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.

Until recently, strength training in children with cerebral palsy (CP) was considered to be inappropriate, because it could lead to increased spasticity or abnormal movement patterns. However, the results of recent studies suggest that progressive strength training can lead to increased strength and improved function, but low methodological quality and incomplete reporting on the training protocols hampers adequate interpretation of the results. This paper describes the design and training protocol of a randomized controlled trial to assess the effects of a school-based progressive functional strength training program for children with CP.

Background. Rehabilitation of the upper extremity in children with hemiplegic cerebral palsy has not been compared to the same intensity of therapy combined with injected botulinum toxin (BTX). Objective. To measure the short-term (2 weeks) and long-term (6 and 9 months) effects of a standardized functional training program versus without the addition of chemodenervation of forearm and hand muscles. Methods. Twenty children with spastic hemiplegia, aged 4 to 16 years, were matched for baseline characteristics and then randomized to standardized functional physical and occupational therapies for 6 months (PT/OT group) or to the same therapies plus multimuscle BTX-A (BTX+ group). Main outcome measures were isometric generated force, overshoot and undershoot (force production error), active and passive range of motion by goniometry (ROM), stretch restricted angle (SRA) of joints, Ashworth scores at the elbow and wrist, and the Melbourne assessment of unilateral upper limb function. All measures were performed at baseline, 2 weeks after BTX-A, 6 months (end of therapy), and then 3 months after termination of the therapy. Results. Clinical measures (muscle tone, active ROM of wrist and elbow) showed improvement in both groups. However, no significant differences emerged between groups on functional measures. Generated force decreased directly after the BTX-A injection but increased during the therapy period. The PT/OT group, however, showed a significantly higher increase in force and accuracy with therapy compared with the BTX+ therapy group. Conclusions. Functional rehabilitation therapies for the upper extremity increase manual isometric flexor force at the wrist and ROM, but BTX injections cause weakness and do not lead to better outcomes than therapy alone.