Anterior cruciate ligament injuries are occurring at a higher rate in female athletes compared with their male counterparts. Research in the area of anterior cruciate ligament injury has increasingly focused on the role of joint proprioception and muscle activity in promoting knee joint stability. We measured knee joint laxity, joint kinesthesia, lower extremity balance, the amount of time required to generate peak torque of the knee flexor and extensor musculature, and electromyographically assessed muscle activity in 34 healthy, collegiate-level athletes (average age, 19.6 +/- 1.5 years) who played soccer or basketball or both. Independent t-tests were used to determine significant sex differences. Results revealed that women inherently possess significantly greater knee joint laxity values, demonstrate a significantly longer time to detect the knee joint motion moving into extension, possess significantly superior single-legged balance ability, and produce significantly greater electromyographic peak amplitude and area of the lateral hamstring muscle subsequent to landing a jump. The excessive joint laxity of women appears to contribute to diminished joint proprioception, rendering the knee less sensitive to potentially damaging forces and possibly at risk for injury. Unable to rely on ligamentous structures, healthy female athletes appear to have adopted compensatory mechanisms of increased hamstring activity to achieve functional joint stabilization.

Objectives: To determine the effects of a 4-week balance training program during stance on a single leg. Background: Individuals who have experienced multiple episodes of inversion ankle sprains often participate in balance training programs. Balance training is performed to treat existing proprioceptive deficits and to restore ankle joint stability, presumably by retraining altered afferent neuromuscular pathways. The effectiveness of such programs on individuals with functionally unstable ankles has yet to be established.Methods and Measures: Prior to and following training, subjects with self-reported functionally unstable ankles (5 women and 8 men, mean age = 21.9 t 3.1 years) and nonimpaired subjects (6 women and 7 men, mean age = 212 t 2.5 years) completed a static balance assessment for both limbs as well as the ankle joint functional assessment tool questionnaire (AJFAT). The subjects from both groups participated in a unilateral, multilevel, static and dynamic balance training program 3 times a week for 4 weeks. Subjects from the experimental group trained only the involved limb, and the nonimpaired group trained a randomly selected limb. A stability index (SI) was calculated during the balance assessment to indicate the amount of platform motion. Compared to low stability indices, high stability indices indicate greater platform motion during stance and therefore l ess stability. Results: Following training, subjects from both groups demonstrated significant improvements in balance ability. When balance was assessed at a low resistance to platform tilt (stability level 21, the posttraining scores of both the subjects with unstable ankles (mean SI = 2.63 t 1.92) and the nonimpaired subjects (mean SI = 2.69 2 2.32) were significantly better than their pretraining scores (mean Sl s = 5.93 2 3.65 and 4.67 2 3.43, respectively). Assessed at a high resistance to platform tilt (stability level 6), the posttraining scores of both subjects with unstable ankles (mean SI = 1.27 t 0.66) and the nonimpaired subjects (mean SI = 1.37 + 0.66) were significantly better than their pretraining scores (mean Sl s = 2.30 + 1.88 and 2.04 + 1.43, respectively). Additionally, the posttraining AJFAT scores of subjects with unstable ankles (25.78 + 3.80) Functional instability of the ankle joint has been defined by Freeman7 as "a tendency for the foot to give way after an ankle sprain." Three factors thought to cause functional instability of the ankle joint are anatomic or mechanical instability, muscle weakness, and deficits in joint proprio~eption.'~ At this time, there are no objective data that conclusively show that muscle weakness is a viable explanation for functional ankle instability. However, the combination of mechanical instability and decreased neuromuscular control resulting from deficits in joint propriocep tion may result in functional instability of the ankle j~i n t .~J " J~J~ Deficits in ankle joint proprie ception with diminished neuromuscular control have been documented following ankle joint ligamentous ...

