growthdevelopment77-blog

[growthdevelopment77-blog]

Introduction

Five mixed gender subjects were filmed and observed for this cross-sectional motor task development analysis. Each participant represents a specific developmental stage. The developmental stages and specific age and gender of each participant are as follows:

Early childhood (5-year old male)

Later childhood (11-year old female)

Adolescence (17-year old female)

Early adulthood (20-year old male)

Later adulthood (69-year old female) 

Participants were given the following instructions: “throw the ball to me, over your head using both hands and a step”. The term ‘me’ refers to an observer that stood approximately 4 meters away from the participant. No further details or specific form instructions were given.  

Participants were filmed using 3 cameras, one for each plane of the body (frontal, sagittal, transverse). Each camera was positioned to aim towards the participant’s approximate center of gravity and recorded each throw concurrently. The videos were edited to play each view (frontal, sagittal, transverse) of the throws at full speed, followed by the same views at 0.5x speed, and then 0.25x speed. 

Each movement was broken down into 4 phases to allow for an easier objective comparison between the age groups: 

Starting position 

Cocking and Foot Planting

Acceleration and Ball Release

Follow through 

The videos can be found in the aforementioned order below. Clicking on a video will take you to a separate page that contains a biomechanical description of the two hand overhead throwing skill followed by a developmental analysis.

(241 words)

[growthdevelopment77-blog]

Early Childhood

Starting position: The 5-year old child begins the movement with one foot ahead of the other, with weight placed on his right foot.

Cocking and Foot Planting: The child flexes his shoulders forward with increasing elbow flexion while simultaneously arching his back (torso extension with anterior pelvic tilt) as he begins to step forward with his left foot. As seen in the sagittal and transverse planes, the distal portion of the child’s left foot is rotated medially as he steps forward. As his shoulders approach full flexion around 180 degrees, they also begin to abduct while his elbows continue to flex past 90 degrees, completing the cocking motion. While cocking, the child appears to tuck in his chin (neck flexion). After his foot contacts the ground and his arms complete cocking, the child pauses briefly.

Acceleration and Ball Release: After pausing, the child’s pelvis tilts back, his trunk flexes forward significantly and his elbows and shoulders rapidly extend until ball release. His body weight also begins to transfer to his left foot as his torso passes over it. Upon release, the child hands are pronated, and his arms deviate to his left. As most clearly viewed from the transverse plane, his arms at release are almost fully extended at the elbow and continue to extend well past release.

Follow through:  His elbows complete full extension early during the follow through as his shoulders also proceed towards full extension. The torso continues to flex forward as both knees flex and weight is entirely transferred onto his left foot, lifting his right foot off the ground. His lower right leg externally rotates and the whole leg adducts as he takes a large step to his right to catch his balance, as he nearly falls at the end of the throw.

Discussion: Throughout the throw, the child’s relative lack of muscle and strength hinder his ability to efficiently transfer energy up the kinetic chain. His movements were very staggered, as seen when he pauses between the middle two phases, inhibiting effective momentum transfer and diminishing the efficiency of the throw. This can be explained by his poor ability to plan and sequence segmental movements due to his underdeveloped primary motor cortex (Reillo, Vlahov, Bohren, Leppo, & Davis, 2010). To account for this, the child used his whole body to complete the throw, causing his torso to flex forward excessively and contributing to a loss of balance (Boyd, Johnson, & Bee, 2018). His medially rotated foot during foot placement provides an unstable base of support, which may also be due to his lack of awareness of body position and postural control (Rousanoglou, Noutsos, Bayios, & Boudolos, 2014). During ball release, the child’s left arm deviation displays his limited ability to aim, and maybe also be due to a lack of strength. Similar to the 69-year old yet more dramatic, during the follow through, the child lost his balance and needed to take a step to regain stability. This may be due to his underdeveloped balance and proprioceptive abilities, and inability to properly plan and coordinate movements (Rousanoglou et al., 2014).

(496 words)

[growthdevelopment77-blog]

Late Childhood

Starting Position: The 11-year old child begins the movement with her right foot ahead of her left.

Cocking and Foot Planting: The child takes a step forward with her left foot, fully shifting weight to the lateral aspect of her right foot as she forwards flexes and abducts her shoulders. She also slightly flexes her elbows and continues foot placement with her left foot plantar flexed as it approaches the ground. Her elbows do not complete full flexion during the cocking motion, and her trunk remains relatively neutral through the cocking motion.

