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KinectX (KX) and KinectX Pro (KXP) are two specific applications for the training and evaluation of precision in body motion coordination. KinectX Pro was designed to provide an evaluation of efficiency of Ultra Slow Motion Intelligent Training (USMIT) for precision in motor coordination. KinectX was designed to provide direct feedback during the USMIT training in order to know the proper constant speed in ultra slow motions (10 mm/s). 142 voluntary subjects participated in four sets of trials (a total of657 tests): (1) preliminary tests (N=8); (2) motor coordination and psychological trait correlation tests (N=100); (3) precision progress in motor coordination tests (N=8); (4) motor coordination tests (N=27). Five advantages of KX and KXP were identified: (1) "no strings" movement; (2) "live" speed feedback; (3) trajectory feedback; (4) good sensor sensitivity (up to 30 evaluations per second); (5) easy relocation of KX and KXP systems. Two major disadvantages were identified and corrected during testing: (1) high sensitivityto light intensity variations; (2) high sensitivityto infrared radiations. One minor disadvantage: (1) variations inthe test results with variations in the subject's position vs. sensor. A guide for the optimal use of both applications was completed, tested and used in the trials. A beta version was completed for both KX and KXP and successfully used in the trials andthe training of athletes, members of the Romanian Olympic Team 2018. KinectX and KinectX Pro are reliable instruments in the training and evaluation of precision in motor coordination, based on the USMIT program.
Abstract: KinectX (KX) and KinectX Pro (KXP) are two specific applications for the training and evaluation of precision in body motion coordination. KinectX Pro was designed to provide an evaluation of efficiency of Ultra Slow Motion Intelligent Training (USMIT) for precision in motor coordination. KinectX was designed to provide direct feedback during the USMIT training in order to know the proper constant speed in ultra slow motions (10 mm/s).
Material and method. 142 voluntary subjects participated in four sets of trials (a total of657 tests): (1) preliminary tests (N=8); (2) motor coordination and psychological trait correlation tests (N=100); (3) precision progress in motor coordination tests (N=8); (4) motor coordination tests (N=27). Five advantages of KX and KXP were identified: (1) "no strings" movement; (2) "live" speed feedback; (3) trajectory feedback; (4) good sensor sensitivity (up to 30 evaluations per second); (5) easy relocation of KX and KXP systems. Two major disadvantages were identified and corrected during testing: (1) high sensitivityto light intensity variations; (2) high sensitivityto infrared radiations. One minor disadvantage: (1) variations inthe test results with variations in the subject's position vs. sensor.
Results. A guide for the optimal use of both applications was completed, tested and used in the trials. A beta version was completed for both KX and KXP and successfully used in the trials andthe training of athletes, members of the Romanian Olympic Team 2018.
Conclusion. KinectX and KinectX Pro are reliable instruments in the training and evaluation of precision in motor coordination, based on the USMIT program.
Keywords: precision in motor coordination; USMIT.
I. INTRODUCTION
The development of the training program based on ultra slow motions, USMIT (Ultra Slow Motion Intelligent Training) as a prophylaxis[1] for motor cortex fatigue syndrome[2], either in the acute form (through the motor impact component) or in the chronic form (through the mental impact component), involved designing a feedback system for the adjustment of execution speed in trainingspecific movements. The USMIT value is the effect of increasing the degree of resistance in highprecision motor coordination [1].
Performing ultra slow motions (USM - motions at a constant speed of 10-25mm/s) [3] is rather a desideratum than a possibility, being most likely a limit of the human neuromotor ability to adjust agonist and antagonist muscle contractions [3, 5]. To achieve the training and assess the evolution of the motor coordination ability, the rough speed approximation system, based on the approximation of limb trajectories, the height of the athlete (subject) and the movement execution time (an algorithm used for the Ultra Slow Motion Training application, version 2.0.28, for iOS), does not allow a satisfactory evaluation of the optimal working speed (at least in the absence of sustained USMIT training) and does not allow the evaluation of the training effectiveness.
In this regard, two Windows 10 applications using as an external resource a camera for the human body motion analysis, Kinect 2.0, have been developed, applications that track the position of the upper limbs during a standardized exercise, with feedback for the user (KinectX 1.0) and without feedback for the user, with an evaluation purpose (KinectX Pro) [3].
