PubMed Health⌕ Search

Biomedical subjects

W E Garrett

Publications and source records attributed to W E Garrett.

At least 19 recordsLinked to original sources
PubMed2005

Injury history as a risk factor for incident injury in youth soccer.

OBJECTIVES: To determine if athletes with a self reported history of previous injury have a higher incident injury rate than athletes without a self reported injury history. METHODS: A prospective cohort study of Classic League soccer players playing at the level under 12 through under 18. Injury history forms were mailed to all registering Classic League soccer players in the North Carolina Youth Soccer Association during 1997-2000 (n = 7000); 1483 (19%) returned the baseline questionnaire and were followed up for injuries. RESULTS: There were 5139 player-seasons of follow up and an estimated 171 957 athlete-exposures. More than half self reported an injury history (59.7%). Overall, the unadjusted incidence rate was 4.6 (95% confidence interval (CI) 4.3 to 4.9) incident injuries per 1000 athlete-exposures. Multivariate generalised Poisson regression modelling indicated that players with one previous injury had a twofold greater risk of incident injury (IRR = 2.6; 95% CI 2.0 to 3.3), and those with two or more previous injuries had a threefold greater risk of incident injury (IRR = 3.0; 95% CI 2.3 to 3.8) compared with athletes with no previous injuries. CONCLUSIONS: Injury history was associated with an increased injury rate. This suggests that, even in these youth soccer players, those with an injury history may be at higher risk.

Adolescent↗
PubMed2001

MR findings in athletes with pubalgia.

OBJECTIVE: To describe the MR findings in athletes with pubalgia. DESIGN AND PATIENTS: Pelvic MR images of 32 athletes (30 men, 2 women) with pubalgia were studied. T1-weighted and T2-weighted (SE and FSE) and STIR images in the axial and coronal planes were obtained on a 1.5-T system. Images were reviewed for general pelvic pathology. Special attention was given to the pubic symphysis, groin and pelvic musculature, and to the abdominal wall musculature. RESULTS: Thirty surgically confirmed cases comprise the study group. Abnormalities in the following were found: pubic symphysis (21/30), abdominal wall (27/30), groin musculature, including rectus abdominis (21/30), pectineus (6/30), and adductor muscle group (18/30). CONCLUSIONS: Pubalgia is a complex process which is frequently multifactorial. The MRI findings can alter the surgical approach.

Adolescent↗
PubMed2001

A comparison of knee joint motion patterns between men and women in selected athletic tasks.

BACKGROUND: Women have higher non-contact anterior cruciate ligament injury rate than men do in sport activities. Non-contact anterior cruciate ligament injuries frequently occur in sports requiring cutting tasks. Alternated motor control strategies have identified as a potential risk factor for the non-contact anterior cruciate ligament injuries. The purpose of this study was to compare the patterns of knee kinematics and electromyographic activities in running, side-cutting, and cross-cutting between men and women recreational athletes. METHODS: Three-dimensional kinematic data of the knee and electromyographic data of selected muscles across the knee joint were collected for 11 men and 9 women recreational athletes in running, side-cutting, and cross-cutting. Regression analyses with dummy variables for comparison of knee motion patterns between men and women. RESULTS: Women tend to have less knee flexion angles, more knee valgus angles, greater quadriceps activation, and lower hamstring activation in comparison to men during the stance phase of each of the three athletic tasks. Literatures suggest these alternated knee motion patterns of women tend to increase the load on the anterior cruciate ligament. CONCLUSION: Women on average may have certain motor control strategies that may alter their knee motion patterns. Women's altered knee motion patterns may tend to increase the load on the anterior cruciate ligament in the selected athletic tasks, which may contribute to the increased anterior cruciate ligament injury rate among women. RELEVANCE: Non-contact anterior cruciate ligament injuries frequently occur in sports. Altered motor control strategies and lower extremity motion patterns are likely to play an important role in non-contact anterior cruciate ligament injuries. Non-contact anterior cruciate ligament injuries may be prevented by correcting altered motor control strategies and associated lower extremity motion patterns through certain training programs.

