Evaluation of bioelectrical impedance analysis in measuring body fat in 6-to-12-year-old boys compared with air displacement plethysmography.

Air displacement plethysmography (ADP) has been considered as the 'standard' method to determine body fat in children due to superior validity and reliability compared with bioelectrical impedance analysis (BIA). However, ADP and BIA are often used interchangeably despite few studies comparing measures of percentage body fat by ADP (%FMADP) with BIA (%FMBIA) in children with and without obesity. The objective of this study was to measure concurrent validity and reliability of %FMADP and %FMBIA in 6-to-12-year-old boys with and without obesity. Seventy-one boys (twenty-five with obesity) underwent body composition assessment. Ten boys participated in intra-day reliability analysis. %FMADP was estimated by Bodpod using sex- and age-specific equations of body density. %FMBIA was estimated by a multi-frequency, hand-to-foot device using child-specific equations based on impedance. Validity was assessed by t tests, correlation coefficients and limits of agreement (LoA); and reliability by technical error of measurement (TEM) and intraclass correlation coefficients (ICC). Compared with %FMADP, %FMBIA was significantly underestimated in the cohort (-3·4 ± 5·6 %; effect size = 0·42) and in both boys with obesity (-5·2 ± 5·5 %; ES = 0·90) and without obesity (-2·4 ± 5·5 %; ES = 0·52). A strong, significant positive correlation was found between %FMADP and %FMBIA (r = 0·80). Across the cohort, LoA were 22·3 %, and no proportional bias was detected. For reliability, TEM were 0·65 % and 0·55 %, and ICC were 0·93 and 0·95 for %FMBIA and %FMADP, respectively. Whilst both %FMADP and %FMBIA are highly reliable methods, considerable differences indicated that the devices cannot be used interchangeably in boys age 6-to-12 years.

Concurrent Validity of Lower Limb Muscle Strength by Handheld Dynamometry in Children 7 to 11 Years Old.

CONTEXT: The assessment of pediatric muscle strength is necessary in a range of applications, including rehabilitation programs. Handheld dynamometry (HHD) is considered easy to use, portable, and low cost, but validity to measure lower limb muscle strength in children has not been assessed. OBJECTIVE: To determine the concurrent validity of lower limb torque from HHD compared with isokinetic dynamometry (ID) in children aged from 7 to 11 years old. DESIGN: A descriptive assessment of concurrent validity of lower limb joint torques from HHD compared with ID. METHODS: Sixty-one typically developing children underwent assessment of maximal hip, knee, and ankle isometric torque by HHD and ID using standardized protocols. Joint positions were selected to represent maximal strength and were replicated between devices. Concurrent validity was determined by Pearson correlation, limits of agreement, and Bland-Altman plots. RESULTS: Correlations between HHD and ID were moderate to large for knee extension (r 95% CI, .39 to .73), small to large for plantar flexion (r 95% CI, .29 to .67), knee flexion (r 95% CI, .16 to .59), hip flexion (r 95% CI, .21 to .57), hip extension (r 95% CI, .18 to .54), and hip adduction (r 95% CI, .12 to .56), and small to moderate for dorsiflexion (r 95% CI, -.11 to .39) and hip abduction (r 95% CI, -.02 to .46). Limits of agreement for all joint torques were greater than 10% indicating large error in HHD measured torque compared with ID. A positive proportional bias was detected for plantarflexion, indicating that HHD underestimated torque to a greater extent in participants with higher torque values. CONCLUSIONS: Maximal torque values from HHD and ID are consistent with those previously reported in the literature. Poor concurrent validity of HHD may have arisen from issues around joint position, joint stabilization, and the experience of the tester to prevent an isokinetic contraction. Pediatric lower limb muscle strength assessed by HHD should be interpreted with caution.

Muscle strengthening intervention for boys with haemophilia: Developing and evaluating a best-practice exercise programme with boys, families and health-care professionals.

