Effect Of Longterm Resistance Training On Bone Mineral Density, Muscular Strength, And Balance In Cerebral Palsy

Abstract

Cerebral Palsy (CP) is a non-progressive neurological disorder caused by lesions in the brain leading to musculoskeletal dysfunction and immobility. Physical deconditioning in individuals with CP appears to accelerate muscle atrophy and osteoporosis; thus, adults with CP are more prone to fall and fracture. Balance is also related to the higher risk of fall in the general public, and resistance training is known to improve bone mineral density (BMD), muscular strength, followed by balance. However, equivocal results were reported whether resistance training has a positive effect on BMD, muscular function and balance in CP population. PURPOSE: To determine the influence of long-term resistance training to BMD, muscular strength, and balance in adults with CP who have muscle atrophy and/or osteoporosis. METHODS: 26 adults with and without CP were tested before and after resistance training twice a week for one year. Dual-energy X-ray absorptiometry was used to measure local BMD at the lumbar spine, proximal femur, and radial/ulnar regions. Muscular strength (torque, work, and power) from the lower extremity was assessed at 90, 150, and 210 ⁰/sec using the Humac Norm Isokinetic Dynamometer. The handgrip dynamometer was used for maximal isometric contraction. Balance was measured from the Berg Balance Test, and limits of stability test using the Biodex Balance System. RESULTS: After one year of resistance training, the CP group showed a significant improvement in BMD compared to before training [BMD at femoral neck (0.63±0.08 pre vs. 0.88±0.04 post, g/cm2)]; however, they did not show statistical differences in muscular strength [extensor peak torque (27±9 pre vs. 32±10 post, ft-lbs), flexor peak torque (13±4 pre vs. 12±5 post, ft-lbs)], or balance on limit of stability test [e.g. overall score (32±7 pre vs. 31±6 post)]. However, after training, CP participants who exhibited greater BMD appeared to develop greater muscular strength followed by improved balance. CONCLUSION: These findings suggest that long- term resistance training significantly improved BMD in CP adults without a dramatic improvement in muscular strength or balance. In addition, BMD appeared to play a role in enhanced muscular strength and balance in adults with CP, specifically only those who significantly gained BMD after resistance training.