Knee Position Error Detection in Closed and Open ...

Knee Position Error Detection in Closed and Open Kinetic Chain Tasks During Concurrent Cognitive Distraction '

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Russell A. Taylor, MA Philip H. Marshall, PhD Ronald D. Dunlap, PhD Clayton D. Gable, PhD, PT4 Phillip S. Sizer, PT, ME^

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teindler (31) proposed that limbs of the body could be seen as a chain of rigid segments connected by a series of joints. Movements of limbs of the body can be classified as open kinetic chain, consisting of free movement of the terminal segment, or closed kinetic chain, consisting of a fixed terminal segment which is restricted in the number of possible movements. The movement of one joint in closed kinetic chain movement results in the movement of all other joints of the kinetic chain in a predictable manner, whereas in an open kinetic chain movement, the movement of one joint does not predict the movement of any other joints in the segment. Open kinetic chain movements include the swing phase of the leg during walking and kicking activities. Closed kinetic chain movements include the stance phase of walking and pushing movements with the arms or legs. Most complex human movements, such as walking or running, consist of sequences of open and closed kinetic chain movements that are at least partially dependent on propriocep tive processes. Sherrington (29) defined proprioception as knowledge of the positions and actions of parts of the body JOSPT Volume 28 Number 2 August 1998

It is important to establish whether presumed differences among varieties of motor responses are manifested in related differences in performance. In order to determine possible functional distinctions between closed and open kinetic chain tasks, participants' performance in the presence or absence of cognitive distraction on an error-detection task was assessed. Individual testing of participants consisted of knee extension and flexion movements to experimenter-defined positions, approximating the 25th, 50th, and 75th percentile of the participants' range of motion on the apparatus. Performance under conditions of distraction was significantly worse than in the absence of distraction. Performance using longer movements was significantly more accurate. No substantial differences were found between closed and open kinetic chain movements. Limitations of this research for the distinction between open and closed chain tasks are addressed, and clinical implications of the effects of distraction are presented.

Key Words: proprioception, kinetic chain, knee, movement

' Faculty Member, Smyer Independent School District, Smyer, TX. At the time this study was conducted, Mr. Taylor was a graduate research assistant, Department of Psychology, Texas Tech University, lubbock, TX.

* Professor, Department of Psychology, Texas Tech University, Box 42051, lubbock, TX 79409-2051;

Adjunct Research Scientist, Department of Physical Therapy, School of Allied Health, Texas Tech University Health Sciences Center, lubbock, TX Research Psychologist, Air Force Research laboratory, Mesa, AZ. At the time this study was conducted, Dr. Dunlap was a graduate research assistant, Department of Psychology, Texas Tech University, lubbock, TX. Assistant Professor and Regional Chairman, Department of Physical Therapy, School of Allied Health, Texas Tech University Health Sciences Center, Odessa, TX; Adjunct Assistant Professor, Department of Psychology, Texas Tech University, Lubbock, TX Assistant Professor, Department of Physical Therapy, School of Allied Health, Texas Tech University Health Sciences Center, lubbock, TX This research was supported by a grant from the South Plains Foundation, lubbock, TX.

from perceived sensations. Proprioception entails the integration of sensations from joint capsules, skin, tendons, ligaments, and muscles (21,24), and information received from proprioceptors are used in controlling human movements. For example, Adams (1) proposed a closed loop theory of motor learning in which proprioceptive feedback provides the

basis for comparison of the present movement to an internal standard or perceptual trace. Successful motor performance, according to the closed loop theory, requires monitoring feedback received during the movement, comparing it with the percep tual trace, and using it to guide the ongoing movement. Once feedback from the ongoing movement is

