Dr Isobel Jacob

Background and Purpose Tensiomyography (TMG) is reported to measure muscle contractile properties of superficial skeletal muscle. Between day reliability has not been reported for all of the major lower limb muscles in a mixed gender sample of healthy adults. Therefore, the aim of this study was to examine the between-day reliability of muscle contractile properties associated with involuntary contractions of the rectus femoris (RF) and bicep femoris (BF), as measured by TMG. Study Design Within-subject repeated measures study (3 consecutive days) Methods Twenty-four healthy participants (twelve male; twelve females) were recruited to take part in the study over 3 consecutive days. Measurements of muscle contractile properties were obtained on the bicep femoris (BF) and rectus femoris (RF) muscles in the dominant limb. All data were checked for normality using the Shapiro-Wilk test. Pooled intra-class correlation coefficient (ICC), coefficient of variance (CV) and standard error of measurement (SEM) values were generated for the BF and RF for delay time (Td), sustain time (Ts), relaxation time (Tr), contraction time (Tc) maximal displacement (Dm). Additionally, a Bland-Altman analysis was performed for paired data points (day 1 vs 2, 2 vs 3 and 3 vs 1). Identical analyses were then performed on gender sub-groups. Results Good to excellent ICC values (0.68-0.93) were reported for delay time (Td), contraction time (Tc), and maximal displacement (Dm) in BF and RF muscles. Conversely, relaxation time (Tr) and sustain time (Ts) reported low ICC values (-0.10-0.56). Levels of agreement were not significantly different in most pairs of data points across the whole sample and also across males and females (p=>0.05). However, significant differences were detected in the whole sample: day 3 vs day 1 in the Td (p=0.03) and Dm RF (p=0.009); males: BF Td day 1 vs 2 (p=0.04); females: BF day 2 vs 2 (p=0.01), RF Td day 1 vs 2 (p=0.03), RF Ts day 3 vs 1 (p=0.04). Conclusion The Td, Tc, and Dm variables obtained during TMG measurements demonstrate acceptable reliability across 3 consecutive days. The Tr and Ts variables cannot be measured reliably between days using TMG.

OBJECTIVE: Upper leg skeletal or lean tissue mass, strength and muscle quality have emerged as time-sensitive indices of muscular health. The aim of this study was to generate a comparative data set based on these indices, in healthy young (n=30, 29.0 ± 3.0 y old) and older (n=32, 58.7 ± 2.8 y old) adults, in order to evaluate their construct validity in establishing cut-points for muscle health. APPROACH: Whole body and upper leg lean tissue mass was obtained (iDXATM; GE Healthcare, Madison, WI) prior to the assessment of maximal voluntary isometric torque of the knee extensors and flexors (Cybex Isokinetic Dynamometer; Humac Norm, USA). MAIN RESULTS: Peak isometric upper leg torque showed the greatest age-related difference (-29.0%), followed by muscle quality (-19.1%) and upper leg lean tissue mass (9.8%). SIGNIFICANCE: Cut-points based on Z and T-scores generated from the young adult mean suggest muscle quality demonstrates the greatest construct validity toward the aim of classifying the muscular health of adults. Data generated from large, representative and sex-specific samples are required to adequately classify the muscular health of adults.

It is not known whether different leg positions influence measurements of muscle thickness, pennation angle, and fascicle length. The primary aim of this study was to determine whether extension or flexion of the leg affected measurements of muscle morphology in the vastus lateralis. Thirty-two male professional football players participated in the study. B mode ultrasound (LOGIQ e, GE Healthcare, United States) was used to capture images of the vastus lateralis from the dominant leg of each participant when their leg was (a) extended at the knee and (b) flexed at the knee by 90 degrees. Data were analyzed using paired t tests. Muscle thickness and pennation angle were greater when the leg was extended (2.43 ± 0.18cm vs 2.36 ± 0.17 cm; t(31) = 2.76, P < .010; 18.47 ± 1.18° vs 16.87 ± 1.14°; t(31) = 7.59, P < .001, respectively). Fascicle length was greater when the leg was in flexion (9.87 ± 0.53 cm, flexion vs 9.04 ± 0.92 cm; t(31) = −7.652, P < .001). The intra-rater reliability of the investigator was assessed using a 2-way mixed-effects model. In conclusion, leg position affects measurements of muscle morphology in vastus lateralis; this should be considered when comparing findings between studies.

