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Murray, UT, United States

Look N.,University of Colorado at Boulder | Arellano C.J.,University of Colorado at Boulder | Grabowski A.M.,University of Colorado at Boulder | McDermott W.J.,The Orthopedic Specialty Hospital | And 3 more authors.
Chaos | Year: 2013

In this paper, we study dynamic stability during running, focusing on the effects of speed, and the use of a leg prosthesis. We compute and compare the maximal Lyapunov exponents of kinematic time-series data from subjects with and without unilateral transtibial amputations running at a wide range of speeds. We find that the dynamics of the affected leg with the running-specific prosthesis are less stable than the dynamics of the unaffected leg and also less stable than the biological legs of the non-amputee runners. Surprisingly, we find that the center-of-mass dynamics of runners with two intact biological legs are slightly less stable than those of runners with amputations. Our results suggest that while leg asymmetries may be associated with instability, runners may compensate for this effect by increased control of their center-of-mass dynamics. © 2013 AIP Publishing LLC. Source


Barker T.,The Orthopedic Specialty Hospital | Traber M.G.,Oregon State University
Journal of Evidence-Based Complementary and Alternative Medicine | Year: 2011

Muscular (quadriceps) weakness is a predominant impairment that follows anterior cruciate ligament injury and surgery. This continued weakness impairs activities of daily living and could predispose patients to adverse conditions later in life, such as knee osteoarthritis. Vitamins E and C have potent antioxidant and anti-inflammatory activity. Herein, the authors summarize the state-of-the science and suggest directions for future research endeavors regarding the therapeutic influence of vitamins E and C, or other antioxidants, on the recovery from anterior cruciate ligament injury and surgery. © The Author(s) 2011. Source


Barker T.,The Orthopedic Specialty Hospital | Henriksen V.T.,The Orthopedic Specialty Hospital | Martins T.B.,Arup | Hill H.R.,Arup | And 7 more authors.
Nutrients | Year: 2013

The primary purpose of this study was to identify if serum 25-hydroxyvitamin D (25(OH)D) concentrations predict muscular weakness after intense exercise. We hypothesized that pre-exercise serum 25(OH)D concentrations inversely predict exercise-induced muscular weakness. Fourteen recreationally active adults participated in this study. Each subject had one leg randomly assigned as a control. The other leg performed an intense exercise protocol. Single-leg peak isometric force and blood 25(OH)D, aspartate and alanine aminotransferases, albumin, interferon (IFN)-γ, and interleukin-4 were measured prior to and following intense exercise. Following exercise, serum 25(OH)D concentrations increased (p < 0.05) immediately, but within minutes, subsequently decreased (p < 0.05). Circulating albumin increases predicted (p < 0.005) serum 25(OH)D increases, while IFN-γ increases predicted (p < 0.001) serum 25(OH)D decreases. Muscular weakness persisted within the exercise leg (p < 0.05) and compared to the control leg (p < 0.05) after the exercise protocol. Serum 25(OH)D concentrations inversely predicted (p < 0.05) muscular weakness (i.e., control leg vs. exercise leg peak isometric force) immediately and days (i.e., 48-h and 72-h) after exercise, suggesting the attenuation of exercise-induced muscular weakness with increasing serum 25(OH)D prior to exercise. Based on these data, we conclude that pre-exercise serum 25(OH)D concentrations could influence the recovery of skeletal muscle strength after an acute bout of intense exercise. © 2013 by the authors; licensee MDPI, Basel, Switzerland. Source


Murphy C.A.,The Orthopedic Specialty Hospital | McDermott W.J.,The Orthopedic Specialty Hospital | Petersen R.K.,The Orthopedic Specialty Hospital | Johnson S.E.,UNITED ORTHOPEDIC GROUP | Baxter S.A.,The Orthopedic Specialty Hospital
Journal of Shoulder and Elbow Surgery | Year: 2013

Background: Numerous rehabilitation protocols exist for postoperative rotator cuff repairs. Because the goal of early rehabilitation is to prevent postoperative adhesions while protecting the repaired tendons, it would be advantageous to know which range-of-motion exercises allow the rotator cuff to remain the most passive in a painful, guarded, postsurgical shoulder. Methods: Twenty-six subjects who had undergone subacromial decompression, distal clavicle resection, or a combination of both procedures volunteered to participate within the first 4 days after surgery. Fine-wire electrodes were inserted into the subject's supraspinatus (SS) and infraspinatus (IS). Muscle activity was recorded at resting baseline (BL) and during 14 exercises that have been found in the passive phase of rotator cuff protocols and tested in healthy subjects. Each exercise was compared with BL activity as well as with other exercises in the same movement group. Results: The SS remained as passive as BL during therapist- and self-assisted external rotation, therapist-assisted elevation, pendulums, and isometric internal rotation and adduction. The IS was activated greater than BL for all 14 exercises studied. Conclusion: Of the 14 exercises studied, 6 allowed the SS and 0 allowed the IS to remain as passive as quiet-stance BL in postsurgical subacromial decompression/distal clavicle resection patients. © 2013 Journal of Shoulder and Elbow Surgery Board of Trustees. Source


Christensen J.C.,The Orthopedic Specialty Hospital | Goldfine L.R.,The Orthopedic Specialty Hospital | West H.S.,The Orthopedic Specialty Hospital
Journal of Sport Rehabilitation | Year: 2013

Study Design: Prospective randomized clinical trial. Methods and Measures: Thirty-six patients who had a primary anterior cruciate ligament reconstruction (ACL-R) with a semitendinosus-gracilis (STG) autograft from a single orthopedic surgeon were prospectively randomized into 2 groups. Nineteen patients were randomized to the aggressive group (53% male, mean age 30.1 + 10.5 y) and 17 to the nonaggressive group (88% male, mean age 33.1 + 10.9 y). Impairment measures of anteroposterior (A-P) knee laxity, range of motion (ROM), and peak isometric force (PIF) values were obtained 12 wk postoperatively. Subjective response to the International Knee Documentation Committee knee form (IKDC) was collected 1, 12, and 24 wk postoperatively. One-way ANOVA was used to analyze differences between groups at 12 wk for A-P knee laxity, ROM, and PIF. Differences between the groups for the IKDC scores were determined using 1-way ANOVA with repeated measures 1, 12, and 24 wk postoperatively. Bonferroni adjustment was used for multiple comparisons. Results: There were no differences between the groups for the baseline characteristics (P > .05). There was no difference found between the groups in respect to A-P knee laxity, ROM, or PIF at 12 wk (P > .05). Further analysis also showed no significant differences in the IKDC scores between groups at 12 or 24 wk (P > .05). Conclusions: No differences were found between early aggressive and nonaggressive rehabilitation after an isolated ACL-R using STG autografts for the primary outcomes of A-P knee laxity and subjective IKDC score. In addition, no differences were observed for secondary outcomes between groups for differences in ROM and PIF values. © 2013 Human Kinetics, Inc. Source

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