Proprioception and accompanying neuromuscular feedback mechanisms provide an important component for the establishment and maintenance of functional joint stability. Neuromuscular control and joint stabilisation is mediated primarily by the central nervous system. Multisite sensory input, originating from the somatosensory, visual and vestibular systems, is received and processed by the brain and spinal cord. The culmination of gathered and processed information results in conscious awareness of joint position and motion, unconscious joint stabilisation through protective spinal-mediated reflexes and the maintenance of posture and balance. Clinical research aimed at determining the effects of articular musculoskeletal injury, surgery and rehabilitation, on joint proprioception, neuromuscular control and balance has focused on the knee and ankle joints. Such studies have demonstrated alterations in proprioception subsequent to capsulo-ligamentous injury, partial restoration of proprioceptive acuity following ligamentous reconstruction, and have suggested beneficial proprioceptive changes resulting from comprehensive rehabilitation programmes.

The purpose of this study was to determine the proprioceptive effects of ankle bracing and taping. Proprioception was assessed in 26 subjects by evaluating ankle joint position sense, which was determined by the subjects' ability to actively reproduce a passively positioned joint angle. Testing was performed at positions of 30° of plantar flexion and 15° of inversion. Each subject underwent four trials at each test angle under three conditions: braced, taped, and control. For the plantar flexion test, both the braced condition and the taped condition significantly enhanced joint position sense when compared to the control condition. There was no significant difference between the braced and taped conditions. For the inversion test, the taped condition significantly enhanced joint position sense compared to the control condition. There was no significant difference between the braced and the control conditions or between the braced and the taped conditions. This study demonstrates that ankle bracing and taping improve joint position sense in the stable ankle.

Objective To provide certified athletic trainers (ATs) with recommendations and guidelines for the immediate management of patients with joint dislocations. Background One of the primary responsibilities of ATs is to provide immediate injury care for active individuals. Although ATs are confronted with managing patients who have many kinds of injuries, the onsite management of a joint dislocation presents challenges in evaluation and immediate treatment. The critical concern in managing a dislocation is deciding when a joint can be reduced onsite and when the patient should be splinted and transported for reduction to be performed in the hospital or medical setting. Factors that influence the decision-making process include the following: whether the AT possesses a documented protocol that is supported by his or her supervising physician(s), employer documents, and respective state regulations; the AT's qualifications and experience; the dislocated joint; whether the dislocation is first time or recurrent; the patient's age and general health; and whether associated injuries are present. Recommendations These guidelines are intended to provide considerations for the initial care of specific joint dislocations. They are not intended to represent the standard of care and should not be interpreted as a standard of care for therapeutic or legal discussion.

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annual meeting of the American Academy of Orthopaedic Surgeons, James Garrick and Ralph Requa presented a paper entitled "ACL Injuries in Women: Epidemiology." They found that, between 1965 and the present, 3514 MEDLINE citations were indexed under "anterior cruciate ligament," yet only 130 were indexed under prevention, and fewer than 10 focused on prevention of the injury. This special issue of the Journal of Athletic Training has several purposes: to remind readers that the epidemic of ACL injuries in female athletes continues, to identify potential risk factors that can be targeted for preventive interventions, and to recognize important research initiatives in our quest to reduce the incidence of this injury in both female and male athletes. In 1995, Elizabeth Arendt and Randall Dick published their seminal epidemiologic research in the American Journal of Sports Medicine demonstrating a higher rate of ACL injuries in college female soccer and basketball athletes in comparison with males participating in the same sports. In this issue, you will find a 5-year update of the NCAA epidemiologic research that reaffirms the higher rate of injury in female athletes. You will also find an epidemiologic review that documents a higher rate of ACL injury in physically active females participating at the college, high school, Olympic, and military levels. Both papers emphasize the importance of prevention as the cornerstone to reducing the incidence of ACL injury in the female athlete. To exemplify this emphasis on prevention, many of the articles in this issue focus on the potential risk factors for ACL injury. Extrinsic factors, which are somewhat controllable, include playing style, preparation and practice, conditioning, skill acquisition, environmental conditions, and equipment such as shoes and playing surface. Intrinsic factors include individual physical and psychosocial factors that are less controllable than the extrinsic factors. A plan for the standardized screening of the clinically measurable intrinsic anatomical risk factors, such as subtalar joint pronation, knee recurvatum, external tibial rotation, and lower extremity muscular strength, is presented. Several of the original research papers in this issue focus on the intrinsic risk factors of joint laxity, postural control, and knee biodynamics in female and male subjects. The general use of electromyography in assessing sex differences is explained, and 3 papers examine the neuromuscular factors related to muscle preactivity, fatigue, and reactive muscle firing during functional activity. Very recent research is presented that documents greater anterior laxity in conjunction with elevations in estrogen and progesterone levels during the menstrual cycle. Fluctuating hormonal levels represent one of the more obvious differences between males and females, yet the relevance of this finding to ACL injury in the female athlete has yet to be elucidated. Specialized rehabilitation programs for the female athlete who is ACL deficient or who has undergone ACL re...

