CALIFORNIA STATE UNIVERSITY, NORTHRIDGE COMPARISON OF GONIOMETRY AND INCLINOMETRY DURING PASSIVE KNEE EXTENSION: A RELIABILITY STUDY

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1 CALIFORNIA STATE UNIVERSITY, NORTHRIDGE COMPARISON OF GONIOMETRY AND INCLINOMETRY DURING PASSIVE KNEE EXTENSION: A RELIABILITY STUDY A thesis submitted in partial fulfillment of the requirements For the degree of Masters of Science in Kinesiology By Tracy Castrejana December 2016

2 Thesis of Tracy Castrejana is approved: Dr. Sean P. Flanagan Date Dr. Victoria Jaque Date Dr. Shane Stecyk, Chair Date California State University, Northridge # ii

3 Table of Contents Signature Page List of Tables List of Figures Abstract ii v vi vii Chapter 1: Introduction 1 Chapter 2: Literature Review 4 Goniometers v Inclinometers 6 Reliability 9 Standard Error of Measurement 10 Intra rater v Inter-rater Reliability 11 Goniometer 11 Inclinometer 14 Goniometer v Inclinometer Reliability 17 Measurement of Hamstring Flexibility 20 Conclusion 29 Chapter 3: Methods 32 Participants 32 Instrumentation 32 Procedure 33 Statistical Analysis 36 Chapter 4: Results 38 # iii

4 Chapter 5: Discussion 43 Limitations 55 Suggestions for Further Research 56 Clinical Implications 56 Conclusion 58 References 59 Appendix A 63 Appendix B 64 Appendix C 65 Appendix D 66 Appendix E 67 # iv

5 Lists of Tables Table 2.1. Intra rater v Inter rater Reliability: Goniometer 16 Table 2.2. Intra rater v Inter rater Reliability: Inclinometer 17 Table 2.3. Summary of 90/90 Hamstring Test Literature Review 24 Table 2.4. Description of 4 Hamstring Muscle Length Tests 28 Table 2.5 Aspects of 90/90 Hamstring Test Literature Review 30 Table 3.1. Independent and Dependent Variables for Statistical Tests 37 Table 4.1. Raw Data for Tester 1 39 Table 4.2. Raw Data for Tester 2 40 Table 4.3. Descriptive Statistics 41 Table 4.4. Inter - rater Reliability: Goniometer & Inclinometer 41 Table 4.5. Intra rater Reliability: Goniometer Tester 1 & 2 41 Table 4.6. Intra rater Reliability: Inclinometer Tester 1 & 2 42 Table 4.7. Mean Differences Between Instruments 42 Table 5.1. Mean and Standard Deviations of Our Data and Normative Data 46 Table 5.2. Methodology of Studies with Similar Data 52 Table 6.1. Pilot Data Raw Data for Tester 1 63 Table 6.2. Pilot Data Raw Data for Tester 2 64 Table 6.3. Pilot Data Descriptive Statistics 65 Table 6.4. Pilot Data Intra-rater ICC and SEM 66 Table 6.5. Pilot Data Inter-rater ICC and SEM 67 # v

6 List of Figures Figure 3.1. The Table Set up 33 Figure 3.2. Flowchart of Procedures 36 Figure 3.3. Standard Error of Measurement Equation 37 # vi

7 Abstract COMPARISON OF GONIOMETRY AND INCLINOMETRY DURING PASSIVE KNEE EXTENSION: A RELIABILITY STUDY By Tracy Castrejana Master of Science in Kinesiology Introduction: Goniometer and digital inclinometer are two devices used to measure range of motion and are used to make clinical decisions. However, it is necessary that they supply reliable measurements. The passive and active 90/90 Hamstring Test is commonly used in the clinic to determine effectiveness of interventions and hamstring muscle flexibility. Reliability of goniometry and inclinometry may vary by test performed; therefore, determining reliability of both instruments on the 90/90 Hamstring Test is warranted. Objectives: The purpose of this study is to determine the inter rater and intra rater reliability and precision of the goniometer and digital inclinometer during the 90/90 Hamstring Test. Methods: Two testers measured passive knee extension of 16 subjects with a goniometer and digital inclinometer during the 90/90 Hamstring Test. The intra rater and inter rater were calculated. Results: Inter rater reliability for the goniometer and inclinometer was very high (ICC > 0.90) with high precision (SEM < 5 ). Intra rater reliability for both instruments and testers was very high (ICC > 0.90) with high precision (SEM < 5 ). For tester 2, the mean difference between the two instruments for both days is statistically significant (p.05); however, for tester 1 on both days, it is not Conclusion: Both the goniometer and digital inclinometer have very high reliability and precision during the passive 90/90 Hamstring Test. The results of this study demonstrate that trained clinicians could use either the goniometer or inclinometer to measure knee angles during the 90/90 Hamstring Test. # vii#

8 Chapter 1: Introduction Range of motion (ROM) measurements are an important aspect of clinical practice and research. In the clinical setting ROM measurements are used to make clinical decisions for treatment and rehabilitation progressions. For example during the second stage (6-8 weeks) of post operative (post op) surgical repair of the rotator cuff patients can only be allowed to swim back stroke once passive shoulder flexion reaches 130 (Conti, 2009). Likewise, ROM measurements are frequently used in research to help determine if a specific intervention significantly improved joint motion, such as in the Nelson (2004) study. They investigated the effect eccentric training and static stretching had on hamstring flexibility by comparing hamstring ROM measurements before and after the intervention (Nelson, 2004). There are many instruments used to measure joint range of motion, but the two most commonly used are the goniometer and inclinometer. Both require similar training but have their own advantages and disadvantages. The goniometer requires that the proximal and distal arms are aligned to bony landmarks on the body in order to measure the angle created between them. Inclinometers, digital and bubble, contain sensors or fluid that are sensitive to gravity, which measures surface inclination established by either a vertical or horizontal axis (Santos, 2012). Because ROM measurements are an important aspect of clinical practice and research, it is equally important that the tools used to take these measurements are effective and reliable. A measurement is deemed reliable if the successive measurements of the same joint angle or ROM on the same participants under the same conditions give the same results (Norkin, 2009). There are two types of reliability that are evaluated in order to 1

