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15WAYS OF ENHANCEMENT OF EFFICIENT MOTOR ACTIONS IN THE FINAL PHASE OF IMPACT ACTION OF QUALIFIED BOXERS S.N. Neupokoev
L.V. Kapilevich, professor, Dr.Med. N.Z. Pavlov
National research Tomsk state university, Tomsk National research Tomsk polytechnic university, Tomsk
Key words: boxing, biomechanics, stabilography, stability.
Introduction. In the analysis of the existing methodology of improvement of effective punches we faced the problems of developing practical methods of mastering techniques of athletes' impact actions based on biomechanical laws [2, 6]. On the one hand, a significant place in the biomechanics of impact actions is taken by the problems related to the study of sports instruments, which are intermediate regulators and significantly affect the quality of movement control. On the other hand, the limited use of equipment to improve the impact action in boxing was noted, along with their negative impact on health and physical working capacity of athletes, in particular regular pain from punches when working with the equipment [1, 5].
These contradictions can be resolved only on the basis of clarifying the physiological mechanisms of athletes' movement control, in particular mechanisms of maintenance of balance in the final phase of the punch.
The purpose of the study was to examine physiological mechanisms of enhancement of motor actions in the final phase of the blow in senior boxers.
Materials and methods. Two groups were formed: experimental group and control group (CG) made of 11 persons (4 - candidates for master of sports, 7 - 1st sports grade) each. 17-23-year old athletes comprised the age group. Boxers of both of the groups performed the single effective direct right hand punch in the head on a punch bag during a round (3 min). Boxing mitts (10 oz) in the experimental group and bag gloves - in the control group were used to prevent injuries.
The study was carried out on the stabilographic analyzer "Stabilan - 01-2" [3], the following parameters were recorded: displacement in frontal plane, displacement in sagittal plane, ellipse area, quality of balance function. The body and arm muscle bioelectrical activity was registered using the neuromioanalyzer NMA-4-01 "Neuromian" when performing an effective direct punch [4].
The results obtained were processed by the methods of variation statistics, reliability was assessed using the nonparametric Mann-Whitney test.
Results and discussion. In the studies of athletes' foot positions the indicator "displacement in frontal plane" is assumed to give the most objective assessment of the transfer of body weight from the right foot to the left, showing the rotation axis extending in the final phase of the punch. The optimum result in this index in the experimental group was shown by boxers - candidates for master of sports, whose technical skills are better than of rated athletes, meaning, that it can serve as a model for them in this study. It should be emphasized that we do take for the standard the technique of athletes - candidates for master of sports, and believe it is more perfect only in the present experiment.
The motion axis in athletes of the control group of the 1st sports grade (Tab. 1) was (with the clear violation of the impact action technique) over the right shoulder and right leg. This position of the axis does not provide development of maximum power of the impact action. This result of athletes in the index "displacement in frontal plane" was less than the optimal data by 142,7 %. The index of the boxers of the experimental group was less than the alleged result by 94,6 %.
Table 1. Stabilographic indices when making effective right hand punches in senior boxers, X±m
Groups Stabilographic indices Boxers of the 1st sports grade Boxers - candidates for master of sports
Experimental Displacement in frontal plane MO(x), mm -37,41±4,67*# -19,22±2,09*
Displacement in sagittal plane MO(y), mm 49,35±3,78*# 60,86±4,11*
Ellipse area, sq.m. 30467,19±3742,68*# 21862,38±1421,59*
Quality of balance function, % 14,08±1,58* 16,16±1,73*
Control Displacement in frontal plane MO(x), mm 8,21±4,61# -0,14±0,07
Displacement in sagittal plane MO(y), mm 35,95±3,91 47,02±3,07
Ellipse area, sq.m. 13065,63±1272,78 14818,12±965,14
Quality of balance function, % 7,52±0,78 7,64±0,93
* - reliability of differences between the experimental and the control groups (p<0,05);
# - reliability of differences between the groups of the 1st sports grade and candidates for master of sports (p<0,05).
Analyzing the index "displacement in the sagittal plane", we evaluated the parameters of athletes' body weight transfer in the direction of the punch. The index "displacement in the sagittal plane" of athletes of the 1st sports grade of the experimental group exceeded the control values by 37,3 %.
In terms of the "ellipse area" we estimated the width of placing feet in a fighting stance in an impact of hand with a target. This indicator is very important because it has a significant influence on the stiffness of the kinematic chain and makes it easier to take the starting position
after the impact, which significantly improves the efficiency of athlete's actions. The index "ellipse area" in boxers of the 1st sports grade of the experimental group was higher than the control values by 133,2 %.
We assume that the index "quality of balance function" most objectively estimates boxer's stability in the contact of fist with an apparatus in the final phase of the punch. Boxers of the 1st sports grade of the experimental group had the value of this index exceed the control level by 87,2 %.
In boxers - candidates for master of sports of the control group (Tab. 1) the rotation axis in the final phase of the punch passed through the middle of CCM (common center of mass), which prevented a proper use of the inertia of the body, distorting the biomechanical data of the punch. In athletes of the control group the index "displacement in the frontal plane" was lower than the optimal results by 99,3 %.
The index "displacement in the sagittal plane" of boxers - candidates for master of sports of the experimental group exceeded the control level by 29,4 %. The index of the result of "ellipse area" in boxers - candidates for master of sports of the experimental group exceeded the control data by 47,5 %. The index "quality of balance function" of boxers - candidates for master of sports of the experimental group exceeded the data of the control group by 111,5 %.
In the second part of the work electrical activity of athletes' muscle groups was studied when performing a direct effective punch.