Acceleration and Ball Release: The child began the acceleration phase almost immediately after foot contact. Her torso remains neutral throughout the throw.  Upon release, her thumbs are parallel to the ground and are neither in pronation or supination. Her arms remain in line with her body throughout the throw and release occurs near full extension of her elbows. As she releases the ball, she extends her head and neck slightly to look up at the ball. Her right foot plantar flexes, slightly shifting weight to her left foot. She finishes in slight hip flexion with knee extension in her left leg and knee flexion in her right.

Follow through: The child demonstrates minimal movement during her follow through. Her elbows fully extend through the release and her shoulders extend down slowly, but only towards the neutral position. Her lower body does not adjust during the follow through, and her torso experiences very minimal forward flexion as slight weight transfer still occurs into the follow through.

Discussion: The 11-year-old participant’s foot contact stability as well as the continuous nature of her segmental movement improves in comparison to the 5-year old, indicating an enhancement in postural control and muscular coordination (Rousanoglou et al., 2014). Her further developed primary motor cortex allows for better planning and sequencing of movements compared to the 5-year old (Reillo et al., 2010), however, her lack of a fully developed sense of kinesthesia made it necessary for her to utilize additional sensory inputs such as looking up at the ball to judge it’s trajectory and complete the intended movement during the acceleration and ball release phase (Goble, Lewis, Hurvitz, & Brown, 2005). Furthermore, her limited elbow and shoulder flexion and lack of forward trunk flexion during the cocking phase display her inability to utilize proximal-to-distal segmental motion, necessary for optimizing neuromuscular contributions that allow for maximal energy and momentum transfer, which are learned through experience (Grimpampi, Masci, Pesce, & Vannozzi, 2016). Her lack of height and musculature may have also contributed to the inefficient transferring of energy and momentum through her body (Spear, 2002). However, she did not pause mid-throw, and therefore still transferred her weight from her right to left foot far more efficiently than the 5-year old. This indicates an advancement in the development of sensorimotor integration abilities, sense of postural control, and improvement in fluid sequential movement (Singh & Scott, 2003).

(462 words)

[growthdevelopment77-blog]

Adolescence

Starting Position: The 17-year old adolescent begins with both feet next to each other, approximately shoulder width apart. Her hips and torso are in a neutral upright position.

Cocking and Foot Planting: The adolescent flexes her shoulders forward, with her elbows extended until approximately 90 degrees of shoulder flexion, at which point she begins to flex her elbows and abduct her shoulders as well.  As she cocks her arms back, she takes a step forward with her right foot and flexes her torso forward. When fully cocked, her elbows are fully flexed (past 90 degrees) and her shoulders are nearly fully abducted.

Acceleration and Ball Release: The adolescent transitions to the acceleration phase immediately at the end of cocking, as her right foot contacts the ground in a dorsiflexed position. Her trunk remains upright for most of the movement, with slight bending forward towards the end that is more of a result of carrying her body weight onto her extended leg than of torso flexion. She extends her shoulders and elbows. Her release of the ball involves fully pronating her wrists in-between her arms during the release. She releases with her elbows near full extension and steps forward through her entire throw, finishing the throwing movement while beginning to extend her right hip, fully extending her slightly bent right knee and plantar flexing her left foot.  

Follow through: The adolescent demonstrates minimal follow through. Upon reaching full elbow extension, her arms remain in the same degree of shoulder flexion, which is unlike the large degree of shoulder extension seen in both younger age groups. Much of her follow through was initiated through the forceful pronation and wrist flexion that can be observed at release.

Discussion: The adolescent’s dorsiflexed foot placement provided her with greater stability than both the childhood subjects, indicating an advancement in her sensorimotor integration abilities and sense of postural control (Singh & Scott, 2003). Her more developed primary motor cortex allowed her to overcome the difficulties earlier age groups faced, such as the 5-year old’s lack of motor planning and the 11-year old’s lack of kinesthesia that required her to look at the ball during the throw (Goble et al., 2005). Although to lesser degree than the 20-year-old, the adolescent incorporated trunk flexion prior to foot contact, a movement seen in proficient throwers (Stodden, Langendorfer, Fleisig, & Andrews, 2006). This movement was absent in the earlier age groups and demonstrates the adolescent’s development of optimized neuromuscular influences, allowing for efficient energy and momentum transfer through her utilization of proximal-to-distal segmental motion (Grimpampi et al., 2016). Her increased height and weight also contribute to this improved momentum transfer when compared to the younger age groups, resulting in an overall more efficient movement (Puciato, Mynarski, Rozpara, Borysiuk, & Szygula, 2011). Finally, when compared to the younger subjects, both the adolescent’s improved coordination between body parts and her increased moment arm length allowed for smaller joint movement, as it allowed her to accelerate the ball faster prior to release (Nagano & Komura, 2003).

