Countermovement Jump vs. Squat Jump
- Vertical jump and its relevancy to sport.
Sporting activities or exercise which is highly graded usually they are faced with various decelerating and accelerating movements of the limb which often generate eccentric, concentric, and isokinetic muscular shrinkages. The assessment of the strength of the lower limbs is characterized by the vertical jumps which include the standing countermovement jump (CMJ) and the standing squat jump (SJ). Spirit tests together with jump tests have been in the past applied together to determine the power strength and the speed of athletes in various sporting activities (Fung, 2013)
Vertical jump, as defined by Romano et al, refers to a compilation of ballistic multi-joint actions where the muscle that is located around the hip joint, knee and ankle unison operate in order to generate configurations of movement. Some of the significant aspects the vertical jump includes
- Explosive motions from different positions
- The contribution of a segment to the production of force during the take-off or jump
- The organization of concentrated effort vertical jump motion
- Contributions of the trunk to standing vertical jump take-offs (Hay, 2018)
During the flight phase, the upper extremities have usually contributed a lot towards ensuring that there are safe landing and take-off.
- Different type of jumps
The different types of jumps include
Squart jump – in this kind of jump the athlete tends to be in a semi-squat position whereby the athlete will hold in this same position for a period of 3 seconds after which the athlete takes off
Countermovement jump – in this type of jump, the athlete begins at an upright position and thereafter initiate a movement in the downward direction after which the athlete takes an upward movement which eventually results into a take-off. The optimum height which is achieved in a vertical jump is major as a result of the implementation of a great countermovement prior to the movement in the upward direction. This motion is also related to the maximum force and the maximum positive power (Mow et al, 2005).
- How when countermovement jump, when compared to squat jump, will result in a higher vertical jump, when compared to a non-countermovement jump.
The standard jump can be well explained in terms of the countermovement restriction and the application of arm for the squat jump while for the countermovement jump, it is the application of the countermovement by the help of a double arm. And as a result of this, research documents that the arm swing largely promotes the kinetic energy which tentatively makes more dynamic motions hence enhancing the jump height. Besides, the action of the double arm enhances the jump height by a percentage of roughly 10 percent since their activity is almost nearly to the speed of the center of gravity of the body almost meant to take off (Nordic et al, 2011).
Nevertheless, Lees and Barton suggest that the action of the double arm offers approximately additional; 13 percentage of the overall peak vertical momentum which is quite of greater importance in that the swing arm ensures a value close to 9 percentage of the vertical; jump. The countermovement jump greatly relies on the contractile characteristics and capacities of the muscles which are involved directly in the reflex mechanisms and the movement of the structure which is pre-activated and which produces a considerate amount of elastic energy in the muscles.
When the concentric forces are acting, it is a requirement that the hip joints, knee and on the ankle should be greater than the original force which is needed for the execution of the squat jump. And, usually, the optimum height in the vertical jumps is achieved by the execution of the countermovement prior to the upward motion (White & Panjabi, 2010).
- The Stretch-Shortening Cycle (SSC).
The SSC can be defined as a rapid eccentric (stretch) muscle action, followed immediately by a concentric (shortening) muscle action. in regards to this, there is the eccentric utilization ratio which is defined as the ability of an athlete to improve the utilization of the stretching shortening cycle during a countermovement jump.this ratio can be of great help to a coach in order to determine the stretch-shortening ability of an athlete and then apply it in the testing of the training readiness and the track fatigue.
- other reasons why CMJ performs better than SJ in relation to the mechanical mechanisms and the neuromuscular actions include
- reflex contribution
- storage and re-utilization of elastic energy
- augmented force production and myogenic active state
- better potentiation of the neuromuscular system (White & Panjabi, 2010).
References
Fung, Y.C., 2013. Biomechanics: mechanical properties of living tissues. Springer Science & Business Media.
Hay, J., 2018. The biomechanics of sports techniques. Prentice-Hall.
Mow, V.C., and Huiskes, R. eds., 2005. Basic orthopedic biomechanics & mechano-biology. Lippincott Williams & Wilkins.
Nordin, M. and Frankel, V.H. eds., 2011. Basic biomechanics of the musculoskeletal system. Lippincott Williams & Wilkins.
White, A.A. and Panjabi, M.M., 2010. Clinical biomechanics of the spine (Vol. 2, pp. 108-112). Philadelphia: Lippincott.
Winter, D.A., 2016. Biomechanics and motor control of human gait: normal, elderly and pathological.
Winter, D.A., 2009. Biomechanics and motor control of human movement. John Wiley & Sons.
Zajac, F.E., 2016. Muscle and tendon: properties, models, scaling, and application to biomechanics and motor control. Critical reviews in biomedical engineering, 17(4), pp.359-411.
