Perceptions of fatigue and neuromuscular measures of performance fatigability during prolonged low-intensity elbow flexions

The effects of different fatigue types on action anticipation and physical performance in high-level volleyball players

This study examined the effects of different fatigue types on action anticipation and physical performance in high-level volleyball players. Twenty-four participants underwent four counterbalanced conditions: 60-min cycling at 60% peak power output, 60-min Stroop task, 60-min cycling at 60% peak power output with Stroop task and 60-min neutral documentary to induce physical fatigue (PF), mental fatigue (MF), dual fatigue (DF) and control group (CG), respectively. Action anticipation (anticipation test and visual search test) and physical performance (countermovement jump, T-test, and spike test) were conducted at baseline, immediately after (Post1), and after 10-min rest (Post2). DF and PF led to significantly lower jump height, T-test completion time, and spiking speed at Post1 and Post2 compared with CG and MF. Compared with PF, DF led to a significant decline in jumping, agility, and spiking performance at Post1 and decreased jumping performance at Post2. MF significantly decreased the reaction time of anticipation test at Post1 compared with CG. Reaction times of visual search test were significantly lower in DF and MF at Post2 compared with CG. It is suggested that PF decreased physical performance, and this is exacerbated in DF. Anticipation performance was affected by MF but not by DF and PF.

Perceived Factors That Contributed to Task Termination during Fatiguing Tasks Anchored to Perceptual Intensities

This study examined the effects of sustained, isometric forearm flexion tasks anchored to ratings of perceived exertion of 2 (RPE2FT) and 8 (RPE8FT) on the patterns of fatigue-induced changes in torque and neuromuscular responses, time to task failure (TTF), performance fatigability (% decline in maximal voluntary isometric contraction [MVIC]), and perceived factors that contributed to task termination. Twelve men (mean ± SD: age = 20.9 ± 2.2 yrs) performed MVICs before and after the tasks and completed post-test questionnaires (PTQ). Data were analyzed using polynomial regression analyses, dependent t-tests, Spearman's rank order correlations, and Wilcoxon signed rank tests. The RPE8FT had greater (p < 0.001) performance fatigability than the RPE2FT, despite no difference (p > 0.05) in TTF. During both tasks, there were significant (p ≤ 0.05) composite linear decreases for torque, electromyographic amplitude, and neuromuscular efficiency, and substantial individual variability in the neuromuscular responses. There were no significant (p > 0.05) associations among the perceived factors and TTF or performance fatigability. Thus, there were RPE-specific differences in performance fatigability, but not TTF or the composite patterns of changes in torque and neuromuscular responses. In addition, in most cases, the individual neuromuscular, but not torque, patterns of responses were RPE-specific. Furthermore, the perceived factors assessed by the PTQ were not related to TTF or performance fatigability.

The effects of sustained, low- and high-intensity isometric tasks on performance fatigability and the perceived responses that contributed to task termination

PURPOSE

The present study examined the effects of sustained, isometric low- versus high-intensity tasks on time to task failure (TTF), performance fatigability (PF), ratings of perceived exertion (RPE), and the perceived causes of task termination from a post-test questionnaire (PTQ).

METHODS

Ten men (mean ± SD: age = 21.1 ± 2.3 years; height = 180.2 ± 5.7 cm; body mass = 79.5 ± 8.8 kg) performed maximal voluntary isometric contractions (MVICs) before and after fatiguing, isometric forearm flexion tasks anchored to the torque corresponding to RPE values of 2 (TRQ2FT = 23.8 ± 7.1 N·m) and 8 (TRQ8FT = 60.9 ± 11.4 N·m). In addition, the subjects completed a PTQ which surveyed whether the perceived sensations of fatigue or pain, and/or the psychological factors of loss of focus and motivation contributed to the decision to terminate the task. Repeated measures ANOVAs, Wilcoxon-Signed Rank tests, and Spearman's Rank-Order Correlations were used to analyze the data.

RESULTS

Across the fatiguing tasks, there were similar decreases in MVIC torque (95.2 ± 20.3 vs. 68.9 ± 15.6 N·m; p < 0.001) and RPE values (p = 0.122) at task failure for TRQ2FT (7.4 ± 2.7) and TRQ8FT (8.9 ± 1.0), but a longer (p = 0.005) TTF for the TRQ2FT (245.0 ± 177.0 s) than TRQ8FT (36.8 ± 11.1 s).

CONCLUSIONS

Despite reaching task failure, the subjects were able to perform MVICs that were 100-300% greater than the target torque values within seconds of terminating the tasks. Thus, we hypothesized that task failure was not caused by an inability to produce sufficient torque to sustain the tasks, but rather an unwillingness to continue the task.

Factors Associated with Elderly Health-Related Quality of Life in Tibet: A Cross-Sectional Study from a Health Ecological Perspective

Background

Aging and its consequences are receiving considerable global attention in developed and developing countries. The health-related quality of life (HRQoL) of elderly individuals is crucial for public health and social welfare. Despite advances in understanding the health status of the elderly population in Tibet, a region located on China's southwest border, a significant research gap remains regarding their HRQoL.

Methods

We conducted a cross-sectional study in Tibet, China, in 2018, which thoroughly examined HRQoL and its determinants in individuals aged 60 and above. The EQ-5D-VAS instrument, consisting of two standardized scales (EQ-5D-3L and EQ-VAS), was utilized to measure HRQoL. We based the selection of potential determinants on a novel health ecological model encompassing various environmental and personal factors. We employed the Least Absolute Shrinkage and Selection Operator regression to systematically pinpoint key predictive factors for dimensionality reduction. The Tobit regression analysis further elucidated the relationship between these factors and the EQ-VAS and EQ-5D-index scores.

Results

Our study encompassed 1604 elderly participants. They presented varying severity levels across all five dimensions of the EQ-5D-3L. The most commonly observed issue was pain/discomfort, with a prevalence of 40.27%. The average EQ-VAS score was 56.15 (SD=21.15), and the mean EQ-5D-index score was 0.78 (SD=0.25). Our multivariate analysis revealed that determinants such as age, sex, number of chronic illnesses, vision problems, hearing problems, physical activity, employment status, social participation, place of residence, and insurance type were significantly associated with HRQoL.

Conclusion

The HRQoL of Tibet's elderly population presents significant concerns, especially given the region's challenging natural conditions. This underscores the urgent need for focused policy interventions at the socio-economic strata to extend vital support and aid.