Effects of PNF and Static Stretching on Architecture and Viscoelastic Properties of Hemiplegic Elbow

The Comparison of the Effects of PNF and Static Stretching Applied to the Elbow Flexors on Muscle Architecture and Viscoelastic Properties In Individuals With Chronic Stroke

The patients who were diagnosed with stroke in governmental/university/private hospitals, and who needed rehabilitation because of the increased flexor tone in the elbow joint, decreased range of motion and/or decreased function of the upper extremity will be invited to the study in accordance with the criteria that are given in inclusion and exclusion part. Participants will be randomly assigned to one of two parallel groups, either the PNF Stretching Group (n=17) or the Prolonged Stretching Group (n=17), according to the order of participation in the study by simple randomization. An online computer program will be used to assign participants (https://www.randomizer.org/). Exercises that will increase proximal stabilization and control will be applied to both groups for 4 weeks, 5 days a week. In addition to the exercises, prolonged stretches for 10 minutes will be applied to the Prolonged Stretching Group, and PNF stretching will be applied to the PNF Stretching Group. At the beginning and the end of the study, muscle architecture, muscular viscoelastic properties, range of motion, proprioception, upper extremity motor performance and function and posture will be evaluated.

Flexion synergy is common in the upper extremities of patients with hemiplegia after a stroke, and the elbow is involuntarily held in the flexion posture with the effect of increased flexor tone in the elbow. Over time, weakness in the hemiparetic arm, motor disturbances caused by abnormal synergies, and persistent spasticity begin to cause secondary changes in the musculoskeletal system that may limit the use of the arm and affect functional mobility; soft tissue shortening and contracture formations can be seen. Studies show that static stretching can lead to a significant change in the number of sarcomeres. However, considering the nature of spasticity, which is one of the most common complications in stroke patients, stretching should be done slowly and for a long time. This may lead to an increase in the time spent by patients in the clinic. At the same time, since it can be painful for some patients, it can increase spasticity rather than reduce it. In addition, hand contact is not frequent during prolonged stretches, which has proven to increase the positive effects of rehabilitation, and may result in a decrease in the maximum impact that will occur during rehabilitation.

There is positive evidence that Proprioceptive Neuromuscular Facilitation (PNF) stretching, another stretching method, reduces both muscle and muscle-tendon unit tension more than static stretching in healthy individuals and can lead to a more effective lengthening of muscle fascicles compared to static stretching. In addition, it does not contain the adverse effects of static stretching because it requires hand contact and is applied with active contraction of the patient. Considering this situation, we hypothesized that PNF stretching, which will be used in stroke rehabilitation, may be an ideal rehabilitation method for optimizing muscle fascicle length as well as inhibiting elbow flexion posture by providing tone regulation and thus reducing stiffness in the muscles. Sample size calculation was done by GPower 3.1. A total of 34 hemiplegic patients will be invited to the study and divided into 2 groups.

Inclusion Criteria:

• Stroke diagnosed by magnetic resonance imaging or computed tomography, regardless of ischemic or hemorrhagic origin;
• Hemiplegia caused only by stroke;
• At least 3 months have passed since the diagnosis of stroke;
• At least 1+ spasticity according to Modified Ashworth Scale in the elbow flexors of the affected side;
• Ability to maintain sitting balance for at least 20 seconds without support;
• Being older than 18 years old;
• Being voluntary to participate in the study.

Exclusion Criteria:

• Having a history of multiple strokes or bilateral involvement;
• Botox application to any/all of the Biceps, Brachialis or Brachioradialis muscles within the last 6 months;
• Changes in pharmacological treatment in the last 6 months;
• Muscle involvement on the affected side that completely prevents the elbow joint range of motion;
• Presence of conditions that may affect the level of spasticity (infection, febrile illness, etc.)
• Mini Mental State Assessment Test score below 24;
• Presence of neurological diagnosis other than stroke;
• Insufficient vision, hearing and/or understanding ability to administer assessments and treatments.