Biomechanics of recumbent cycling in adolescents with cerebral palsy with and without the use of a fixed shank guide

Abstract

New stationary cycles can decrease motion in the frontal and transverse planes with a shank guide. However, there are no studies comparing cycling with and without this guide. The purpose of this study was to compare cycling with and without a shank guide for adolescents with cerebral palsy (CP). Three males and seven females (15.6 ± 1.8 years) with CP, classified as levels III and IV with the Gross Motor Functional Classification System, underwent biomechanical analysis of stationary recumbent cycling with and without a shank guide at 30 and 60 rpm if able. Data collected included three-dimensional lower extremity joint kinematics using motion analysis, surface electromyography of eight lower extremity muscles, cocontraction of six agonist/ antagonist pairings, efficiency (power output divided by oxygen consumption), and perceived exertion (OMNI Scale of Perceived Exertion). Non-circular data were analyzed via ANOVAs, and circular data were analyzed using circular t-tests. The shank guide altered joint kinematics in all three planes (p < 0.008), had a minor impact on muscle activity (p < 0.006), and had no impact on cocontraction (p > 0.008), efficiency (p = 0.920), or perceived exertion (p = 0.318). The results suggest that a shank guide during cycling may be beneficial for individuals with CP to decrease the amount of hip and knee frontal and transverse plane motion. Knee movement in these planes has been associated with pain in healthy adults; therefore the guide may help to prevent long-term complications from cycling for adolescents with CP.

The Effects of a Shank Guide on Cycling Biomechanics of an Adolescent With Cerebral Palsy: A Single-Case Study

“…For this subject, cycling with the guide allowed her to achieve a faster cycling cadence, which differs from what was seen with our previously reported group data5 in that all of the other children could achieve similar cadences with and without the guide. Higher cadences can lead to higher peak heart rates, which in turn place greater stress on the cardiovascular system.…”

“…Because children with CP have difficulty with acceleration during fast movements, muscle activity for our subject may have needed to increase to meet this demand when cycling at the faster cadence with the guide. Our earlier work with a larger sample size showed minimal and not clinically significant differences in electromyographic activity when cycling with and without a guide5; therefore cadence may be more likely to be the reason for the electromyographic differences seen in this subject.…”

“…Our previous work5 showed that the use of a shank guide designed to limit motion in the frontal and transverse planes during cycling in adolescents with CP led to improvements in joint kinematics during cycling but had minimal impact on the onset and offset of muscle activity and no impact on muscle cocontraction for subjects classified as GMFCS levels III and IV. The purpose of this case report is to describe the biomechanical findings of cycling with and without a shank guide for a subject classified as GMFCS level IV, who had difficulty with the cycling task, and who appeared to benefit more from the shank guide than indicated by our previously reported group data.…”

Comparison of muscle strength, sprint power and aerobic capacity in adults with and without cerebral palsy

“…Muscle strength might, therefore, be the limiting factor in the group with a low physical capacity to perform activities such as cycling, although coordination problems may also play an important role in the group with cP. Johnston et al (4) found that the joint kinematics during cycling in adolescents with cP were different from those for adolescents without cP. they suggested that these differences in joint kinematics may have been due to decreased strength, but also to a decreased motor control.…”

“…Movement problems are a possible reason why people with cP participate in fewer physical activities than age-matched healthy controls. Inactivity in people with disabilities can lead to a cycle of de-conditioning, adversely affecting the cardiovascular system, bone density, and muscular system, and leading to social isolation and decreased self-esteem (3)(4)(5). the level of physical activity of adolescents with cP is inversely related to age (6) and, therefore, adults with cP are most at risk for an inactive lifestyle (7).…”