title: Dynamic "Range of Motion" Hindlimb Stretching Disrupts Locomotor Function in Rats with Moderate Subacute Spinal Cord Injuries.
abstract: Joint contractures and spasticity are two common secondary complications of a severe spinal cord injury (SCI), which can significantly reduce quality of life, and stretching is one of the top strategies for rehabilitation of these complications. We have previously shown that a daily static stretching protocol administered to rats at either acute or chronic time points after a moderate or moderate-severe T10 SCI significantly disrupts their hindlimb locomotor function. The objective of the current study was to examine the effects of dynamic range of motion (ROM) stretching on the locomotor function of rats with SCI as an alternative to static stretching. Starting at 6 weeks post-injury (T10 moderate contusion) eight adult Sprague-Dawley rats were subjected to hindlimb stretching for 4 weeks. Our standard stretching protocol (six maneuvers to stretch the major hindlimb muscle groups) was modified from 1 min static stretch-and-hold at the end ROM of each stretch position to a dynamic 2 sec hold, 1 sec release rhythm repeated for a duration of 1 min. Four weeks of daily (5 days/week) dynamic stretching led to significant disruption of locomotor function as assessed by the Basso, Beattie, Bresnahan (BBB) Open Field Locomotor Scale and three-dimensional (3D) kinematic and gait analyses. In addition, we identified and analyzed an apparently novel hindlimb response to dynamic stretch that resembles human clonus. The results of the current study extend the observation of the stretching phenomenon to a new modality of stretching that is also commonly used in SCI rehabilitation. Although mechanisms and clinical relevance still need to be established, our findings continue to raise concerns that stretching as a therapy can potentially hinder aspects of locomotor recovery.
authors.affiliation: 1 Department of Physiology, University of Louisville , Louisville, Kentucky.|2 Kentucky Spinal Cord Injury Research Center, University of Louisville , Louisville, Kentucky.
authors.forename: Anastasia
authors.initials: A
authors.lastname: Keller
authors.affiliation: 3 J.B. Speed School of Engineering, Department of Bioengineering, University of Louisville , Louisville, Kentucky.
authors.forename: Kathlene
authors.initials: K
authors.lastname: Rees
authors.affiliation: 2 Kentucky Spinal Cord Injury Research Center, University of Louisville , Louisville, Kentucky.|4 Department of Neurological Surgery, University of Louisville , Louisville, Kentucky.
authors.forename: Daniella
authors.initials: D
authors.lastname: Prince
authors.affiliation: 2 Kentucky Spinal Cord Injury Research Center, University of Louisville , Louisville, Kentucky.|4 Department of Neurological Surgery, University of Louisville , Louisville, Kentucky.
authors.forename: Johnny
authors.initials: J
authors.lastname: Morehouse
authors.affiliation: 2 Kentucky Spinal Cord Injury Research Center, University of Louisville , Louisville, Kentucky.|4 Department of Neurological Surgery, University of Louisville , Louisville, Kentucky.
authors.forename: Alice
authors.initials: A
authors.lastname: Shum-Siu
authors.affiliation: 2 Kentucky Spinal Cord Injury Research Center, University of Louisville , Louisville, Kentucky.|4 Department of Neurological Surgery, University of Louisville , Louisville, Kentucky.
authors.forename: David
authors.initials: D
authors.lastname: Magnuson
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D006614:Hindlimb / Q000503:physiopathology*; D008124:Locomotion / Q000502:physiology*; D052580:Muscle Stretching Exercises / Q000009:adverse effects*; D016059:Range of Motion, Articular / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013119:Spinal Cord Injuries / Q000503:physiopathology* / Q000534:rehabilitation
keywords: SCI; dynamic stretching; locomotor function; physical therapy; rehabilitation