Electromyography↗
PubMed2001

Heading and head injuries in soccer.

In the world of sports, soccer is unique because of the purposeful use of the unprotected head for controlling and advancing the ball. This skill obviously places the player at risk of head injury and the game does carry some risk. Head injury can be a result of contact of the head with another head (or other body parts), ground, goal post, other unknown objects or even the ball. Such impacts can lead to contusions, fractures, eye injuries, concussions or even, in rare cases, death. Coaches, players, parents and physicians are rightly concerned about the risk of head injury in soccer. Current research shows that selected soccer players have some degree of cognitive dysfunction. It is important to determine the reasons behind such deficits. Purposeful heading has been blamed, but a closer look at the studies that focus on heading has revealed methodological concerns that question the validity of blaming purposeful heading of the ball. The player's history and age (did they play when the ball was leather and could absorb significant amounts of water), alcohol intake, drug intake, learning disabilities, concussion definition and control group use/composition are all factors that cloud the ability to blame purposeful heading. What does seem clear is that a player's history of concussive episodes is a more likely explanation for cognitive deficits. While it is likely that the subconcussive impact of purposeful heading is a doubtful factor in the noted deficits, it is unknown whether multiple subconcussive impacts might have some lingering effects. In addition, it is unknown whether the noted deficits have any affect on daily life. Proper instruction in the technique is critical because if the ball contacts an unprepared head (as in accidental head-ball contacts), the potential for serious injury is possible. To further our understanding of the relationship of heading, head injury and cognitive deficits, we need to: learn more about the actual impact of a ball on the head, verify the exposure to heading at all ages and competitive levels, determine stable estimates of concussive injury rates across the soccer spectrum, conduct prospective longitudinal studies on soccer players focusing on exposure, injury and cognition, and determine the minimum safe age to begin instruction on the skill of heading. Only then will we be able to speak with some authority on the issue of heading and head injuries in soccer.

Biomechanical Phenomena↗
PubMed2000

The anterior cruciate ligament enigma. Injury mechanisms and prevention.

The reasons for the higher frequency of anterior cruciate ligament injuries in women are largely conjecture. These injuries may result from direct contact or, more frequently, from no direct contact to the knee during activities that most athletes consider routine to their sport. This implies that there are intrinsic factors that lead to anterior cruciate ligament rupture. For the anterior cruciate ligament to tear, there must be excess anterior tibial translation or rotation of the femur on the tibia. In the former case, the tibia can move anteriorly during quadriceps activation that is not counterbalanced by hamstring activation. Patients describe their injury as occurring when landing, stopping, or when planting to change directions. The knee typically was near full extension. Mechanically, the angle of the patellar tendon and tibial shaft increases as the knee approaches full extension. This gives a mechanical advantage to the quadriceps. During cutting maneuvers, athletes tend to cut with a knee near extension (0 degree-20 degrees) when the quadriceps are active and the hamstrings are neither very active nor at a knee flexion angle that offers much of a mechanical advantage. In performing cutting and landing maneuvers, women tend to perform the activities more erect; that is, with their knee and hips closer to extension. One possible factor to help reduce the frequency of anterior cruciate ligament injuries in women may be in proper instruction for performing cutting and landing maneuvers which will lower their center of gravity thereby denying the quadriceps the opportunity to shift the tibia anteriorly.

Anterior Cruciate Ligament Injuries↗
PubMed2000

Mechanisms of anterior cruciate ligament injury.