BACKGROUND: Muscle strengthening exercises have the potential to improve outcomes for boys with haemophilia, but it is unclear what types of exercise might be of benefit. We elicited the views of health-care professionals, boys and their families to create and assess a home-based muscle strengthening programme. OBJECTIVE: To design and develop a muscle strengthening programme with health-care professionals aimed at improving musculoskeletal health, and refine the intervention by engaging boys with haemophilia and their families (Study 1). Following delivery, qualitatively evaluate the feasibility and acceptability of the exercise programme with the boys and the study's physiotherapists (Study 2). DESIGN: A person-based approach was used for planning and designing the exercise programme, and evaluating it post-delivery. The following methods were utilized: modified nominal group technique (NGT) with health-care professionals; focus group with families; exit interviews with boys; and interviews with the study's physiotherapists. RESULTS: Themes identified to design and develop the intervention included exercises to lower limb and foot, dosage, age accommodating, location, supervision and monitoring and incentivization. Programme refinements were carried out following engagement with the boys and families who commented on: dosage, location, supervision and incentivization. Following delivery, the boys and physiotherapists commented on progression and adaptation, physiotherapist contact, goal-setting, creating routines and identifying suitable timeframes, and a repeated theme of incentivization. CONCLUSIONS: An exercise intervention was designed and refined through engagement with boys and their families. Boys and physiotherapists involved in the intervention's delivery were consulted who found the exercises to be generally acceptable with some minor refinements necessary.

Protocol for a feasibility randomised controlled trial of a musculoskeletal exercise intervention versus usual care for children with haemophilia.

INTRODUCTION: Haemophilia is a rare, inherited disorder in which blood does not clot normally, resulting in bleeding into joints and muscles. Long-term consequence is disabling joint pain, stiffness, muscle weakness, atrophy and reduced mobility. The purpose of this proposed feasibility of a randomised controlled trial (RCT) is to test the feasibility of an age-appropriate physiotherapy intervention designed to improve muscle strength, posture and the way boys use their joints during walking and everyday activities. METHODS AND ANALYSIS: A small-scale two-centre RCT of a 12-week muscle strengthening exercise intervention versus usual care for young children with haemophilia will be conducted. Primary outcomes will be safety and adherence to the exercise intervention. Secondary outcomes will include recruitment, retention and adverse event rates, clinical data, muscle strength, joint biomechanics and foot loading patterns during walking, 6 min timed walk, timed-up-and-down-stairs, EQ-5D-Y, participants' perceptions of the study, training requirements and relevant costs. Recruitment, follow-up, safety and adherence rates will be described as percentages. Participant diary and interview data will be analysed using a framework analysis. Demographic and disease variable distributions will be analysed for descriptive purposes and covariant analysis. Estimates of differences between treatment arms (adjusted for baseline) and 75% and 95% CIs will be calculated. ETHICS AND DISSEMINATION: The study has ethical approval from the London-Fulham Research Ethics Committee (17/LO/2043) as well as Health Research Authority approval. As well as informing the design of the definitive trial, results of this study will be presented at local, national and international physiotherapy and haemophilia meetings as well as manuscripts submitted to peer-reviewed journals. We will also share the main findings of the study to all participants and the Haemophilia Society.

Biomechanical characteristics of lower limb gait waveforms: Associations with body fat in children.

BACKGROUND: Childhood obesity is associated with musculoskeletal dysfunction and altered lower limb biomechanics during gait. Few previous studies have explored relationships between childhood obesity measured by body fat and lower limb joint waveform kinematics and kinetics. RESEARCH QUESTION: What is the association between body fat and hip, knee and ankle joint angles and moments during gait and in 7 to 11 year-old boys? METHODS: Fifty-five boys participated in the study. Body fat was measured by air displacement plethysmography. Hip, knee and ankle 3D waveforms of joint angles and moments were recorded during gait. Principle component analysis was used to reduce the multidimensional nature of the waveform into components representing parts of the gait cycle. Multiple linear regression analysis determined the association between the components with body fat. RESULTS: Higher body fat predicted greater hip flexion, knee flexion and knee internal rotation during late stance and greater ankle external rotation in late swing/early stance. Greater hip flexion and adduction moments were found in early stance with higher body fat. In mid-stance, greater knee adduction moments were associated with high body fat. Finally, at the ankle, higher body fat was predictive of greater internal rotation moments. SIGNIFICANCE: The study presents novel information on relationships between body fat and kinematic and kinetic waveform analysis of paediatric gait. The findings suggest altered lower limb joint kinematics and kinetics with high body fat in young boys. The findings may help to inform research in to preventing musculoskeletal comorbidities and promoting weight management.

