Biomedical subjects

J Nyland

Publications and source records attributed to J Nyland.

At least 19 recordsLinked to original sources

PubMed2006

Shoulder and elbow function 2 years following long head triceps interposition flap transfer for massive rotator cuff tear reconstruction.

INTRODUCTION: Patient outcomes were determined at a minimum of 2 years following massive rotator cuff tear ( > or = 5 cm(2)) reconstruction using a triceps brachii long head interposition flap. A physiotherapist at an independent clinic performed all measurements. PATIENTS AND METHODS: Of 24 total eligible patients, 19 completed pre-operative and follow-up UCLA Shoulder Scores and ASES Function Scores. Of these 19 patients, 14 who did not have co-morbidities that negatively impacted their ability to perform intense exercise underwent a comprehensive clinical examination of involved and uninvolved side shoulder and elbow active range of motion and strength (both isometric instrumented manual muscle testing and concentric isokinetic measurements). RESULTS: At 2 years following surgery, pre-operative UCLA Shoulder Scores improved from 10.6 +/- 3 to 27.4 +/- 5 and pre-operative ASES Function Scores improved from 20.1 +/- 10 to 43.2 +/- 5. However, isometric involved side shoulder abductor torque was decreased by 28.2% with instrumented manual muscle testing, and concentric shoulder external rotator torque was decreased by 44.6% at 60 degrees/s and by 53.8% at 120 degrees/s with isokinetic testing. Isometric involved side elbow extensor torque was decreased by 39% with instrumented manual muscle testing, and concentric elbow extensor torque was decreased by 17.7% and 19.2% at 60 and 120 degrees/s, respectively, with isokinetic testing. Including three additional patients who were contacted via telephone, the majority of patients (21 of 22, 95.4%) were satisfied with their improved shoulder function and reduced pain. CONCLUSIONS: Despite reduced pain and improved shoulder function, residual involved side shoulder abductor; shoulder external rotator and elbow extensor strength deficits were evident at 2 years following surgery. This suggests the need for more focused rehabilitation, particularly for involved side elbow extensor strengthening to further improve patient function and minimize disability.

Aged↗

PubMed2004

Femoral anteversion influences vastus medialis and gluteus medius EMG amplitude: composite hip abductor EMG amplitude ratios during isometric combined hip abduction-external rotation.

This prospective study evaluated differences in vastus medialis (VM) and gluteus medius (GM) EMG amplitude:composite hip abductor (gluteus maximus, gluteus medius, tensor fascia lata) EMG amplitude ratios among subjects with low or high relative femoral anteversion. Data were collected during the performance of a non-weight bearing, non-sagittal plane maximal volitional effort isometric combined hip abduction-external rotation maneuver. Eighteen nonimpaired athletically active females participated in this surface EMG study. Medial hip rotation (relative femoral anteversion estimate) was measured with a handheld goniometer. Subjects were grouped by medial hip rotation displacement (group 1 < or = 42 degrees =36.1+/-7 degrees and group 2 > 42 degrees =52.7+/-7 degrees ) for statistical analysis (Mann Whitney U-tests, p < 0.05). Group 2 had decreased VM (42+/-23% vs. 69+/-30%, U=19, p=0.034) and GM (62+/-25% vs. 96+/-39%, U=19, p=0.034) normalized mean peak EMG amplitude:composite mean peak hip abductor EMG amplitude ratios compared to group 1. Decreased normalized VM (-27%) and GM (-34%) EMG amplitudes among subjects with increased relative femoral anteversion suggest reduced dynamic frontal and transverse plane femoral control from these muscles, possibly contributing to the increased incidence of non-contact knee injury observed among athletic females.

Adult↗

PubMed2003

Tibial fixation comparison of semitendinosus-bone composite allografts fixed with bioabsorbable screws and bone-patella tendon-bone grafts fixed with titanium screws.

