Marnee J. McKay

Normative reference values for strength and flexibility of 1,000 children and adults

Objective: To establish reference values for isometric strength of 12 muscle groups and flexibility of 13 joint movements in 1,000 children and adults and investigate the influence of demographic and anthropometric factors. Methods: A standardized reliable protocol of hand-held and fixed dynamometry for isometric strength of ankle, knee, hip, elbow, and shoulder musculature as well as goniometry for flexibility of the ankle, knee, hip, elbow, shoulder, and cervical spine was performed in an observational study investigating 1,000 healthy male and female participants aged 3–101 years. Correlation and multiple regression analyses were performed to identify factors independently associated with strength and flexibility of children, adolescents, adults, and older adults. Results: Normative reference values of 25 strength and flexibility measures were generated. Strong linear correlations between age and strength were identified in the first 2 decades of life. Muscle strength significantly decreased with age in older adults. Regression modeling identified increasing height as the most significant predictor of strength in children, higher body mass in adolescents, and male sex in adults and older adults. Joint flexibility gradually decreased with age, with little sex difference. Waist circumference was a significant predictor of variability in joint flexibility in adolescents, adults, and older adults. Conclusions: Reference values and associated age- and sex-stratified z scores generated from this study can be used to determine the presence and extent of impairments associated with neuromuscular and other neurologic disorders, monitor disease progression over time in natural history studies, and evaluate the effect of new treatments in clinical trials.

Reference values for developing responsive functional outcome measures across the lifespan

Objective: To generate a reference dataset of commonly performed functional outcome measures in 1,000 children and adults and investigate the influence of demographic, anthropometric, strength, and flexibility characteristics. Methods: Twelve functional outcome measures were collected from 1,000 healthy individuals aged 3–101 years: 6-minute walk test, 30-second chair stand test, timed stairs test, long jump, vertical jump, choice stepping reaction time, balance (Star Excursion Balance Test, tandem stance eyes open and closed, single-leg stance eyes closed), and dexterity (9-hole peg test, Functional Dexterity Test). Correlation and multiple regression analyses were performed to identify factors independently associated with each measure. Results: Age- and sex-stratified reference values for functional outcome measures were generated. Functional performance increased through childhood and adolescence, plateaued during adulthood, and declined in older adulthood. While balance did not differ between the sexes, male participants generally performed better at gross motor tasks while female participants performed better at dexterous tasks. Height was the most consistent correlate of functional performance in children, while lower limb muscle strength was a major determinant in adolescents and adults. In older adults, age, lower limb strength, and joint flexibility explained up to 63% of the variance in functional measures. Conclusions: These normative reference values provide a framework to accurately track functional decline associated with neuromuscular disorders and assist development and validation of responsive outcome measures for therapeutic trials.

Beighton scores and cut-offs across the lifespan: cross-sectional study of an Australian population

Objectives The primary aim of this study was to evaluate generalized joint hypermobility (GJH) according to the Beighton scoring system in an Australian population. Secondary aims were to identify whether the commonly used Beighton score cut-off of ⩾4 is appropriate, and to suggest age- and sex-specific Beighton score cut-offs across the lifespan. Methods A thousand individuals aged 3-101 years were assessed for GJH with the Beighton scoring system. Differences between age, sex and ethnicity were investigated. The appropriateness of the ⩾4 cut-off was investigated with use of a binary logistic regression. Each Beighton score cut-off was established as the nearest Beighton score that delineated the uppermost 5% of the population. Results Overall, females and non-Caucasians had higher Beighton scores across the lifespan (P < 0.001). Based on a binary logistic regression model, if a cut-off of ⩾4 was utilized, the Beighton scoring system demonstrated a sensitivity of 0.8% and a specificity of 99.3% (P < 0.001). A cut-off of ⩾4 was only found to be appropriate for females aged 40-59 years and males aged 8-39 years. Conclusion Beighton scores varied across the lifespan and were significantly influenced by age, sex and ethnicity. Assessing GJH using the Beighton scoring system required age- and sex-specific cut-off scores based on the uppermost 5% values. This was confirmed by the low sensitivity, high specificity and 60% false-positive rate if a cut-off of ⩾4 was used for both sexes across the lifespan. To lower the risk of a false-positive diagnosis of GJH, further tests of hypermobility need to be utilized.

