Wearable sensors are portable measurement tools that are becoming increasingly popular for the measurement of joint angle in the upper limb. With many brands emerging on the market, each with variations in hardware and protocols, evidence to inform selection and application is needed. Therefore, the objectives of this review were related to the use of wearable sensors to calculate upper limb joint angle. We aimed to describe (i) the characteristics of commercial and custom wearable sensors, (ii) the populations for whom researchers have adopted wearable sensors, and (iii) their established psychometric properties. A systematic review of literature was undertaken using the following data bases: MEDLINE, EMBASE, CINAHL, Web of Science, SPORTDiscus, IEEE, and Scopus. Studies were eligible if they met the following criteria: (i) involved humans and/or robotic devices, (ii) involved the application or simulation of wearable sensors on the upper limb, and (iii) calculated a joint angle. Of 2191 records identified, 66 met the inclusion criteria. Eight studies compared wearable sensors to a robotic device and 22 studies compared to a motion analysis system. Commercial (n = 13) and custom (n = 7) wearable sensors were identified, each with variations in placement, calibration methods, and fusion algorithms, which were demonstrated to influence accuracy. Wearable sensors have potential as viable instruments for measurement of joint angle in the upper limb during active movement. Currently, customised application (i.e. calibration and angle calculation methods) is required to achieve sufficient accuracy (error < 5°). Additional research and standardisation is required to guide clinical application. This systematic review was registered with PROSPERO ( CRD42017059935 ).

Aim: With evidence for an atrophic effect of botulinum toxin type A (BoNT‐A) documented in typically developing muscles, this study investigated the immediate morphological alterations of muscles in children with cerebral palsy (CP) after BoNT‐A treatment.Method: Fifteen children (10 males, five females; age range 5–11y, mean age 8y 5mo, SD 1y 10mo) with spastic diplegic CP [Gross Motor Function Classification System Levels I (n=9) and II (n=6)] receiving BoNT‐A injections for spasticity management were included. None of the children was a first‐time receiver of BoNT‐A. Magnetic resonance imaging and Mimics software assessed muscle volume, timed 2 weeks before and 5 weeks after injection. All participants received BoNT‐A bilaterally to the gastrocnemius muscle, and five participants also received BoNT‐A bilaterally to the medial hamstring muscles. Functional assessment measures used were the 6‐Minute Walk Test (6‐MWT), the Timed Up and Go (TUG) test, and hand‐held dynamometry.Results: Whilst total muscle group volume of the injected muscle group remained unchanged, a 4.47% decrease in the injected gastrocnemius muscle volume (p=0.01) and a 3.96% increase in soleus muscle volume (p=0.02) was evident following BoNT‐A. There were no statistically significant changes in function after BoNT‐A as assessed by the TUG. There was also no statistically significant change in distance covered in the 6‐MWT. Muscle strength, as assessed using hand‐held dynamometry was also not statistically different after BoNT‐A treatment.Interpretation: Muscle volume decreases were observed in the injected muscle (gastrocnemius), with synergistic muscle hypertrophy that appeared to compensate for this decrement. The 4% to 5% decrease in the volume of BoNT‐A injected muscles are not dramatic in comparison to reports in recent animal studies, and are a positive indication for BoNT‐A, particularly as it also did not negatively alter function.