Tibial fixation remains the weak link of ACL reconstruction over the first 8-12 weeks postoperatively. This study compared the biomechanical properties of tibial fixation for a bone-patellar tendon-bone (BPTB) graft and a novel semitendinosus-bone composite (SBC) allograft with mixed cortical-cancellous bone dowels at each end. Seven paired, fresh frozen cadaveric knees (20-45 years) were stripped of all soft tissue attachments and randomly assigned to receive either the BPTB graft or SBC allograft. Grafts were placed into tibial tunnels via a standard protocol and secured with either a 10 mmx28 mm bioabsorbable (SBC) or titanium (BPTB) screw. Grafts were cycled ten times in a servo hydraulic device from 10-50 N prior to pull to failure testing at a rate of 20 mm/min with the force vector aligned with the tibial tunnel ("worst case scenario"). Wilcoxon Signed Rank Tests were used to evaluate biomechanical differences between graft types ( p<0.05). Tibial bone mineral density and interference screw insertion torque were statistically equivalent between graft types. The mode of failure for all constructs was direct screw and graft construct pullout from the tibial tunnel. Significant differences were not observed between graft types for maximum load at failure strength (BPTB=620.8+/-209 N vs. SBC=601.2+/-140 N, p=0.74) or stiffness (BPTB=69.8 N/mm+/-29 N/mm vs SBC=47.1+/-31.6 N/mm, p=0.24). The SBC allograft yielded significantly more displacement prior to failure than the BPTB graft (15.1+/-4.9 mm vs 9.2+/-1.3 mm, p=0.04). Increased construct displacement appeared to be due to fixation failure, with some evidence of graft tissue tearing around the sutures: Bioabsorbable screw (10 x 28 mm) fixation of the SBC allograft produced unacceptable displacement levels during testing. Further study is recommended using a titanium interference screw or a longer bioabsorbable screw for SBC graft fixation under cyclic loading conditions.

Absorbable Implants↗

PubMed2003

Two-year outcomes following ACL reconstruction with allograft tibialis anterior tendons: a retrospective study.

The outcomes of 18 patients (11 females, 7 males; age, 40.4+/-11 years) at 2 years after ACL reconstruction with cryopreserved tibialis anterior allografts using a double bundle technique are presented. Most subjects (72%) described themselves as being moderately active before surgery. After providing written informed consent, subjects completed the 2000 IKDC Knee Form, underwent arthrometric knee measurements, and performed one-leg hop and isokinetic quadriceps and hamstring torque tests (60 degrees /s). Ninety-four percent (17/18) of the subjects had normal or near-normal grades for manual knee ligament tests. Knee arthrometry measurements revealed a mean 1.1-mm involved side increase at 134 N (8.9+/-2 mm vs 7.8+/-3 mm) and a 2-mm involved side increase during manual maximum testing (11.3+/-2 mm vs 9.3+/-3 mm). Group means revealed active knee flexion (136+/-8 degrees vs 139+/-6 degrees ) and knee hyper-extension (3+/-2 degrees vs 5+/-2 degrees ), which were slightly reduced at the involved knee. One-leg hop testing revealed a 15% mean deficit at the involved side (0.81+/-0.3 m vs 0.95+/-0.3 m). Isokinetic testing revealed an 11% mean deficit at the involved side (143.4+/-60 Nm vs 161.8+/-54 Nm) for the quadriceps and 7% greater strength at the involved side (105.9+/-35 Nm vs 98.8+/-35 Nm) for the hamstrings. Side-to-side comparisons revealed that many patients displayed less than normal quadriceps femoris torque (72%, 13/18), hamstring torque (28%, 5/18) and hop test (28%, 5/18) performance. Moderate positive correlations existed between involved side quadriceps ( r=0.80) and hamstring ( r=0.83) torque/bodyweight and hop test performance. Scores were 77.6+/-21 (range 28.7-100) and 78.1+/-16 (range 41.7-100) for the 2000 IKDC Subjective Knee Evaluation and Health Assessment forms. Most subjects (83%, 15/18) rated their current function at >or=91% of pre-injury levels and all subjects continued to participate at their pre-injury perceived activity level. At 2 years after ACL reconstruction with tibialis anterior allografts, this subject group displayed satisfactory functional outcomes. Tibialis anterior allograft use provides an effective ACL reconstruction alternative, particularly for older individuals who want to continue recreational sports.

