Different periodization models have been widely used to improve maximum and rapid force in aging adults. However, it is unclear if some specific model can influence the remarkable heterogeneity of responsiveness to rapid torque improvements following resistance training.
Compare the effects of mixed session periodization (MSP) and traditional (TP) models on neuromuscular performance and individual responsiveness in aging adults.
Twenty-two aging men and women (64.6 ± 5.2 years old; 1.68 ± 0.1 m; 77.8 ± 16.0 kg) completed the intervention period. They were assigned into MSP (n = 11) or TP (n = 11) resistance training for lower limbs. The outcome measures normalized dynamic leg press (5-RM:BM), absolute and normalized knee isometric peak torque (PT and PT:BM) and rate of torque development, and impulse were assessed at baseline and after three blocks of a 9-wk resistance training (3 sessions per week). Thigh leg lean mass was assessed by dual-energy x-ray absorptiometry at baseline and after the intervention.
Similar increases were observed for 5-RM:BM (MSP: 28.8% ± 13.5% and TP: 26.4% ± 7.6%, P < 0.001), PT (MSP: 223.7 ± 50.7 N·m and TP: 189.9 ± 58.6 N·m, P < 0.001), but it was not observed for PT:BM (MSP: 16.4% ± 16.5% and TP: 4.7% ± 9.2%, P > 0.05). Absolute and normalized RTD remained unchanged throughout intervention (P > 0.05), but both groups improved impulse (MSP: 22.1% ± 25.7% and TP: 12.6% ± 45.2%, P < 0.001). Only MSP responders (n = 5) presented significant time effect for absolute RTD (P < 0.05) and impulse (P < 0.05).
Although both periodization protocols increased 5-RM:BM and PT, it was not interchangeable through improvements in RTD even adopting power training session. Furthermore, these results suggest a great inter-individual variability following different periodization models for aging people.
There has been considerable innovation and advancement in the field of exercise and physical activity (PA). In regards to the battle against chronic non-communicable disease, however, we believe the model of PA that would prove most salutary is one closely mimicking that of our hunter-gatherer ancestors. For the purpose of longevity, the human body and our genetic makeup have been evolutionarily adapted to respond best to moderate amounts of high-intensity interval training, in conjunction with high amounts of low intensity exercise. Moreover, to optimize resiliency and cardiorespiratory fitness, a hunter-gatherer fitness regimen must include cross training targeted at flexibility, balance and strength. Though not commonly understood, the health benefits from exercise comprise a reverse J-curve. The endurance athletes residing on the furthest reaches of the PA spectrum appear to lose a substantial portion of the exercise-related longevity and cardiovascular benefits due to cardiac overuse injury. Conversely, there is an emerging body of evidence suggesting leisure time exercise done with peers in a natural environment is significantly superior to that training done in solitude. This idea of the “power of play” lends support to the ancestral model of PA whereby humans are evolutionary adapted to be highly social, outdoor creatures capable of a diverse range of PA at varying intensities.
It is known that COVID-19 spread mainly from person-to-person through respiratory droplets produced when an infected person coughs or sneezes, and as a result certain ideas about contagious of COVID-19 have been spread. One of them is the widespread belief that close runners, owing to the stronger exhalation, can be more prone to be infected with COVID-19 because the collision with the suspended respiratory droplets should the runner in front be infected. However, because of the low Stokes number this idea cannot be generalized without carefully thought and in fact can be put into question. Utilizing the raindrop collisional model and with the help of computational fluid dynamics (CFD), it is shown that the probability of collision with respiratory droplets is not always increasing with the approaching velocity of the runner but rather there is a maximum velocity threshold at which the efficiency of collision drops.
To determine the relationship between metabolic fitness test scores and performance in police occupational tasks.
Retrospective data from 106 law enforcement officers who completed two metabolic fitness assessments [anaerobic: a 20-m (10-m and 20-m splits) sprint, aerobic: 20 m Multi-Stage Fitness Test (20 m-MSFT)] and three routine occupational tasks [1.22 m Fence jump (FJ), 8.5 m Victim Drag (VD with 102.3 kg) and “Get-up” (GU)] were collected. A Person’s correlation coefficient and a standard multiple regression were used to assess the relationship between and predictive ability of, respectively, the fitness tests scores and performance on occupational tasks.