II.MATERIAL, METHOD ANDRESULTS
The validation of KinectX and KinectX Pro testing systems was divided into two stages:
a. Stage 1 (E1). Validating an initial system and establishing the statistical calculation formulas for the two applications.
b. Stage 2 (E2). Tracking the two main working hypotheses (#1. good ability for ultra slow motion coordination correlates with good dedication ability and low impulsiveness [4, 5] (E21); #2. the USMIT training produces a significant improvement inmotor coordination precision, in both the standardized KinectX Pro testing and the specific tests for different sports branches [1] (E22))
2.1 Material and method
A. Subjects
a. Stage 1 (E1). A number of 8 male volunteers aged between 16 and 47 years (31.8±9.7), with various motor (sports) abilities (a performance athlete, three sedentary subjects and four subjects with good motor abilities and rich personal experiences in leisure sports) participated in 160 preliminary tests aimed to establish the statistical calculation formula for the parameters of ultra slow motion assessment.
b. Stage 2 (E2). A number of 134 subjects participated in 8 testing programs (497 tests): 6 testing programs (N=126) for the correlation between precision in ultra slow motions and good dedication ability and low impulsiveness (evaluations based on the Existence Scale- ESK [6, 7] and the Perceived Wellness Scale- PWS [8]) - (E21); 2 testing programs (N=8) for the significant improvement in motor coordination precision through the USMIT program - (E22).
In terms of motor experience and psychological profile, the subjects participating in stage E21 were: medical students, master students in sports performance, performance athletes with national and international results [4, 5] (N=63), resident physicians and specialist psychiatrists (N=26), psychotherapists [5] (N=10), staff from the national emergency services (physicians, nurses, firemen, paramedics (N=27). The subjects participating in stage E22 were members of the national biathlon team (N=7) and a volunteer subject with high motor coordination abilities, but with no experience in performance sports [1].
B. Training. The subjects participating in stage E22 were the only ones who benefited from a specific personalized training program, a variation of USMIT.
C. Evaluations. Three evaluation programs specific to the two stages, E1 and E2, were planned and carried out.
C.1. For stage E1:
C.1.1. Self-evaluation of general health status: sleep cycles in the previous nights, resting heart rate, subjective evaluation of psychological and physical states on a scale from 0 to 5 (0 - relaxed or rested, 5 - tense or tired).
C.1.2. Testing precision in coordination with KinectX Pro. Four versions of the assessment system (PIKI v. 1.0-4.0) were tested.
C.1.3.Psychological evaluation: evaluation of perceived wellness, impulsiveness and dedication ability (PWS, ESK)
C.2. For stageE2:
C.2.1. Self-evaluation of general health status: sleep cycles in the previous nights, resting heart rate, subjective evaluationof psychological and physical states ona scale from 0 to 5 (0 - relaxed or rested, 5 - tense or tired)
C.2.2. Testing precision in coordination. Version 4 for the KinectX Pro system (PIKI 4.0) was used. The chosen testing algorithm aimed at the motion analysis for the intervals At1=0-15s, At2=2150s and At3=0-50s, and two intervals, At=0.11±2s and At=0.33±6s, were used to calculate the average speed (in the mode) [3]. An error correction was set by removing extreme values (10% of overall determinations per evaluation). In the absence of homogeneous results in the preliminary tests, as an indicator of precision in coordination, the median quartile for average speed values (in the mode) was established [3], as well as the standard deviation for average speed values (in the mode) where the results became homogeneous [3].
C.2.3.Psychological evaluation: evaluation of perceived wellness, impulsiveness and dedication ability (PWS, ESK).
C.2.4. Evaluation of the reaction speed (time).
C.2.5. Evaluation of motor coordination abilities (Sensory Organization Test, Neur°Com System 8.6.0).
C.2.6. Specific evaluations for sports fields (tennis, biathlon).
C.2.7. Other recorded parameters: diet, evolution of exercise parameters (for E22).
C.3. Evaluation of parameters for the verification and validation of KinectX and KinectX Pro systems. The tests were performed in parallel with the recording of the test-environment parameters (temperature, brightness, exposure to natural or artificial light), with variations in the technical parameters of the hardware system used in the tests, other variations in the testing system (test distance and angle, background color).
D. Results
D.1. Results for evaluations C.1. and C.2.
D.1.1. Evaluations showed repeated correlations between impulsiveness and the dedication ability, on the one hand, and the high-precision coordination ability in ultra slow motions [4, 5] assessed with the KinectX Pro system, on the other hand. The general background highlighted an unexplored remaining potential as regards the clear perception of reality and the dedication ability, with a satisfactory perception of the health status [4, 5]. An improvement in tennis-specific performance was confirmed following the exclusive USMIT training [1]. It was also found an increase in sports performance for biathlon, revealed by higher precision in the shooting component after the USMIT training, within the evaluation performed in the first part of the 2017-2018 season for one subject, a member of the national biathlon team (precision has increased to 93% [9]).