Hip, knee, ankle kinematics and kinetics during stair ascent and descent in healthy young individuals.

BACKGROUND: Few studies have reported the biomechanical aspects of stair climbing for this ergonomically demanding task. The purpose of this ethically approved study was to identify normal functional parameters of the lower limb during stair climbing and to compare the actions of stair ascent and descent in young healthy individuals. METHODS: Thirty-three young healthy subjects, (16 M, 17 F, range 18-39 years) participated in the study. The laboratory staircase consisted of four steps (rise height 18 cm, tread length 28.5 cm). Kinematic data were recorded using 3D motion analysis system. Temporal gait cycle data and ground reaction forces were recorded using a force platform. Kinetic data were standardized to body mass and height. FINDINGS: Paired-samples t tests showed significantly greater hip and knee angles (mean difference standard deviation (SD): hip 28.10 degrees (SD 4.08), knee 3.39 degrees (SD 7.20)) and hip and knee moments (hip 0.25 Nm/kg (SD 0.18), knee 0.17 Nm/kg (SD 0.15)) during stair ascent compared to descent. Significantly greater ankle dorsiflexion angles (9.90 degrees (SD 3.80)) and plantarflexion angles (8.78 degrees (SD 4.80)) were found during stair descent compared to ascent. Coefficient of variation (mean (SD)) in percentage between repeated tests varied for joint angles and moments, respectively (2.35% (SD 1.83)-17.53% (SD 13.62)) and (4.65% (SD 2.99)-40.73% (SD 24.77)). INTERPRETATION: Stair ascent was shown to be the more demanding biomechanical task when compared to stair descent for healthy young subjects. The findings from the current study provide baseline measures for pathological studies, theoretical joint modelling, and for mechanical joint simulators.

Clinical outcome measures for monitoring physical function in pediatric obesity: An integrative review.

OBJECTIVE: Measuring physical function in children with obesity is important to provide targets for clinical intervention to reduce impairments and increase participation in activities. The objective of this integrative review was to evaluate measurement properties of performance-based measures of physical function in children with overweight and obesity. DESIGN AND METHODS: An integrative review of literature published in Cochrane Reviews, SPORTDiscus, CINAHL, PLoS, Medline, and Scopus was conducted. RESULTS: Twenty-eight studies were eligible and represented 66 performance-based measures of physical function. Assessments of repeatability and feasibility were not conducted in the majority of performance measures reported; only 6-min-timed walk (6MTW) was examined for test-retest repeatability. Measures of flexibility, strength, aerobic performance, anaerobic performance, coordination, and balance demonstrated construct validity and responsiveness; however, findings were inconsistent across all performance-based measures. Multi-item tests of physical function demonstrated acceptable construct validity and responsiveness; however, internal consistency was not determined. CONCLUSIONS: There is moderate evidence that 6MTW is suitable for the measurement of physical function in children with obesity. However, evidence is low for the use of aerobic and anaerobic performance, muscle strength, Movement Assessment Battery for Children, and Bruininks-Oseretsky Test of Motor Proficiency multi-item performance instruments and very low for flexibility, coordination, and balance tests. Based on this review, measurement of physical function using 6MTW is recommended.

The impact of body fat on three dimensional motion of the paediatric foot during walking.

