Clodagh Toomey

Ultrasound measurement of subcutaneous adipose tissue thickness accurately predicts total and segmental body fat of young adults.

This study evaluated the ability of ultrasound measurement of subcutaneous adiposity to accurately determine whole body and segmental body fat in young adults aged 18-29 years. Subcutaneous adipose tissue (SAT) thickness was measured by ultrasound at five body sites in 135 subjects (83 men, 52 women) and compared with the corresponding segmental fat mass measured by dual energy X-ray absorptiometry (DXA). Ultrasound measures of SAT thickness were strongly correlated to segmental fat mass and total percentage (%) body fat (r = 0.697-0.907, p < 0.01). Prediction equations generated using quantile regression found SAT thickness at the abdomen and thigh to accurately predict % body fat in men (standard error of the estimate, SEE = 1.9%, 95% limits of agreement (LoA); -3.6% to +3.8%) and SAT thickness at the abdomen and medial calf to accurately predict % body fat in women (SEE = 3.0%, LoA; -6.5% to +5.4%). These data indicate that ultrasound measurement of SAT thickness proportionally reflects segmental fat mass and accurately predicts % body fat in young adults.

Protein Supplementation at Breakfast and Lunch for 24 Weeks beyond Habitual Intakes Increases Whole-Body Lean Tissue Mass in Healthy Older Adults

BACKGROUND Key areas of research on the preservation of lean tissue mass (LTM) during aging are determinations of the protein requirement and optimal protein intake at meals. OBJECTIVE The aim of this study was to determine the effect of protein supplementation at breakfast and lunch for 24 wk beyond habitual intakes on whole-body LTM in healthy adults aged 50-70 y. METHODS In a single-blinded, randomized, controlled design, 60 healthy older men and women (aged 61 ± 5 y) with a body mass index (in kg/m(2)) of 25.8 ± 3.6 consumed either 0.165 g/kg body mass of a milk-based protein matrix (PRO) or an isoenergetic, nonnitrogenous maltodextrin control (CON) at breakfast and midday meals, the lower protein-containing meals of the day, for 24 wk. Dual-energy X-ray absorptiometry was used to measure the change in LTM. RESULTS After the intervention, protein intake in the PRO group increased from 0.23 ± 0.1 to 0.40 ± 0.1 g/kg for breakfast and from 0.31 ± 0.2 to 0.47 ± 2 g/kg for the midday meal. In response, LTM increased by 0.45 (95% CI: 0.06, 0.83) kg in the PRO group compared with a decrease of 0.16 (95% CI: -0.49, 0.17) kg in the CON group (P = 0.006). Appendicular LTM accounted for the majority of the difference in LTM, increasing by 0.27 (95% CI: 0.05, 0.48) kg in the PRO group compared with no change in the CON group (P = 0.002). CONCLUSIONS Protein supplementation at breakfast and lunch for 24 wk in healthy older adults resulted in a positive (+0.6 kg) difference in LTM compared with an isoenergetic, nonnitrogenous maltodextrin control. These observations suggest that an optimized and balanced distribution of meal protein intakes could be beneficial in the preservation of lean tissue mass in the elderly. This trial was registered at clinicaltrials.gov as NCT02529124.

Technical considerations for accurate measurement of subcutaneous adipose tissue thickness using B-mode ultrasound

The search for valid, reliable and inexpensive methods of measuring body composition is an ongoing issue for many researchers. In particular, the measurement of subcutaneous adipose tissue (SAT) is carried out by numerous methods, each with its own drawbacks. Skinfold thickness measurement is the most common in-field method, but it is limited by its tendency to deform the adipose layer, by the limited caliper opening which prevents measurement of larger skinfolds, and the lack of correction for elastic properties of tissue between individuals. Therefore non-invasive field measures which overcome these limitations would be desirable. Ultrasound scanning provides such a device due to its portability and availability, allowing reduced tissue compression and on-screen views of the adipose tissue. Despite a number of papers referring to the use of ultrasound for measuring adipose tissue, the method of measurement has not been fully described. This paper describes our work in determining an accurate method for the measurement of SAT at different body sites, including a comparison of scanning directions and sites. We also describe our investigations into the degree to which compression force through the transducer affects adipose tissue measurement, and the reliability and sensitivity of our methods. We conclude with a recommended reliable scanning protocol for the measurement of SAT.