Purpose: Investigate the combination effects of strength training and Botulinum Toxin Type-A (BoNT-A) on muscle strength and morphology in children with Cerebral Palsy (CP). Methods: Fifteen children receiving BoNT-A, classified as Spastic Diplegic CP, GMFCS I-II, and aged 5–12 years were recruited for this study. Randomly allocated to 10 weeks of strength training either before or after BoNT-A, children were assessed over 6 months. Eight of the 15 children also completed a control period. The Modified Ashworth Scale measured spasticity. The Goal Attainment Scale (GAS) assessed achievement of functional goals. Magnetic Resonance Imaging assessed muscle volume (MV). Instrumented dynamometry assessed strength. Results: Spasticity was significantly reduced following BoNT-A injection (p = 0.033). Children made significant isokinetic strength gains (mean p = 0.022, ES = 0.57) in the intervention period compared to the control period (mean p = 0.15, ES = 0.56). Irrespective of timing, significant strength improvements were seen immediately (10 weeks) and over 6 months for all children. This was also the case for improvements in the GAS (immediately: mean p = 0.007, ES = 4.17, 6 months: mean p = 0.029, ES = 0.99), and improvements in MV in all assessed muscles. Conclusion: The simultaneous use of BoNT-A and strength training was successful in spasticity reduction, improving strength and achieving functional goals, over and above treatment with BoNT-A alone. Muscles targeted for BoNT-A injection should be included in strength training.

To investigate the muscle size-strength relationship of the knee flexors and extensors in children with spastic cerebral palsy (CP) in relation to typically developing children (TD). Eighteen children with spastic Diplegia, Gross Motor Function Classification System I-III (mean 7 y 5 mo SD 1 y 7 mo) and 19 TD children (mean 7 y 6 mo SD 1 y 9 mo) participated. Muscle volume (MV) and anatomical cross-sectional area (aCSA) were assessed using MRI. Measures of peak torque (PT) and work of the knee flexors and extensors were assessed isometrically and isokinetically using a Biodex dynamometer, and normalised to bodymass (Bm). Children with CP were weaker than their TD peers across all torque variables (p < 0.05). MV and aCSA of the knee flexors (MV: p = 0.002; aCSA: p = 0.000) and extensors (MV: p = 0.003; aCSA: p < 0.0001) were smaller in children with CP. The relationship between muscle size and strength in children with CP was weaker than the TD children. The strongest relationship was between MV and isometric PT/Bm for TD children (r = 0.77-0.84), and between MV and isokinetic work (r = 0.70-0.72) for children with CP. Children with CP have smaller, weaker muscles than their TD peers. However, muscle size may only partially explain their decreased torque capacity. MV appears to be a better predictor of muscle work in children with CP than aCSA. This is an important area of research particularly in regard to treatment(s) that target muscle and strength in children with CP. Implications for Rehabilitation This research adds to the evidence that children with CP have smaller, weaker knee flexor and extensor muscles than their TD peers. However, unlike their TD peers, muscle size does not necessarily relate to muscle strength. The weak correlation between MRI-derived muscle volume and isometric peak torque suggests children with CP are underpowered relative to their muscle size. For children with CP, muscle volume appears to be the best predictor of isokinetic muscle torque output. Therefore, when assessing the capacity of a muscle, it appears preferable to measure total muscle volume and torque development through a range of motion (isokinetic strength).

Purpose: To measure activity, participation and QoL in children with CP and to determine how these differ from a comparable group of typically developing (TD) children.Method: A total of eleven males and eight females with CP ranging in age from 5 to 12 years (mean age 7 years 10 months, SD 1 year 10 months; GMFCS level I–II) and 19 age and sex matched TD peers were recruited. Activity was measured using Paediatric Activity Card Sort (PACS), 6-Minute Walk Test and Timed Up and Go Test (TUG). Participation was measured using the assessment of Life Habits (LIFE-H) and quality of life was measured using the Cerebral Palsy Quality of Life Questionnaire (CP-QoL).Results: TD children performed more activities of personal care than children with CP, as assessed via the PACS, t(40) = 3.266, p = 0.002. TD children participate in more life habits than children with CP across all the LIFE-H domains except that of relationships. Results from the CP-QoL indicate that TD children experience a greater QoL in the domains of functioning, t(40) = 2.824, p = 0.007, and participation and physical health, t(40) = 3.543, p = 0.001, than children with CP.Conclusions: These findings encourage the development of therapeutic interventions that aim to reduce these imbalances at all levels of the International Classification of Functioning, Disability and Health.