In amateur boxers of the experimental group the average amplitude of electrical activity of the biceps muscle of arm was 47.7 % lower (Tab. 1.) than in the control group, and oscillation frequency was lower than the control values by 40, 6%. This indicates that the athletes of the experimental group when striking a punch have only those arm muscles work which play a direct role in the impact action. At the same time, the athletes of the control group have an increased activity of muscle groups not directly participating in the impact action, which significantly reduces the speed indices of the punch.
The range of activity of the triceps muscle of arm of beginner boxers of the experimental group exceeded the control values by 25,5%, and the oscillation frequency exceeded the control values by 175.8 % , testifying to the correct biomechanical base of impact action and higher motor coordinating mechanisms of direct punch.
The electrical activity of intercostal muscles of beginning boxers of the experimental group exceeded the control values in the average amplitude by 49,2%, and oscillation frequency was higher than the control value by 66%. This is due to the fact that qualified athletes more clearly emphasis the exhalation in the moment of impact action, which gives more stiffness to the whole kinematic when performing an impact action.
The range of bioelectrical activity of the abdominal external oblique muscle of beginning boxers of the experimental group exceeded the control value by 53%, and oscillation frequency was higher than the control value by 155%. This indicates the more intensive involvement in the work of body muscles, which significantly improve speed and strength characteristics of an impact action.
In athletes of the 1st sports grade the range of activity of the biceps muscle of arm in the experimental group was 48.8% lower (Tab. 2) than in the control group, and the oscillation frequency was lower than the data of the control group by b41.5%. The average amplitude of bioelectrical activity of the triceps muscle of arm in athletes of the experimental and control groups did not statistically differ, while the oscillation frequency in the experimental group exceeded the control data by 144.2%. The range of oscillations of intercostal muscles and the oscillation frequency of athletes of the experimental group exceeded the control values by 41,1% and 50,8% respectively. The average amplitude of activity of the abdominal external oblique muscle and the oscillation frequency of athletes of the experimental group was statistically higher than the control values by 35,2% and 187% respectively.
Table 2. Indices of electrical activity of muscles involved in effective right hand punches, X±m
Groups Grounds of muscles Boxers of the 1st sports grade Boxers - candidates for master of sports
Medium frequency, Hz Average amplitude, mkV Medium frequency, Hz Average amplitude, mkV
Experi mental biceps muscle of arm 6,70±1,21* 522,79±54,70* 6,12±0,31* 419,52±27,80*
triceps muscle of 19,17±2,37* 1161,31±17,03* # 22,41±1,49* 1383,81±15,54 *
arm
intercostal muscles 24,13±1,72* 1095,06±24,03* # 27,85±1,67* 1224,37±26,21 *
abdominal external oblique muscle 14,12±3,11*# 1190,71±42,21* # 25,33±2,75* 1285,50±11,22 *
Control biceps muscle of arm 11,46±1,19 1021,98±27,36 10,96±1,94 985,15±48,64
triceps muscle of 7,85±1,11 1034,60±17,44 13,25±1,65 1052,58±13,27
arm
intercostal muscles 16,00±1,47# 776,12±32,15# 20,16±0,71 943,60±21,09
abdominal external 4,92±0,59# 880,58±39,36# 12,53±1,18 1036,43±20,14
oblique
__muscle ____
* - reliability of differences of the experimental and control groups (p<0,05);
# - reliability of differences between the groups of the 1st sports grade and candidates for master of sports (p<0,05).
The average amplitude of the biceps muscle of arm of boxers - candidates for master of sports of the experimental group was statistically lower than the control value by 57.4%, and the oscillation frequency was inferior to the index of the control group by 44.2%. The value of the average amplitude triceps muscle of arm exceeded the control values by 31,5%. The oscillation frequency of the athletes of the experimental group exceeded the control value by 69,1%. In the experimental group the values of average amplitude and oscillation frequency of intercostal muscles exceeded the control values by 29,8% and 38,1% respectively. The average amplitude of activity of the abdominal external oblique muscle in athletes of the experimental group exceeded the control values by 24% and oscillation frequency - by 102,2%.
Table 3. Indices of electrical activity of boxers' hand muscles (dorsal interosseus) when performing effective direct right hand punches, X±m__
Classification of athletes Medium frequency, Hz Average amplitude, mkV
Boxers of the 1st sports grade Experimental 198,00±17,98# 381,25±14,76#
Control 217,00±35,74# 388,50±21,27#
Boxers -candidates for master of sports Experimental 375,50±45,28 858,00±67,37
Control 392,50±27,09 892,00±77,17
# - reliability of differences between the groups of the 1st sports grade and candidates for master of sports (p<0,05).
The characteristics of electrical activity of hand muscles (dorsal interosseus) of athletes of different qualifications of the experimental and the control groups did not significantly differ (Tab. 3). Meanwhile, regarding athletes of the 1st sports grade both the amplitude and the oscillation frequency were significantly lower than in the group of candidates for master of sports. Obviously, the factor of hand fixation also significantly contributes to ensuring the efficiency of the final phase of direct effective punch.
Conclusion. Thus, efficiency of boxers' motor actions in the final phase of the punch is provided by two groups of factors. The first one is associated with ensuring stiffness of the kinematic chain via coordination of motions with single body parts and formation of an axis of motion through a support foot, common center of gravity and right hand used to perform a punch. Moreover, athlete's stability improves in the final phase of the punch via increasing the ellipse area the trajectory of the common center of gravity is projected to.
Another factor of punch efficiency is optimal coordination of muscle activity, shown in the enhanced bioelectrical activity of muscles directly involved in an impact action and inhibition of antagonists. The punch strength is also enhanced by body muscles involved in the action, including expiratory muscles - exhale stress in the final phase of a punch.
The use of hand protectors - boxing mitts - enhances stiffness of the kinematic chain and consequently intensifies the impact force in the very final phase.
References
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