This study aims

1. To examine the reliability of SWE assessment in the shoulder muscles of persons after a stroke.
2. To assess if differentiation can be made between the hemiplegic (HP) and non-hemiplegic (NHP) side and between stroke patients and matched healthy volunteers (discriminative validity).
3. To assess if an immediate effect on the pectoralis major and minor can be measured after applying transversal stretch technique to the pectoralis major muscles (response validity).

Stroke patients will be assessed on 2 days with an interval of 3 days (Friday - Monday).

Day 1 (Friday): shear wave velocity (SWV) will be assessed by 2 assessors in randomised order. Each assessor will evaluate SWV of 6 shoulder muscles (m. supraspinatus, m. infraspinatus, m. rhomboid major, m. deltoideus, m. pectoralis major, m. pectoralis minor).

At the end of the assessment secondary outcome measures will be assessed.

Day 2 (Monday): SWV will be reassessed by assessor 1 to measure test-retest reliability.

Position of the patient will be changed. SWV of the pectoralis major and minor muscle will be reassessed.

Assessor 2 will perform a transversal stretch of the m. pectoralis major or a passive mobilisation of the hand at the hemiplegic arm of the stroke patients. Assessor 1 will reassess the SWV of the pectoralis major and minor muscle to assess if there is an immediate effect of the intervention. Assessor 1 will be blinded for the intervention.

Healthy controls (matched for age, gender and BMI):

Only one test day to assess SWV of 6 shoulder muscles. Secondary outcome measures will be assessed after SWE assessment.

Stroke group

Inclusion:

• Stroke patients in the subacute phase after stroke (< 6 months post stroke)
• Able to sit independently with support of the back, but without support of the arms
• With upper-limb (UL) impairment: i.e. no maximum score (36) on the shoulder elbow part of the Fugl-Meyer UL (FM UL)

Exclusion Criteria:

• Other neurologic disorders
• Shoulder or neck surgery before stroke onset
• Arthroscopic surgery in the last year before stroke onset.
• Shoulder or neck pain in the last year before stroke onset.
• Severe cognitive or language deficits that inhibit the participants of understanding simple commands or providing valuable information regarding the outcome measures - measured with the Ability Q.
• Participants who are not able to maintain the test position.
• Pregnancy

Healthy controls can participate if they

• Have not suffered a stroke or other neurological disorders
• Did not have surgery at the shoulder and/or neck
• Did not have arthroscopic surgery in the last year before stroke
• If they do not suffer any shoulder or neck pain