PhD, Associate Professor A.A. Jalilov¹
Dr.Hab. V.F. Balashova^1
1Togliatti State University, Russia

Keywords: low-kick techniques in kickboxing, bio-kinematic elementary chain stiffness control, joint stiffness control mechanism.

Background. Analyses of the modern theories and competitive practices show that low-kick technique as an integral part of the kicking skills in kickboxing is still underexplored by the modern biomechanical tools.

Objective of the study was to improve the traditional low-kick technique applied in modern kickboxing based on an analysis of the bio-kinematic elementary chain stiffness control biomechanics.

Methods and structure of the study. The study of the bio-kinematic elementary chain stiffness control model in the low-kick kickboxing technique was designed to include the following experiment. The subjects performed standing test low kicks with the following sets: (1) proactive set dominated by a reactive power creation action; (2) tightening kick sequence with the muscle stiffing action geared to fast transfer the energy impulse from one element to the other in the movement sequence; and (3) rated-power kicks i.e. driven by the muscular stiffness control action.

The bio-kinematic elementary chain stiffness control biomechanics was studied on an ankle joint model with the accelerations of the thigh mass, shin mass and foot mass centres travels being registered in sagittal planes. In addition, two accelerometers were fixed on the ankle joints of the subjects. The tests were designed to simultaneously read strain dynamograms of the subject’s reciprocating actions with space, time and dynamometric tags.

The acceleration profiling diagrams of the test set kicks substantiated the theoretical bio-kinematic elementary chain stiffness control model in application to the low-kick sequences. To obtain further evidence of the bio-kinematic elementary chain stiffness control in the low-kick sequence being secured by the antagonistic muscles, we performed an experiment to read the bio-currents of the ankle joint muscles acting in the low-kick sequence. The bio-currents in musculus tibialis anterior and medial heads of the shin musculus gastrocnemius and musculus salens in the test set kicks were indicative of the simultaneous activation of the antagonistic muscles in the low-kick sequences. The digital test data were printed out on the punch-tape by a start-stop telegraph system followed by a computer data processing using a standard application software.

Subject to the education process tests under the study (in September 2015 and March 2016) were 36 highly-skilled kickboxers including 6 Masters of Sports of Russia; 14 Candidate Masters of Sports and 18 Class I Athletes trained at Boyevye Perchatki [Combat Gloves] Club in Togliatti.

Study results and discussion. Generally the kicking techniques applied in the modern kickboxing sport may be described as composed of rotating and reciprocating elementary actions. Tests showed that the muscle electrical activity in the combined reciprocating and rotating kicking actions is higher than that in the reciprocating-rotary ones.

Furthermore, the summarised bio-currents in the musculus tibialis anterior and medial head of the shin musculus gastrocnemius in the combined reciprocating and rotating kicking action were tested higher in their amplitudes than those in the shin musculus salens; The situation was opposite in the real kick action that is indicative of more stiff fixation of the chain elements than in the fake action.

The kicking actions in kickboxing are driven both by common and specific action building mechanisms. Mentioned first among the common mechanisms should be the energy impulse (mЕ) transfer mechanism that conveys it from massive bodily elements to less massive ones and further to the target. We profiled accelerations of the bodily elements in the kicking sequence with the energy impulse going from the thigh to the shin i.e. from the most massive bodily element (that is the hip joint) to the less massive ankle joint in the mechanical motor sequence.

The energy transfer mechanism in a bio-system may vary depending on the kick timing. Let us consider the simplified action patterns of the low limb elementary bio-kinematic chain (thigh – shin – foot) with the variable time of the kicking action. Power kicks in bouts may be classified by the timing as follows: (a) when there is enough time to fully activate the elementary bodily chain acceleration mechanism to release an explosive kicking action; and (b) when the time is too short for the action of the above mechanism.

In case (a), the subject activates the energy transfer mechanism on a timely basis, with the low-kick technique being technically effective and tactically relevant. In case (b), when the time for a full-power kick is too short, the elementary bio-kinematic chain action may take one of the following two options.

