The influence of age on spinal muscle activation patterns and its relation to kinematics is poorly understood. We aimed at understanding age-related changes to spine and trunk muscle activity in addition to spinal and lower limb kinematics during treadmill walking under various conditions. An observational study was conducted evaluating asymptomatic young (n = 10; 3F, 7M; 26.3±2.5yrs) and older (n = 9; 3F, 6M; 67.1±4.2yrs) adults’ treadmill walking at 2km/h and 4km/h, each at 0, 1, 5, and 10% inclination. Unilateral (right side) electromyography (EMG) was recorded from deep and superficial multifidus (intramuscular) and erector spinae and abdominal obliques (surface); trunk and leg kinematics were also measured. Muscle activity was characterised by peak amplitude and duration of activity, and the time-point of peak amplitude in the gait cycle (0–100%). Peak activation in older adults was lower for the superficial multifidus (p<0.0001) and higher for the thoracolumbar (p<0.001) and lumbar erector spinae (p<0.01). The duration of activation was longer in older adults for all muscles (p<0.05) except the superficial multifidus, and longer during faster walking for all participants. The time-point of peak amplitude in the gait cycle was earlier in older participants for the external obliques (p<0.05). Walking speed appeared to influence muscle activity more than inclination. Older adults used less spine, trunk and lower limb motion, except at the ankle. Age-related differences within multifidus and between paravertebral and trunk muscles were inconsistent. Walking at 4km/h at 5–10% inclination may specifically target the lumbar paravertebral muscles.

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). Publications on SWE‐based comparisons of muscle stiffness between individuals with and without musculoskeletal pain are increasing rapidly. This work reviewed and mapped the existing evidence regarding objectively measured muscle stiffness in musculoskeletal pain conditions and surveyed current methods of applying SWE to measure muscle stiffness.Methods: A systematic search was conducted in PubMed and CINAHL using the keywords “muscle stiffness”, “shear wave elastography”, “pain”, “asymptomatic controls” and synonyms. The search was supplemented by a hand search using Google Scholar. Included articles were critically appraised with the AXIS tool, supplemented by items related to SWE methods. Results were visually mapped and narratively described.Results: Thirty of 137 identified articles were included. High‐quality evidence was missing. The results comprise studies reporting lower stiffness in symptomatic participants, no differences between groups and higher stiffness in symptomatic individuals. Results differed between pain conditions and muscles, and also between studies that examined the same muscle(s) and pathology. The methods of the application of SWE were inconsistent and the reporting was often incomplete.Conclusions: Existing evidence regarding the objective stiffness of muscles in musculoskeletal pain conditions is conflicting. Methodological differences may explain most of the inconsistencies between findings. Methodological standards for SWE measurements of muscles are urgently required.

Zusammenfassung Fast jeder kennt „verspannte“ Muskulatur, aber was sind physiologisch betrachtet Muskelverspannungen? Aktivierte Muskeln, die nicht entspannen können? Steifere oder härtere Muskeln? In der vorliegenden Arbeit wird aktuelle wissenschaftliche Evidenz zur Aktivität und Steifigkeit verspannter Nackenmuskeln präsentiert und die dabei angewandten Messmethoden werden mit ihren Limitationen vorgestellt. Diese Limitationen verdeutlichen die Begrenztheit des aktuellen Stands wissenschaftlicher Erkenntnisse und den weiteren Forschungsbedarf. Abschließend wird ein aktuelles drittmittelgefördertes Forschungsprojekt zur Messung von Muskelverspannungen vorgestellt.

Everyone has or will have experienced some degree of neck pain. Typically, neck pain is associated with the sensation of tense, tight, or stiff neck muscles. However, it is unclear whether the neck muscles are objectively stiffer with neck pain. This study used 1099 ultrasound elastography images (elastograms) obtained from 38 adult women, 20 with chronic neck pain and 18 asymptomatic. For training machine learning algorithms, 28 numerical characteristics were extracted from both the original and transformed shear wave velocity color-coded images as well as from respective image segments. Overall, a total number of 323 distinct features were generated from the data. A supervised binary classification was performed, using six machine-learning algorithms. The random forest algorithm produced the most accurate model to distinguish the elastograms of women with chronic neck pain from asymptomatic women with an AUC of 0.898. When evaluating features that can be used as biomarkers for muscle dysfunction in neck pain, the region of the deepest neck muscles (M. multifidus) provided the most features to support the correct classification of elastograms. By constructing summary images and associated Hotelling’s T² maps, we enabled the visualization of group differences and their statistical confirmation.