Background The purpose of this review was to synthesise and determine the age-related change per annum in muscle thickness of the anterior thigh across the adult lifespan. Methods Electronic databases (PubMed, SPORTDiscus and MEDLINE) were searched for primary studies that were screened for eligibility. Results Following screening against eligibility criteria, 27 studies were included in the quantitative analysis. Linear regression revealed a 0.02 cm (95% CI: - .01, -.03, p<0.05) decline in mean muscle thickness per annum from 18-80 years of age, a 0.03cm (95% CI: -.01 to -.05) decline per annum between 20 to 49 years of age and a 0.05cm (95% CI: -.03, - .07) decline per annum between 50 to 80 years of age. There was a 1.5cm (t (25) = 6.12, p<0.05; 95% CI= .98- 1.97cm) mean difference in muscle thickness between the youngest (18-29yrs: 5.13cm ± 0.38) and oldest adults (70-80yrs) 3.63cm ± 0.63). There was no difference in the rate of decline of mean muscle thickness between males (-0.05cm/annum, 95% CI= -.08, -.02) and females (-0.04cm/annum, 95% CI= -.07, -.02). There was a larger difference in anterior thigh muscle thickness between the youngest and oldest in females (4.98cm vs. 3.34cm, 33%, p < 0.05) compared with males (5.23cm vs. 3.98cm, 24%, p <0.05). Conclusion Mean anterior thigh thickness was estimated to decrease at a rate of 0.02cm per annum and this rate of decrease was greater after 50 years of age. Females were more susceptible to age-related reductions in anterior thigh muscle thickness than males.

A male runner (30 years old; 10-km time: 33 min, 46 sec) had been running with suspected insertional Achilles tendinopathy (AT) for ~2 years when the pain reached a threshold that prevented running. Diagnostic ultrasound (US), prior to a high-volume stripping injection, confirmed right-sided medial insertional AT. The athlete failed to respond to injection therapy and ceased running for a period of 5 weeks. At the beginning of this period, the runner completed the Victoria institute of sports assessment-Achilles questionnaire (VISA-A), the foot and ankle disability index (FADI), and FADI sport prior to undergoing an assessment of bi-lateral gastrocnemius medialis (GM) muscle architecture (muscle thickness (MT) and pennation angle (PA); US), muscle contractile properties (maximal muscle displacement (Dm) and contraction time (Tc); Tensiomyography (TMG)) and calf endurance (40 raises/min). VISA-A and FADI scores were 59%/100% and 102/136 respectively. Compared to the left leg, the right GM had a lower MT (1.60 cm vs. 1.74 cm), a similar PA (22.0° vs. 21.0°), a lower Dm (1.2 mm vs. 2.0 mm) and Tc (16.5 ms vs. 17.7 ms). Calf endurance was higher in the right leg compared to the left (48 vs. 43 raises). The athlete began a metronome-guided (15 BPM), 12-week progressive eccentric training protocol using a weighted vest (1.5 kg increments per week), while receiving six sessions of shockwave therapy concurrently (within 5 weeks). On returning to running, the athlete kept daily pain (Numeric Rating Scale; NRS) and running scores (miles*rate of perceived exertion (RPE)). Foot and ankle function improved according to scores recorded on the VISA-A (59% vs. 97%) and FADI (102 vs. 127/136). Improvements in MT (1.60 cm vs. 1.76 cm) and PA (22.0° vs. 24.8°) were recorded via US. Improvements in Dm (1.15 mm vs. 1.69 mm) and Tc (16.5 ms vs. 15.4 ms) were recorded via TMG. Calf endurance was lower in both legs and the asymmetry between legs remained (L: 31, R: 34). Pain intensity (mean weekly NRS scores) decreased between week 1 and week 12 (6.6 vs. 2.9), while running scores increased (20 vs. 38) during the same period. The program was maintained up to week 16 at which point mean weekly NRS was 2.2 and running score was 47.

Background There is a lack of of cross-sectional research that has investigated muscle morphology, function, and functional capability in all age-bands of healthy adults. The primary aim of this study was to evaluate age-related differences in indices of vastus lateralis (VL) muscle morphology, function and functional capability in a sample of healthy males and females aged 18-70yrs. Secondary aims were to evaluate relationships between age and VL muscle morphology and function and functional capability. Methods B mode Ultrasonography and Tensiomyography were used to measure VL muscle thickness, pennation angle, fascicle length, and contractile properties in 274 healthy adults aged 18-70yrs. Measurements of grip strength and functional capability (1-min chair rise test) were also taken. Data analysis included descriptive statistics, correlations, one-way ANOVAs, and multiple regressions. Results Negative correlations were found between age and muscle thickness (rs = -.56), pennation angle (rs = -.50), fascicle length (rs = -.30), maximal displacement (rs = -.24), grip strength (rs = -.27) and the 1-min chair rise test (rs = -.32). Positive correlations were observed between age and the echo intensity of the muscle (rs = .40) and total contraction time (rs = .20). Differences in the indices of muscle health were noticeable between the 18–29 age band and the 50–59 and 60–70 age bands (p < 0.05). The interaction of age and level of physical activity predicted changes in the variables (r2 = .04—.32). Conclusion Age-related differences in muscle health are noticeable at 50 years of age, and age-related differences are larger in females compared to males. It was suggested that the thickness of the VL changed the most with age across the adult lifespan and that physical activity likely acts to abate detrimental change.