9 determine if an instrument is reliable. Comparing if different testers can obtain the same results on the same subjects under the same conditions is inter-rater reliability, while intra-rater reliability is comparing if the same tester can obtain the same results on the same subjects during successive trails (Thomas, 2011). A number of studies have investigated the intra-rater and inter-rater reliability for both the goniometer and the digital inclinometer for various joint motions. Clapis (2008) found high and very high reliability for inter-rater measurements with the inclinometer and goniometer during hip extension. Kolber (2011) reported high to very high digital inclinometer intra-rater reliability and moderate to very high inter - rater reliability for shoulder motions (flexion, abduction, internal rotation [IR], external rotation [ER]). Santos (2012) reported the goniometer knee flexion, inclinometer elbow flexion, and inclinometer knee flexion have high to very high inter-rater reliability. These researchers also reported that their second evaluator had high to very high intra-rater reliability for only goniometer knee flexion, inclinometer knee flexion, and inclinometer knee extension; whereas, their first evaluator had high to very high intra-rater reliability for all inclinometer measurements and for goniometer knee flexion (Santos, 2012). As a whole, then, reliability for these two instruments seems to be good to excellent. But, there is some variability between studies. These differences may be attributed to body region, joint, experience of clinician, positioning, and/or the specific test being performed. Goniometers and inclinometers are used to measure joint angles during various flexibility tests. The joint angles, measured in degrees, provide objective measures to determine a baseline and also to track progress. One of the flexibility tests that indirectly measures hamstring length is the 90/90 Hamstring Test (Gajdosik, 1993). Over time, this 2

10 test has also become known as the popliteal angle, active/passive knee extension test and the knee extension angle test. When Nelson (2004) wanted to know if eccentric training and static stretching improved hamstring flexibility in high school males, the researchers used the 90/90 Hamstring Test to measure hamstring flexibility both before and after their interventions. Also, Sarikaya (2015) recently used it in a study involving patients with cerebral palsy to determine the efficacy of semtendinosus and gastrocnemius tenotomy treatments on knee extension. Since the reliability of the instrument can vary by body region, joint, positioning, and test being performed it is important to determine the reliability of both instruments specifically on the 90/90 Hamstring Test. There are studies that have evaluated the intrarater and inter-rater reliability of this test; however, none examined every aspect (reliability and precision of both instruments). To this end, the purpose of this study was to determine the inter-rater and intra-rater reliability and precision of the goniometer and the digital inclinometer during the 90/90 Hamstring Test. This study was completed based on the following assumptions. First, it was assumed that both raters were proficient with taking knee angle measurements with the goniometer and inclinometer. Both raters were graduate students in the Department of Kinesiology, certified athletic trainers with 2 years of clinical experience, practiced taking measurements together, and had completed a pilot study (See Appendices A-E). Second, it was also assumed that the participants could properly determine the same tension in order to say stop during the stretching motion. Participants were instructed to let the raters know when a strong, tolerable stretch was felt in the hamstring muscles. Knee extension was defined as the angle between the tibia and the horizontal plane. 3

11 Chapter 2: Literature Review Goniometry is the measurement of the angles created at human joints by the bony structures of the body. There are various tools used to measure these angles so that data can be gathered regarding range of motion (ROM) of the joints (Goodwin, 1992). The two measuring tools that have been widely researched are the goniometer and the inclinometer. Physiologists Camus and Amar first designed a protractor goniometer in order to measure progress in rehabilitation (Smith, 1982). By aligning proximal and distal arms to bony landmarks on the body, the goniometer measures the angle created at the joint. Another device that measures joint angles, the inclinometer, differs from the goniometer in that it uses either sensors or fluid that is sensitive to gravity within the inclinometer to measure surface inclination established by either a vertical or horizontal axis (Santos, 2012). These instruments continue to be used to measure joint ROM, and they often are utilized in both research and in making clinical decisions regarding the effectiveness of treatment interventions and rehabilitation progressions. For example, Nelson (2004) measured ROM in order to investigate if eccentric training and static stretching improved hamstring flexibility in high school males. Hamstring ROM measurements were taken before and after the intervention to determine if the treatment was effective and showed a difference between the control group and the experimental group (Nelson, 2004). Similarly, ROM measurements are commonly used after surgical procedures to determine where patients are in their rehabilitation and if they are ready to progress to the next level. For instance, post-op anterior cruciate ligament reconstruction studies suggest that a patient needs to obtain 90 of knee flexion by the end of week 1, 120 by the end of 4

12 week four, and 130 by the end of week five (Grinsven, 2010; Manske, 2012). These values are used to determine if the patient is ready to progress to the next phase of rehabilitation. Consequently, the efficacy and reliability of the tools that measure joint angles are crucial to both research and clinical applications. In addition to determining ROM of a joint, goniometric measures are a necessary component of muscle shortening tests, which are used as a part of research. Davis (2008) examined 4 commonly used tests (90/90 Hamstring Test, sacral angle, straight leg raise, and sit-and-reach) to measure hamstring muscle length. Analysis also showed poor to fair correlation among all pairs of the 4 tests. The authors of this study suggest that the 90/90 Hamstring Test should be adopted as the gold standard for hamstring length measure. They believe that compared to the other tests there is less concern for confounding factors such as pelvic position, contralateral knee placement, ankle placement, and trunk or extremity length during the 90/90 Hamstring Test. The sacral angle (SA) test was unable to classify any of the subjects as tight according to the Kendall (1993) guidelines, while the three other tests did identify the subjects as tight. The straight leg raise (SLR) test has been shown to have a mean pelvic rotation of 32.1 ; furthermore, for every 1.7 of hip motion, there was 1 of pelvic motion (Bohannon, 1985). This is important because change in pelvic position changes hamstring length as the hamstring attaches on the pelvis. Cameron (1994) found that when the contralateral knee was placed in 90 of flexion there was a significant increase in the SLR test than when the contralateral limb was maintained on the table. Liemohn (1997) noted that ankle dorsiflexion significantly limited the ROM during the sit and reach (SR) test to the point of 3cm improvement when the ankle was plantarflexed. 5

