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Yacoubi B, Christou EA. Motor Output Variability in Movement Disorders: Insights From Essential Tremor. Exerc Sport Sci Rev 2024; 52:95-101. [PMID: 38445865 DOI: 10.1249/jes.0000000000000338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2024]
Abstract
Findings on individuals with essential tremor suggest that tremor (within-trial movement unsteadiness) and inconsistency (trial-to-trial movement variance) stem from distinct pathologies and affect function uniquely. Nonetheless, the intricacies of inconsistency in movement disorders remain largely unexplored, as exemplified in ataxia where inconsistency below healthy levels is associated with greater pathology. We advocate for clinical assessments that quantify both tremor and inconsistency.
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Choi YJ, Chalatzoglidis G, Trapezanidou M, Delmas S, Savva E, Yacoubi B, Arabatzi F, Christou EA. Adolescent boys who participate in sports exhibit similar ramp torque control with young men despite differences in strength and tendon characteristics. Eur J Appl Physiol 2023; 123:965-974. [PMID: 36607415 PMCID: PMC10718087 DOI: 10.1007/s00421-022-05130-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 12/26/2022] [Indexed: 01/07/2023]
Abstract
PURPOSE The goal of this paper was to determine if sports participation influences torque control differently for adolescent boys and young men during a slow ramp task. METHODS Twenty-one adolescent boys (11 athletes) and 31 young men (16 athletes) performed a slow ramp increase in plantar flexion torque from 0 to maximum. We quantified torque control as the coefficient of variation (CV) of torque during the ramp and quantified the Achilles tendon mechanical properties using ultrasonography. RESULTS Relative to adolescent boys, young men were taller, heavier, stronger, and had a longer and stiffer Achilles tendon. However, these characteristics were not different between athletes and non-athletes in adolescent boys. For the CV of torque, there was a significant interaction with sports participation, indicating that only adolescent boys who were non-athletes had greater variability than young men. The CV of torque of all participants was predicted from the maximum torque and torque oscillations from 1 to 2 Hz, whereas the CV of torque for adolescent boys was predicted only from torque oscillations from 1 to 2 Hz. CONCLUSION These findings suggested that adolescent boys who participate in sports exhibited lower torque variability during a slow ramp task, which was not explained by differences in Achilles tendon properties or strength.
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Affiliation(s)
- Yoon Jin Choi
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, 32611-8205, USA
| | - George Chalatzoglidis
- Laboratory of Neuromechanics, Department of Physical Education and Sports Science at Serres, Aristotle University of Thessaloniki, Serres, Greece
| | - Martha Trapezanidou
- Laboratory of Neuromechanics, Department of Physical Education and Sports Science at Serres, Aristotle University of Thessaloniki, Serres, Greece
| | - Stefan Delmas
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, 32611-8205, USA
| | - Evangelia Savva
- Laboratory of Neuromechanics, Department of Physical Education and Sports Science at Serres, Aristotle University of Thessaloniki, Serres, Greece
| | - Basma Yacoubi
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, 32611-8205, USA
| | - Fotini Arabatzi
- Laboratory of Neuromechanics, Department of Physical Education and Sports Science at Serres, Aristotle University of Thessaloniki, Serres, Greece
| | - Evangelos A Christou
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, 32611-8205, USA.
- Department of Neurology, Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, USA.
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Patterns of Movement Performance and Consistency From Childhood to Old Age. Motor Control 2022; 27:258-274. [PMID: 36351427 DOI: 10.1123/mc.2022-0006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Revised: 09/01/2022] [Accepted: 09/07/2022] [Indexed: 11/11/2022]
Abstract
It is widely accepted that the general process of aging can be reflected by changes in motor function. Typically, optimal performance of a given motor task is observed for healthy young adults with declines being observed for individuals at either end of the lifespan. This study was designed to examine differences in the average and variability (i.e., intraindividual variability) of chewing, simple reaction time, postural control, and walking responses. For this study, 15 healthy children, 15 young adults, and 15 older adults participated. Our results indicated the movement performance for the reaction time and postural sway followed a U shape with young adults having faster reaction times and decreased postural sway compared to the children and older adults. However, this pattern was not preserved across all motor tasks with no age differences emerging for (normalized) gait speed, while chewing rates followed a U-shaped curve with older adults and children chewing at faster rates. Taken together, these findings would indicate that the descriptive changes in motor function with aging are heavily influenced by the nature of the task being performed and are unlikely to follow a singular pattern.
