Dr.Med., Professor L.V. Kapilevich^{1, 2}
Postgraduate A.V. Razuvanova²
Postgraduate E.V. Medvedeva²
PhD E.V. Koshel'skaya^2
1National Research Tomsk State University, Tomsk
²National Research Tomsk Polytechnic University, Tomsk

Keywords: biomechanical data analysis, Motion Tracking method, standing long jump, aerial position.

Background. Modern information technologies are being increasingly applied in the national sports including the refereeing service that is now supported by due technical equipment and software and better protected from human errors as even a slightest technical blander may be easily identified and analyzed in the process [1, 5]. These modern developments offer new opportunities for the athletic training process being improved based on the applicable high technologies [7]. The present study was designed to apply a modern technology based on the base motor skill biomechanics analysis to explore the skill formation mechanisms in elite athletes and thereby find new ways to improve the education/ training process efficiency [2, 4]. For doing that, the relevant modern digital technologies will be applied to find out the contributions of natural individual physiological characteristics to athletic motor skills; and to explore the motor activity control system adjustment mechanisms responsible for the motor skill performance process [3, 6].

Objective of the study was to bring to the forefront the motor skill biomechanics analyzing method to support the motor skills mastering process.

Methods and structure of the study. Subject to the study was a standing long jump as the case motor action. A result of a long jump may be assumed as technically dependent on the efficiency of the push-up action phase, and it is this jump phase that we selected for a special analysis under the study to attain the above stated objective.

Subject to the study were 30 male athletes aged 17 to 24. The athletes were split up into two skill-specific groups based on their standing long jump performance skills. Study Group was composed of the highly-skilled athletes (n=16) specializing in speed-strength-intensive track and field sports and having formal four-years-plus track records. Reference Group (n=14) was composed of the Sport Department students going in for other sport disciplines and having no formal qualifications in the track and field sport.

A Motion Tracking method based on the digital frame-by-frame video capture technology and analyses was used in the study, with the video captures of 100 frames per second obtained by Vision Research Phantom Mire X2 video-camera. StarTraceTracker 1.1 VideoMotion® software toolkit was used for the data analyses and graphical processing.

Study results and discussion. In the push-up phase of the jumping sequence, the jumper’s feet seem to be in a static position at the first sight, with the main role being played by the arms performing the swing-up action with the torso acting as a lever for the swinging sequence. This seems to be the case at least for the Reference Group athletes who were tested to perform the push-up action with the feet and pelvis being kept in a static position. That means that they first make a sub-squatting movement bending their knee ankles and swinging up their arms when pushing the torso forward.

“Sample performance technique” of highly-skilled athletes

Highly skilled athletes are known to give a top priority to the push-up phase since every action in the push-up sequence is critical for success of the jump. Our data analyses showed that the push-up sequence in the Study Group may be described as a much more complex coordinated motor process that that in the Reference Group.

It is in a vertical position (with the torso angle of 180^◦) that the motor sequence is started up by the straight arms moving up. In the top point of the arms movement, the elbow joint angle is ≥150^◦. With the arms moving up, the torso bends forward at around ≈ 200°. That means that the jumper pushes the bending torso forward with the straight arms being swung up; and this element of the movement sequence is never found in the Reference Group actions. Then the arms are sharply pushed down, the torso bends further forward in a sub-squatting action performed mostly by the knee and ankle joints. With the feet actively contributing to the action, the body mass is shifted to the tips with the heal taking off the ground. It should be noted that the sub-squatting action is never deep with the knee joint angle being kept at around ≈90°. It is in the moment of the vertical body position being transformed to the sub-squatting position that the athlete will swing the straight arms down and behind the back. The torso angle in the top point of the swing action is around ≈70°, and this angle was found to be much higher than that in the Reference Group. Going next is the take-off action as a climax point in the motor sequence. Both groups were found largely different in the knee joint straightening element of the take-off moment. The Study Group athletes were found to fully extend the knee joint in the take-off point with the knee angle coming to ≈180°and the torso being stretched diagonally upward to the jump line.

