Validity of muscular fitness self-assessments in the ecofit smartphone application (Preprint)

BACKGROUND Mobile health apps that promote physical activity are being developed at a rapid rate. App-based interventions have the potential for wide reach and therefore, may be a useful tool in up-scaling physical activity interventions. In larger scale interventions, face-to-face assessments are less cost effective, and researchers often rely on surveys or built-in activity trackers to assess ongoing efficacy/effectiveness of outcomes. While there are valid means of assessing aerobic activity via smartphone apps, there is limited evidence of valid muscular fitness assessments that can be self-administered within mHealth. OBJECTIVE To evaluate the concurrent validity of upper and lower body muscular fitness that have been independently assessed by participants via the ecofit app, and face-to-face assessments conducted by a trained researcher. METHODS This study compared baseline data from the ecofit two-armed randomised controlled trial and self-assessed data collected via the ecofit smartphone app. As part of baseline assessment in a larger community-based physical activity intervention ‘ecofit’, participants undertook the validated 90-degree push-up and the 60-second sit-to-stand test face-to-face with a trained researcher. Those allocated to the intervention group received access to the ecofit app and were instructed to complete the self-assessed fitness tests within 14-days of receiving access to the app. To assess the concurrent validity, the self-assessed push-up and sit-to-stand tests were correlated using Spearman’s correlation coefficient against the research-assessed results. Bland-Altman plots were also used to allow visualisation of the differences between the self- and research-assessed tests. RESULTS Fifty-four participants completed at least one of the two muscular fitness self-assessments within 14-days of receiving the app, of these 24.1% and 100% completed the push-up and the sit-to-stand test respectively. The results found a strong significant correlation for the push-up test (0.83, p <.001) and a moderate significant correlation for the sit-to-stand test (0.63, p <.001). CONCLUSIONS This study provides support for the concurrent validity of self-reported upper and lower body muscular fitness assessments (i.e., the push-up and sit-to-stand tests) in mHealth. While these tests may be a feasible option for large scale physical activity interventions, more research is needed to determine the generalisability of these results. CLINICALTRIAL The ecofit trial is registered with the Australian and New Zealand Clinical Trial Registry (ANZCTR): ACTRN12619000868189.

The Importance of Cardiorespiratory vs. Muscular Fitness in Reducing the Odds of Hypertension in War Veterans: A Population-Based Study

Purpose: The purpose of the study was to examine separate and combined associations between cardiorespiratory fitness (CRF) and musculoskeletal fitness (MF) with hypertension. Methods: In this cross-sectional study, participants were 764 men and women aged 45–75 years, who were part of the Homeland War between 1990 to 1995 (33.5% women). CRF included the 2-min step test, while MF was consisted of push-ups in 30 s, chair-stands in 30 s and sit-ups in 30 s. The prevalence of hypertension was defined according to new American College of Cardiology and American Hearts Association Blood Pressure Guidelines for systolic and diastolic blood pressure of ≥130 mmHg and/or ≥80 mmHg. Results: In models adjusted for sex, age, fatness and fasting blood glucose, we found a graded inverse association between CRF and MF with hypertension. Less cardiorespiratory and muscular fit individuals were more likely to have hypertension. When CRF and MF were combined, individuals with high MF and low CRF, low MF and high CRF and low MF and CRF were 1.77, 2.15 and 7.09 more likely to have of hypertension. Conclusion: Both CRF and MF are associated with the prevalence of hypertension, while the magnitude of the associations between MF and hypertension was more pronounced.

