***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Summary Methods that objective ly assess the muscle fibre-type arrangement may improve the detection of fibre-type grouping , a diagnostic sign of a denervation and reinnervation process . To distinguish between a diseased and a normal muscle , there is a need for quantitative data on the fibre-type arrangement in healthy human muscles at different ages . In this study , cross-sections were prepared of whole autopsied vastus lateralis muscle  from 24 previously physically healthy men , aged 15 to 83 years . The arrangements of type 1 and type 2 fibres were assessed in terms of the number of enclosed fibres in individual fascicles throughout each muscle . Recent improvements to the enclosed fibre method were used to define measures of r and omness which facilitated the combination of several sample areas and the quantification of the fibre-type arrangements . Segregation was typical for young muscles , r and omness was most common between 30 and 50 years of age , while some fibre-type grouping was considered “ normal ” in old muscles . The arrangements of type 1 and type 2 fibres were quantitatively similar , irrespective of the age of the individual . The results imply that the fibre population changes considerably during a lifetime , and that it undergoes a continuous denervation and reinnervation process with normal ageing . Because of its importance , age should be accommo date d in the analysis of a muscle sample , irrespective of the statistical model and method used The present study was design ed to examine the finger-pinch force control , digit force sharing and digit coupling relations of 13 young and 14 older adults . Subjects performed four isometric tri-digit finger-pinch force production conditions reflecting all combinations of mean force level ( 20 and 40 % MVC ) and target shape ( constant and sinusoidal ) . Older adults had significantly reduced force control , as indicated by their greater levels of absolute and relative force variability and targeting error than young adults . The age-related loss of relative force control was more pronounced at low ( 20 % MVC ) than high ( 40 % MVC ) forces , and to a lesser extent , in sinusoidal than constant force conditions . Older adults had significantly greater peak and proportional power below 1.5 Hz than young adults , with this especially pronounced in constant force conditions . Digit force sharing results indicated that the index finger ’s contribution to total force was increased and the middle finger ’s contribution reduced in older than young adults . The results of the cross-correlation analyses revealed that older subjects had a significantly reduced level of coupling between the middle finger and the target force , thumb force and EMG signals , with longer time lags in comparison to young adults . These differences in force sharing and middle finger force coupling were more pronounced in sinusoidal than constant force conditions . Overall , these results suggest that the older adults ’ reduced force control reflected age-related differences in the sharing and coupling of the finger forces . The results also highlighted that tasks of this nature display a degree of task-dependency , with these overall differences in digit force output and coupling not consistently observed across all force conditions The purpose of this study was to investigate the effects of aging and the role of augmented visual information in the acquisition of a new bimanual coordination pattern , namely a 90 degrees relative phase pattern . In a pilot study , younger and older adults received augmented visual feedback in the form of a real-time orthogonal display of both limb movements after every fifth trial . Younger adults acquired this task over three days of practice and retained the task well over periods of one week and one month of no practice while the older adults showed no improvement at all on the task . It was hypothesized that the amount of augmented information was not sufficient for the older adults to overcome the strong tendency to perform natural , intrinsically stable coordination patterns , which consequently prevented them from learning the task . The present study evaluated the age-related role of augmented visual feedback for learning the new pattern . Participants were r and omly assigned within age groups to receive either concurrent or terminal visual feedback after every trial in acquisition . In contrast to the pilot study , all of the older adults learned the pattern , although not to the same level as the younger adults . Both younger and older adults benefitted from concurrent visual feedback , but the older adults gained more from the concurrent feedback than the younger adults , relative to terminal feedback conditions . The results suggest that when learning bimanual coordination patterns , older adults are more sensitive to the structure of the practice conditions , particularly the availability of concurrent visual information . This greater sensitivity to the learning environment may reflect a diminished capacity for inhibitory control and a decreased ability to focus attention on the salient aspects of learning the task 
    Output:
    
These findings indicate that older adults displayed reduced accuracy , greater variability , and longer execution time when executing bimanual movements .
Conclusion : These meta‐analytic findings revealed that aging impairs bimanual movement performance .
HighlightsPrevious bimanual movements and aging studies report conflicting results .Current meta‐ analysis revealed impaired bimanual movements in older adults .
Older adults showed less accuracy , more variability , and longer movement time