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Markstrom, J.L.; Liebermann, D.G.; Schelin, L.; Hager, C.K. |
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Title |
Atypical Lower Limb Mechanics During Weight Acceptance of Stair Descent at Different Time Frames After Anterior Cruciate Ligament Reconstruction |
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Journal Article |
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Year |
2022 |
Publication |
The American Journal of Sports Medicine |
Abbreviated Journal |
Am J Sports Med |
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1-9 |
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Keywords |
Acl; biomechanics; functional data analysis; motion analysis; stepping down |
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Abstract |
BACKGROUND: An anterior cruciate ligament (ACL) rupture may result in poor sensorimotor knee control and, consequentially, adapted movement strategies to help maintain knee stability. Whether patients display atypical lower limb mechanics during weight acceptance of stair descent at different time frames after ACL reconstruction (ACLR) is unknown. PURPOSE: To compare the presence of atypical lower limb mechanics during the weight acceptance phase of stair descent among athletes at early, middle, and late time frames after unilateral ACLR. STUDY DESIGN: Controlled laboratory study. METHODS: A total of 49 athletes with ACLR were classified into 3 groups according to time after ACLR-early (<6 months; n = 17), middle (6-18 months; n = 16), and late (>18 months; n = 16)-and compared with asymptomatic athletes (control; n = 18). Sagittal plane hip, knee, and ankle angles; angular velocities; moments; and powers were compared between the ACLR groups' injured and noninjured legs and the control group as well as between legs within groups using functional data analysis methods. RESULTS: All 3 ACLR groups showed greater knee flexion angles and moments than the control group for injured and noninjured legs. For the other outcomes, the early group had, compared with the control group, less hip power absorption, more knee power absorption, lower ankle plantarflexion angle, lower ankle dorsiflexion moment, and less ankle power absorption for the injured leg and more knee power absorption and higher vertical ground reaction force for the noninjured leg. In addition, the late group showed differences from the control group for the injured leg revealing more knee power absorption and lower ankle plantarflexion angle. Only the early group took a longer time than the control group to complete weight acceptance and demonstrated asymmetry for multiple outcomes. CONCLUSION: Athletes with different time frames after ACLR revealed atypically large knee angles and moments during weight acceptance of stair descent for both the injured and the noninjured legs. These findings may express a chronically adapted strategy to increase knee control. In contrast, atypical hip and ankle mechanics seem restricted to an early time frame after ACLR. CLINICAL RELEVANCE: Rehabilitation after ACLR should include early training in controlling weight acceptance. Including a control group is essential when evaluating movement patterns after ACLR because both legs may be affected. |
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Department of Community Medicine and Rehabilitation, Physiotherapy, Umea University, Umea, Sweden |
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0363-5465 |
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PMID:35604127 |
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112 |
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Author |
Liebermann, D.G.; Biess, A.; Friedman, J.; Gielen, C.C.A.M.; Flash, T. |
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Title |
Intrinsic joint kinematic planning. I: reassessing the Listing's law constraint in the control of three-dimensional arm movements |
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Journal Article |
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Year |
2006 |
Publication |
Experimental Brain Research |
Abbreviated Journal |
Exp Brain Res |
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Volume |
171 |
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2 |
Pages |
139-154 |
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Keywords |
Adolescent; Adult; Analysis of Variance; *Arm; Biomechanics; Eye Movements/*physiology; Humans; Joints/*physiology; Male; Movement/*physiology; *Musculoskeletal System; Orientation/*physiology; Posture |
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This study tested the validity of the assumption that intrinsic kinematic constraints, such as Listing's law, can account for the geometric features of three-dimensional arm movements. In principle, if the arm joints follow a Listing's constraint, the hand paths may be predicted. Four individuals performed 'extended arm', 'radial', 'frontal plane', and 'random mixed' movements to visual targets to test Listing's law assumption. Three-dimensional rotation vectors of the upper arm and forearm were calculated from three-dimensional marker data. Data fitting techniques were used to test Donders' and Listing's laws. The coefficient values obtained from fitting rotation vectors to the surfaces described by a second-order equation were analyzed. The results showed that the coefficients that represent curvature and twist of the surfaces were often not significantly different from zero, particularly not during randomly mixed and extended arm movements. These coefficients for forearm rotations were larger compared to those for the upper arm segment rotations. The mean thickness of the rotation surfaces ranged between approximately 1.7 degrees and 4.7 degrees for the rotation vectors of the upper arm segment and approximately 2.6 degrees and 7.5 degrees for those of the forearm. During frontal plane movements, forearm rotations showed large twist scores while upper arm segment rotations showed large curvatures, although the thickness of the surfaces remained low. The curvatures, but not the thicknesses of the surfaces, were larger for large versus small amplitude radial movements. In conclusion, when examining the surfaces obtained for the different movement types, the rotation vectors may lie within manifolds that are anywhere between curved or twisted manifolds. However, a two-dimensional thick surface may roughly represent a global arm constraint. Our findings suggest that Listing's law is implemented for some types of arm movement, such as pointing to targets with the extended arm and during radial reaching movements. |