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Fahr A, Keller JW, Balzer J, Lieber J, van Hedel HJA. Quantifying age-related differences in selective voluntary motor control in children and adolescents with three assessments. Hum Mov Sci 2021; 77:102790. [PMID: 33798928 DOI: 10.1016/j.humov.2021.102790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 03/25/2021] [Accepted: 03/26/2021] [Indexed: 10/21/2022]
Abstract
BACKGROUND Neurophysiological development of selective voluntary motor control (SVMC) is assumed but has not been quantified objectively. We assessed SVMC with (i) clinical assessments, (ii) a combination of these assessments with surface electromyography (sEMG) and, (iii) a playful computer game. The aim of this study was to describe and compare age-related differences in SVMC, quantified with these tools, in neurologically intact children, adolescents, and adults. METHODS We measured upper and lower extremity SVMC with three assessments in 31 children and adolescents. A sample of 33 and 31 adults provided reference values for the upper and lower extremity assessments, respectively. The Selective Control of the Upper Extremity Scale (SCUES) or the Selective Control Assessment of the Lower Extremity (SCALE) were combined with simultaneous sEMG recordings. We quantified SVMC by a similarity index that compared an individual's muscle activation pattern with those of an adult reference group. The SVMC Assessgame required isolated joint movements to steer an avatar and quantified the accuracy of the selective movement and the extent of involuntary movements occurring in not involved joints. RESULTS Results from the conventional clinical assessments correlated low to moderately with age (SCUES: r = 0.55, p = 0.013; SCALE: r = 0.44, p = 0.001), while the correlation between the sEMG based similarity index and age was negligible (r ≤ 0.25). The outcomes of the Assessgame correlated highly with age (r ≥ 0.80, p ≤ 0.001). Older children and adolescents performed movements more accurately and with fewer involuntary movements compared to younger participants. CONCLUSIONS The tools assess and quantify SVMC differently, affecting the way they capture age-related differences in SVMC. Some assessments require reference values from neurologically intact children and adolescents to correctly classify impairments of SVMC in patients with neuromotor disorders.
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Affiliation(s)
- Annina Fahr
- Swiss Children's Rehab, University Children's Hospital Zurich, Mühlebergstrasse 104, 8910 Affoltern am Albis, Switzerland; Children's Research Center, University Children's Hospital Zurich, University of Zurich, Steinwiesstrasse 75, 8032 Zürich, Switzerland; ETH Zurich, Rämistrasse 101, 8092 Zurich, Switzerland.
| | - Jeffrey W Keller
- Swiss Children's Rehab, University Children's Hospital Zurich, Mühlebergstrasse 104, 8910 Affoltern am Albis, Switzerland; Children's Research Center, University Children's Hospital Zurich, University of Zurich, Steinwiesstrasse 75, 8032 Zürich, Switzerland; Doctoral Program Clinical Science, Faculty of Medicine, University of Zurich, University of Zurich Dean's Office Office of the Board of Directors of the Academic Medicine Zurich (UMZH), Pestalozzistrasse 3/5, 8091 Zurich, Switzerland.
| | - Julia Balzer
- Swiss Children's Rehab, University Children's Hospital Zurich, Mühlebergstrasse 104, 8910 Affoltern am Albis, Switzerland; Children's Research Center, University Children's Hospital Zurich, University of Zurich, Steinwiesstrasse 75, 8032 Zürich, Switzerland.
| | - Jan Lieber
- Swiss Children's Rehab, University Children's Hospital Zurich, Mühlebergstrasse 104, 8910 Affoltern am Albis, Switzerland; Children's Research Center, University Children's Hospital Zurich, University of Zurich, Steinwiesstrasse 75, 8032 Zürich, Switzerland.
| | - Hubertus J A van Hedel
- Swiss Children's Rehab, University Children's Hospital Zurich, Mühlebergstrasse 104, 8910 Affoltern am Albis, Switzerland; Children's Research Center, University Children's Hospital Zurich, University of Zurich, Steinwiesstrasse 75, 8032 Zürich, Switzerland.
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Motor Control and Achilles Tendon Adaptation in Adolescence: Effects of Sport Participation and Maturity. J Hum Kinet 2021; 76:101-116. [PMID: 33603928 PMCID: PMC7877283 DOI: 10.2478/hukin-2021-0003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
An important but unresolved research question in adolescent children is the following: “Does sport participation interact with maturation to change motor control and the mechanical and morphological properties of tendons?” Here, we address this important research question with a longitudinal study around the age of peak height velocity (PHV). Our purpose was to characterize the interactive effects of maturation and sports participation on motor control and the mechanical and morphological properties of the Achilles tendon (AT) in adolescent athletes and non-athletes. Twenty-two adolescent athletes (13.1 ± 1.1 years) and 19 adolescent non-athletes (12.8 ± 1.1 years) volunteered for this study. We quantified motor control as the coefficient of variation of torque during a ramp task. In addition, we quantified the AT morphological and mechanical properties using ultrasonography from 18 months before to 12 months after PHV. We found that motor control improved with maturation in both athletes and non-athletes. We found that athletes have a greater increase in body mass with maturation that relates to greater plantarflexion peak force and AT peak stress. Also, athletes have a thicker and longer AT, as assessed with resting cross-sectional area and length. Although the rate of increase in the morphological change with maturation was similar for athletes and non-athletes, the rate of increase in normalized AT stiffness was greater for athletes. This increased AT stiffness in athletes related to peak force and stress. In summary, maturation improves motor control in adolescent children. Further, we provide novel longitudinal evidence that sport participation interacts with maturation in adolescents to induce adaptive effects on the Achilles tendon morphology and mechanical properties. These findings have the potential to minimize the risk of injuries and maximize athletic development in talented adolescents.
