Modeling between-subject differences and within-subject changes for long distance runners by age

2018 ◽  
Vol 14 (2) ◽  
pp. 81-90
Author(s):  
Matthew Strand ◽  
Daniel Nelson ◽  
Gary Grunwald

Abstract A time-varying predictor in a longitudinal model can be separated into between- and within-subject components. This is important if a researcher is specifically interested in differences between subjects or changes within subjects. If no separation is made, then the effect associated with the time-varying predictor is a combination of the between- and within-subject effects. In this article, running race performances are considered as a nonlinear function of age, for which both absolute and relative difference terms are used to separate between- and within-subject components. Longitudinal data were obtained from 12 consecutive years of the 10-km Bolder Boulder for analysis, for the class of competitive recreational runners. Mixed models were used to fit the data after log transforming the nonlinear model. Results of model fits demonstrated that between-subject differences between ages were somewhat similar to within-subject changes, although the latter tended to change somewhat more slowly, especially after the peak racing ages. For example, the between-subject rate of change for 43 year-old runners was about 1% per year on average (increase in race time), while the within-subject change for a runner of the same age averaged between 0.6 and 0.8% per year.

2020 ◽  
Author(s):  
Kazumi Ushiki ◽  
Katsuhiko Tsunekawa ◽  
Yoshifumi Shoho ◽  
Larasati Martha ◽  
Hirotaka Ishigaki ◽  
...  

Abstract Background Overtraining syndrome, caused by prolonged excessive stress, results in reduced performance and cortisol responsiveness in athletes. It is necessary to collect saliva samples sequentially within circadian rhythm for assessing exercise stress by measuring cortisol concentrations, and automated cortisol measurements using electrochemiluminescence immunoassay (ECLIA) may be useful for measuring a large number of saliva samples. In this study, we evaluated the appropriate use of cortisol-based exercise stress assessment within the circadian rhythm, which may diagnose and prevent overtraining syndrome in athletes. Methods We collected saliva and sera from 54 healthy participants and analyzed the correlation between salivary cortisol concentrations measured by ECLIA and enzyme-linked immunosorbent assay (ELISA) or serum cortisol analysis. We also collected saliva continuously from 12 female long-distance runners on 2 consecutive days involving different intensities and types of exercise early in the morning and in the afternoon and measured salivary cortisol concentrations using ECLIA. Each exercise intensity of runners was measured by running velocities, Borg Scale score, and rate of change in the pulse rate by exercise. Results ECLIA-based salivary cortisol concentrations correlated positively with those detected by ELISA (ρ = 0.924, p < 0.001) and serum cortisol (ρ = 0.591, p = 0.001). In long-distance runners, circadian rhythm of salivary cortisol including peak after waking and decrease promptly thereafter were detected on both days by continuous saliva sampling. The rates of change in salivary cortisol concentrations were significantly lower after an early morning exercise than after an afternoon exercise on both days (day 1, p = 0.002 and day 2, p = 0.003). In the early morning exercise, the rate of change in salivary cortisol concentration was significantly higher on day 1 than on day 2 ( p = 0.034), similar to significant difference in running velocities ( p = 0.001). Conclusions Our results suggest that automated ECLIA-based salivary cortisol measurements are able to detect the athletes' circadian rhythm and compare the exercise stress intensities at the same times on different days, even in the early morning, possibly leading to prevention of overtraining syndrome.


2020 ◽  
Author(s):  
Kazumi Ushiki ◽  
Katsuhiko Tsunekawa ◽  
Yoshifumi Shoho ◽  
Larasati Martha ◽  
Hirotaka Ishigaki ◽  
...  

Abstract Background: Overtraining syndrome, caused by prolonged excessive stress, results in reduced performance and cortisol responsiveness in athletes. It is necessary to collect saliva samples sequentially within circadian rhythm for assessing exercise stress by measuring cortisol concentrations, and automated cortisol measurements using electrochemiluminescence immunoassay (ECLIA) may be useful for measuring a large number of saliva samples. In this study, we evaluated the appropriate use of cortisol-based exercise stress assessment within the circadian rhythm, which may diagnose and prevent overtraining syndrome in athletes. Methods: We collected saliva and sera from 54 healthy participants and analyzed the correlation between salivary cortisol concentrations measured by ECLIA and enzyme-linked immunosorbent assay (ELISA) or serum cortisol analysis. We also collected saliva continuously from 12 female long-distance runners on 2 consecutive days involving different intensities and types of exercise early in the morning and in the afternoon and measured salivary cortisol concentrations using ECLIA. Each exercise intensity of runners was measured by running velocities, Borg Scale score, and rate of change in the pulse rate by exercise. Results: ECLIA-based salivary cortisol concentrations correlated positively with those detected by ELISA (ρ = 0.924, p < 0.001) and serum cortisol (ρ = 0.591, p = 0.001). In long-distance runners, circadian rhythm of salivary cortisol including peak after waking and decrease promptly thereafter were detected on both days by continuous saliva sampling. The rates of change in salivary cortisol concentrations were significantly lower after an early morning exercise than after an afternoon exercise on both days (day 1, p = 0.002 and day 2, p = 0.003). In the early morning exercise, the rate of change in salivary cortisol concentration was significantly higher on day 1 than on day 2 ( p = 0.034), similar to significant difference in running velocities ( p = 0.001).Conclusions: Our results suggest that automated ECLIA-based salivary cortisol measurements are able to detect the athletes' circadian rhythm and compare the exercise stress intensities at the same times on different days, even in the early morning, possibly leading to prevention of overtraining syndrome.


2011 ◽  
Vol 4 (5) ◽  
pp. 561-564
Author(s):  
Annu Annu ◽  
◽  
Vijay Kumar ◽  
Malkeet Kaur ◽  
Neha Sharma ◽  
...  

