RELIABILITY OF THE EVALUATION OF HUMANOID ANIMATION AS A VISUALIZING TOOL IN HIP-HOP DANCE

The purpose of this study was to determine the reliability of the evaluation the humanoid animation by comparing the intra and inter-rater reliability between humanoid animation and stick figure animation of hip-hop dance. The humanoid animation and the stick figure animation were created using motion capture data from 16 hip-hop dancers. Five judges were asked to evaluate the 32 dance trials and they were not informed that they were repeating an evaluation. The intra-class correlation coefficient of the humanoid animation demonstrated very high reliability and was higher than the stick figure animation. There was no difference between the animations in the inter-class correlation coefficient. Humanoid animation may provide a more reliable method for the evaluation of dance movements as a feedback tool

Judges’ evaluation reliability changes between identifiable and anonymous performance of hip-hop dance movements

© 2021 Sato, Hopper. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Hip-hop competitions are performed across the world. In the recent inclusion in the 2018 Youth Olympic Games, the assessment of hip-hop performance is undertaken by a panel of judges. The purpose of this study was to determine the reliability of different visualisation tools utilised in the assessment of the hip-hop dance movements. Ten dancers performed basic rhythmic hip-hop movements which were captured using a motion capture system and video camera. Humanoid and stick figure animations of the dancers’ movements were created from the motion capture data. Ten judges then assessed 20 dance trials through observation using three different visualisation tools on a computer display, each of which provided different representations of a given hip-hop performance: (1) the actual video of the dancers; (2) an anonymous stick figure animation; (3) an anonymous humanoid animation. Judges were not informed that they were repeating an assessment of the performances across the three visualisation tools. The humanoid animation demonstrated the highest inter-class correlation coefficients among the three methods. Despite the stick figure animation demonstrating moderate to high reliability, both the humanoid animation and the video demonstrated very high reliability in the intra-class correlation coefficient. It is recommended that further research is undertaken exploring the use of humanoid animation as a formative assessment tool in the evaluation of hip-hop dance and the evolution of hip-hop into a respected artistic athletic discipline

MOTION CHARACTERISTICS AFFECT EVALUATION BY JUDGES IN HIP-HOP DANCE: KINEMATIC ANALYSIS OF STEP MOVEMENT

The purpose of this study was to extract motion characteristics closely related to high evaluation by judges, through a comparison of “side-step” movement between eight expert and eight non-expert dancers. Their step motions were captured and the head trajectory relative to the centre of mass, face inclination, and time lags among neck, trunk, hip and knee angles were calculated. As a result, a quarter cycle of phase delay between the neck motion and other body parts were observed for the expert dancers. This delay resulted in a large displacement of the head relative to the centre of mass and a large range of motion of the face inclination. The face inclination was highly correlated with the judging score (r = 0.869). Thus, it is assumed these motion characteristics are the most important element of the side-step movement that induces a better impression of judges

Kinematic repeatability analyses of multi-segment foot motion in university-level ballet dancers

Background: Dancers are susceptible to overuse foot and ankle injuries, however there is a lack biomechanical studies examining foot mechanics to explain the causality of these injuries. The purpose of this study was to determine the intra and inter-assessor repeatability of a modified Rizzoli Foot Model (RFM) for ballet dancers. Methods: Six university-level ballet dancers performed the following trials in randomized order, natural stance, turnout plié and stance, and two dynamic trials; turnout rise and flex-point-flex movement. A twelve-camera motion capture system were used to track fourteen reflective markers and one triad on the following segments: shank, entire foot, hindfoot, midfoot, forefoot and hallux. A repeated-measure design was used with each participant undergoing four data collection sessions; i.e. two sessions were conducted by each researcher over two consecutive days. Variability of the 3D segment rotations and planar angles were determined using intra-class correlation coefficients (ICC) for the intra and inter-assessor repeatability. Results: Intra and inter-assessor reliability demonstrated excellent (ICC ≥ 0.75) reliability for 1st metatarsophalangeal joint sagittal plane measurements. Intra-assessor variability demonstrated excellent (ICC ≥ 0.75) reliability in the sagittal plane and frontal planes for all the discrete static variables, except the midfoot-forefoot articulation which was in the sagittal and transverse planes. Whereas the inter-assessor variability revealed fair to good repeatability (0.5 ≤ ICC \u3c 0.75). The trend towards a lower inter-assessor repeatability indicates the lack of training of the marker placement protocol. A similar trend was found in the repeatability in the dynamic trials. Intra and inter-assessor reliability demonstrated excellent (ICC ≥ 0.75) reliability for 1st metatarsophalangeal joint sagittal plane measurements. Intra-assessor variability demonstrated excellent (ICC ≥ 0.75) reliability in the sagittal and frontal planes for all the discrete static variables, except the midfoot-forefoot articulation which was in the sagittal and transverse planes. Inter-assessor repeatability revealed large variability from poor to excellent (0.5 \u3e ICC ≥ 0.75) repeatability for the 3D segmental rotations. Conclusion: Three-dimensional multi-segment foot models have the potential to be reliably used in dance screenings to ascertain whether technical errors and/or biomechanical abnormalities are the cause of a dancers’ lower limb overuse injury. However, research laboratories should develop good marker placement protocol to endeavour to produce repeatable between assessor results.https://ro.ecu.edu.au/ecuposters/1024/thumbnail.jp

