The Relationship Between Early-Stage Knee Osteoarthritis and Lower-Extremity Alignment, Joint Laxity, and Subjective Scores of Pain, Stiffness, and Function.

CONTEXT: Knee osteoarthritis (OA) is a debilitating disease that affects an estimated 27 million Americans. Changes in lower-extremity alignment and joint laxity have been found to redistribute the medial and/or lateral loads at the joint. However, the effect that changes in anteroposterior knee-joint laxity have on lower-extremity alignment and function in individuals with knee OA remains unclear. OBJECTIVE: To examine anteroposterior knee-joint laxity, lower-extremity alignment, and subjective pain, stiffness, and function scores in individuals with early-stage knee OA and matched controls and to determine if a relationship exists among these measures. DESIGN: Case control. SETTING: Sports-medicine research laboratory. PARTICIPANTS: 18 participants with knee OA and 18 healthy matched controls. INTERVENTION: Participants completed the Western Ontario McMaster (WOMAC) osteoarthritis questionnaire and were tested for total anteroposterior knee-joint laxity (A-P) and knee-joint alignment (ALIGN). MAIN OUTCOME MEASURES: WOMAC scores, A-P (mm), and ALIGN (°). RESULTS: A significant multivariate main effect for group (Wilks' Λ = 0.30, F7,26 = 8.58, P < .0001) was found. Knee-OA participants differed in WOMAC scores (P < .0001) but did not differ from healthy controls on ALIGN (P = .49) or total A-P (P = .66). No significant relationships were identified among main outcome measures. CONCLUSION: These data demonstrate that participants with early-stage knee OA had worse pain, stiffness, and functional outcome scores than the matched controls; however, ALIGN and A-P were no different. There was no association identified among participants' subjective scores, ALIGN, or A-P measures in this study.

Intensity-dependent reductions in resting blood pressure following short-term isometric exercise training.

To reduce resting blood pressure, a minimum isometric exercise training (IET) intensity has been suggested, but this is not known for short-term IET programmes. We therefore compared the effects of moderate- and low-intensity IET programmes on resting blood pressure. Forty normotensive participants (22.3 ± 3.4 years; 69.5 ± 15.5 kg; 170.2 ± 8.7 cm) were randomly assigned to groups of differing training intensities [20%EMGpeak (~23%MVC, maximum voluntary contraction, or 30%EMGpeak (~34%MVC)] or control group; 3 weeks of IET at 30%EMGpeak resulted in significant reductions in resting mean arterial pressure (e.g. -3.9 ± 1.0 mmHg, P < 0.001), whereas 20%EMGpeak did not (-2.3 ± 2.9 mmHg; P > 0.05). Moreover, after pooling all female versus male participants, IET induced a 6.9-mmHg reduction in systolic blood pressure in female participants, but only a 1.5-mmHg reduction in systolic blood pressure in male participants, although the difference was not significant. An IET intensity between 20%EMGpeak and 30%EMGpeak is sufficient to elicit significant resting blood pressure reductions in a short-term training period (3 weeks). In addition, sexual dimorphism may exist in the magnitude of reductions, but further work is required to confirm this possibility, which could be important in understanding the mechanisms responsible.

Reliability of sonographic measurements of the ulnar collateral ligament: a multi-rater prospective study.