Childhood obesity is commonly associated with a pes planus foot type and altered lower limb joint function during walking. However, limited information has been reported on dynamic intersegment foot motion with the level of obesity in children. The aim of this study was to explore the relationships between intersegment foot motion during gait and body fat in boys age 7-11 years. Fat mass was measured in fifty-five boys using air displacement plethysmography. Three-dimensional gait analysis was conducted on the right foot of each participant using the 3DFoot model to capture angular motion of the shank, calcaneus, midfoot and metatarsals. Two multivariate statistical techniques were employed; principle component analysis reduced the multidimensional nature of gait analysis, and multiple linear regression analysis accounted for potential confounding factors. Higher fat mass predicted greater plantarflexion of the calcaneus during the first half and end of stance phase and at the end of swing phase. Greater abduction of the calcaneus throughout stance and swing was predicted by greater fat mass. At the midfoot, higher fat mass predicted greater dorsiflexion and eversion throughout the gait cycle. The findings present novel information on the relationships between intersegment angular motion of the foot and body fat in young boys. The data indicates a more pronated foot type in boys with greater body fat. These findings have clinical implications for pes planus and a predisposition for pain and discomfort during weight bearing activities potentially reducing motivation in obese children to be physically active.

Effects of distally fixated versus nondistally fixated leg extensor resistance training on knee pain in the early period after anterior cruciate ligament reconstruction.

BACKGROUND AND PURPOSE: Nondistally fixated (ie, what is often referred to as "open kinetic chain" [OKC]) knee extensor resistance training appears to have lost favor for some forms of rehabilitation due partly to concerns that this exercise will irritate the extensor mechanism. In this randomized, single-blind clinical trial, nondistally fixated versus distally fixated (ie, often called "closed kinetic chain" [CKC]) leg extensor training were compared for their effects on knee pain. SUBJECTS: Forty-three patients recovering from anterior cruciate ligament (ACL) reconstruction surgery (34 male, 9 female; mean age=29 years, SD=7.9, range=16-54). METHODS: Knee pain was measured at 2 and 6 weeks after ACL reconstruction surgery using visual analog scales in a self-assessment questionnaire and during maximal isometric contractions of the knee extensors. Between test sessions, subjects trained 3 times per week using either OKC or CKC resistance of their knee and hip extensors as part of their physical therapy. RESULTS: No differences in knee pain were found between the treatment groups. DISCUSSION AND CONCLUSION: Open kinetic chain and CKC leg extensor training in the early period after ACL reconstruction surgery do not differ in their immediate effects on anterior knee pain. Based on these findings, further studies are needed using different exercise dosages and patient groups.

Foot loading patterns in normal weight, overweight and obese children aged 7 to 11 years.

BACKGROUND: Childhood obesity is thought to predispose to structural foot changes and altered foot function. Little is currently understood about whether similar changes occur in overweight children. The aim of this study was determine foot loading characteristics in obese, overweight and normal weight children aged 7 to 11 years during level walking. METHODS: Dynamic plantar pressures were measured in 22 obese, 22 overweight and 56 normal weight children recruited from local primary and secondary schools in East London. Peak pressure, peak force, normalised peak force, pressure-time and force-time integrals were analysed at six regions of the plantar foot: lateral heel, medial heel, midfoot, 1st metatarsophalangeal joint, 2nd-5th metatarsophalangeal joint and hallux. A one-way ANOVA was used to test for significant differences in variables across the groups. Where differences existed Tukey post-hoc tests were used to ascertain the location of the difference. RESULTS: Children who were obese and overweight demonstrated significantly (p<0.05) higher peak pressures and peak forces as well as significantly higher force-time and pressure-time integrals under the midfoot and 2nd-5th metatarsal regions. After normalisation of peak force, similar trends existed where the obese and overweight children demonstrated significantly (p<0.05) greater loading at the midfoot and 2nd-5th metatarsals. CONCLUSION: Findings from this study indicated that overweight children, as young as seven, displayed differences in foot loading during walking, when compared with normal weight children. These findings were consistent with loading patterns of children who were obese and suggest that early assessment and intervention may be required in overweight children to mitigate against the development of musculoskeletal complications associated with excessive body mass.

Evaluation of multi-segmental kinematic modelling in the paediatric foot using three concurrent foot models.

