A continuous times-series and discrete measure analysis of two individual divers performing the 3½ pike somersault dive.

Springboard diving training is often focused upon skill repetition to establish movement accuracy, stability and consistency. Within-participant study designs provide the ability to understand how individuals create these skills under different movement strategies. IMUs measured angular velocity time-series data of two athletes performing multiple repetitions of forward 3½ somersault pike dives. Functional Principal Component Analyses (fPCA) were performed to examine individual movement structure and variability. The first five fPC's represented approximately 98% of the variability in angular velocity for both divers. To determine the relative importance of angular velocity variability, Pearson's correlations for pairwise comparisons were used to assess the relationship between fPC scores and discrete performance variables during takeoff, flight and entry. Divers exhibited a different number and types of significant correlations (International = 4; National = 11). Only one correlation was common for both divers; higher angular velocity during Initial Flight and/or Somersault phases resulted in more vertically aligned entry posture (International: fPC1 r = -0.761, p < 0.05; National: fPC3 r = -0.796, p < 0.01). Findings identify individualised angular velocity time-series structure and kinematic performance variables (International = angular; National = linear) that can be used by coaching/sport science teams to optimisation performance success.

Is acrobatic pyramid performance determined by the individual balance of the gymnasts?

The influence of individual gymnasts' balance on final pyramid performance is unknown. The principal objective of this study was to evaluate associations between the balance capacity of base and top gymnasts (BG, BT) on the pyramid performance using different balance tasks. Forty acrobatic gymnasts were divided in two groups (20 BG, 20 TG) and performed three different static tests on a force platform: unipedal (open and closed eyes), and headstand. Centre of pressure (COP) measurements were obtained including length travelled in the anteroposterior and mediolateral axis, surface area and the mean speed. Pairs of gymnasts performed a pyramid which involved the BG standing upright while holding a TP in handstand with arms flexed at the elbow. Pyramid scores were obtained from judges to assess the performance. Principal component analysis (PCA) was used to reduce the number of balance COP variables. Linear regression analysis was applied with pyramid performance and scores of PCA separated by role. TG's PCA 2 was a significant predictor of pyramid performance. Higher pyramid performance was associated with better headstand balance capacity in TG. The results suggest that measuring COP displacement during headstands could help coaches and gymnasts to assess the handstand pyramid performance.

Static balance performance differs depending on the test, age and specific role played in acrobatic gymnastics.

BACKGROUND: Static balance performance appears to detect differences between roles played in team sports. Static balance can also be influenced by the subject's height and age, and the type of test used. RESEARCH QUESTION: Could the static balance profile show differences among the role played depending on the specific test evaluated and the gymnasts' age? METHODS: A cross-sectional design was applied. 46 acrobatic gymnasts (37 females and 9 males) were divided in four groups according to role (base or top gymnast) and stage of adolescence (early adolescent or mid-adolescent) during two different static tests: (1) unipedal with open and closed eyes (generic), and (2) headstand (specific). To test the effect of the role and the age group, a two-way analysis of variance (ANOVA) between groups was performed. Centre of pressure (COP) measurements were obtained and normalised relative to participants height, including length travelled on the anteroposterior and mediolateral axis (AP_CoP and ML_CoP) and the mean speed (SP_CoP). RESULTS: Base gymnasts obtained lower values in the CoP excursion than Top gymnasts but only in unipedal tests for all the variables analysed (5.536 ≥ F1,42 ≤ 10.589, 0.002 ≥ p ≤ 0.023), except for the AP_CoP in unipedal-closed. Mid-adolescent gymnasts obtained lower values in the CoP excursion regardless of the task than early adolescent (5.324 ≥ F1,42 ≤ 14.805, 0.000 ≥ p ≤ 0.026). SIGNIFICANCE: It has been observed a clear effect of age on the static balance manifested in acrobatic gymnastics, regardless of the subject's height, the role played, and the test performed. The effect of the role played in this team sport has been different depending on the type of test performed.

The application of inertial measurement units and functional principal component analysis to evaluate movement in the forward 3½ pike somersault springboard dive.

Based on technological and analytical advances, the capability to more accurately and finitely examine biomechanical and skill characteristics of movement has improved. The purpose of this study was to use Inertial Measurement Units (IMUs) and Functional Principal Components Analysis (fPCA) to examine the role of movement variability (assessed via angular velocity), on 2 divers (1 international level; 1 national) performing the forward 3½ pike somersault dive. Analysis of angular velocity curves during ive-flight identified 5 fPCs, accounting for 96.5% of movement variability. The national diver's scatter plots and standard deviation of fPC scores illustrated larger magnitudes of angular velocity variability across dive flight. For fPC1 and fPC3, magnitudes of SD variability were 282.6 and 201.5, respectively. The international diver illustrated more consistent angular velocity profiles, with clustering of fPCs scores (e.g., fPC1 & 3 = SD's of 75.2 & 68.0). To account for lower variability in the international diver, the ability to better coordinate movement sequences and functionally utilise feedback in response to initiation of the somersault position is highlighted. Overall, findings highlight how both IMUs and fPCA can more holistically and finitely examine the biomechanical and skill characteristics of movement sequences with the capability to inform athlete development.

The validation and application of Inertial Measurement Units to springboard diving.

Inertial Measurement Units (IMUs) may offer an ecologically valid, reliable, and practical method for biomechanical performance analysis. With such potential in mind, Part 1 of this study examined the accuracy of IMUs gyroscopes with an optical system (Cortex 3.3). A calibration formula standardised the IMUs angular velocity output with the optical system. The percentage differences between the two measures = 0.5% (p < 0.05), suggest IMU's efficacy for application. In Part 2, the aim was to examine and understand how dive flight angular velocity time series plots change and increase according to dive degree of difficulty. With IMUs attached to three competitive divers performing forward somersault dives, dive flight kinematics were assessed. Biomechanically, a 4½ tuck somersault dive differed to lower degree of difficulty dives in terms of: (1) a rotational delay immediately after takeoff (to gain greater vertical translation); (2) increased total time of flight; (3) greater muscle effort to resist increased centrifugal forces produced by the increased angular velocity (1,090 °/s); and (4) greater eccentric control during deceleration allow a safe and vertical entry into the water. IMUs can be effectively utilised and integrated into contexts such as springboard diving for performance analysis and optimisation purposes.