Background: The use of sonography is a cost-effective and reliable method to evaluate upper extremity superficial tissue structural integrity and pathology. Establishing the measurement reliability of widely used diagnostic ultrasound evaluation for musculoskeletal assessment is paramount enhance accurate clinical evaluations. The objective of this study was to establish the inter-rater and intra-rater reliability of select ulnar collateral ligament (UCL) thickness measures at two distinct anatomical locations in intercollegiate baseball athletes using ultrasound imaging (USI). Methods: This was a prospective cohort study conducted in a university research laboratory and included a total of 17 NCAA Division I baseball athletes (age 20.4 ± 1.43, height = 183.63 cm ± 6.27 cm, mass = 89.28 kg ± 8.24 kg). Two trained clinicians measured UCL mid-substance and apex thickness in the throwing extremity, prospectively, on 5 occasions at 1-month intervals during rest. Intraclass correlation coefficients (ICCs) (model 3,3), associated standard error of measurement, and 95% minimal detectable change in thickness were derived. Results: Intrarater reliability estimates for operator 1 were 0.90-0.98 (mid-substance) and 0.91-0.99 (apex). Operator 2's values were 0.92-0.97 and 0.93-0.99, respectively. The standard error of measurement (SEM) ranged from 0.045-0.071 cm (mid-substance) and 0.023-0.067 cm (apex). The minimal detectable difference (MDD95) was 0.12-0.20 cm (mid-substance) and 0.07-0.19 cm (apex). Interrater reliability was 0.86-0.96 (mid-substance) and 0.79-0.98 (apex); most ICCs were >0.90. Measurement of UCL thickness at two locations demonstrated very good to excellent reliability with high precision. Using this protocol, two evaluators can obtain consistent UCL measurement at two positions. This finding has significant implications for the clinical evaluation of superficial tissue pathology of the same individual by two experienced practitioners.

Temporal-spatial gait adaptations during stair ascent and descent in patients with knee osteoarthritis.

Knee osteoarthritis (OA) accounts for more functional disability of the lower extremity than any other disease. We recruited 18 patients with knee OA and 18 healthy age-, height-, mass-, and gender-matched control subjects to investigate the effects knee OA has on select spatial and temporal gait variables during a stair climbing task. No group-by-direction interaction was observed; however, significant effects did occur for group and direction. Specifically, patients with knee OA demonstrated less time in single support, greater time in double support, decreased step length, greater step width, less stride length, decreased total gait velocity, greater total time in support, and less total time in swing, compared with controls. Early-stage knee OA directly influences specific temporal and spatial gait characteristics during stair climbing.

Six weeks of balance training improves sensorimotor function in individuals with chronic ankle instability.

STUDY DESIGN: Prospective cohort study. OBJECTIVE: To assess the effect of 6 weeks of balance training on sensorimotor measures previously found to be deficient in participants with chronic ankle instability (CAI). BACKGROUND: CAI is the tendency toward repeated ankle sprains and recurring symptoms, occurring in 40% to 70% of individuals who have previously sustained a lateral ankle sprain. Recent studies have found deficits in sensorimotor measures in individuals with CAI. As balance training is a common component of ankle rehabilitation, understanding its effect on the sensorimotorsystem in individuals with CAI may enable us to optimize protocols to better utilize this rehabilitation method. METHODS: Twelve participants with CAI and 9 healthy volunteers participated. Independent variables were group (CAI, control) and time (pretraining, posttraining). Participants with CAI who completed a 6-week balance training program and healthy controls who did not get any training were pretested and posttested at the beginning and at the end of 6 weeks. RESULTS: The individuals in the CAI group who performed balance training demonstrated better performance than control participants on baseline adjusted posttraining measures of dynamic balance in the anterior medial (P = .021), medial (P = .048), and posterior medial directions (P = .030); motoneuron pool excitability Hmax/Mmax ratio (P = .044) and single-limb presynaptic inhibition (P = .012); and joint position sense inversion variable error (P = .017). It may be of note that no systematic differences were detected for static balance or plantar flexion joint position sense tasks. CONCLUSIONS: After 6 weeks of balance training, individuals with CAI demonstrated enhanced dynamic balance, inversion joint position sense, and changes in motoneuron pool excitability compared to healthy controls who did not train. LEVEL OF EVIDENCE: Therapy, level 2b.

Threshold frequency of an electrically induced cramp increases following a repeated, localized fatiguing exercise.

