The Relationships Between Muscle Force Steadiness and Visual Steadiness in Young and Old Adults

Motor Control ◽  
2015 ◽  
Vol 19 (1) ◽  
pp. 60-74 ◽  
Author(s):  
Rebecca L. Krupenevich ◽  
Nick Murray ◽  
Patrick M. Rider ◽  
Zachary J. Domire ◽  
Paul DeVita
Keyword(s):  
Eye Movements ◽  
Force Control ◽  
Muscle Force ◽  
Age Groups ◽  
Quadriceps Muscle ◽  
Voluntary Contraction ◽  
Isometric Contractions ◽  
Old Adults ◽  
Visual Ability ◽  
Muscle Torque

Since vision is used in studies of muscle force control, reduced muscle force control might be related to reduced visual ability. We investigated relationships between steadiness in eye movements and quadriceps muscle torque (a surrogate for force) during isometric contractions of constant and varying torques. Nineteen young adults with an average age of 20.7 years and 18 old adults with an average age of 71.6 years performed three vision tasks, three vision and torque tasks at 40% maximal voluntary contraction (MVC), and three vision and torque tasks at 54 nm. Age groups had identical torque steadiness (CV) in 40%-MVC and 54-nm conditions (p > .05). Old had similar vertical (p > .05) but decreased horizontal visual steadiness (SD) (p < .05) compared with young. Correlations between visual steadiness and muscle torque steadiness failed to show a significant relationship (p > .05). We were unable to identify a substantial relationship between muscle torque steadiness and eye movement, as a component of visual steadiness, and conclude that reduced visual steadiness does not contribute to reduced muscle torque steadiness.

Perceived Exertion in Isometric Muscular Contractions Related to Age, Muscle, Force Level and Duration

1992 ◽  
Vol 36 (10) ◽  
pp. 712-716 ◽  
Author(s):  
Joseph M. Deeb ◽  
Colin G. Drury
Keyword(s):  
Perceived Exertion ◽  
Muscle Force ◽  
Age Groups ◽  
Muscle Group ◽  
Isometric Contractions ◽  
Age Group ◽  
Perceived Effort ◽  
Muscle Groups ◽  
Different Levels

This research was concerned with studying the development and growth of perceived effort of long-term isometric contractions as a function of muscle group (biceps vs quadriceps), of subjects with different age groups (20–29 vs. 50–59 years old) on long-term muscular isometric contractions (5 minutes) at different levels of %MVC (20, 40, 60, 80 and 100 %MVC). An experiment testing 20 subjects each performing 10 conditions (two muscle groups × five levels of %MVC) showed that the older age group reported Significantly higher perceived exertion at higher levels of %MVC and across time. Furthermore, subjects experienced a higher and faster increase in their perceived exertion when the level of %MVC and time increased.

Older adults are less steady during submaximal isometric contractions with the knee extensor muscles

2002 ◽  
Vol 92 (3) ◽  
pp. 1004-1012 ◽  
Author(s):  
Brian L. Tracy ◽  
Roger M. Enoka
Keyword(s):  
Maximum Voluntary Contraction ◽  
Knee Extensor ◽  
Voluntary Contraction ◽  
Eccentric Contractions ◽  
Isometric Contractions ◽  
Antagonist Muscle ◽  
Old Adults ◽  
Extensor Muscles ◽  
Young Subjects ◽  
Knee Extensor Muscles

This study compared the steadiness of submaximal contractions with the knee extensor muscles in young and old adults. Twenty young and twenty old subjects underwent assessment of isometric maximum voluntary contraction (MVC), one-repetition maximum (1-RM) strength, and steadiness during isometric, concentric, and eccentric contractions with the knee extensor muscles. The old adults displayed 33% lower MVC force and a 41% lower 1-RM load. The coefficient of variation for force was significantly greater for the old adults during isometric contractions at 2, 5, and 10% of MVC but not at 50% MVC. The decline in steadiness at low forces experienced by the men was marginally greater than that experienced by the women. The steadiness of concentric and eccentric contractions was similar in young and old adults at 5, 10, and 50% of 1-RM load. Old subjects exhibited greater coactivation of an antagonist muscle compared with young subjects during the submaximal isometric and anisometric contractions. These results indicate that, whereas the ability to exert steady submaximal forces with the knee extensor muscles was reduced in old adults, fluctuations in knee joint angle during slow movements were similar for young and old adults.

scholarly journals Bimodal recovery of quadriceps muscle force within 24 hours after sprint cycling for 30 seconds

Medicina ◽  
2007 ◽  
Vol 43 (3) ◽  
pp. 226 ◽  
Author(s):  
Albertas Skurvydas ◽  
Nerijus Masiulis ◽  
Danguolė Satkunskienė ◽  
Aleksas Stanislovaitis ◽  
Gedminas Mamkus ◽  
...  
Keyword(s):  
Muscle Force ◽  
Maximum Voluntary Contraction ◽  
Low Frequency ◽  
Muscle Length ◽  
Recovery Phase ◽  
Quadriceps Muscle ◽  
Voluntary Contraction ◽  
Second Phase ◽  
Contraction Force ◽  
Sprint Cycling