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judged to be equal to the perceptual trace, the movement is stopped at that location. Previous studies of human proprioceptive ability at the knee joint have used nonweight-bearing, open kinetic chain tasks (2,3,22,30,34),and most rehabilitation following knee injuries has also primarily used open kinetic chain tasks (15). Open kinetic chain movements have been found to isolate specific muscles and produce increased strain on the anterior cruciate ligament in extension movements and on the posterior cruciate ligament in flexion movements compared with similar closed kinetic chain movements (6). Closed kinetic chain tasks, having been found to produce significantly less strain in the cruciate ligaments d u e to the use of multiple muscle groups, have recently been recommended for knee rehabilitation (6,13,15,35,36). Closed kinetic chain tasks are also more identified with weight-bearing tasks commonly encountered by individuals doing typical daily activities (15). Limited research has examined performance differences between open and closed kinetic chain tasks, and this could be a productive focus of investigation, given the biomechanical differences between these types of movements. The increased use of multiple muscle groups and decreased strain of the cruciate ligaments during closed kinetic chain tasks may provide functionally different proprioceptive feedback to an individual when compared to open kinetic chain tasks with limited numbers of muscle groups involved and increased forces on the cruciate ligaments. If performance differences on a variety of tasks are found, it would be empirical support for a functional distinction between open and closed kinetic chain movements. On the other hand, finding no performance differences between closed and open kinetic chain tasks would diminish the utility of a distinction between the two.

Regardless of the nature of the tasks, individuals often d o not give full attention to them, and distraction, even in small amounts, is not unusual in most functional life experiences such as walking, climbing stairs, and avoiding obstacles. This lack of attention also may be due, in part, to many tasks having become automatic after many years of practice and, thus, not needing full attentional resources for successful execution. In any event, the effects of cognitive distraction on motor performance have been studied very little. Previous investigations of short-term memory for motor tasks under conditions of cognitive distraction have predominantly consisted of open kinetic chain movements at various retention intervals, where reproduction of either experimenterdefined movements (8,23) or participantdefined movements has been required (7.18). In these studies, cognitive distraction has been used during the retention interval period between the initial and reproduced movements. Cognitive tasks consisting of classifying numbers as low, high, even, and odd for 7 seconds following movements have produced retention loss (23) and significantly larger variable and constant error measurements (8). Voluntary movements have been found to be disrupted by information processing activities, such as counting and subtracting (7,18), indicating the disruption of motor programs by additional processing activities (22). As for effects of distraction on concurrent motor performance, Lee and Kelso (14) found decrements in the accuracy of proprioceptive judgments when concurrent cognitive tasks were performed in an open kinetic chain task. In that study, participants were asked to identify correctly a previously presented elbow joint angle under conditions of distraction consisting of a concurrent counting task. The ability to correctly identify testing angles was consistently less accurate for the distraction group when participants performed the con-

current task for longer periods (up to 150 seconds). Wells et al (34) found knee joint position matching in an open kinetic chain task to be significantly worse under conditions of concurrent distraction. Participants had their right knee positioned to angles of 45, 60, and 80" of flexion from a starting location of 35" of flexion and were asked to match the knee angle position with their left leg. When participants were required to perform mathematical calculations during the passive positioning of their knee, accuracy decreased significantly only at the larger testing angle of 80". In one recent study, Camicioli et al (4) have found that talking while walking can be a sufficient distractor for some groups of elderly individuals. Walking, however, involves a combination of closed and open kinetic chain segments, so it is unclear from that study whether closed and open chain segments are differentially affected by distraction. The investigation into the differences between closed and open chain function under distraction conditions is also merited from a clinical standpoint. In a clinical setting, distraction could produce consequences during both the evaluation and clinical treatment phases of rehabilitation. During the evaluation phase, the negative influence of distraction may cause the clinician to underestimate the patient's true functional capabilities. During the treatment phase of rehabilitation, the influence of distraction could have either a positive or a negative effect. The presence of distraction may compromise balance, coordination, and motor planning, placing an already vulnerable patient at a higher risk of injury during treatment. On the other hand, the introduction of a controlled distraction may provide a positive influence on the development of motor skills as the patient advances in the rehabilitation process by providing practice under more realistic and varied conditions. Volume 28 Number 2 August 1998 JOSFT

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Previous investigations of the effects of cognitive activities on concurrent motor performance have used only open kinetic chain movements (14,34) or tasks involving a combination of the two. Isolated closed kinetic chain movements performed under distraction conditions have not been examined previously and, thus, research comparing separate and distinct closed and open kinetic chain movements under conditions of additional cognitive distraction seems warranted. Therefore, the purpose of the present study was to compare errordetection performance during closed vs. open kinetic chain tasks.