Dysfunctional breathing (DB) refers to various abnormalities breathing patterns. Whilst a formal definition exists, subsequent research has inconsistently applied or omitted it. As interest in breathing techniques grows among both healthcare professionals and the public, it is important to reach a consensus on DB's definition to ensure effective assessment and treatment. This critical review explores how DB is currently defined and applied within respiratory and musculoskeletal health. A lack of consistency in the literature identified the need for a more comprehensive framework of DB. To address this, a new model of DB is proposed that includes three subcategories: biomechanical, biochemical and psychophysiological DB. This revised model offers a foundation for future research and clinical application.

This study aimed to characterise selected lower-limb muscle contractile properties in a sample of male professional soccer players, and to investigate if muscle contractile properties differed according to playing position or limb dominance. One hundred and ninety-three male professional soccer players (mean ± SD: age=21.6yrs±4.4; height=181.1cm±10.0; body mass=77.4kg±8.5) had bilateral measurements of muscle contractile properties taken during the pre-season period (June-July) of the 2016-17, 2017-18 and 2018-19 seasons using Tensiomyography. The following muscles were measured: Adductor Magnus (AM), Bicep Femoris (BF), Gastrocnemius Lateralis (GL), Gastrocnemius Medialis (GM), Gluteus Maximus (GT) and Rectus Femoris (RF). Participants were sub-categorised by playing position and limb dominance. Data were analysed using Kruskal Wallis H tests or Mann-Whitney U tests. The left GM muscle produced the shortest delay time (Td) (19.5 ms ± 1.9) and contraction time (Tc) (21.3 ms±14.3) whilst the right BF had the longest sustain time (Ts) (196.9ms±83.9). Relaxation time (Tr) was shortest in the right GL (39.3ms±22.7) and the right GT the largest maximal displacement (Dm) value (10.2mm±3.6). Small differences were present between the left AM Td in Forwards (p=0.005, η2=0.05) and Midfielders and in the left GM Ts between Forwards and Goalkeepers (p=0.04, η2=0.02). The right RF Tc measurement was lower in the right dominant participants (p=0.04, η2=0.35). No other differences were detected between playing positions or limb dominance (p>0.05). The findings from this study provide a profile of lower limb muscle contractile properties in a sample of male professional soccer players. The lack of consistent differences reported between sub-categories suggest that soccer players are homogeneous, regardless of playing position or limb dominance. The data generated from this study may be used to monitor soccer players following periods of inactivity, fixture congestion, long-term injury or acute changes in professional status.

The purpose of this dissertation was to explore the relevance of dysfunctional breathing (DB) in musculoskeletal (MSK) practice. As exposure to breathing practices become increasingly more prevalent across healthcare professionals and the public, and progressively more treatment modalities related to breathing mechanics are emerging, it is important to explore whether breathing mechanics are a relevant consideration within MSK practice. Initially, a critical review was conducted to explore the term ‘dysfunctional breathing’, its definition and the current evidence around DB in MSK health. One suggested formal definition of DB was identified, by Barker and Everard (2015), but there remains no consensus on what DB is within the reviewed literature. One model of DB was also identified (Barker and Everard, 2015), but it needs further modification and adaptation to meet the requirements of the most recent research published on DB. In addition, a literature review of the potential effects that DB can have on the MSK system was conducted. Anatomical, biomechanical, physiological and neurological effects of DB on the MSK system were identified, some grounded in research and others more narrative in nature and needing further exploration. Finally, an explorative focus group interview and one individual interview were conducted to acquire the beliefs and opinions of current MSK practitioners on the relevance of DB, their assessment methods, interventions and their beliefs on what effects DB can have on the MSK system. Thematic analysis was used to develop themes and classifications. This study revealed that DB assessment methods can be classified into three categories: observational assessment, manual assessment, and subjective assessment. Three types of breathing intervention were identified: breathing re-education, breathing exercises, and manual therapy. In total, fourteen potential effects of DB on the MSK system were identified by the participants. Unlike previous research exploring DB this dissertation has only focused on the implications within MSK health as opposed to exploring DB within respiratory and cardiovascular medicine. It adds to the debate of the need for a formal definition of DB and has identified areas for further research that are needed around the perceived effects of DB on the MSK system. In the absence of an overarching and accurate definition a new model of DB has been produced as a result of this dissertation to provide a suggested framework of what DB could potentially look like, when divided into three subcategories. These subcategories are biomechanical DB, biochemical DB and psychophysiological DB It is proposed by this author that the work produced in this study enables a future consensus to be reached on the formal definition, model and signs and symptoms of DB.