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Introduction

      Motor development concentrates on the changes in movement behavior to acquire locomotor skills. Jumping occurs when “individuals propel their bodies from a surface with either one or both feet, and land with both feet” (Haywood & Getchell, 2014, p. 136). For the purpose of this motor skill analysis and developmental comparison, the standing long jump will be examined in detail. The standing long jump is a two-foot jump used to propel an individual horizontally as far as possible. The purpose of this skill is to test explosive leg power using maximum muscle forces in a short period of time. The outcome of the skill is measured in terms of distance from the point of takeoff to the nearest point of contact on landing (Wood, 2008). The jump can be broken down into four distinct phases: preparatory, takeoff, flight, and landing. The preparatory phase involves transitioning from a static stance position to a crouched position, generating strong enough forces to initiate takeoff. The takeoff phase occurs when the jumper pushes off the ground with forces directed downwards and backwards to propel their body into the air. Throughout the flight phase, the arms, legs, and trunk adjust to prepare for contact with the ground. The landing phase follows as both feet make contact with the ground and the jumper adjusts their center of gravity to maintain balance and absorb landing forces (Hraski, Hraski, & Prskalo, 2015).

      The standing long jump is a complex motor skill that demands coordination and timing of body segments to achieve a successful jump (Sgrò et al., 2017). Jumping is a difficult motor skill to develop since individuals must obtain the strength to launch their bodies into the air. The jump requires neuromuscular control in regulating sufficient leg patterns, limb positions, and movement speeds (Haywood & Getchell, 2014). The progression of development depends on the interaction of individual, environmental, and task constraints associated with Newell��s Model (Newell, 1986). Notable constraints may include: physical and mental characteristics, structural and functional limitations, external properties of the environment, and sociocultural factors. Therefore, the developmental changes correlated with age will play a role in the overall execution of the skill (Liardi, 2017).

      While research has identified that performance differences are partially age-related, no differences associated with gender have been proposed (Clark, Phillips, & Petersen, 1989; Nikolić, Mraković, & Horvat, 2013). Following periods of non-use, research has determined there are no significant declines in the level of performance of the jump (Haywood & Getchell, 2014). Despite this aspect of continuity, the execution of the jump is moderated by individual variability, the age at which particular skills emerge, differential rates of development, and diverse patterns of maturation (Liardi, 2017). The following videos will analyze the age-related changes concerning the qualitative movement patterns of the standing long jump.  

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Early Childhood (2-6): Sally, Age 5

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Early Childhood (2-6): Sally, Age 5

      Typically by school age, children are able to perform a wide variety of jumps involving difficult movement patterns, such as alternating feet and jumping over objects (Haywood & Getchell, 2014). When looking at Sally’s movement sequences while performing the standing long jump, we can see Sally performs a highly skilled jump for her age. She begins her preparatory phase with her arms extended together, and her hips and knees fully flexed to a crouched position before takeoff. At this age, Sally’s muscles are still developing and hypertrophy will continue until she is about 13 years old. However, knowing that the distribution of muscle fibre type is complete by the age of one, we postulate that Sally has an abundance of fast-twitch muscle fibres and enough leg strength to be able to propel her body into the air following this deep crouch (Liardi, 2017).

      Sally’s takeoff is initiated with both feet leaving the ground simultaneously, however, her legs do not reach full extension. This aspect is not indicative of advanced development, as both hip and knee extension are primary requirements for proficient jumping (Liardi, 2017). On the other hand, Sally does show proficient jumping as her heels lift off the ground before her knees extend. Sally’s arms extend out vigorously in a forward and upward fashion, reaching full extension overhead. However, there is a caveat present here. With Sally’s arms failing to rise symmetrically, her right arm extends slightly higher than her left arm, possibly indicating her underdeveloped neuromuscular coordination.

      During flight, Sally’s hips and knees flex in a synchronous manner, with her trunk flexed at approximately 30 degrees, and her arms assuming high to middle guard. Upon landing, Sally’s arms extend down and to the side, acting as brakes to stop the momentum of her trunk. This facet is indicative of a beginner level jump seen during the motor development of early childhood. Sally also loses her balance after landing, as she takes an extra step forward with her right foot followed by her left foot. This loss of balance is not characteristic of a proficient standing long jump (Haywood & Getchell, 2014). Additional research has noted that skillful execution of the standing long jump may not be observed before the age of six due to the difficulty of controlling one’s center of gravity upon contact. This evidence suggests that Sally’s lack of successful performance during her landing phase may be expected for a five year old who is unable to maintain sufficient balance (Sgrò et al., 2017).