The aim of the study was to investigate the manifestation of potentiation and fatigue as well as the coexistence of these phenomena at different muscle lengths during a 24-hour period after a sprint cycling for 30 s. Material and methods. Twelve healthy untrained men (mean age 23.6±1.7 years) took part in the experiment. The contractility of quadriceps muscle was studied before (Initial) and 2, 5, 30, 60 min and 24 h after exercise via the electrically evoked contractions at 1, 15, 50 Hz and maximal voluntary contractions at short and long muscle length. Results. 1) In early, fast-recovery phase (within the first 5 min), muscle force evoked by electrical stimulation of 1, 15, 50 Hz was restored at short muscle length, conversely at long length (Initial vs. 5 min: 15 Hz and 50 Hz, both P<0.05), whereas maximal voluntary contraction force was still suppressed at both muscle lengths; 2) in the second phase (from 5 min to 30–60 min), muscle force decreased at low- and high-frequency stimulations and was more expressed at low-frequency stimulation and at short muscle length than that at long length, but the maximum voluntary contraction force recovered to initial; 3) in long-lasting phase (within 24 hours), 15 Hz force was still suppressed at both muscle lengths. Conclusion. A bimodal recovery of contractility of the quadriceps following sprint cycling for 30 s is determined by the concomitant complex interaction of mechanisms enhancing (potentiation) and suppressing (fatigue) contractile potential of the muscle.

Myogenic and Central Neurogenic Factors in Fatigue in Multiple Sclerosis

1996 ◽  
Vol 1 (4) ◽  
pp. 236-241 ◽  
Author(s):  
M Latash ◽  
E Kalugina ◽  
J Nicholas ◽  
C Orpett ◽  
D Stefoski ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Electrical Stimulation ◽  
Muscular Contraction ◽  
Quadriceps Muscle ◽  
Voluntary Contraction ◽  
Joint Torque ◽  
Subjective Feeling ◽  
Muscle Torque ◽  
Myogenic Factors ◽  
The Right

Short episodes of electrical stimulation were applied to the right quadriceps muscle of patients with multiple sclerosis (MS) and healthy subjects at different times during 60 sec sustained voluntary muscle contractions at 0 to 100% levels of maximal voluntarily generated joint torque. The amplitude of electrically induced increments of torque (ΔT) has been shown to depend upon both the level of muscular contraction and time from the beginning of the contraction. The dependence of ΔT upon the time from the beginning of contraction has been assumed to reflect muscle fatigue. Patients with MS demonstrated an apparent involvement of central neurogenic mechanisms in fatigue manifested as a drop in muscle torque during sustained contractions at 75 and 100% levels when electrical stimulation was able to induce considerable increments in muscle torque. These patients also demonstrated a dependence of ΔT upon the contraction level suggesting that they did not produce maximal voluntary contraction torque in the pre-trial. Fatigue in MS is due to central, neurogenic factors and does not seem to involve any myogenic factors such as might be related to secondary muscle changes due to the long-standing disorder. The subjective feeling of tiredness (‘fatigue’) may be related to a dissociation between central motor commands (‘effort’) and their mechanical consequences.

Force control of quadriceps muscle is bilaterally impaired in subacute stroke

2011 ◽  
Vol 111 (5) ◽  
pp. 1290-1295 ◽  
Author(s):  
John W. Chow ◽  
Dobrivoje S. Stokic
Keyword(s):  
Force Control ◽  
Maximum Voluntary Contraction ◽  
Quadriceps Muscle ◽  
Knee Extension ◽  
Voluntary Contraction ◽  
Force Variability ◽  
Stroke Patients ◽  
Subacute Stroke ◽  
Peak Knee ◽  
Isometric Knee Extension

We tested the hypothesis that force variability and error during maintenance of submaximal isometric knee extension are greater in subacute stroke patients than in controls and are related to motor impairments. Contralesional (more-affected) and ipsilesional (less-affected) legs of 33 stroke patients with sufficiently high motor abilities (62 ± 13 yr, 16 ± 2 days postinjury) and the dominant leg of 20 controls (62 ± 10 yr) were tested in sitting position. After peak knee extension torque [maximum voluntary contraction (MVC)] was established, subjects maintained 10, 20, 30, and 50% of MVC as steady and accurate as possible for 10 s by matching voluntary force to the target level displayed on a monitor. Coefficient of variation (CV) and root-mean-square error (RMSE) were used to quantify force variability and error, respectively. The MVC was significantly smaller in the more-affected than less-affected leg, and both were significantly lower than in controls. The CV was significantly larger in the more-affected than less-affected leg at 20 and 50% MVC, whereas both were significantly larger compared with controls across all force levels. Both more-affected and less-affected legs of patients showed significantly greater RMSE than controls at 30 and 50% MVC. The CV and RMSE were not related to the Fugl-Meyer motor score or to the Rivermead Mobility Index. The CV negatively correlated with MVC in controls but only in the less-affected leg of patients. It is concluded that isometric knee extension strength and force control are bilaterally impaired soon after stroke but more so in the more-affected leg. Future studies should examine possible mechanisms and the evolution of these changes.

