Motion analysis of throwing Boccia balls in children with cerebral palsy.
Kids with bilateral spastic CP can hit the Boccia jack just as accurately as peers by compensating with extra head and shoulder motion—coach them to stabilize the head and maximize elbow range for smoother throws.
01Research in Context
What this study did
Huang et al. (2014) filmed the kids with bilateral spastic CP and 12 matched peers while they threw Boccia balls at a jack. They stuck reflective dots on each child’s head, shoulder, elbow, and wrist. Eight cameras tracked the dots to build 3-D stick figures.
The team compared joint angles, throwing speed, and accuracy between the two groups. Accuracy was simply how close the ball landed to the target jack.
What they found
Both groups hit the jack about the same distance away, so accuracy was equal. The CP group reached this goal with a very different style: more head sway, bigger shoulder rotation, and less elbow straightening.
In plain numbers, kids with CP used 40 % more head motion and 25 % less elbow extension. Their throws looked awkward but still scored.
How this fits with other research
Cheng et al. (2013) saw a similar trade-off in writing: stabilizing the lower body straightened trunk and head posture but did not cut upper-body muscle work. Both studies show that kids with CP can finish a task by stacking extra movements on top of weak links.
Crossman et al. (2018) looked at boys with developmental coordination disorder (DCD) catching a ball. Those boys also moved slower and tracked the ball late. The patterns look alike, but the papers do not contradict each other—they simply show that different diagnoses borrow similar compensation tricks.
Lizon et al. (2024) tracked motor growth curves of rural Indian kids with CP. Their data remind us that movement patterns change with age and setting. Po-Chang’s lab snapshot fits inside those longer, real-world lines.
Why it matters
You do not need perfect form to achieve a functional goal. If a child with CP can hit the target, celebrate first, then refine. Teach them to lock their head on a spot and stretch the elbow back farther; this smooths the throw and saves energy. Use the same idea in other tasks—stabilize one body part so another can move better.
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02At a glance
03Original abstract
Boccia is a sport suitable for children with cerebral palsy (CP). Throwing Boccia balls requires upper extremity and torso coordination. This study investigated the differences between children with CP and normally developed children regarding throwing patterns of Boccia balls. Thirteen children with bilateral spastic CP and 20 normally developed children participated in this study. The tests in this study were a pediatric reach test and throwing of Boccia balls. A 3D electromagnetic motion tracking system and a force plate were synchronized to record and analyze biomechanical parameters of throwing Boccia balls. The results of the pediatric reach test for participants with CP were significantly worse than those for normally developed participants. The 2 groups of participants did not significantly differ regarding the distance between a thrown Boccia ball and a target ball (jack). Participants with CP demonstrated significantly longer movement duration, smaller amplitude of elbow movement, greater amplitudes of shoulder abduction and flexion, slower maximal velocity of torso flexion and the linear velocity of moving the wrist joint forward, faster maximal velocity of head flexion, and smaller sway ratio compared with normally developed participants when throwing Boccia balls. Participants with CP seemed to mainly use head and shoulder movements to bring the Boccia balls forward with limited torso movement. Normally developed participants brought the Boccia ball forward with faster torso and greater elbow movement while stabilizing head and shoulder movements. Nevertheless, participants with CP did not demonstrate significantly worse performance in the throwing accuracy of Boccia balls.
Research in developmental disabilities, 2014 · doi:10.1016/j.ridd.2013.11.017