ri-disc-ulous-6-blog

[ri-disc-ulous-6-blog]

Introduction

The purpose of this blog is to dissect and analyze the age-related changes that affect the performance and execution of throwing a frisbee across multiple age cohorts. While throwing a frisbee may seem like a simple and childish task, the technique one uses can have a dramatic effect on the accuracy and distance of the trajectory. For the purpose of this examination, the optimal technique for a back-handed frisbee throw will be broken down into 3 phases: the wind-up phase, the acceleration phase, and the follow-through phase.

The wind-up phase consists of a proper grip on the frisbee, medial rotation of the torso, and adduction of the arm and flexion of the elbow into a “cocked” position. This position stores potential kinetic energy to be used during the acceleration phase.

The acceleration phase consists of abducting the arm and extending the elbow while rotating the torso laterally. This accelerates the frisbee forward, using the kinetic energy stored in the wind-up phase. At the end of the acceleration phase is the release. The frisbee should be released parallel to the horizontal plane around the abdominal level.

The follow-through phase occurs after the release, where the entire body (hips, chest, arms, shoulders) are uncoiled.

(Word Count: 199)

[ri-disc-ulous-6-blog]

2-6 Year Old Participant

Our 5-year-old participant in the early childhood category (2-6-year-old) demonstrated a considerably less skilled throwing technique compared to our older participants.  We can explain many of the biomechanical weaknesses of his throw by looking at some of the developmental differences between early childhood and other age groups.  The early childhood age group shows significant increases in bone growth and muscular development.  In this period, the average child (male or female) grows from a range of 5-8 cm and 2.7 kg annually (Boyd et al,. 2018).  These new changes allow the child to explore their environment more so than ever before, but a slow learning curve is present as the child requires time to learn what their growing body is capable of  (Freitas, et al., 2018).

In terms of biomechanics, his throw was what we would expect from a child of his age.  As opposed to doing a traditional backhand frisbee throw, he used an overhead throwing technique similar in form to what we see when a young child throws a tennis ball.  Our participant demonstrated a very short wind-up phase where he flexed his elbow to 90 degrees, retracted his shoulder blades, and externally rotated his shoulder slightly.  However, after entering this “cocked position” (his body position when the video began), he paused and lost his momentum.  As a result, he chose to do a tiny additional backswing in order to begin the movement.  The delay we see is likely because he is in the cognitive stage of skill development for throwing objects (Wulf, 2007).  In other words, the skill is relatively new to him so it requires more attentional resources to execute.  In the early childhood stage of development, there are considerable advances in gross motor coordination.

Another reason why he may have struggled is that running, catching and throwing balls are common activities, but throwing a frisbee is not as common of an activity for this age.  More practice is needed to improve on the coordinated muscle contractions that are required to throw a frisbee properly.  During early childhood, axons are continuing to myelinate, which will help improve the rate of neuromuscular communication (Boyd et al., 2018).  

Notably, the 5-year-old participant generated the majority of force for the throw with elbow extension.   A more skilled backhand thrower would recognize that they can generate greater upper limb acceleration by including other body segments in the throw as well (i.e. torso rotation as part of the wind-up and acceleration phases and wrist extension as part of the release). The 5-year old’s release could have been improved if he had kept the frisbee level.  Skilled ultimate frisbee players prefer to position the frisbee parallel to the ground in order to reduce unnecessary wobble and to make the flight path more predictable for a teammate.

(Word Count: 453)

[ri-disc-ulous-6-blog]

6-12 Year Old Participant

This section will be analyzing the throw of a 10-year-old female.  To understand the science behind her throw,  this section will be discussing the various factors that predispose a female of her age to throw in the manner that she has.  Firstly, it is important to keep in mind that girls tend to have more body fat and less muscle tissue than boys, and as such this could be the explanation as to why her throw is not nearly as powerful as a boy’s throw of the same age may be.  