Adult↗

PubMed2001

Delayed gastrocnemius muscle response to sudden perturbation in rehabilitated patients with anterior cruciate ligament reconstruction.

This nonrandomized, posttest-only comparison between two experimental groups and a control group compared the lower extremity muscle activation latencies of patients following rehabilitated unilateral anterior cruciate ligament (ACL) reconstruction (allograft or autograft bone-patellar tendon-bone tissue) and normal control subjects. Twenty-three subjects (seven allograft, eight autograft, eight normal control) of similar age, height, weight, isokinetic knee extensor, and flexor peak torque/bodyweight, functional capability (single leg broad jump and single leg vertical jump) and recreational activity level participated in this study. Experimental group subjects were 21.3+/-5 months (allograft) and 27.6+/-10 months (autograft) after surgery. Kinematic and electromyographic data were sampled during ten randomly timed unilateral perturbations. Experimental group gastrocnemius latencies were delayed (allograft 59.5+/-25 ms, autograft 69+/-20 ms) compared to the control group (31.8+/-11 ms). The allograft (r=0.80) and autograft (r=0.40) unilateral ACL reconstruction groups displayed moderate and weak positive relationships between anterior knee laxity and knee angular displacements following perturbation, respectively. Control group subjects did not display significant relationships between these variables (r=-0.07). In the allograft group there was also a moderate inverse relationship between gastrocnemius latency and knee angular displacement following perturbation (r=-72). The autograft (r=-0.06) and control (r=-0.21) groups did not show similar relationships between these variables. Delayed gastrocnemius latencies for the experimental groups suggested prolonged neuromuscular deficits during weight-bearing dynamic knee stabilization. Knee angular displacement magnitude following sudden perturbation was related more strongly to knee laxity and gastrocnemius latency among subjects who had undergone ACL reconstruction using allograft bone-patellar tendon-bone tissue.

Adult↗

PubMed2001

Long-term quadriceps femoris functional deficits following intramedullary nailing of isolated tibial fractures.

This retrospective study assessed 5 male and 5 female patients, age 35.1+/-16 years, height 171.8+/-12 cm, and weight 75.5+/-18 kg (mean+/-SD) who were more than 1 year post isolated tibial fracture (18+/-6 months) and had been treated with an intramedullary tibial nail. Subjects completed a 12-question visual analog scale, a physical symptom and activity of daily living survey, and were also tested for bilateral isokinetic (60 degrees/s) quadriceps femoris and hamstring strength. Knee pain during activity, stiffness, swelling, and buckling were the primary symptomatic complaints. Perceived functional task deficits were greatest for climbing or descending stairs, pivoting, squatting, and walking on uneven surfaces. Involved lower extremity knee extensor and flexor torque production deficits were 25% and 17%, respectively. Early rehabilitation focuses on maintaining adequate operative site bony fixation while providing controlled, progressive, and regular biomechanical loading to restore functionally competent tissue. Following adequate fracture healing, greater emphasis should be placed on lower extremity functional recovery including commonly performed activities of daily living and other functional tasks that are relevant to the patient's disability level. A cyclic rehabilitation program that progresses the weight-bearing environment to facilitate bone and soft tissue healing and neuromuscular re-education is proposed.

Adult↗

PubMed2001

The meniscus: review of basic principles with application to surgery and rehabilitation.