This study examined the mechanisms of anterior cruciate ligament (ACL) injury. In the first part of the study, using a comprehensive, standardized questionnaire, 89 athletes (100 knees) were interviewed about the events surrounding their ACL injury. A noncontact mechanism was reported in 71 (72%) knees and a contact injury in 28 (28%) knees; one patient was unsure if there was any contact. Most of the injuries were sustained at footstrike with the knee close to full extension. Noncontact mechanisms were classified as sudden deceleration prior to a change of direction or landing motion, while contact injuries occurred as a result of valgus collapse of the knee. Hamstring flexibility parameters revealed a statistically higher level of laxity in the injured athletes compared with a matched group of 28 controls. In the second part of the study, videotapes of 27 separate ACL disruptions were reviewed and confirmed that most noncontact injuries occur with the knee close to extension during a sharp deceleration or landing maneuver. Because the knee is in a position to allow the extensor mechanism to strain the ACL and maximum, eccentric muscle force conditions usually apply, the quadriceps may play an important role in ACL disruption. Passive protection of the ACL by the hamstring muscles may be reduced in patients with above-average flexibility.

Anterior Cruciate Ligament Injuries↗
PubMed2000

Development of a virtual reality arthroscopic knee simulator.

The virtual reality arthroscopic knee simulator (VR-AKS) consists of a computer platform, a video display, and two force-feedback (haptic) interfaces which also monitor the position of the instruments in the user's hands. The forces that the user would normally apply to the lower limb during arthroscopy are directed through an instrumented surrogate leg. Proprietary software furnishes the mathematical representation of the physical world and replicates the visual, mechanical, and behavioral aspects of the knee while task-oriented programs monitor and record specific areas of user performance. A prototype has demonstrated the feasibility of the system and work on the first, fully functional simulator will begin soon.

Arthroscopy↗
PubMed1999

Tibia and fibula fractures in soccer players.

We performed a retrospective review of 31 athletes who sustained a fracture of the lower leg from a direct blow while playing soccer. Fifteen fractures involved both the tibia and fibula 11 only the tibia, and 5 only the fibula. Information was collected using a standardized questionnaire. The mean follow-up from the time of injury was 30 months. Injuries typically occurred in young, competitive athletes during game situations. The mechanisms were broadly classified into several categories: contact during a slide tackle (13, 42%), a collision with the goalkeeper (8, 26%), two opposing players colliding while swinging for a loose ball (7, 23%), or a player being kicked by a standing opponent (3, 10%). The majority of fractures (26, 90%) occurred while the athletes were wearing shin guards. The point of impact was with the shin guard prior to the fracture in 16 cases (62%). Return to competitive soccer averaged 40 weeks for combined tibia and fibula fractures, 35 weeks for isolated tibia fractures, and 18 weeks for isolated fibula fractures. Injuries were associated with a high incidence of major complications (12 out of 31, 39%), especially in concurrent tibia and fibula fractures (8 out of 15, 50%). These findings suggest that lower leg fractures in soccer players are serious injuries, often necessitating a prolonged recovery time. In addition, this study questions the ability of shin guards to protect against fractures.

Adolescent↗
PubMed1998

Mechanisms of injury of the anterior cruciate ligament in soccer players.

Despite the great amount of research that has been focused on the anterior cruciate ligament in recent years, relatively little is known about the exact mechanisms that cause these injuries. By defining the factors that contribute to these injury mechanisms in soccer players, the authors hope to facilitate appropriate training methods and work at preventing these serious injuries.

Anterior Cruciate Ligament Injuries↗
PubMed1998

Snapping popliteal tendon as a source of lateral knee pain.

A 25-year-old female patient underwent surgery for a history of pain and popping on the lateral aspect of her right knee. It was initially thought that the patient had iliotibial (IT) band syndrome which was refractory to conservative treatment. However, upon release of the IT band, the snapping which was audible and palpable pre-operatively was still present. Further exploration of the posterior-lateral aspect of the knee revealed that the popliteal tendon was snapping over the incisura poplitea extensoria on the lateral femoral condyle. Excision of the prominent portion of the articular ridge below the sulcus popliteus eliminated the snapping sensation. The patient has remained asymptomatic since surgery for the past 22 months.

Adult↗
PubMed1998

The influence of strain rate on the passive and stimulated engineering stress--large strain behavior of the rabbit tibialis anterior muscle.