As soon as humans reach their middle to late childhood (6-12 years of age), it is well known that strength, speed, large-muscle coordination and hand-eye coordination begin to improve (Boyd et al,. 2018).  At around this same age, fine motor coordination becomes much more skillful.  This improvement in fine-motor coordination can be attributed to the maturation of the wrist which is known to occur more rapidly in girls than in boys (Payne & Isaacs, 2017).  Therefore, though females can make more coordinated movements at this age, these movements tend to lack speed and strength.  

As the network of neural connections continues to expand throughout development, the sensory and motor areas of the brain are myelinated at an increasingly rapid rate.  The improvements that we see in fine motor skills, as well as coordination in the performance of motor skills by children of this age, can be attributed to this increased rate of myelinization.  

Throughout the course of childhood, bones continuously grow and change their composition.  This change can be linked to the improvements that can be seen in coordinated movement.  In particular, the bones of the wrist differentiate from one mass of cartilage into nine separate bones from birth continuing on into adolescence (Boyd et al., 2018).  In middle-late childhood, it can be said with confidence that the wrist is not as mature as it will eventually be.  In addition, it has been previously observed that the separation of these wrist bones appears earlier in females than males.  This then could be a reason as to why girls have an advantage in fine-motor skills at an earlier age.  

Another process that could explain the gap in coordinated movement is ossification.  The hardening of bone has previously been linked to many other milestones in motor development (Boyd et al., 2018).  Therefore, it is reasonable to believe that the same developmental explanation can be used in this scenario as well.  As such, the continuation of the process of ossification is likely contributing to the improvements seen in the frisbee throw in this age group.

Finally, a significant factor affecting her performance in throwing the frisbee is her arm length. Previous studies suggest that increased shoulder width, as well as arm length, in males are advantageous in helping males perform throwing tasks (Payne & Isaacs, 2017). All of these factors act on this child’s frisbee throw accordingly so that the final product is a relatively well-coordinated, but rather weak, execution of the movement.

(Word Count: 485)

[ri-disc-ulous-6-blog]

12-18 Year Old Participant

The participant performing the backhand frisbee throw (motor skill) is a 17-year-old male.

The participant places his thumb on top of the disc with the forefinger along the rim, using the rest of his fingers to balance the disc.  During the wind-up phase, the participant twists his trunk shifting his weight onto his left foot.  He horizontally adducts his arm towards his torso flexing his forearm and curling his wrist.  In the acceleration phase, his torso twists and weight shifts onto his right leg which is pointed in the direction of the desired throw.  His arm supinates as he is about to throw the disc.  His right arm and torso are aligned in the frontal plane as he extends his arm and perfectly times the wrist flick, throwing the frisbee.  This flick at the end of the motion is necessary for optimal accuracy and power.  In the follow-through phase, his arm continues to extend maximally even after the frisbee leaves his wrist.

When comparing motor skills with other age groups, there are significant differences in adolescents during this period.  Young people go through many physical changes in terms of muscular, skeletal and brain function.  The brain changes in different ways as there is an increase in the volume of grey matter (Boyd et al,. 2018).  Grey matter is seen to be important in areas where muscle control and decision making occurs.  Decision making is needed when performing motor skills and is overseen by the frontal lobe.  The primary motor cortex is important when it comes to muscle control, as this is the control center for complex actions.  The cerebellum is also very important as its role is to control balance, movement, and coordination of muscles.  There is also an increase in white matter in the corpus callosum which integrates activity between the left and right side of the brain (Boyd et al., 2018).  

When it comes to the muscle changes, adolescents undergo increased joint development which helps with increased coordination.  Adolescent muscle fibres also become thicker, denser, and much stronger when compared with other age groups (Boyd et al., 2018).  All these changes help the participant demonstrate an accurate frisbee throw when compared to the optimum technique.  The technique requires a lot of coordination between different muscle groups to perform the skill optimally.  

Therefore, the physical changes that the body undergoes during adolescence give this age group an advantage.  When compared to the younger models and older adult group, you can notice the difference in muscle coordination and control.  Full physical maturity is reached during the late adolescence stage (16-20 years) (Brown, Patel & Darmawan, 2017).  This could be the reason why this participant performs the skill optimally as he is right within the peak age group at 17 years old.

