Emphasis on injury prevention is increasing in sport to reduce the health and economic impact of injury and maximise performance (Bahr and Krosshaug, 2005; McBain et al., 2012 Peate et al., 2007; Turbeville et al., 2003; Tyler et al., 2006; Webborn, 2012; Zazulak et al., 2007). Injury results when body tissue is unable to cope with the applied stresses, whether acute or chronic (McBain et al., 2012). Multiple factors increase the risk of injury and invariably injuries result from a combination of factors including; history of pain, previous injury, acquired hypermobility, aerobic fitness, changes in the control of movement (Bahr and Krosshaug, 2005; McBain et al., 2012; Plisky et al., 2006, Roussel et al 2009; Webborn, 2012; Yeung et al., 2009). Various strategies have been employed to reduce both extrinsic causes of injury (e.g. unavoidable direct contact trauma and intrinsic causes of injury (e.g. non-contact injury related to overuse, or poor movement technique, efficiency or control), but consistent predictors of injury are still lacking (Butler at al., 2010; Garrick, 2004).
Although pre-season screening has been part of the routine in sport for some time, some approaches lack the complexity required to identify movement impairments relevant to everyday activities. In other testing protocols, there has been an emphasis on measuring joint mobility, muscle extensibility, endurance and strength, as well as fitness tests and physiological testing (Butler et al., 2010; Mottram and Comerford, 2008; Myer et al., 2008; Yeung et al., 2009). Such tests have a role in providing benchmarks for rescreening reference during the season and post injury, and provide some indication of limitations that need addressing but many do not predict injury (Butler et al., 2010).
Currently, the strongest predictor of injury is previous injury (Chalmers, 2002; Fulton et al., 2014; Tyler et al., 2006) but this is clearly not desirable as an ongoing predictor. It has been suggested that a change may occur following injury, which could be explained as a change in motor control (Kiesel et al., 2009; MacDonald et al., 2009). Central nervous system mediated motor control is vital to both production and control of movement (Hodges and Smeets 2015), and more recently the focus of assessing movement impairments and developing movement retraining programs has moved towards optimising the control of movement (Cook et al., 2006a; Cook et al., 2006b, Luomajoki et al., 2010, Worsley et al., 2013).
Quality of movement, specifically control of movement, is now being recognised as an important element of assessment of movement efficiency as well as range (Simmonds and Keer, 2007; Roussel et al., 2009). The identification and correction of movement control impairments have been recognised as an important part of assessing and rehabilitating injury (Comerford and Mot tram, 2001; Comerford and Mottram 2012; Luomajoki et al., 2007; Sahrmann, 2014) but attention is now focussing on protocols to evaluate uninjured groups to determine non-symptomatic deficits within the kinetic chain of functional movement patterns that might predispose to injury (Cook et al., 2006a; 2006b; Kiesel et al., 2007; Peate et al., 2007; Plisky et al., 2006; Roussel et al., 2009). This new perspective in screening has been used to develop a tool known as The Performance Matrix (TPM). This tool employs generic multiple joint tasks that are functionally relevant, but not necessarily habitual, and have been modified to test the cognitive control of movement. The protocol identifies inefficient control of movement (weak links) within the kinetic chain indicating the presence of uncontrolled movement (UCM; Comerford and Mottram, 2012). The key features of TPM that differ from other movement screens include: 1) detailing the site and direction of UCM to direct specific targeted retraining; 2) evaluation of low and high threshold UCM explained below; 3) testing for active control of movement to benchmark standards (not natural or habitual movement patterns), 4) evaluation of movement control and not pain, which, when present, does not mean a fail in this screen, as some people have good control in the presence of pain; 5) the software produces a risk algorithm that helps establish retraining priorities (although this has yet to be validated). 6) A unique classification of subgroups of movement control impairments as high risk, low risk and assets.
Uncontrolled movement is described for the purpose of this screening process as a lack of ability to cognitively co-ordinate and control motion efficiently to benchmark standards at a particular body segment (Comerford and Mottram, 2012). A loss of the ability to control movement is thought to increase the loads and stresses on the joint, increasing susceptibility to injury (Sterling et al., 2001).