13 Kendall (1993) also suggested that trunk and extremity length variability could potentially affect the SR test. Lastly, Simoneau (1998) believes that the SR test measures the accessory motions of multiple body segments compared to the 90/90 Hamstring Test and the SLR test. Many authors have identified numerous limitations of the SR test. If the 90/90 Hamstring Test is the gold standard used for hamstring length measurement then it is warranted to examine inter- and intra-rater reliability of this test specifically. Goniometers v Inclinometers There are three general application principles of goniometry (patient positioning, stabilization, and alignment) used to standardize the measurement process in order to facilitate valid and reliable measures. Patient positioning is necessary for goniometry because proper patient positioning helps to stabilize the proximal joint segment and places the joints in a neutral starting position (Norkin, 2009). The examiner must be able to stabilize the proximal joint segment while the distal joint segment moves or else the true motion of that joint is not being measured during muscle lengthening tests (Norkin, 2009). Furthermore, the arms of the goniometer need to be aligned with the proximal and distal segments of the joint and the fulcrum needs to be aligned with the axis of rotation in order to ensure accurate and reliable measurements (Norkin, 2009). It can, at times, be challenging for one clinician to stabilize and maintain correct alignment while taking goniometric measurements. Proper positioning assists with stabilization and, therefore, should improve reliability. Many clinicians use the goniometer because it is relatively easy to use, it is inexpensive, it is portable, and it was the first device invented (Roach, 2013). However, there are several factors that can impede the ease of taking measurements with a 6

14 goniometer. First, it requires two hands to align and to maintain alignment during the measurement. This makes stabilization difficult if there is only one examiner who has to be concerned with alignment, stabilization, movement of the limb, and reading the measurement (Gajdosik, 1987). Second, the inability to properly stabilize individuals with a larger mass can also limit accurate values when measuring ROM (Gajdosik, 1987). Obesity and/or large muscle mass as well as less prominent bony structures can make palpation difficult and, therefore, alignment of the goniometer problematic (Gadjosik, 1987). Studies have shown how to increase goniometer accuracy. Inter-rater reliability can improve when examiners use consistent protocols (Grohmann, 1983; Rothstein, 1983; Watkins, 1991). Robson (1966) used a mathematical model to show that goniometers with longer arms are more accurate than goniometers with shorter arms because the longer arms help reduce errors in alignment. In addition, using the average of multiple measurements can slightly increase the reliability of one measurement (Rothstein, 1983). In addition, Norkin (2009) recommends that the following steps be taken to improve goniometric measurement technique: 1) examiners should use welldefined testing positions and anatomical landmarks in order to properly align the goniometer, 2) examiners should be careful to apply the same amount of manual force on the body part during successive measurements for passive ROM measurements, 3) examiners should instruct subjects to give the same effort in performing all motions for active ROM measurements, 4) examiners should take repeated measurements with the same measurement device to decrease the likelihood of measurement variability, and 5) 7

15 examiners should repeat their own measurements since measurements are more reliable when taken by the same examiner instead of by different examiners. Digital inclinometers and traditional goniometers require similar training (Kolber, 2011); however, the digital inclinometer (DI) has become increasingly popular with clinicians. This is due to the challenges, previously mentioned, that are associated with taking measurements with the goniometer. Digital inclinometers are portable and lightweight and they do not require alignment during the measurement process. They can be held with one hand, thereby leaving the other hand available for stabilization or movement of the extremity for passive measurements (Kolber, 2011). All these factors increase the ease with which clinicians can take ROM measurements (Kolber, 2011). Yet, there are a few limitations involved with the use of inclinometers. The primary limitation with taking accurate inclinometer measurements is that the examiner must correctly establish the zero point using a known vertical or horizontal surface (depending from which direction you are measuring) or else there will be measurement error (Kolber, 2011). In addition, the inclinometer is much more expensive than the goniometer (Kolber, 2011; Roach, 2013). Large plastic goniometers range from $12-$30. Bubble inclinometers cost at least twice as much, as they range in price from approximately $60-$90 and digital inclinometers cost approximately $1000. Both instruments have specific requirements that will improve measurement reliability. Identification of boney landmarks and an accurate zero reference point is required for the goniometer and inclinometer, respectfully. For the purposes of this study, when one examiner had a difficult time palpating a bony landmark for goniometer alignment, the second examiner confirmed the landmark was properly marked. In order to 8

16 maintain proper alignment of the goniometer, the necessary anatomical landmarks were marked on the subject. The inclinometer was zeroed at 90 horizontal, which was confirmed by the goniometer. The examiner with the inclinometer also passively extended the knee because they only needed one hand to hold the inclinometer while the examiner with the goniometer used both hands to maintain alignment. Reliability Reliability pertains to the consistency between successive measurements of the same variable in the same subject under the same conditions (Norkin, 2009; Santos, 2012). It is defined as the consistency or repeatability of a measure. Reliability also is an important part of validity because a test cannot be deemed valid if it is not reliable (Thomas, 2001). If a test is not consistent, a researcher cannot expect successive trials to give the same results and, in consequence, the test is not trustworthy (Thomas, 2001). Two commonly used forms of reliability are inter-rater reliability and intra-rater reliability. Inter-rater reliability is the degree to which different testers can obtain the same results on the same subjects under the same conditions (Thomas, 2001). It is important that procedures have acceptable levels of inter-rater reliability because if two clinicians can produce the same results when collecting data, they can be more confident in their results (Clapis, 2008). Conversely, intra-rater reliability is the degree to which the same tester can obtain similar results on the same subjects during successive trials determining that the examiner, themselves, has high reliability for the procedure. In addition, there also are three coefficients of reliability: stability, alternate forms method and internal consistency. Stability can be determined by using the test/re-test method on different days (Thomas, 2001). The alternate forms method is a way of 9

