Motor coordination
Motor coordination will be assessed using the MABC-2 and during a series of tasks performed in a motion analysis laboratory. Detailed kinematic and kinetic data will be collected using a three-dimensional motion analysis system (Vicon; Oxford Metrics, inc.) and two AMTI force plates (Advanced Mechanical Technology, inc.). The large (0.6 * 1.2 m) and small (0.6*0.3 m) force plates are located in the middle of the laboratory directly next to one another and will be operated at 1000 Hz. The 14 camera Vicon motion analysis system will be calibrated to collect data in an approximately 5 m
2 area in the middle of the laboratory, running at 250 Hz. Prior to trial performance each child will be fit with the custom full body marker set (seventy two 14 mm retro-reflective markers). This marker set (Table
1) follows a cluster based protocol and allows the accurate calculation of full body joint kinematics and kinetics complicit with the International Society of Biomechanics recommendations [
61,
62].
Table 1
Three-dimensional motion analysis marker set
Head markers |
Eye markers | Placed lateral to canthus of the left and right eyes | R |
Ear markers | Placed above the tragus (or concha) of the left and right ears | R |
Nose marker | Placed on the tip of the nose | V |
Thorax/Back markers
|
Anterior thorax marker | Sternal notch between the two clavicles | R |
Posterior thorax markers | Placed on the 7th cervical and 6th thoracic vertebrae | R |
Pelvis:
|
Anterior pelvis | Right and left anterior superior iliac crests | R |
Posterior pelvis | Right and left posterior superior iliac crest | R |
Lower limbs
|
Thigh markers | Three markers set on a t-bar cluster, with the long bar fixed mid-segment along the iliotibial band. The short bar raps medially onto the quadriceps. | R |
Tibia markers | Three markers set on a t-bar cluster, with the long bar fixed mid-segment along the tibia. The short bar raps laterally towards the fibula. | R |
Knee markers | Four markers placed on the right and left, medial and lateral femoral condyles | V |
Feet markers | Three markers placed on the calcaneus, talus hook and 5th metatarsal | R |
Ankle markers | Four markers placed on the right and left, medial and lateral malleoli | V |
Upper limbs
|
Shoulder markers | Right and left, anterior and posterior shoulder markers | V |
Right and left acromion markers | Three markers placed on the posterior and anterior portion of the lateral border of the acromial plateau, with one marker placed laterally at the base of the acromioclavicular joint. | R |
Right and left upper arm markers | Three markers set on a t-bar cluster, with the long bar fixed mid-segment on the lateral aspect of the upper arm. The short bar raps laterally towards the biceps. | R |
Elbow markers | Right and left, medial lateral epicondyle markers | V |
Forearm markers | Three markers placed on the medial and lateral aspect of the distal third of the forearm, with one marker placed mid segment - between the radius and ulnar, midway up the forearm. | R |
Wrist markers | Right and left, medial and lateral wrist markers placed on the ulnar and radial styloid processes | V |
Hand markers | Three markers, two placed mid-hand medially and laterally. The third marker is placed directly below the junction between the third metacarpal and third proximal phalange. | R |
Finger markers | Two smaller markers (5 mm diameter) fixed to the most distal portion of the index finger, finger nail | R |
Equipment
| | |
Ball markers | Three markers fixed to each ball; tennis ball, t-ball ball, soccer ball | R |
T-ball bat tip | A single marker fixed to the tip of the t-ball bat | R |
Three tasks drawn from common motor performance tools will be used to assess whole body coordination: running, single leg stance and horizontal jump. Running will be performed using the Test of Gross Motor Development, 2
nd edition (TGMD-2; [
63]) protocol which involves running over the 10 meter laboratory runway with children instructed to run as fast as they can. Five trials will be performed. Trials will be deemed successful if the child strikes one of the force platforms with their preferred leg. The starting point of the runway will be adjusted in the instance successful foot strike does not occur and the child will not be informed of this requirement to facilitate natural running technique. Single leg stance will be performed using the MAND [
46] protocol which involves balancing on their preferred foot with the arms free to move for balance, the unused leg held off the floor with slight knee flexion and pivoting allowed but hopping not. Children will be instructed to stand on the large force plate on their preferred foot for as long as they can or until told to stop. Two trials will be completed with a maximum period of 30 seconds for each trial. Horizontal jump will be performed using the TGMD-2 protocol which involves jumping with feet parallel at start and finish. Children will be instructed to jump as far as they can, while 'sticking' their landing and will perform 5 trials. The take-off will be performed from the middle of the small force plate.