METHOD In the present study, the tasks were developed based on previous research on errordetection processes (16,17). We used errordetection tasks developed to reflect the role of proprioceptive feedback in the monitoring process (1). On these tasks, individuals may be considered to compare incoming proprioceptive feedback against a standard estab lished from a previous movement. In addition to the manipulation of the type of movements (closed vs. open kinetic chain movements), the presence of distraction and the type (flexion or extension) and length (25th, 50th, and 75th percentile of the range of motion) of the original movement also were manipulated.

from the trials in each condition was used as the dependent variable.

Participants

R E S E A R C H - S- T U D Y

or experiencing current serious injuries to the knees, back, or ankles. There was no specific auditory screening, but neither was there any indication that any of the participants had hearing difficulties. Finally, participants were not recruited on the basis of any previous resistance training or rehabilitation experience.

Thirty-two right-handed, apparently healthy, undergraduate students (16 males and 16 females, average age of 19.36 years) from Texas Tech University, Lubbock, TX,volunteered to participate for course credit after Apparatus and Materials having signed Institutional Review Board-approved informed consent A Total ~ ~ (Sanr Diego, n CA) ~ ~ forms. In order to simplify and facili- exercise machine was used as the tate experimenter adjustments of closed kinetic chain apparatus. Particmovement specifications on each ipants were required to lie on their piece of apparatus, all participants backs on a sled mounted on a track. had heights falling between the 25th The sled could be pushed up (with and 75th percentiles of their respectheir legs) or allowed to slide down tive genders (11). A brief self-report the track (Figure, closed kinetic procedure was used to exclude p e chain). Since moderate stress on tential participants having a history joint structures has been found to

CKCTask

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Design A 2 (gender) X 2 (closed or open chain movement) X 2 (distraction or nondistraction) x 2 (session) X 2 (extension or flexion movement) x 3 (length of initial movement) X 2 (shorter or longer alternative movement) X 2 (test movement equal to target movement came first or second on test trials) mixed-factorial design was used with gender and type of task (closed or open chain) as the only between-subject variables. The percentage of correct judgments

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OKC Task FIGURE. Depictions of the apparatus and electrogoniometer placements used in the closed kinetic chain (CKC) and the open kinetic chain (OKC) tasks.

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increase discharge of joint, muscle, and cutaneous receptors (5). a 12" incline above the horizontal was used to provide moderate stress on joint structures for each participant, with forces equaling 20.8% of their individual body weight determined through trigonometric ratios. Each participant performed this action with his or her right leg only. The left leg was suspended in a sling to reduce additional proprioceptive feedback from the use of two legs. Extension movements started from approximately 90" of knee flexion, while flexion movements started from a position of approximately full extension (0" of knee flexion). An open chain exercise table was used for open kinetic chain movements. On this apparatus, the participant sat in a semi-reclined position with both legs free to move (Figure, open kinetic chain), but only the right leg was required to do so. Extension movements started from a position of 80" of knee flexion. Due to the participant's seated position, flexion movements started from a position of approximately 20" short of full extension (20" of knee flexion). Moderate stress on joint structures surrounding the knee was provided by a weight equaling 5% of each participant's individual total body weight being placed on the isotonic arm of the open chain exercise table. All open and closed kinetic chain movements consisted of a 90" range of motion. Concurrent cognitive distraction was achieved by an auditory shadowing task requiring participants to repeat information heard from a taped lecture through a set of earphones. The participants were required to repeat out loud every word of the lecture as they heard it. Anecdotally, this is a demanding and difficult task even when done by itself. Auditory information from the earphones was only heard in the left ear to allow participants to listen for commands given by the experimenter.