Verkorte weergave Balance training for persons with functionally unstable ankles [Journal of Orthopaedic & Sports Physical Therapy 1999;29:478-86] Personen die meerdere keren een inversietrauma van hun enkel hebben ondergaan hebben een enkel die kan worden gekarakteriseerd als functioneel instabiel. Zij hebben de neiging 'door hun enkel te gaan'. Drie factoren waarvan men aanneemt dat ze functionele instabiliteit van het enkelgewricht kunnen veroorzaken zijn anatomische of mechanische instabiliteit, spierzwakte en deficie¨nties in de gewrichtsproprioceptie. Op dit moment zijn er geen objectieve gegevens die afdoend aantonen dat spierzwakte een ree¨le verklaring vormt. De combinatie van mechanische instabiliteit en verminderde neuromusculaire controle als gevolg van deficie¨nties in de gewrichtsproprioceptie lijkt een waarschijnlijker oorzaak.Deficie¨ntie in de proprioceptie van het enkelgewricht met verminderde neuromusculaire controle zijn door meerdere onderzoekers beschreven. Aangetoond is dat mensen die in het verleden meerdere keren een inversietrauma hebben gehad, bij stand op e´e´n been minder goed hun evenwicht kunnen handhaven dan proefpersonen met gezonde enkels. Bovendien is aangetoond dat personen met een instabiele enkel een langere reactietijd vertonen bij plotselinge angulaire verplaatsing dan gezonde controlepersonen. Deze neuromusculaire deficie¨nties, die tot uiting komen in een verminderd evenwichtsvermogen en een toegenomen spier-reactietijd, kunnen iemand gevoelig maken voor herhaalde traumata en verergering van de enkelinstabiliteit.Voor mensen met enkelinstabiliteit worden revalidatieprogramma's aanbevolen die de bestaande neurologische deficie¨nties aanpakken door de gewrichtsproprioceptie te verbeteren. Het gevoel voor gewrichtsbeweging kan mogelijk worden versterkt door een verbeterde functie van de mechanoreceptoren, hetgeen kan leiden tot herstel van de neuromusculaire controle over het gewricht. De geslaagde neuromusculaire terugkoppeling is mogelijk een essentie¨le factor voor een positief resultaat (dat wil zeggen terugkeer tot een stabieler niveau, c.q. het niveau van vo´o´r het trauma).Bij proprioceptieve revalidatieprogramma's wordt veelal gebruikgemaakt van trainingsmiddelen zoals beweegbare evenwichtsplatforms. De effectiviteit van training op zo'n evenwichtsplatform bij niet-aangedane proefpersonen is door diverse onderzoekers nagegaan en gedocumenteerd. Met betrekking tot personen met functionele enkelinstabiliteit moet de effectiviteit van dergelijke programma's echter nog worden aangetoond. Ons onderzoek werd derhalve ontworpen om de effecten op het evenwicht te bepalen van een vier weken durend trainingsprogramma voor e´e´n been bij proefpersonen die zelf aangaven dat zij een instabiele enkel hadden.Met ons onderzoek wilden wij ten eerste mensen met een zelf-aangegeven instabiele enkel vergelijken met proefpersonen met gezonde enkels wat betreft hun vermogen het evenwicht te bewaren op e´e´n been en hun functionele uitkomstscores en ten tweede de effecten kwantificeren...