PAIN SENSITIVITY IN CHRONIC ACHILLES TENDINOPATHY.

Background: Achilles tendinopathy is a common overuse injury sustained by athletes (including runners) that often becomes chronic. There is evidence that chronic musculoskeletal pain conditions exhibit signs of nervous system sensitization.

Hypothesis/purpose: The objective of this study was to compare pain sensitivity (pressure pain threshold [PPT], heat pain threshold [HPT], and heat temporal summation [HTS]) between active healthy adults with and without chronic Achilles tendinopathy in order to determine if signs of peripheral and/or central sensitization exist in chronic Achilles tendinopathy.

The effect of experimental shoulder pain on contralateral muscle force and activation.

Inhibition of rotator cuff activation and force after local experimental pain has been previously shown. Clinically, strength is often indexed to the uninvolved side in order to quantify deficits during injury and recovery. This study assessed the effect of experimental subacromial pain on contralateral shoulder external rotation (ER) force and activation.

Peripheral Nociception Is Associated with Voluntary Activation Deficits and Quadriceps Weakness Following Total Knee Arthroplasty.

Background: Quadriceps weakness is a hallmark of total knee arthroplasty and is driven by reduced voluntary muscle activation following the surgical procedure. The mechanisms underlying postoperative activation deficits are not well established, although nociception has been implicated via both spinal reflex and supraspinal pathways. The purpose of this study was to assess the role of nociception in postoperative recovery of strength and activation.

Reliability and precision of single frequency bioelectrical impedance assessment of lower extremity swelling following total knee arthroplasty.

Total knee arthroplasty (TKA) is the most common elective orthopedic surgery performed in the United States. Following surgery patients experience significant lower extremity swelling that is related to poor satisfaction with surgery and is hypothesized to contribute to functional decline. However, in practice, precise and reliable methods for measuring lower extremity swelling do not exist.

Effects of Noxious Electrical Stimulation and Eccentric Exercise on Pain Sensitivity in Asymptomatic Individuals.

Background: Achilles tendinopathy is a common overuse injury in running and jumping athletes. Currently, we do not understand why some conservative interventions (eg, noxious electrical stimulation and eccentric training) may reduce the pain associated with tendinopathy.

Objective: To determine whether noxious electrical stimulation (NES) or eccentric contractions would alter pain sensitivity around the asymptomatic Achilles tendon.

IMPROVED PRESSURE PAIN THRESHOLDS AND FUNCTION FOLLOWING NOXIOUS ELECTRICAL STIMULATION ON A RUNNER WITH CHRONIC ACHILLES TENDINOPATHY: A CASE REPORT.

Background And Purpose: Achilles tendinopathy is a common overuse injury sustained by athletes including runners. The use of noxious electrical stimulation for the treatment of chronic tendinopathies is a novel treatment intervention, which may alter pain perception and serve as adjunct technique in the recovery of painfree function. The purpose of this case report is to demonstrate the use of noxious electrical stimulation for the treatment of chronic, bilateral Achilles tendinopathy that was resistant to conservative treatment using plantarflexor eccentric exercise.

Forelimb locomotor rating scale for behavioral assessment of recovery after unilateral cervical spinal cord injury in rats.

Background: Cervical spinal cord injury (SCI) models in rats have become increasingly useful because of their translational potential. The goal of this study was to design, develop and validate a quick and reliable forelimb locomotor rating scale for adult rats with unilateral cervical SCI injury.

New Method: Adult female rats were subjected to a C5 unilateral mild contusion (n=10), moderate contusion (n=10) or hemisection injury (n=9).

Experimental pain inhibits infraspinatus activation during isometric external rotation.

Background: The effect of pain on muscle activation is poorly understood. This study examined the effects of acute experimental pain on rotator cuff muscle force and voluntary activation (VA). We hypothesized that acute subacromial pain would cause inhibition of infraspinatus VA with a corresponding decrease in external rotation force.

Amphetamine-enhanced motor training after cervical contusion injury.

Individually, motor training, pharmacological interventions, and housing animals in an enriched environment (EE) following spinal cord injury (SCI) result in limited functional improvement but, when combined, may enhance motor function. Here, we tested amphetamine (AMPH)-enhanced skilled motor training following a unilateral C3-C4 contusion injury on the qualitative components of reaching and on skilled forelimb function, as assessed using single-pellet and staircase reaching tasks. Kinematic analysis evaluated the quality of the reach, and unskilled locomotor function was also tested.

Voluntary activation of the infraspinatus muscle in nonfatigued and fatigued states.

Hypothesis: Failure of voluntary activation is an important source of weakness in several different muscles after injury or surgery. Despite the high prevalence of shoulder rotator cuff disorders and associated weakness, no test currently exists to identify voluntary activation deficits for the rotator cuff. The purpose of this study was to develop a test to quantify voluntary activation of the infraspinatus.

Effect of cervical dorsolateral funiculotomy on reach-to-grasp function in the rat.

Cervical spinal cord injury (SCI) can severely impair reaching and grasping ability, and several descending systems, including the rubrospinal tract and corticospinal tract, have been implicated in the control of reach-to-grasp movements. The primary aim of this study was to characterize further the forelimb deficits associated with a cervical dorsolateral funiculotomy, which ablates the rubrospinal tract but spares the dorsal and ventral corticospinal tract in the rat. Adult female rats that preferred to use their right forelimb to reach for single pellets received a lesion to the right cervical dorsolateral funiculus between the C3-4 dorsal roots.

Neuromuscular electrical stimulation versus volitional isometric strength training in children with spastic diplegic cerebral palsy: a preliminary study.

Background: To date, no reports have investigated neuromuscular electrical stimulation (NMES) to increase muscle force production of children with cerebral palsy (CP) using high-force contractions and low repetitions.

Objective: The aims of this study were to determine if isometric NMES or volitional training in children with CP could increase muscle strength and walking speed and to examine the mechanisms that may contribute to increased force production.

Methods: Eleven children with spastic diplegia were assigned to an NMES training group or to a volitional training group.

Voluntary muscle activation, contractile properties, and fatigability in children with and without cerebral palsy.

Cerebral palsy (CP) may lead to profound weakness in affected portions of the extremities and trunk. Knowing the mechanisms underlying muscle weakness will help to better design interventions for increasing force production in children with CP. This study quantified voluntary muscle activation, contractile properties, and fatigability of the quadriceps femoris and triceps surae in children with and without CP.

Are voluntary muscle activation deficits in older adults meaningful?

The relationship between the central activation ratio (CAR) and contraction force is curvilinear, not linear as was previously believed. Voluntary quadriceps femoris muscle activation from previously collected data sets in 46 older adults (64-84 years) and 46 young adults (18-32 years) were therefore reexamined using a curvilinear model of the voluntary muscle activation-percent maximum voluntary force relationship. This method revealed lower voluntary muscle activation in older adults (0.

Predictability of maximum voluntary isometric knee extension force from submaximal contractions in older adults.

The purposes of this study were to develop and test a model describing the relationship between the central activation ratio (CAR; a measure of voluntary muscle activation) and percent maximum voluntary contraction (%MVC) force for old adults and to provide a method for more accurate determination of voluntary muscle activation failure. Twenty-one adults (ages 64-81) performed isometric testing of the quadriceps at 25%, 50%, 75%, and 100% MVC. During each contraction, a 100-HZ, 120-ms train of electrical pulses was delivered to the quadriceps muscle to quantify voluntary muscle activation.