Procedure All participants were tested individually in two 30-minute sessions at least 1 day, but no more than 1 week, apart. Half of the participants (ie., eight males and eight females) performed open kinetic chain movements during the two sessions, while the remaining participants performed closed kinetic chain movements during the two sessions. Each participant performed these movements with the addition of an auditory shadowing distracter task in one session, while in the other session, no specific distraction was experienced. Half of the participants in each group had the distraction trials followed by no distraction trials, and the other half received the reverse order. When used, the auditory shadowing task was performed continuously by the participant from the time the instructions ended through to the end of the task. There was no pause or break in the task except that imposed by the participant to give his/her response (see below). Each session consisted of movements beginning from two starting locations (ie., legs fully extended or flexed) on the Total Gym exercise machine or the open chain exercise table. Each trial sequence consisted of three movements and began with the blindfolded participant making an initial movement followed by two test movements. Participants began each trial at the starting location and moved until they reached an experimenterdefined position at which time movement was blocked with a stop. This movement was the target movement from which the future judgment for that trial was made. Three target locations representing the 25th, 50th, and 75th percentile of the participant's range of motion were used for extension and flexion target movements. Following the initial target movement, the participant returned the right leg to the starting location. This was immediately followed by two successive test movements. These con-

sisted of one movement that was equal to the target distance and another movement that was either to a position slightly longer (+15%) or shorter (-15%) than the target location. Half of the test sequences consisted of the target movement distance presented first, and half of the sequences consisted of the target movement being presented second. The sequence of combinations of these test conditions was randomly determined. After the second test movement, the participant decided and indicated by an oral response of "first" or "second" which of the two test movements was the same as the initial target movement.

The data collected from each participant consisted of the percentage of correct responses under each of the conditions. These data were entered into an analysis of variance following the design shown above. That analysis yielded a significant main effect for distraction, q1.24) = 32.88, p < .001, with lower levels of performance present under conditions of concurrent cognitive distraction (a mean of 60.35% correct under distraction and 70.77% under no distraction). The main effect for target movement, F(2,48) = 26.39, p < .001, was also significant, with performance on longer movements significantly more accurate than shorter movements, with the mean percentage of correct responses being 57.5% (short, 25th percentile), 67% (medium, 50th percentile), and 72% (long, 75th percentile), respectively. A significant two-way interaction between the type of movement (ie., closed or open kinetic chain) and the alternative movement (ie., shorter or longer than the target movement) also was obtained, F( 1.24) = 5.73, P < .05. A simple effects test showed that only in the open kinetic chain condition did alternative movement length have an effect, F(1,15) = 11.0, p < .01. Volume 28 Number 2 August 1998 JOSPT

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Decisions were less accurate when the alternative movement was shorter than the target movement (61% for shorter alternatives vs. 73% for longer alternatives). In the closed kinetic chain condition, alternative movement lengths resulted in essentially the same level of performance (65% for shorter alternatives vs. 63.8% for longer alternatives). For the record, several higher order interactions (one even among six variables) involving procedural variables, such as order of presentation and choice of alternative movement on the test trials (ie., shorter or longer), also were significant, but they add little to the issues under investigation.

DISCUSSION This study provides a preliminary comparison of errordetection abilities during open and closed kinetic chain tasks, with or without concurrent cognitive processing. The main effect for closed vs. open kinetic chain movements was not found to be significant, in spite of the reported differences between the actions of the cruciate ligaments during closed and open kinetic chain movements. Given the different mechanics of closed and open kinetic chain movements of the knee joint, we hypothesized that these differences might have had an effect on participants' errordetection performance. It is noteworthy in this regard that Kramer et a1 (10) have demonstrated a tendency for greater reliability and less error during an open as opposed to a closed kinetic chain task. There was, however, little support for that hypothesis. One could argue that actual differences might still exist, but our errordetection task might not have been sensitive enough to detect them. Arguing against that possibility is the observation that performance levels have no hint of floor or ceiling effects. Participants' moderate performance levels leave plenty of room to observe greater and lesser levels of JOSPT Volume 28 Number 2

August 1998

performance that would be indicative of real differences. Concurrent cognitive activity did significantly reduce the accuracy of detecting the correct position of the target. A main effect of distraction was achieved, and there were no interactions between distraction and any other factors. An interaction between distraction and type of movement was considered possible, given the biomechanical differences between the open and closed chain tasks used. The lack of distraction interactions, however, may just be limited to individuals with "healthy knees" and may in fact appear in clinical populations in future studies. The mechanism and locus of the distraction main effect in this study cannot be determined easily. The shadowing task was performed throughout the session and might have interfered with the initial acquisition of the representation of the movement or might have interfered with the process of comparison between the memory of the target movement and the alternative test movements. This could be investigated in future research, with distraction experienced during different stages of the task (eg., during the original acquisition of the target movement, during the test phase, or both) in order to locate where distraction might play a role. Further, it is unclear from the present study what the actual distraction mechanism might have been. Certainly, the participants had a secondary task imposed on their primary task of motor error detection, but distraction might have exerted its effects by several mechanisms. Distraction might have reduced the amount of information processing capacity available to the participants so as to interfere with movement information being perceived, encoded, stored, or retrieved. Or the auditory nature of the distraction manipulation might have diminished the quality of important auditory feedback that would otherwise have been received from the sounds

