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1
THE CORTEX IS A CRITICAL DETERMINANT OF MUSCLE STRENGTH/WEAKNESS
Clark BC1, Mahato NK2, Nakazawa M3, Law TD4, Thomas JS5.
DESIGN
– Group 1: 4 wks of wrist-hand immobilization to induce weakness
– Group 2: 4 wks of immobilization, but they also performed mental imagery of strong muscle contractions 5 days/wk
– Group 3: control group
– Mental imagery has been shown to activate several cortical areas that are involved with actual motor behaviors
– Before, immediately after, and 1 wk following immobilization, we measured wrist flexor strength, voluntary activation (VA), and the cortical silent period (SP)
RESULTS
(1) Immobilization decreased strength 45.1 ± 5.0%, impaired VA 23.2 ± 5.8%, and prolonged the SP 13.5 ± 2.6%
(2) Mental imagery training, however, reduced loss of strength and VA by ∼50% (23.8 ± 5.6% and 12.9 ± 3.2% reductions, respectively) and eliminated prolongation of the SP (4.8 ± 2.8% reduction)
(3) Significant associations were observed between the changes in muscle strength and VA and SP
CONCLUSIONS
(1) These findings suggest neurological mechanisms, most likely at the cortical level, contribute significantly to disuse-induced weakness
(2) Regular activation of the cortical regions via imagery reduces weakness and VA by maintaining normal levels of inhibition
1
HIPPOCAMPAL AND CEREBRAL BLOOD FLOW AFTER EXERCISE CESSATION IN MASTER ATHLETES
METHOD
– Endurance exercise training improves cerebrovascular health and has neurotrophic effects within the hippocampus
– 12 master athletes (age ≥ 50 years) with long-term endurance training histories (≥15 years)
– cease all training and vigorous physical activity for 10 consecutive days
RESULTS
– Resting Cerebral Blood Flow significantly decreased in eight gray matter brain regions
LIGHT PHYSICAL ACTIVITY IS POSITIVELY ASSOCIATED WITH COGNITIVE PERFORMANCE IN OLDER ADULTS
METHOD
– 188 community-dwelling older adults (53.7% female; 63.98±7.3 years)
– 7 day physical activity behaviour monitoring
CONCLUSIONS
– Light physical activity is associated with higher executive functioning in community-dwelling older adults
– This strengthens the evidence supporting exercise as a neuroprotective agent
ASSOCIATION BETWEEN LIFETIME PHYSICAL ACTIVITY & COGNITIVE FUNCTIONING IN MIDDLE AGED AND OLDER ADULTS
– Gill SJ, et al
METHODS
– 226 (52.2% female) community dwelling middle-aged and older adults (66.5±6.4 yrs) in the Brain in Motion Study
– Completed the Lifetime Total Physical Activity Questionnaire and underwent neuropsychological and cerebrovascular blood flow testing
CONCLUSION
– Significant associations between higher levels of PA (i.e., total lifetime, recreational, vigorous PA, and past year) and better cognitive function in later life
12 WK PHYSICAL AND COGNITIVE EXERCISE PROGRAM CAN IMPROVE COGNITIVE FUNCTION AND NEURAL EFFICIENCY IN OLDER ADULTS
Nishiguchi S Yamada M Tanigawa T Sekiyama K Kawagoe T Suzuki M, et al.
PARTICIPANTS
– Community-dwelling older adults (N = 48) were randomized into an exercise group (n = 24) and a control group (n = 24).
INTERVENTION
– Exercise group received a weekly dual task-based multimodal exercise class in combination with pedometer-based daily walking exercise during the 12-wk intervention phase
– Control group did not receive any intervention and were instructed to spend their time as usual during the intervention phase
CONCLUSION
– The program improved the efficiency of brain activation which is associated with improvements in memory and executive function