Kinematic analysis of basic rhythmic movements of hip-hop dance: motion characteristics common to expert dancers

Injury, Training, Biomechanical, and Physiological Profiles of Professional Breakdancers

Background

Breakdancing or breaking will enter the Olympics in 2024, however, there is a paucity of literature exploring the epidemiology, demands, and performance.

Purpose

The purpose of this study was to describe injury and training profiles, along with the results of a short performance test battery, in a group of elite breakers.

Study Design

Cross-sectional study (retrospective).

Methods

Fourteen breakdancers (breakers) (4 Bgirls, 10 Bboys) participated in an interview regarding their injury and training history, endurance test (cycle VO2max testing), counter movement jump, squat jump, drop jump, isometric hip abduction, adduction, shoulder external and internal rotation strength testing on a fixed-frame dynamometer. Breakers were divided into elite (n=10) and developing (n=4) based on their qualification for a world finals competition; Wilcoxen rank sums were used to compare the two groups, or in the case of strength testing between those with and without an injury history.

Results

The breakers had a median 11.0 [10.0 - 14.0] years breaking experience and trained 24.4 [20.5 - 30.0] hours per week. The knee was the most commonly injured body part and most frequently injured joint, with the thigh being the most common site for muscle injuries. There were no differences in endurance testing or jump height testing results between elite and developing breakers. There was no difference in shoulder external or internal rotation strength between athletes with a history of shoulder injury and those without. Similarly, there was no difference in hip abduction or adduction strength in those with a history of hip injury and those without.

Conclusion

The results of this study should be viewed with caution due to the small sample size. However, this study is the first to publish functional and physiological descriptives on breakers. The authors hope these results support clinicians treating breakers as well as encourages future research related to breaking.

Level of Evidence

2b.

Kinematic Motor Synergy Analysis to Understand Lock Dance Choreographies

Lock dance, or locking, is one of the popular old-school street dance styles featuring sharp, sudden, and isolated body movements through intricate control and coordination of joints and muscles. This work aims to understand the complex lock dance motions based on kinematic motor synergy analysis. Lock dance motions performed by three experienced dancers were measured with a markerless human motion capture technique. The motor synergies were identified and summarized using principle component analysis (PCA). The motion complexity, joint contributions, and motor coordination of ten basic lock dance choreographies were analyzed based on the synergy patterns and their activations. The results enhance our understanding of complex dance motions and serve as a step toward future applications to, e.g. dance skill or injury risk assessments.

Analysis of Main Movement Characteristics of Hip Hop Dance Based on Deep Learning of Dance Movements

In order to explore the main action characteristics of hip hop dance, a deep learning recognition system based on dance action is proposed. The network is based on convolution, pooling, and full connection calculation in a convolutional neural network (CNN). On the one hand, the pixel information in the video frame is extracted as the network input feature in the spatial domain. On the other hand, in the time domain, in order to better represent the change characteristics of video actions, optical flow information is introduced, and the optical flow vector change of pixels in DT time is calculated by the pyramid algorithm (LK) as the time domain convolution feature. In order to evaluate the performance of the network, this article takes the recognition of dance movements as an example to test the application of the algorithm. The test dataset contains 101 fully identified dance movements. The test results show that the proposed algorithm is 10.90% higher than F1 of inception V3, and the recognition accuracy is 10.85% and 5.27% higher than that of inception V3 and 3D-CNN networks, respectively. For the problems and difficulties brought by single-mode video action recognition, a multimodal action recognition method is introduced to achieve better results based on a large number of training data. Different depth networks have different characteristics. CNN network pays more attention to the relationship between local information, so it is suitable for image recognition and detection tasks. The RNN network is expanded in the time dimension, so it is suitable for the modal information related to similar videos. Therefore, based on multimodal information and a depth neural network, a depth feature extraction and fusion method for multimodal information is designed. Different methods of feature extraction and fusion are tried in the experiment, and the experimental results are analyzed. It proves that the deep learning and recognition of dance movement can effectively explore the main movement characteristics of hip hop dance.

