# Assessing High-Intensity Acceleration Efforts Using Local Positioning System—Introducing the Concept of the Relative Acceleration Threshold to Ice Hockey

## TL;DR

This paper introduces a new method to assess high-intensity acceleration efforts in ice hockey by adjusting for initial skating speed, leading to more accurate evaluations.

## Contribution

The novel contribution is the introduction of the relative acceleration threshold (relthreshold) to account for initial skating speed in assessing acceleration efforts.

## Key findings

- The fixthreshold_2 method reported significantly more accefforts than the relthreshold_75% method.
- Only one-third of accefforts identified by fixthreshold_2 exceeded the neuromuscularly intense threshold defined by relthreshold_75%.
- The relthreshold_75% method assessed a notable percentage of accefforts at high skating speeds where fixthreshold_2 failed.

## Abstract

Current methods for assessing acceleration efforts (accefforts) in ice hockey do not account for the influence of initial skating speed on maximal voluntary acceleration capacity, which may lead to a biased evaluation of acceffort intensity. In this study, we introduce the conceptual approach of the relative acceleration threshold (relthreshold) to ice hockey and outline its potential benefits for the assessment of accefforts. Locomotion data derived from observations of 17 players across 10 official games were used to model the initial-skating-speed-dependent maximal voluntary acceleration capacity (amax–vinit capacity), from which a team-specific relthreshold was determined (relthreshold_75% = 3.23 − 0.365vinit), and, subsequently, applied to assess accefforts alongside a fix threshold set at 2 m·s−2 (fixthreshold_2). Differences in accefforts depended on the method used (relthreshold_75% vs. fixthreshold_2) as well as the playing position when using the relthreshold_75%. The fixthreshold_2 reported 89.1 ± 35.8% more accefforts than the relthreshold_75%. However, only one-third of these accefforts exceeded relthreshold_75%, which is considered indicative of neuromuscularly intense accefforts according to the modeled amax–vinit capacity. Moreover, at skating speeds above 4 m·s−1, the fixthreshold_2 only assessed a negligible number of accefforts, whereas the relthreshold_75% assessed 27.2 ± 9.3% of all its accefforts. In line with established theoretical rationales, the observational findings of this study suggest that an acceleration threshold adapted to the initial skating speed offers a conceptually more valid approach to assessing accefforts in ice hockey.