 (Word Count: 449)

[ri-disc-ulous-6-blog]

21 Year Old Participant 

This frisbee throw was completed by a 21-year-old male. The participant begins with a fixed grip on the disc with his thumb on top of the frisbee, his index finger along the edge, and the remaining fingers tucked neatly underneath the lip of the disc.  His feet are firmly planted in a wide stance for balance and he bends his knees slightly as he medially rotates his torso and adducts and flexes his throwing arm into the “cocked” position to store potential energy.  As he executes the throw, he begins to abduct and extend his throwing arm while leaning forward slightly; this brings his center of mass forward to generate extra power.

Throughout the throw, his feet stay planted and do not move.  He keeps the frisbee level on the horizontal plane, at around the abdominal level, which is optimal for a level throw.

As visible in the anterior view of the execution, the participant releases the disk at a slight angle, causing the frisbee to curve to the participants right.  This is not the ideal technique, however, it can be attributed to a lack of practice, or a desire not to strike the cameraman, and not to cognitive or physical development.  The participant also demonstrates a full extension of the arm during the follow-through phase.

This age group is in an ideal cognitive and motor stage for physical movements.  Young adults in their 20s and 30s have more muscle tissue, higher bone density, more brain mass, better eyesight, hearing, and ventilatory capacity (Boyd, Johnson & Bee, 2018), and cognitive performance is at its peak (Allen & Hopkins, 2015).  The brains of young adults settle into a stable size and weight, and brain functions become localize to specific regions of the brain (Gaillard et al., 2000).

Each of these advantages allows the participant to effectively complete the steps of the throw; overall this participant demonstrates a proficient execution of the 3 stages of throwing a frisbee with very few deviations from the ideal technique.  This age group can be considered the best suited to complete this activity successfully.

(Word Count: 341)

[ri-disc-ulous-6-blog]

60+ Year Old Participant

The older adult Frisbee throw was completed by a 68-year-old participant.

This participant demonstrates a passable technique for throwing the Frisbee, however significant deviation from the optimal technique, due to old age, can be observed.

He starts with a proficient backhand grip on the Frisbee (Solomon, Banerjee, Horn, 2013).  The participant begins to execute an appropriate wind-up with his feet firmly planted and completing a horizontal abduction and flexion of the throwing arm to bring the Frisbee into the “cocked” position, as well as rotating the torso medially to further increase stored potential kinetic energy (2013). At this age, there is a reduction in the volume of grey matter in the brain, which results in a decrease in the density of dendrites and consequently affects balance and coordination due to decrease nerve conduction speed (Boyd et al., 2018). This effect becomes apparent during the acceleration and follow-through phase.

As the participant prepares to throw the Frisbee he takes a half step forward to begin shifting his body weight into the throw. As he begins the throw, he rotates his torso laterally and opens his hips as he abducts and extends his throwing arm while shifting his body weight forward onto his anterior foot (Solomon et al,. 2013).

While the participant may have displayed the correct sequence of throwing a Frisbee from the “cocked position”, he demonstrates a significant deviation from the horizontal plane on which the throw should be executed. He initially lowers the Frisbee to his waist level and then raises the arm superiorly to his shoulder level prior to the release, the action is similar to that of a “U” shape. This is done to make up for a lack of power and rotational torque due to an age-related decrease in muscle size, fibre strength, and a loss of type 2 fibres (Boyd et al., 2018). These neural and muscular factors contributing to general slowness consequently causes a poor angle of delivery at the release; the Frisbee has an anterior tilt upon release (nose down) and a low RPM which contribute greatly to instability and deviation from the intended path (Solomon et al,. 2013).

It is evident that the lack of power and rotation on release, combined with the deviations from the horizontal and mediolateral planes and a late release cause the frisbee to wobble greatly in the air, and fly far off to the participants right.

Following the throw, the participant demonstrates a decent follow through, however, has some difficulty keeping his balance as he has to bring his posterior foot forward. This is due to the aforementioned degradation of grey matter in the brain (Boyd et al,. 2018).