Though clinical observations and laboratory data provide some support for the neuromuscular imbalance theory of the genesis of exercise-associated muscle cramps, no direct evidence has been published. The purpose of this study was to determine the effect of local muscle fatigue on the threshold frequency of an electrically induced muscle cramp. To determine baseline threshold frequency, a cramp was electrically induced in the flexor hallucis brevis of 16 apparently healthy participants (7 males, 9 females; age 25.1 +/- 4.8 years). The testing order of control and fatigue conditions was counterbalanced. In the control condition, participants rested in a supine position for 30 min followed by another cramp induction to determine post-threshold frequency. In the fatigue condition, participants performed five bouts of great toe curls at 60% one-repetition maximum to failure with 1 min rest between bouts followed immediately by a post-threshold frequency measurement. Repeated-measures analysis of variance and simple main effects testing showed post-fatigue threshold frequency (32.9 +/- 11.7 Hz) was greater (P < 0.001) than pre-fatigue threshold frequency (20.0 +/- 7.7 Hz). An increase in threshold frequency seems to demonstrate a decrease in one's propensity to cramp following the fatigue exercise regimen used. These results contradict the proposed theory that suggests cramp propensity should increase following fatigue. However, differences in laboratory versus clinical fatiguing exercise and contributions from other sources, as well as the notion of a graded response to fatiguing exercise, on exercise-associated muscle cramp and electrically induced muscle cramp should be considered.

A comparison of physiologic and physical discomfort responses between exercise modalities.

To determine differences in physiologic responses and perceived discomfort during maximal and submaximal exercise with 2 common exercise modalities, the elliptical cross-trainer (ECT) and the arc trainer (ARC) were used, which undergoes an excursion of motion using an arc pathway. Eighteen subjects (10 male and 8 female; age = 24.7 +/- 2.6 yr, height = 172.2 +/- 10.3 cm, mass = 69.8 +/- 14.9 kg, %fat = 22.5 +/- 8.1%; mean +/- SD) performed maximal exercise protocols on a treadmill (TML), the ECT, and ARC. Subjects also performed 3 10-minute submaximal exercise bouts on the ECT and ARC at 55%, 65%, and 75% of TML maximal oxygen uptake (VO2max) in which heart rate (HR), VO2, ventilation, respiratory exchange ratio, and hip, knee, and low-back discomfort were monitored. All testing on the ECT and ARC were performed in a counterbalanced order. The VO2max was greater during TML exercise compared with ECT (p = 0.007) but similar to the ARC. Both ECT and ARC elicited lower maximal HR values compared with maximal TML exercise (p = 0.0001). No difference was observed between ECT and ARC for VO2 during the submaximal exercise bouts (p > 0.05). However, HR was greater during submaximal ECT exercise (p < 0.0001). Perception of discomfort was not different between ECT and ARC for knees (p > 0.05) and lower back (p > 0.05) but different for the hips (p = 0.02). Similar VO2max values were observed with ARC and TML modalities. Greater perceptions of discomfort were observed with ECT compared with ARC at similar submaximal exercise intensities, suggesting individuals with, or at risk for, lower-extremity joint pathology may benefit from exercise with modalities other than the ECT.

Segmental spinal reflex adaptations associated with chronic ankle instability.

OBJECTIVE: To further understanding of the role that segmental spinal reflexes play in chronic ankle instability (CAI). DESIGN: A 2 x 2 repeated-measures case-control factorial design. The independent variables were ankle group with 2 levels (healthy, CAI) and stance with 2 levels (single, double legged). SETTING: University research laboratory. PARTICIPANTS: Twenty-two participants with CAI and 21 matched healthy controls volunteered. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The dependent variables were 2 measures of motoneuron pool excitability: paired reflex depression (PRD) and recurrent inhibition. RESULTS: A 2 x 2 repeated-measures multivariate analysis of variance revealed a significant interaction between group and stance on the linear combination of PRD and recurrent inhibition variables (Wilks lambda=.808, F(2,40)=4.77, P=.014). Follow-up univariate F tests revealed an interaction between group and stance on the PRD (F(1,41)=9.74, P=.003). Follow-up dependent t tests revealed a significant difference between single- and double-legged PRD in the healthy participants (t(20)=-3.76, P=.001) with no difference in CAI participants (t(21)=-0.44, P=.67). Finally, there was a significant difference in recurrent inhibition between healthy (mean, 83.66) and CAI (mean, 90.27) (P=.004). CONCLUSIONS: This study revealed that, compared with healthy participants, CAI participants were less able to modulate PRD when going from a double- to a single-legged stance. Additionally, CAI participants showed higher overall levels of recurrent inhibition when compared with healthy matched controls.

