El uso de la tecnología de captura de movimiento para el análisis del rendimiento deportivo

In sport performance, motion capture aims at tracking and recording athletes’ human motion in real time to analyze physical condition, athletic performance, technical expertise and injury mechanism, prevention and rehabilitation. The aim of this paper is to systematically review the latest developments of motion capture systems for the analysis of sport performance. To that end, selected keywords were searched on studies published in the last four years in the electronic databases ISI Web of Knowledge, Scopus, PubMed and SPORTDiscus, which resulted in 892 potential records. After duplicate removal and screening of the remaining records, 81 journal papers were retained for inclusion in this review, distributed as 53 records for optical systems, 15 records for non-optical systems and 13 records for markerless systems. Resultant records were screened to distribute them according to the following analysis categories: biomechanical motion analysis, validation of new systems and performance enhancement. Although optical systems are regarded as golden standard with accurate results, the cost of equipment and time needed to capture and postprocess data have led researchers to test other technologies. First, non-optical systems rely on attaching sensors to body parts to send their spatial information to computer wirelessly by means of different technologies, such as electromagnetic and inertial (accelerometry). Finally, markerless systems are adequate for free, unobstructive motion analysis since no attachment is carried by athletes. However, more sensors and sophisticated signal processing must be used to increase the expected level of accuracy.En el ámbito del rendimiento deportivo, el objetivo de la captura de movimiento es seguir y registrar el movimiento humano de deportistas para analizar su condición física, rendimiento, técnica y el origen, prevención y rehabilitación de lesiones. En este artículo, se realiza una revisión sistemática de los últimos avances en sistemas de captura de movimiento para el análisis del rendimiento deportivo. Para ello, se buscaron palabras clave en estudios publicados en los últimos cuatro años en las bases de datos electrónicas ISI Web of Knowledge, Scopus, PubMed y SPORTDiscus, dando lugar a 892 registros. Tras borrar duplicados y análisis del resto, se seleccionaron 81 artículos de revista, distribuidos en 53 registros para sistemas ópticos, 15 para sistemas no ópticos y 13 para sistemas sin marcadores. Los registros se clasificaron según las categorías: análisis biomecánico, validación de nuevos sistemas y mejora del rendimiento. Aunque los sistemas ópticos son los sistemas de referencia por su precisión, el coste del equipamiento y el tiempo invertido en la captura y postprocesado ha llevado a los investigadores a probar otras tecnologías. En primer lugar, los sistemas no ópticos se basan en adherir sensores a zonas corporales para mandar su información espacial a un ordenador mediante distintas tecnologías, tales como electromagnética y inercial (acelerometría). Finalmente, los sistemas sin marcadores permiten un análisis del movimiento sin restricciones ya que los deportistas no llevan adherido ningún elemento. Sin embargo, se necesitan más sensores y un procesado de señal avanzado para aumentar el nivel de precisión necesario

Injuries and pathologies in beach volleyball players: A systematic review

The aim of this paper is to review the available literature published on injuries and pathology in beach volleyball. The databases consulted were the Web of Sciende and Pubmed. After establishing the criteria for selection and filtering, a total of 32 articles were selected. All items found can be classified into four research lines. First are the studies focused on specific injuries such as shoulder, shoveling, knee and foot. The second line of research focuses on the study of the incidence, prevalence and frequency of injuries of beach volleyball players, whereas the third line deals on infections reported in the literature produced by nematodes or fungi. Finally, the last line of research includes articles addressing different objectives related to health such as the effects of training programs related to injuries, influence of weather conditions on the players, as well as publications for validation of assessment instruments or develop of guidelines and protocols for the evaluation and diagnosis of injuries

Actividad de los bloqueadores durante el Campeonato de Europa Universitario de vóley playa

In this paper, we present a study of blocker’s activity in university beach volleyball players. A total of n=1166 blocking actions were analyzed from 24 European men's teams at the Ninth European Beach Volleyball Championship EUSA GAMES. The analysis of the videos was carried out using the free software program LongoMatch v.0.27. Statistical significance of the comparison of systems was calculated using the Z test to compare proportions. Results showed that blockaders do not have a leading role in the Direct Intervention (DI) of the ball (37%, p<0.001). The most blocking actions were Line Blocking (LB) (46.9%), Net Exits (NE) (21.1%) and Diagonal Blocking (DB) (18.1%). When comparing periods of points (F1: 1 to 7, F2: 8 to 14, F3: 15 to 21), statistical differences (p<0.001) where observed between periods F1 and F3 for the most used blocking actions: LB, NE and DB. Finally, similar efficiency values were observed for the most common blocking actions (29.3% for LB and 23.2% for DB). Higher efficiencies can be found in less common defensive actions, such as V Blocking (VB) (31.4%) and Fighting (F) (34.6%).En este artículo se presenta un estudio de la actividad del bloqueador en jugadores universitarios de voley playa. Fueron analizados un total de 1166 acciones de bloqueo de 24 equipos europeos masculinos durante el Noveno Campeonato Europeo de Voleibol de Playa EUSA GAMES. El análisis de los videos se llevó a cabo utilizando el programa de software libre LongoMatch v.0.27. La prueba estadística aplicada para la comparación de las proporciones fue la prueba Z. Los resultados mostraron que los bloqueadores no realizan una intervención directa (DI) de la pelota (37%, p <0,001) como acción principal defensiva. Las acciones de bloqueo más utilizadas fueron Bloqueo en Línea (LB) (46,9%), Salidas de Red (NE) (21,1%) y Bloqueo Diagonal (DB) (18,1%). Cuando se comparan periodos de puntos (F1: 1 a 7, F2: 8 a 14, F3: 15 a 21), se observan diferencias estadísticas (p <0,001) entre los períodos F1 y F3 para las acciones de bloqueo más utilizadas: LB, NE y DB. Finalmente, se observaron valores de eficiencia similares para las acciones de bloqueo más comunes (29,3% para LB y 23,2% para DB). Se pueden encontrar mayores eficacias en acciones defensivas menos comunes, como V Bloqueo (VB) (31,4%) y Lucha (F) (34,6%)

