Related Experiment Video
Updated: Jan 30, 2026
The Muscle Cuff Regenerative Peripheral Nerve Interface for the Amplification of Intact Peripheral Nerve Signals
Published on: January 13, 2022
Age related changes of the motor excitabilities and central and peripheral muscle strength
Yu-Fen Chuang1, Chih-Chung Chen1, Miao-Ju Hsu2
1School of Physical Therapy and Graduate Institute of Rehabilitation Science, College of Medicine, and Healthy Aging Research Center, Chang Gung University, Taoyuan, Taiwan; Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan.
Introduction:
The purpose was to investigate the age effects on central versus peripheral sources of strength, fatigue, and central neural excitabilities.
Methods:
42 healthy subjects were recruited as young group (23.73 ± 2.15 years; n = 26) and middle-aged group (57.25 ± 4.57 years; n = 16). Maximum voluntary contraction force (MVC), voluntary activation level (VA), and twitch force of quadriceps were evaluated to represent general, central, and peripheral strengths. Central and peripheral fatigue indexes were evaluated using femoral nerve electrical stimulation. Cortical excitabilities were evaluated using transcranial magnetic stimulation (TMS).
Results:
The middle-aged group had lower MVC and twitch force of quadriceps, but not VA, than young group. No between group differences were found in fatigue indexes. The cortical excitability in middle-aged group was different from young group in paired TMS with inter-stimulus interval of 7 ms.
Conclusion:
The age-related strength loss at early stage was primarily caused by peripheral muscular strength. The deviation of central neural excitability can be detected but the activation level was not impaired in middle-age adults.
More Related Videos
Related Concept Videos
01:09Peripherally and Centrally Acting Muscle Relaxants: A Comparison
Centrally acting muscle relaxants can be further divided into spasmolytic and antispasmodic drugs. Spasmolytic...
01:20Excitation-Contraction Coupling in Skeletal Muscles
When an action...
01:24Centrally Acting Muscle Relaxants: Therapeutic Uses
Centrally acting drugs are classified into spasmolytic and antispasmodic drugs. Spasmolytic drugs such as baclofen, diazepam, and tizanidine inhibit spinal motor neurons and decrease muscle tone. Spasmolytic drugs are administered for severe and chronic spasms due to multiple sclerosis, cerebral palsy, stroke, and spinal cord and muscle injuries. However,...
03:05Acid Strength and Molecular Structure
In the absence of any leveling effect, the acid strength of binary compounds of hydrogen with nonmetals (A) increases as the H-A bond strength decreases down a group in the periodic table. For group 17, the order of increasing acidity is HF < HCl < HBr < HI. Likewise, for group 16, the order of increasing acid strength is H2O < H2S < H2Se < H2Te. Across a row in the periodic table, the acid strength of binary hydrogen compounds increases with increasing...
01:25The Central Dogma
01:20Strength of Cement
For compressive strength tests, ASTM C 109-05 standards prescribe a cement-sand mix ratio of 1:2.75 and a water/cement ratio of 0.485 for making 2-inch cubes. These cubes are mixed, cast, and cured in saturated lime water at 23°C until testing. Flexural strength testing, outlined in...