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Department of Physical Therapy, Sackler Faculty of Medicine, Tel-Aviv University, 69978, Ramat Aviv, Israel. dlieberm@post.tau.ac.il |
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0014-4819 |
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PMID:16341526 |
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Penn State @ write.to.jason @ |
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18 |
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Liebermann, D.G.; Goodman, D. |
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Title |
Pre-landing muscle timing and post-landing effects of falling with continuous vision and in blindfold conditions |
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Journal Article |
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Year |
2007 |
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Journal of Electromyography and Kinesiology : Official Journal of the International Society of Electrophysiological Kinesiology |
Abbreviated Journal |
J Electromyogr Kinesiol |
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17 |
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2 |
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212-227 |
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Keywords |
Adult; Analysis of Variance; Biomechanics; *Blindness; *Electromyography; Humans; Joints/physiology; Lower Extremity/physiology; Male; Movement/*physiology; Muscle, Skeletal/*physiology; Orientation; *Vision, Ocular |
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The present study examined the effect of continuous vision and its occlusion in timing of pre-landing actions during free falls. When vision is occluded, muscle activation is hypothesized to start relative to onset of the fall. However, when continuous vision is available onset of action is hypothesized to be relative to the moment of touchdown. Six subjects performed 6 randomized sets of 6 trials after becoming familiar with the task. The 36 trials were divided in 2 visual conditions (vision and blindfold) and 3 heights of fall (15, 45 and 75 cm). EMG activity was recorded from the gastrocnemius and rectus femoris muscles during the falls. The latency of onset (L(o)) and the lapse from EMG onset to touchdown (T(c)) were obtained from these muscles. Vertical forces were recorded to assess the effects of pre-landing activity on the impacts at collision with and without continuous vision. Peak amplitude (F(max)), time to peak (T(max)) and peak impulse normalized to momentum (I(norm)) were used as outcome measures. Within flight time ranges of approximately 50-400 ms, the results showed that L(o) and T(c) follow a similar linear trend whether continuous vision was available or occluded. However, the variability of T(c) for each of the muscles was larger in the vision occluded condition. Analyses of variance showed that the rectus femoris muscle started consistently earlier in no vision trials. Finally, impact forces were not different in vision or blindfold conditions, and thus, they were not affected by minor differences in the timing of muscles prior to landing. Thus, it appears that knowing the surroundings before falling may help to reduce the need for a continuous visual input. The relevance of such input cannot be ruled out for falls from high landing heights, but cognitive factors (e.g., attention to specific cues and anticipation of a fall) may play a dominant role in timing actions during short duration falls encountered daily. |
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Physical Therapy Department, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel. dlieberm@post.tau.ac.il <dlieberm@post.tau.ac.il> |
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1050-6411 |
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PMID:16600637 |
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37 |
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Author |
Roijezon, U.; Djupsjobacka, M.; Bjorklund, M.; Hager-Ross, C.; Grip, H.; Liebermann, D.G. |
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Title |
Kinematics of fast cervical rotations in persons with chronic neck pain: a cross-sectional and reliability study |
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Journal Article |
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Year |
2010 |
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BMC Musculoskeletal Disorders |
Abbreviated Journal |
BMC Musculoskelet Disord |
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11 |
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222 |
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Keywords |
Adult; Aged; Biomechanics/*physiology; Cervical Vertebrae/*physiopathology; Chronic Disease; Cross-Sectional Studies; Female; Head Movements/*physiology; Humans; Middle Aged; Neck Pain/*diagnosis/*etiology/physiopathology; Physical Examination/methods; Reproducibility of Results; Rotation/*adverse effects; Time Factors; Young Adult |