Motor control is key to optimising control of movement and ensuring the coordinated interplay of the various components of the movement system: the articular, myofascial and connective tissue, and neural systems. Changes in motor control result in altered patterns of recruitment, with inhibition in some muscle groups and increased activity in others (Hodges and Richardson, 1996; O'Sullivan, 2005; Sterling et al., 2001). Altered muscle recruitment strategies and motor control impairments may result from previous injury (O'Sullivan, 2005; Sterling et al., 2001) fatigue, stiffness i.e. loss of range of joint of motion or myofascial extensibility (Cook et al., 2006a), or muscle imbalances (Cook et al., 2006a; Sahrmann, 2002). Impaired motor control can also lead to compensatory movements (Roussel et al., 2009; Zazulak et al., 2007).
The Foundation Matrix forms part of The Performance Matrix movement screening system (Movement Performance Solutions Ltd). The Performance Matrix is the generic name for the entire group of screening tests developed by Movement Performance Solutions. The Foundation Matrix, is the most commonly used screening tool in the database, and is the entry level screen, which is designed to identify performance related inefficient control of movement in the kinetic chain. This entry level matrix was therefore chosen for the present study. Other screens in the database are sport specific, e.g. football and golf, or region specific e.g. low back, or occupation specific e.g. office worker or tactical athlete, such as fire fighter or police. Using a series of multi-joint functionally relevant tests (listed in Table 2), The Foundation Matrix screen evaluates movement control efficiency. The protocol assesses both the site and direction of uncontrolled movement in different joint systems, and evaluates these control impairments under two different, but functionally relevant physiological situations, low (Figure 1 for example of test 1) and high threshold testing (Figure 2 for example of test 9). The screening tool assesses deficits in the control of non-fatiguing alignment and co-ordination skills in what is referred to as 'low threshold' tasks, and assesses deficits in movement control during fatiguing strength and speed challenges in what is referred to as 'high threshold' tasks (Mottram and Comerford 2008). The objective of The Foundation Matrix screening tool is to provide the assessor with details of the site, direction, and threshold of uncontrolled movement, to allow for the development of a specific training programme. When considering the utility of a test, both reliability (intra and inter-rater) and validity must be established.
Although some movement control tests have been evaluated for reliability and validity (Luomajoki et al., 2007; Roussel et al., 2009; Teyhen et al., 2012), the reliability of the battery of movement control tests in The Foundation Matrix has not been examined. Therefore, the aim of the present study was to establish both the intra and inter-rater reliability of experienced therapists in rating performance of nine of the 10 tests from The Foundation Matrix. These include five low threshold tests of alignment and coordination control and four high threshold tests of strength and speed control. The reason for excluding one of the high threshold tests is explained below.
Twenty university sports students (11 females; 9 males; aged = 21 [+ or -] 3) participated in the study. Participants were asymptomatic and were excluded if they had a present pathology, injury, pain, surgery, a musculoskeletal injury within the past six months, or were pregnant. Prior to screening, all participants gave written, informed consent, and the Research Ethics Committee of the University approved the study.
Two experienced musculoskeletal therapists, who were specialists in the field of movement control, assessed the efficiency of movement control during the performance of tests. Therapist 1 had 23 years' experience in musculoskeletal physiotherapy and 14 years' experience in movement control assessment and re-training, and Therapist 2 had 16 years' experience in musculoskeletal physiotherapy and 7 years' experience in movement control assessment and re-training.
Both therapists assessed participants using the battery screening protocol comprising nine movement control tests (Table 2). Each participant was scheduled to a 45 minute session. Both therapists completed the screening process at the same time independently, without conferring, during which time testing was video recorded for retrospective analysis of intra-rater reliability of assessing test performance on another occasion (Butler et al., 2012; Fersum et al., 2009; Luomajoki et al., 2007). Six digital cameras (Casio exfh20) were used to record participants performing the tests, and were set up to give anterior, posterior and lateral views. Tripods and angle adjustment allowed for variation in positioning of the tests. All participants wore black lycra shorts and females wore a sports top that allowed...