17 establishing reliability by constructing two tests that both test the same material. The tests are conducted at different times on the same individual, and then correlated to find the reliability coefficient (Thomas, 2001). Internal consistency is a way to estimate reliability that represents the consistency of scores within a test that can be conducted in various ways (same-day test-retest, split half method, Kuder-Richardson method, and coefficient of alpha technique) (Thomas, 2001). Furthermore, according to Dumholt (1993) (as cited by Johnson, 1997), the following intraclass correlation coefficient (ICC) values are recommended for categorizing reliability: 1) small reliability is below 0.25, 2) low reliability is from , 3) moderate reliability is from , 4) high reliability is from , and 5) very high reliability is above Reliable measurement techniques and instruments are required in order for clinicians to be able to provide the highest level of patient care. Measurements taken must reflect true changes within the subject instead of measurement error (Clapis, 2008). If clinicians use instruments that have poor reliability, they cannot be confident in the meaning of the measurements and, therefore, cannot make appropriate clinical decisions (Clapis, 2008). Standard Error of Measurement To this end, an important aspect of reliability is the standard error of measurement (SEM). This quantifies the precision of scores and provides an absolute index of reliability (Weir, 2005). SEM is essentially a standard deviation forming a range around a given score (Denegar, 1993). It is important to report both the ICC and the SEM because a low ICC with a small SEM can mean that the inconsistency of the measurements falls within a small range that is considered acceptable. Likewise, a high ICC may not be 10

18 acceptable if the SEM is too large for the purpose of the measurement (Denegar, 1993). For instance in ROM measurements, if the ICC is high and the SEM is 2 degrees then you can be moderately confident that a measurement change greater than 2 degrees, such as 6 degrees, is due to actual change and not measurement error. However, if with the same ICC the SEM is 7 degrees, then you would be concerned about measurement error instead of real change in the measurement (Denegar, 1993). In general, it is the responsibility of each clinician to determine acceptable limits of reliability and precision (Denegar, 1993). Although Santos (2012) set the acceptable SEM at 2 degrees, the 2-degree limit was arbitrarily selected because the goniometer scale is in 2-degree increments. Other authors did not identify acceptable SEM limits. In addition Mayerson (1984) and Nitchke (1999) identified clinically acceptable SEMs below 5 degrees. As a result, we decided that SEMs below 5 are acceptable. Intra-rater v Inter-rater Reliability Goniometer Table 2.1 shows a summary of the studies that have investigated intra-rater and inter rater reliability of the goniometer. Overall, in the goniometer studies that examined both intra and inter-rater reliability in various joints, intra-rater reliability (0.74 1) was consistently higher than inter-rater reliability ( ). However, both Santos (2012) and Kolber (2012) demonstrated higher inter-rater reliability (Kolber 0.92; Santos ) than intra-rater reliability (Kolber 0.87; Santos ) with the goniometer. Phillips (2012), Watkins (1991), White (2009), Venturini (2009), Rothstein (1983) all had very high intra-rater reliability and moderate to very high inter-rater 11

19 reliability. Even though they all had varying methods and procedures because they were measuring various joints, they all included aspects that attributed to their very high reliability. Phillips (2012) procedures included extending the goniometer arms for more accurate alignment as well as using precise anatomical landmarks leading to high reliability. Watkins (1991) and Rothstein (1983) used researchers with 7 years or more of experience and blinded the researchers to their own results and the results of the other researchers. However the main reason Watkins (1991) and Rothstein s (1983) intra-rater reliability was higher than the inter-rater reliability was because each therapist made the measurement by using his or her own technique. Meaning, from therapist to therapist, the same technique was not used consistently for any of the measurements. Increasing the consistency of techniques increases the consistency of the measurements. White (2009) created a stabilization board that maintained the hip at 90 of flexion and ensured the hip would return to the same point of each measurement as well as used 3 examiners with 9 or more years of experience. The examiners had the same role for each measurement and were blinded to the measurements. Blinding the researchers reduces error in measurement by eliminating examiner bias. Nitschke (1999), Carter (2006), Pandya (1985), Youdas (1991), and Choi (2015) all had high to very high intra-rater reliability and low to very high inter-rater reliability. These studies all had aspects in methodology that either improved the intra-rater reliability or worsened the inter-rater reliability. Nitschke (1999) did not elaborate in the methods as to the alignment of the instruments; therefore, it is difficult to determine how their methods influenced their results. Carter (2006) measured elbow range of motion on cadavers, which allowed them to stabilize the forearm using pins through the bone. 12

20 Pinning the bone fixes the arm in a stable position making it easier to measure with the goniometer because the researcher does not have to be concerned with stabilization or movement of the limb. This contributes to their intra-rater reliability and it was the only study to have an ICC of Pandya (1991) standardized their procedures, position, and order of measurements but read the goniometer to the nearest 5 which probably contributed to their low inter-rater reliability due measurement error of researchers reading the goniometer to different degrees. Youdas (1991) blinded researchers to the measurements; however, the subjects performed 30 cervical motions in one sitting (2 sets each for both researchers). The measurements at the end of the testing were most likely greater than the measurements in the beginning. This could explain their lower inter-rater reliability since the end range of motion was not consistent throughout testing and from tester to tester. Choi (2015) used novice examiners (fourth year students in the department of physical therapy) that could explain the lower inter-rater reliability as well as only high intra-rater reliability. Kolber (2012) had higher inter-rater reliability than intra-rater reliability for the goniometer. This could be attributed to their methods. They described placing the fulcrum of the goniometer over the central aspect of the glenohumeral joint which, without any more details, can be fairly subjective to the novice examiners (3 rd years students in the doctoral physical therapy program) meaning the examiners may not have consistently placed the fulcrum in the same location changing the alignment of the goniometer from measurement to measurement. The majority of Santos (2012) interrater reliability was greater than the intra-rater reliability. Measurement procedures were drawn by evaluators in order to randomize the order and there was a 5 minute wait 13

