Course:KIN366/ConceptLibrary/Hopping
| Hopping | |
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| KIN 366 | |
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| Instructor: | Dr. Shannon S.D. Bredin |
| Email: | shannon.bredin@ubc.ca |
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| Course Discussion | |
Human hopping is a form of upright and bipedal locomotion, used for transportation or for recreation. This form of locomotion usually involves taking off and landing on the same leg either once, or repeatedly. The use of hopping first emerges during the developmental stages of children’s motor movements. Between the ages of 3 and 5 years old, children move through a series of stages to master this form of locomotion and fully acquire the skill of hopping.
Developmental Sequence for Hopping
When a child is in the process of learning to hop, the different progressions that lead up to the final skill can be divided up into different stages; the stages being different for legs and arms.
Leg Action
Specifically focusing on the movement of the lower limbs, the four stages that lead to proper hopping are momentary flight, fall and catch, projected takeoff, and projection delay [1].
- Momentary Flight: The knee and hip of the support leg (the leg that the individual is standing on) flex, which pulls the foot from the floor. The swing leg (the leg that does not have contact with the ground) is bent and lifted to the side or in front of the body, which is held in an inactive position. During this stage, very few hops can be achieved.
- Fall and Catch: The swing leg remains the same as the previous stage (momentary flight). The body leans slightly forward which allows for a minimal increase in leg extension creating a fall and catch effect where the support leg extends pushing the body up and forwards, then landing and catching the body. At this stage, the individual should be able to perform multiple hops.
- Projected Takeoff: The support leg produces extension in the hip, knee, and ankle prior to takeoff. The swing leg now assists in the hop with a pump up and down to aid in projection however the swing leg will not produce enough range to swing behind the support leg throughout the hop.
- Projection Delay: The swing leg now leads the motion of the hop moving from behind the support leg to in front of the support leg with and upward forward motion involving the pumping action. As the swing leg is moving forwards, the weight of the individual transfers along the foot to the ball, leading to the extension of the hip, knee, and ankle.
Arm Action
Specifically focusing on the movement of the upper limbs, the five stages that lead to proper hopping are bilateral inactive, bilateral reactive, bilateral assist, semi-opposition, and opposing assist [1].
- Bilateral Inactive:The arms are held in a static position throughout the hop and any movement that occurs is usually slight and unrelated to the hop.
- Bilateral Reactive: Prior to the take off, the arms shoot outward and rotate medially in a flapping motion in reaction to the loss of balance.
- Bilateral Assist: The arms pump up and down in a flapping motion slightly in front of the trunk of the body. Any downward and backward motions usually occur post-takeoff.
- Semi-opposition: The arm opposite the swing leg swings forwards as the leg moves forwards, and then the arm continues to swing back as the leg moves downwards. The arm opposite the support leg is variable and does not offer anything advantageous to the movement.
- Opposing Assist: The arm opposite the swing leg moves simultaneously forward and upward with the swing leg. The arm opposite the support leg moves in opposition with the swing leg, which contributes to balance and stability during the hop.
Developmental Stages in Hopping
Typically the initial stages of hopping do not occur before the age of 3 years old. These skills usually start to develop during the ages of 4 and 5 (also referred to as preschool years). At this age most children would fall into stage 2 of hopping and would continue to develop their skill past the age of 5 [2]. Once the child gains more experience hopping, they start to become a more proficient hopper, which is indicated by the force and stiffness of their landing in hopping [3] : [4]. For example, a novice hopper will land with a flat foot, holding the swing leg in a static position whereas a proficient hopper will be able to land softer by allowing a certain degree of flexion during landing to absorb some of the pressure as well as have the swing leg behind the support leg in order to prepare for the next hop. Tools: Some tools to help develop hopping in children would be things such as a hopscotch mat or blocks of different heights and surface stiffness. This would allow for children to increase the amount of practice they are able to obtain with this form of locomotion as well as experience different situations in which they can utilize a hop.
Ankle Joint Stiffness
When humans hop either in place or forwards, they adjust leg stiffness to accommodate for changes in frequency or surface stiffness. The primary way in that this occurs is by modulating ankle stiffness [5]. In reference to the lower limb joints that contribute to the projection of the body (hip, knee, and ankle), they all undergo a certain degree of stiffness modulation however ankle stiffness is the main determinant of leg stiffness and balance in hopping [5]. These differences in stiffness of the joints are not so obvious when hopping at a preferred height however when required to perform maximum height hop, leg stiffness increased by twice the preferred height amount and the increase in ankle stiffness is more drastic.
Constraints and Rate Limiters
The ability to hop most likely depends on the body’s postural ability to balance on one limb for a succession of hops. If a child or individual does not have the strength within the muscles that account for postural control with in the upper body, trunk, and legs, then it will be difficult to complete a successful hop. Not only does the individual need enough strength to maintain postural control but also they need enough strength in order to project their body weight off the ground with one limb as well as be able to successfully land on the ground with one limb [6]. A very common constraint that occurs during the developmental stages is the increase in weight of the individual [2]. The increase in weight would increase the amount of strength and force production needed to utilize the swing leg as well as project the body and lift the support leg.
Teachers and Parents
Being able to assess a child or individual’s hopping patterns is important for teachers and parents in monitoring the proper acquisition of locomotive patterns. For novice observers this can be difficult however using a systematic pattern of observing the body parts one at a time (legs and arms) can make this process much easier. First look at the swing leg to see if it is active during the hop. If the swing leg is active, then classify if the motion is in a pumping pattern and if it moves past the support leg. Second, turn the attention to the support leg and classify if the leg goes through extension during takeoff and flexion during landing. These are indicators of a proficient hopper. Third, turn the attention to the arms during the hop. Categorize whether the arms are moving bilaterally or in opposition. These markers will allow an observer to place the individual in a stage of hopping development and be able to assess the skill level acquired thus far [2]. Being able to assess the stage of hopping that a child is at can assist in identifying children who are falling behind in the acquisition of motor skills resulting in having physical difficulties and it can also be indicative of children who have neuromuscular abnormalities.
References
- ↑ 1.0 1.1 Robertson, M. A., & Halverson, L. E. (1984). Developing Children-Their Changing Movement: A Guide for Teachers. Lea & Febiger.
- ↑ 2.0 2.1 2.2 Haywood, K., & Getchell, N. (2009). Life span motor development. Human Kinetics. Cite error: Invalid
<ref>tag; name "Haywood" defined multiple times with different content Cite error: Invalid<ref>tag; name "Haywood" defined multiple times with different content - ↑ Getchell, N., & Roberton, M. A. (1989). Whole body stiffness as a function of developmental level in children's hopping. Developmental psychology, 25(6), 920.
- ↑ Roberton, M. A., & Halverson, L. E. (1988). The development of locomotor coordination: Longitudinal change and invariance. Journal of motor behavior,20(3), 197-241.
- ↑ 5.0 5.1 Farley, C. T., & Morgenroth, D. C. (1999). Leg stiffness primarily depends on ankle stiffness during human hopping. Journal of biomechanics, 32(3), 267-273.
- ↑ Hobara, H., Kanosue, K., & Suzuki, S. (2007). Changes in muscle activity with increase in leg stiffness during hopping. Neuroscience letters, 418(1), 55-59.