Dance-based exergaming on postural stability and kinematics in people with chronic stroke - A preliminary study

INTRODUCTION

The study evaluated the feasibility, and compliance of a dance-based exergaming (DBExG) on postural stability (PS) and lower extremity (LE) kinematics, along with post-intervention changes in gait function and falls self-efficacy in people with chronic stroke (PwCS).

METHODS

Fifteen PwCS underwent DBExG for six weeks using Kinect "Just Dance 3." Pre- to post- changes were recorded during DBExG assessment on a fast-paced song (130 bpm) using an 8-camera motion capture system to assess PS (center of mass [CoM] excursions [EXs] in the anterior-posterior [AP] and mediolateral [ML] directions) and LE kinematics (hip, knee, and ankle joint angle EXs). Gait function was also assessed with gait parameters, such as gait speed, cadence, and gait symmetry on an electronic walkway. Falls self-efficacy was recorded with Falls Efficacy Scale (FES).

RESULTS

The AP and ML CoM EXs and paretic joint angle EXs significantly increased pre- to post- DBExG assessment (p < .05). Gait parameters, and falls self-efficacy measures significantly changed pre- to post- DBExG (p < .05).

CONCLUSIONS

Results exhibited the feasibility of the proposed DBExG for positively impacting postural stability, and kinematics, along with increasing gait function and falls self-efficacy among PwCS.

Individual Differences in Sequential Movement Coordination in Hip-Hop Dance: Capturing Joint Articulation in Practicing the Wave

The current study highlights individual differences in the joint articulation strategies used by novices practicing a hip-hop dance movement, the wave. Twelve young adults, all naive regarding hip-hop dance performance, practized the wave in 120 trials separated into four blocks with the order of internal or external attentional focus counterbalanced across subjects. Various kinematic analyses were analyzed to capture performance success while exploiting the observed individual differences in order to establish the reliability of the proposed performance indicators. An external focus of attention marginally facilitated the smooth transfer of a wave motion across neighboring limb segments as characterized by a constant propagation speed combined with large wave amplitudes. Systematic correlations between the success indicators were found, exemplifying the various degrees of joint articulation that novices prove capable of during an initial practicing session to try and perform a novel complex motor task.

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

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.

Injury Occurrence in Modern and Hip-Hop Dancers: A Systematic Literature Review

Introduction

Dance-related injuries have become a field of great interest to researchers, with the most commonly reported injuries being those sustained by ballet dancers. However, there is a lack of research into injuries sustained by those who perform modern and hip-hop dance.

Methods

A systematic literature review using the MEDLINE research database was performed and a search carried out for full-text studies that investigate injuries in modern and hip-hop dance.

Results

While a total of 74 hits were obtained from various searches, only nine studies were included in the systematic literature review. Six of them examined modern dancers, two examined break dancers and one examined hip-hop dancers. The results show that hip-hop dancers (and especially break dancers) sustain more injuries in comparison to modern dancers. The most common injuries are in the lower extremities, with studies revealing that overuse injuries occur in up to 71% of cases.

Conclusions

The injury incidence rate in hip-hop dance seems to be higher compared to modern dance, chiefly because of the more demanding biomechanics involved and the dance techniques employed. Prevention management can have a positive effect on the number of injuries.

Influence of adapted hip-hop dancing on quality of life and social participation among children/adolescents with cerebral palsy

OBJECTIVE

To describe the influence of adapted hip-hop dancing on the quality of life (QoL) and biopsychosocial profile of children/adolescents with cerebral palsy (CP).

METHODS

Pilot study including 18 children/adolescents with CP and Gross Motor Function Classification System levels I and II. Nine participants took part in an adapted hip-hop dance practice (study group; SG), and nine others served as the control group (CG). All participants were assessed with the Pediatric Outcomes Data Collection Instrument and the Child Behavior Checklist at baseline and after at least three months of dance practice and a public performance (SG) or a similar period without intervention (CG).