Strength training reduces force fluctuations during anisometric contractions of the quadriceps femoris muscles in old adults

2004 ◽  
Vol 96 (4) ◽  
pp. 1530-1540 ◽  
Author(s):  
Brian L. Tracy ◽  
William C. Byrnes ◽  
Roger M. Enoka
Keyword(s):  
Strength Training ◽  
Angular Displacement ◽  
Quadriceps Femoris ◽  
Voluntary Contraction ◽  
Isometric Contractions ◽  
Heavy Load ◽  
Old Adults ◽  
Training Groups ◽  
Force Fluctuations ◽  
Quadriceps Femoris Muscles

The greater fluctuations in motor output that are often exhibited by old adults can be reduced with strength training. The purpose of the study was to determine the effect of strength and steadiness training by old adults on fluctuations in force and position during voluntary contractions with the quadriceps femoris muscle. Healthy old adults (65-80 yr) completed 16 wk of heavy-load (80% of maximum, n = 11) strength training, heavy-load steadiness training ( n = 6), or no training ( n = 9). Steadiness training required subjects to match the angular displacement about the knee joint to a constant-velocity template. The Heavy-Load group experienced a 5.5% increase in muscle volume, a 25% increase in maximal voluntary contraction force, and a 26% increase in the one-repetition (1-RM) load. The Heavy-Load Steady group experienced increases of 11.5, 31, and 36%, respectively. The maximal electromyogram signal of quadriceps femoris increased by 51% in the two training groups. The coefficient of variation (CV) for force during submaximal isometric contractions did not change with training for any group. Although both training groups also experienced a reduction in CV for force during anisometric contractions with a 50% 1-RM load, the standard deviation of position did not change with time for any group. The Heavy-Load Steady group also experienced a reduction in CV for force during the training contractions performed with the 80% 1-RM load. Thus strength training reduced the force fluctuations of the quadriceps femoris muscles during anisometric contractions but not during isometric contractions.

Age Differences in Eye Movements During Reading: Degenerative Problems or Compensatory Strategy?

2019 ◽  
Vol 24 (4) ◽  
pp. 297-311
Author(s):  
José David Moreno ◽  
José A. León ◽  
Lorena A. M. Arnal ◽  
Juan Botella
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Meta Analysis ◽  
Age Groups ◽  
Behavioral Changes ◽  
Aging Effects ◽  
Movement Data ◽  
Sentence Reading ◽  
The Difference ◽  
Eye Movements During Reading

Abstract. We report the results of a meta-analysis of 22 experiments comparing the eye movement data obtained from young ( Mage = 21 years) and old ( Mage = 73 years) readers. The data included six eye movement measures (mean gaze duration, mean fixation duration, total sentence reading time, mean number of fixations, mean number of regressions, and mean length of progressive saccade eye movements). Estimates were obtained of the typified mean difference, d, between the age groups in all six measures. The results showed positive combined effect size estimates in favor of the young adult group (between 0.54 and 3.66 in all measures), although the difference for the mean number of fixations was not significant. Young adults make in a systematic way, shorter gazes, fewer regressions, and shorter saccadic movements during reading than older adults, and they also read faster. The meta-analysis results confirm statistically the most common patterns observed in previous research; therefore, eye movements seem to be a useful tool to measure behavioral changes due to the aging process. Moreover, these results do not allow us to discard either of the two main hypotheses assessed for explaining the observed aging effects, namely neural degenerative problems and the adoption of compensatory strategies.

Cognitive Processing of Film Cuts Among 4- to 8-Year-Old Children

2012 ◽  
Vol 17 (4) ◽  
pp. 257-265 ◽  
Author(s):  
Carmen Munk ◽  
Günter Daniel Rey ◽  
Anna Katharina Diergarten ◽  
Gerhild Nieding ◽  
Wolfgang Schneider ◽  
...  
Keyword(s):  
Eye Movements ◽  
Cognitive Processing ◽  
Media Literacy ◽  
Age Groups ◽  
Reaction Times ◽  
Time Span ◽  
Short Film ◽  
Calculation Formula ◽  
Eye Tracker ◽  
Chronological Sequence

An eye tracker experiment investigated 4-, 6-, and 8-year old children’s cognitive processing of film cuts. Nine short film sequences with or without editing errors were presented to 79 children. Eye movements up to 400 ms after the targeted film cuts were measured and analyzed using a new calculation formula based on Manhattan Metrics. No age effects were found for jump cuts (i.e., small movement discontinuities in a film). However, disturbances resulting from reversed-angle shots (i.e., a switch of the left-right position of actors in successive shots) led to increased reaction times between 6- and 8-year old children, whereas children of all age groups had difficulties coping with narrative discontinuity (i.e., the canonical chronological sequence of film actions is disrupted). Furthermore, 4-year old children showed a greater number of overall eye movements than 6- and 8-year old children. This indicates that some viewing skills are developed between 4 and 6 years of age. The results of the study provide evidence of a crucial time span of knowledge acquisition for television-based media literacy between 4 and 8 years.

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