Safety and efficacy of progressive resistance exercise for Charcot-Marie-Tooth disease in children: a randomised, double-blind, sham-controlled trial

BACKGROUND Exercise is potentially therapeutic for neuromuscular disorders, but a risk of harm exists due to overwork weakness. We aimed to assess the safety and efficacy of progressive resistance exercise for foot dorsiflexion weakness in children with Charcot-Marie-Tooth disease. METHODS We did this randomised, double-blind, sham-controlled trial across the Sydney Childrens Hospitals Network (NSW, Australia). Children aged 6-17 years with Charcot-Marie-Tooth disease were eligible if they had foot dorsiflexion weakness (negative Z score based on age-matched and sex-matched normative reference values). We randomly allocated (1:1) children, with random block sizes of 4, 6, and 8 and stratification by age, to receive 6 months (three times per week on non-consecutive days; 72 sessions in total) of progressive resistance training (from 50% to 70% of the most recent one repetition maximum) or sham training (negligible non-progressed intensity), using an adjustable exercise cuff to exercise the dorsiflexors of each foot. The primary efficacy outcome was the between-group difference in dorsiflexion strength assessed by hand-held dynamometry (expressed as a Z score) from baseline to months 6, 12, and 24. The primary safety outcome was the between-group difference in muscle and intramuscular fat volume of the anterior compartment of the lower leg assessed by MRI (expressed as a scaled volume) from baseline to 6 months and 24 months. Participants, parents, outcome evaluators, and investigators other than the treatment team were masked to treatment assignment. Analysis was by intention to treat. The trial is registered with the Australian New Zealand Clinical Trials Registry, number ACTRN12613000552785. FINDINGS From Sept 2, 2013, to Dec 11, 2014, we randomly assigned 60 children to receive progressive resistance exercise (n=30) or sham training (n=30), and 55 (92%) children completed the trial. ANCOVA-adjusted Z score differences in dorsiflexion strength between groups were 0 (95% CI -0·37 to 0·42; p=0·91) at 6 months, 0·3 (-0·23 to 0·81; p=0·27) at 12 months, and 0·6 (95% CI 0·03 to 1·12; p=0·041) at 24 months. Scaled muscle and fat volume was comparable between groups at 6 months (ANCOVA-adjusted muscle volume difference 0, 95% CI -0·03 to 0·10, p=0·24; and fat volume difference 0, 95% CI -0·01 to 0·05, p=0·25) and 24 months (0, -0·08 to 0·12, p=0·67; and 0, -0·05 to 0·03, p=0·58). No serious adverse events were reported. INTERPRETATION 6 months of targeted progressive resistance exercise attenuated long-term progression of dorsiflexion weakness without detrimental effect on muscle morphology or other signs of overwork weakness in paediatric patients with Charcot-Marie-Tooth disease. FUNDING Muscular Dystrophy Association and Australian National Health and Medical Research Council.

Spatiotemporal and plantar pressure patterns of 1000 healthy individuals aged 3–101 years