OBJECTIVE: To review basic meniscal anatomy, histology, and biomechanical principles as they apply to surgery and rehabilitation. DATA SOURCES: We searched MEDLINE and CINAHL for the years 1960-1999 using the terms meniscus,surgery,rehabilitation,meniscal repair, and arthroscopy. DATA SYNTHESIS: Injuries to a healthy meniscus are usually produced by a compressive force coupled with transverse-plane tibiofemoral rotation as the knee moves from flexion to extension during rapid cutting or pivoting. The goal of meniscal surgery is to restore a functional meniscus to prevent the development of degenerative osteoarthritis in the involved knee. The goal of rehabilitation is to restore patient function based on individual needs, considering the type of surgical procedure, which meniscus was repaired, the presence of coexisting knee pathology (particularly ligamentous laxity or articular cartilage degeneration), the type of meniscal tear, the patient's age, preoperative knee status (including time between injury and surgery), decreased range of motion or strength, and the patient's athletic expectations and motivations. Progressive weight bearing and joint stress are necessary to enhance the functionality of the meniscal repair; however, excessive shear forces may be disruptive. Prolonged knee immobilization after surgery can result in the rapid development of muscular atrophy and greater delays in functional recovery. CONCLUSIONS/RECOMMENDATIONS: Accelerated joint mobility and weight-bearing components of rehabilitation protocols represent the confidence placed in innovative surgical fixation methods. After wound healing, an aquatic therapy environment may be ideal during all phases of rehabilitation after meniscal surgery (regardless of the exact procedure), providing the advantages of controlled weight bearing and mobility progressions. Well-designed, controlled, longitudinal outcome studies for patients who have undergone meniscectomy, meniscal repair, or meniscal reconstruction are lacking.

Journal Article↗

PubMed2000

Soft tissue injuries to USA paralympians at the 1996 summer games.

OBJECTIVE: To report the soft tissue injuries sustained by the members of four disabled sports organizations (DSOs) who competed as the USA Team at the 1996 Paralympic Games. SETTING: 1996 Paralympic Games, Atlanta, Georgia. METHODS: Soft tissue (strain, sprain, tendonitis, bursitis, or contusion) injury frequencies sustained by Disabled Sports USA (DSUSA, n = 66), the United States Association for Blind Athletes (USABA, n = 53), the United States Cerebral Palsy Athletic Association (USCPAA, n = 56), and Wheelchair Sports USA (WSUSA, n = 129) athletes were compared by body region with chi-square tests (p<.05) and standardized residual assessment. RESULTS: A total of 254 soft tissue injuries (67% acute onset, 170/254) were sustained by the participant DSO members. Statistical design limitations and poor USCPAA athlete homogeneity prompted their exclusion from group comparisons (descriptive results are reported). The most common injury regions for specific DSOs were shoulder (26%), hip-thigh (14%), and ankle (12%) for DSUSA; hip-thigh (21%), cervicothoracic region (19%), and shoulder (17%) for USABA; lumbar region (14%), foot-toe (13%), and ankle (9%) for USCPAA; and shoulder (18%), arm-elbow (12%), forearm-wrist (12%), and lumbar region (9%) for USUSA. Chi-square residual analysis showed that the USABA athletes contributed more to cervicothoracic and lower leg region injury frequencies than DSUSA or WSUSA athletes. The WSUSA athletes contributed more to elbow-arm and forearm-wrist region injury frequencies than DSUSA or USABA athletes. The DSUSA athletes contributed more to ankle region injury frequencies than USABA or WSUSA athletes. CONCLUSIONS: Differences in soft tissue injury frequency among athletes of differing DSOs suggest that the competitive use of adaptive or assistive devices, in combination with sport-specific stressors and the athletes' disabilities, is related to the development of predictable soft tissue injury patterns. The decreased incidence of shoulder injury among WSUSA athletes suggests that the injury prevention advice provided by previous studies is being implemented among athletes at this competitive level. The increased incidence of ankle injuries among DSUSA athletes suggests lower extremity load imbalances (prosthetic vs. uninvolved) during running. The increased incidence of lower leg injuries among USABA athletes suggests "overuse" injury patterns typical of nondisabled runners, or inadvertent contacts (contused shins), whereas the increased incidence of cervicothoracic injuries suggests injuries related to falls, "near falls," or sudden directional changes prompted by guidance aids.