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. The shear modulus at different functional tasks served as a reference for normalizing the neck muscles’ shear modulus of 38 women, 20 with chronic neck pain and 18 asymptomatic. Reference tasks were maximal voluntary contraction, relaxed sitting, prone head lift, balancing 1 kg on the head, and neck extension at 48 N. The effects of normalization on within-group variation and between-group differences were compared. Normalization with maximal voluntary contraction was discarded due to imaging problems. Normalization with relaxed sitting, prone head lift, balancing 1 kg, and neck extension at 48 N reduced within-group variation, by 23.2%, 26.8%, 11.6%, and 33.6%, respectively. All four normalization approaches reduced the p-values when testing for between-group differences. For the pain group, normalization with relaxed sitting and head lift indicated less normalized muscle stiffness, while normalization with balancing 1 kg and extension at 48 N indicated higher stiffness. The contradictory results are explainable by non-significant group differences in the reference tasks. Normalization of the muscle shear modulus is effective to reduce within-group variation, but a trustworthy normalization approach for group comparisons has yet to be identified.

Lieber Jochen, vielen Dank für das Anstoßen einer Diskussion zu unserem Beitrag. Betriebliche Gesundheitsförderung (BGF) und Prävention sind effektiv. Effektivität wird im betrieblichen Bereich, in dem der Arbeitgeber in Gesundheitsförderung investiert, zuerst ökonomisch ausgedrückt. Der iga.Report 28 zu „Wirksamkeit und Nutzen arbeitsweltbezogener Gesundheitsförderung und Prävention, Zusammenstellung der wissenschaftlichen Evidenz “ bezifferte den durchschnittlichen Return-on-Investment auf 2,7 [1], was im iga.Report 40, der den Zeitraum 2012 bis 2018 umfasst, bestätigt wurde [2]. Es scheint sich also zu lohnen, genau dort tätig zu werden, wo die Probleme auftreten. Braucht es dafür Physiotherapeut*innen? Ja, AUCH Physiotherapeut*innen, neben anderen Expert*innen. Bewegungsexpertise UND ein biopsychosoziales Verständnis von Gesundheit sind wichtig. Ich stimme Dir zu, dass es keine Physiotherapeut*innen braucht, um die Umsetzung von DIN-Normen zu prüfen. Im Gegenteil könnte dies sogar einen Konflikt mit den betriebsinternen Beauftragten für Arbeitssicherheit auslösen. Aber, um belastende und zumeist repetitive Arbeit weitergehend zu beurteilen, soziale und andere Stressfaktoren in die Beurteilung muskuloskelettaler Belastungen einzubeziehen, ist m. E. die physiotherapeutische Kompetenz der Haltungs- und Bewegungsanalyse, der individuellen Beratung und Lösungserarbeitung wertvoll. Gerade unser Fokus auf Dynamik ergänzt die meist statischen Beschreibungen der DIN-Normen. Hierbei geht es nicht darum, dass wir per se besser wüssten, wie eine Arbeitsanforderung motorisch zu bewältigen sei. Es geht häufig um kleine Verhaltensänderungen, wie z. B. etwas mehr Gehen im Arbeitsalltag, etwas vielfältigere körperliche Aktivität, kleine Umstrukturierungen von Arbeitsprozessen, gemeinsame Lösungserarbeitung mit Betroffenen im Rahmen vorgegebener Bedingungen, Änderungsmöglichkeiten und Motivationen. Auch Empfehlungen für Bedingungsveränderungen (Verhältnisprävention) können angezeigt sein, z. B. unterstützt die Evidenz den Gebrauch von Sitz-Steh-Tischen, der die tägliche Sitzzeit um durchschnittlich 100 Minuten verringert [3]. Wenn wir jedoch als Physiotherapeut*innen in einem anderen als dem therapeutischen Sektor tätig werden, sollten wir den Aufbau des Sektors, die anderen im Team und die Struktur des Settings, in dem wir uns bei dieser Tätigkeit befinden, sowie die dort üblichen Fachtermini kennen, um uns professionell dort einordnen zu können. Unser Artikel ist daher als einführende Vorstellung des betrieblichen Arbeitssektors gedacht. Abschließend und ergänzend zu unserem Artikel möchte ich aus der Arbeit von Pieper et al. aus dem Jahr 2015 einige evidenzbasierte Empfehlungen zitieren [4]: Mit freundlichen Grüßen Dr. Angela Dieterich Article published online: 07 December 2022 © 2022. Thieme. All rights reserved. Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany