Joint Under and Over Water Calibration of a Swimmer Tracking System

Haner, Sebastian; Svärm, Linus; Ask, Erik; Heyden, Anders

doi:10.5220/0005183701420149

Cited by 11 publications

(12 citation statements)

References 13 publications

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“…On race completion, the automatic postprocessing produced a panning video file (MPEG-4 Part 14) and a synchronized Excel sheet containing the center of the head displacement data relative to the global coordinate system, which were used for further analysis. For more details regarding the set-up, calibration and post-processing, see Olstad et al 2 and Haner et al 14 Key points of the underwater start sequence (from when the hands enter the water until the head regains the water surface) were qualitatively analyzed by five experts (more than 30 hours of experience) 15 randomly paired using a blinded technique based on underwater side and aerial views, previously used in breaststroke, 16,17 and validated for front crawl. 15 If the difference between the two experts did not exceed 0.04 s, the mean was accepted to validate the key point.…”

Section: Methodsmentioning

confidence: 99%

Arm–leg coordination during the underwater pull-out sequence in the 50, 100 and 200 m breaststroke start

Olstad

Gonjo

Conceição³

et al. 2022

Journal of Science and Medicine in Sport

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This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

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Section: Methodsmentioning

confidence: 99%

Arm–leg coordination during the underwater pull-out sequence in the 50, 100 and 200 m breaststroke start

Olstad

Gonjo

Conceição³

et al. 2022

Journal of Science and Medicine in Sport

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“…The object was pulled in a zigzag pattern starting at the wall in the middle of the racing lane and thereafter with an approximate 1–2 m of horizontal displacement from left to right covering the 25 m pool length. The calibration process consisted of the following five steps and was performed by the manufacturer: (1) intrinsic in-air calibration of all cameras, (2) capture calibration object, (3) detect calibration markers, (4) initialize calibration object pose and camera extrinsic parameters, and (5) refine parameters using bundle adjustment (described in detail by a previous study [ 24 ]). The mean reprojection error for the calibration object was 2.0 pixels, corresponding to a 0.025° angular error and 0.006 m linear error.…”

Section: Methodsmentioning

confidence: 99%

Key Factors Related to Short Course 100 m Breaststroke Performance

Olstad

Wathne

Gonjo

2020

IJERPH

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Background and aim: To identify kinematic variables related to short course 100 m breaststroke performance. Methods: An automatic race analysis system was utilized to obtain start (0–15 m), turn (5 m before the wall until 10 m out), finish (95–100 m), and clean swimming (the rest of the race) segment times as well as cycle rate and cycle length during each swimming cycle from 15 male swimmers during a 100 m breaststroke race. A bivariate correlation and a partial correlation were employed to assess the relationship between each variable and swimming time. Results: Turns were the largest time contributor to the finishing time (44.30 ± 0.58%), followed by clean swimming (38.93 ± 0.50%), start (11.39 ± 0.22%), and finish (5.36 ± 0.18%). The finishing time was correlated (p < 0.001) with start segment time (r = 0.979), clean swimming time (r = 0.940), and 10 m turn-out time (r = 0.829). The clean swimming time was associated with the finishing time, but cycle rate and cycle length were not. In both start and turns, the peak velocity (i.e., take-off and push-off velocity) and the transition velocity were related to the segment time (r ≤ −0.673, p ≤ 0.006). Conclusions: Breaststroke training should focus on: (I) 15 m start with generating high take-off velocity, (II) improving clean swimming velocity by finding an optimal balance between cycle length and rate, (III) 10 m turn-out with maintaining a strong wall push-off, and (IV) establishing a high transition velocity from underwater to surface swimming.

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“…This system allows for automatic detection of two-dimensional head displacement and the timing of the beginning of each arm pull motion, based on an image processing technique and the side camera views obtained from the ten cameras, with a sampling frequency of 50 Hz. Detailed calibration algorithm for the system has been described in Haner et al (2015). The mean velocity (V 50m ), stroke length (SL), and stroke frequency (SF) of each swimmer were calculated for all stroke cycles using the head displacement and stroke timing data obtained by the AIM system.…”

Section: Front Crawl Performancementioning

confidence: 99%

The Relationship Between Selected Load-Velocity Profile Parameters and 50 m Front Crawl Swimming Performance

et al. 2021

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The purpose of the present study was to establish relationships between sprint front crawl performance and a swimming load-velocity profile. Fourteen male national-level swimmers performed 50 m front crawl and semi-tethered swimming with three progressive loads. The 50 m performance was recorded with a multi-camera system, with which two-dimensional head displacement and the beginning of each arm-stroke motion were quantified. Forward velocity (V50m), stroke length (SL) and frequency (SF) were quantified for each cycle, and the mean value of all cycles, excluding the first and last cycles, was used for the analysis. From the semi-tethered swimming test, the mean velocity during three stroke cycles in mid-pool was calculated and plotted as a function of the external load, and a linear regression line expressing the relationship between the load and velocity was established for each swimmer. The intercepts between the established line and the axes of the plot were defined as theoretical maximum velocity (V0) and load (L0). Large to very large correlations were observed between V50m and all variables derived from the load-velocity profiling; L0 (R = 0.632, p = 0.015), L0 normalized by body mass (R = 0.743, p = 0.002), V0 (R = 0.698, p = 0.006), and the slope (R = 0.541, p < 0.046). No significant relationships of SL and SL with V50m and the load-velocity variables were observed, suggesting that each swimmer has his own strategy to achieve the highest swimming velocity. The findings suggest that load-velocity profiling can be used to assess swimming-specific strength and velocity capabilities related to sprint front crawl performance.

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Joint Under and Over Water Calibration of a Swimmer Tracking System

Cited by 11 publications

References 13 publications

Arm–leg coordination during the underwater pull-out sequence in the 50, 100 and 200 m breaststroke start

Arm–leg coordination during the underwater pull-out sequence in the 50, 100 and 200 m breaststroke start

Key Factors Related to Short Course 100 m Breaststroke Performance

The Relationship Between Selected Load-Velocity Profile Parameters and 50 m Front Crawl Swimming Performance

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Joint Under and Over Water Calibration of a Swimmer Tracking System

Cited by 11 publications

References 13 publications

Arm–leg coordination during the underwater pull-out sequence in the 50, 100 and 200 m breaststroke start

Arm–leg coordination during the underwater pull-out sequence in the 50, 100 and 200 m breaststroke start

Key Factors Related to Short Course 100 m Breaststroke Performance

The Relationship Between Selected Load-Velocity Profile Parameters and 50 m Front Crawl Swimming Performance

Contact Info

Product

Resources

About

Arm–leg coordination during the underwater pull-out sequence in the 50, 100 and 200 m breaststroke start

Arm–leg coordination during the underwater pull-out sequence in the 50, 100 and 200 m breaststroke start