21 between the measurements of both evaluators. All of this could have contributed to the greater inter-rater reliability. Inclinometer Table 2.2 shows a summary of studies that investigated intra-rater and inter-rater reliability of the digital inclinometer (DI). There is less available evidence on inclinometer studies that examined both intra and inter-rater reliability in various joints as the inclinometer is a relatively new device compared to the goniometer. Choi (2015) Krause (2013), Phillips (2012), Santos (2012), and Venturini (2009), all demonstrated higher intra-rater reliability ( ) than inter-rater reliability ( ) with the inclinometer. Refer to Table 2.2 to view the differences between intra-rater and inter-rater values for each individual study. Venturini (2009) had very high intra-rater reliability and high inter-rater reliability with the inclinometer. Santos (2012), Krause (2013), and Choi (2015) all had high to very high intra-rater reliability and small to very high inter-rater reliability. O Connor (2015) had higher right (R) and left (L) inter-rater reliability (R 0.98; L 0.99) than intra-rater reliability (R ; L ) using a bubble inclinometer. Patients held their thighs at 90 degrees with no objective feedback (inclinometer or goniometer confirmation) or stabilization to hold them at 90 degrees. This means there may have been some variability as to the testing position because there is no guarantee that the subject maintained the 90 degree hip angle consistently throughout testing. If testing position is not standardized it reduces reliability. Kolber (2012) also demonstrated higher inter-rater reliability (DI 0.89) than intra-rater (DI 0.88), however, a difference of 0.01 is not considerably great and because both values fall into 14

22 the high reliability group these values are considered equal. Neither Kolber (2011) nor Krause (2015) consistently had higher intra or inter-rater reliability over the other. Kolber (2011) had higher intra-rater reliability for shoulder flexion (intra rater 0.83, inter-rater 0.58) and external rotation (intra-rater 0.94, inter-rater 0.88) but higher inter-rater reliability internal rotation (inter-rater 0.93, intra-rater 0.87). Krause (2015) had higher inter-rater reliability for passive hip internal rotation (inter-rater 0.93, intra rater 0.84) but higher intra-rater reliability for active unilateral hip internal rotation (intra-rater 0.92, inter-rater 0.89). 15

23 Table 2.1 Intra-rater v Inter-rater Reliability: Goniometer Study Joint motion Intra rater Inter - Rater Phillips (2012) Knee Extension/ Flexion 0.98/ / 0.85 Watkins (1991) Knee Extension/ Flexion 0.98/ / 0.90 White (2009) Knee Extension Venturini (2009) Active Ankle Dorsiflexion Rothstein (1983) Elbow Extension Elbow Flexion Knee Extension Knee Flexion Nitschke (1999) Thoracolumbar Flexion Thoracolumbar Extension Carter (2006) Wrist Measurements Ulnar Wrist Measurements Radial Wrist Measurements Dorsal Volar , Pandya (1985) Shoulder Abduction Elbow Extension Wrist Extension Hip Extension Knee Extension Ankle Dorsi Flexion Iiliotibial Band Youdas (1991) Cervical Flexion/ Extension 0.83/ / 0.79 Choi (2015) Craig s Test Femoral Anteversion 0.82, Kolber (2012) Scapular Plane Shoulder Elevation Santos (2012) Elbow Flexion Elbow Extension Knee Flexion Knee Extension 0.06, , , ,

24 Table 2.2 Intra-rater v Inter-rater Reliability: Inclinometer Study Joint motion Intra rater Inter - Rater Venturini (2009) Active Ankle Dorsiflexion 0.91, Santos (2012) Elbow Flexion Elbow Extension Knee Flexion Knee Extension 0.87, , , , Krause (2013) Dial Test External Rotation Tibia Choi (2015) Craig s Test Femoral Anteversion 0.73, Kolber (2011) Shoulder Flexion Shoulder Abduction Shoulder Internal Rotation Shoulder External Rotation Krause (2015) Hip Passive Internal Rotation Hip Active Internal Rotation (Unilateral) Hip Active Internal Rotation (Bilateral) Kolber (2012) Scapular Plane Shoulder Elevation O Conner (2015) Knee Extension R L R 0.98 L 0.99 Goniometer v Inclinometer Reliability In the research comparing inclinometers and goniometers, there is some speculation regarding whether or not the inclinometer is as reliable as the goniometer. Clapis (2008) investigated the reliability of both a gravity inclinometer and a goniometer on hip extension during the modified Thomas Test. They found high reliability (ICC 0.89, SEM 2.1 ) for the inclinometer and very high reliability (ICC 0.91, SEM 1.9 ) for the goniometer. They used two physical therapists examiners that had at least 16 years of 17

25 clinical experience. This means that clinicians with similar experience levels could produce reliable measurements with a goniometer or an inclinometer for the modified Thomas Test (Clapis, 2008). Kolber (2012) noted that the intra-rater reliability for the goniometer during active shoulder ROM for flexion, abduction, ER, and IR was very high (ICCs 0.95, 0.97, 0.94, 0.95; SEMs 2-3 ). They also found intra-rater reliability for the digital inclinometer for flexion, abduction, ER, and IR was also very high (ICCs 0.95, 0.97, 0.98, 0.97; SEMs 2 ). It is interesting to note that flexion and abduction ICCs were the same for both instruments while rotation values had higher ICCs with the inclinometer. This could be due to the more complex nature of the rotational movements, making it more difficult to maintain stabilization and alignment with the goniometer compared to the inclinometer. Roach (2013) investigated hip mobility with the digital inclinometer and the goniometer. These researchers found that the ICC was 0.80 for the goniometer and 0.90 for the inclinometer (no SEMs reported). But they found significant differences between measurements of the goniometer and the inclinometer for extension, internal rotation, and external rotation. The average difference between the goniometer and the digital inclinometer was 3.2 for extension, internal rotation it was 4.5, and external rotation it was 3.8 (Roach, 2013). Overall, the digital inclinometer showed increased values for hip extension and external rotation, but internal rotation had the greatest average difference between the two instruments (Roach, 2013). Unfortunately, the study did not speculate as to why this was the case but it could be due to the fact that the inclinometer is easier to stabilize while passively moving an extremity. 18

