Context: Rolling sensations at the ankle are common after injury and represent failure in neural regulation of joint stiffness. However, deficits after ankle injury are variable and strategies for optimizing stiffness may differ across patients.
Objective: To determine if ankle stiffness and muscle activation differ between patients with varying history of ankle injury.
Patients: Fifty-nine individuals were stratified into healthy (CON, n = 20), functionally unstable (UNS, n = 19), and coper (COP, n = 20) groups.
Main Outcome Measures: A 20° supination perturbation was applied to the ankle as position and torque were synchronized with activity of tibialis anterior, peroneus longus, and soleus. Subjects were tested with muscles relaxed, while maintaining 30% muscle activation, and while directed to react and resist the perturbation.
Results: No group differences existed for joint stiffness (F = 0.07, P = .993); however, the UNS group had higher soleus and less tibialis anterior activation than the CON group during passive trials (P < .05). In addition, greater early tibialis anterior activation generally predicted higher stiffness in the CON group (P ≤ .03), but greater soleus activity improved stiffness in the UNS group (P = .03).
Conclusion: Although previous injury does not affect the ability to stiffen the joint under laboratory conditions, strategies appear to differ. Generally, the COP has decreased muscle activation, whereas the UNS uses greater plantar-flexor activity. The results of this study suggest that clinicians should emphasize correct preparatory muscle activation to improve joint stiffness in injury-rehabilitation efforts.
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http://dx.doi.org/10.1123/jsr.2015-0061 | DOI Listing |
J Am Chem Soc
January 2025
Key Laboratory for Advanced Materials, Feringa Nobel Prize Scientist Joint Research Center, Frontiers Science Center for Materiobiology and Dynamic Chemistry, Institute of Fine Chemicals, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237, P. R. China.
Understanding and effectively controlling molecular conformational changes are essential for developing responsive and dynamic molecular systems. Here, we report that an oriented external electric field (OEEF) is an effective catalyst for the cis-trans isomerization of stiff-stilbene, a key component of overcrowded alkene-based rotary motors. This reversible isomerization occurs under ambient conditions, is free from side reactions, and has been verified using ultraperformance liquid chromatography and UV-vis absorption spectroscopy.
View Article and Find Full Text PDFJ Dance Med Sci
January 2025
Frontier Research Institute of Convergence Sports Science, College of Educational Sciences, Yonsei University, Seoul, Korea.
Ballet-based dance training emphasizes the equal development of both legs. However, dancers often perceive differences between their legs during balance or landing. There still needs to be more consensus on the functional difference between dominant (D) and non-dominant legs (ND).
View Article and Find Full Text PDFMaterials (Basel)
December 2024
Doctoral School of the Rzeszow University of Technology, Rzeszow University of Technology, Al. Powstańców Warszawy 12, 35-959 Rzeszów, Poland.
This article presents a new parametric method for shaping flat transverse frame structural systems supporting thin-walled roofs made of flat sheets folded unidirectionally and transformed elastically to various shell forms. The parameterization was limited to one independent variable, that is the stiffness of the support joints. For different discrete values of simulated stiffness, the surface areas of the cross sections of the tensile and compressed elements and the section modulus of the bending elements were calculated so as to obtain the optimized work of the frame and its elements in the assumed load environment.
View Article and Find Full Text PDFJ Orthop Surg Res
January 2025
Center for Rehabilitation Research, School of Allied Health Sciences, Texas Tech University Health Sciences Center, Lubbock, TX, USA.
Background: The sacroiliac joints (SIJ) are specialized articulations in the pelvis that allow load transfer between the upper and lower body. Traumatic pelvic disruption often requires surgical fixation of at least one of these joints. Subsequent SIJ pain is associated with asymmetries in joint laxity or stiffness.
View Article and Find Full Text PDFBMC Musculoskelet Disord
January 2025
Department of Orthopedics, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, 100045, China.
Background: Displaced tibial tubercle (TT) fractures in adolescents are typically treated with open reduction and internal fixation. While metallic screw (MS) fixation provides strong stability, it often results in a high incidence of postoperative screw head protrusion or irritation, leading to additional removal surgery. Bioabsorbable screw (BS) fixation presents an alternative that may avoid these issues, though its stability has not yet been extensively documented in the literature.
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