      Overall, Sally’s jump contrasts the performance of other individuals of the same age. Research has found that by the age of three, children demonstrate the most immature form of the standing long jump. The age of nine is typically when children are able to display the most mature form of the jump. However, Sally has demonstrated movement patterns beyond these age-related expectations (Clark, Phillips, & Petersen, 1989). This may be the result of her athletic abilities and rearing environment to partake in physical activity.

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Later Childhood (7-12): Lisa, Age 10

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Later Childhood (7-12): Lisa, Age 10

      After observing Lisa’s standing long jump performance, it is possible to note her individualized movement patterns. While it may be expected that Lisa would display a more skillful execution compared to Sally based on age alone, we found this was not the case. At first glance, it appears that Lisa exerts more explosive leg power and achieves a further jumping distance than Sally. But after further analyzing Lisa’s jumping sequence, we can see that she does not acquire the characteristics of proficient jumping to the same extent as Sally (Haywood & Getchell, 2014).

      Although Lisa does display an advanced level crouch as she flexes prior to takeoff, her arms show very little extension compared to Sally. Lisa executes overhead arm flexion and she leaves the ground with both feet, displaying a slight tip forward as her whole body extends. Unlike Sally, Lisa’s heels do not lift off the ground first, but rather simultaneously as her knees extend. We estimate Lisa demonstrates this slower rate of development because she may not have the neuromuscular coordination to initiate the appropriate timing of these movements to take full advantage of Newton’s third law (Liardi, 2017).

      During flight, Lisa’s trunk is erect and her back exhibits slight hyperextension. She does not display hip or knee flexion as she swings her fully extended legs underneath her body. During later childhood, muscle mass is expected to increase in diameter and length by the addition of sarcomeres, and muscle fibre type is similar to adult distribution (Liardi, 2017). Although Lisa has the necessary muscular strength to propel her body into the air, she exhibits an altered rate of development and less proficient jumping compared to Sally. Thus, we suggest Lisa may have a smaller distribution of fast-twitch muscle fibres, displaying her lack of neuromuscular speed and coordination to perform proficient leg and trunk positioning (Haywood & Getchell, 2014).

      In preparation for landing, Lisa’s arms lower to middle guard and her legs are extended. She lands simultaneously on both feet, her trunk flexes, and her arms act as brakes to stop the momentum of her trunk, very similar to Sally. Her knees flex to less than 90 degrees, positioning her thighs less than parallel to the floor. With the exception of her third jump, when Lisa flexes on landing, her center of gravity is close to her base of support and slightly transitions ahead of her feet. This landing sequence is the most notable age-related change between Sally and Lisa. Lisa’s more advanced landing indicates her ability to maximize the principles of balance and stability by maintaining a wider base of support and lower center of gravity. We can note the increased development of Lisa’s muscular system and her ability to attend to sensory information, such as using spatial awareness cues during landing. Subsequently, Lisa shows improved balance during a developmental stage where her body is continually growing in response to her individual physiology, personal experiences, and her unique environment (Liardi, 2017).

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Adolescence (13-18): Abi, Age 15

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Adolescence (13-18): Abi, Age 15

      Following an increase in age, Abi demonstrates greater neuromuscular development, physiological maturity, balance, coordination, and leg strength compared to Lisa. This conclusion was made based on Abi’s ability to successfully demonstrate almost all of the criteria of a proficient standing long jump (Haywood & Getchell, 2014; Nikolić et al., 2013). Abi initiates her preparatory jump with a deep crouch, flexing at the hips, knees, and ankles. Her arms flex forward while her upper trunk is also tipped forward. Abi then swings her arms back, her trunk tips further forward, and her knee crouch increases. Typically, adolescent girls’ muscle mass is fully developed by the age of 13, they have achieved peak height and weight velocities, and relative growth begins to taper off throughout puberty and maturation (Liardi, 2017). We estimate that these age-related changes afford Abi the ability to maximize her body positioning and muscle forces. Thus, she exerts powerful takeoff forces by recruiting more muscle units, resulting from experience and repetition.

