A deficit to reach the isokinetic velocity in youth wheelchair users with spina bifida.

Introduction: The self-paced adopted by wheelchair users in their postural transfers and locomotion may require sufficient levels of speed-strength in the upper limbs. In clinical practice, we observed limited functional independence and social participation.

Objectives: This study aimed to investigate and compare the speed-strength relationship between wheelchair users with spina bifida (SB) and typically developing youth. In particular, to analyze if SB wheelchair users reached the preset velocities in the isokinetic evaluation of shoulder and elbow.

Design: Cross-sectional observational study.

Setting: Ribeirão Preto Medical School of the University of São Paulo.

Participants and procedures: SB (SB; n = 11) and controls (CT; n = 22) performed the isokinetic assessment of shoulder abductors (SAB), adductors (SAD), flexors (SFL), extensors (SEX), and elbow flexors (EFL) and extensors (EEX) at velocities of 60 and 120degree.s^-1. The analysis of covariance was used to identify the intergroup differences in muscle performance.

Outcome measures: The values of peak torque (PT), power (Pow), time to peak torque (tPT) and the percentage to reach the isokinetic velocity.

Results: The percentage to reach 120degree.s^-1 was moderate-to-low for both groups (26-75.9%). CT presented a significantly greater relative risk of reaching the preset velocities than SB. SB presented higher PT and Pow for SAB and SFL at 60degree.s^-1, higher PT for SFL and EEX at 120degree.s^-1, and lower tPT for SFL at 120degree.s^-1 compared to CT.

Conclusion: SB had difficulty reaching 120degree.s^-1, probably related to neuromuscular differences. However, arm movements in their daily tasks seem to maintain the ability to produce PT and Pow.