Background: Transcranial magnetic stimulation (TMS) is a non-invasive technique that can be used to evaluate cortical function and corticospinal pathway in normal and pathological aging. Yet, the metrologic properties of TMS-related measurements is still limited in the aging population.Objectives: The aim of this cross-sectional study was to document the reliability and smallest detectable change of TMS measurements among community-dwelling seniors. A secondary objective was to test if TMS measurements differ between elders based on lifestyle, medical and socio-demographic factors.Methods: Motor evoked potentials (MEPs) elicited by single-pulse TMS were recorded in the first dorsal interosseous (FDI) in 26 elderly individuals (mean age = 70 ± 3.8 years). Resting motor threshold (rMT), MEP amplitudes and contralateral silent period (cSP) were measured on two separate occasions (1-week interval), and the standard error of the measurement (SEMeas), intraclass correlation coefficient (ICC), and smallest detectable change in an individual (SDCindv) were calculated. Lifestyle, medical and socio-demographic factors were collected using questionnaires. TMS-related outcomes were compared using independent sample t-test based on the presence of chronic health diseases, chronic medication intake, obesity, history of smoking, physical activity levels, gender, and level of education.Results: rMT and cSP measures were the most reliable outcomes, with the lowest SEMeas and highest ICCs, whereas MEP amplitude-related measures were less reliable. SDCindv levels were generally high, even for rMT (7.29 %MSO) and cSP (43.16–50.84 ms) measures. Although not systematically significant, results pointed toward a higher corticospinal excitability in elderly individuals who were regularly active, who had no chronic medical conditions and who did not take any medication.Conclusion: Even though SDCindv levels were relatively high, these results show that rMT and cSP are the most reliable outcomes to investigate age-related changes in the corticomotor system and suggest that the influence of factors such as lifestyle habits and medications on TMS measures should be investigated further.

BackgroundBecause of their importance in core stability, training the deep abdominal muscles, fascial structures and particularly the transversus abdominis, is a key component of many sport and physical therapy programs. However, there are gaps in knowledge about age-related changes in the structure and activation capacity of these muscles.

Forty participants were randomized into 2 groups (RUSI or PBU). The intervention included a training session involving 15 TrA contractions held for 10 seconds with the corresponding feedback device. The dependent variable, TrA thickness (a muscle activation indicator), was measured using ultrasound images before and after the intervention in a supine and standing position. Nonparametric analyses were used for inter-and intragroup comparisons. Results and Discussion:The results showed no between-group differences in TrA activation ratio (AR) in the supine or standing position (supine AR: TrA RUSI thickness change P = .53 vs PBU thickness change P = .73, comparison between groups P = .51; standing AR: TrA RUSI thickness change P = .003 vs PBU thickness change P = .10; comparison between groups P = .61). However, the change in TrA thickness compared to the other abdominal wall muscles in a standing position was significantly less post-intervention for the RUSI group only (RUSI P = .006 vs PBU P = .72). Both groups remained similar post-intervention for this outcome (P = .20). Conclusions: Neither the RUSI nor the PBU seems to have the desired effect on the activation of TrA in asymptomatic older adults.