26 Santos (2012) examined intra and inter-rater reliability of the goniometer and the digital inclinometer on both knee and elbow extension and flexion. They compared measurement values of two testers from day to day and measurements values of one tester from subject to subject. Inter-rater reliability with the goniometer was small for elbow extension (ICC 0.24; SEM 0.78 ) and moderate for both knee extension (ICC 0.55; SEM 0.76 ) and elbow flexion (ICC 0.52; SEM 2.76 ). It was high for elbow flexion (ICC 0.70; SEM 3.18 ) with the inclinometer, and it was very high for knee flexion measurements for both testers (ICC 0.96, SEM 2.6 ; ICC 0.98, SEM 3.21 for goniometer and inclinometer respectively). Tester 2, however, had a SEM of for inclinometer knee flexion. Since SEM shows degree of precision, this SEM leads the readers to believe that Tester 2 is not precise in taking knee flexion measurements with the inclinometer. This SEM means that they are 95% certain that the measurement they obtain is plus/minus of the actual measurement. This degree of error is too large, especially when small changes in ROM can be clinically significant. For instance, if normal knee flexion is 130, 25.5 of error is approximately 20% of the full ROM. Measurements from this rater would not be clinically meaningful. This needs to be taken into account when assessing Tester 2 s ICC for inclinometer knee flexion. Overall, the inclinometer had higher ICC values than the goniometer in the Santos (2012) study. Thus, the researchers believe that the inclinometer was more reliable in the majority of the measurements taken. They attribute this to the ease of use of the inclinometer and the fact that no anatomic alignment is needed when it is used (Santos, 2012). This agrees with another study (Venturini, 2006) that found higher inter - rater inclinometer reliability values (ICC 0.83) over the goniometer (ICC 0.72) when looking 19

27 at ankle dorsiflexion ROM. However, the intra-rater reliability values were the same for both instruments (ICC 0.91, 0.97) (Venturini, 2006). Looking at Tables 2.1 and 2.2, neither active nor passive motions were more reliable regardless of instruments used. Even the studies that have examined active and passive reliability together do not consistently show that reliability of active or passive motion is more reliable with one instrument or another. Reurink (2013) measured active and passive knee extension with a digital inclinometer and found that active inter-rater reliability to be 0.76 with SEMs of 6.5 degrees and passive inter-rater reliability to be 0.69 with SEMs of 7.5 degrees. Krause (2015) examined active and passive internal rotation with a digital inclinometer and found mixed reviews. Passive hip internal rotation intra-rater reliability was 0.84 and inter-rater reliability was 0.93 while active intra-rater reliability was 0.92 and inter-rater reliability was Gajodsik (1993) examined active and passive knee extension with the goniometer and found passive intrarater reliability to be 0.90 and active intra-rater reliability to be Measuring Hamstring Flexibility Clinically, hamstring muscle flexibility is measured indirectly by determining the angle measurement of unilateral knee extension with the hip flexed to 90 (Herrington, 2013). This is commonly referred to as popliteal angle, (active/passive) knee extension test, and knee flexion angle. In order to avoid confusion these tests will be referred to the 90/90 Hamstring Test throughout the document. Davis (2008), after comparing the validity of 4 common tests used to measure hamstring muscle flexibility, suggests that the passive 90/90 Hamstring Test should be adopted as the gold standard for measuring hamstring flexibility. 20

28 In addition to its clinical application, this test is also used in research. For instance, Nelson (2004) investigated the effects of eccentric training and static stretching on hamstring flexibility in high school males. The 90/90 Hamstring Test was used to assess hamstring flexibility; the measurement protocol required the patients lay supine with the hip and knee flexed to 90 in order to passively extend the knee and measure the knee angle. This was done both before and after the intervention. They found significant differences (P <.05) between the control group (gain = 1.67 ) and both the eccentric training (gain = ) and static stretching (gain = ) groups but no difference between the eccentric and static stretching groups. Other researchers have used the 90/90 Hamstring Test to measure hamstring flexibility. Recently, Sarikaya (2015) used it in a study involving patients with cerebral palsy to determine the efficacy of semtendinosus and gastrocnemius tenotomy treatments on knee extension. A total of 78 semitendinosus tenotomies and 28 grastrocnemius tenotomies were performed. Knee extension was measured, before and after surgery, with the patient supine and the hip and knee flexed to 90. The knee was passively extended until mild resistance was felt. They found that semitendinosus and gastrocnemius tenotomies significantly improved knee extension (30.1% and 12 % respectfully; p = ). Youdas (2005) used the 90/90 Hamstring Test for a cross-sectional descriptive study on the influence of gender and age on hamstring muscle flexibility in healthy adults. They measured hamstring muscle flexibility two ways using the passive straight leg raise and the 90/90 Hamstring Test. For the 90/90 Hamstring Test the subject was supine with the hip and knee flexed to 90 and the knee was passively extended until firm 21

29 resistance was felt. They found that hamstring muscle flexibility was significantly different between genders for both methods of measurements with women having greater flexibility. This provided typical values of hamstring flexibility in adults in multiple age groups (20 80 years of age) that are useful for comparison purposes. A descriptive study by Katz (1992) used the 90/90 Hamstring Test on 482 normal children. According to this study, children ages 1-3 had a mean knee extension angle of 6 and children ages 4-10 had a mean knee extension angle of 24. As a result, this study determined popliteal angle less than 50 does not affect normal gait therefore, a popliteal angle of greater than 50 indicated abnormal hamstring tightness in these age groups (Katz, 1992). Herrington (2013) examined the effect of pelvis position on 90/90 hamstring flexibility. Subjects were supine with the hip and knee flexed to 90 when the knee was passively extended to the point of firm resistance. They determined that there was a mean angle difference of 13.4 (P = ) for the 90/90 measurement between anterior and posterior pelvic tilt groups with posterior pelvic tilt being greater. These results demonstrated that pelvic position has a significant effect on the angles taken in the 90/90 position therefore, pelvic position should be taken into account when measuring hamstring muscle flexibility. Despite a great deal of research on both instruments and the 90/90 Hamstring Test separately, there currently are only a few studies that examine the inter-rater and intrarater reliability of the goniometer and digital inclinometer during the passive 90/90 Hamstring Test. Rothstein (1983) and Watkins (1991) demonstrated that inter-rater reliability of the goniometer was higher (ICC 0.74, 0.87 respectfully) when therapists 22

30 used the same subject positioning compared to when they used different subject positioning (ICC 0.69, 0.84 respectfully) for measuring knee extension. Because there are multiple positions in which knee extension can be tested, it is necessary to determine the intra and inter-rater reliability for both instruments on the 90/90 Hamstring Test before confidently employing these techniques in an intervention study. Table 2.3 provides a summary of reliability studies for the 90/90 Hamstring Test. The ICC ranges for interrater reliability and intra-rater reliability for the 90/90 Hamstring Test are ICC and 0.80 to ICC 0.99, respectively. 23