Generalised equations for the prediction of percentage body fat by anthropometry in adult men and women aged 18-81 years

Anthropometric data indicate that the human phenotype is changing. Todays adult is greater in stature, body mass and fat mass. Accurate measurement of body composition is necessary to maintain surveillance of obesity within the population and to evaluate associated interventions. The aim of the present study was to construct and validate generalised equations for percentage body fat (%BF) prediction from anthropometry in 1136 adult men and women. Reference values for %BF were obtained using dual-energy X-ray absorptiometry. Skinfold thickness (SF) at ten sites and girth (G) at seven sites were measured on 736 men and women aged 18-81 years (%BF 5·1-56·8%). Quantile regression was employed to construct prediction equations from age and log-transformed SF and G measures. These equations were then cross-validated on a cohort of 400 subjects of similar age and fatness. The following generalised equations were found to most accurately predict %BF: Men: (age x 0·1) + (logtricepsSF x 7·6) + (logmidaxillaSF x 8·8) + (logsuprspinaleSF x 11·9) - 11·3 (standard error of the estimate: 2·5%, 95% limits of agreement: - 4·8, + 4·9) Women: (age x 0·1) + (logabdominalG x 39·4) + (logmidaxillaSF x 4·9) + (logbicepsSF x 11·0) + (logmedialcalfSF x 9·1) - 73·5 (standard error of the estimate: 3·0%, 95% limits of agreement: - 5·7, + 5·9) These generalised anthropometric equations accurately predict %BF and are suitable for the measurement of %BF in adult men and women of varying levels of fatness across the lifespan.

Measurement of maximal isometric torque and muscle quality of the knee extensors and flexors in healthy 50‐ to 70‐year‐old women

Muscle quality is defined as strength per unit muscle mass. The aim of this study was to measure the maximal voluntary isometric torque of the knee extensor and flexor muscle groups in healthy older women and to develop an index of muscle quality based on the combined knee extensor and flexor torque per unit lean tissue mass (LTM) of the upper leg. One hundred and thirty‐six healthy 50‐ to 70‐year‐old women completed an initial measurement of isometric peak torque of the knee extensors and flexors (Con‐Trex MJ; CMV AG, Dubendorf, Switzerland) that was repeated 7 days later. Subsequently, 131 women returned for whole‐ and regional‐body composition analysis (iDXA™; GE Healthcare, Chalfont St Giles, Buckinghamshire, UK). Isometric peak torque demonstrated excellent within‐assessment reliability for both the knee extensors and flexors (ICC range: 0·991–1·000). Test–retest reliability was lower (ICC range: 0·777–0·828) with an observed mean increase of 5% in peak torque [6·2 (17·2) N m] on the second day of assessment (P<0·001). The relative mean decrease in combined isometric peak torque (−12·2%; P = 0·001) was double that of the relative, non‐significant, median difference in upper leg LTM (−5·3%; P = 0·102) between those in the 5th and 6th decade. The majority of difference in peak isometric torque came from the knee extensors (15·1 N m, P<0·001 versus 2·4 N m, P = 0·234). Isometric peak torque normalized for upper leg LTM (muscle quality) was 8% lower between decades (P = 0·029). These findings suggest strength per unit tissue may provide a better indication of age‐related differences in muscle quality prior to change in LTM.

Higher Fat Mass Is Associated With a History of Knee Injury in Youth Sport

• STUDY DESIGN: Historical cohort study. • BACKGROUND: History of a knee joint injury and increased fat mass are risk factors for joint disease. • OBJECTIVE: The objective of this study was to examine differences in adiposity, physical activity, and cardiorespiratory fitness between youths with a 3‐ to 10‐year history of sport‐related intraarticular knee injury and uninjured controls. • METHODS: One hundred young adults (aged 15‐26 years; 55% female) with a sport‐related intra‐articular knee injury sustained 3 to 10 years previously and 100 controls matched for age, sex, and sport, who had no history of intra‐articular knee injury, were recruited. Fat mass index (FMI) and abdominal fat (fat mass at the L1 to L4 vertebral levels) were derived using dual‐energy X‐ray absorptiometry. Physical activity and cardiorespiratory fitness were measured using the Godin Leisure‐Time Exercise Questionnaire and the multistage 20‐meter shuttle run test for aerobic fitness, respectively. • RESULTS: Previously injured participants demonstrated higher FMI (within‐pair difference, 1.05 kg/m2; 95% confidence interval [CI]: 0.53, 1.57) and abdominal fat (461 g; 95% CI: 228, 694) than uninjured controls. In multivariable linear regression analysis, previous injury was significantly associated with increased FMI. This increase was attenuated in those who participated in higher levels of physical activity or had higher estimated maximum volume of oxygen. • CONCLUSION: As a risk factor for osteoarthritis in an already susceptible group, excess adiposity is an undesirable trait in the potential pathway to joint disease. Increasing physical activity in this population may be a potential intervention to reduce adiposity thus impede disease initiation and/or progression. • LEVEL OF EVIDENCE: Level 2b.

Exercise Therapy in Juvenile Idiopathic Arthritis: A Systematic Review and Meta-Analysis