Overall, this participant demonstrates the correct sequencing of steps to throw a Frisbee. Some key constraints affect this participant’s ability to follow the optimal techniques of throwing a frisbee such as decreased muscle size, strength, power, and elasticity, decreased nerve conduction speed, and sarcopenia due to old age (Schaie & Wiliis, 2005).

(Word Count: 374)

[ri-disc-ulous-6-blog]

Conclusion

In synopsis, the participant for each age group demonstrated considerably different backhand frisbee throw techniques.  The biomechanical differences observed were consistent with our expectations for each age group based on their respective stages of development.  The participants from the adolescent and early adulthood age categories were far more skilled, as would be expected since these groups are nearing their peak for physical and cognitive development.  The biggest differentiator between the skilled and unskilled was that the skilled were able to sequence their torsos, shoulder, elbow and wrist movements in a fluid matter.  

Older adults lose some neuromuscular coordination and strength due to their age and thus are restricted from performing the movement optimally.  Children between 2 and 12 years of age are either undeveloped in terms of coordination and motor skill development or are too young to have cognitively laid out the discrete actions in order to carry out this sequential movement.  The underlying reasons for the submaximal performance of this motor skill could be attributed to functional differences such as wrist maturation, cognitive development, as well as arm length.  

The participant from the early adulthood group who performed the frisbee throw is arguably the best example of what this throw should ideally look like.  At the age of 19, human wrist bones have differentiated in order to allow for incredibly fine motor coordination.  As well, the localization of specialized brain functions is responsible for aiding in proper motor mapping of the skill being performed.  Finally, as mentioned previously, increased shoulder width and arm length are favourable for performing proper throwing techniques.  That being said, early adulthood is a stage of development when the bones have all properly developed and grown as to reach their optimal measurements.  

In regards to the late adulthood group, participants of this age have begun to undergo the process of bone density loss at a higher rate than any other age group. Additionally, nerve conduction speed is much lower than the other groups as there is a loss of myelination that occurs with age.  Finally, a decrease in muscle size and fiber types is responsible for the lack of strength observed in this participant as this is a common occurrence with people in the stages of late adulthood.  

Participants from the early and late childhood group can be characterized as having similar throws to that of persons in the late adulthood group.  However, children have not yet mastered certain motor skills due to developmental restrictions, participants in the stages of late adulthood have exceeded their peak development and have begun deteriorating in areas such as their bones, muscles, and cognition.

(Word Count: 435)

[ri-disc-ulous-6-blog]

References

Allen, S. V., & Hopkins, W. G. (2015). Age of Peak Competitive Performance of Elite Athletes: A Systematic Review. Sports Medicine, 45(10), 1431-1441.

Boyd, D. R., Johnson, P., & Bee, H. L. (2018). Lifespan development (6th ed). Boston: Pearson.

Brown, K. A., Patel, D. R., & Darmawan, D. (2017). Participation in sports in relation to adolescent growth and development. Translational pediatrics, 6(3), 150–159.

Gaillard, W., Hertz-Pannier., Mott, S., Barnett, A., LeBihan, D., & Theodore, W. (2000). Functional anatomy of cognitive development: fMRI of verbal fluency in children and adults. Neurology, 54, 180-185

Freitas, D. L., Lausen, B., Maia, J. A., Gouveia, É R., Antunes, A. M., Thomis, M., . . . Malina, R. M. (2018). Skeletal maturation, fundamental motor skills, and motor performance in preschool children. Scandinavian Journal of Medicine & Science in Sports, 28(11), 2358-2368.

Payne, V. G., & Isaacs, L. D. (2017). Human motor development: A lifespan approach (9th ed.). London: Routledge.

Schaie, K.W., & Willis , S.L. (2005). Mind alert: Intellectual functioning in adulthood: Growth, maintenance, decline, and modifiability. Lecture presented at the Joint Conference of the American Society on Aging and the National Council on Aging as part of the Mind-Alert Program.

Solomon, C., Banerjee, A., & Horn, M. S. (2013). Ultimate trainer. Proceedings of the 8th International Conference on Tangible, Embedded and Embodied Interaction - TEI 14.

Wulf, G. (2007). Attention and motor skill learning. Leeds: Human Kinetics.