Certified athletic trainers' knowledge and perception of professional preparation involving eating disorders among athletes.

The perceived adequacy of professional preparation about eating disorders and disordered eating has not been evaluated in certified athletic trainers (ATCs). This study was intended to establish how ATCs perceive their professional preparation and educational background in identifying and managing eating disorders. A 42-item Web-based survey was specifically created for this study and disseminated to certified 14,477 members of the National Athletic Trainers' Association (NATA), of whom 13.6% (n = 1,966) responded (mean age of respondents, 31.87 +/- 7.82 yrs). The survey consisted of an 11-question demographic section, 13 Likert-scale statements, five "check all that apply" questions, 10 yes/no questions, two "fill in the best answer" questions, and one "check one that applies" question. Statistical analysis focused on qualitative and descriptive analysis of survey items. Our results suggest that ATCs believe that they do not receive enough professional preparation or education in dealing with eating disordered athletes. Despite this finding, they also believe it is their responsibility to identify and deal with eating disordered athletes. The overall findings indicate a need and desire for continuing education about eating disorders.

Effects of ankle support on lower-extremity functional performance: a meta-analysis.

UNLABELLED: Clinicians surmise that the application of external ankle support reduces the ability to perform functional skills and movements, but the outcomes from some of these studies have been inconclusive. PURPOSE: To meta-analyze studies regarding the effects of external ankle support on lower-extremity functional performance measures. METHODS: A total of 93 effects from 17 randomized controlled trials utilizing predominantly crossover designs with recreationally active participants and competitive athletes were subjected to a random-effects meta-analysis. The treatment variable was external ankle support with three levels: adhesive tape, lace-up style, and semirigid style. Differences between mean changes in treatment and control groups were computed as standardized effect sizes for sprint, agility, and vertical jump performance with their 90% confidence intervals (CI). Effect sizes >0.20 were considered substantial. RESULTS: The greatest effect of ankle support on performance was a negative effect of lace-up style brace on sprint speed (effect size -0.22, 90% CI -0.47 to 0.03), equivalent to approximately 1% impairment of speed. The other effects of external ankle support on performance were insubstantial, though most were negative, and their lower confidence limits allowed for realistic chances of impaired performance. Substantial true variation between studies, although poorly defined, was also present for some effects, further increasing the likelihood of performance impairment in some settings. CONCLUSIONS: More research is needed to reduce the uncertainty in the effects of external ankle support on performance. In the meantime, it is our opinion that the benefit in preventing injury outweighs the possibility of substantial but small impairment of performance when athletes use external ankle support.

Exercise and quadriceps muscle cooling time.

