Doublet stimulation protocol to minimize musculoskeletal stress during paralyzed quadriceps muscle testing

Shauna Dudley-Javoroski; Andrew E Littmann; Masaki Iguchi; Richard K Shields

doi:10.1152/japplphysiol.00892.2007

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Doublet stimulation protocol to minimize musculoskeletal stress during paralyzed quadriceps muscle testing

Journal article

Open access

Peer reviewed

Doublet stimulation protocol to minimize musculoskeletal stress during paralyzed quadriceps muscle testing

Shauna Dudley-Javoroski, Andrew E Littmann, Masaki Iguchi and Richard K Shields

Journal of applied physiology (1985), Vol.104(6), pp.1574-1582

06/2008

DOI: 10.1152/japplphysiol.00892.2007

PMCID: PMC2744492

PMID: 18436697

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https://www.ncbi.nlm.nih.gov/pmc/articles/2744492View

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Abstract

With long-term electrical stimulation training, paralyzed muscle can serve as an effective load delivery agent for the skeletal system. Muscle adaptations to training, however, will almost certainly outstrip bone adaptations, exposing participants in training protocols to an elevated risk for fracture. Assessing the physiological properties of the chronically paralyzed quadriceps may transmit unacceptably high shear forces to the osteoporotic distal femur. We devised a two-pulse doublet strategy to measure quadriceps physiological properties while minimizing the peak muscle force. The purposes of the study were 1) to determine the repeatability of the doublet stimulation protocol, and 2) to compare this protocol among individuals with and without spinal cord injury (SCI). Eight individuals with SCI and four individuals without SCI underwent testing. The doublet force-frequency relationship shifted to the left after SCI, likely reflecting enhancements in the twitch-to-tetanus ratio known to exist in paralyzed muscle. Posttetanic potentiation occurred to a greater degree in subjects with SCI (20%) than in non-SCI subjects (7%). Potentiation of contractile rate occurred in both subject groups (14% and 23% for SCI and non-SCI, respectively). Normalized contractile speed (rate of force rise, rate of force fall) reflected well-known adaptations of paralyzed muscle toward a fast fatigable muscle. The doublet stimulation strategy provided repeatable and sensitive measurements of muscle force and speed properties that revealed meaningful differences between subjects with and without SCI. Doublet stimulation may offer a unique way to test muscle physiological parameters of the quadriceps in subjects with uncertain musculoskeletal integrity.

Adaptation, Physiological

Femoral Fractures - etiology

Electric Stimulation - adverse effects

Reproducibility of Results

Torque

Spinal Cord Injuries - complications

Humans

Middle Aged

Stress, Mechanical

Male

Quadriceps Muscle - physiopathology

Exercise Test - adverse effects

Muscle Contraction

Exercise Test - methods

Femoral Fractures - prevention & control

Paralysis - physiopathology

Adult

Female

Spinal Cord Injuries - physiopathology

Femoral Fractures - physiopathology

Muscle Strength

Paralysis - etiology

Details

Title: Subtitle: Doublet stimulation protocol to minimize musculoskeletal stress during paralyzed quadriceps muscle testing
Creators: Shauna Dudley-Javoroski - The Univ. of Iowa, Iowa City, IA 52242, USA
Andrew E Littmann
Masaki Iguchi
Richard K Shields
Resource Type: Journal article
Publication Details: Journal of applied physiology (1985), Vol.104(6), pp.1574-1582
DOI: 10.1152/japplphysiol.00892.2007
PMID: 18436697
PMCID: PMC2744492
NLM abbreviation: J Appl Physiol (1985)
ISSN: 8750-7587
eISSN: 1522-1601
Publisher: United States
Grant note: R01-NR010285-05 / NINR NIH HHS R01 NR010285 / NINR NIH HHS R01 NR010285-05 / NINR NIH HHS
Language: English
Date published: 06/2008
Academic Unit: Orthopedics and Rehabilitation; Physical Therapy and Rehabilitation Science
Record Identifier: 9984046820502771

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