OBJECTIVE The purpose of this study was to establish normative reference values for spatiotemporal and plantar pressure parameters, and to investigate the influence of demographic, anthropometric and physical characteristics. METHODS In 1000 healthy males and females aged 3-101 years, spatiotemporal and plantar pressure data were collected barefoot with the Zeno™ walkway and Emed® platform. Correlograms were developed to visualise the relationships between widely reported spatiotemporal and pressure variables with demographic (age, gender), anthropometric (height, mass, waist circumference) and physical characteristics (ankle strength, ankle range of motion, vibration perception) in children aged 3-9 years, adolescents aged 10-19 years, adults aged 20-59 years and older adults aged over 60 years. RESULTS A comprehensive catalogue of 31 spatiotemporal and pressure variables were generated from 1000 healthy individuals. The key findings were that gait velocity was stable during adolescence and adulthood, while children and older adults walked at a comparable slower speed. Peak pressures increased during childhood to older adulthood. Children demonstrated highest peak pressures beneath the rearfoot whilst adolescents, adults and older adults demonstrated highest pressures at the forefoot. Main factors influencing spatiotemporal and pressure parameters were: increased age, height, body mass and waist circumference, as well as ankle dorsiflexion and plantarflexion strength. CONCLUSION This study has established whole of life normative reference values of widely used spatiotemporal and plantar pressure parameters, and revealed changes to be expected across the lifespan.

Forming norms: informing diagnosis and management in sports medicine

Clinicians aim to identify abnormalities, and distinguish harmful from harmless abnormalities. In sports medicine, measures of physical function such as strength, balance and joint flexibility are used as diagnostic tools to identify causes of pain and disability and monitor progression in response to an intervention. Comparing results from clinical measures against ‘normal’ values guides decision-making regarding health outcomes. Understanding ‘normal’ is therefore central to appropriate management of disease and disability. However, ‘normal’ is difficult to clarify and definitions are dependent on context. ‘Normal’ in the clinical setting is best understood as an appropriate state of physical function. Particularly as disease, pain and sickness are expected occurrences of being human, understanding ‘normal’ at each stage of the lifespan is essential to avoid the medicalisation of usual life processes. Clinicians use physical measures to assess physical function and identify disability. Accurate diagnosis hinges on access to ‘normal’ reference values for such measures. However our knowledge of ‘normal’ for many clinical measures in sports medicine is limited. Improved knowledge of normal physical function across the lifespan will assist greatly in the diagnosis and management of pain, disease and disability.

Repeatability, consistency, and accuracy of hand-held dynamometry with and without fixation for measuring ankle plantarflexion strength in healthy adolescents and adults

Introduction: Hand‐held dynamometry (HHD) is commonly used to measure ankle plantarflexion strength but has variable reliability measuring higher forces. Fixed HHD is suggested to improve reliability. We, therefore, compared the reliability, consistency, and accuracy of measuring plantarflexion strength. Methods: Plantarflexion strength was measured in 25 healthy individuals with fixed HHD and HHD alone. Intraclass correlation coefficients (ICC2,2), SEM, minimal detectable change, and Spearman correlation coefficients were calculated to assess inter‐trial repeatability, consistency, agreement, and accuracy. Results: Both methods were repeatable (ICC2,2 0.96 to 0.98) and highly correlated (Spearman rho = 0.815; P < 0.01). Fixed HHD produced significantly higher force outputs. HHD alone provided more consistent force values. Conclusions: Both methods of measuring ankle plantarflexion force were reliable. Force measured with fixed HHD will likely be more accurate for adults and individuals with greater strength, while HHD alone will be more consistent for individuals with lower strength. Muscle Nerve 56: 896–900, 2017

Defining health and disease: setting the boundaries for physiotherapy. Are we undertreating or overtreating? How can we tell?

Overdiagnosis and overtreatment is rife in medicine and has been identified in the discipline of sports medicine,1 as well as many others. Labelling healthy individuals with mild problems as ‘sick’ is concerning, notwithstanding the risks and costs of unnecessary treatment.2 Clinical decision-making depends on understanding the boundaries between health and disease. However, boundaries are often blurred due to complex and interactive psychosocial and cultural factors. In the era of patient-centred care, the goal of treatment should be to address the individual as a whole and enable return to usual daily life. Targeting disability, rather than disease alone, must be a priority for clinicians, particularly in the case of diseases such as osteoarthritis that may be considered ‘par for the course’ of ageing. For example, osteoarthritis is a leading cause of disability worldwide, and this burden is set to rise alongside population ageing. Thus, cost-effective interventions are essential. Identifying disease and discerning when to intervene are salient concerns for clinicians, particularly in light of the problems of overdiagnosis and overtreatment. But when does a joint change from being ‘healthy’ to …