Lower-Limb Electromyography Signal Analysis for the Bottom Group of Muscles Fitness Norm before and after Intensive Exercise

Muscular fitness is not only the ability of the body to adapt to work and the environment but also the operational ability of physical behavior. We speculated whether research could be conducted on the theory of muscular fitness and its qualitative/quantitative relationship based on muscular fitness and exercise physiology from the perspective of muscular endurance and muscular exploration. This study used standing long jumps as a standard metric for physical fitness to identify the bottom 20% groups. The experiment involved eight freshmen from the bottom 20% groups, and the pre-tests of the participants’ electromyography (EMG) signals under different exercise intensities were measured and after performing a set of intensive exercises for post-tests. The signal’ characteristics measured in time and frequency domains were analyzed to find the correlation between them and the participants’ muscular fitness. Weighted squats were chosen as the strength movements, which were separated into an exercise experiment and a force plate experiment. Both experiments included three different exercise intensities: 8 repetition maximum (RM), 18RM, and 28RM. The EMG signals were captured and analyzed in both time and the frequency domains. Finally, paired sample tests were performed to determine the difference of features under different exercise intensities. The comparison of readings before and after intensive exercises shows that, for the exercised experiment, a significant difference in the mean absolute (MAV), the variance of EMG (VAR), the root mean square value (RMS), and the average amplitude of change (AAC) was observed under 8RM. Under 18RM, MAV, VAR, and AAC showed a significant difference. In the force plate experiment, RMS, AAC, mean frequency (MNF), and median frequency (MDF) showed a statistically significant difference under the intensity of 18RM. As for intensity under 28RM, MAV, VAR, RMS, and AAC also showed significant difference.

The impact of physical fitness on resilience to modern life stress and the mediating role of general self-efficacy

Substantial evidence shows that physical activity and fitness play a protective role in the development of stress related disorders. However, the beneficial effects of fitness for resilience to modern life stress are not fully understood. Potentially protective effects may be attributed to enhanced resilience via underlying psychosocial mechanisms such as self-efficacy expectations. This study investigated whether physical activity and fitness contribute to prospectively measured resilience and examined the mediating effect of general self-efficacy. 431 initially healthy adults participated in fitness assessments as part of a longitudinal-prospective study, designed to identify mechanisms of resilience. Self-efficacy and habitual activity were assessed in parallel to cardiorespiratory and muscular fitness, which were determined by a submaximal step-test, hand strength and standing long jump test. Resilience was indexed by stressor reactivity: mental health problems in relation to reported life events and daily hassles, monitored quarterly for nine months. Hierarchical linear regression models and bootstrapped mediation analyses were applied. We could show that muscular and self-perceived fitness were positively associated with stress resilience. Extending this finding, the muscular fitness–resilience relationship was partly mediated by self-efficacy expectations. In this context, self-efficacy expectations may act as one underlying psychological mechanism, with complementary benefits for the promotion of mental health. While physical activity and cardiorespiratory fitness did not predict resilience prospectively, we found muscular and self-perceived fitness to be significant prognostic parameters for stress resilience. Although there is still more need to identify specific fitness parameters in light of stress resilience, our study underscores the general relevance of fitness for stress-related disorders prevention.

Standing Long Jump Performance in Youth with Visual Impairments: A Multidimensional Examination

Muscular fitness, an important marker of health in youth, includes explosive strength, which can be assessed using the standing long jump (SLJ). Little is known concerning the SLJ in populations with disabilities such as youth with visual impairments (VI) who trend with decreased health- and performance-related outcomes. The purposes of this study were to investigate multidimensional SLJ performance outcomes in youth with VI (i.e., descriptives and percentages of occurrence) and to explore associations among such variables and known factors of interest (e.g., age) using robust linear bivariate regressions. This study was a secondary analysis from data collected in 2018 (N = 61, Mage = 12.98 years, SD = 2.21). SLJ performance was investigated using a multidimensional focus (e.g., distance, Test of Gross Motor Development-3 horizontal jump, landing developmental sequences, landing joint displacement, and stabilization after landing). In general, SLJ performance was substandard in youth with VI. Most SLJ assessment scores were predictive of other SLJ assessment scores. Few hypothesized variables of interest (e.g., multimorbidity) were predictive of SLJ performance. Youth with VI who match the characteristics of the current sample may have decreased explosive strength/muscular fitness and, worryingly, their SLJ performance may not be influenced by expected factors (e.g., age). Implications and explanations for these results are discussed.