Effect of acceleration on the rate of power development and neural activity of the leg extensors across the adult life span
- 11 Downloads
The rate of power development (RPD) represents the capacity to rapidly generate power during a dynamic muscle contraction. As RPD is highly susceptible to aging, its decline can have important functional consequences. However, the effect of age on RPD in response to rapid changes in movement velocity (cfr. fall incidence) is not yet clear. Therefore, the present study aimed to examine the effect of age on RPD and neural drive in response to different accelerations.
Three maximal isokinetic leg extensor tests at 540°/s with different initial acceleration phases at 3200, 5700 and 7200°/s2 were performed. RPD, which is the slope of the power-time curve during the acceleration phase, was calculated for 83 subjects aged between 20 and 69 years. Mean electromyography signal amplitude was determined for rectus femoris (RF), vastus lateralis (VL) and biceps femoris muscles.
The average annual age-related decline rate of RPD at highest acceleration was − 2.93% and was − 1.52% and − 1.82% higher compared to lower acceleration rates (p < 0.001). This deficit can probably be explained by an age-related impairment in neural drive during the first 75 ms of the acceleration phase, as evidenced by a reduced RF and VL neuromuscular activity of − 0.30% and − 0.36% at highest versus lowest acceleration (p < 0.05).
These findings highlight the inability of aged individuals to quickly respond to abrupt changes in movement velocity, which requires more focus in training and prevention programs.
KeywordsSarcopenia Aging Fall prevention Explosive power
Mean EMG amplitude
Rate of power development
SVD conceived of the study, participated in the design and coordination of the study, performed the measurements and analysis, interpreted the data and wrote the manuscript; EVR participated in the design of the study, interpretation of the data and writing of the manuscript; BVW participated in the design of the study and writing of the manuscript; CD conceived of the study, participated in the design of the study and interpretation of the data and approved the final manuscript.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no competing interest.
- Kuznetsova A, Brockhoff PB, Christensen RHB (2016) lmerTest: tests in linear mixed effects models. R package version 2.0-33. https://CRAN.R-project.org/package=lmerTest. Accessed Feb 2018
- Milat AJ, Watson WL, Monger C, Barr M, Giffin M, Reid M (2011) Prevalence, circumstances and consequences of falls among community-dwelling older people: results of the 2009 NSW Falls Prevention Baseline Survey. N S W Public Health Bull 22:43–48. https://doi.org/10.1071/NB10065 CrossRefPubMedGoogle Scholar
- R Core Team (2017) R: a language and environment for statistical computing. R Foundation for Statistical Computing, ViennaGoogle Scholar
- Tillin NA, Pain MT, H G, Folland GM,TB J (2013b) The human capacity to produce explosive torque is influenced by contraction type and acceleration. Paper presented at the XXIV congress of the international society of biomechanics, Natal, Brazili, 4th–9th AugustGoogle Scholar