MOTION CHARACTERISTICS IN HIP HOP DANCE UNDERLYING SUBJECTIVE EVALUATION OF THE PERFORMANCE

The purpose of this study was to extract the motion characteristics that are closely related to the subjective evaluation of hip hop dance performance. The subjects were 11 expert, six non-expert and nine novice hip hop dancers. Each dancer performed the “wave“ motion as the experimental task. Movements of upper extremities during the task were captured by a motion capture system and several kinematic parameters including the propagation velocity of the wave (PV) were calculated. We found that the coefficient of variance of the PV was highly correlated with the subjective evaluation by the judges (r=0.770,

ELASTIC TAPING APPLIED TO THE RECTUS FEMORIS MUSCLE ALTERS INSTEP KICKING KINEMATICS IN SOCCER

We aimed to clarify the immediate effect of an elastic taping application on the kinematics of soccer instep kicking. Fourteen male university recreational soccer players performed maximal instep kicking with and without an elastic taping applied to the rectus femoris muscle, and their kicking motions were captured using a motion capture system at 500Hz. Prior to the kicking session, the thickness of the rectus femoris muscle was measured using an ultrasound scanner. The elastic taping application significantly increased the thickness of the rectus femoris muscle. Alongside this change, initial ball velocity, peak hip flexion angular velocity, and foot linear velocities increased significantly, whereas knee extension angular velocity and hip linear velocity did not change. It is considered that the elastic taping application may enhance the function of the rectus femoris muscle, thereby inducing these kinematic changes during kicking. These findings suggested that an elastic taping application may be an effective tool to improve the performance of soccer instep kicking

Single-leg squats can predict leg alignment in dancers performing ballet movements in turnout

The physical assessments used in dance injury surveillance programs are often adapted from the sports and exercise domain. Bespoke physical assessments may be required for dance, particularly when ballet movements involve “turning out” or external rotation of the legs beyond that typically used in sports. This study evaluated the ability of the traditional single-leg squat to predict the leg alignment of dancers performing ballet movements with turnout. Three-dimensional kinematic data of dancers performing the single-leg squat and five ballet movements were recorded and analyzed. Reduction of the three-dimensional data into a one-dimensional variable incorporating the ankle, knee, and hip joint center positions provided the strongest predictive model between the single-leg squat and the ballet movements. The single-leg squat can predict leg alignment in dancers performing ballet movements, even in “turned out” postures. Clinicians should pay careful attention to observational positioning and rating criteria when assessing dancers performing the single-leg squat

A COMPARISON OF BASIC RHYTHM MOVEMENT KINEMATICS BETWEEN EXPERT AND NON-EXPERT HIP HOP DANCERS

Common motion characteristics that may be linked to higher judging evaluations of hip hop dance were investigated. A comparison of the rhythmic movement between ten expert and twelve non-expert dancers was undertaken. Trajectory data was captured using a motion capture system at 120 Hz and kinematic parameters including the time lags of occurrence of peak joint angle in neck, trunk, hip and knee joint were calculated. Smaller time lags between neck and other joints were observed in the expert dancers. Furthermore, the neck motion was delayed for approximately a quarter cycle of the basic rhythm compared with the half cycle delay observed in the non-expert group. Timing differences in the coordination of joint angles is the most likely a factor to explain the higher judging evaluations awarded to the expert dancers

CONTRIBUTION OF THE SUPPORT LEG TO ACCELERATE KICKING LEG SWING DURING SOCCER INSTEP KICKING

The present study aimed to determine the contribution of support leg motion to the acceleration of the kicking leg in soccer instep kicking. The kicking motion was recorded by a motion capture system. According to the procedures proposed in previous studies, the power due to the muscle and interaction moments acting on the kicking lower leg was computed. The forward swing of the lower leg during the final phase of kicking was dominated by the power of the interaction moment rather than by that of the muscle moment. The support leg motion contributed to produce more than 50 % of the total amount of positive work due to the power of the interaction moment. The present study proposed a reasonable mechanism for the acceleration of the lower leg swing when its angular velocity exceeds the inherent force-velocity limitation of muscles