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Casamento-Moran A, Fleeman R, Chen YT, Kwon M, Fox EJ, Yacoubi B, Christou EA. Neuromuscular variability and spatial accuracy in children and older adults. J Electromyogr Kinesiol 2018; 41:27-33. [PMID: 29723799 DOI: 10.1016/j.jelekin.2018.04.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 03/27/2018] [Accepted: 04/23/2018] [Indexed: 10/17/2022] Open
Abstract
Our ability to control movements is influenced by the developmental status of the neuromuscular system. Consequently, movement control improves from childhood to early adulthood but gradually declines thereafter. However, no study has compared movement accuracy between children and older adults. The purpose of this study was to compare endpoint accuracy during a fast goal-directed movement task in children and older adults. Ten pre-adolescent children (9.7 ± 0.67 yrs) and 19 older adults (71.95 ± 6.99 yrs) attempted to accurately match a peak displacement of the foot to a target (9° in 180 ms) with a dorsiflexion movement. We recorded electromyographic activity from the tibialis anterior (agonist) and soleus (antagonist) muscles. We quantified position error (i.e. spatial accuracy) as well as the coordination, magnitude, and variability of the antagonistic muscles. Children exhibited greater position error than older adults (36.4 ± 13.4% vs. 27.0 ± 9.8%). This age-related difference in spatial accuracy, was related to a more variable activation of the agonist muscle (R2: 0.358; P < 0.01). These results suggest that an immature neuromuscular system, compared to an aged one, affects the generation and refinement of the motor plan which increases the variability in the neural drive to the muscle and reduces spatial accuracy in children.
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Affiliation(s)
| | - Rebecca Fleeman
- Department of Applied Physiology and Kinesiology, University of Florida, FL, USA.
| | - Yen-Ting Chen
- Department of Applied Physiology and Kinesiology, University of Florida, FL, USA.
| | - MinHyuk Kwon
- Department of Applied Physiology and Kinesiology, University of Florida, FL, USA.
| | - Emily J Fox
- Department of Physical Therapy, University of Florida, FL, USA.
| | - Basma Yacoubi
- Department of Applied Physiology and Kinesiology, University of Florida, FL, USA.
| | - Evangelos A Christou
- Department of Applied Physiology and Kinesiology, University of Florida, FL, USA; Department of Physical Therapy, University of Florida, FL, USA.
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Casamento-Moran A, Hunter SK, Chen YT, Kwon MH, Fox EJ, Yacoubi B, Christou EA. Sex differences in spatial accuracy relate to the neural activation of antagonistic muscles in young adults. Exp Brain Res 2017; 235:2425-2436. [DOI: 10.1007/s00221-017-4968-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 04/24/2017] [Indexed: 12/20/2022]
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Davies BL, Gehringer JE, Kurz MJ. Age-related differences in the motor planning of a lower leg target matching task. Hum Mov Sci 2015; 44:299-306. [PMID: 26519904 DOI: 10.1016/j.humov.2015.10.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 10/09/2015] [Accepted: 10/17/2015] [Indexed: 11/25/2022]
Abstract
While the development and execution of upper extremity motor plans have been well explored, little is known about how individuals plan and execute rapid, goal-directed motor tasks with the lower extremities. Furthermore, the amount of time needed to integrate the proper amount of visual and proprioceptive feedback before being able to accurately execute a goal-directed movement is not well understood; especially in children. Therefore, the purpose of this study was to initially interrogate how the amount of motor planning time provided to a child before movement execution may influence the preparation and execution of a lower leg goal-directed movement. The results displayed that the amount of pre-movement motor planning time provided may influence the reaction time and accuracy of a goal directed leg movement. All subjects in the study had longer reaction times and less accurate movements when no pre-movement motor planning time was provided. In addition, the children had slower reaction times, slower movements, and less accurate movements than the adults for all the presented targets and motor planning times. These results highlight that children may require more time to successfully plan a goal directed movement with the lower extremity. This suggests that children may potentially have less robust internal models than adults for these types of motor skills.
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Affiliation(s)
- Brenda L Davies
- Department of Physical Therapy, Munroe-Meyer Institute for Genetics and Rehabilitation, University of Nebraska Medical Center, Omaha, NE, United States
| | - James E Gehringer
- Department of Physical Therapy, Munroe-Meyer Institute for Genetics and Rehabilitation, University of Nebraska Medical Center, Omaha, NE, United States
| | - Max J Kurz
- Department of Physical Therapy, Munroe-Meyer Institute for Genetics and Rehabilitation, University of Nebraska Medical Center, Omaha, NE, United States.
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