Is musculoskeletal pain associated with increased muscle stiffness? Evidence map and critical appraisal of muscle measurements using shear wave elastography.

Introduction And Aims: Approximately 21% of the world's population suffers from musculoskeletal conditions, often associated with sensations of stiff muscles. Targeted therapy requires knowing whether typically involved muscles are objectively stiffer compared to asymptomatic individuals. Muscle stiffness is quantified using ultrasound shear wave elastography (SWE).

Assessment of Neck Muscle Shear Modulus Normalization in Women with and without Chronic Neck Pain.

Identifying the objective stiffness of the neck muscles facilitates the early and specific diagnosis of neck pain and targeted therapy. However, individual variation in the muscle shear modulus obscures differences between healthy and diseased individuals. Normalization may improve the comparability between individuals.

[On the move-Prevention of chronic pain with physical activity and movement].

Background: Sufficient physical activity and exercise shows a variety of health-promoting positive effects. In the context of pain therapy, promotion of physical activity could be an important contribution to primary, secondary and tertiary prevention of chronic pain.

Objectives: The aim is to investigate the relationship between physical activity and chronic pain, the preventive effect of physical activity on pain and the factors to successfully promote physical activity in people with chronic pain.

Neck Muscle Stiffness Measured With Shear Wave Elastography in Women With Chronic Nonspecific Neck Pain.

Objective: Utilizing shear wave elastography, we compared the stiffness of the neck extensor muscles and the stiffness in muscle-specific regions between women with chronic nonspecific neck pain and asymptomatic controls.

Design: Cross-sectional observational study.

Methods: We measured the average muscle stiffness over multiple neck extensor muscles and in regions corresponding approximately to the trapezius, splenius capitis, semispinalis capitis, semispinalis cervicis, and multifidus muscles using ultrasound shear wave elastography in 20 women with chronic nonspecific neck pain and 18 asymptomatic women during multiple tasks.

Spatial variation and inconsistency between estimates of onset of muscle activation from EMG and ultrasound.

Delayed onset of muscle activation can be a descriptor of impaired motor control. Activation onset can be estimated from electromyography (EMG)-registered muscle excitation and from ultrasound-registered muscle motion, which enables non-invasive measurements in deep muscles. However, in voluntary activation, EMG- and ultrasound-detected activation onsets may not correspond.

Shear wave elastography reveals different degrees of passive and active stiffness of the neck extensor muscles.

Purpose: The neck extensor muscles contribute to spinal support and posture while performing head and neck motion. Muscle stiffness relates to passive elasticity (support) and active tensioning (posture and movement) of muscle. It was hypothesized that support and motion requirements are reflected in the distribution of stiffness between superficial and deep neck extensor muscles.

M-Mode Ultrasound Reveals Earlier Gluteus Minimus Activity in Individuals With Chronic Hip Pain During a Step-down Task.

Study Design: Controlled laboratory study.

Background: The hip abductor muscles are important hip joint stabilizers. Hip joint pain may alter muscle recruitment.

M-mode ultrasound used to detect the onset of deep muscle activity.

M-mode ultrasound imaging (US) reflects motion of connective tissue within muscles. As muscle contraction is accompanied by motion of muscle tissue, M-mode US may be used to measure non-invasively the onset of deep muscle activity. Isometric hip abduction was measured on nine healthy subjects in the deep region of the gluteus medius muscle and in gluteus minimus by fine-wire electromyography (EMG) and M-mode US.

Muscle thickness measurements to estimate gluteus medius and minimus activity levels.

The clinical assessment of gluteus medius and minimus force sharing requires non-invasive measurements of individual activity levels. Do ultrasound measurements of change of muscle thickness substitute invasive electromyography (EMG)? Isometric hip abduction in 20-80% maximal voluntary isometric contraction (MVIC) was measured using dynamometry, M-mode ultrasound for gluteus medius and minimus thickness and EMG using (1) surface electrodes on gluteus medius, n = 15, (2) fine-wire electrodes in deep gluteus medius and minimus, n = 6. Gluteus medius thickened by 5.

Separate assessment of gluteus medius and minimus: B-mode or M-mode ultrasound?

The hip abductors gluteus medius (Gmed) and minimus (Gmin) differ slightly in function and how they are affected by hip joint pathology. A separate assessment of Gmed and Gmin is feasible by ultrasound (US) imaging. B-mode and M-mode US can be used to measure muscle thickness.