What are the similarities and differences between healthy people with and without pain

Abstract Background and aims: Knowledge of pain characteristics among the healthy population or among people with minimal pain-related disability could hold important insights to inform clinical practice and research. This study investigated pain prevalence among healthy individuals and compared psychosocial and physical characteristics between adults with and without pain. Methods: Data were from 1,000 self-reported healthy participants aged 3–101 years (1,000 Norms Project). Single-item questions assessed recent bodily pain (“none” to “very severe”) and chronic pain (pain every day for 3 months in the previous 6 months). Assessment of Quality of Life (AQoL) instrument, New Generalised Self-Efficacy Scale, International Physical Activity Questionnaire, 6-min walk test, 30-s chair stand and timed up-and-down stairs tests were compared between adults with and without pain. Results: Seventy-two percent of adults and 49% of children had experienced recent pain, although most rated their pain as mild (80% and 87%, respectively). Adults with recent pain were more likely to be overweight/obese and report sleep difficulties, and had lower self-efficacy, AQoL mental super dimension scores and sit-to-stand performance, compared to adults with no pain (p<0.05). Effect sizes were modest (Cohen’s d=0.16–0.39), therefore unlikely clinically significant. Chronic pain was reported by 15% of adults and 3% of children. Adults with chronic pain were older, more likely to be overweight/obese, and had lower AQoL mental super dimension scores, 6-min walk, sit-to-stand and stair-climbing performance (p<0.05). Again, effect sizes were modest (Cohen’s d=0.25–0.40). Conclusions: Mild pain is common among healthy individuals. Adults who consider themselves healthy but experience pain (recent/chronic) display slightly lower mental health and physical performance, although these differences are unlikely clinically significant. Implications: These findings emphasise the importance of assessing pain-related disability in addition to prevalence when considering the disease burden of pain. Early assessment of broader health and lifestyle risk factors in clinical practice is emphasised. Avenues for future research include examination of whether lower mental health and physical performance represent risk factors for future pain and whether physical activity levels, sleep and self-efficacy are protective against chronic pain-related disability.

Knee thrust prevalence and normative hip-knee-ankle angle deviation values among healthy individuals across the lifespan

OBJECTIVE To report the prevalence of varus thrust and normative values for hip-knee-ankle (HKA) angle deviation across the lifespan, and to explore associations between HKA angle deviation and selected clinical factors. DESIGN This was a cross-sectional observational study of 572 participants from the 1000 Norms Project, aged 3-101 years and who self-reported as being healthy. Video recordings (2D) of frontal plane gait were reviewed by physiotherapists for presence of knee thrust and quantification of HKA angle deviation (the difference between HKA angle at initial contact and mid-stance). Age and sex-stratified normative HKA angle deviation values were presented as means and 95% confidence intervals (CIs). Correlations were calculated between HKA angle and clinical measures (age, sex, body mass index (BMI), alignment, knee and hip strength, Knee Injury and Osteoarthritis Outcomes Scores (KOOS), foot posture index, temporo-spatial gait, and hypermobility). RESULTS Overall, 31% of the cohort had varus thrust, most prevalent among adults older than 60 years (42%) and children aged 3-9 (41%). Varus thrust was common in adolescents (25%) and adults aged 20-59 (23%). Mean HKA angle deviation for the entire cohort was 1.2° (95%CI: 1.07, 1.36) towards varus, and 2.1° (95%CI: 1.84, 2.36) among people with clinical varus thrust. Weak associations were identified between HKA angle deviation and BMI, stride width, and KOOS-Sports among adolescents, and in adults weakly associated with height. CONCLUSIONS Prevalence of varus thrust is common across the lifespan. Normative values established here can be readily used by clinicians and researchers in monitoring this gait deviation.