The passive and stimulated engineering stress-large strain mechanical properties of skeletal muscle were measured at the midbelly of the rabbit tibialis anterior. The purpose of these experiments was to provide previously unavailable constitutive information based on the true geometry of the muscle and to determine the effect of strain rate on these responses. An apparatus including an ultrasound imager, high-speed digital imager, and a servohydraulic linear actuator was used to apply constant velocity deformations to the tibialis anterior of an anesthetized neurovascularly intact rabbit. The average isometric tetanic stress prior to elongation was 0.44 +/- 0.15 MPa. During elongation the average stimulated modulus was 0.97 +/- 0.34 MPa and was insensitive to rate of loading. The passive stress-strain responses showed a nonlinear stiffening response typical of biologic soft tissue. Both the passive and stimulated stress-strain responses were sensitive to strain rate over the range of strain rates (1 to 25 s-1). Smaller changes in average strain rate (1 to 10, and 10 to 25 s-1) did not produce statistically significant changes in these responses, particularly in the stimulated responses, which were less sensitive to average strain rate than the passive responses. This relative insensitivity to strain rate suggests that pseudoelastic functions generated from an appropriate strain rate test may be suitable for the characterization of the responses of muscle over a narrow range of strain rates, particularly in stimulated muscle.

Animals↗
PubMed1997

Stress fractures: general concepts.

This article is an overview of the general concepts about stress fractures, including history, epidemiology, and cause. The proper diagnosis, confirmation studies, and treatment regimens are presented. Finally, the timing of the athlete's return to sports, with stress fracture prevention measures are reviewed.

Athletic Injuries↗
PubMed1997

Comparison of synovial fluid cartilage marker concentrations and chondral damage assessed arthroscopically in acute knee injury.

OBJECTIVE: To examine the correlation between synovial fluid cartilage markers and degree of cartilage damage determined by arthroscopic evaluation in subjects with acute knee injury. DESIGN: Chondral damage was quantified using a validated arthroscopic scoring system in 20 subjects with effusive acute knee injuries of less then 4 months duration and no history or radiographic evidence of joint pathology. Levels of synovial fluid 3B3(-) neoepitope, 3B3(+) chondroitinase generated epitope of proteoglycan, keratan sulfate (KS) and hyaluronic acid (HA) were measured by competitive enzyme-linked immunosorbent assays using monoclonal antibodies 3B3 and 5D4. Total sulfated glycosaminoglycan (GAG) was measured by 1,9-dimethylmethylene blue colorimetric dye-binding assay. RESULTS: We found a dramatic decrease in levels of 3B3(-) (rs = -0.62, P = 0.004), and GAG (rs = -0.49, P = 0.03) with increasing chondral damage score; but no correlation of damage score with 3B3(+), KS or HA levels. CONCLUSION: These data reveal a change in cartilage metabolism within the first 4 months of symptomatic knee injury evinced by a significant inverse correlation of 3B3(-) and GAG levels to chondral lesion severity. These results suggest that serial measurement of these synovial fluid markers in the setting of acute knee injury could predict chondral lesion severity and aid in the decision to intervene surgically.

Acute Disease↗
PubMed1997

Function and biomechanics of tendons.

Tendon is a highly organized connective tissue joining muscle to bone, capable of resisting high tensile forces while transmitting forces from muscle to bone. The dense, regularly arranged collagenous tissue is made up of fibers, cells of various shapes and ground substance. The mechanical and physiological characteristics of collagen (nearly 85% of the dry weight of tendon) dictate the qualities of tendon. In addition, tendon is flexible so that it can bend at joints, as well as acting as a damping tissue to absorb shock and limit potential damage to muscle (1). Tendon also shows a degree of extensibility. If the strain used to stretch a tendon could be recovered, a beneficial elastic effect would be achieved. Muscles lengthen and shorten in a cyclical manner. During the lengthening period, elastic energy can be stored and used as elastic recoil. For example, the Achilles tendon is stretched late in the stance phase as the triceps surae muscles contract and the ankle dorsiflexes. Prior to plantarflexion, muscle activation ceases and stored energy helps to initiate planter flexion.

Adrenal Cortex Hormones↗