Time-motion analysis in professional championships of Valencian handball

Valencian handball is a sport with long tradition in the eastern coast of Spain. Among different variants of the game, this study has been focused in the professional version, also known as escala i corda. The aim was to determine the time distribution of periods of active play and rest time during matches. The variables studied were the total duration of the matches, games and game actions, differentiating real or active playing time from passive or rest time. We also quantified the number of games and the number of motor actions per match and per game in top professional competitions (Professional Escala i Corda Leagues and Cups, 2008-2011). Duration of an escala i corda match was between 57 min 43 s and 1 h 53 min 15 s, while the duration of active time was between 25 min 5 s and 50 min 46 s. The number of games per match varied between 11 and 17, and these had a mean duration of 4 min 35 s of active playing time. There are significant differences (p<0.05) in the duration of games, specifically between the three first periods (1-3, 4-6 and 7-9). Meanwhile, the mean time spent on the completion of each rally was 17.61 s ± 1.78 s. An improved understanding of players' absolute and actual game time can provide valuable information for planning specific escala i corda training exercises with respect to the duration and number of rallies

Defensive systems during the Men’s European University Beach Volleyball Championship

The analysis of performance in beach volleyball should consider the development of the set or game systems in connection with successful completion. In this paper, we present a study of defensive system in university beach volleyball players in order to determine the evolution throughout the set and effectiveness in relation to the performance factors of the game. A total of n=937 blocking actions were analyzed by means of video recordings from 24 European men's teams from 16 different nationalities at the Ninth European Beach Volleyball Championship EUSA GAMES. The analysis of the videos was carried out using the free software program LongoMatch v.0.27 by an experienced observer. Reliability performed on the intra-observer analysis showed a margin of error lower than 5%. Both effectiveness of the game systems and frequency of winning and not winning points were annotated for each period of points. Statistical significance of the comparison of systems was calculated using the Z test to compare proportions. Results showed that the most widely used game system was 2:1 with 67.2% (n=630) with statistically significance (p<0.001). Regarding effectiveness, system 2:1 presented an efficiency of success of 30.8% (n=194), whereas system 1:2 presented a moderately low value of 25.7% (n=79). When comparing periods of points (F1:1 to 7, F2: 8 to 14, F3: 15 to 21), system 2:1 showed higher effectiveness than 1:2 for the last two periods F2 and F3. Finally, a decrease in unscored point actions was observed in both systems between periods F1 to F3 (59.63% for 1:2 and 45.35% for 2:1)

Validity, reliability and usefulness of smartphone and kinovea motion analysis software for direct measurement of vertical jump height

Jumping is a simple exercise determined by several biomechanical and physiological factors. Measures of vertical jump height are common and easy to administer tests of lower limb muscle power that are carried out with several types of equipment. This study aimed to validate and address the usefulness of the combination of smartphone and computer-based applications (Smartphone-Kinovea) against a laboratory-based Motion Capture System. One hundred and twelve healthy adults performed three maximal-effort countermovement jumps each. Both instruments measured the heights of the 336 trials concurrently while tracking the excursion of the body center of gravity. The vertical velocity at take-off vto and the impulse J were computed with jump height h measures. Intraclass correlation coefficient (ICC) results indicated very high agreement for h and vto (0.985) and almost perfect agreement for J (0.997), and Cronbach's α=0.99. Low mean differences were observed between instruments for h: -0.22 ± 1.15 cm, vto: -0.01 ± 0.04 m/s, and J: -0.56 ± 2.92 Ns, all p1). Bland-Altman plots showed very low mean systematic bias ± random errors (-0.22 ± 2.25 cm; -0.01 ± 0.08 m/s; -0.56 ± 5.73 Ns), without association between their magnitudes (r2=0.005, r2=0.005, r2=0.001). Finally, very high to practically perfect correlation between isntruments were observed (r = 0.985; r = 0.986; r = 0.997). Our results suggest that the Smartphone-Kinovea method is a valid and reliable, low-cost instrument to monitor changes in jump performance in a healthy, active population diverse in gender and physical condition.This work was supported by the Vice-rectorate program of Research and Knowledge transfer for the Promotion of R&D at the University of Alicante (Ref. GRE18–19)