CONTEXT: Cryotherapy is commonly used for a variety of purposes; however, the body's response to cryotherapy immediately postexercise is unknown. OBJECTIVE: To investigate the effect of prior exercise on crushed-ice-bag treatment of a large muscle group. DESIGN: 2 x 3 repeated-measures design on depth (1 cm and 2 cm below adipose tissue) and treatment (exercise followed by ice, exercise followed by no ice, and no exercise followed by ice). SETTING: Sports Injury Research Laboratory. PATIENTS OR OTHER PARTICIPANTS: Six physically active, uninjured male volunteers. INTERVENTION(S): For the 2 exercise conditions, subjects rode a stationary cycle ergometer at 70% to 80% of their age-predicted maximum heart rate, as calculated by the Karvonen method. For the no-exercise condition, subjects lay supine on a treatment table. The cryotherapy treatment consisted of a 1-kg ice bag applied to the anterior mid thigh. For the no-ice condition, subjects lay supine on a treatment table. MAIN OUTCOME MEASURE(S): Time required for the intramuscular temperatures at the 1-cm and 2-cm depths below adipose tissue to return to pre-exercise baseline and time required to cool the 1-cm and 2-cm depths to 10 degrees C below the pre-exercise temperature. RESULTS: The time to cool the rectus femoris to the pre-exercise temperature using a crushed-ice-bag treatment was reduced by approximately 40 minutes (P < .001). The ice bag cooled the 1-cm and 2-cm depths to the pre-exercise temperature within 7 minutes (P = .38), but the 2-cm tissue depth took nearly 13.5 minutes longer to cool than the 1-cm depth when no ice was applied (P = .001). The 1-cm depth cooled to 10 degrees C below the pre-exercise temperature about 8 minutes sooner than the 2-cm depth, regardless of whether the tissue was exercised or not (P < .001). Exercise shortened the cooling time to 10 degrees C below the pre-exercise temperature by approximately 13 minutes (P = .05). CONCLUSIONS: Exercise before cooling with a crushed-ice bag enhanced the removal of intramuscular heat.

Local ice-bag application and triceps surae muscle temperature during treadmill walking.

CONTEXT: Ice bags "to go" are a common practice in athletic training. OBJECTIVE: To determine the effect of submaximal exercise on tissue temperatures during a common ice-bag application. DESIGN: 2 X 5 fully repeated-measures design with treatment (cooling while resting, cooling while walking) and time (pretreatment, immediately after ice application, and at 10, 20, and 30 minutes during treatment) as the independent variables. SETTING: Laboratory setting. PATIENTS OR OTHER PARTICIPANTS: Sixteen healthy, physically active volunteers (age = 21.63 +/- 2.63 yrs, height = 68.97 +/- 4.00 cm, mass = 80.97 +/- 18.18 kg, calf skinfold = 21.1 +/- 9.3 mm). MAIN OUTCOME MEASURE(S): Left triceps surae intramuscular and skin temperatures, as measured by thermocouples to the nearest 0.1 degrees C, served as dependent measures. INTERVENTION(S): After collecting baseline temperatures, we secured a 1.0-kg ice bag to the calf using plastic wrap before the subject either rested prone or walked on a treadmill at 4.5 km/h for 30 minutes. RESULTS: Treatment did not (P < 0.10) affect the approximately 15 degrees C (P < 0.0001) surface temperature decrease, which remained depressed immediately upon ice-bag application (P < 0.05). Conversely, intramuscular temperature continually cooled (34 to 28 degrees C), while subjects rested (P < 0.0001), whereas no change took place during walking (P = 0.49). Moreover, at the 20- and 30-minute treatment intervals, the resting intramuscular temperatures were, respectively, 3.9 degrees C and 5.4 degrees C cooler than the walking intramuscular temperatures (P < 0.01). CONCLUSIONS: The current trend of wrapping "to go" ice bags to the leg is not likely to achieve deep tissue cooling despite surface temperature decreases.

A comparison of intramuscular temperatures during ultrasound treatments with coupling gel or gel pads.

STUDY DESIGN: A repeated-measures design was used. The independent variable was ultrasound coupling medium with 2 levels: gel pad and traditional gel. The dependent variable was peak intramuscular (IM) tissue temperature. OBJECTIVE: To compare changes in IM temperature during similar ultrasound treatments with 2 different coupling media. BACKGROUND: Gel pads are gaining popularity as an ultrasound coupling medium. Intramuscular temperatures during ultrasound with gel pads and standard gel have not been compared. METHODS AND MEASURES: Subjects were 13 student volunteers (21.3 +/- 1.4 years of age) without lower-extremity pathology. Ultrasound treatments were administered in a laboratory on two separate occasions 48 hours apart, each with a different coupling medium (standard ultrasound gel or gel pad). One-MHz continuous ultrasound was administered for 7 minutes at 1.5 W/cm2 with the transducer head moving 3 to 4 cm/s over an area approximately twice the size of the transducer head. Tissue temperature was measured every 10 seconds using implantable thermocouples inserted at a 3-cm depth to the surface of the right medial calf. Data were analyzed using an ANCOVA with pretreatment temperature as the covariate. RESULTS: Tissue temperatures increased during both treatments, with the mean and standard deviation peak temperature during the gel pad treatment reaching 39.40 +/- 1.5 degrees C compared to 39.20 +/- 2.4 degrees C during the normal gel treatment. Statistical analysis revealed no difference in temperature between ultrasound treatments using gel and those performed using gel pads. CONCLUSIONS: Because temperature changes were similar with both treatments, we conclude that these coupling methods are equivalent under the ultrasound application parameters tested.