RESULTS

Improvement in QoL was observed in the SG in the domains of transfer and basic mobility (p = 0.00*), sporting and physical function (p = 0.04*), and global function and symptoms (p = 0.01*). In the SG, there was a reduction in emotional and behavioral problems and an increase in social competence in the biopsychosocial profile. Greater participation in adapted hip-hop dancing was associated with a greater gain in the transfer and basic mobility domains (p = 0.05*) of the Pediatric Outcomes Data Collection Instrument and in the activities (p = 0.05*) and social (p = 0.04*) scales of the Child Behavior Checklist.

CONCLUSIONS

Children/adolescents with CP participating in adapted hip-hop dance practice showed improvement in QoL and biopsychosocial profile scores.

Investigating the Prevalence and Predictors of Injury Occurrence in Competitive Hip Hop Dancers: Prospective Analysis

Hip hop is a popular form of competitive and recreational sport worldwide, but studies rarely investigate injury prevalence and factors associated with injury occurrence in this sport. This study aimed to prospectively examine injury occurrence in hip hop dancers in a three-month period and to evaluate potential predictors of injury occurrence in hip hop dancers. The participants were 129 competitive hip hop dancers (114 females, 17.95 ± 4.15 years of age). Study predictors were obtained at study baseline and included sociodemographic factors, sport-related factors, previous injury status, anthropometric and body build indices (body height, mass, body mass index, and body composition variables), and dynamic balance performance (obtained by the Star Excursion Balance Test—SEBT). The outcome was injury occurrence, which was prospectively observed once a week by the Oslo Sports Trauma Research Center Overuse Injury Questionnaire (OSTRC). During the course of the study, 101 injuries occurred, equating to an annual injury incidence of 312%. On average, each dancer suffered 0.78 injuries (95% Confidence Interval (95% CI): 0.61–0.97) across a study period of three months (0.76 (95% CI: 0.60–0.95) and 0.93 (95% CI: 0.75–1.13), in females and males, respectively; Mann Whitney Z-value: 0.68, p = 0.52). Seventeen percent of dancers suffered multiple injuries, and 49% of all injuries were time-loss injuries. The knee was the most frequently injured body location (42% of all reported injuries), followed by the back region (32%) and the ankle (15%). Previous injury was a strong predictor of injury occurrence (Odds Ratio: 3.76, 95% CI: 1.87–4.59). Lower injury risk was evidenced among those participants who achieved better scores on several SEBT variables, irrespective of gender and previous injury status; with no significant influence of anthropometric and body build variables on injury occurrence. This study highlighted a high injury rate in hip hop dancers. Dancers and coaches should be informed about the certain protective effects of dynamic balance on the prevention of musculoskeletal injury in hip hop in order to assure safe and effective practices. The usage of SEBT as a convenient and cheap testing procedure is encouraged in other dance disciplines.

Key motion characteristics of side-step movements in hip-hop dance and their effect on the evaluation by judges

In hip-hop dance, the elements of motion that discriminate the skill levels of dancers and that influence the evaluations by judges have not been clearly identified. This study set out to extract these motion characteristics from the side-step movements of hip-hop dancing. Eight expert and eight non-expert dancers performed side-step movements, which were recorded using a motion capture system. Nine experienced judges evaluated the dancers' performances. Several parameters, including the range of motion (ROM) of the joint angles (neck, trunk, hip, knee, and face inclination) and phase delays between these angular motions were calculated. A quarter-cycle phase delay between the neck motion and other body parts, seen only in the expert dancers, is highlighted as an element that can distinguish dancers' skill levels. This feature of the expert dancers resulted in a larger ROM during the face inclination than that for the non-expert dancers. In addition, the experts exhibited a bottom-to-top segmental sequence in the horizontal direction while the non-experts did not demonstrate any such sequential motion. Of these kinematic parameters, only the ROM of the face inclination was highly correlated to the judging score and is regarded as being the most appealing element of the side-step movement.