Option one implies the natural kicking pace being forcefully stepped up so that the energy impulse is transferred via the chain elements at the speed higher than the natural acceleration rates. This option, however, is unfeasible in fact since the further acceleration of the bodily elements is only possible if the speed-strength qualities of the muscles are further increased. However, the modern kicking techniques applied by highly-skilled kickboxers are already performed at the upper limit of the natural human speed-strength abilities.

Option two of the kicking actions in a time shortage situation implies every next bodily element in the chain being mobilised for the action earlier, and this may be attained by the higher rotary stiffness in the acting joint secured by the antagonistic muscles. It should be noted that one or a few elements may be fixed in the kicking action simultaneously; hence, the kick action time may be varied by the bio-kinematic elements stiffness rates being changed in the low-kick action to control the action time.

Therefore, actually feasible are the following two extreme options of the bio-kinematic chain elements fixation control in the low-kick sequence. Option one implies every element of the bio-kinematic chain being firmly fixed, with the maximum gain in the action time – since it takes virtually no time to transfer the energy impulse from one element to another; albeit this option implies the highest speed loss for the final element (that is the shin). Option two requires no firm fixing of the chain elements, with the kicking wave going via thigh – shin – foot chain. The widest imaginable array of the bio-kinematic chain element fixation patterns falls in between the above two extreme options of the low-kick sequence. It should be noted that the shorter is the time for the kicking action allowed by the tactical situation the higher is the number of firmly fixed chain elements and/or the fixing power, with the growing proximal joint rotating force.

Our analysis of the muscular electrical activity in the low-kick action showed the following: activity in the musculus tibialis anterior and medial head of the shin musculus gastrocnemius are similar in the both above options – i.e. the activity first grows and then falls; versus the activity in the shin musculus salens that is very high at first and falls to zero prior to the kick. This effect may be due to the natural operation of the ankle joint with the muscles being flexed and extended to transfer the energy impulse from the thigh to the shin and then to the foot.

In the proactive low-kicking sequence, the antagonistic muscle activity is simultaneous i.e. grows and falls at the same time, with the muscles in the technique performance process working to secure due stiffness for the ankle joint at the kick moment. The flexion-extension movements in the ankle joint in the proactive low-kick sequence (essentially geared to increase the ankle stiffness) were also confirmed by goniographic profiles of the hip and ankle joint movements in the low-kick sequence.

Let us now apply the above experimental data to consider the time control process in the low-kicking action within the whole bio-kinematic chain. A kickboxer controls the action time by varying the elementary fixing strength rates in the bio-kinematic chain. The fixing stiffness control (muscular recuperation) skills geared to harmonically fix every bio-kinematic chain element in an offensive kicking sequence may be indirectly rated by metering the time phases of the kicking action.

The kick action profiling data generated by the tests showed the tested subjects being skilful in controlling the bio-kinematic chain elementary stiffness rates in the low-kick actions (P < 0.001) versus the reference (non-sporting) group tested unskilful in this aspect. Thus some of the reference group subjects were found completely unable to properly time and control the kicking action on the whole and the bio-kinematic chain elementary stiffness rates in particular.

The experimental data on the body elements being fixed in the low-kick sequence give grounds to state that the relevant biomechanical movement parameters are controlled not only within a single joint but within the whole bio-kinematic chain in the low-kicking action. The body elements control test rates of the sporting versus non-sporting subjects showed that the ability to control the bio-kinematic chain elementary stiffness rates in the low-kick action grows with training i.e. may be learnt.

Therefore, the study found that the low-kick actions in modern kickboxing are driven by the bio-kinematic chain elementary stiffness rates controlling mechanism. Particularly interesting in this context is the question of what the correlation of the joint stiffness control mechanism with the energy impulse transfer mechanism is that secures the energy wave flowing through the bio-system of bodily elements in the low-kicking action. To answer the question we need to address the following two aspects: theoretical one that refers to the correlations of both of the mechanisms in the specific low-kick action design aspect; and the practical one that refers to the interrelations of both of the mechanisms in their progress i.e. imagine the ideal system to ensure them being efficiently developed in the kicking actions mastering process.