(475 words)

[growthdevelopment77-blog]

Early Adulthood

Starting Position: The 20-year old participant starts with his right foot well ahead of his left and elbows slightly flexed.

Cocking and Foot Planting: The participant takes a step forward as he flexes and begins to abduct his shoulders. His elbows simultaneously flex slightly past 90 degrees, bringing himself into a cocked position with a slight stretch. At the same time, his left leg continues travelling straight and his foot dorsiflexes before it contacts the ground while his right hip and knee extend. His torso and pelvis remain neutral for the majority of this phase, only beginning to flex forward when transitioning.

Acceleration and Ball Release: As the participant begins to accelerate the ball, weight is transferred onto his left foot as it completes its contact with the ground. His elbows and shoulders extend immediately after they are stretched. His trunk flexes forward and his right foot begins to plantarflex. Upon release, his hands remain neutral. His elbows and shoulders remain flexed slightly past 90 degrees upon release of the ball. His right hip is in extension while his left hip is in flexion, and both knees are slightly flexed. His torso flexes 30 degrees forward, forming a straight line between his right leg and his shoulders.

Follow through: The participant’s elbows follow through the release into full extension, followed by shoulder extension to neutral, ensuring the ball leaves his hands accelerating. A smooth weight transfer continues until well after ball release as the torso flexes over a slowly extending lead leg and hip. His right hip extends further and right foot plantar flexes to aid in the weight transfer process.

Discussion: This participant has undergone the motor developmental changes required of a proficient thrower. Unlike the 5 and 11-year old participants, this participant’s dorsiflexion-initiated foot placement provided him with the optimal base of support needed for smooth transfer of momentum from the step to the throwing arm (Brockett & Chapman, 2016). This was likely due to his developed sensorimotor integration abilities and sense of postural control, as he was likely aware, subconsciously, that dorsiflexed foot placement provided optimal stability (Singh & Scott, 2003). Furthermore, he demonstrated continuous sequential movement with a proficiency higher than any other age group, indicating full development of the muscle coordination required for optimal energy transfer (Rousanoglou et al., 2014). He utilizes the elastic nature of muscle and accelerates just after his muscles are stretched to obtain increased force. He also demonstrated greater proximal-to-distal segmental motion as he performed greater forward trunk flexion than the 17-year-old, as well as an increased duration of acceleration and follow-through that demonstrate his optimized neuromuscular contributions allowing for maximal energy transfer (Stodden et al., 2006). The 20-year-old effectively drives the forward momentum of his step into the throw through his seamless transitions and right foot plantarflexion. This forward momentum accumulated during the acceleration phase and continued throughout the entirety of the throw, allowing for a smaller range of elbow movement compared to the 5-year-old. This motor improvement can be attributed to the 20-year-old’s complete development of coordination between body parts (Kasuyama, Mutou, & Sasamoto, 2016).

(495 words)

[growthdevelopment77-blog]

Later Adulthood

Starting Position: The 69-year old participant starts with her feet together, approximately shoulder width apart with her elbows flexed.

Cocking and Foot Planting: The participant flexes and slightly abducts her shoulders forward with her elbows continuing to flex, but only to 90 degrees. Her left leg is extended straight-on and she initiates foot contact in dorsiflexion as her arms cock back. Her torso is slightly extended, and she begins to transition to acceleration well before foot contact occurs. Her final cocked position has relatively shallow shoulder flexion.

Acceleration and Ball Release: The participants left foot is in the air while initiating acceleration and is planted as the ball is released. Her torso ends in slight flexion upon release of the ball. The range she travels through torso extension to flexion is minimal. Weight is shifted from right to left foot. Upon release, the participant forcefully pronates her hands through the throw and extends her neck. Her arms deviate to the left, as does the ball. Her hands do not follow the same trajectory as her left hand follows through the motion faster. Release occurs with the elbows flexed slightly less than 90 degrees, meaning that there was very minimal flexion occurring at the elbow during the throw. She leans to her left after release to stabilize her center of gravity over her stepping foot.

