Impact of hockey skate design on ankle motion and force production

The Relationship Between Lower-Body Force-Time Variables and Skating Performance in Female Ice Hockey Players

PURPOSE

Ice hockey is a team invasion sport characterized by repeated high-intensity skating efforts, technical and tactical skill, physical contact, and collisions requiring considerable levels of muscular strength. The purpose of this study was to evaluate the relationships between lower-body vertical force-time metrics and skating qualities in subelite female ice hockey players.

METHODS

A cross-sectional cohort design was employed utilizing 14 athletes (body mass = 66.7 [1.8] kg; height = 171.6 [6.2] cm; age = 21.1 [1.7] y). The relationships between metrics of lower-body strength collected from a drop jump, squat jump, countermovement jump, loaded countermovement jump, and an isometric squat and 4 skating qualities collected from a linear sprint, repeated sprint test, and a multistage aerobic test were evaluated.

RESULTS

The regression models revealed a positive relationship between relative peak force in the isometric squat and skating multistage aerobic test performance (r2 = .388; P = .017) and a positive relationship between repeated-sprint ability and eccentric mean force during the loaded countermovement jump (r2 = .595; P = .001). No significant relationships were observed between strength metrics and skating acceleration or maximal velocity.

CONCLUSIONS

These data suggest that skating ability is most affected by relative isometric strength in female ice hockey players. It is recommended that practitioners focus training on tasks that improve relative force output. It is also recommended that isometric relative peak force be used as a monitoring metric for this cohort.

Mechanical determinants of forward skating sprint inferred from off- and on-ice force-velocity evaluations in elite female ice hockey players

This study aimed to investigate the correlations between players' mechanical capacities determined during off- and on-ice tests. Whole body force-velocity relationships were assessed in elite female ice hockey players (n = 17) during jumping [squat jump (SJ)], running (5 and 30 m) and skating (5 and 40 m) sprint tasks. Mechanical capacities estimates include relative maximal theoretical force (F_0rel), velocity (V₀), power (P_maxrel), slope of the linear relationship between force relative to body mass and velocity (S_FVrel), maximal horizontal component of the ground reaction force to the corresponding resultant force (RF_max) and minimal rate of decrease of this ratio (D_RF). On-ice mechanical capacities (F_0rel, P_maxrel, RF_max and D_RF) largely-to-very largely correlated with 40-m skating split time (r ranging from 0.82 for D_RF to -0.91 for P_maxrel; p < 0.001). Performance variables (SJ height, 30-m running and 40-m forward skating split time) and P_maxrel demonstrated the largest associations between jumping, running and skating tasks (r ranging from -0.81 for 30-m sprint running time to 0.92 for SJ height; p < 0.001). Small (V₀, S_FVrel, D_RF and force-velocity deficit) to very large (P_maxrel) correlations (r ranging from 0.58 to 0.72; p < 0.05) were obtained between mechanical variables inferred from off- and on-ice force-velocity tests. The capacity to generate high amounts of horizontal power and effective horizontal force during the first steps on the ice is paramount for forward skating sprint performance. Mechanical capacities determined during forward skating sprint could be considered in ice hockey testing to identify fitness and/or technical/training requirements.

Principal component analysis identifies differences in ice hockey skating stride between high- and low-calibre players

The objective was to compare joint angles during full stride skating on ice between high- and low-calibre hockey players. High (n = 8) and low (n = 8) calibre male participants completed full stride skating on ice for two to five trials. A 10-camera motion capture system collected kinematic data. Ankle, knee, and hip angles were calculated. Principal component analysis (PCA) identified important angle characteristics and each trial was scored against principal components (PC-scores). Hierarchical linear models examined relationships between PC-scores and skill level with and without controlling for speed. High-calibre participants were associated with greater ankle inversion during push-off and recovery (p < 0.001), greater knee extension (p = 0.051) and external rotation at push-off (p = 0.038), and greater hip flexion throughout stride (p = 0.027) after controlling for speed. Interactions existed between speed and skill level including faster skating speeds were associated with increased plantarflexion at push-off in low-calibre participants while there was no relationship in high-calibre participants. Skating pattern differences between skill levels provide an indication of ideal joint motion during skating. Players should be encouraged to plantarflex the ankle during push-off, extend and externally rotate the knee during push-off, and increase hip flexion throughout stride.

biomechZoo: An open-source toolbox for the processing, analysis, and visualization of biomechanical movement data

It is common for biomechanics data sets to contain numerous dependent variables recorded over time, for many subjects, groups, and/or conditions. These data often require standard sorting, processing, and analysis operations to be performed in order to answer research questions. Visualization of these data is also crucial. This manuscript presents biomechZoo, an open-source toolbox that provides tools and graphical user interfaces to help users achieve these goals. The aims of this manuscript are to (1) introduce the main features of the toolbox, including a virtual three-dimensional environment to animate motion data (Director), a data plotting suite (Ensembler), and functions for the computation of three-dimensional lower-limb joint angles, moments, and power and (2) compare these computations to those of an existing validated system. To these ends, the steps required to process and analyze a sample data set via the toolbox are outlined. The data set comprises three-dimensional marker, ground reaction force (GRF), joint kinematic, and joint kinetic data of subjects performing straight walking and 90° turning manoeuvres. Joint kinematics and kinetics processed within the toolbox were found to be similar to outputs from a commercial system. The biomechZoo toolbox represents the work of several years and multiple contributors to provide a flexible platform to examine time-series data sets typical in the movement sciences. The toolbox has previously been used to process and analyse walking, running, and ice hockey data sets, and can integrate existing routines, such as the KineMat toolbox, for additional analyses. The toolbox can help researchers and clinicians new to programming or biomechanics to process and analyze their data through a customizable workflow, while advanced users are encouraged to contribute additional functionality to the project. Students may benefit from using biomechZoo as a learning and research tool. It is hoped that the toolbox can play a role in advancing research in the movement sciences. The biomechZoo m-files, sample data, and help repositories are available online (http://www.biomechzoo.com) under the Apache 2.0 License. The toolbox is supported for Matlab (r2014b or newer, The Mathworks Inc., Natick, USA) for Windows (Microsoft Corp., Redmond, USA) and Mac OS (Apple Inc., Cupertino, USA).