Sasha Gorrell and Drew A. Anderson
, & Carter, 2010 ; Sundgot-Borgen & Torstveit, 2004 ). Runners may be at increased risk for ED pathology due to certain psychosocial factors, including compulsive exercise ( Meyer, Taranis, Goodwin, & Haycraft, 2011 ). Some work has conceptualized compulsive exercise as ‘obligatory,’ with links to ED
Andrea Cripps and Scott C. Livingston
A cerebral concussion is a traumatically induced transient disturbance of brain function characterized by a complex pathophysiologic process and is classified as a subset of mild traumatic brain injury. The occurrence of intracranial lesions after sport-related head injury is relatively uncommon, but the possibility of serious intracranial injury (ICI) should be included in the differential diagnosis. ICIs are potentially life threatening and necessitate urgent medical management; therefore, prompt recognition and evaluation are critical to proper medical management. One of the primary objectives of the initial evaluation is to determine if the concussed athlete has an acute traumatic ICI. Athletic trainers must be able promptly recognize clinical signs and symptoms that will enable them to accurately differentiate between a concussion (ie, a closed head injury not associated with significant ICI) and an ICI. The identification of predictors of intracranial lesions is, however, relatively broad.
Focused Clinical Question:
Which clinical examination findings (ie, clinical signs and symptoms) indicate possible intracranial pathology in individuals with acute closed head injuries?
Shelby J. Martin and Timothy Anderson
Athletes represent a high-risk population for eating pathology (EP) and eating disorders. Indeed, compared to the 0.9–3.5% prevalence rate of eating disorders in the general population ( Americal Psychological Association [APA], 2013 ), the prevalence of DSM-diagnosed eating disorders in athletes
Michael J. Axe, Katherine Linsay and Lynn Snyder-Mackler
The purpose of this study was to determine whether there was a relationship between knee hyperextension and intra-articular pathology in 100 consecutive patients whose sole ligament injury was an arthroscopically confirmed anterior cruciate ligament (ACL) rupture. Hyperextension of both knees was measured using a supine heel-height measurement of high reliability. There was more articular damage to the total joint, lateral joint, and lateral meniscus in patients who hyperextended than in those who did not. There was more articular damage to the total joint and medial joint in patients who were chronically ACL deficient than in those who were acutely or subacutely ACL deficient. The results demonstrate that individuals with ACL injuries whose knees hyperextend 3 cm or more sustain significantly more joint damage at the time of injury than in those whose knees hyperextend less than 3 cm. This study further defines the role of knee hyperextension in ACL injuries and offers a useful and reliable means of measuring knee hyperextension.
Esther Suter, Walter Herzog and Robert Bray
This study assessed muscle inhibition in patients with chronic anterior cruciate ligament (ACL) deficiency or ACL reconstruction. A series of protocols were tested for their effectiveness in increasing activity of the individual knee extensor muscles and decreasing muscle inhibition of the whole quadriceps group. Quadriceps muscle inhibition was measured by superimposing an electrical twitch onto the quadriceps muscle during a maximal voluntary knee extension. The level of activation of the individual knee extensor and knee flexor muscles was assessed via electromyography (EMG). Patients with ACL pathologies showed strength deficits and muscle inhibition in the knee extensors of the involved leg and the contralateral leg. Muscle inhibition was statistically significantly greater in ACL-deficient patients compared to ACL-reconstructed patients. When a knee extension was performed in combination with a hip extension, there was a significant increase, p < 0.05, in activation of the vastus medialis and vastus lateralis muscles compared to isolated knee extension. The use of an anti-shear device, designed to help stabilize the ACL-deficient knee, resulted in increased inhibition in the quadriceps muscle. Furthermore, a relatively more complete activation of the vasti compared to the rectus femoris was achieved during a fatiguing isometric contraction. Based on the results of this study, it is concluded that performing knee extension in combination with hip extension, or performing fatiguing knee extensor contractions, may be more effective in fully activating the vasti muscles than an isolated knee extensor contraction. Training interventions are needed to establish whether these exercise protocols are more effective than traditional rehabilitation approaches in decreasing muscle inhibition and achieving better functional recovery, including equal muscle strength in the injured and the contralateral leg.
Conrad M. Gabler, Adam S. Lepley, Tim L. Uhl and Carl G. Mattacola
Proper neuromuscular activation of the quadriceps muscle is essential for maintaining quadriceps (quad) strength and lower-extremity function. Quad activation (QA) failure is a common characteristic observed in patients with knee pathologies, defined as an inability to voluntarily activate the entire alpha-motor-neuron pool innervating the quad. One of the more popular techniques used to assess QA is the superimposed burst (SIB) technique, a force-based technique that uses a supramaximal, percutaneous electrical stimulation to activate all of the motor units in the quad during a maximal, voluntary isometric contraction. Central activation ratio (CAR) is the formula used to calculate QA level (CAR = voluntary force/SIB force) with the SIB technique. People who can voluntarily activate 95% or more (CAR = 0.95–1.0) of their motor units are defined as being fully activated. Therapeutic exercises aimed at improving quad strength in patients with knee pathologies are limited in their effectiveness due to a failure to fully activate the muscle. Within the past decade, several disinhibitory interventions have been introduced to treat QA failure in patients with knee pathologies. Transcutaneous electrical nerve stimulation (TENS) and cryotherapy are sensory-targeted modalities traditionally used to treat pain, but they have been shown to be 2 of the most successful treatments for increasing QA levels in patients with QA failure. Both modalities are hypothesized to positively affect voluntary QA by disinhibiting the motor-neuron pool of the quad. In essence, these modalities provide excitatory afferent stimuli to the spinal cord, which thereby overrides the inhibitory afferent signaling that arises from the involved joint. However, it remains unknown whether 1 is more effective than the other for restoring QA levels in patients with knee pathologies. By knowing the capabilities of each disinhibitory modality, clinicians can tailor treatments based on the rehabilitation goals of their patients.
Focused Clinical Question:
Is TENS or cryotherapy the more effective disinhibitory modality for treating QA failure (quantified via CAR) in patients with knee pathologies?
Column-editor : Robert I. Moss
Paul D. Loprinzi
Examine the association between objectively-measured moderate-to-vigorous physical activity (MVPA) and engagement in self-reported muscle strengthening activities (MSA) with alanine aminotransferase (ALT) and gamma-glutamyltransferase (GGT), and in turn, how each of these parameters associate with of all-cause mortality.
Data from the 2003–2006 NHANES were employed, with follow-up through December 31, 2011 (N = 5030; 20+ yrs). Physical activity was assessed via accelerometry; MSA was assessed via survey; and ALT and GGT were assessed via a blood sample. Linear regression and Cox proportional hazard models were used.
MVPA (βadjusted = 0.15; 95% CI: –0.45 to 0.76; P = .60) was not associated with ALT, but MSA was (β adjusted = –0.31; 95% CI: –0.56 to –0.05; P = .02). With regard to GGT, MSA was not significant (β adjusted = –0.12; 95% CI: –0.71 to 0.47; P = .67), nor was MVPA (β adjusted = –1.10; 95% CI: –2.20 to 0.06; P = .06). Higher ALT levels were associated with increased allcause mortality risk (HRadjusted = 1.05; 95% CI: 1.02 to 1.06; P < .001).
Physical activity is favorably associated with markers of hepatic inflammation, and higher levels of markers of hepatic inflammation are associated with increased mortality risk. These findings suggest that physical activity may help protect against premature mortality through its influence on liver pathology.