Athletic Injuries↗

PubMed2000

Preserving transfer independence among individuals with spinal cord injury.

STUDY DESIGN: Literature review. OBJECTIVES: Upper extremity (UE) joint degeneration, particularly at the shoulder, detrimentally influences functional independence, quality of life, cardiovascular disease risk, and life expectancy of individuals following spinal cord injury (SCI). This review (1) describes UE use for transfers among individuals with SCI; (2) describes contributing factors associated with UE joint degeneration and loss of transfer independence; (3) summarizes and identifies gaps in existing research; and (4) provides suggestions for future research. RESULTS: Investigations of wheelchair transfer related UE joint and function preservation among individuals with SCI should consider factors including age and length of time from SCI onset, interface between subject-wheelchair, pain, shoulder joint range of motion (ROM) and muscle strength deficiencies or imbalances, exercise capacity and tolerance for the physical strain of activities of daily living (ADL), body mass and composition, previous UE injury or disease history, and transfer techniques. Existing studies of transfers among individuals with SCI have relied on small groups of either asymptomatic or non-impaired subjects, with minimal integration of kinematic, kinetic and electromyographic data. Descriptions of UE joint ROM, forces, and moments produced during transfers are lacking. CONCLUSIONS: Biomechanical measurement and computer modeling have provided increasingly accurate tools for acquiring the data needed to guide intervention planning to prevent UE joint degeneration and preserve function among individuals with SCI. The identification of stressful sub-components during transfers will enable intervening clinicians and engineers who design and modify assistive and adaptive devices to better serve individuals with SCI.

Activities of Daily Living↗

PubMed1999

Hamstring extensibility and transverse plane knee control relationship in athletic women.

Athletic women are at particular risk for sustaining a non-contact anterior cruciate ligament (ACL) injury. The hamstrings are vital to providing dynamic knee motion control in the sagittal and transverse planes during running stance, and some have suggested this function is enhanced when they are less extensible. This study attempted to determine the correlational relationships between hamstring extensibility and transverse plane knee kinematics and from these data to describe the dynamic transverse plane knee motion control capabilities of the hamstrings. Twenty normal athletic women (mean +/- SD; aged 21 +/- 1.6 years; height 163.3 +/- 5.7 cm; weight 60.1 +/- 3.6 kg) were evaluated for active hamstring extensibility and transverse plane knee kinematic relationships during crossover-cut stance phase. Following crossover-cut training (3 weeks) using the left (preferred) lower extremity as the stance limb, hamstring extensibility was measured. Following this, subjects were fitted with 9 retroreflective markers denoting the local segmental coordinate systems (3 markers each) of the left foot, leg and thigh. Kinematic (3-dimensional, four phase-locked cameras, 200 Hz) knee and ankle data were sampled and analyzed. Descriptive statistics and Pearson correlations between hamstring extensibility and knee and ankle kinematic variables were calculated. Statistical significance was set at P < or = 0.05 with Bonferroni adjustments. Hamstring extensibility (12 degrees +/- 8 degrees terminal extension) revealed low but significant positive correlations with tibial external rotation (6 degrees +/- 10.7 degrees) at heelstrike (19.3 degrees +/- 8.5 degrees knee flexion) (r = 0.62, P = 0.004) and tibial internal rotation (-13 degrees +/- 8.4 degrees) at peak knee flexion (57.8 degrees +/- 9.3 degrees) following heelstrike (r = 0.47, P = 0.01). Increased hamstring extensibility resulted in increased tibial external rotation at heelstrike and decreased tibial internal rotation at peak knee flexion. Increased hamstring extensibility may improve knee extensor efficiency at heelstrike by enabling greater tibial external rotation and protect the ACL at peak knee flexion by decreasing the tibial internal rotation magnitude.

Adult↗

PubMed1999

Rehabilitation complications following knee surgery.