31 Table 2.3 Summary of 90/90 Hamstring Test Literature Review Study Instrument Inter ICC Intra ICC Gnat 2010 Goniometer SEM Passive or Active P Guex 2012 Nishikawa 2015 Kuilart 2005 Video analysis N/A 0.80 N/A P Inclinometer N/A 0.97 N/A A Goniometer N/A 0.99 N/A A Reurink 2013 Inclinometer, Active Injured, Active Non Injured, Passive Injured, Passive Non Injured P&A Muyor 2013 Inclinometer N/A P Davis 2008 Inclinometer N/A 0.94 N/A P Gnat (2010) examined the inter-rater reliability of the goniometer during the passive 90/90 Hamstring Test. The subjects were in a supine position in 90 of hip flexion and approximately (not confirmed) 90 of knee flexion. They reported high interrater reliability (ICC ; SEM ) values for the goniometer. Gnat used raters with 6-12 years of professional experience that also trained together and separately on measuring the passive 90/90 Hamstring Test for a month before the study. 24

32 They also used a force gauge in order to consecutively give the same force for each test. These two factors most likely increased their inter-rater reliability. Guex (2012) examined the passive 90/90 Hamstring Test used to measure hamstring tightness. The test was performed with the subject supine with the hip and knee flexed to 90. A force of 68.7 N was applied proximal to the lateral malleolus during passive extension of the knee and the angles were measured with video-analysis software. The results showed high intra-rater reliability (ICC = 0.80) for the passive 90/90 Hamstring Test but SEMs were not reported. Once again, the use of the force gauge probably lead to their high intra-rater reliability values. Nishikawa (2015) observed the effects of passive and active stretching on hamstring flexibility. The active 90/90 Hamstring Test was used to assess hamstring flexibility and measurements were taken with an inclinometer. Subjects were supine with the hip and knee flexed to 90. They then actively extended their knee to the point of mild resistance. This study s pilot data revealed very high intra-rater reliability (ICC 0.97) for the active 90/90 Hamstring Test with the inclinometer. Nishikawa did not report SEMs, therefore, we do not know their precision. Subject s lordosis was supported with a lumbar roll, which could have aided in the very high intra-rater reliability. Lumbar roll support helped stabilize the pelvis therefore decreasing the amount of pelvic tilt variations from test to test. Because the hamstrings attach on the pelvis (Moore, 2010) any change in pelvic position will affect the initial length of the hamstring affecting the amount of stretch the muscle can withstand. Kuilart (2005) examined perceived hamstring tightness by using the active 90/90 Hamstring Test and the Slump test. Their purpose was to establish average data on the 25

33 active 90/90 Hamstring Test in subjects with perceived hamstring tightness for comparison and to establish occurrence and location of symptoms brought on by the Slump test. Their procedures for the test had hip flexion at 90. Overall, the pilot data showed that the intra-rater reliability of the active 90/90 Hamstring Test was 0.99 for the goniometer but no SEMs were reported. Their very high reliability is due to taking a picture of the end range knee position, laying a grid over the picture, and then measuring the angle with a goniometer. Potential errors resulting from attempting to stabilize the lower extremity, maintaining alignment of the goniometer, and reading the measurement simultaneously were limited since positioning the subject and the measurements were not done simultaneously. Reurink (2013) examined the reliability of the digital inclinometer during the 90/90 Hamstring Test on subjects with acute hamstring strains. They standardized the hip in 90 flexion. They reported high inter-rater reliability for the active 90/90 Hamstring Test in both the injured leg (ICC 0.89, SEM 5.3 ) and non-injured leg (ICC 0.76, SEM 6.5 ). In addition, they reported high inter-rater reliability (ICC 0.77, SEM 7.6 ) for the passive 90/90 Hamstring Test in the injured extremity but only moderate reliability (ICC 0.69, SEM 7.5 ) for the non-injured extremity. Their testers were only given one session to practice the testing protocol, which could explain why their reliability values were moderate to high. They determined that since they found good inter-rater reliability for the active and the passive 90/90 Hamstring Test in injured hamstrings then both tests can be used reliably to assess flexibility in the hamstrings. They did not report an acceptable SEM range. According to our standards (SEMs < 5 ) all of the SEMs are large, meaning the precision was poor. In this study the active ICC values were consistently higher than 26

34 the passive ICC values. This could be because the subject could more accurately determine the stretch end range during active knee extension compared to passive extension of the knee by the examiner. Muyor (2013) examined the relationships between hamstring muscle extensibility, sagittal spinal curvatures, and pelvic tilt in cyclists. Hamstring muscle extensibility was determined by performing the passive 90/90 Hamstring Test measured with a uni-level inclinometer. Subjects were supine with the hip flexed to 90 and the foot in plantar flexion. The knee then was passively extended until moderate tolerance was felt. The pilot data revealed that intra-rater reliability for inclinometer measurement of the passive 90/90 Hamstring Test was high with ICCs 0.91 and SEMs that ranged from for both legs. The low value of the SEMs mean this study had good precision and there was a 95% chance that the values measured are within of the actual ROM values. Their very high reliability and precision could be due to standardizing the foot position in order to reduce neural tension and stabilizing the hip not being tested in extension. Davis (2008) determined the concurrent validity of 4 commonly used tests (Table 2.4) to measure hamstring muscle flexibility. For the 90/90 Hamstring Test, the subject was supine with the hip flexed to 90. The knee was passively extended until the subject reported a strong, but tolerable, stretch. The angle then was measured with an inclinometer. Pilot data showed very high intra-rater reliability ( ) for all 4 tests. Specifically, the passive 90/90 Hamstring Test had an ICC of They had a second inclinometer on the thigh so that they were aware if the thigh deviated from 90 degrees as well as strapped the contralateral leg to the table. All of this contributed to their very high 27