      At takeoff, Abi’s arms vigorously extend symmetrically forward and upward. Her heels leave the ground and then her legs fully extend, pushing off the ground with both feet. During flight, Abi’s arms reach overhead, her knee flexion leads to hip flexion, and her trunk remains flexed at 30 degrees. With hip flexion, she moves her body into a jackknife position, but her thighs are not fully parallel to the floor. This is the only pattern of proficient jumping that Abi does not fully demonstrate. Her inability to demonstrate this technique for all three jumps may be due to her environmental constraints and her individual effort put into performing the jump, unrelated to her skill level. We believe that Abi has the strength and neuromuscular capability to demonstrate parallel thighs to the floor, but she may have saved her energy and maximum muscle forces to avoid landing too hard on the hardwood floor. Therefore, Abi’s lack of proficient movement may be attributed to other confounding variables, not a result of altered development. We speculate that if Abi was in an environment where she had an audience and she was expected to perform her furthest jump, she would have achieved this proficient jumping aspect.

      Upon landing, Abi’s arms move downwards into middle guard to keep her balance, as her knees extend and swing forward for a two-foot landing. Her ankles and legs flex with her thighs parallel to the floor in order to absorb the shock of the landing. Gallahue (2012) describes a proficient jumper as someone who is mechanically efficient, coordinated, and controlled. This is descriptive of Abi’s performance. By adolescence, we can see the age-related changes from later childhood as Abi has developed the necessary jumping skills to a much further degree than Lisa. Abi can effectively maneuver her body, activate the appropriate muscles, accommodate for constraints, and maintain her stability-mobility trade off (Liardi, 2017).

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Older Adulthood (60+): Linda, Age 65

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Older Adulthood (60+): Linda, Age 65

        The standing long jump performance of older adults is expected to correlate with the deterioration of the aging process. After viewing Linda’s jumping sequences, we can see that she does not perform a proficient jump. Linda uses techniques to maintain stability, rather than gain mobility (Liardi, 2017). Linda begins the preparatory phase in a crouched position with her knees and hips partially flexed. Her arms are flexed forward and her upper trunk is also tipped forward. Prior to takeoff, her arms swing back but she does not bend into a deeper crouch. This results in minimal momentum and takeoff forces to propel herself off the ground. This is not indicative of a proficient jump when compared to Abi’s performance.

        At takeoff, Linda’s arms swing forward and her heels, knees, and hips extend simultaneously. However, her knees and hips do not complete full extension as she leaves the ground with two feet. In older adulthood, muscle mass declines are significant after the age of 50 with losses occurring in number and size. Leg strength declines at about 3% per year beginning at the age of 65. Due to these age-related changes, Linda’s decreased muscle fibre quality may cause her to exhibit reduced force production and a lack of proficient muscle actions (Liardi, 2017).  

        During flight, Linda’s arms are at head level and wing out in attempts to maintain balance. Linda does not show the proficient skills of full flexion or parallel thighs to the floor, as her legs remain partially extended. Her legs swing forward and her arms are at middle guard. With aging, the musculoskeletal system is prone to deterioration as bone mass decreases at a rate of 1% per year beginning around the age of 20. Thus, we expect this factor to significantly affect Linda at the age of 65, resulting in more brittle bones (Liardi, 2017). Thereby, Linda’s regression causes her to favour stability and balance over speed and mobility.

        During landing, Linda flexes her knees and hips to absorb the contact forces. However, her thighs are not parallel to the floor, indicating the skill level of an inefficient jumper. She completes a two-foot landing with her trunk tipped forward and her center of gravity inline with her base of support. Her arms remain in middle guard to maintain balance and stability. Evidently, we can see the implications of the aging process following Abi’s youthful performance. In older adults, there is a delay in neural networking, a loss of motor unit recruitment, rigid body positioning, and joint stiffness (Liardi, 2017). We noted that Linda suffers from degeneration of cartilage in her right knee, possibly indicating decreases in elastin. In the frontal view, we can see Linda’s right knee collapses and she puts more weight onto her left leg. Resultantly, Linda shows decreased flexibility, which may explain why she does not complete full knee flexion or extension. With this in mind, Linda was told not over exert herself to avoid any injuries. Perhaps Linda’s full exertion may have resulted in increased jumping proficiency.

