Change of Direction and Agility Tests: Challenging Our Current Measures of Performance Study Notes

Change of Direction and Agility Tests: Challenging Our Current Measures of Performance

Authors: Sophia Nimphius, PhD, Samuel J. Callaghan, BSc (Honours), Neil E. Bezodis, PhD, Robert G. Lockie, PhD
Affiliations:

  1. Centre for Exercise and Sports Science Research, School of Medical and Health Sciences, Edith Cowan University, Joondalup, Australia
  2. Softball Western Australia, Perth, Australia
  3. Applied Sports, Technology, Exercise and Medicine Research Centre, Swansea University, Swansea, United Kingdom
  4. Department of Kinesiology, Center for Sport Performance, California State University, Fullerton, Fullerton, California
    Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal’s Web site (http://journals.lww.com/nsca-scj).

Abstract

The ability to change direction (COD) is an essential athletic quality in many sports, leading to crucial results such as scoring, creating breaks, or shifting momentum. Despite the extensive investigation into COD and agility in athletes through various studies, the validity of current performance measures for these abilities remains underexplored. This article critically evaluates existing measures of COD and agility and presents recommendations for enhancing their validity to foster a deeper understanding of this critical athletic quality. A video abstract describing this article is available in supplemental digital content.

Introduction

In a variety of sports, rapid changes in speed or direction can significantly impact the game's outcome. Consequently, COD ability has been investigated across different athlete populations through both cross-sectional and intervention studies. Historically, much of the research on changing direction or "cutting" mainly focused on injury risks, examining ground reaction forces, joint kinetics, and kinematics during the "plant phase" of COD. Conversely, sports performance studies typically examined COD ability by measuring total completion time of various tests designed for either planned or reactive situations. Recent trends, however, have shifted towards isolated measures of COD, focusing on entry and exit velocities or the center of mass (COM) motion throughout the test. While total time has traditionally been deemed a valid measure of COD performance, emerging research suggests it may conceal an athlete's actual COD ability, primarily due to its dependence on linear sprint capabilities. Misjudging COD or agility ability can lead to ineffective training programs focusing on incorrect performance indicators.

Purpose of the Article

This article aims to summarize and critically evaluate various types of COD and agility tests currently utilized in practical and research settings. It addresses key questions concerning COD and agility performance and offers recommendations for improvements in measurement practices targeted at both research and coaching communities.

Definitions and Delimitations

For clarity, the following definitions are critical to the discussion:

  • Change of Direction (COD): Refers specifically to the skills and abilities needed to change movement direction, velocity, or modes.
  • Agility: Originally defined as a rapid whole-body movement with a change in velocity or direction in response to a stimulus; for the purposes of this article, it will be defined similarly, as the skills and abilities to change direction, velocity, or mode in reaction to a stimulus.
  • Validity: The degree to which a test measures what it is supposed to measure.
  • Reliability: The repeatability of a measure.
  • Construct Validity: The ability of a test to represent the underlying construct adequately.
  • Discriminant Validity: The ability of a test to distinguish between different constructs.

Current Measures of Change of Direction Performance

Current assessments of COD performance vary in their methodologies, but a detailed overview can be found in Table 1, which outlines multiple tests used across diverse populations. These tests vary in distance, number of direction changes, angle of direction changes, and movement patterns, making comparisons across tests challenging due to their distinct physical demands.

A key insight is that some tests, such as the pro-agility shuttle, involve substantial periods of linear sprinting, overshadowing actual COD ability, as performance can heavily depend on linear speed rather than COD skills. It is crucial to identify whether performance improvements stem from increased COD ability or enhanced anaerobic capacity.

Influence of Linear Sprint Speed

One major limitation of many COD tests is their reliance on linear sprinting, which significantly influences total assessment time. For instance, the pro-agility shuttle involves 18.28 meters of sprinting with only two direction changes, meaning that the majority of the performance time is spent in linear movement. Even tests like the 505, designed to isolate a single direction change, require substantial linear sprinting segments, complicating the ability to accurately measure COD skills. The time taken is thus potentially confounded by an athlete's linear speed, as efficient athletes may rely on their sprinting advantages rather than true COD capabilities. Research indicates that training for linear sprinting does not necessarily equate to improved COD abilities, necessitating a focus on performance specific to the COD aspects.