When pain and effusion have been minimized and patients assume appropriate knee posture at rest and during exercise, the extent of postinjury or postoperative quadriceps femoris neuromuscular inhibition and avoidance during locomotion is reduced. Restoring normal lower-extremity ROM and musculotendinous extensibility (with consideration for biarticular muscles) is foundational to the implementation of an exercise program that integrates the trunk, hip, and ankle muscles into dynamic knee-stabilization challenges while addressing isolated quadriceps femoris deficiencies. Cardiovascular conditioning should be addressed as early as feasible. Although programs generally address anaerobic and aerobic energy systems, increasing patients' fatigue resistance, as evidenced by prolonged maintenance of appropriate functional exercise techniques and body control without verbalized discomfort or observed movement-avoidance patterns, ensures therapists that neuromuscular responsiveness for dynamic knee stabilization is improving.

Exercise Therapy↗

PubMed1999

An anatomic evaluation of T-Fix suture device placement for arthroscopic all-inside meniscal repair.

This investigation documented the locations of endoscopically applied T-Fix suture devices (Acufex Microsurgical, Mansfield, MA) placed in six fresh-frozen cadaveric knees (age, 60 to 72 years) in relationship to the joint capsule, and adjacent neurovascular and musculotendinous structures. Five T-Fix devices were placed in the posterior meniscal regions at approximately 20 degree intervals. Gross dissection enabled T-Fix bar and suture placement identification. Fifty total devices were placed (23 medially and 27 laterally). Lateral: None of the devices penetrated more superficially than the deepest capsular layer (layer III). Six of the 27 devices placed at the posterior horn of the lateral meniscus pierced the popliteus tendon. None of the bars pierced the lateral collateral ligament (layer III). All devices placed at the posterolateral knee were outside the arcuate ligament (layer III) but inside the fabellofibular ligament (layer II). Medial: Seven of the 23 devices pierced the deep medial collateral ligament (MCL, layer III), and 4 pierced the superficial MCL (layer II). Three devices pierced the sartorius tendon (layer I) and one pierced the gracilis tendon (layer II). None of the medial devices created a plicating effect on the posterior capsule. None of the devices were placed near neurovascular structures. Devices placed within the posterior meniscal horns had a > or =1.5-cm buffer zone from the popliteal neurovascular bundle. Most bars (36 of 50) were anchored to the capsular layer (layer III) after piercing the meniscocapsular junction (layer II). T-Fix devices simulating arthroscopic all-inside meniscal repair provided well-positioned, solid suture anchorage through the junction with no neurovascular involvement. Care needs to be taken when placing lateral (popliteus muscle) and medial (gracilis, sartorius tendons and superficial MCL) devices to avoid possible soft tissue tenodesis.

Aged↗

PubMed1999

The radiographic position of medial and lateral meniscal horns as a basis for meniscal reconstruction.

This investigation attempted to determine the radiographic position of human meniscal horn bony insertion sites. This information would prove vital for anatomically correct osseous tunnel placement necessary for the restoration of a functional meniscus after reconstructive surgery. The native bony insertion sites of the medial and lateral meniscus in 13 fresh-frozen human cadaver knees were radiographically examined. After insertion site outline with 22-gauge fine wire, anteroposterior and lateral radiographs were obtained. Radiographic landmarks were then described in detail. Each meniscal horn was found to have a distinct bony insertion site with characteristic and consistent radiographic landmarks defining its margins. Using an arthroscopic guide, 3/32-inch fine wires were drilled into the center of the lateral (5 specimens) and medial (5 specimens) meniscal horns to validate these locations and to establish the clinical usefulness of these measures. Improved understanding of meniscal horn insertion site locations should improve osseous tunnel placements during meniscal transplantation. In the presence of a properly sized allograft, anatomically correct tunnel placement increases the likelihood of restoring normal meniscal function.

Arthroscopy↗

PubMed1999

Electromyographic timing analysis of forward and backward cycling.

