Investigating musculoskeletal tissue stiffness and its response to exercise

Ley, Cameron D. ORCID: 0009-0000-0238-216X (2025). Investigating musculoskeletal tissue stiffness and its response to exercise. University of Birmingham. Ph.D.

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Abstract

The aim of this thesis is to investigate the non-invasive estimation of musculoskeletal (MSK) tissue stiffness to develop understanding of its mechanical properties and to determine the efficacy of doing so in an elite sport setting. The following objectives were set to achieve this aim and based on the gaps identified in the literature: to investigate (1) the validity of the MyotonPRO as a method of estimating muscle stiffness, (2) the reliability of shear wave elastography (SWE) in assessing MSK tissue stiffness, (3) the occurrence of tissue- and region- specific differences in MSK tissue stiffness, and (4) the impact of exercise interventions on acute changes in MSK tissue stiffness. To achieve these objectives and gain this novel knowledge, this thesis contains five distinct phases: the exploratory phase (Chapters 1 and 2); the methodological phase (Chapters 3 and 4); the mechanistic phase (Chapter 5); the experimental phase (Chapter 6); and the synthesis phase (Chapter 7).

The exploratory phase involved an introduction to the topic and sets out the objectives of the thesis (Chapter 1), and a narrative review outlining the importance of understanding muscle stiffness and the methods of measuring it; and evaluating the broad literature surrounding the applications of SWE as a method of estimating muscle stiffness in the clinical and athletic settings (Chapter 2). The methodological phase involved assessing the validity of the MyotonPRO as a method of estimating MSK tissue stiffness compared with SWE (Chapter 3), and assessing the reliability of SWE for estimating the stiffness of rectus femoris (RF) muscle and overlying skin and fascial tissue (Chapter 4). The mechanistic phase involved the use of SWE to determine tissue- and region-specific differences in RF muscle and fascial tissue stiffness (Chapter 5). The experimental phase involved a randomised crossover intervention study to assess the impact of real-world training interventions on MSK tissue stiffness and examine the relationship between MSK tissue stiffness and joint range of motion/flexibility (Chapter 6). Finally, the synthesis phase discusses the findings of the thesis, placing them in the context of the existing literature and providing practical recommendations for the measurement of muscle stiffness applied in the clinical and athletic settings, as well as describing the future directions of research in the field (Chapter 7).

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):