Motor skill performance technique at the skill mastering stage

It is from the vertical body position (with the torso angle of 180^◦) that the bent arms will move up to the head. In the top point of the arm swinging-up movement, the elbow joint angle is ≥70^◦, with the torso kept in a static position. Then the bent arms are sharply pushed down with the torso bent and pushed forward to a sub-squatting position mostly by the knee-bending action. In this moment of the vertical position being transferred to the sub-squat, the jumper will swing the arms down smoothly straightening the arms up to 170◦ when they come behind the back. The torso bending angle in the top point of the arms swinging action is ≥100^◦. Going next is the take-off action as a climax point in the motor sequence. It is only by this point that the Reference Group athletes would activate the feet and take off the heels with the body weight shifted forward to the toes. The take-off action, as demonstrated by the study data and analyses, is a fairly standard action performed largely in the same way in both of the groups: the arms are swung up forward and straightened diagonally upward along the jump line till the feet take off to the aerial position. Both groups were found largely different in the knee joint straightening in the take-off moment. The Reference Group athletes were found to leave the knee joints slightly bent at the angles of around ≈150°.

Discussion. The motor sequence performance by the unskilled Reference Group (compared to the skilled Study Group) was found largely simplified and rather mimicking the right jump performance technique. The difference in the group performance techniques is naturally and obviously demonstrated by the distances achieved by both group athletes, albeit it is only a face value. The Motion Tracking method gives the means to link the jump distance to the Body Mass Centre (BMC) horizontal velocity rate at the take-off moment, since this rate is critical for the jump performance skills on the whole. The inter-group difference of the BMC horizontal velocity rates was estimated at ≈1000 mm/s, with the Study Group rates averaging at ≈ 2200 mm/s versus the Reference Group rates of ≈ 1200 mm/s. If we now examine the x-axis-wise movement components of both group curves showing the take-off phase duration, we will find that the Reference Group athletes are four times faster in the take-off movement sequence, albeit their BMC velocity rate is nearly two times lower. 

Conclusion. The study data and analyses showed the standing long jump movement sequence of the beginner athletes being qualitatively and largely different from that of the highly-skilled athletes. The beginner athletes’ jumping motor sequence may be described as a mix of loosely coordinated actions like arm swings, sub-squat and take-off. In contrast to them, the Study Group athletes were found to perform the standing long jump movement as a harmonized single motor action with each of its elements being strictly coordinated with the others in a perfect smooth process. The perfect motor skills manifest themselves in the high BMC velocity rate of the jump and high distance achieved.

The beginner athletes are likely to perform the standing long jump movement sequence as a mix of elementary motor stereotypes loosely coordinated with one another. A good training process will help harmonize these elements to combine the virtually independent motor elements into a smooth stereotype of the subject motor skill, with every element being harmonically activated in the jump process. The training systems designed to help master this motor stereotype will secure an optimal jumping sequence performance technique to attain the best possible result.

To summarize the above study data and analyses, we would state that an optimal motor skill mastering system will be based on the jumping sequence being shaped up on the whole rather than its every element being learned separately from the others. The best and most grounded approach, in our view, is to design the optimal jump performance model based on the biomechanical data analyses and shape up the target skills in the athletes with the relevant information technologies and real-time data processing concepts being efficiently applied.

The study was performed with financial support from the Russian Research Foundation Project #16-18-00016

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Corresponding author: kapil@yandex.ru

Abstract
The article considers practical experience of biomechanical data analysis being applied for the instant performance rating purposes in the motor skills mastering and sample technique formation process. A Motion Tracking method based on the digital frame-by-frame video capture analysis was used in the study. The study gave the grounds to conclude that the optimal long jumping technique modelling process based on the biomechanical data analysis and motor skill formation with support of real-time process data processing technology is efficient and beneficial.