Strength, power, and coactivation in children with developmental coordination disorder

Abstract

Strength, power, and coactivation levels were measured during knee extension and flexion tasks in 20 children (13 males, 7 females) with developmental coordination disorder (DCD) and 20 age‐matched control children (12 males, 8 females). Participants were classified according to results obtained on the McCarron Assessment of Neuromuscular Development, with each group including two age levels: 6 to 7 and 9 to 10 years. Tasks were performed on a Biodex dynamometer under isometric and isokinetic conditions with surface EMG recorded from the vastus lateralis and biceps femoris muscles. Significant effects of group and age were observed for the measures of peak torque (isometric and isokinetic) and power, with the decreased power in the group with DCD being more apparent at higher velocities. A lower flexor‐extensor percentage was recorded for the group with DCD but only under isokinetic conditions. From a neuromuscular perspective, the group with DCD had increased levels of coactivation (RMS agonist: RMS antagonist) during the isometric flexion and isokinetic extension actions. Possible causes of the strength and power deficits observed in children with DCD are discussed.

Level walking in adults with and without Developmental Coordination Disorder: An analysis of movement variability

“…This would sit well with the idea that a reduced postural stability may influence the variability of walking as suggested in the ageing literature. This deficit in postural control and different walking patterns may be explained by some of the neuromuscular deficits seen in children with DCD, such as problems of muscle strength and power, and increased co-activation of muscle groups during knee flexion tasks (Raynor, 2001). Other work examining limb control has reported that children with DCD are more variable than TD peers in the timing and force of muscle contractions, both in rhythmic and discrete tasks (Lundy-Ekman, Ivry, Keele, & Woollacott, 1991;Piek & Skinner, 1999).…”

The psychometric properties of the McCarron Assessment of Neuromuscular Development as a longitudinal measure with Australian youth

“…Test-retest reliability correlations after one month for individual items ranged between .67 and .98 for 31 adults with mental disabilities (McCarron, 1997). Concurrent validity of the test with the BOT-1 was established by an Australian research team (Tan, Parker, & Larkin, 2001) and other studies have validated its appropriateness as a motor assessment tool (O'Beirne et al, 1994;Raynor, 2001). …”

“…1) was developed in the United States in 1982 as a screening and evaluation tool for clinicians, educators, allied health professionals and researchers. In Australia, it is one of the most commonly used tests of motor performance (Caeyenberghs, Tsoupas, Wilson, & Smits-Engelsman, 2009;Chia, Guelfi, & Licari, 2010;Hands, Larkin, Parker, Straker, & Perry, 2009;O'Beirne, Larkin, & Cable, 1994;Piek, Dawson, Smith, & Gasson, 2008;Raynor, 2001;Rose, Larkin, & Berger, 1997). Compared to the other commonly used tests, the MAND has a number of advantages.…”

The differences of movement between children at risk of developmental coordination disorder and those not at risk

“…However, follow-up analyses exploring the differences between legs, found significantly greater differences in the variability across the two limbs for children with DCD. Raynor (2001) has shown that children with DCD have neuromuscular problems including lower levels of muscle strength and power and increased levels of coactivation of muscle groups during a knee flexion task. Lundy-Ekman, Ivry, Keele, and Woollacott (1991) found similar neuromuscular problems, indicating difficulties with the selective muscle control necessary for rhythmic coordination.…”