Follow through: The participant’s elbows quickly end in near full extension, but her shoulders extend slower than other groups following release and not in synchrony with one another. Her left arm extends at a faster rate than her right. Her torso continues to flex forward as weight continues to transfer onto her left foot. The left hip and knee extend, just as observed in our other groups.

Discussion: This participant’s foot placement provided her with a stable base of support, as she initiated foot placement with her legs travelling straight and with her feet in dorsiflexion (Brockett & Chapman, 2016), indicating that her balance and sensorimotor abilities are intact (Brown, Neva, Feldman, Staines, & Boyd, 2018). However, this participant lacked the trunk flexion prior to foot contact as seen in our 20 and 17-year-old participants, which indicates a diminished ability to optimize energy transfer (Morrison & Newell, 2012). Furthermore, her elbows moved through a smaller range of flexion and extension than other groups which is due to reduced joint flexibly and musculoskeletal constraints that come with age (Stathokostas, McDonald, Little, & Paterson, 2013). All younger groups began elbow flexion at 90 degrees of shoulder flexion, whereas older groups had them flexed the whole time. The 69-year old participant’s slower left hand follow-through can be explained by the sarcopenia and muscular atrophy in her non-dominant, left arm, another consequence of aging (Novotny, Warren, & Hamrick, 2015). Although she initiated the throw with a stable base of support, the unbalanced termination of the throw indicated that her balance abilities are on the onset of decline. Finally, as unobserved in all other age groups, the participant attempted to stabilize her center of gravity following ball release, which may be due to loss of balance and proprioception that come with age (Ribeiro & Oliveira, 2007). 

(495 words)

[growthdevelopment77-blog]

Conclusion

The sequence of principal motor developmental changes associated with the overhead throw were demonstrated by our five participants. Their throwing characteristics followed the anticipated patterns of development, emphasizing the significance that age has on motor abilities and skills.

Through the analysis of our five subjects, it can be concluded that throwing proficiency, and therefore overall motor abilities, share a curvilinear relationship with age due to the developing and aging brain. This finding is consistent with, and is well substantiated in current literature (Leversen, Haga, & Sigmundsson, 2012). Throwing proficiency seemed to increase with age and peak during young adulthood, as seen in the 20-year-old participant, and began to decline past young adulthood, as seen in the 69-year-old participant. This pattern was seen in most movements during each phase of the throw, but mostly in regard to overall fluidity and efficiency as a whole.

Stability during the foot contact phase improved with age, demonstrating the development of sensorimotor integration that allowed for improved postural control and muscular coordination (Brockett & Chapman, 2016).

Furthermore, the participants’ abilities to optimize energy transfer and momentum also increased with age, up until young adulthood, as demonstrated by their increase in forward trunk flexion and quality of continuous sequential motion (Rousanoglou et al., 2014). These developmental changes can be attributed to the improvement of neuronal circuits that collect and integrate information, ultimately leading to precisely timed skeletal muscle contractions that summate and allow for optimal movement (Arber, 2012).

The efficiency of the ball release was the worst in both early childhood and late adulthood, and improved with age up until early adulthood, which reinforces the curvilinear relationship between throwing proficiency and age. Left arm deviation was seen only in the 5- and 69-year old participants, due to their lack of full muscular development and potential muscular atrophy, respectively. After the follow through, both the child and older adult had to take a step to correct their imbalances due to their lack of fully developed balance and proprioception abilities, and deterioration of balance abilities, respectively (Ribeiro & Oliveira, 2007).

Although these limitations are inevitably affected by the onset and decline of primary aging factors, measures can be taken to aid and improve these hindrances (Boyd et al., 2018). An example of this is increasing exposure to physical activity with a focus on throwing games in ‘play time’ settings for the early childhood age group (Kasuyama et al., 2016). In addition, engaging in neuromuscular and balance training has been shown to improve the stability and control of older adults in gross and fine motor movement tasks. These practices can be beneficial to the older age group as they are the most at risk demographic for hip fractures resulting from falls (Gschwind et al., 2013).

