg land, females had significantly more hip internal rotation maximum angular displacement, and less lower leg internal rotation time to maximum angular displacement than males. For the forward hop, females had significantly more hip rotation time to maximum angular displacement than males. Females also had significantly less peak torque to body mass for the quadriceps and hamstrings than males. Weaker thigh musculature may be related to the abrupt stiffening of the knee and lower leg on landing in females.

Adult↗

PubMed2002

Survey of the injury rate for children in community sports.

OBJECTIVE: To determine the baseline injury rate for children ages 7 to 13 participating in community organized baseball, softball, soccer, and football. METHODS: In this observational cohort study, 1659 children were observed during 2 seasons of sports participation in an urban area. Data were collected by coaches using an injury survey tool designed for the study. A reportable injury was defined as one requiring on-field evaluation by coaching staff, or causing a player to stop participation for any period of time, or requiring first aid during an event. Logistic regression analyses were done within and across sports for injury rates, game versus practice injury frequencies, and gender differences where appropriate. RESULTS: The injury rates, calculated per 100 athlete exposures during total events (games plus practices), were: baseball, 1.7; softball, 1.0; soccer, 2.1; and football, 1.5. The injury rates for baseball and football were not significantly different. Across sports, contusions were the most frequent type of injury. Contact with equipment was the most frequent method of injury, except in football where contact with another player was the most frequent method. In baseball, 3% of all injuries reported were considered serious (fracture, dislocation, concussion); in soccer, 1% were considered serious; and in football, 14% were considered serious. The frequency of injury per team per season (FITS), an estimation of injury risk, was 3 for baseball and soccer, 2 for softball, and 14 for football for total events. For all sports, there were more game than practice injuries; this difference was significant except for softball. There were no significant gender differences in soccer for injury rates during total events. CONCLUSIONS: Given the classification of football as a collision sport, the high number of exposures per player, the FITS score, and the percentage of injuries considered serious, youth football should be a priority for injury studies. Health professionals should establish uniform medical coverage policies for football even at this age level. RECOMMENDATIONS FOR MODIFICATIONS: Injury surveillance for youth sports is gaining momentum as an important step toward formulating injury prevention methods. However, establishing patterns of injuries, taking preventive measures, and evaluating equipment and coaching modifications may take years. In addition to the objective findings of this study, our direct observations of community sports through 2 seasons showed areas where immediate modifications could reduce injury risk. The first recommendation is that youth sports leagues provide and require first aid training for coaches. Training could be done by sports medicine professionals and include recognition and immediate response to head, neck, and spine injuries, as well as heat-related illnesses. The second recommendation is that youth sports leagues have clear, enforceable return to play guidelines for concussions, neck and back injuries, fractures, and dislocations. The third recommendation is that baseball and softball leagues consider the injury prevention potential of face guards on batting helmets.

Athletic Injuries↗

PubMed2002

Sensorimotor system measurement techniques.

OBJECTIVE: To provide an overview of currently available sensorimotor assessment techniques. DATA SOURCES: We drew information from an extensive review of the scientific literature conducted in the areas of proprioception, neuromuscular control, and motor control measurement. Literature searches were conducted using MEDLINE for the years 1965 to 1999 with the key words proprioception, somatosensory evoked potentials, nerve conduction testing, electromyography, muscle dynamometry, isometric, isokinetic, kinetic, kinematic, posture, equilibrium, balance, stiffness, neuromuscular, sensorimotor, and measurement. Additional sources were collected using the reference lists of identified articles. DATA SYNTHESIS: Sensorimotor measurement techniques are discussed with reference to the underlying physiologic mechanisms, influential factors and locations of the variable within the system, clinical research questions, limitations of the measurement technique, and directions for future research. CONCLUSIONS/RECOMMENDATIONS: The complex interactions and relationships among the individual components of the sensorimotor system make measuring and analyzing specific characteristics and functions difficult. Additionally, the specific assessment techniques used to measure a variable can influence attained results. Optimizing the application of sensorimotor research to clinical settings can, therefore, be best accomplished through the use of common nomenclature to describe underlying physiologic mechanisms and specific measurement techniques.

Journal Article↗

PubMedDate not supplied

Effect of peripheral afferent alteration of the lateral ankle ligaments on dynamic stability.

BACKGROUND: The sensorimotor influence of the lateral ankle ligaments in muscle activation is unclear. HYPOTHESIS: The lateral ankle ligaments have significant sensorimotor influence on muscle activation. STUDY DESIGN: Controlled laboratory study. METHODS: Muscle-firing characteristics in response to a high-speed inversion perturbation and during gait were assessed in 13 normal subjects. Solutions (1.5% lidocaine or a placebo of saline) were injected bilaterally into the anterior talofibular and calcaneofibular ligaments (1.5 ml per ligament) to alter peripheral afferent influence. Subjects were again tested with the same protocol. RESULTS: The protective response of the anterior tibialis and peroneal muscles during inversion perturbation and mean muscle activation amplitude decreased during running after both injections. After injection, no significant differences were seen for muscle reflex latencies, maximum amplitude, time to maximum amplitude during inversion perturbation, or mean amplitude during walking. CONCLUSION: The lateral ankle ligaments have a sensorimotor influence on muscle activation. CLINICAL RELEVANCE: Induced edema from the injected solutions may have altered the sensorimotor influence of the lateral ankle ligaments, thereby inhibiting the dynamic ankle stabilizers. This finding suggests that dynamic stability may be compromised because of swelling after joint injury.

Adult↗