PURPOSE: Backward walking to running progressions are becoming a popular, nontraditional component of functional knee rehabilitation programs. The purpose of this electromyographic (EMG) and motion analysis study was to compare the activation duration of the vastus medialis, vastus lateralis, rectus femoris, medial hamstrings, lateral hamstring, tibialis anterior, and gastrocnemius muscles during forward and backward cycling. We hypothesized that the hamstrings would demonstrate greater activation duration during backward cycling. METHODS: The right lower extremity of 12 healthy subjects (6 male and 6 female) was instrumented with surface EMG electrodes and retroreflective markers to confirm lower extremity kinematic consistency between conditions. RESULTS: Statistical analysis of hip, knee, and ankle kinematics (200 Hz sampling rate) and gender failed to reveal significant differences between conditions (P > 0.05). Quadrant analysis of muscle activation duration with Bonferroni corrections for multiple comparisons revealed that medial and lateral hamstring activation duration was greater during the early recovery phase (quadrant III) of backward cycling than forward cycling (P < 0.00156). Rectus femoris activation duration was greater in the early propulsive phase of backward cycling (quadrant 1) (P < 0.00156) and in the early recovery phase of forward cycling (quadrant III) (P < 0.00156). CONCLUSIONS: These findings lend support for the use of backward cycling during the early recovery phase (quadrant III) to achieve a selective hamstring muscle response of relatively decreased patellofemoral stress and anterior cruciate ligament strain.

Adult↗

PubMed1999

Shoulder proprioception: latent muscle reaction times.

PURPOSE: The purpose of this study was to identify electromyographic (EMG) differences in the latent muscle reaction timing (LMRT) of the rotator cuff between trained overhead throwers and control subjects in response to sudden internal rotation perturbation (P < or = 0.05). METHODS: Subjects included 15 trained overhead throwers (male intercollegiate baseball players) and 15 untrained subjects (males not active in competitive throwing sports). Subjects were tested while seated, with their dominant glenohumeral joint positioned in 90 degrees abduction/external rotation (scapular plane), their elbow flexed to 90 degrees, and their forearm placed in the perturbation device. Rotator cuff LMRT was assessed as they tried to decelerate a variably timed, sudden internal rotation force. EMG sampling (2000 Hz, 2-s duration) began immediately before perturbation. RESULTS: Trained throwers had slower infraspinatus (P = 0.011) and teres minor (P = 0.024) LMRT and decreased supraspinatus (P = 0.001) and posterior deltoid (P = 0.0001) muscle activation duration compared with control subjects. CONCLUSIONS: These results suggest that the rotator cuff muscles of trained throwers may be downregulated in response to sudden internal rotation perturbation. Although these adaptations would enable greater internal rotation velocities during overhead throwing, they may also contribute to glenohumeral joint pathology. The identification of changes in rotator cuff LMRT in response to sudden internal rotation perturbation suggests an area of acquired neuromuscular imbalance warranting consideration by those involved in the rehabilitation and conditioning of the overhead throwing athlete.

Adolescent↗

PubMed1999

Relationship between ankle invertor H-reflexes and acute swelling induced by inversion ankle sprain.

STUDY DESIGN: Single group, post-test design using the uninvolved lower extremity as the experimental control. OBJECTIVES: To determine relationships between ankle swelling and flexor digitorum longus and peroneus longus H-reflex amplitude and latency. BACKGROUND: Primary capsuloligamentous injury, neural injury, and joint effusion and swelling may contribute to H-reflex changes following inversion ankle sprain. The relationship between ankle swelling and invertor or evertor H-reflexes has not been reported. METHODS AND MEASURES: Fifteen subjects with acute grade I or II inversion ankle sprains (mean +/- SD) 6.5 +/- 3 days after onset participated in this study. Swelling was estimated using a tape measure and the figure-of-eight girth assessment method. H-reflexes were determined using standard techniques. Paired t-tests were used to compare mean differences in ankle girth (swelling) and ankle invertor or evertor H-reflex amplitude and latency between the involved and uninvolved limbs. Pearson product moment correlations were used to assess relationships between swelling and H-reflex variables. RESULTS: Involved limb ankle girth was increased with respect to the uninvolved limb (1.5 +/- 0.9 cm) and the involved ankle flexor digitorum longus latency was delayed (0.72 +/- 0.7 ms). There was a moderate positive association (r = 0.73) between the latency delay in the involved ankle flexor digitorum longus and swelling. There were no significant differences in H-reflex amplitude and peroneus longus latency between ankles. CONCLUSIONS: Grade I or II inversion sprains and the related swelling appear to delay involved ankle flexor digitorum longus latency to a greater extent than peroneus longus latency. Clinicians need to direct greater attention to the ankle invertors when designing and implementing ankle rehabilitation programs, particularly during the swelling management phase of treatment.