Overall, all five subjects were consistent with the anticipated motor developmental changes that come with age, effectively illustrating the curvilinear relationship between throwing proficiency and age cross-sectionally.

(452 Words)

[growthdevelopment77-blog]

References

|

Arber, S. (2012). Motor Circuits in Action, Specification, Connectivity, and Function. Neuron, 74(6), 975–989.

Boyd, D., Johnson, P., & Bee, H. (2018). Lifespan Development Sixth Canadian Edition. Toronto: Pearson Canada.

Brockett, C. L., & Chapman, G. J. (2016). Biomechanics of the Ankle. Orthopaedics and Trauma, 30(3).

Brown, K., Neva, J., Feldman, S., Staines, W., & Boyd, L. (2018). Sensorimotor integration in healthy aging: Baseline differences and response to sensory training. Journal of Experimental Gerontology, 112, 1–8.

Goble, D. J., Lewis, C. A., Hurvitz, E. A., & Brown, S. H. (2005). Development of upper limb proprioceptive accuracy in children and adolescents. Human Movement Science, 24, 155–170. https://doi.org/10.1016/j.humov.2005.05.004

Grimpampi, E., Masci, I., Pesce, C., & Vannozzi, G. (2016). Quantitative assessment of developmental levels in overarm throwing using wearable inertial sensing technology. Journal of Sport Sciences, 34(18), 1–7.

Gschwind, Y. J., Kressig, R. W., Lacroix, A., Muehlbauer, T., Pfenninger, B., & Granacher, U. (2013). A best practice fall preventional exercise program to improve balance, strength/power, and psychosocial health in older adults: study protocol for a randomized controlled trial. BMC Geriatrics, 13, 105.

Kasuyama, T., Mutou, I., & Sasamoto, H. (2016). Development of Overarm Throwing Technique Reflects Throwing Ability during Childhood. Physical Therapy Research, 19(1), 24–31.

Leversen, J. S., Haga, M., & Sigmundsson, H. (2012). From Children to Adults: Motor Performance across the Life-Span. PLoS One, 7(6).

Morrison, S., & Newell, K. M. (2012). Aging, Neuromuscular Decline, and the Change in Physiological and Behavioral Complexity of Upper-Limb Movement Dynamics. Journal of Aging Research, 2012(3).

Nagano, A., & Komura, T. (2003). Longer moment arm results in smaller joint moment development, power and work outputs in fast motions. Journal of Biomechancis, 36(11), 1675–1681.

Novotny, S. A., Warren, G. L., & Hamrick, M. W. (2015). Aging and the Muscle-Bone Relationship. Physiology (Bethesda), 30(1), 8–16.

Puciato, D., Mynarski, W., Rozpara, M., Borysiuk, Z., & Szygula, R. (2011). Motor Development of Children and Adolescents Aged 8-16 Years in View of Their Somatic Build and Objective Quality of Life of Their Families. Journal of Human Kinetics, 28, 45–53.

Reillo, M., Vlahov, E., Bohren, J., Leppo, M., & Davis, D. (2010). Preschool Children’s Level of Proficiency in Motor Skills and the Level of their Physical Fitness as Adolescents. The Sport Journal, 13(3).

Ribeiro, F., & Oliveira, J. (2007). Aging effects on joint proprioception: the role of physical activity in proprioception preservation. European Review of Aging and Physical Activity, 4(2), 71–76.

Rousanoglou, E., Noutsos, K., Bayios, I., & Boudolos, K. (2014). Ground Reaction Forces and Throwing Performance in Elite and Novice Players in Two Types of Handball Shot. Journal of Human Kinetics, 40(1), 49–55.

Singh, K., & Scott, S. H. (2003). A motor learning strategy reflects neural circuitry for limb control. Journal of Nature Neuroscience, 6(4).

Spear, B. A. (2002). Adolescent Growth and Development. Journal of the American Dietetic Association, 102(3), 23–29.

Stathokostas, L., McDonald, M. W., Little, R. M. D., & Paterson, D. H. (2013). Flexibility of Older Adults Aged 55-86 Years and the Influene of Physical Activity. Journal of Aging Research, 2013(3).

Stodden, D. F., Langendorfer, S. J., Fleisig, G. S., & Andrews, J. R. (2006). Kinematic Constraints Associated With the Acquisition of Overarm Throwing Part I. Research Quarterly for Exercise and Sport, 77(4).