Validity and Reliability of 2D Motion Analysis to measure lower extremity kinematics in Youth and Adolescent Recreational Athletes

INTRODUCTION

Injuries are a common consequence to participation in sports. These injuries in turn result in time loss from sport, deconditioning, medical costs, and sometimes even retirement from sport. (1) Young people are more prone to injuries than adults. Studies that investigate the sports related injuries in adolescent recreational athletes revealed that adolescent athletes are prone to lower extremity injuries across all sports. (2)

One of the reasons that children and young people are at a higher risk of injury than adults could be because most activities are not tailored to their specific age group’s motor skills. Often, teenagers play by adult rules with equipment that is not modified to their sizes. Competitive basketball baskets, for example, come in only one height, and practically all sports use the same ball size, which is the one used by adults. (3)

Another contributing factor could be the growth spurt during adolescence when maturation related changes occur. These changes include rapid increase in height that is accompanied by increases in length of bone, muscle, ligament, and other structures at different rates.  When the body adjusts to these changes, compensatory strategies may be used to perform movements. (3,4)

In order to prevent injuries, it becomes necessary to study the changes in movement patterns during growth and screen for potential risk factors for injuries. These altered movement patterns could contribute to injury mechanisms. By evaluating these movements for their mechanism, it is possible to identify injury risk and modify training to meet the athlete’s requirements, educate the athlete, and minimize injuries.  Gender is another factor that affects the risk for injuries during maturation. Males and females undergo maturation at different ages and adapt their movement patterns differently. (5)

3-Dimensional (3D) motion capture systems have been established as the "gold standard" in evaluating motion and movement patterns. These systems have established validity and reliability to measure motion during multiple functional and sport – specific tasks and can accurately determine motion in all the planes available. As a result of their high cost, labour intensive method, accessibility, and use of multiple sensors that do not always relate during tasks, 3D motion capture systems have limited utility in the on-field context. (6,7**)**

2-Dimensional (2D) motion analyses are a potential solution to the current limitations of 3D motion analysis for assessments due ease of access and relatively simple processes. Multiple studies have established the validity and reliability of 2D motion analysis in some populations and settings. Fewer studies have compared it to the gold standard. Validation of 2D Motion Analysis will help understand the scope of application of 2D motion analysis. (6,7)

The purpose of the study is study is to determine the scope of application of 2D motion analysis in identifying risk of injuries as athletes undergo maturation.

NEED FOR THE STUDY

Maturation and growth significantly alter the performance of motor skills. These changes are evident when screened using 3-Dimensional Motion Analysis. However, the access to 3D motion analysis is limited and expensive. 2D motion analysis is easily accessible and cost effective. There is a need to validate the use of 2D motion analysis the youth undergoing maturation for accurate and accessible screening.

AIM OF THE STUDY

To determine the validity and reliability of 2D motion analysis in youth and adolescent female recreational athletes.

OBJECTIVES OF THE STUDY

To determine the concurrent validity of 2D Motion Analysis as compared to 3D motion analysis to measure lower extremity biomechanics of young females in the different stages of maturation.

To determine the inter-rate and intra-rater reliability of 2D motion analysis to measure lower extremity biomechanics of young females in the different stages of maturation.