OBJECTIVE To conduct a systematic review to evaluate the efficacy of exercise interventions in improving outcomes across domains of functioning and disability in children and adolescents with juvenile idiopathic arthritis (JIA). DATA SOURCES Seven electronic databases were systematically searched up to November 16, 2016. STUDY SELECTION Original data, analytic prospective design, physical therapy-led exercise intervention evaluation, children and adolescents with JIA, and assessment of functional, structural, activity, participation, or quality of life outcomes. DATA EXTRACTION Two authors screened search results, and discrepancies were resolved by consensus. Of 5037 potentially relevant studies, 9 randomized controlled trials and 1 cohort study were included and scored. DATA SYNTHESIS Study quality (Downs and Black quality assessment tool) and level of evidence (Oxford Centre of Evidence-Based Medicine model) were assessed and meta-analysis conducted where appropriate. Alternatively, a descriptive summary approach was chosen. All randomized controlled trials were moderate-quality intervention studies (level 2b evidence; median Downs and Black score, 20 out of 32; range, 15-27). Interventions included aquatic, strengthening, proprioceptive, aerobic, and Pilates exercises. Pediatric activity capacity (Child Health Assessment Questionnaire) improved with exercise (mean difference, .45; 95% confidence interval, .05-.76). Furthermore, descriptive summaries indicated improved activity capacity, body function and structure (pain and muscle strength), and quality of life outcomes. CONCLUSIONS Exercise therapy appears to be well tolerated and beneficial across clinically relevant outcomes in patients with JIA. The paucity of high-quality evidence and study heterogeneity limited the ability to provide conclusive, generalizing evidence for the efficacy of exercise therapy and to provide specific recommendations for clinical practice at this time. Future research evaluating exercise program implementation using validated outcomes and detailed adherence and safety assessment is needed to optimize clinical decision pathways in patients with JIA.

Association between MRI-defined osteoarthritis, pain, function and strength 3–10 years following knee joint injury in youth sport

Background Youth and young adults who participate in sport have an increased risk of knee injury and subsequent osteoarthritis. Improved understanding of the relationship between structural and clinical outcomes postinjury could inform targeted osteoarthritis prevention interventions. This secondary analysis examines the association between MRI-defined osteoarthritis and self-reported and functional outcomes, 3–10 years following youth sport-related knee injury in comparison to healthy controls. Methods Participants included a subsample (n=146) of the Alberta Youth Prevention of Early Osteoarthritis cohort: specifically, 73 individuals with 3–10years history of sport-related intra-articular knee injury and 73 age-matched, sex-matched and sport-matched controls with completed MRI studies. Outcomes included: MRI-defined osteoarthritis, radiographic osteoarthritis, Knee Injury and Osteoarthritis Outcome Score, Intermittent and Constant Osteoarthritis Pain, knee extensor/flexor strength, triple-hop and Y-balance test. Descriptive statistics and univariate logistic regression were used to compare those with and without MRI-defined osteoarthritis. Associations between MRI-defined osteoarthritis and each outcome were assessed using multivariable linear regression considering the influence of injury history, sex, body mass index and time since injury. Results Participant median age was 23 years (range 15–27), and 63% were female. MRI-defined osteoarthritis varied by injury history, injury type and surgical history and was not isolated to participants with ACL and/or meniscal injuries. Those with a previous knee injury had 10-fold (95% CI 2.3 to 42.8) greater odds of MRI-defined osteoarthritis than uninjured participants. MRI-defined osteoarthritis was independently significantly associated with quality of life, but not symptoms, strength or function. Summary MRI-detected structural changes 3– 10 years following youth sport-related knee injury may not dictate clinical symptomatology, strength or function but may influence quality of life.

Muscle strength can better differentiate between gradations of functional performance than muscle quality in healthy 50–70 y women

Highlights • Muscle strength is a better predictor of functional performance than muscle quality.• Extended gait speed is a functionally relevant measure in healthy 50–70 y women.• Healthy adults need functional assessments that allow performance toward maximum.

Knee confidence in youth and young adults at risk of post-traumatic osteoarthritis 3–10 years following intra-articular knee injury

OBJECTIVES To examine differences in knee confidence between individuals with a history of youth sport-related knee injury and uninjured controls. DESIGN Historical cohort study. METHODS Participants include 100 individuals who sustained a youth sport-related intra-articular knee injury 3-10 years previously and 100 age-, sex- and sport-matched uninjured controls. Outcomes included: Knee confidence (Knee Osteoarthritis and Outcome Score); fat mass index (FMI; dual-energy X-ray absorptiometry); and weekly physical activity (modified Godin-Shephard Leisure Time Questionnaire). Mean within-pair differences (95% CI) were calculated for all outcomes. Unadjusted and adjusted (FMI and physical activity) conditional (matched-design) logistic regression (OR 95% CI) examined the association between injury history and knee confidence. RESULTS Median age of participants was 22 years (range 15-26) and median age at injury was 16 years (range 9-18). Forty-nine percent (95% CI; 39.0, 59.0) of previously injured participants were bothered by knee confidence, compared to 12% (5.5, 18.5) of uninjured participants. Although there was no between group difference in physical activity, injured participants had higher FMI compared to controls (within-pair difference; (95% CI): 1.05kg/m2; (0.53, 1.57)). Logistic regression revealed that injured participants had 5.0 (unadjusted OR; 95% CI; 2.4, 10.2) and 7.5 times (adjusted OR; 95% CI: 2.7, 21.1) greater odds of being bothered by knee confidence than controls. CONCLUSIONS Knee confidence differs between individuals with a previous youth sport-related knee injury and healthy controls. Knee confidence may be an important consideration for evaluating osteoarthritis risk after knee injury and developing secondary prevention strategies.