Application of statistics in establishing diagnostic certainty.

The examination and assessment of injured and ill patients leads to the establishment of a diagnosis. However, the tests and procedures used in health care, including procedures performed by certified athletic trainers, are individually and collectively imperfect in confirming or ruling out a condition of concern. Thus, research into the utility of diagnostic tests is needed to identify the procedures that are most helpful and to indicate the confidence one should place in the results of the test. The purpose of this report is to provide an overview of selected statistical procedures and the interpretation of data appropriate for assessing the utility of diagnostic tests with dichotomous (positive or negative) outcomes, with particular attention to the interpretation of sensitivity and specificity estimates and the reporting of confidence intervals around likelihood ratio estimates.

Three-dimensional joint kinematics of ACL-deficient and ACL-reconstructed knees during stair ascent and descent.

Mechanical environmental changes in the knee are induced by altered joint kinematics under cyclic loading during activities of daily living after anterior cruciate ligament (ACL) injury. This is considered a risk factor in progressive cartilage degeneration and the early onset of osteoarthritis following ACL injury and even after reconstructive surgery. The purpose of this study was to examine 3D joint kinematics of ACL-deficient and ACL-reconstructed knees to health controls during stair ascent and descent. A 3D optical video motion capture system was used to record coordinate data from reflective markers positioned on subjects as they ascended and descended a custom-built staircase. Spatiotemporal gait and knee joint kinematic variables were calculated and further analyzed. The ACL-deficient knees exhibited a significant extension deficit compared to the ACL-intact controls. A more varus and internally rotated tibial position was also identified in the ACL-deficient knees during both stair ascent and descent. The ACL-reconstructed knees exhibited less abnormality in both spatiotemporal gait parameters and joint kinematics, but these variables were not fully restored to a normal level. The kinematic profiles of the ACL-reconstructed knees were more similar to those of the ACL-deficient knees when compared to the ACL-intact knees. This suggests that the ACL-reconstructed knees had been "under-corrected" rather than "over-corrected" by the reconstructive surgery procedure. Findings from this study may provide more insight with respect to improving ACL reconstruction surgical techniques, which may aid the early progression of cartilage degeneration in ACL-reconstructed knees.

Lower extremity joint kinematics during stair climbing in knee osteoarthritis.

PURPOSE: Knee osteoarthritis (OA) is one of the most prevalent chronic lower extremity diseases, causing profound limitation of movement and ability to perform activities of daily living. The purpose of this study was to compare various hip, knee, and ankle joint kinematic variables between knee OA subjects and matched healthy controls during stair ascent and descent. METHODS: Eighteen subjects with knee OA (age = 60.2 ± 9.9 yr, mass = 90.3 ± 16.7 kg, height = 168.4 ± 9.9 cm) and 18 healthy matched controls (age = 60.3 ± 10.7 yr, mass = 81.1 ± 21.2 kg, height = 168.3 ± 11.9 cm) participated in the study. Subjects performed five ascending and descending trials on a custom-built staircase while their motion was captured three-dimensionally using an eight-camera optical video motion capture system. RESULTS: Significant group × direction interactions were found for average hip flexion angle at foot strike (P = 0.04), for average ankle adduction angle at foot strike (P = 0.01), and for peak ankle dorsiflexion angle during support (P = 0.05) and swing (P = 0.01). Specifically, knee OA and control subjects demonstrated greater hip flexion angle at foot strike and ankle dorsiflexion angle during swing but showed smaller ankle dorsiflexion angle during support during stair ascent compared with descent. Furthermore, compared with controls, knee OA patients demonstrated greater hip abduction at foot strike (-3.1° ± 3.9°) and smaller peak knee flexion during support (60.4° ± 5.0°) and swing (86.7° ± 5.4°). Time of peak hip abduction (34.2% ± 7.1%), hip flexion (7.0% ± 12.3%), knee flexion (69.8% ± 4.6%), dorsiflexion (51.4% ± 2.9%), and ankle adduction (37.3% ± 20.8%) during support occurred later in the gait cycle for knee OA patients. CONCLUSIONS: These data demonstrate that knee OA directly influences specific knee joint kinematics and induces kinematic alterations at the hip and ankle perhaps to compensate for the existing knee joint pathology.