D.1.2. The distribution of average speed results for the tests in the absence of specific USMIT training showed a non-homogeneous distribution for the three evaluated intervals: At1=0-15s, At2=2150s and At3=0-50s (Table 1), confirming the preliminary research [3].
D.1.3. Testing precision in coordination. The evolution of the coefficient of variation during the tests showed a tendency towards non-homogeneous variations, similar for the left hand and the right hand, indicating thus a real human difficulty in performing this type of exercise [1].
D.2. Results for evaluations C.3.
In both testing stages, E1 and E2, the tracked parameters were those that had an impact on the test results and were considered not to be related to the performance of the tested subjects.
D.2.1. Stage E1. Operation of the hardware system. Two Windows 10 systemswere tested (#1 Intel® Core i5, 2,2Ghz, 8GB; #2 Intel® Core i7, 2,6Ghz, 8GB). The results were marked by significant errors (loss of control over the number of tests per second, a decrease from 10 tests/s to 4±3 tests/s) by the simple variation in using the hardware system with or without an alternating current connection. Also, when operating with batteries (Asus, GL552J, Li-ion, A41N1424), the number of tests was influenced by the simultaneous running of other applications, paradoxically, increasing the number of tests per second, but without improving the test accuracy (6±4 tests/s). The source of these variations is most likely a limitation in the processor operation due to the BIOS setting.
D.2.2. Two types of testing were performed: with a number of 3 tests/s and 10 tests/s, respectively. Following stage E1, it was established that the baseline testing consisted of the 10 tests/s, due to the need to eliminate a significant number of calculation errors for the average speed, with erroneous values of 142±64.38 for a target test speed of 10 mm/s andmean values of 12.91±6.50 in the absence of errors (N=120). The number of test errors was 2.86±0.98 on average. A number of 40 additional tests were performed with a target test speed of 0 mm/s and mean values of 6.76±4.98 for checking the error-elimination formula, giving up 10% of the total test results, 5% for maximum results and 5% for minimum results.
D.2.3. The distance from the Kinect 2.0 camera wasset at 130±10 cm, for optimal testing. The tests followed a variation in distance, from 100±10 cm to 150±10 cm. The test angle was set at - 15°±5°.
D.2.4. Stage E2. Of the total of 497 tests, 1.8% showed calculation errors for the average speed, which could be corrected by adjusting the brightness of the test-environment parameters (the recommended value, based on determinations, is 2000±100 lux, the equivalent of an illumination generated by at least 800W, preferably 1000W), or by removing the infrared radiation source (by completely eliminating the natural light source).
E. Observations and comments
E.1. Advantages of KinectX and KinectX Pro evaluation and training systems:
a. Free-motion performance, with the possibility to establish exercises varying in the trajectory and the symmetric or asymmetric coordination of the upper limbs (KinectX).
b. Real-time motion guidance, depending on the trajectory.
c. Feedback for the speed with which exercises are performed.
d. Maximum fineness of the tests for At=0.033s intervals and the possibility to use the tests for At=0.1s intervals, and reducing the necessary resources for data processing.
e. Convenience in relocating the test system.
f. These are the only systems specifically designed for the USMIT training.
E.2. Disadvantages of KinectX and KinectX Pro evaluation and training systems:
a. Sensor sensitivity to brightness variation.
b. Sensor sensitivity to infrared radiation sources.
c. Closing of theMicrosoft development line for the Kinect 2.0. device. [10]
III.CONCLUSIONS
Specific testing for precision in motor coordination has been confirmed to be correlated with psychological aspects associated with the control of impulsiveness and dedication ability [4, 5]. KinectX Pro tests provide the opportunity of opening a further research direction to establish easily quantifiable indicators for these psychological parameters. The testing system has proven to be a practical and accessible method for the training and evaluation of coordination precision [3].
The obtained results support the validation of KinectX and KinectX Pro as systems for the specific evaluation and training through ultra slow motions (USM).
To increase the accuracy of the results when using the KinectX and KinectX Pro evaluation systems, one should take into account the test distance and angle, the light intensity and the elimination of infrared radiations from the test environment. As new generations of sensors develop [11], a better and easier quantification of training through ultra slow motions will be achieved.
Acknowledgements
UNEFS Bucharest, Doctoral School
Brains Software
R. Barn Foundation for Medicine and Health
Search and Rescue Team in Special Situations
Mental Health Association of South-Eastern Europe
Reference Text and Citations
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[11] https://software.intel.com/en-us/realsense/d400
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