BACKGROUND: Various foot models are used in the analysis of foot motion during gait and selection of the appropriate model can be difficult. The clinical utility of a model is dependent on the repeatability of the data as well as an understanding of the expected error in the process of data collection. Kinematic assessment of the paediatric foot is challenging and little is reported about multi-segment foot models in this population. The aim of this study was to examine three foot models and establish their concurrent test-retest repeatability in evaluation of paediatric foot motion during gait. METHODS: 3DFoot, Kinfoot and the Oxford Foot Model (OFM) were applied concurrently to the right foot and lower limb of 14 children on two testing sessions. Angular data for foot segments were extracted at gait cycle events and peaks and compared between sessions by intraclass correlation coefficient (ICC) with 95% confidence intervals (95%CI) and standard error of measurement (SEM). RESULTS: All foot models demonstrated moderate repeatability: OFM (ICC 0.55, 95% CI 0.16 to 0.77), 3DFoot (ICC 0.47, 95% CI 0.15 to 0.64) and Kinfoot (ICC 0.43, 95% CI -0.03 to 0.59). On the basis of a cut-off of 5°, acceptable mean error over repeated sessions was observed for OFM (SEM 4.61° ± 2.86°) and 3DFoot (SEM 3.88° ± 2.18°) but not for Kinfoot (SEM 5.08° ± 1.53°). Reliability of segmental kinematics varied, with low repeatability (ICC < 0.4) found for 14.3% of OFM angles, 22.7% of 3DFoot angles and 37.6% of Kinfoot angles. SEM greater than 5° was found in 26.2% of OFM, 15.2% of 3DFoot, and 43.8% of Kinfoot segmental angles. CONCLUSION: Findings from this work have demonstrated that segmental foot kinematics are repeatable in the paediatric foot but the level of repeatability and error varies across the segments of the different models. Information on repeatability and test-retest errors of three-dimensional foot models can better inform clinical assessment and advance understanding of foot motion during gait.

Biomechanics of lower limb haemophilic arthropathy.

Intermittent joint bleeding and potential arthropathy remain a concern for patients and those responsible for haemophilic care. Monitoring the status of haemophilic joints is a current challenge. Evaluation of bone and soft tissue with radiological imaging together with clinical joint scoring is often used to monitor haemophilic arthropathy and may not be sufficiently sensitive to early changes in joint morphology. Recently an interest in the biomechanical status of haemophilic joints has emerged. Biomechanics is defined as the interdiscipline that describes, analyses and assesses movement in relation to biological and physical principles. This review considers the biomechanical evaluation of haemophilic joint status of the lower limb with particular reference to the evaluation of muscle atrophy, muscle strength, range of motion and gait as well as the relationship to haemophilic arthropathy. In raising the need for increased clinical awareness, this review highlights the need to establish test-retest and inter-rater reliability and ensuring that comparative studies are undertaken with age-matched unaffected peer groups.

The reliability of plantar pressure assessment during barefoot level walking in children aged 7-11 years.

BACKGROUND: Plantar pressure assessment can provide information pertaining to the dynamic loading of the foot, as well as information specific to each region in contact with the ground. There have been few studies which have considered the reliability of plantar pressure data and therefore the purpose of this study was to investigate the reliability of assessing plantar pressure variables in a group of typically developing children, during barefoot level walking. METHODS: Forty-five participants, aged 7 to 11 years, were recruited from local primary and secondary schools in East London. Data from three walking trials were collected at both an initial and re-test session, taken one week apart, to determine both the within- and between-session reliability of selected plantar pressure variables. The variables of peak pressure, peak force, pressure-time and force-time integrals were extracted for analysis in the following seven regions of the foot; lateral heel, medial heel, midfoot, 1st metatarsophalangeal joint, 2nd-5th metatarsophalangeal joint, hallux and the lesser toes. Reliability of the data were explored using Intra Class Correlation Coefficients (ICC 3,1 and 3,2) and variability with Coefficients of Variation (CoV's). RESULTS: The measurements demonstrated moderate to good levels of within-session reliability across all segments of the foot (0.69-0.93), except the lesser toes, which demonstrated poor reliability (0.17-0.50). CoV's across the three repeated trials ranged from 10.12-19.84% for each of the measured variables across all regions of the foot, except the lesser toes which demonstrated the greatest variability within trials (27.15-56.08%). The between-session results demonstrated good levels of reliability across all foot segments (0.79-0.99) except the lesser toes; with moderate levels of reliability reported at this region of the foot (0.58-0.68). The CoV's between-sessions demonstrated that the midfoot (16.41-36.23%) and lesser toe region (29.64-56.61) demonstrated the greatest levels of variability across all the measured variables. CONCLUSIONS: These findings indicate that using the reported protocols, reliable plantar pressure data can be collected in children, aged 7 to 11 years in all regions of the foot except the lesser toes which consistently reported poor-to-moderate levels of reliability and increased variability.