Mechanical joint laxity associated with chronic ankle instability: a systematic review.

CONTEXT: Lateral ankle sprains can manifest into chronic mechanical joint laxity when not treated effectively. Joint laxity is often measured through the use of manual stress tests, stress radiography, and instrumented ankle arthrometers. PURPOSE: To systematically review the literature to establish the influence of chronic ankle instability (CAI) on sagittal and frontal plane mechanical joint laxity. DATA SOURCES: Articles were searched with MEDLINE (1966 to October 2008), CINAHL (1982 to October 2008), and the Cochrane Database of Systematic Reviews (to October 2008) using the key words chronic ankle instability and joint laxity, functional ankle instability and joint laxity, and lateral ankle sprains and joint laxity. STUDY SELECTION: To be included, studies had to employ a case control design; mechanical joint laxity had to be measured via a stress roentogram, an instrumented ankle arthrometer, or ankle/foot stress-testing device; anteroposterior inversion or eversion ankle-subtalar joint complex laxity had to be measured; and means and standard deviations of CAI and control groups had to be provided. DATA EXTRACTION: One investigator assessed each study based on the criteria to ensure its suitability for analysis. The initial search yielded 1378 potentially relevant articles, from which 8 were used in the final analysis. Once the study was accepted for inclusion, its quality was assessed with the PEDro scale. DATA SYNTHESIS: Twenty-one standardized effect sizes and their 95% confidence intervals were computed for each group and dependent variable. CAI produced the largest effect on inversion joint laxity; 45% of the effects ranged from 0.84 to 2.61. Anterior joint laxity measures were influenced second most by CAI (effects, 0.32 to 1.82). CAI had similar but less influence on posterior joint laxity (effects, -0.06 to 0.68) and eversion joint laxity (effects, 0.03 to 0.69). CONCLUSION: CAI has the largest effect with the most variability on anterior and inversion joint laxity measurements, consistent with the primary mechanism of initial injury.

Influence of external ankle support on lower extremity joint mechanics during drop landings.

