Isokinetic arm and shoulder muscle torque-velocity characteristics in mobility limited children and adolescents with spina bifida

INTRODUCTION

Propulsive wheelchair capacity may be influenced by arm muscle performance.Objectives: To determine whether children and adolescent wheelchair-users with spina bifida show reduced arm muscle strength compared to their typically developing peers and to compare muscle strength data obtained by isokinetic and handheld dynamometry (HHD).

METHODS

Participants (mean age 12.5 ± 2.5 years) were assigned to spina bifida (SB; n = 11) or control (n = 22) groups. Isokinetic dynamometry was used to measure peak torque (PT) during dynamic (60°s-1 and 120°s-1) and isometric strength testing (MVIC) for shoulder and elbow flexors and extensors. HHD was used to measure MVIC of the same muscle groups.

RESULTS

SB showed reduced isokinetic PT for shoulder extensors at 60°s-1 and 120°s-1, shoulder flexor MVIC, and elbow flexors at 60°s-1 and MVIC; higher PT for shoulder flexors and elbow flexors at 120°s-1; and decreased MVIC for elbow flexors but not extensors compared to controls when assessed by HHD. The SB and control groups showed strong positive correlations between MVIC data obtained by the two devices for all muscle groups (r ≥ 0.81; p < .01), except for shoulder flexor MVIC in controls (r = 0.68; p < .01).

CONCLUSION

SB presented reduced levels of dynamic slow-speed and isometric shoulder and elbow muscle strength and greater dynamic high-speed shoulder and elbow flexor strength than controls possibly due to the exposure to self-sustained wheelchair ambulation. Exercise-based intervention protocols to increase slow-speed arm muscle strength should be considered in youth with SB. Strong positive correlations observed between muscle strength assessed by isokinetic dynamometry and HHD support the use of HHD in this clinical population.

Decreased respiratory performance of children and adolescents with myelomeningocele who use a wheelchair - preliminary data

Myelomeningocele (MMC) is a neural tube defect that often causes spinal cord injury at the thoracolumbar region, as well as sensory and motor paralysis in the lower limbs. This leads to continuous use of a wheelchair and, consequently, a sedentary lifestyle, predisposition to muscle weakness, cardiovascular and respiratory disorders, obesity, and structural alterations in the spine. We assessed the respiratory function and shoulder strength of MMC participants who were wheelchair-users and had no respiratory complaints and compared them to healthy children and adolescents. MMC (n=10) and healthy (n=25) participants of both genders with a mean age of 12.45 years (SD=2.1) were assessed for weight, height, respiratory performance, and isometric peak for shoulder flexors, extensors, abductors, and adductors, using an isokinetic dynamometer. Medullary lesion, functional levels, and abnormal curvatures of the spine were assessed for MMC participants. The level of spinal cord injury for the majority of the MMC participants was high lumbar and they had scoliosis. MMC showed lower values for forced vital capacity, forced expiratory volume at the first second, forced expiratory flow (25-75%), maximal voluntary ventilation, and isometric peak for shoulder flexors and adductors compared to healthy participants. This indicated a decreased vital capacity, respiratory muscle endurance, and shoulder muscle strength.