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generated by the movement of the apparatus. These diminished "percep tual traces," as Adams (1) calls them, could have resulted in the poorer performance observed under distraction. Perhaps another study in which noninformative "white noise" was heard instead of the shadowing task would help to determine if the distraction effect mechanism was more perceptual than cognitive in nature. In any event, the distraction manipulation, though substantial in i ~ own s right, did not differentially affect the closed and open chain tasks. Previous findings of increased accuracy for longer movements (8,9, 12,18-20.32) were replicated. As the length of the movement increased, so did the accuracy of errordetection judgments. Short movements have

The main effect for closed vs. open kinetic chain movements was not found to be significant. previously been found to be much more dependent on the availability of central processing capacity (8,18,23, 33). The significant detrimental effects of concurrent cognitive distraction for shorter movement lengths seem to support their increased need for central processing in processing proprioceptive information. The results obtained in the present study are inconsistent with the results obtained by Wells et al (34) in an open kinetic chain concurrent processing task. They obtained decreased accuracy in knee joint position matching for longer movements but only investigated knee flexion movements of a limited range (ie., 45"). The present study used a 90" range of motion during knee extension and flexion movements,

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which more thoroughly approximates the range encountered by individuals doing typical daily activities. Many movements of the knee joint in reallife activities begin from a fully extended (eg., standing) or substantially flexed (eg., seated) position. The starting position of 35" of flexion used by Wells et al seems to be an arbitrary. position from which to start and may have influenced participants' performance levels at the three movement lengths used (ie., 45, 60, and 80" of flexion). These factors may have led them to an incomplete depiction of the total relationship between movement distance and accuracy. Another possible reason for differences in the results o h tained in the current study and those obtained by Wells et al (34) is the type of movement used. Wells et al used passive positioning of the right leg, and they asked each participant actively to move his or her left leg to match the position of the right leg, with vision of their lower limbs occluded by a curtain. The tasks used here had active positioning of the leg in both open and closed kinetic chain tasks. Active positioning of the leg across all movements within a trial may provide more propriocep tive information or better analyses and use of what information is provided than the slow, passive positioning used by Wells et al. The finding of an overall distraction effect may have certain clinical implications for both evaluation and treatment phases of rehabilitation. If a patient's performance was affected negatively by distraction (ie., not a true reflection of the patient's capabilities) during the evaluation phase, the patient's status might be misinterpreted by the clinician. Such an assessment error could lead to a misguided treatment prescription by the clinician and/or a prolonged rehabilitation process. Further, there could be several effects of distraction during the treat-

ment phase. A sufficient level of distraction encountered during attempted performance in the early stages of treatment (such as after surgery or in the acute stage after trauma) could jeopardize the patient's well-being. Patients in this condition are typically aroused or they are in an energized state with heightened heart rate, sweating, and alertness (25). Heightened arousal and distractibility could lead to disproportionate attention paid to irrelevant cues during m k performance (27). This could compromise balance, coordination, and control, leading to a greater risk of injury at those times when a patient's functional status is impaired. Distraction, if its introduction is controlled, could, on the other hand, have a beneficial effect later on in

A sufficient level of distraction encountered during attempted performance in the early stages of treatment could jeopardize the pa tient's well-being. .-the rehabilitation process. Introducing distraction (eg., in the form of simple conversation) during the performance of a specific task could be a source of variation of incoming environmental stimuli that would force the development of more effective information processing (28) and the initiation of appropriate motor programs (26), both of which contribute to the advancement in motor skill acquisition, development, and automaticity.

