Motor variability during sustained contractions increases with cognitive demand in older adults
To expose cortical involvement in age-related changes in motor performance, we compared steadiness (force fluctuations) and fatigability of submaximal isometric contractions with the ankle dorsiflexor muscles in older and young adults and with varying levels of cognitive demand imposed. Sixteen you...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2014-05-01
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| Series: | Frontiers in Aging Neuroscience |
| Subjects: | |
| Online Access: | http://journal.frontiersin.org/Journal/10.3389/fnagi.2014.00097/full |
| _version_ | 1811322852004069376 |
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| author | Marnie L Vanden Noven Hugo M Pereira Tejin eYoon Alyssa eStevens Kristy A Nielson Sandra K Hunter |
| author_facet | Marnie L Vanden Noven Hugo M Pereira Tejin eYoon Alyssa eStevens Kristy A Nielson Sandra K Hunter |
| author_sort | Marnie L Vanden Noven |
| collection | DOAJ |
| description | To expose cortical involvement in age-related changes in motor performance, we compared steadiness (force fluctuations) and fatigability of submaximal isometric contractions with the ankle dorsiflexor muscles in older and young adults and with varying levels of cognitive demand imposed. Sixteen young (20 ± 2 yr: 8 men, 8 women) and 17 older adults (69 ±4 yr: 9 men, 8 women) attended three sessions and performed a 40 s isometric contraction at 5% maximal voluntary contraction (MVC) force followed by an isometric contraction at 30% MVC until task failure. The cognitive demand required during the submaximal contractions in each session differed as follows: 1) high-cognitive demand session where difficult mental math was imposed (counting backward by 13 from a 4-digit number); 2) low-cognitive demand session which involved simple mental math (counting backward by one); and 3) control session with no mental math. Anxiety was elevated during the high-cognitive demand session compared with other sessions for both age groups but more so for the older adults than young adults (p<0.05). Older adults had larger force fluctuations than young adults during: 1) the 5% MVC task as cognitive demand increased (p=0.007), and 2) the fatiguing contraction for all sessions (p=0.002). Time to task failure did not differ between sessions or age groups (p>0.05), but the variability between sessions (standard deviation [SD] of 3 sessions) was greater for older adults than young (2.02 ± 1.05 min vs. 1.25 ± 0.51 min, P<0.05). Thus, variability in lower limb motor performance for low and moderate force isometric tasks increased with age and was exacerbated when cognitive demand was imposed, and may be related to modulation of synergist and antagonist muscles and an altered neural strategy with age originating from central sources. These data have significant implications for cognitively demanding low-force motor tasks that are relevant to functional and ergonomic in an aging workforce. |
| first_indexed | 2024-04-13T13:43:26Z |
| format | Article |
| id | doaj.art-86487f82be4141c5a234c25ad3bf3c0f |
| institution | Directory Open Access Journal |
| issn | 1663-4365 |
| language | English |
| last_indexed | 2024-04-13T13:43:26Z |
| publishDate | 2014-05-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Aging Neuroscience |
| spelling | doaj.art-86487f82be4141c5a234c25ad3bf3c0f2022-12-22T02:44:34ZengFrontiers Media S.A.Frontiers in Aging Neuroscience1663-43652014-05-01610.3389/fnagi.2014.0009788673Motor variability during sustained contractions increases with cognitive demand in older adultsMarnie L Vanden Noven0Hugo M Pereira1Tejin eYoon2Alyssa eStevens3Kristy A Nielson4Sandra K Hunter5Marquette UniversityMarquette UniversityMichigan Technological UniversityMarquette UniversityMarquette UniversityMarquette UniversityTo expose cortical involvement in age-related changes in motor performance, we compared steadiness (force fluctuations) and fatigability of submaximal isometric contractions with the ankle dorsiflexor muscles in older and young adults and with varying levels of cognitive demand imposed. Sixteen young (20 ± 2 yr: 8 men, 8 women) and 17 older adults (69 ±4 yr: 9 men, 8 women) attended three sessions and performed a 40 s isometric contraction at 5% maximal voluntary contraction (MVC) force followed by an isometric contraction at 30% MVC until task failure. The cognitive demand required during the submaximal contractions in each session differed as follows: 1) high-cognitive demand session where difficult mental math was imposed (counting backward by 13 from a 4-digit number); 2) low-cognitive demand session which involved simple mental math (counting backward by one); and 3) control session with no mental math. Anxiety was elevated during the high-cognitive demand session compared with other sessions for both age groups but more so for the older adults than young adults (p<0.05). Older adults had larger force fluctuations than young adults during: 1) the 5% MVC task as cognitive demand increased (p=0.007), and 2) the fatiguing contraction for all sessions (p=0.002). Time to task failure did not differ between sessions or age groups (p>0.05), but the variability between sessions (standard deviation [SD] of 3 sessions) was greater for older adults than young (2.02 ± 1.05 min vs. 1.25 ± 0.51 min, P<0.05). Thus, variability in lower limb motor performance for low and moderate force isometric tasks increased with age and was exacerbated when cognitive demand was imposed, and may be related to modulation of synergist and antagonist muscles and an altered neural strategy with age originating from central sources. These data have significant implications for cognitively demanding low-force motor tasks that are relevant to functional and ergonomic in an aging workforce.http://journal.frontiersin.org/Journal/10.3389/fnagi.2014.00097/fullAgingArousalIsometric ContractionMuscle FatigueDual taskgender |
| spellingShingle | Marnie L Vanden Noven Hugo M Pereira Tejin eYoon Alyssa eStevens Kristy A Nielson Sandra K Hunter Motor variability during sustained contractions increases with cognitive demand in older adults Frontiers in Aging Neuroscience Aging Arousal Isometric Contraction Muscle Fatigue Dual task gender |
| title | Motor variability during sustained contractions increases with cognitive demand in older adults |
| title_full | Motor variability during sustained contractions increases with cognitive demand in older adults |
| title_fullStr | Motor variability during sustained contractions increases with cognitive demand in older adults |
| title_full_unstemmed | Motor variability during sustained contractions increases with cognitive demand in older adults |
| title_short | Motor variability during sustained contractions increases with cognitive demand in older adults |
| title_sort | motor variability during sustained contractions increases with cognitive demand in older adults |
| topic | Aging Arousal Isometric Contraction Muscle Fatigue Dual task gender |
| url | http://journal.frontiersin.org/Journal/10.3389/fnagi.2014.00097/full |
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