1984 ◽  
Vol 53 (3) ◽  
pp. 213-218 ◽  
Author(s):  
Tetsuo Ohkuwa ◽  
Yoshinobu Kato ◽  
Koichi Katsumata ◽  
Takayuki Nakao ◽  
Miharu Miyamura

Nutrients ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3758
Author(s):  
Joanna Smarkusz-Zarzecka ◽  
Lucyna Ostrowska ◽  
Joanna Leszczyńska ◽  
Karolina Orywal ◽  
Urszula Cwalina ◽  
...  

Use of probiotic supplements, the benefits of which have not been proven in sportspeople, is becoming more widespread among runners. The aim of this study was to evaluate the effect of a multi-strain probiotic on body composition, cardiorespiratory fitness and inflammation in the body. The randomised, double-blind study included 66 long-distance runners. The intervention factor was a multi-strain probiotic or placebo. At the initial and final stages of the study, evaluation of body composition and cardiorespiratory fitness was performed and the presence of inflammation determined. In the group of men using the probiotic, an increase in lean body mass (p = 0.019) and skeletal muscle mass (p = 0.022) was demonstrated, while in the group of women taking the probiotic, a decrease in the content of total body fat (p = 0.600) and visceral fat (p = 0.247) was observed. Maximum oxygen consumption (VO2max) increased in women (p = 0.140) and men (p = 0.017) using the probiotic. Concentration of tumour necrosis factor-alpha decreased in women (p = 0.003) and men (p = 0.001) using the probiotic and in women (p = 0.074) and men (p = 0.016) using the placebo. Probiotic therapy had a positive effect on selected parameters of body composition and cardiorespiratory fitness of study participants and showed a tendency to reduce inflammation.


2021 ◽  
Vol 9 (7_suppl3) ◽  
pp. 2325967121S0008
Author(s):  
Mitchell J. Rauh ◽  
Micah C. Garcia ◽  
David M. Bazett-Jones ◽  
Jason T. Long ◽  
Kevin R. Ford ◽  
...  

Background: Distance running is a popular interscholastic sport, but also has an associated high risk of running-related injuries. Recent literature suggests that functional tests may help to identify athletes at increased risk of injury. The Y-Balance Test (YBT) is an objective measure used to assess functional muscle strength and balance and to expose asymmetries between tested limbs. Purpose: To determine if YBT performance was associated with maturation status in healthy, youth distance runners. We hypothesized that mid-pubertal (MP) runners would demonstrate less functional reach distance than pre-pubertal (PrP) or post-pubertal (PoP) runners. Methods: A convenience sample of 142 (Females: n=79, Males: n=63) uninjured youth runners (ages 13.5±2.7 years; weekly running distance: 18.2±20.4 km) were recruited from the local community. All runners met inclusion criteria, indicating that they were between 9 and 19 years old and participated in long-distance running activities such as school/club track and field, cross country, road races, trail running, and/or soccer. The runners completed a modified Pubertal Maturational Observation Scale (PMOS), then were screened for right (R) and left (L) anterior (ANT), posteromedial (PM) and posterolateral (PL) reach distances (cm) normalized by lower limb length (cm). Composite reach distance was calculated by the sum of the three reach distances divided by three times the limb length multiplied by 100 for R and L limbs. ANOVA with Bonferroni post hoc tests were used to compare maximum normalized reach distances for the three directions and composite reach distance by maturation status and sex. Results: Overall, 31.7% were classified as PrP status, 26.1% as MP, and 42.3% as PoP, with similar percentages by sex ( p=0.84). The only significant mean difference was found for R ANT maximum normalized reach distance between PrP and PoP ( p=0.02), indicating a greater normalized reach in PrP athletes. No significant mean differences were found for R or L PM and PL maximum normalized reach distances, or for R or L composite reach distances, by maturation status or when stratified by maturation and sex ( p>0.05). Conclusions: In this sample of youth runners, the YBT was only a discriminator of anterior reach distance between pre-pubertal and post-pubertal runners. As decreased anterior reach is associated with reduced quadriceps muscle strength and anterior knee pain, reduced anterior reach in post-pubertal runners may potentially signify an increased risk of sustaining a running-related injury. Thus, preventive efforts to ensure good functional quadriceps muscle strength may be merited.


2019 ◽  
Vol 24 ◽  
pp. 121-128
Author(s):  
Sigal Ben-Zaken ◽  
Yoav Meckel ◽  
Dan Nemet ◽  
Alon Eliakim

The ACSL A/G polymorphism is associated with endurance trainability. Previous studies have demonstrated that homozygotes of the minor AA allele had a reduced maximal oxygen consumption response to training compared to the common GG allele homozygotes, and that the ACSL A/G single nucleotide polymorphism explained 6.1% of the variance in the VO2max response to endurance training. The contribution of ACSL single nucleotide polymorphism to endurance trainability was shown in nonathletes, however, its potential role in professional athletes is not clear. Moreover, the genetic basis to anaerobic trainability is even less studied. Therefore, the aim of the present study was to examine the prevalence of ACSL single nucleotide polymorphism among professional Israeli long distance runners (n=59), middle distance runners (n=31), sprinters and jumpers (n=48) and non-athletic controls (n=60). The main finding of the present study was that the ACSL1 AA genotype, previously shown to be associated with reduced endurance trainability, was not higher among sprinters and jumpers (15%) compared to middle- (16%) and long-distance runners (15%). This suggests that in contrast to previous studies indicating that the ACSL1 single nucleotide polymorphism may influence endurance trainability among non-athletic individuals, the role of this polymorphism among professional athletes is still not clear.


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