Acute Disease↗

PubMed1999

Effects of a 2-hour cheerleading practice on dynamic postural stability, knee laxity, and hamstring extensibility.

STUDY DESIGN: One group; pretest, posttest design. OBJECTIVE: To assess the effect of a 2-hour cheerleading practice on the anterior knee laxity, hamstring extensibility, and dynamic postural stability (preferred stance leg during vision-denied unilateral stance) of 17 nonimpaired members of a college cheerleading team (8 females, 9 males; 18-25 years old). BACKGROUND: Anterior knee laxity and hamstring extensibility increase following exercise. The relationship between exercise induced anterior knee laxity, hamstring extensibility, and dynamic postural stability, however, has not been examined. METHODS AND MEASURES: Pre- and postpractice measurements were compared using paired t tests and Bonferroni's correction for multiple comparisons. A 3 x 2 analysis of variance (force level applied to the arthrometer by condition) and Tukey honest significant difference post hoc test were used to evaluate specific arthrometer force level by condition effects (P < .05). RESULTS: Mean laxity at 133 N and hamstring extensibility increased (mean +/- SD) 1.5 +/- 1 mm and 3 +/- 4 degrees, respectively, following practice. Mean medial-lateral stabiliometer platform angulation (frontal plane position) moved medially following practice (2.9 +/- 3 degrees) and produced a weak correlation with increased knee laxity (r = 0.58). Hamstring extensibility did not significantly relate to stabiliometry or knee laxity variables. CONCLUSIONS: The relationship between the medially directed platform angulation and the increase in anterior knee laxity following cheerleading practice suggests a relationship between subtalar joint position and anterior cruciate ligament strain.

Adolescent↗

PubMed1999

Does pulsed low intensity ultrasound allow early return to normal activities when treating stress fractures? A review of one tarsal navicular and eight tibial stress fractures.

We sought to evaluate the efficacy of daily pulsed low intensity ultrasound (LIUS) with early return to activities for the treatment of lower extremity stress fractures. Eight patients (2 males, 6 females) with radiographic and bone scan confirmed tibial stress fractures participated in this study. Additionally, a case report of a tarsal navicular stress fracture is described. All patients except one were involved in athletics. Prior to the study, subjects completed a 5 question, 10 cm visual analog scale (VAS) regarding pain level (10 = extreme pain, 1 = no pain) and were assessed for functional performance. Subjects received 20-minute LIUS treatments 5 times a week for 4 weeks. Subjects maintained all functional activities during the treatment period. Seven patients with posterior-medial stress fractures participated without a brace. Subjects were re-tested after 4 weeks of treatment. Mann-Whitney U tests (VAS data) and paired t-tests (functional tests) assessed statistical significance (p<0.05). Although the intensity of practice was diminished in some instances, no time off from competitive sports was prescribed for the patients with the tibial stress fractures. The patient with the anterior tibial stress fracture underwent tibial intramedullary nailing at the conclusion of a season of play. In this uncontrolled experience, treatment of tibial stress fractures with daily pulsed LIUS was effective in pain relief and early return to vigorous activity without bracing for the patients with posterior-medial stress fractures.

Basketball↗