Test–retest reliability of handgrip strength measurement in children and preadolescents

This is the final version. Available on open access from MDPI via the DOI in this record. The reliability of handgrip strength (HGS) measurement has been confirmed in adults but has been sparsely addressed in pediatric populations. The aims of this study are twofold: to determine whether sex, age and/or hand-dominance influence the test–retest differences and to establish the reliability level of the HGS measurement in typical developing pediatric participants. A total of 338 participants aged 7–13 years were tested using a digital handgrip strength (HGS) dynamometer (Jamar Plus+ Dynamometer) by the same rater on two testing trials separated by a one-day interval between sessions. The HGS testing was conducted according to the American Society of Hand Therapists recommendations. Relative and absolute reliability statistics were calculated. Age influenced the test–retest difference of the HGS measurement as children compared to preadolescents had lower intraclass correlation coefficients (0.95 vs. 0.98), standard error of measurement (SEM) (0.74 vs. 0.78 kg), smallest detectable difference (SDD) (2.05 vs. 2.16 kg) and higher values of the percentage value of SEM (5.48 vs. 3.44%), normalized SDD (15.52 vs. 9.61%) and a mean difference between the test and retest values (0.50 vs. 0.02 kg) for the dominant hand. The results indicate that the protocol using the Jamar digital handgrip dynamometer is a reliable instrument to measure HGS in participants aged 7–13 years with typical development. Clinicians and researchers therefore can have confidence in determining the minimally clinical effect for HGS

Assessment of Maximal Isometric Hand Grip Strength in School-aged Children.

This is the author accepted manuscript. The final version is available from De Gruyter Open via the DOI in this record.Background: Hand grip strength (HGS) test is commonly used as an indicator of overall muscle strength in medical and sport practices. Recently, several studies have proposed that the measurement of the maximal HGS depends on dynamometer's handle position. The aim of the present study was to identify the optimal handle position to obtain maximal HGS using the hand grip dynamometer (HGD) for school-aged children. Methods: HGS was assessed with the Jamar digital HGD. Each participant performed three maximum contractions of each hand on three handle positions progressing from first to third position. Results: A total of 135 healthy children aged 5-9 years participated in the study. Participants obtained significantly higher results using position 2 than using positions 1 or 3. The maximal mean (± SD) HGS achieved was 9.9 (± 3.1) kg with position 1, 10.4 (± 3.1) kg with position 2, and 9.0 (± 3.2) kg with position 3. Handle position 2 was the most comfortable position for 73% of participants. Conclusions: Our results provide useful methodological information indicating that the second handle position of the Jamar digital HGD is optimal to measure maximal HGS in non-athletic healthy pediatric participants aged 5-9 years

Fast responses to target changes are not impaired in children with spastic hemiplegia.

Contains fulltext : 80728.pdf (publisher's version ) (Closed access)Humans are able to correct an ongoing movement very quickly in response to a suddenly moving target. Such fast responses possibly bypass the motor cortex and if so, one would expect that damage to the motor cortex would not greatly affect them. A group of children with congenital spastic hemiplegia were asked to move to a target, which, in some trials, jumped to a new position. It was found that the congenital spastic hemiplegia group was not affected more by the target jumps than the typically developing children. The moving targets made adaptive movements faster instead of slower for the affected hand. It is concluded that fast-adjusting movements do not necessarily rely on the motor cortex in these children

Children with congenital spastic hemiplegia obey Fitts' Law in a visually guided tapping task.

Contains fulltext : 53281.pdf (publisher's version ) (Closed access)Fitts' Law is commonly found to apply to motor tasks involving precise aiming movements. Children with cerebral palsy (CP) have severe difficulties in such tasks and it is unknown whether they obey Fitts' Law despite their motor difficulties. If Fitts' Law still does apply to these children, this would indicate that this law is extremely robust and that even performance of children with damaged central nervous systems can adhere to it. The integrity of motor control processes in spastic CP is usually tested in complex motor tasks, making it difficult to determine whether poor performance is due to a motor output deficit or to problems related to cognitive processes since both affect movement precision. In the present study a simple task was designed to evaluate Fitts' Law. Tapping movements were evaluated in 22 children with congenital spastic hemiplegia (CSH) and 22 typically developing children. Targets (2.5 and 5 cm in width) were placed at distances of 10 and 20 cm from each other in order to provide Indices of Difficulty (ID) of 2-4 bits. Using this Fitts' aiming task, prolonged reaction and movement time (MT) were found in the affected hand under all conditions in children with CSH as compared to controls. Like in the control group, MT in children with CSH was related to ID. The intercept 'a', corresponding to the time required to realize a tapping movement, was higher in the affected hand of the children in the CSH group. Although, the slope b (which reflects the sensitivity of the motor system to a change in difficulty of the task) and the reciprocal of slope (that represents the cognitive information processing capacity, expressed in bits/s) were similar in both groups. In conclusion, children with CSH obey Fitts' Law despite very obvious limitations in fine motor control

Effectiveness of resistance training in combination with botulinum toxin-A on hand and arm use in children with cerebral palsy: a pre-post intervention study

<p>Abstract</p> <p>Background</p> <p>The aim of this pilot study was to examine the effects of additional resistance training after use of Botulinum Toxin-A (BoNT-A) on the upper limbs in children with cerebral palsy (CP).</p> <p>Methods</p> <p>Ten children with CP (9–17 years) with unilaterally affected upper limbs according to Manual Ability Classification System II were assigned to two intervention groups. One group received BoNT-A treatment (group B), the other BoNT-A plus eight weeks resistance training (group BT). Hand and arm use were evaluated by means of the Melbourne assessment of unilateral upper limb function (Melbourne) and Assisting Hand Assessment (AHA). Measures of muscle strength, muscle tone, and active range of motion were used to assess neuromuscular body function. Measurements were performed before and two and five months after intervention start. Change scores and differences between the groups in such scores were subjected to Mann–Whitney U and Wilcoxon Signed Rank tests, respectively.</p> <p>Results</p> <p>Both groups had very small improvements in AHA and Melbourne two months after BoNT-A injections, without differences between groups. There were significant, or close to significant, short-term treatment effects in favour of group BT for muscle strength in injected muscles (elbow flexion strength, <it>p</it> = .08) and non-injected muscles (elbow extension and supination strength, both <it>p</it> = .05), without concomitant increases in muscle tone. Active supination range improved in both groups, but more so in group BT (<it>p</it> = .09). There were no differences between the groups five months after intervention start.</p> <p>Conclusions</p> <p>Resistance training strengthens non-injected muscles temporarily and may reduce short-term strength loss that results from BoNT-A injections without increasing muscle tone. Moreover, additional resistance training may increase active range of motion to a greater extent than BoNT-A alone. None of the improvements in neuromuscular impairments further augmented use of the hand and arm. Larger clinical trials are needed to establish whether resistance training can counteract strength loss caused by BoNT-A, whether the combination of BoNT-A and resistance training is superior to BoNT-A or resistance training alone in improving active range of motion, and whether increased task-related training is a more effective approach to improve hand and arm use in children with CP.</p