CONCLUSION We sought to determine if there were functional differences between closed and open kinetic chain error detection tasks and whether the two types of tasks were affected similarly or differently by cognitive distraction. There was little to indicate substantial functional differences between the open and closed kinetic chain movements used in this study. The distinct biomechanical differences between open and closed kinetic chain movements, in fact, may not lead to s u b stantial differences in errordetection ability. A possible explanation for the results found here may be the redundancy of feedback received from receptors in the joint capsule, skin, tendons, ligaments, and muscles. For healthy, intact individuals, this information may be combined in such ways as to provide comparable useful amounts of information regardless of the type of movement. Open and closed kinetic chain differences may be more detectable following a variety of reconstructions (eg., anterior cruciate ligament, total knee arthroplasty), where specific structures contributing to proprioception are either modified or are totally absent. The results were clear, however, in pointing out the potential detrimental effects of cognitive distraction on the types of motor activities represented in this study. JOSFT

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system depend on kinesthetic information to control natural limb movements? Behav Brain Sci 15:6 14-632, 1992 6. Henning CE, Lynch MA, Glick KR: An in vivo strain gauge study of elongation of the anterior cruciate ligament. Am 1 Sports Med 13:22-26, 1985 7. Jones B: Role of central monitoring of efference in short-term memory for movements. / Exp Psychol 102: 37-43, 1 974 8. Kelle SW, Ells /G: Memory characteristics of kinesthetic information. / Mot Behav 4: 127- 134, 1972 9. Kelso /AS, Holt Kl, Flatt AE: The role of proprioception in the perception and control of human movement: Toward a theoretical reassessment. Percept Psychophysics 28:45-52, 1980 10. Kramer 1, Birmingham T, Forwell L, Kiefer G, Handfield T: Comparisons of weight-bearing and non-weight-bearing tests of knee proprioception performed by patients with patello- femoraI pain syndrome and asymptomatic individuals. Clin / Sports Med 7: 1 13- 118, 1997 1 1. Kroemer K: Engineering anthropometry. Ergonomics 32:767-784, 1989 12. Laabs GI: Retention characteristics of different reproduction cues in motor short-term memory. I Exp Psychol 100: 168-177, 1973 13. Lattanza L, Gray GW, Kantner RM: Closed versus open chain measurements of subtalar joint eversion: Implications for clinical practice. / Orthop Sports Phys Ther 9:3 10-3 7 4, 1988 14. Lee WA, Kelso /AS: Properties of slowly adapting joint receptors do not readily predict perception of limb position. / Human Movement Studies 5: 171-1 8 1, 1979

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26. Schmidt RA: The acquisition of skill: Some modifications to the perceptionaction relationship through practice. In: Heuer H, Sanders AF (eds), Perspectives on Perception and Action, pp 77103. Hillsdale, Nl: Lawrence Erlbaum Associates, Inc., 1987 27. Schmidt RA: Motor Control and Learning (2nd Ed), Champaign: Human Kinetic Publishers, Inc., 1988 28. Schneider W: Training high-performance skills: Fallacies and guidelines. Hum Factors 27:285-300, 1985 29. Sherrington CS: O n the proprioceptive system, especially in its refley aspects. Brain 29:467-482, 1906 30. Skinner HB, Barrack RL, Cook SD, Haddad Rl: Joint position sense in total knee arthroplasty. / Orthop Res 1:276283, 1984 3 1. Steindler A: Kinesiology of the Human Body Under Normal and Pathological Conditions, Springfield, IL: Charles Thomas, 1955 32. Stelmach GE, Diggles VA: Control theories in motor behavior. Acta Psychol 5O:83- 105, 1 982 33. Stelmach GE, Wilson M: Kinesthetic retention, movement extent, and information processing. / Exp Psychol 85: 425-430, 1970 34. Wells 1, Kurki M, Ruston S: Effect of a concurrent cognitive demand on knee position matching. Physiotherapy 80: 7.57-76 1, 1994 35. Worrell TW, Borchert B, Erner K, Fritz], Leerar P: Effect of a lateral step-up exercise protocol on quadriceps and lower extremity performance. / Orthop Spom Phys Ther 18: 646-653, 1993 36. Yack HI, Collins CE, Whieldon TI: Comparison of closed and open kinetic chain exercises in the anterior cruciate ligament-deficient knee. Am / Sports Med 21:49-54, 1993