35 reliability because it improved stability in order to ensure that accessory movement was not allowed. Analysis also showed poor to fair correlation among all pairs of the 4 tests. The authors of this study suggest that the passive 90/90 Hamstring Test should be adopted as the gold standard for hamstring flexibility measure however, since they did not report SEMs we do not know their precision of their measurements. Table 2.4 Descriptions of 4 Hamstring Muscle Flexibility Tests (Davis, 2008) Test Description 90/90 Hamstring Test Supine with hips and knees fully extended. Passively raise lower extremity to 90 of hip flexion. Knee passively straightened until a strong but tolerable stretch is felt. Measured angle of the knee. Sacral Angle Straight Leg Raise Sit and Reach Sitting with the knees fully extended and hips in neutral rotation and fully adducted. The subject reached forward until a strong but tolerable stretch is felt. Measured angle formed between sacrum and horizontal plane. Supine with hips and knees fully extended. Passively raises the test extremity until a strong but tolerable stretch is felt. Measured the angle of the lower extremity from the horizontal. Sitting with the knees fully extended and hips in neutral rotation and fully adducted. The subject reaches forward until a strong but tolerable stretch is felt. Measured the distance the subject was able to reach forward. The reliability data available for the 90/90 Hamstring Test consistently comes from pilot studies conducted as a part of experimental research. Also, as seen in Table 2.3 most of it is regarding intra-rater reliability and the use of the digital inclinometer. Not a single study we reviewed examined both the inter- and intra-rater reliability of both instruments in the 90/90 Hamstring Test with the hip stabilized at 90 degrees and 28

36 reported SEMs along with ICCs. Therefore, determining the inter and intra-rater reliability of both instruments on the 90/90 Hamstring Test - a test that is commonly used in other studies to determine effectiveness of interventions and hamstring muscle flexibility - is warranted. Conclusion Both the goniometer and the digital inclinometer (DI) are devices that are used to measure joint angles and ROM. These measurements are used to make clinical decisions regarding the effectiveness of treatment interventions and rehabilitation progressions. Reliable and accurate measurements of tests that assess hamstring flexibility are important clinically and for research purposes. Although both devices have good inter and intra-rater reliability each device has limitations to clinical use (eg. cost, two hand versus one hand use, maintaining alignment of the goniometer, zeroing of the inclinometer, palpation for land marks for the goniometer, etc.) leading to clinicians choosing one over the other. These are all factors that will be addressed in our study, as previously mentioned, and will be elaborated on during the procedures of our methods section. Since the reliability of the goniometer and the inclinometer may vary by test performed, and the clinician or researcher taking the measurements, it is important to determine the reliability of both instruments specifically on the 90/90 Hamstring Test. Much of the reliability data available for the 90/90 Hamstring Test is from pilot studies. Most of the studies assessed intra-rater reliability of the digital inclinometer only, as seen in Table 2.5. Not a single study reviewed examined both the inter and intra-rater reliability of both instruments on the 90/90 Hamstring Test where the hip was confirmed 29

37 at 90 degrees and SEMs were reported along with ICCs. Table 2.5 Aspects of 90/90 Hamstring Test Literature Review Study Instrument Reliability 90/90 SEMs Gnat Goniometer Inter-rater Knee approx. 90 Guex Video Analysis Intra-rater Hip & Knee N/A 2012 Nishikawa Inclinometer Intra-rater Hip & Knee N/A 2015 Kuilart Goniometer Intra-rater Hip N/A 2005 Reurink Inclinometer Inter-rater Hip Muyor Inclinometer Intra-rater Hip Davis 2008 Inclinometer Intra-rater Hip N/A Note. N/A = not = at Therefore, determining the inter and intra-rater reliability of both instruments on the 90/90 Hamstring Test, a test that is commonly used in other studies to determine effectiveness of interventions and hamstring muscle flexibility, is warranted. To this end, the purpose of this study was to determine the inter-rater and intra-rater reliability and precision of the goniometer and the digital inclinometer during the 90/90 Hamstring Test as well as to compare the reliability of both devices. Our hypothesis is that the goniometer and the DI will have high to very high inter-rater and intra-rater reliability 30

38 and precision less than 5 during the 90/90 Hamstring Test and the inclinometer will have higher reliability than the goniometer during the 90/90 Hamstring Test. 31

39 Chapter 3: Methods Participants Sixteen physically active university students, years of age, were recruited for this study by word of mouth. Davis (2008), Gnat (2010), Guex (2012), Muyor (2013), and Nishikawa (2015) used subjects in their studies while Reurink (2013) used 50 subjects. Although Kuilart (2005) used 42 subjects, the purposes of his investigation were to determine knee extension angle on individuals with perceived hamstring tightness and to determine the location of pain or discomfort during the slump test, and not to, specifically test the reliability of the goniometer. Additional inclusion criteria included: 1) no hamstring pain, 2) no contraindications to hamstring stretching, and 3) no surgeries within the last 12 months that could have affected hamstring muscle flexibility. Interested individuals contacted the researcher to schedule the first data collection session. Subjects read an informed consent form and were free to ask questions to clarify any components of the research project that they did not understand. Subjects who provided written consent then completed the Physical Activity Readiness Questionnaire (PAR-Q). Those who answered No to all questions on the PAR-Q were allowed to participate in the study. University IRB approval was obtained before recruitment commenced. Instrumentation An Acumar digital inclinometer (Lafayette Instrument Company Lafayette, IN) and a Baseline full circle goniometer (Baseline, Aurora, IL, USA) were used to measure passive knee extension while performing the 90/90 Hamstring Test. A modified version of the dynamometer anchoring system developed by Nadler (2000) was used to establish 32

40 and maintain hip flexion at 90 degrees (Figure 3.1). A seat belt strap was used to stabilize the thigh to the anchoring system. Figure 3.1 The Table Setup Procedure Pilot data was collected in order to ensure that the researchers were comfortable with the setup and could properly use the instruments (Appendices A-E). The procedures used in the pilot study and the current study were the same. Once consent was obtained, subjects changed into shorts for the data collection session. In order to establish the proper alignment of the instruments, permission was obtained from the subjects to mark their bodies over 4 anatomical landmarks on their dominant leg. Leg dominance was defined as the foot that the subject would use to kick a ball. Then, the center of lateral malleolus was marked for goniometer alignment followed by the midpoint of the shin (distance between the tibial tuberosity and lateral 33