Four tasks drawn from common motor performance tools will be used to assess limb coordination: finger-nose, ball strike, ball kick and ball bounce and catch. Finger-nose touch will be performed using the MAND protocol which involves children holding their non preferred arm out in front at shoulder level with the index finger pointed at right angles. The index finger of their preferred hand is used to touch the tip of their nose and the tip of the extended finger moving from supination to pronation. The children will be instructed that it is not a speed test. Ten trials will be performed. Ball strike will be performed using the TGMD-2 Tee ball task which involves a ball being placed on a tee at the height of the child's waist and struck with a bat. The child will be instructed to place their feet shoulder width apart, one on each force plate, facing perpendicular to the intended direction of the t-ball strike and then to hit the ball hard. This task will be repeated 5 times. Ball kick will be performed using the TRMD-2 soccer kick task which involves a ball being positioned on the ground slightly ahead (next to the small force plate) and to the preferred side. Children will be instructed to step forward, from the large force plate onto the small force plate, using their non preferred foot and kick the ball as hard as they can towards a goal. The task will be performed 5 times. The ball bounce and catch task is based on the TGMD-2 ball bounce task and requires the participant to stand on the large force plate and bounce the ball onto the small force plate. Children will be instructed to drop the ball with their preferred hand and catch it with both hands.
Four tasks will be used to assess coordination during active electronic game performance: Move table tennis, Move archery, Kinect table tennis and Kinect soccer penalty kick. For each electronic game task children will be instructed how to perform the task then allowed to practice the task a standard number of times specific to each game. Table tennis will be performed against a computer opponent, with 5 practice points and one game to 11 points repeated on both electronic game consoles. Move archery will be performed against a computer opponent for three trials of 45 seconds. The first set will be used as practice and the final two as assessment trials. The penalty kick trials, performed against a computer opponent, will include one practice trial and three assessment trials.
The primary outcome measures will be the MABC 2 Total Impairment Score, balance as characterised by the length of the path of the centre of mass during the single leg stance trial [
28], and upper limb control as characterised by the normalised length of the trajectory of the finger in the finger-nose task [
64].
Additionally, movement variability will be assessed using the standard deviation of magnitude and rate of change of kinematics and kinetics across the multiple trials of each task; movement smoothness will be assessed using motion pathway rate of change and jerk [
65]; movement efficiency will be assessed using time to stability, out of plane motion and path distance; movement sequencing will be assessed with kinematic chain coupling and time of segmental movement onset; and movement accuracy will be assessed using target error distance. Game performance will also be recorded.
Impact of motor coordination on daily living
Parent report of child coordination difficulties interfering with daily life will be assessed with the revised Developmental Coordination Questionnaire (DCDQ-2007) [
66], which assesses motor difficulties in individuals from 4 to 15 years of age. It has 15-items divided into three subscales: Control During Movement, Fine Motor/Handwriting and General Coordination, and uses a 5 point Likert scale ranging from 1: 'not at all like your child', to 5: 'extremely like your child'. The DCDQ-2007 is self-administered by parents, comparing their child's motor performance with that of their peers. Using translated versions of the DCDQ-2007 a correlation between test and retest of r = .94 was found (p < 0.001; n = 35) [
67]. Factor analysis has verified the three subscales of the DCDQ-2007 explaining 79% of the variance [
68], and concurrent validity has been demonstrated with a significant correlation of r = -.55 between the total score on the DCDQ-2007 and the original MABC [
68].
Physical activity
Time spent in sedentary, light and moderate to vigorous intensity PA, as well as total movement, will be assessed over 7 days using an Actical accelerometer worn on the hip. The Respironics Actical is the most widely used and validated accelerometer in studies of children and adolescents [
69]. Seven days of accelerometer measurement are recommended for the purposes of acceptable measurement of moderate to vigorous PA [
70]. Total weekly activity as well as weekend activity and after school weekday activity will be assessed. Children will keep a brief diary recording accelerometer wear times and PA to assist with accelerometer data quality control and processing.
Mental Health
Harter's Self-Perception Profile for Children [
75] will assess self-perceptions across domains of Scholastic Competence, Social Acceptance, Athletic Competence, Physical Appearance and Behavioural Conduct, and it also includes a subscale designed to evaluate global self-worth that assesses self-esteem independent from the competence domains. It has been validated in samples of children from a wide range of cultural backgrounds, including in Australian children and has high levels of internal consistency ranging from .74 to .92 [
75].
Spence Children's Anxiety Scale [
76] assesses anxiety symptoms in children and consists of six subscales, namely panic attack and agoraphobia, separation anxiety disorder, social phobia, physical injury fears, obsessive compulsive disorder, and generalized anxiety disorder. This self report questionnaire consists of 45 items, 38 assessing specific anxiety symptoms and the remaining six items serve as positive 'filler' items in order to reduce negative response bias. Children are asked to indicate frequency with which each symptom occurs on a four-point scale ranging from Never (scored 0) to Always (scored 3). A total SCAS score is obtained by summing scores of the 38 anxiety symptom items. The scale has high internal consistency for the total score as well as for each subscale, with satisfactory test-retest reliability [
77,
78].
The Short Moods and Feelings Questionnaire [
79] is a self report screening tool to assess depression in children and adolescents aged 8 to 16, that covers areas such as affective, vegetative and cognitive symptoms of depression. This asks the child to rate depressive symptoms in the past 2 weeks on a Likert scale ranging from 0 to 2, with possible responses of "not true," "sometimes true," and "true". It has 3-week and 3-month test-retest reliabilities of .84 and .80, respectively [
80], high internal consistency [
80] and validity with depressive diagnoses derived from standardized diagnostic interviews [
81].