Reliability and validity of the Chronojump open-source jump mat system

Vertical jump performance is a commonly used test to measure lower-limb muscle power that is carried out with several types of equipment. The aim of this study was to validate an open-source jump mat (Chronojump Boscosystems) against a proprietary jump mat (Globus Ergo Tester). Sixty-three active sportsmen (age 23.3 ± 2.4 years) completed 8 maximal-effort countermovement jumps (CMJ). The heights of the 504 CMJ were measured from the two jump mats simultaneously. Reliability was examined with intra-class correlation coefficients (ICC), paired samples t-tests, coefficient of variation (CV) and Cronbach's ?. Bivariate Pearson's correlation coefficient (r) was used to examine validity. Effects were evaluated using non-clinical magnitude based inference. There was almost perfect agreement between instruments (ICC = 0.999?1.000, most likely positive 100/0/0). Paired t-test showed a mean difference of 0.03 ± 0.21 cm (90% CI -0.04 ? -0.01) between instruments (most likely trivial 0/100/0). Both instruments showed very good stability (? = 1.00, CV = 4.28±1.95%). The smallest worthwhile change and typical error values were 1.3 and 0.29 cm, respectively and therefore, the signal-to-noise ratio of both instruments was large: 4.5. Finally, almost perfect correlation between instruments was observed (r = 0.999, most likely positive 100/0/0). Chronojump can be regarded as a sensitive instrument to detect changes in jump height performance over the possible noise around the measure. The results supported the open-source jump mat to be a useful, valid and reliable, low-cost testing device to monitor variations in vertical jumping performance

Concurrent Validity of the Inertial Measurement Unit Vmaxpro in Vertical Jump Estimation

The aim of this study was to evaluate if the inertial measurement unit (IMU) Vmaxpro is a valid device to estimate vertical jump height (VJH) when compared to a motion capture system (MoCAP). Thirteen highly trained female volleyball players participated in this study which consisted of three sessions. After a familiarization session, two sessions comprised a warm-up followed by ten countermovement jumps, resting two min between each attempt. Jump height was measured simultaneously by Vmaxpro using take-off velocity and MoCAP using center-of-mass vertical excursion. Results show significant differences in jump height between devices (10.52 cm; p < 0.001; ES = 0.9), a very strong Spearman’s correlation (rs = 0.84: p < 0.001), and a weak concordance correlation coefficient (CCC = 0.22; ρ = 0.861; Cb= 0.26). Regression analysis reveals very high correlations, high systematic error (8.46 cm), and a nonproportional random error (SEE = 1.67 cm). Bland–Altman plots show systematic error (10.6 cm) with 97.3 % of the data being within the LoA. In conclusion, Vmaxpro can be considered a valid device for the estimation of VJH, being a cheaper, portable, and manageable alternative to MoCAP. However, the magnitude of systematic error discourages its use where indistinguishable data from Vmaxpro and MoCAP are used unless the corresponding specific fitting equation is applied.This work was supported by Generalitat Valenciana (grant number GV/2021/098)

Reliability of My Jump 2 Derived from Crouching and Standing Observation Heights

The crouching or prone-on-the-ground observation heights suggested by the My Jump app are not practical in some settings, so users usually hold smartphones in a standing posture. This study aimed to analyze the reliability of My Jump 2 from the standardized and standing positions. Two identical smartphones recorded 195 countermovement jump executions from 39 active adult athletes at heights 30 and 90 cm, which were randomly assessed by three experienced observers. The between-observer reliability was high for both observation heights separately (ICC~0.99; SEM~0.6 cm; CV~1.3%) with low systematic (0.1 cm) and random (±1.7 cm) errors. The within-observer reliability for the three observers comparing the standardized and standing positions was high (ICC~0.99; SEM~0.7 cm; CV~1.4%), showing errors of 0.3 ± 1.9 cm. Observer 2 was the least accurate out of the three, although reliability remained similar to the levels of agreement found in the literature. The reliability of the mean observations in each height also revealed high reliability (ICC = 0.993; SEM = 0.51 cm; CV = 1.05%, error 0.32 ± 1.4 cm). Therefore, the reliability in the standing position did not change with respect to the standardized position, so it can be regarded as an alternative method to using My Jump 2 with practical added benefits.This research was funded by Generalitat Valenciana, grant number GV/2021/098

Digger’s activity at men’s European Beach Volleyball University Championship

In this paper, we present a study of digger activity among university beach volleyball players. A total of 929 digger actions carried out by 24 European University teams at the 9th European Beach Volleyball Championship EUSA GAMES were analyzed. The video was analyzed using Longomatch v.0.27 software. Statistical significance of the comparison between systems was calculated using the Z test to compare proportions. Results showed that 63.8% were passive actions and 36.2% were active actions (p<0.001) while 51% of digger actions were in static position and 49% in dynamic position (p=0.178). Furthermore, 23.1% of digger actions ended in counter attack and 76.9% ended without counter attack (p<0.001). As a result, the most effective defence can be considered to be static actives. This study leads to specific training of defensive actions and lays the foundation for specialized training for diggers