Time of Day Effects on Anaerobic Performance Using a Nonmotorized Treadmill.

ABSTRACT: Renziehausen, JM, Bergquist, AM, Park, J-H, Hill, EC, Wells, AJ, Stout, JR, and Fukuda, DH. Time of day effects on anaerobic performance using a nonmotorized treadmill. J Strength Cond Res 37(10): 2002-2007, 2023-The purpose of this study was to determine the effects of time of day on performance during a maximal effort sprinting assessment (30nmt) and determine potential differences based on chronotype and sex. Twenty-six recreationally active men (n = 12) and women (n = 14) between the ages of 18 and 35 years old (21.5 ± 2.4 years) completed the 30nmt at 9:00 am, 2:00 pm, and 7:00 pm in a randomized order over a 24-hour period. Resting heart rate and temperature assessments were taken at each visit. A dietary recall and the Morningness-Eveningness Questionnaire were used to assess kilocalories (kcals) and chronotype, respectively. Two-way (time x sex) repeated measures analyses of variance were conducted to determine differences in peak/mean power, peak/mean velocity, distance, resting heart rate, temperature, and kcals at each time point. Paired sample t tests were used to assess peak and nadir of each performance variable. A significance level was set at p < 0.05. There was a significant main effect for temperature (p < 0.001), resting heart rate (p = 0.007), and pre-exercise caloric intake (p = 0.021) throughout the day. No significant main effects for time were found for peak power (p = 0.766), mean power (p = 0.094), peak velocity (p = 0.497), mean velocity (p = 0.193), or distance (p = 0.262). There were no significant time × sex interactions for any dependent performance variables (p > 0.05). Significant differences were shown between the peak and nadir of each performance variable (p < 0.001). There were no significant differences in performance during maximal effort anaerobic assessments shown throughout the day; however, peak/nadir of performance times may be individualized and differ between morning types and intermediate types.

Body composition, fear of falling and balance performance in community-dwelling older adults.

Objectives: We aimed to 1) assess body composition using a portable technology, bioelectrical impedance analysis, (BIA) and 2) examine the associations between body composition and the discrepancy of fear of falling (FOF) and balance performance. Methods: A cross-sectional study included 121 older adults 60 years and older, 78% were female, 41% lived alone, and 71% had no history of falls. The discrepancy between fear of falling and balance performance was categorized into four groups. We found 47% rational (low FOF and normal balance), 19% incongruent (low FOF despite poor balance), 18% irrational (high FOF despite normal balance), and 16% congruent (high FOF and poor balance). Results: Body Fat Mass (BFM), Percent Body Fat (PBF), and Body Mass Index (BMI) were correlated with fear of falling and balance performance. BMI was significantly different in the rational group (p = 0.004) and incongruent group (p = 0.02) compared to the congruent group. PBF was significantly different between the incongruent (p = 0.002), irrational (p = 0.014), and rational (p < 0.001) groups, compared to the congruent group. Conclusions: The study found that body BFM, PBF, and BMI were correlated with fear of falling and balance impairment. High Body Mass Index and Body Fat Mass were associated with a discrepancy between FOF and balance. Body composition analysis devices, such as BIA and other portable technologies, could be taken to underserved communities and may help identify community-dwelling older adults who are frail and may be at high risk of falling.

Effects of a Multi-Ingredient Oral Supplement on Multiple Object Tracking, Reaction Time, and Reactive Agility.

Background: The demands of typical daily activities require a constant level of alertness and attention. Multi-ingredient, caffeine-containing supplements have been shown to improve measures of cognitive performance. As many of these supplements become readily available, efficacy of each should be evaluated. Therefore, the purpose of this study is to examine the effects of the 4D dietary supplement on cognition, reaction time, and reactive agility. Methods: Seventeen healthy males (n = 8) and females (n = 9) between the ages of 18-40 years old (22.8 ± 2.9 years; 167.3 ± 9.6 cm; 65.4 ± 10.9 kg) participated in this double-blind, randomized crossover study. Participants completed three baseline reaction time assessments on the Dynavision and one baseline multiple object tracking assessment on the Neurotracker. Participants then consumed the oral multi-ingredient supplement containing 150 mg of caffeine or non-caffeinated placebo, mixed with 24 ounces of water, and rested for 45 minutes. Following the rest period, participants completed an additional three reaction time assessments and one multiple object tracking (MOT) assessment, as well as 6-12 trials of the Y-reactive agility test. Repeated measures ANOVAs were used to evaluate YRA performance and change values for Dynavision RT, Dynavision score, and MOT speed with either 4D dietary supplement or placebo. Results: A significant time × supplement interaction was shown for MOT speed (p = .040, d = .543). Change scores in MOT speed were significantly different from zero following 4D (mean: 0.224 au; 95% confidence interval: 0.050 to 0.398 au) but not placebo supplementation (mean: -0.046 au; 95% confidence interval: -0.220 to 0.127 au). No time × supplement interaction was shown for Dynavision RT (p = .056, d = -.499) or Dynavision score (p = .093, d = .434). No differences were shown for YRA scores following supplementation for the right side (p = .241, d = -.295) or left side (p = .378, d = -.220). Conclusion: The 4D dietary supplement appears to improve measures of cognition, specifically attention/spatial awareness, but not reaction time or reactive agility. Future research should examine the effects of this supplement with a larger, less heterogeneous sample and/or in conjunction with an exercise intervention.

Effects of Interrupted Daily Routine Due to COVID-19 on Circadian Chronotype and Leisure Time Physical Activity.

Circadian chronotype is dependent on many factors including age, physical activity participation, eating and sleeping patterns, and typical schedule. Recently, the COVID-19 pandemic resulted in schedule changes for most individuals. Therefore, the purpose of this study is to examine whether sport participation influences circadian chronotype and physical activity and whether COVID-19 restrictions have impacted chronotype scores. Briefly, 128 physically active males (n = 62) and females (n = 66) between 18 and 55 years old (24.7 ± 7.1) completed a survey consisting of demographics information, the Morningness−Eveningness Questionnaire (MEQ), and the Godin Leisure Time Physical Activity Scale (LTPA). Participants were asked to answer relevant questions about their habits/preferences before and after COVID-19-related restrictions were implemented. MEQ scores categorized individuals into morning (MT), intermediate (IT), and evening (ET) chronotypes. Three-way (pre-COVID-19 chronotype x sport participation x time) repeated measures ANOVA was conducted to evaluate differences in MEQ and LTPA. A significant main effect of time was found for MEQ (p = 0.018) and LTPA (p = 0.002), indicating changes following COVID-19. A significant time x chronotype interaction was shown for MEQ (p < 0.001) with MT (p < 0.001), IT (p = 0.044), and ET (p = 0.044) individuals indicating chronotype-specific changes following COVID-19. LTPA was decreased and MEQ scores changed following COVID-19, with shifts toward IT scores.