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Conclusion

     In conclusion, the standing long jump follows a similar pattern of development as other basic locomotor skills. The expected progression demonstrates ineffective jumping sequences during early childhood, to more competent jumping patterns in later childhood, to peak performance in adolescence, and eventually to declines in older adulthood. Performance advancements that take place typically demonstrate the adoption of movements to maximize the principles of motion (Haywood & Getchell, 2014). In our analysis of the standing long jump, we observed some differential results with respect to age-related stages of development. In early childhood, Sally outperformed the normative expectations of jumping development for most 2-6 year olds. While some of Sally’s techniques were still underdeveloped, her overall performance was more similar to that of adolescence as opposed to later childhood or older adulthood. In later childhood, Lisa did not meet the overall expectations of her age bracket for children ages 7-12. While only showing small improvements compared to Sally, Lisa’s performance was similar to that of older adulthood and contrasted adolescent proficiency. In adolescence, Abi demonstrated the most proficient jump as to be expected in youth ages 13-18. Her highly skilled performance directly contrasted all other age brackets. In older adulthood, Linda also demonstrated the normative expectations associated with those ages 65+. Linda’s performance was more similar to the inefficient sequences taking place during early and later childhood, and it contrasted that of adolescence.

     Following our comparison of the standing long jump, we were able analyze the movements taking place, establishing a better idea about how development is anticipated to emerge. Each individual can be described using Newell’s Model of Constraints to explain the differences in development across the lifespan (Newell, 1986). One individual constraint that functions as the most significant rate limiter within jumping performance is leg strength (Liardi, 2017). Typically, the development of the musculoskeletal system lacks complete strength from early to later childhood, which was seen in Sally and Lisa’s performance. In contrast, this limitation did not occur during Abi’s adolescent performance because she has essentially developed her complete muscular strength. In older adulthood, we concluded similar results to what was expected of the aging process. Linda showed regression in muscular strength, resembling inefficient and submaximal muscle forces comparable to the undeveloped systems of Sally and Lisa.

     While the outcome of each jump was not measured objectively in terms of distance, our observations and comparisons of qualitative movement patterns enabled us to recognize the age-related changes of motor development. When taking these results into consideration, it is important to recognize the paradox of motor development. While universality shows that individuals exhibit great similarity and generalized patterns of development, variability deems that individual differences do exist (Liardi, 2017). Therefore, as shown in our analysis, these individuals display their own unique patterns of standing long jump performances. 

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References

Clark, J.E., Phillips, S.J., & Petersen, R. (1989). Developmental stability in           jumping. Developmental Psychology, 25(6), 929-935. doi:10.1037/0012-1649.25.6.929

Gallahue, D., & Ozmun, J., Goodway, J. (2012). Understanding motor development: Infants, children, adolescents, adults (7th ed.). New York: McGraw Hill.

Haywood, K.M., & Getchell, N. (2014). Life span motor development (6th ed.). Champaign, IL: Human Kinetics.

Hraski, M., Hraski, Z., & Prskalo, I. (2015). Comparison of standing long jump technique performed by subjects from different age groups. Baltic Journal of Sport and Health Sciences, 98(3), 2-12.

Liardi, V. (2017). Chapter 1: Life span motor development: Fundamental concepts. [PowerPointSlides].

Liardi, V. (2017). Chapter 3: Principles of motion and stability. [PowerPoint Slides].

Liardi, V. (2017). Chapter 4: Physical growth, maturation and aging. [PowerPoint Slides].

Liardi, V. (2017). Chapter 5: Development and aging of body systems. [PowerPoint Slides].

Liardi, V. (2017). Chapter 7: Development of human locomotion. [PowerPoint Slides].

Newell, K.M. (1986). Constraints on the development of coordination. In M.G. Wade & H.T.A Whiting (Eds.), Motor development in children: Aspects of coordination and control (pp. 341-361). Amsterdam: Martinus Nijhoff Publishers.

Nikolić, I., Mraković, S., & Horvat, V. (2013). Standing long jump performance quality: Age and gender differences. Croatian Journal of Education, 15(1), 173-183.

Sgrò, F., Mango, P., Pignato, S., Schembri, R., Licari, D., & Lipoma, M. (2017).   Assessing standing long jump developmental levels using an inertial measurement unit. Perceptual and Motor Skills, 124(1), 21-38. doi:10.1177/0031512516682649

Wood, R. (2008). Standing long jump test (broad jump). Topend Sports. Retrieved from http://www.topendsports.com/testing/tests/longjump.htm