Angle and Entry Velocity Influences

The performance of COD is also influenced by the angle of direction changes and the entry velocity into the COD maneuver. Factors like technique (kinematics) and loading (kinetics) during a COD can vary substantially based on the approach angle or velocity. For example, performance differences observed between traditional and modified 505 tests can be attributed to the entry speed (10-m run-up versus no run-up), where the variance in performance levels was significant, explaining only 53% of the outcomes through the traditional method. This highlights the need for accurately assessing and monitoring entry velocities during assessments as they dramatically affect overall performance outcomes.

Body Mass Considerations in Contact Sports

Research indicates that while sprint speed alone may not differentiate performers in contact sports like rugby, sprint momentum (body mass multiplied by sprint speed) could provide significant differentiation between elite and sub-elite athletes. Therefore, incorporating a mass component in assessing COD abilities for athletes involved in contact sports might yield useful insights regarding performance, such as the ability to successfully navigate tackles. Further evaluation is necessary to understand the relevance of momentum in COD assessments.

Quality versus Quantity in COD Performance

Current discourse primarily focuses on quantitative measures of COD performance. However, it is essential to complement quantitative assessments with qualitative evaluations of the technique exhibited during the COD. Techniques may include observations of trunk positioning, hip orientation relative to intended travel direction, and foot-strike patterns, among others. Additionally, checking for reliance on specific limbs during directional changes can uncover technical flaws not reflected in standard time-based measures. The height of COM and knee flexion during deceleration are also critical factors for assessment.

Recent Changes in Assessment Approaches

Emerging research has begun emphasizing the evaluation of entry and exit velocities during COD tasks to separate the multifaceted components affecting overall performance. Recent studies indicate that measuring the minimum speed attained during the COD is a powerful predictor of overall performance across different tests, emphasizing the relevance of peak acceleration and speed throughout the tests. This more nuanced approach provides deeper insights than just total time metrics.

Summary of COD Tests

A summary of typical tests shows that the complexity surrounding COD measurement lies in identifying the performance characteristics demanded by specific trials, as shown in Table 1, detailing a variety of tests and their respective characteristics, such as number of direction changes, approximate time to completion, and angles of direction changes.

Recommendations for Improvement in COD and Agility Testing

To enhance the validity of COD and agility assessments while considering equipment cost and practical implementation, the following recommendations are proposed:

  1. Understand the specific aims of testing in regard to the physical demands of the required directional changes.
  2. Evaluate performance over shorter distances and potentially increase the velocity during tests to challenge the athlete's true COD capabilities more effectively.
  3. Incorporate the COD deficit metric, which contrasts linear sprint time with COD performance, offering a clearer insight into an athlete's COD ability.
  4. When feasible, combine qualitative assessments of technical execution alongside quantitative measures to capture movement quality effectively.
  5. Favor ecologically valid stimuli (like human stimuli rather than light signals) for agility testing to enhance relevance to sport-specific performance contexts.

Conclusion

In conclusion, there is no singular, universally valid measure of COD or agility performance applicable across all athletes or sports. However, future research should focus on specific measures that assess the nuances of COD performance beyond the oversimplified "total time" approach. Key considerations must include the angle and entry velocity of COD movements, helping to pinpoint more relevant methods of performance evaluation. A combined assessment approach, reflecting on both outcome and process—what the performance yields and how it is realized—will ultimately furnish the most comprehensive evaluation of COD abilities in athletes.

Conflicts of Interest and Source of Funding

The authors report no conflicts of interest and have not disclosed any sources of funding.

Acknowledgements

The authors acknowledge Owen Walker and Damian Farrow for their critical review of this manuscript and express special thanks to Jessica Kennedy for her inspiring athletic achievement following the AFL Women’s draft.

Authors' Credentials

  • Sophia Nimphius: Associate Professor at Edith Cowan University, High Performance Manager at Softball WA
  • Samuel J. Callaghan: PhD Candidate at Edith Cowan University, collaborator with the West Australian Cricket Association
  • Neil E. Bezodis: Senior Lecturer in Biomechanics and Technology at Swansea University
  • Robert G. Lockie: Assistant Professor in the Department of Kinesiology at Cal State Fullerton