Mechanisms underpinning diurnal variation in human muscle performance
Research type
Research Study
Full title
Mechanisms underpinning diurnal variation in human muscle performance
IRAS ID
149237
Contact name
Jatin G Burniston
Contact email
Research summary
Muscle weakness and loss of muscle mass is associated with a greater risk of falls in the elderly, which may lead to hospitalization and loss of independence. Approximately 1 in 3 adults aged over 65 falls each year, and twice the number of falls occur in the morning, when muscle strength is at its lowest, compared to in the afternoon/ early evening.
Diurnal variations in muscle force and sports performance in young healthy individuals is also widely reported but the mechanisms underpinning this phenomenon are not yet understood. Muscle force production is poorest between the hours of 06.00 - 08.00 in the morning and greatest between 16.00 - 18.00 in the afternoon. The magnitude of variation is approximately 10 %, which is highly significant given the rate of decline in muscle force production is estimated at ~1.3 % per year in individuals over 60 years of age.
Based on recent preliminary studies we know the component of muscle performance that shows the greatest magnitude of diurnal variation is the rate of force development during the initial milliseconds of a contraction. Moreover, the difference in muscle output is not due to differences in core body temperature or other external factors. The proposed work will investigate whether modifications to the contractile apparatus occur that might explain the differences in muscle function.
Diurnal differences in the modification status of contractile proteins will be investigated using a balanced cross-over design. Ten healthy young males with experience of strength training will be randomly assigned to 2 groups: Group 1 = ‘morning-evening’ whereas Group 2 = ‘evening-morning’. Muscle performance will be measured prior to a biopsy being taken from the thigh muscle. Each participant will provide a total of 2 biopsy samples, which will be collected on separated days within a 2-week period.REC name
West Midlands - Black Country Research Ethics Committee
REC reference
14/WM/0065
Date of REC Opinion
17 Mar 2014
REC opinion
Further Information Favourable Opinion