There was a significant positive correlation between the 10-m sprint scores and FJ (r = 0.524, P < 0.001), VD (r = 0.528, P < 0.001) and GU (r = 0.486, P < 0.001). Similarly, the 20-m sprint scores were significantly and moderately correlated with FJ (r = 0.573, P < 0.001), VD (r = 0.603, P < 0.001) and GU (r = 0.533, P < 0.001). These anaerobic tests’ scores predicted approximately 40% of the performance in the occupational tasks analysed. The MSFT fitness assessment had a small, albeit significant negative correlation with the three tasks: FJ (r = − 0.360, P < 0.001), VD (r = − 0.266, P = 0.012) and GU (r = − 0.375, P < 0.001).
High levels of metabolic fitness correlated with faster performance in police officer occupational tasks, particularly ones of an anaerobic nature (i.e. the maximal sprint tests). In addition to typical aerobic fitness conditioning, anaerobic fitness conditioning could be vital for optimal performance in physically demanding tasks required of police officer.
To compare physical activity and sedentary behavior between four commonly used subjective and objective measures: the 7-day Physical Activity Recall (7DPAR), International Physical Activity Questionnaire (IPAQ), pedometer, and accelerometer.
A total of 130 college students completed four measures for the same 7 days. Body composition was measured using a bioelectric impedance analyzer. Wilcoxon signed rank tests and Spearman correlations were performed to compare estimates between activity measures. The Spearman correlations between different activity measures were further examined separately for the higher and the lower body fat groups.
Compared with accelerometer-derived data, both the 7DPAR and the IPAQ overestimated light physical activity (P < 0.001) while underestimated sedentary behavior (P < 0.001). Across comparisons, the highest correlation was found between accelerometers and pedometers on steps/day (r = 0.72, P < 0.001). The 7DPAR and the IPAQ were correlated with each other for all physical activity variables and sedentary behavior (r = 0.37–0.45). There were low correlations (r = 0.20–0.47) between the 7DPAR, the IPAQ, and accelerometers in sedentary behavior, light physical activity, and vigorous physical activity. Higher correlations between different activity modalities were observed among individuals with lower body fat (r = 0.41–0.80) than among those with higher body fat (r = 0.31–0.65).
The 7DPAR and the IPAQ yielded comparable estimation of moderate physical activity relative to accelerometers. There were significant differences in sedentary time across activity measures. Body compositions should be considered when comparing the estimates of activity levels between subjective and objective instruments.
The purpose of the present study was to examine the day-to-day consistency and inter-subject variability of composite and individual, neuromuscular and torque patterns of responses as a result of a fatiguing bout of maximal, bilateral, isokinetic leg extension muscle actions.
Ten men (Mean ± SD = 21.6 ± 2.5 years) completed two testing visits consisting of pretest and posttest maximal voluntary isometric contractions (MVIC) as well as 25 maximal, bilateral, isokinetic (180°/s), leg extension muscle actions. Electromyographic (EMG) and mechanomyographic (MMG) signals were collected from the vastus lateralis and normalized to the MVIC. Performance fatigability was defined as the percent decline in torque between the average of repetitions 1, 2, and 3 and repetitions 23, 24, and 25. Polynomial regression was used to examine the individual and composite relationships between EMG amplitude (AMP), EMG mean power frequency (MPF), MMG AMP, MMG MPF, and torque versus repetitions.
There was no significant difference (d = 0.80; P = 0.17) in the performance fatigability between Day 1 (19.3% ± 7.1%) and Day 2 (26.9% ± 11.3%). Polynomial regression indicated substantial inter-subject variability, but high day-to-day consistency.
The composite EMG AMP, MMG AMP, and MMG MPF patterns of responses demonstrated consistency across days. The composite EMG MPF patterns of responses, however, were not consistent between Day 1 and Day 2. In addition, based on the high inter-subject variability, future studies should present both composite patterns of neuromuscular responses and the patterns of responses on a subject-by-subject basis to make inferences regarding fatigue-induced changes in motor unit activation strategies.