Changes in muscle strength and EMG median frequency after anterior cruciate ligament reconstruction.

The purpose of this study was to monitor neuromuscular changes in quadriceps femoris muscle at 1 and 3 months after anterior cruciate ligament reconstruction (ACLR). Changes in isometric muscle strength (MVC), voluntary activation and surface electromyogram (EMG) parameters were examined in relation to knee stability, pain and swelling in 31 patients (25 M, 6 F) mean (SD) 30(8) years. Physically inactive (RC) and sports participants (SC) acted as controls. Median frequency (Hz) and amplitude (mV) of rectus femoris using Fast Fourier Transform (FFT) 2(11) was calculated during 5-s isometric contractions at 100, 75, 50 and 25% of MVC. One month after surgery, a significant correlation (P < 0.01) was found between activation (%) and MVC of injured knee extensors. By 3 months, most patients were pain free and had achieved full activation but still had muscle weakness. At 1 and 3 months post-surgery and for all levels of MVC contraction, the median frequencies of the injured limbs were significantly lower (P < 0.05) compared to the SC group as were those of the RC group. There was a significant lowering of the median frequencies of the uninjured limbs compared to the SC group at 75 and 100% of MVC. The EMG amplitude of the uninjured and injured limbs mirrored those of the SC and RC groups, respectively. These results support the view that muscle activation patterns were altered following ACL injury and surgical repair and may contribute to subsequent changes in muscle fibre properties during detraining and subsequent retraining.

Range of motion specificity resulting from closed and open kinetic chain resistance training after anterior cruciate ligament reconstruction.

The purpose of this study was to examine whether joint angle specificity occurs in open and closed kinetic chain resistance training of the knee extensors after anterior cruciate ligament reconstruction (ACLR). Isokinetic knee extensor strength was measured at 60 and 210 degrees.s(-1) in 32 patients, 2 and 6 weeks after surgery. Between test sessions, patients participated in a 4-week program of injured leg resistance training of the knee extensors in either open kinetic chain (OKC) knee extension or leg press exercises. Isokinetic testing knee range of motion (ROM) was divided into 5 equal portions from flexion to extension, and the mean torque was calculated over those divisions: 0-20%, 20-40%, 40-60%, 60-80%, and 80-100% ROM. Analysis of variance indicated that there were no significant differences between patients in the knee extension or leg press exercise groups.

Gait analysis 6 and 12 months after anterior cruciate ligament reconstruction surgery.

Little is known about knee function after anterior cruciate ligament reconstruction in the vital activities of walking and stair use. Gait analysis was done on patients 6 months (n = 8) and 12 months (n = 9) after reconstruction of the anterior cruciate ligament. Paired t tests were used to compare the injured and uninjured knees. During level walking, the patients placed external flexion torques on their injured knees throughout midstance, indicating the absence of quadriceps avoidance gait. The peak external flexion torque (resisted by the knee extensor muscles) placed on the injured knee was significantly less than that of the uninjured knee when ascending stairs (at 12 months, 68.4 and 85.3 N-m in the injured and uninjured knees, respectively) and also when descending stairs (at 12 months, 70.8 and 81.7 N-m in the injured and uninjured knees, respectively). The injured knee produced significantly less power than the uninjured knee when ascending stairs, but this difference was not significant when descending stairs. These findings indicate that asymmetric gait patterns persisted up to 1 year after surgical reconstruction and were more pronounced during stair ascent and descent than in level walking. These results indicate that clinicians should include specific interventions targeted at improving knee function during stair use to restore normal function after anterior cruciate ligament reconstruction.