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BACKGROUND: Assessment of sensorimotor function is useful for classification and treatment evaluation of neck pain disorders. Several studies have investigated various aspects of cervical motor functions. Most of these have involved slow or self-paced movements, while few have investigated fast cervical movements. Moreover, the reliability of assessment of fast cervical axial rotation has, to our knowledge, not been evaluated before. METHODS: Cervical kinematics was assessed during fast axial head rotations in 118 women with chronic nonspecific neck pain (NS) and compared to 49 healthy controls (CON). The relationship between cervical kinematics and symptoms, self-rated functioning and fear of movement was evaluated in the NS group. A sub-sample of 16 NS and 16 CON was re-tested after one week to assess the reliability of kinematic variables. Six cervical kinematic variables were calculated: peak speed, range of movement, conjunct movements and three variables related to the shape of the speed profile. RESULTS: Together, peak speed and conjunct movements had a sensitivity of 76% and a specificity of 78% in discriminating between NS and CON, of which the major part could be attributed to peak speed (NS: 226 +/- 88 degrees /s and CON: 348 +/- 92 degrees /s, p < 0.01). Peak speed was slower in NS compared to healthy controls and even slower in NS with comorbidity of low-back pain. Associations were found between reduced peak speed and self-rated difficulties with running, performing head movements, car driving, sleeping and pain. Peak speed showed reasonably high reliability, while the reliability for conjunct movements was poor. CONCLUSIONS: Peak speed of fast cervical axial rotations is reduced in people with chronic neck pain, and even further reduced in subjects with concomitant low back pain. Fast cervical rotation test seems to be a reliable and valid tool for assessment of neck pain disorders on group level, while a rather large between subject variation and overlap between groups calls for caution in the interpretation of individual assessments. |
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Centre for Musculoskeletal Research, University of Gavle, Sweden. ulrik.roijezon@ltu.se |
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1471-2474 |
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PMID:20875135 |
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31 |
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Krasovsky, T.; Berman, S.; Liebermann, D.G. |
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Title |
Kinematic features of continuous hand reaching movements under simple and complex rhythmical constraints |
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Journal Article |
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2010 |
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Journal of Electromyography and Kinesiology : Official Journal of the International Society of Electrophysiological Kinesiology |
Abbreviated Journal |
J Electromyogr Kinesiol |
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20 |
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4 |
Pages |
636-641 |
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Keywords |
*Acoustic Stimulation; Adult; Biomechanics; *Cues; Female; Hand/*physiology; Humans; Male; Movement/*physiology |
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BACKGROUND: Auditory cues are known to alter movement kinematics in healthy people as well as in people with neurological conditions (e.g., Parkinson's disease or stroke). Pacing movement to rhythmical constraints is known to change both the spatial and temporal features of movement. However, the effect of complexity of pacing on the spatial and temporal kinematic properties is still poorly understood. The current study investigated spatial and temporal aspects of movement (path and speed, respectively) and their integration while subjects followed simple isochronous or complex non-isochronous rhythmical constraints. Spatiotemporal decoupling was expected under the latter constraint. METHODS: Ten subjects performed point-to-point hand movements towards visual targets on the surface of a hemisphere, while following continuous auditory cues of different pace and meter. The spatial and temporal properties of movement were compared to geodesic paths and unimodal bell-shaped speed profiles, respectively. Multiple two-way RM-ANOVAs (pace [1-2 Hz] x meter [duple-triple]) were performed on the different kinematic variables calculated to assess hand deviations from the model data (p< or = 0.05). RESULTS: As expected, increasing pace resulted in straighter hand paths and smoother speed profiles. Meter, however, affected only the path (shorter and straighter under triple) without significantly changing speed. Such an effect was observed at the slow pace only. CONCLUSIONS: Under simple rhythmic cues, an increase in pace causes spontaneous adjustments in spatial features (straighter hand paths) while preserving temporal ones (maximally-smoothed hand speeds). Complex rhythmical cues in contrast perturb spatiotemporal coupling and challenge movement control. These results may have important practical implications in motor rehabilitation. |
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Department of Physical and Occupational Therapy, Faculty of Medicine, McGill University, Canada |
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1050-6411 |
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PMID:20382031 |
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32 |
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