The bio-kinematic chain elementary stiffness rates control mechanism is critical for the process timing and the energy impulse transfer patterns within the range of the above two extreme options. A primary role needs to be given to the energy impulse transfer mechanism for the reason that the elements fixation stiffness rates may be controlled only when the biomechanical frame of the kicking techniques (with the movements being designed within the range of the above two extreme options to attain the maximal speeds of the kicking actions) is already established.

The joint stiffness control mechanism may be described as a more general one, whilst the energy impulse transfer mechanism may be viewed as its particular case i.e. the extreme version. Both of the mechanisms are interrelated in the low-kick technique mastering process – in the sense that the trainee who has mastered the bio-kinematic elementary chain fixing skills is fully able to mobilise the energy impulse transfer mechanism for the low-kick (thigh – shin) being efficient. However, the one who is skilful enough in the energy impulse transfer from one bodily chain element to the other is not necessarily skilful in controlling the bio-kinematic chain element fixation stiffness; these skills need to be developed in the low-kick technique mastering process with the elements of the bio-kinematic chain being intuitively fixed in the chain even in unexpected fight situations. It should also be mentioned that the individual low-kick technique mastering process may be improved by the trainee being duly motivated for the kicking actions.

Conclusion. The study found that the biomechanical parameters are controlled not only within a single joint, but also within the whole bio-kinematic chain of bodily elements. The bodily elementary stiffness rate control tests of the sporting versus non-sporting subjects generated by the study showed that the ability to control the bio-kinematic chain elementary stiffness rates in the low-kick actions grows with training i.e. may be learnt.

References

1. Atilov A.A., Glebov E.I. Kikboksing, lou-kik [Kickboxing, low kick technique]. Rostov-on-Don, 2002, 320 p.
2. Donskoy D.D., Zatsiorskiy V.M. Biomekhanika. Uch. dlya inst-ov fizicheskoy kultury [Biomechanics. Textbook for institutes of physical culture]. Moscow: Fizicheskaya kultura i sport publ., 1982, 263 p.
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4. Jalilov A.A., Balashova V.F. Biomekhanicheskie kharakteristiki napadayushchego udara v kikboksinge [Biomechanical characteristics of kickboxing offensive technique]. Teoriya i praktika fiz. kultury, no. 2, 2016, pp. 15-17.
5. Zatsiorskiy V.M. Sportivnaya metrologiya. Uch. dlya inst-ov fizicheskoy kultury [Sports metrology. Textbook for institutes of physical culture]. Moscow: Fizicheskaya kultura i sport publ., 1982, 252 p.

Corresponding author: alim-tlt63@yandex.ru

Abstract         

The article analyses some deficiencies of the ongoing research of the low-kick techniques in the modern kickboxing sport due to the still underdeveloped biomechanical approach to the bio-kinematic elementary chain structure analysis. The traditional coaching practices tend to neglect the structures and forms of the trainee’s bodily elements being considered from a biomechanical viewpoint and, as a result, the mastered techniques are often incompliant with the relevant biomechanical model characteristics and genuine logics of the motor skill biomechanics. As a result, they often fail to build the required habitual skill structure (muscle sense) to control the energy impulse flow from one bodily element to another in the low-kick movement sequence. The authors consider in detail the interactions of the joint stiffness control mechanisms with the kinetic momentum (energy) transfer mechanism in the low-kicking movement sequences to profile the bio-kinematic elementary chain stiffness control process in the low-kick techniques. The study data and analyses demonstrate that the low-kick movement sequence is secured by the bio-kinematic chain elements (joints) being fixed by the antagonistic muscle groups; with a special emphasis made on the biomechanical aspects of the kinetic energy transfer mechanism in the low-kick movement sequences.