OBJECTIVE: To investigate the effects of external ankle support (EAS) on lower extremity joint mechanics and vertical ground-reaction forces (VGRF) during drop landings. DESIGN: A 1 x 3 repeated-measures, crossover design. SETTING: Biomechanics research laboratory. PATIENTS: 13 male recreationally active basketball players (age 22.3 +/- 2.2 y, height 177.5 +/- 7.5 cm, mass 72.2 +/- 11.4 kg) free from lower extremity pathology for the 12 mo before the study. INTERVENTIONS: Subjects performed a 1-legged drop landing from a standardized height under 3 different ankle-support conditions. MAIN OUTCOME MEASURES: Hip, knee, and ankle angular displacement along with specific temporal (TGRFz1, TGRFz2; s) and spatial (GRFz1, GRFz2; body-weight units [BW]) characteristics of the VGRF vector were measured during a drop landing. RESULTS: The tape condition (1.08 +/- 0.09 BW) demonstrated less GRFz1 than the control (1.28 +/- 0.16 BW) and semirigid conditions (1.28 +/- 0.21 BW; P < .0001), and GRFz2 was unaffected. For TGRFz1, no-support displayed slower time (0.017 +/- 0.004 s) than the semirigid (0.014 +/- 0.001 s) and tape conditions (0.014 +/- 0.002 s; P < .05). For TGRFz2, no-support displayed slower time (0.054 +/- 0.006 s) than the semirigid (0.050 +/- 0.006 s) and tape conditions (0.045 +/- 0.004 s; P < .05). Semirigid bracing was slower than the tape condition, as well (P < .05). Ankle-joint displacement was less in the tape (34.6 degrees +/- 7.7 degrees) and semirigid (36.8 degrees +/- 9.3 degrees) conditions than in no-support (45.7 degrees +/- 7.3 degrees; P < .05). Knee-joint displacement was larger in the no-support (45.1 degrees +/- 9.0 degrees) than in the semirigid (42.6 degrees +/- 6.8 degrees; P < .05) condition. Tape support (43.8 degrees +/- 8.7 degrees) did not differ from the semirigid condition (P > .05). Hip angular displacement was not affected by EAS (F(2,24) = 1.47, P = .25). CONCLUSIONS: EAS reduces ankle- and knee-joint displacement, which appear to influence the spatial and temporal characteristics of GRFz1 during drop landings.

Cryotherapy and ankle bracing effects on peroneus longus response during sudden inversion.

Cryotherapy and ankle bracing are often used in conjunction as a treatment for ankle injury. No studies have evaluated the combined effect of these treatments on reflex responses during inversion perturbation. This study examined the combined influence of ankle bracing and joint cooling on peroneus longus (PL) muscle response during ankle inversion. A 2x2 RM factorial design guided this study; the independent variables were: ankle brace condition (lace-up brace, control), and treatment (ice, control), and the dependent variables studied were PL stretch reflex latency (ms), and PL stretch reflex amplitude (% of max). Twenty-four healthy participants completed 5 trials of a sudden inversion perturbation to the ankle/foot complex under each ankle brace and cryotherapy treatment condition. No two-way interaction was observed between ankle brace and treatment conditions on PL latency (P=0.283) and amplitude (P=0.884). The ankle brace condition did not differ from control on PL latency and amplitude. Cooling the ankle joint did not alter PL latency or amplitude compared to the no-ice treatment. Ankle bracing combined with joint cooling does not have a deleterious effect on dynamic ankle joint stabilization during an inversion perturbation in normal subjects.

Contributing factors to medial tibial stress syndrome: a prospective investigation.

PURPOSE: To conduct a prospective, multisite, cohort study investigating the possible risk factors for medial tibial stress syndrome (MTSS) in college athletes. METHODS: One hundred and forty-six healthy, collegiate athletes from NCAA Division I and Division II institutions participated in the study. Subjects first completed a health history questionnaire to establish previous history of injury and underwent a physical examination to assess their ankle/foot strength, ankle/foot range of motion, tibial varum, and navicular drop before the start of their respective athletic season. Athletes were instructed to report to a certified athletic trainer if they developed pain on their tibia. If MTSS was present, subjects were then placed into the symptomatic group. Independent t-tests and chi-square analyses were used to determine whether differences existed between MTSS and healthy athletes for the continuous and the discrete dependent variables, respectively. The significant dependent variables were then used in the discriminant function analysis. RESULTS: Twenty-nine subjects developed MTSS during this study. Athletes that had been participating in athletic activity for fewer than 5 yr were significantly more likely to develop MTSS (P = 0.002). Additionally, athletes with a previous history of MTSS (P = 0.0001), a previous history of stress fracture (P = 0.039), and the use of orthotics (P = 0.031) were more likely to develop MTSS compared with those who did not develop MTSS. CONCLUSION: This study established that the factors most influencing MTSS development were previous history of MTSS and stress fracture, years of running experience, and orthotic use. These data demonstrate the importance of establishing a thorough history before the start of the season so that athletes who might be at risk for MTSS development can be identified.